阅读说明：本技术 永磁电磁混合悬浮的抓取方法及抓取装置 (Permanent magnet and electromagnetic mixed suspension grabbing method and grabbing device ) 是由 张则羿 于 2021-09-15 设计创作，主要内容包括：本发明提供一种永磁电磁混合悬浮的抓取方法及抓取装置,包括：向电磁铁提供初始恒定励磁电流；按照预设采样时刻获取抓取部与待抓取物体之间的距离实测值,并调整距离设定值,将每一预设采样时刻的距离实测值与该预设采样时刻对应的距离设定值进行比较：若距离实测值大于对应的距离设定值,启动第一电机和/或第二电机以匀速减小抓取部与待抓取物体之间的距离,直至距离实测值减小至小于或等于距离设定值,停止第一电机和第二电机；基于距离实测值与距离设定值的差值调节电磁铁中励磁电流的方向和大小,以调整抓取部与待抓取物体之间的磁场力。本发明的磁悬浮抓取方法,能够避免在抓取过程中产生机械接触,杜绝交叉污染。(The invention provides a permanent magnet and electromagnetic mixed suspension grabbing method and device, comprising the following steps: providing an initial constant excitation current to the electromagnet; acquiring the distance measured value between the grabbing part and the object to be grabbed according to the preset sampling time, adjusting the distance set value, and comparing the distance measured value at each preset sampling time with the distance set value corresponding to the preset sampling time: if the measured distance value is larger than the corresponding distance set value, starting the first motor and/or the second motor to reduce the distance between the grabbing part and the object to be grabbed at a constant speed until the measured distance value is reduced to be smaller than or equal to the distance set value, and stopping the first motor and the second motor; and adjusting the direction and the magnitude of the exciting current in the electromagnet based on the difference value between the actual distance measurement value and the distance set value so as to adjust the magnetic field force between the grabbing part and the object to be grabbed. The magnetic suspension grabbing method can avoid mechanical contact in the grabbing process and avoid cross contamination.)

1. The utility model provides a permanent magnetism electromagnetism mixes method of snatching of suspension for snatch the object of waiting to snatch that is located under the portion of snatching through the portion of snatching contactless, the fixed electro-magnet that is provided with of lower terminal surface of the portion of snatching, the fixed permanent magnet that is provided with of the up end of waiting to snatch the object, the portion of snatching can realize the up-and-down motion of vertical direction through first motor, the object of waiting to snatch can realize the up-and-down motion of vertical direction through the second motor, its characterized in that includes:

step one, providing initial constant exciting current for an electromagnet;

step two, acquiring distance measured values between the grabbing part and the object to be grabbed according to preset sampling moments, adjusting distance set values, and comparing the distance measured values at each preset sampling moment with the distance set values corresponding to the preset sampling moments:

if the measured distance value is larger than the corresponding distance set value, starting the first motor and/or the second motor to reduce the distance between the grabbing part and the object to be grabbed at a constant speed until the measured distance value is reduced to be smaller than or equal to the distance set value, and stopping the first motor and the second motor;

and thirdly, adjusting the direction and the size of the exciting current in the electromagnet based on the difference value between the measured distance value and the set distance value so as to adjust the magnetic field force between the grabbing part and the object to be grabbed.

2. The capturing method of the permanent magnet and electromagnetic hybrid suspension as claimed in claim 1, wherein in the second step, adjusting the distance setting value comprises:

and updating the distance set value according to a distance theoretical value, wherein the distance theoretical value is a predicted value of the distance between the grabbing part and the object to be grabbed after a plurality of sampling cycles.

3. The capturing method of the permanent magnet and electromagnetic hybrid suspension as claimed in claim 1, wherein in the second step, adjusting the distance setting value comprises:

acquiring a distance calculation value according to a preset time interval;

the distance set value is updated based on the acquired distance calculation value.

4. The grabbing method of the permanent magnet and electromagnetic hybrid suspension of claim 3, wherein the distance calculation value is calculated according to the following formula:

wherein i is a natural number; y is_sp0(t_i) Is t_iCalculating the distance of the moment; y (t)_i) Is t_iA measured value of the distance of the time; y' (t)_i) Is t_iThe time rate of change of the measured distance value at that moment; t is t_i-1＝t_i-ΔT；t_i-2＝t_i-1- Δ T; Δ T is a preset time interval; alpha is a safety coefficient and is more than or equal to 1; beta is a safety constant, and beta<0。

5. The grabbing method of the permanent magnet and electromagnetic hybrid suspension according to claim 1, wherein the distance setting value comprises a first distance setting value and a second distance setting value; in the second step, adjusting the distance set value comprises:

alternately acquiring a first distance calculation value and a second distance calculation value according to a preset time interval;

and updating the first distance set value based on the acquired first distance calculation value, and updating the second distance set value based on the acquired second distance calculation value.

6. The capturing method of claim 5, wherein the step two of comparing the measured distance value at each preset sampling time with the set distance value corresponding to the preset sampling time comprises:

comparing the distance measured value at each preset sampling moment with a distance set value corresponding to the preset sampling moment, wherein the distance set value corresponding to the preset sampling moment is a first distance set value or a second distance set value.

7. The grabbing method of the permanent magnet and electromagnetic hybrid suspension as claimed in claim 5, wherein the first distance calculation value is calculated according to the following formula:

wherein i is a natural number; y is_sp1(t_1,i) Is t_1,iCalculating a first distance value of the moment; y (t)_1,i) Is t_1,iA measured value of the distance of the time; y' (t)_1,i) Is t_1,iThe time rate of change of the measured distance value at that moment; t is t_1,i-1＝t_1,i-ΔT；t_1,i-2＝t_1,i-1- Δ T; Δ T is a preset time interval; alpha is a safety coefficient and is more than or equal to 1; beta is a safety constant, and beta<0；

The second distance calculation value is calculated according to the following formula:

wherein i is a natural number; y is_sp2(t_2,i) Is t_2,iCalculating a second distance value of the moment; y (t)_2,i) Is t_2,iA measured value of the distance of the time; y' (t)_2,i) Is t_2,iThe time rate of change of the measured distance value at that moment; t is t_2,i＝t_1,i+ΔT/2；t_2,i-1＝t_2,i-ΔT；t_2,i-2＝t_2,i-1- Δ T; Δ T is a preset time interval; alpha is a safety coefficient and is more than or equal to 1; beta is a safety constant, and beta<0。

8. The utility model provides a grabbing device that mixed suspension of permanent magnetism electromagnetism for snatch the object of waiting to snatch that is located under the portion of snatching through the portion of snatching contactless, the fixed electro-magnet that is provided with of terminal surface under the portion of snatching, the fixed permanent magnet that is provided with of up end of waiting to snatch the object, the portion of snatching can realize the up-and-down motion of vertical direction through first motor, wait to snatch the object and can realize the up-and-down motion of vertical direction through the second motor, a serial communication port, include:

the exciting current setting module is used for providing initial constant exciting current for the electromagnet;

the acquisition module is used for acquiring a measured distance value between the grabbing part and an object to be grabbed;

the adjusting module is used for adjusting the distance set value;

the comparison module is used for comparing the distance measured value with a distance set value and outputting a comparison result;

the motor control module is used for controlling the starting and stopping of the first motor and/or the second motor according to the comparison result output by the comparison module; and

and the suspension control module is used for adjusting the direction and the size of the exciting current in the electromagnet based on the difference value between the distance measured value and the distance set value so as to adjust the magnetic field force between the grabbing part and the object to be grabbed.

