阅读说明：本技术 数字切片扫描仪步进电机加减速的控制方法及装置 (Method and device for controlling acceleration and deceleration of stepping motor of digital slice scanner ) 是由 李世岩 孟庆新 于 2020-12-09 设计创作，主要内容包括：本发明公开了一种数字切片扫描仪步进电机加减速的控制方法及装置,方法包括以下步骤：根据数字切片扫描仪扫描过程中步进电机的最高转速计算出步进电机最高速匀速运动时步与步之间的时间间隔；根据所计算的时间间隔、以及加减速所需要的步数x和时间,计算S型加减速曲线的各个参数；通过S型加减速曲线公式计算出步进电机加速阶段和减速阶段每步之间的时间间隔；根据输入步数的不同,将总步数划分为多个部分；根据划分好的步数,配合步与步之间的时间间隔,控制步进电机的移动。本发明对步进电机的加速和减速控制更加灵活更加精准,对步进电机转动不同步数的时间控制也更加灵活。(The invention discloses a method and a device for controlling acceleration and deceleration of a stepping motor of a digital slice scanner, wherein the method comprises the following steps: calculating the time interval between steps when the stepping motor moves at the highest speed and at the uniform speed according to the highest rotating speed of the stepping motor in the scanning process of the digital slice scanner; calculating each parameter of the S-shaped acceleration and deceleration curve according to the calculated time interval, and the step number x and the time required by acceleration and deceleration; calculating the time interval between each step of the acceleration stage and the deceleration stage of the stepping motor by an S-shaped acceleration and deceleration curve formula; dividing the total step number into a plurality of parts according to different input step numbers; and controlling the movement of the stepping motor according to the divided steps and the time interval between the steps. The invention has more flexible and more accurate control on the acceleration and the deceleration of the stepping motor and more flexible control on the time of rotating the stepping motor by different steps.)

1. A control method for acceleration and deceleration of a stepping motor of a digital slice scanner is characterized by comprising the following steps:

calculating the time interval between steps when the stepping motor moves at the highest speed and at the uniform speed according to the highest rotating speed of the stepping motor in the scanning process of the digital slice scanner;

calculating each parameter of the S-shaped acceleration and deceleration curve according to the calculated time interval, and the step number x and the time required by acceleration and deceleration;

calculating the time interval between each step of the acceleration stage and the deceleration stage of the stepping motor by an S-shaped acceleration and deceleration curve formula;

dividing the total step number into a plurality of parts according to different input step numbers;

and controlling the movement of the stepping motor according to the divided steps and the time interval between the steps.

2. The method for controlling acceleration and deceleration of the stepping motor of the digital slice scanner as claimed in claim 1, wherein the time interval t between steps when the stepping motor moves at the highest speed and at the uniform speed is:

in the formula, m is the rotating speed of the stepping motor, and n is the number of steps of one turn of the stepping motor.

3. The method as claimed in claim 2, wherein the formula of the S-shaped acceleration/deceleration curve is as follows:

where t is the time interval between steps, k is the maximum value of the time interval between steps, a and b are constants, and x is the number of steps at the time of acceleration.

4. The method of claim 3, wherein the dividing the total number of steps into a plurality of portions comprises: according to the difference of the input steps, the total steps are divided into two parts of acceleration steps and deceleration steps, or the total steps are divided into three parts of acceleration steps, constant speed steps and deceleration steps.

5. The method as claimed in claim 4, wherein the dividing the total number of steps into two parts of an acceleration step number and a deceleration step number comprises:

and comparing the number of steps moved by the stepping motor with a set threshold number of steps, and if the number of steps moved by the stepping motor is smaller than or equal to 2 times of the threshold number of steps and is an even number, dividing the total number of steps into a half acceleration step number and a half deceleration step number.

6. The method as claimed in claim 4, wherein the dividing of the total number of steps into three parts, namely, an acceleration step, a constant speed step and a deceleration step, comprises: if the number of moving steps of the stepping motor is less than or equal to 2 times of the threshold number of steps and is an odd number, dividing the total number of steps into 1 step of constant speed, and dividing the rest number of steps into half of the number of acceleration steps and half of the number of deceleration steps; if the number of moving steps of the stepping motor is more than 2 times of the threshold number of steps, the number of acceleration steps and the number of deceleration steps are both equal to the threshold, and the remaining number of steps is the constant speed number of steps.