9. The permanent-magnet electromagnetic hybrid levitation gripping device as recited in claim 8,

the motor control module is used for starting the first motor and/or the second motor to reduce the distance between the grabbing part and the object to be grabbed at a constant speed under the condition that the measured distance value is greater than the corresponding distance set value until the measured distance value is reduced to be less than or equal to the distance set value, and stopping the first motor and the second motor;

the suspension control module is used for adjusting the direction and the size of exciting current in the electromagnet based on the difference value between the distance measured value and the distance set value after the first motor and the second motor stop so as to adjust the magnetic field force between the grabbing part and the object to be grabbed.

10. A machine-readable storage medium having stored thereon instructions for causing a machine to perform the method of grabbing a permanent magnet-electromagnetic hybrid levitation of any one of claims 1-7 herein.

Technical Field

The invention relates to the technical field of permanent magnet and electromagnetic hybrid suspension, in particular to a grabbing method of permanent magnet and electromagnetic hybrid suspension, a grabbing device of permanent magnet and electromagnetic hybrid suspension and a machine readable storage medium.

Background

In the prior art, a contact grabbing mode is generally adopted in the object carrying process, and the mode can cause mechanical contact between the object and the grabbing mechanism, so that the deformation of the object and the cross contamination caused by taking the grabbing mechanism as a medium between the grabbed objects are easily caused. For certain scenarios with higher cleanliness requirements, cross-contamination of contact gripping means will result in unacceptable cleanliness of a batch of products, and therefore non-contact gripping means are highly desirable. Magnetic suspension grabbing is carried out in a non-contact mode by utilizing the acting force of a magnetic field between a grabbing part and an object to be grabbed, so that the grabbing part and the object to be grabbed are not in mechanical contact in the grabbing process, and cross pollution is avoided; and the grabbing control process is optimized, so that grabbing with low power consumption, high precision and high stability is realized.

Magnetic levitation grasping involves the grasping and transporting process of an object. However, the existing magnetic levitation technology usually needs human assistance to achieve the magnetic levitation effect, and a proper automatic grabbing method is not available. For example, chinese patent application No. 03142900.9 discloses an apparatus for supporting an object, which is balanced by magnetic force and gravity without support of the object, and which changes the direction and magnitude of current according to the position of the object relative to a dynamic balance point to achieve stable levitation of the object, but lacks a corresponding grasping method. Therefore, the invention provides a permanent magnet and electromagnetic mixed suspension grabbing method, which realizes non-contact automatic grabbing of an object to be grabbed.

Disclosure of Invention

The invention aims to provide a permanent magnet and electromagnetic mixed suspension grabbing method and a grabbing device, which at least solve the problem of contact pollution caused by the contact grabbing mode.

In order to achieve the above object, a first aspect of the present invention provides a permanent magnet and electromagnetic hybrid suspension grabbing method for grabbing an object to be grabbed directly below a grabbing portion in a non-contact manner by using the grabbing portion, wherein an electromagnet is fixedly disposed on a lower end surface of the grabbing portion, a permanent magnet is fixedly disposed on an upper end surface of the object to be grabbed, the grabbing portion can achieve vertical up-and-down movement by using a first motor, and the object to be grabbed can achieve vertical up-and-down movement by using a second motor, the method including:

step one, providing initial constant exciting current for an electromagnet;

step two, acquiring the distance measured value between the grabbing part and the object to be grabbed in real time according to the preset sampling time, adjusting the distance set value, and comparing the distance measured value at each preset sampling time with the distance set value corresponding to the preset sampling time:

if the measured distance value is larger than the corresponding distance set value, starting the first motor and/or the second motor to reduce the distance between the grabbing part and the object to be grabbed at a constant speed until the measured distance value is reduced to be smaller than or equal to the distance set value, and stopping the first motor and the second motor;

and thirdly, adjusting the direction and the size of the exciting current in the electromagnet based on the difference value between the measured distance value and the set distance value so as to adjust the magnetic field force between the grabbing part and the object to be grabbed.

Optionally, in step two, adjusting the distance setting value includes:

and updating the distance set value according to a distance theoretical value, wherein the distance theoretical value is a predicted value of the distance between the grabbing part and the object to be grabbed after a plurality of sampling cycles.

Optionally, in step two, adjusting the distance setting value includes:

acquiring a distance calculation value according to a preset time interval;

the distance set value is updated based on the acquired distance calculation value.

Optionally, the distance calculation value is calculated according to the following formula:

wherein i is a natural number; y is_sp0(t_i) Is t_iCalculating the distance of the moment; y (t)_i) Is t_iA measured value of the distance of the time; y' (t)_i) Is t_iThe time rate of change of the measured distance value at that moment; t is t_i-1＝t_i-ΔT；t_i-2＝t_i-1- Δ T; Δ T is a preset time interval; alpha is a safety coefficient and is more than or equal to 1; beta is a safety constant, and beta<0。

Optionally, the distance setting value includes a first distance setting value and a second distance setting value; in the second step, adjusting the distance set value comprises:

alternately acquiring a first distance calculation value and a second distance calculation value according to a preset time interval;

and updating the first distance set value based on the acquired first distance calculation value, and updating the second distance set value based on the acquired second distance calculation value.

Optionally, in the second step, comparing the measured distance value at each preset sampling time with the distance setting value corresponding to the preset sampling time, includes:

comparing the distance measured value at each preset sampling moment with a distance set value corresponding to the preset sampling moment, wherein the distance set value corresponding to the preset sampling moment is a first distance set value or a second distance set value.

Optionally, the first distance calculation value is calculated according to the following formula:

wherein i is a natural number; y is_sp1(t_1,i) Is t_1,iCalculating a first distance value of the moment; y (t)_1,i) Is t_1,iA measured value of the distance of the time; y' (t)_1,i) Is t_1,iThe time rate of change of the measured distance value at that moment; t is t_1,i-1＝t_1,i-ΔT；t_1,i-2＝t_1,i-1- Δ T; Δ T is a preset time interval; alpha is a safety coefficient and is more than or equal to 1; beta is a safety constant, and beta<0；

The second distance calculation value is calculated according to the following formula:

wherein i is a natural number; y is_sp2(t_2,i) Is t_2,iCalculating a second distance value of the moment; y (t)_2,i) Is t_2,iA measured value of the distance of the time; y' (t)_2,i) Is t_2,iThe time rate of change of the measured distance value at that moment; t is t_2,i＝t_1,i+ΔT/2；t_2,i-1＝t_2,i-ΔT；t_2,i-2＝t_2,i-1- Δ T; Δ T is a preset time interval; alpha is a safety coefficient and is more than or equal to 1; beta is a safety constant, and beta<0。

The invention provides a permanent-magnet-electromagnetic hybrid suspension grabbing device, which is used for grabbing an object to be grabbed positioned right below a grabbing part in a non-contact manner through the grabbing part, wherein an electromagnet is fixedly arranged on the lower end face of the grabbing part, a permanent magnet is fixedly arranged on the upper end face of the object to be grabbed, the grabbing part can realize vertical up-and-down motion through a first motor, and the object to be grabbed can realize vertical up-and-down motion through a second motor, and the permanent-magnet-electromagnetic hybrid suspension grabbing device comprises:

the exciting current setting module is used for providing initial constant exciting current for the electromagnet;

the acquisition module is used for acquiring a measured distance value between the grabbing part and an object to be grabbed;

the adjusting module is used for adjusting the distance set value;

the comparison module is used for comparing the distance measured value with a distance set value and outputting a comparison result:

the motor control module is used for controlling the starting and stopping of the first motor and/or the second motor according to the comparison result output by the comparison module; and

and the suspension control module is used for adjusting the direction and the size of the exciting current in the electromagnet based on the difference value between the distance measured value and the distance set value so as to adjust the magnetic field force between the grabbing part and the object to be grabbed.

Optionally, the motor control module is configured to start the first motor and/or the second motor to decrease the distance between the grasping portion and the object to be grasped at a constant speed when the measured distance value is greater than the corresponding distance set value, and stop the first motor and the second motor until the measured distance value is decreased to be less than or equal to the distance set value;

the suspension control module is used for adjusting the direction and the size of exciting current in the electromagnet based on the difference value between the distance measured value and the distance set value after the first motor and the second motor stop so as to adjust the magnetic field force between the grabbing part and the object to be grabbed.

In another aspect, the present invention provides a machine-readable storage medium having stored thereon instructions for causing a machine to execute the above-mentioned grabbing method for permanent magnet-electromagnetic hybrid levitation.

The invention has the advantages that:

1. the invention balances the gravity of the object to be grabbed by combining the permanent magnetic attraction between the iron core of the electromagnet and the permanent magnet on the object to be grabbed and the controllable electromagnetic force between the electromagnet and the permanent magnet on the object to be grabbed, realizes non-contact magnetic suspension grabbing and solves the problem of cross contamination.

2. The grabbing mode of permanent magnet and electromagnetic mixed suspension is adopted, the grabbing stability is high, the energy consumption in the grabbing process is low, the noise is low, and the grabbing with heavy weight can be realized.

Additional features and advantages of embodiments of the invention will be set forth in the detailed description which follows.

Drawings

The accompanying drawings, which are included to provide a further understanding of the embodiments of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the embodiments of the invention without limiting the embodiments of the invention. In the drawings:

FIG. 1 is a schematic structural diagram of a permanent magnet and electromagnetic hybrid levitation grasping system provided by the invention;

FIG. 2 is a schematic diagram showing the positional relationship between the electromagnets and the distance sensors of the permanent-magnet and electromagnetic hybrid levitation grasping system provided by the invention;

FIG. 3 is a flow chart of a grabbing method of permanent magnet electromagnetic hybrid levitation provided by the invention;

FIG. 4 is a schematic diagram illustrating the active levitation control principle of the grabbing method of permanent magnet and electromagnetic hybrid levitation provided by the present invention;

fig. 5 is a schematic diagram of a variation relationship among a distance measured value, a distance set value and a current value provided in embodiment 1 of the present invention;

fig. 6 is a schematic diagram of a partial variation relationship between a measured distance value and a set distance value provided in embodiment 1 of the present invention;

fig. 7 is a schematic diagram of a variation relationship among a distance measured value, a distance set value and a current value provided in embodiment 2 of the present invention;

fig. 8 is a schematic diagram of a partial variation relationship between a measured distance value and a set distance value provided in embodiment 2 of the present invention;

fig. 9 is a schematic diagram of a variation relationship among a distance measured value, a distance set value and a current value provided in embodiment 3 of the present invention;

fig. 10 is a schematic diagram of a partial variation relationship between the measured distance value and the set distance value provided in embodiment 3 of the present invention.

Description of the reference numerals

1-a grasping section; 2-an object to be grabbed; 3-a first motor;

4-a support bar; 5-a second motor; 6-a support frame;

7-a tray; 11-a distance receptor; 12-a levitation controller;

13-a power amplification circuit; 14-an electromagnet; 15-set point adjuster;

16-a grip controller; 21-permanent magnet.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