7. The utility model provides a controlling means of digital section scanner step motor acceleration and deceleration which characterized by includes:

the highest speed interval calculation module is used for calculating the time interval between the steps when the stepping motor moves at the highest speed and at the uniform speed according to the highest rotating speed of the stepping motor in the scanning process of the digital slice scanner;

the curve parameter calculation module is used for calculating each parameter of the S-shaped acceleration and deceleration curve according to the calculated time interval between steps when the stepping motor moves at the highest speed and at a constant speed and the number x and time of the steps required by acceleration and deceleration;

the stage time interval module is used for calculating the time interval between each step of the acceleration stage and each step of the deceleration stage of the stepping motor through an S-shaped acceleration and deceleration curve formula;

the step number dividing module is used for dividing the total step number into a plurality of parts according to different input step numbers;

and the control module is used for controlling the movement of the stepping motor according to the divided steps and the time interval between the steps.

8. The apparatus as claimed in claim 7, wherein the time interval t between steps when the stepping motor moves at the highest speed and at the uniform speed is:

in the formula, m is the rotating speed of the stepping motor, and n is the number of steps of one turn of the stepping motor.

9. The apparatus for controlling acceleration/deceleration of a stepping motor of a digital slice scanner as claimed in claim 7, wherein the formula of the S-shaped acceleration/deceleration curve is:

where t is the time interval between steps, k is the maximum value of the time interval between steps, a and b are constants, and x is the number of steps at the time of acceleration.

10. The apparatus for controlling acceleration and deceleration of a stepping motor of a digital slice scanner as claimed in claim 7, wherein the step number dividing module comprises:

the first step number dividing module is used for dividing the total step number into an acceleration step number and a deceleration step number according to different input step numbers;

or the second step number dividing module is used for dividing the total step number into three parts of an acceleration step number, a constant speed step number and a deceleration step number according to the difference of the input step numbers.

Technical Field

The invention relates to a method and a device for controlling acceleration and deceleration of a stepping motor of a digital slice scanner, belonging to the technical field of stepping motor control.

Background

Digital slice scanners are a technology that organically combines computer technology with conventional optical magnification devices. The whole pathological section or the pathological section at the designated position can be completely scanned and shot by using a stepping motor to drive X, Y, Z to move in three axes.

The step motor realizes the angular displacement by receiving the pulse, and the speed of the pulse frequency directly influences the speed of the rotation of the step motor. The too fast pulse frequency can not be used when the stepping motor is started, the stepping motor can be out of step due to the too fast pulse frequency, and the overshoot phenomenon of the stepping motor can be caused by the sudden stop of the pulse frequency. The start and stop of the stepping motor is a process in which there is an acceleration and a deceleration, i.e., a process in which the pulse frequency is faster and slower. The acceleration and deceleration process of the stepping motor directly influences whether the movement of the stepping motor is accurate, smooth, stable and fluent.

The step motor is accelerated and decelerated too fast to bring larger motor vibration, the step motor is accelerated and decelerated slowly, and although the vibration is reduced, more time is occupied.

Disclosure of Invention

In order to solve the above problems, the present invention provides a method and an apparatus for controlling acceleration and deceleration of a stepping motor of a digital slice scanner, which can flexibly control acceleration and deceleration of the stepping motor.

The technical scheme adopted for solving the technical problems is as follows:

in a first aspect, a method for controlling acceleration and deceleration of a stepping motor of a digital slice scanner provided in an embodiment of the present invention includes the following steps:

calculating the time interval between steps when the stepping motor moves at the highest speed and at the uniform speed according to the highest rotating speed of the stepping motor in the scanning process of the digital slice scanner;

calculating each parameter of the S-shaped acceleration and deceleration curve according to the calculated time interval, and the step number x and the time required by acceleration and deceleration;

calculating the time interval between each step of the acceleration stage and the deceleration stage of the stepping motor by an S-shaped acceleration and deceleration curve formula;

dividing the total step number into a plurality of parts according to different input step numbers;

and controlling the movement of the stepping motor according to the divided steps and the time interval between the steps.

As a possible implementation manner of this embodiment, the time interval t between steps when the stepping motor moves at the highest speed and at the uniform speed is:

in the formula, m is the rotating speed of the stepping motor, and n is the number of steps of one turn of the stepping motor.

As a possible implementation manner of this embodiment, the formula of the S-type acceleration/deceleration curve is:

where t is the time interval between steps, k is the maximum value of the time interval between steps, a and b are constants, and x is the number of steps at the time of acceleration.

As a possible implementation manner of this embodiment, the dividing the total number of steps into a plurality of parts includes: according to the difference of the input steps, the total steps are divided into two parts of acceleration steps and deceleration steps, or the total steps are divided into three parts of acceleration steps, constant speed steps and deceleration steps.