Fig. 1 is a schematic structural diagram of a gripping system provided by the present invention, and fig. 2 is a schematic positional relationship between an electromagnet and a distance receptor of a permanent-magnet-electromagnetic hybrid levitation gripping system provided by the present invention; as shown in fig. 1-2, the grabbing system uses the permanent magnet and electromagnetic hybrid levitation grabbing method provided by the present invention to grab an object 2 to be grabbed directly below the grabbing part 1 in a non-contact manner by the grabbing part 1, where the grabbing part 1 includes: a distance receptor 11, a levitation controller 12, a power amplification circuit 13, an electromagnet 14, a set value adjuster 15, and a grasping controller 16. The electromagnet 14 is arranged on the lower end face of the grabbing part 1, the permanent magnet 21 is arranged on the upper end face of the object 2 to be grabbed, the electromagnet 14 is opposite to the permanent magnet 21, and the object 2 to be grabbed is used for bearing articles to be conveyed and can be set to be in a shape of a circle, a rectangle and the like with an accommodating space. The grabbing part 1 is connected with a first motor 3, vertical up-and-down movement is realized through the operation of the first motor 3, and the first motor 3 is arranged on a support rod 4 and can reciprocate along the support rod 4 under the action of traction force provided by a traction mechanism (not shown); similarly, the object 2 to be grabbed realizes the up-and-down movement in the vertical direction through the operation of the second motor 5, and the second motor 5 is fixedly arranged on the support frame 6. Specifically, by arranging the tray 7 connected to the second motor 5 and placing the object 2 to be grasped on the upper surface of the tray 7, the tray 7 and the object 2 to be grasped move up and down in the vertical direction by the operation of the second motor 5. When the distance between the grabbing part 1 and the object 2 to be grabbed needs to be reduced, the height of the grabbing part 1 is lowered at a constant speed by starting the first motor 3 and/or the height of the object 2 to be grabbed is raised at a constant speed by starting the second motor 5, so that the distance between the grabbing part 1 and the object 2 to be grabbed is reduced at a constant speed. The proximity sensor 11 is disposed on the lower end surface of the electromagnet 14 and electrically connected to the levitation controller 12 and the capture controller 16, the levitation controller 12 is electrically connected to the power amplifier circuit 13, the setting value adjuster 15, and the capture controller 16, and the power amplifier circuit 13 is electrically connected to the electromagnet 14 and the power supply. The distance receptor 11 is used for measuring the distance between the grabbing part 1 and the object 2 to be grabbed; the levitation controller 12 is configured to generate a control signal for adjusting an excitation current in the electromagnet 14; the power amplifying circuit 13 generates exciting current with corresponding direction and magnitude according to the control signal; the set value adjuster 15 is for adjusting a distance set value; the grasping controller 16 is configured to compare the measured distance value with a set distance value to determine the grasping state, and is further configured to control the start and stop of the first motor 3 and the second motor 5.

Fig. 3 is a flowchart of a grabbing method of permanent magnet and electromagnetic hybrid levitation provided by the present invention, as shown in fig. 3, the method includes:

step one, providing initial constant exciting current for the electromagnet 14;

specifically, an initial constant excitation current is supplied to the electromagnet 14, and the power amplification circuit 13 may be controlled by the levitation controller 12 to supply the initial constant excitation current to the electromagnet 14, which may be zero or a fixed direction and have a small absolute value. When the initial constant exciting current of the electromagnet 14 is zero, a permanent magnetic attraction force can be generated between the iron core of the electromagnet 14 and the permanent magnet 21 of the object 2 to be grabbed, and along with the decrease of the distance between the grabbing part 1 and the object 2 to be grabbed, the permanent magnetic attraction force is gradually increased and can overcome the gravity of the object 2 to be grabbed, so that the object 2 to be grabbed is separated from the tray 7 and is rapidly lifted. When the initial constant excitation current of the electromagnet 14 is in a fixed direction and has a small absolute value, an electromagnetic force (electromagnetic attraction or electromagnetic repulsion) can be generated between the electromagnet 14 and the permanent magnet 21; specifically, when the direction of the exciting current in the electromagnet 14 is positive, an electromagnetic attraction force is generated between the electromagnet 14 and the permanent magnet 21; when the direction of the exciting current in the electromagnet 14 is negative, an electromagnetic repulsive force is generated between the electromagnet 14 and the permanent magnet 21; and, because the absolute value of the initial constant exciting current is small, when the distance between the grabbing part 1 and the object 2 to be grabbed is small enough, the permanent magnetic attraction can overcome the gravity and the electromagnetic force of the object 2 to be grabbed, so that the object 2 to be grabbed is separated from the tray 7 and is rapidly lifted.

Further, if the initial constant excitation current of the electromagnet 14 is zero, the gravity is overcome by using the permanent magnetic attraction, so that the energy consumption in the grabbing process can be reduced; in the process of rapidly lifting the object 2 to be grabbed, the time for switching on the current of the electromagnet 14 is short, the power consumption is low, the heating problem of the electromagnet 14 is greatly reduced, and the service life of the electromagnet 14 can be prolonged.

Step two, acquiring a distance measured value between the grabbing part 1 and the object 2 to be grabbed according to preset sampling moments, adjusting a distance set value, and comparing the distance measured value at each preset sampling moment with the distance set value corresponding to the preset sampling moment:

if the measured distance value is larger than the corresponding set distance value, starting the first motor 3 and/or the second motor 5 to reduce the distance between the grabbing part 1 and the object 2 to be grabbed at a constant speed until the measured distance value is reduced to be smaller than or equal to the set distance value, and stopping the first motor 3 and the second motor 5;

specifically, a distance measured value between the grasping portion 1 and the object 2 to be grasped is obtained by the distance receptor 11 at a preset sampling time, and the distance receptor 11 may be provided in one or more and spaced apart from the lower end surface of the grasping portion 1 for detecting the distance measured value between the grasping portion 1 and the object 2 to be grasped; the distance sensor 11 may be a laser distance sensor or a hall element.

Further, the distance measured values are specifically: the distance sensor 11 outputs a voltage signal or a current signal representing the measured distance, and there is a one-to-one correspondence between the measured distance and the voltage signal (or the current signal), for example, the closer (or the farther) the distance, the larger the voltage signal (or the current signal) is. In addition, the voltage signal (or current signal) has both a linear and a non-linear relationship with distance. When the voltage signal (or the current signal) is in a linear relation with the distance (such as a laser distance sensor), the conversion function between the measured distance value and the voltage signal (or the current signal) is a straight line; when the voltage signal (or the current signal) is in a non-linear relationship with the distance (for example, a hall element), the conversion function between the measured distance value and the voltage signal (or the current signal) is a curve.

Specifically, the distance setting value may be adjusted in real time or at preset time intervals by the setting value adjuster 15. If a mode of adjusting the distance set value in real time is adopted, adjusting the current distance set value according to a distance theoretical value in each sampling period, wherein the distance theoretical value is a distance predicted value between a grabbing part and an object to be grabbed after a plurality of sampling periods (5-20 sampling periods); if the distance set value is adjusted according to the preset time interval, the distance set value is adjusted after each complete preset time interval (including 5-100 sampling periods, and each sampling period is 1-20 ms).

Specifically, at each preset sampling time, the distance sensor 11 measures a measured distance value between the grasping portion 1 and the object 2 to be grasped, and transmits the measured distance value to the grasping controller 16, the grasping controller 16 compares the measured distance value with a set distance value corresponding to the preset sampling time, and if the measured distance value is greater than the set distance value corresponding to the preset sampling time, the first motor 3 and/or the second motor 5 is/are started to reduce the distance between the grasping portion 1 and the object 2 to be grasped at a constant speed; until the measured distance value is reduced to be less than or equal to the set distance value, at the moment, the magnetic field suction force applied to the object 2 to be grabbed is greater than gravity, the object 2 to be grabbed is separated from the tray 7 and is rapidly lifted, and the first motor 3 and the second motor 5 are immediately stopped.

Further, the starting of the first motor 3 and/or the second motor 5 to reduce the distance between the gripping part 1 and the object 2 to be gripped at a uniform speed includes:

the first motor 3 is started by the grabbing controller 16 to lower the height of the grabbing part 1 at a constant speed and/or the second motor 5 is started by the grabbing controller 16 to raise the height of the object 2 to be grabbed at a constant speed, so as to reduce the distance between the grabbing part 1 and the object 2 to be grabbed at a constant speed. The first motor 3 and the second motor 5 may be replaced by a cylinder, an electric cylinder, or the like.

And thirdly, adjusting the direction and the magnitude of the exciting current in the electromagnet 14 based on the difference value between the measured distance value and the set distance value so as to adjust the magnetic field force between the grabbing part 1 and the object 2 to be grabbed and realize magnetic levitation grabbing.

Specifically, fig. 4 is a schematic diagram of an active levitation control principle of the permanent-magnet-electromagnetic hybrid levitation grasping method provided by the present invention, as shown in fig. 4, the levitation controller 12 generates a corresponding control signal according to a control algorithm based on a difference between an actual distance measurement value and a distance setting value, and transmits the control signal to the power amplifying circuit 13, and the power amplifying circuit 13 adjusts the direction and magnitude of the exciting current in the electromagnet 14 according to the control signal to adjust the magnetic field force between the grasping portion 1 and the object 2 to be grasped, so that the object 2 to be grasped is stably levitated at a position corresponding to the distance setting value, thereby implementing magnetic levitation grasping. For example: when the distance measured value is larger than the distance set value due to the environmental disturbance, the levitation controller 12 correspondingly adjusts the exciting current in the electromagnet 14, so as to increase the magnetic field attraction between the electromagnet 14 and the permanent magnet 21, and lift the object 2 to be grabbed, so as to lower the distance measured value, and vice versa.

In another embodiment, the method further comprises: after the magnetic suspension grabbing is realized, the object 2 to be grabbed is transported by controlling the movement of the grabbing part 1 in the horizontal and vertical directions, and the active suspension control in the fourth step is continued in the transportation process.

The levitation controller 12 can adopt an analog control circuit or a digital control program; specifically, the levitation controller 12 may be implemented by an analog control circuit, and by PID (Proportional-Integral-Derivative) closed-loop control; or a digital control program can be adopted, a signal of a distance measured value is obtained by depending on the high frequency of a single chip microcomputer, a diversified control algorithm is adopted, a corresponding control signal is generated and transmitted to the power amplification circuit 13, and the power amplification circuit 13 adjusts the direction and the magnitude of the exciting current in the electromagnet 14 according to the control signal, specifically, a fuzzy control algorithm and a predictive control algorithm are adopted.

The power amplifying circuit 13 can realize the amplification bias, the forward amplification or the reverse amplification of the current, so as to change the direction and the size of the exciting current in the electromagnet 14, and the power amplifying circuit 13 is integrated on the circuit board. In another embodiment, an H-bridge circuit may be further provided, and the change of the direction of the exciting current can be realized through the H-bridge circuit, and then the change of the magnitude of the exciting current is realized through the power amplifying circuit 13; furthermore, the control of the current direction can be realized by means of a commutator, a relay, a switch and the like.

The invention provides a permanent-magnet-electromagnetic hybrid suspension grabbing device, which is used for grabbing an object to be grabbed positioned right below a grabbing part in a non-contact manner through the grabbing part, wherein an electromagnet is fixedly arranged on the lower end face of the grabbing part, a permanent magnet is fixedly arranged on the upper end face of the object to be grabbed, the grabbing part can realize vertical up-and-down motion through a first motor, and the object to be grabbed can realize vertical up-and-down motion through a second motor, and the permanent-magnet-electromagnetic hybrid suspension grabbing device comprises:

the exciting current setting module is used for providing initial constant exciting current for the electromagnet;

the acquisition module is used for acquiring a measured distance value between the grabbing part and an object to be grabbed;

the adjusting module is used for adjusting the distance set value;

the comparison module is used for comparing the distance measured value with a distance set value and outputting a comparison result:

the motor control module is used for controlling the starting and stopping of the first motor and/or the second motor according to the comparison result output by the comparison module; and

and the suspension control module is used for adjusting the direction and the size of the exciting current in the electromagnet based on the difference value between the distance measured value and the distance set value so as to adjust the magnetic field force between the grabbing part and the object to be grabbed.

Further, the motor control module is used for starting the first motor and/or the second motor to reduce the distance between the grabbing part and the object to be grabbed at a constant speed under the condition that the measured distance value is greater than the corresponding distance set value until the measured distance value is reduced to be less than or equal to the distance set value, and stopping the first motor and the second motor;

the suspension control module is used for adjusting the direction and the size of exciting current in the electromagnet based on the difference value between the distance measured value and the distance set value after the first motor and the second motor stop so as to adjust the magnetic field force between the grabbing part and the object to be grabbed.

The specific definition of each functional module in the above gripping device for permanent magnet and electromagnetic hybrid levitation may refer to the definition of the above gripping method for permanent magnet and electromagnetic hybrid levitation, and is not described herein again. The various modules in the above-described apparatus may be implemented in whole or in part by software, hardware, and combinations thereof. The modules can be embedded in a hardware form or independent from a processor in the computer device, and can also be stored in a memory in the computer device in a software form, so that the processor can call and execute operations corresponding to the modules.

The embodiment of the invention also provides a machine-readable storage medium, which stores instructions for causing a machine to execute the grabbing method of the permanent magnet and electromagnetic hybrid levitation, which is described above.

Example 1

In the capturing method of the permanent-magnet-electromagnetic hybrid suspension provided by this embodiment, the initial constant excitation current provided to the electromagnet 14 is zero, and in the capturing process, a manner of adjusting the distance setting value in real time is adopted, that is, the distance setting value is adjusted in each sampling period, as shown in fig. 1 to 4, which specifically includes:

step one, controlling the initial constant excitation current value provided by the power amplifying circuit 13 to the electromagnet 14 to be zero through the suspension controller 12, not generating electromagnetic force between the electromagnet 14 and the permanent magnet 21, and having permanent magnetic attraction between an iron core in the electromagnet 14 and the permanent magnet 21 of the object 2 to be grabbed;

step two, acquiring a distance measured value between the grabbing part 1 and the object 2 to be grabbed according to preset sampling time through the distance receptor 11, transmitting the acquired distance measured value to the grabbing controller 16, adjusting a distance set value in real time through the set value adjuster 15, and comparing the distance measured value at each preset sampling time with the distance set value corresponding to the preset sampling time by the grabbing controller 16:

if the measured distance value is larger than the corresponding set distance value, starting the first motor 3 and/or the second motor 5 to reduce the distance between the grabbing part 1 and the object 2 to be grabbed at a constant speed (along with the reduction of the distance between the grabbing part 1 and the object 2 to be grabbed, the permanent magnetic attraction between the grabbing part 1 and the object 2 to be grabbed is gradually increased) until the measured distance value is reduced to be smaller than or equal to the set distance value, at this moment, the permanent magnetic attraction on the object 2 to be grabbed is larger than gravity, the object 2 to be grabbed is separated from the tray 7 and is rapidly lifted, and then immediately stopping the first motor 3 and the second motor 5;

and thirdly, the suspension controller 12 generates a corresponding control signal according to a control algorithm based on a difference value between the actual distance measurement value and the distance setting value and transmits the control signal to the power amplifying circuit 13, and the power amplifying circuit 13 adjusts the direction and the magnitude of the exciting current in the electromagnet 14 according to the control signal so as to adjust the magnetic field force between the grabbing part 1 and the object 2 to be grabbed, thereby realizing magnetic suspension grabbing (the electromagnet 14 generates electromagnetic repulsion force to counteract the permanent magnetic attraction force between part of the iron core of the electromagnet 14 and the permanent magnet 21 of the object 2 to be grabbed, so that the force applied to the object 2 to be grabbed is balanced).

In the grabbing process, the specific process of adjusting the distance set value in real time through the set value adjuster 15 is as follows: the set value adjuster 15 reads the distance theoretical value, and updates the distance set value based on the distance theoretical value; the distance theoretical value is a predicted value of the distance between a grabbing part and an object to be grabbed after a plurality of sampling periods (5-20 sampling periods) at the current sampling time.

Specifically, since the distance between the grasping section 1 and the object 2 to be grasped changes at a uniform speed, a subtraction function (y-b-at, where b is an initial value of the distance and a is a rate of change) with the distance as time can be derived, and a predicted value of the distance between the grasping section 1 and the object 2 to be grasped at a sampling time in the future can be calculated as a theoretical value of the distance corresponding to the sampling time by the subtraction function. More specifically, taking the current sampling instant as an example: the distance predicted value after 5 sampling periods can be calculated based on the subtraction function, and the distance predicted value is used as the distance theoretical value of the current sampling time to update the distance set value, so that the distance predicted value corresponding to each sampling time is calculated. For the case that the distance signal is nonlinear, through repeated experiments, a nonlinear subtraction function of distance and time can be established, so that the predicted distance value after a plurality of (5-20) sampling periods is set as a distance theoretical value, and the set distance value is updated.

Fig. 5 is a schematic diagram of a variation relationship between a distance measured value, a distance set value and a current value provided in embodiment 1 of the present invention, and fig. 6 is a schematic diagram of a partial variation relationship between a distance measured value and a distance set value provided in embodiment 1 of the present invention; as shown in fig. 5 to 6, in another embodiment, the distance theoretical value after several sampling cycles is used as the distance setting value of the current sampling time, so as to obtain the distance setting value corresponding to each sampling time.

In another embodiment, the first step further comprises: initializing a distance set value; specifically, the first motor 3 and/or the second motor 5 are/is started while the initial constant excitation current is supplied to the electromagnet 14, so that the distance between the grasping portion 1 and the object 2 to be grasped is reduced at a constant speed, and distance measured values corresponding to a plurality of (3 to 5) sampling moments are continuously acquired by the distance receptor 11, so that a decreasing function of a distance theoretical value along with time is determined, and a distance set value is initialized.

Example 2

In the capturing method of the permanent-magnet-electromagnetic hybrid levitation provided in this embodiment, the initial constant excitation current provided to the electromagnet 14 is zero, and in the capturing process, only one set of distance setting value is set and adjusted according to a preset time interval, that is, the distance setting value is adjusted in the first sampling period of each time interval, as shown in fig. 1 to 4, the method specifically includes:

step one, controlling the initial constant excitation current value provided by the power amplifying circuit 13 to the electromagnet 14 to be zero through the suspension controller 12, not generating electromagnetic force between the electromagnet 14 and the permanent magnet 21, and having permanent magnetic attraction between an iron core in the electromagnet 14 and the permanent magnet 21 of the object 2 to be grabbed;

step two, acquiring a distance measured value between the grabbing part 1 and the object 2 to be grabbed in real time according to a preset sampling time through the distance receptor 11, transmitting the acquired distance measured value to the grabbing controller 16, adjusting a distance set value according to a preset time interval through the set value adjuster 15 (including acquiring a distance calculated value according to the preset time interval; updating the distance set value based on the acquired distance calculated value), and comparing the acquired distance measured value at each preset sampling time with the distance set value corresponding to the preset sampling time through the grabbing controller 16:

if the measured distance value is greater than the corresponding set distance value, the first motor 3 and/or the second motor 5 is/are started to reduce the distance between the grabbing part 1 and the object 2 to be grabbed at a constant speed (along with the reduction of the distance between the grabbing part 1 and the object 2 to be grabbed, the permanent magnetic attraction between the grabbing part 1 and the object 2 to be grabbed is gradually increased) until the measured distance value is reduced to be less than or equal to the set distance value, at this moment, the permanent magnetic attraction on the object 2 to be grabbed is greater than gravity, the object 2 to be grabbed is separated from the tray 7 and is rapidly lifted, and the first motor 3 and the second motor 5 are immediately stopped;

and thirdly, the suspension controller 12 generates a corresponding control signal according to a control algorithm based on a difference value between the actual distance measurement value and the distance setting value and transmits the control signal to the power amplifying circuit 13, and the power amplifying circuit 13 adjusts the direction and the magnitude of the exciting current in the electromagnet 14 according to the control signal so as to adjust the magnetic field force between the grabbing part 1 and the object 2 to be grabbed, thereby realizing magnetic suspension grabbing (the electromagnet 14 generates electromagnetic repulsion force to counteract the permanent magnetic attraction force between part of the iron core of the electromagnet 14 and the permanent magnet 21 of the object 2 to be grabbed, so that the force applied to the object 2 to be grabbed is balanced).

Fig. 7 is a schematic diagram of a variation relationship among a distance measured value, a distance set value, and a current value provided in embodiment 2 of the present invention; fig. 8 is a schematic diagram of a partial variation relationship between the measured distance value and the set distance value provided in embodiment 2 of the present invention, as shown in fig. 7-8; in the grasping process, the specific process of adjusting the distance set value by the set value adjuster 15 according to the preset time interval is as follows:

the method comprises the steps that continuous time intervals can be obtained according to preset time intervals delta T, the length of each time interval is delta T and comprises a plurality of (5-100) sampling periods, each time interval has a corresponding distance calculation value, namely each time interval has a corresponding distance set value, and the distance set value can be adjusted according to the preset time intervals.

Specifically, the distance calculation value corresponding to each time interval can be calculated by the following formula:

wherein i is a natural number and is more than or equal to 3; y is_sp0(t_i) Is t_iCalculating the distance of the moment; y (t)_i) Is t_iA measured value of the distance of the time; y' (t)_i) Is t_iThe time rate of change of the measured distance value at that moment; t is t_i-1＝t_i-ΔT；t_i-2＝t_i-1- Δ T; Δ T is a preset time interval; alpha is a safety coefficient and is more than or equal to 1; beta is a safety constant, and beta<0。

Specifically, at the fourth time interval in FIG. 8 and at the first sample of that time intervalMoment t₄For example. At t₄At the moment, the distance calculation value y corresponding to the time interval needs to be calculated by a formula_sp0(t₄) As the distance setting value for the time interval. Thus, the set value adjuster 15 reads t₄Distance measured value y (t) of time₄)、t₃Distance measured value y (t) of time₃) And t₂Distance measured value y (t) of time₂) And substituting the distance calculation value y into a formula to calculate and obtain a distance calculation value y corresponding to the fourth time interval_sp0(t₄) As t₄A distance set value of the moment; in addition, during this time interval, t is used for the rest of the sampling instants₄And the distance calculation value of the time serves as a corresponding distance set value.

In another embodiment, the first step further comprises: initializing a distance set value; specifically, the first electric machine 3 and/or the second electric machine 5 is started while the initial constant excitation current is supplied to the electromagnet 14; since the formula for calculating the distance calculation value requires distance measured values for three consecutive time intervals, the formula is not applicable to the first two time intervals; generally speaking, the situation that the permanent magnetic attraction force on the object 2 to be grabbed is greater than the gravity does not occur in the first two time intervals, so the distance calculation value can be calculated by applying the following simplified calculation formula:

y_sp0(t_i)＝y(t_i)+β₀(ii) a Wherein, beta₀<<β<0, i ═ 1 or 2.

Example 3

In the capturing method of the permanent-magnet-electromagnetic hybrid suspension provided in this embodiment, the initial constant excitation current provided to the electromagnet 14 is zero, and in the capturing process, two sets of distance setting values are set, including a first distance setting value and a second distance setting value, and are alternately adjusted according to a preset time interval, as shown in fig. 1 to 4, specifically including:

step one, controlling the initial constant excitation current value provided by the power amplifying circuit 13 to the electromagnet 14 to be zero through the suspension controller 12, not generating electromagnetic force between the electromagnet 14 and the permanent magnet 21, and having permanent magnetic attraction between an iron core in the electromagnet 14 and the permanent magnet 21 of the object 2 to be grabbed;

step two, acquiring a distance measured value between the grabbing part 1 and the object 2 to be grabbed according to a preset sampling time through the distance receptor 11, transmitting the acquired distance measured value to the grabbing controller 16, and alternately adjusting a first distance set value and a second distance set value through the set value adjuster 15 according to a preset time interval (including alternately acquiring a first distance calculated value and a second distance calculated value according to the preset time interval, updating the first distance set value based on the acquired first distance calculated value, and updating the second distance set value based on the acquired second distance calculated value), and comparing the distance measured value of each preset sampling time with the distance set value corresponding to the preset sampling time by the grabbing controller 16:

if the distance measured value is greater than the corresponding distance set value (the distance set value is a first distance set value or a second distance set value), starting the first motor 3 and/or the second motor 5 to reduce the distance between the grabbing part 1 and the object 2 to be grabbed at a constant speed (the permanent magnetic attraction between the grabbing part 1 and the object 2 to be grabbed gradually increases along with the reduction of the distance between the grabbing part 1 and the object 2 to be grabbed) until the distance measured value is reduced to be less than or equal to the distance set value (the distance set value is a first distance set value or a second distance set value), at this time, the permanent magnetic attraction on the object 2 to be grabbed is greater than gravity, the object 2 to be grabbed is separated from the tray 7 and is rapidly lifted, and then immediately stopping the first motor 3 and the second motor 5;

thirdly, under the condition that the measured distance value is less than or equal to the first distance set value, the suspension controller 12 generates a corresponding control signal according to a control algorithm based on the difference value between the measured distance value and the first distance set value and transmits the control signal to the power amplifying circuit 13, and the power amplifying circuit 13 adjusts the direction and the magnitude of the exciting current in the electromagnet 14 according to the control signal so as to adjust the magnetic field force between the grabbing part 1 and the object 2 to be grabbed, thereby realizing magnetic suspension grabbing (the electromagnet 14 generates electromagnetic repulsion force to counteract the permanent magnetic attraction force between part of the iron core of the electromagnet 14 and the permanent magnet 21 of the object 2 to be grabbed, so that the force on the object 2 to be grabbed is balanced); or under the condition that the distance measured value is less than or equal to the second distance set value, the levitation controller 12 generates a corresponding control signal according to a control algorithm based on a difference value between the distance measured value and the second distance set value, and transmits the control signal to the power amplifying circuit 13, and the power amplifying circuit 13 adjusts the direction and magnitude of the exciting current in the electromagnet 14 according to the control signal to adjust the magnetic field force between the grasping portion 1 and the object 2 to be grasped, so as to achieve magnetic levitation grasping (the electromagnet 14 generates an electromagnetic repulsive force to counteract the permanent magnetic attraction force between part of the iron core of the electromagnet 14 and the permanent magnet 21 of the object 2 to be grasped, so as to balance the force applied to the object 2 to be grasped).

Fig. 9 is a schematic diagram of a variation relationship among a distance measured value, a distance set value, and a current value provided in embodiment 3 of the present invention; fig. 10 is a schematic diagram of a partial variation relationship between an actual distance measurement value and a distance setting value according to embodiment 3 of the present invention, as shown in fig. 9-10, in fig. 9, the actual distance measurement value is first smaller than the first distance setting value, and therefore, at a subsequent time, the first distance setting value and the second distance setting value are not adjusted any longer, and based on a difference between the first distance setting value and the actual distance measurement value, the direction and magnitude of the exciting current in the electromagnet 14 are actively adjusted to adjust the magnetic field force between the grasping portion 1 and the object 2 to be grasped, so as to achieve magnetic levitation grasping.

In the grabbing process, the specific process of alternately adjusting the first distance set value and the second distance set value by the set value adjuster 15 according to the preset time interval is as follows:

for the convenience of distinguishing, the time interval corresponding to the first distance set value is named as a first time interval, the time interval corresponding to the second distance set value is named as a second time interval, the lengths of the first time interval and the second time interval are both delta T and both comprise a plurality of (5-100) sampling periods, and the adjacent first time interval and second time interval have delta T/2 overlapping parts, so that the first distance set value and the second distance set value are alternately adjusted according to the preset time interval delta T, and the adjustment of the second distance set value is delayed by delta T/2 time from the adjustment of the first distance set value. The first distance calculation value corresponding to each first time interval has a corresponding first distance set value; the second distance calculation value corresponding to each second time interval has a corresponding second distance set value.

Specifically, the first distance calculation value corresponding to each first time interval and the second distance calculation value corresponding to each second time interval can be calculated by the following formulas:

the first distance calculation value is calculated according to the following formula:

wherein i is a natural number and is more than or equal to 3; y is_sp1(t_1,i) Is t_1,iCalculating a first distance value of the moment; y (t)_1,i) Is t_1,iA measured value of the distance of the time; y' (t)_1,i) Is t_1,iThe time rate of change of the measured distance value at that moment; t is t_1,i-1＝t_1,i-ΔT；t_1,i-2＝t_1,i-1- Δ T; Δ T is a preset time interval; alpha is a safety coefficient and is more than or equal to 1; beta is a safety constant, and beta<0。

The second distance calculation value is calculated according to the following formula:

wherein i is a natural number and is more than or equal to 3; y is_sp2(t_2,i) Is t_2,iCalculating a second distance value of the moment; y (t)_2,i) Is t_2,iA measured value of the distance of the time; y' (t)_2,i) Is t_2,iThe time rate of change of the measured distance value at that moment; t is t_2,i＝t_1,i+ΔT/2；t_2,i-1＝t_2,i-ΔT；t_2,i-2＝t_2,i-1- Δ T; Δ T is a preset time interval; alpha is a safety coefficient and is more than or equal to 1; beta is a safety constant, and beta<0。

Specifically, the fourth time interval No. one in FIG. 10 and the first sampling time t in this time interval_1,4For example. At t_1,4At the moment, a first distance calculation value y corresponding to the fourth first time interval needs to be calculated through a formula_sp1(t_1,4) As the first distance setting value of the first time interval. Thus, the set value adjuster 15 reads t_1,4Distance measured value y (t) of time_1,4)、t_1,3Distance measured value y (t) of time_1,3) And t_1,2Distance measured value y (t) of time_1,2) And substituting the calculated value into a formula to calculate a first distance calculated value y corresponding to the fourth first time interval_sp1(t_1,4) As t_1,4A first distance set value of the moment; in addition, in the first time interval, the rest sampling time points continue to use t_1,4And taking the first distance calculation value of the moment as a corresponding first distance set value. From t_1,4After the time passes by delta T/2, the fourth second time interval and the first sampling time T in the time interval come_2,4Wherein, t_2,4＝t_1,4+ Δ T/2; at t_2,4At the moment, a second distance calculation value y corresponding to a fourth second time interval needs to be calculated through a formula_sp2(t_2,4) And the set value is used as the second distance set value of the second time interval. Thus, the set value adjuster 15 reads t_2,4Distance measured value y (t) of time_2,4)、t_2,3Distance measured value y (t) of time_2,3) And t_2,2Distance measured value y (t) of time_2,2) And substituting the calculated value into a formula to calculate a second distance calculated value y corresponding to a fourth second time interval_sp2(t_2,4) As t_2,4A second distance set value of the moment; in addition, in the second time interval, the rest sampling time points continue to use t_2,4And taking the second distance calculation value of the moment as a corresponding second distance set value.

The alternate adjustment mode of the first distance set value and the second distance set value can ensure that the permanent magnetic attraction is larger than the gravity while one distance set value is adjusted, the other distance set value can be reliably reserved, the occurrence of misjudgment or missed judgment is avoided, and the accuracy and the stability of the grabbing process are ensured.

In another embodiment, the first step further comprises: initializing a first distance set value and a second distance set value;specifically, when the first motor 3 and/or the second motor 5 is started while the initial constant excitation current is supplied to the electromagnet 14, since the calculation formulas of the first distance calculation value and the second distance calculation value both require distance measured values of three consecutive time intervals, the calculation formulas are not applicable to the first two time intervals; generally speaking, the situation that the permanent magnetic attraction force on the object 2 to be grabbed is greater than the gravity does not occur in the first two time intervals, so the following simplified calculation formula can be applied to calculate the first distance calculation value: y is_sp1(t_1,i)＝y(t_1,i)+β₀Wherein, β₀<<β<0, i ═ 1 or 2; after delta T/2, the distance calculation value II is obtained by applying the following simplified calculation formula: y is_sp2(t_2,i)＝y(t_2,i)+β₀(ii) a Wherein, beta₀<<β<0, i ═ 1 or 2.

Those skilled in the art will appreciate that all or part of the steps in the method for implementing the above embodiments may be implemented by a program, which is stored in a storage medium and includes several instructions to enable a single chip, a chip, or a processor (processor) to execute all or part of the steps in the method according to the embodiments of the present invention. And the aforementioned storage medium includes: a U-disk, a removable hard disk, a Read-Only Memory (ROM), a Random Access Memory (RAM), a magnetic disk or an optical disk, and other various media capable of storing program codes.

While the embodiments of the present invention have been described in detail with reference to the accompanying drawings, the embodiments of the present invention are not limited to the details of the above embodiments, and various simple modifications can be made to the technical solution of the embodiments of the present invention within the technical idea of the embodiments of the present invention, and the simple modifications are within the scope of the embodiments of the present invention. It should be noted that the various features described in the above embodiments may be combined in any suitable manner without departing from the scope of the invention. In order to avoid unnecessary repetition, the embodiments of the present invention will not be described separately for the various possible combinations.

In addition, any combination of the various embodiments of the present invention is also possible, and the same should be considered as disclosed in the embodiments of the present invention as long as it does not depart from the spirit of the embodiments of the present invention.