As a possible implementation manner of this embodiment, the dividing the total number of steps into two parts, namely an acceleration step number and a deceleration step number, includes:

and comparing the number of steps moved by the stepping motor with a set threshold number of steps, and if the number of steps moved by the stepping motor is smaller than or equal to 2 times of the threshold number of steps and is an even number, dividing the total number of steps into a half acceleration step number and a half deceleration step number.

As a possible implementation manner of this embodiment, the dividing the total number of steps into three parts, namely an acceleration step number, a uniform speed step number, and a deceleration step number, includes: if the number of moving steps of the stepping motor is less than or equal to 2 times of the threshold number of steps and is an odd number, dividing the total number of steps into 1 step of constant speed, and dividing the rest number of steps into half of the number of acceleration steps and half of the number of deceleration steps; if the number of moving steps of the stepping motor is more than 2 times of the threshold number of steps, the number of acceleration steps and the number of deceleration steps are both equal to the threshold, and the remaining number of steps is the constant speed number of steps.

In a second aspect, an apparatus for controlling acceleration and deceleration of a stepping motor of a digital slice scanner according to an embodiment of the present invention includes:

the highest speed interval calculation module is used for calculating the time interval between the steps when the stepping motor moves at the highest speed and at the uniform speed according to the highest rotating speed of the stepping motor in the scanning process of the digital slice scanner;

the curve parameter calculation module is used for calculating each parameter of the S-shaped acceleration and deceleration curve according to the calculated time interval between steps when the stepping motor moves at the highest speed and at a constant speed and the number x and time of the steps required by acceleration and deceleration;

the stage time interval module is used for calculating the time interval between each step of the acceleration stage and each step of the deceleration stage of the stepping motor through an S-shaped acceleration and deceleration curve formula;

the step number dividing module is used for dividing the total step number into a plurality of parts according to different input step numbers;

and the control module is used for controlling the movement of the stepping motor according to the divided steps and the time interval between the steps.

As a possible implementation manner of this embodiment, the time interval t between steps when the stepping motor moves at the highest speed and at the uniform speed is:

in the formula, m is the rotating speed of the stepping motor, and n is the number of steps of one turn of the stepping motor.

As a possible implementation manner of this embodiment, the formula of the S-type acceleration/deceleration curve is:

where t is the time interval between steps, k is the maximum value of the time interval between steps, a and b are constants, and x is the number of steps at the time of acceleration.

As a possible implementation manner of this embodiment, the step number dividing module includes:

the first step number dividing module is used for dividing the total step number into an acceleration step number and a deceleration step number according to different input step numbers;

or the second step number dividing module is used for dividing the total step number into three parts of an acceleration step number, a constant speed step number and a deceleration step number according to the difference of the input step numbers.

As a possible implementation manner of this embodiment, the dividing the total number of steps into two parts, namely an acceleration step number and a deceleration step number, includes:

and comparing the number of steps moved by the stepping motor with a set threshold number of steps, and if the number of steps moved by the stepping motor is smaller than or equal to 2 times of the threshold number of steps and is an even number, dividing the total number of steps into a half acceleration step number and a half deceleration step number.

As a possible implementation manner of this embodiment, the dividing the total number of steps into three parts, namely an acceleration step number, a uniform speed step number, and a deceleration step number, includes: if the number of moving steps of the stepping motor is less than or equal to 2 times of the threshold number of steps and is an odd number, dividing the total number of steps into 1 step of constant speed, and dividing the rest number of steps into half of the number of acceleration steps and half of the number of deceleration steps; if the number of moving steps of the stepping motor is more than 2 times of the threshold number of steps, the number of acceleration steps and the number of deceleration steps are both equal to the threshold, and the remaining number of steps is the constant speed number of steps.

The technical scheme of the embodiment of the invention has the following beneficial effects:

the invention has more flexible and more accurate control on the acceleration and the deceleration of the stepping motor and more flexible control on the time of rotating the stepping motor by different steps. Compared with other acceleration and deceleration modes of the stepping motor, the invention enables the speed change of the acceleration and deceleration process of the stepping motor to be smoother and the rotation to be smoother.

Description of the drawings:

FIG. 1 is a flow chart illustrating a method of controlling acceleration and deceleration of a stepper motor of a digital slice scanner in accordance with an exemplary embodiment;

FIG. 2 is a schematic diagram of an S-shaped acceleration and deceleration curve (acceleration and deceleration curves) shown in accordance with an exemplary embodiment;

fig. 3 is a block diagram illustrating a control apparatus for acceleration and deceleration of a stepping motor of a digital slice scanner according to an exemplary embodiment.

Detailed Description

The invention is further illustrated by the following examples in conjunction with the accompanying drawings:

in order to clearly explain the technical features of the present invention, the following detailed description of the present invention is provided with reference to the accompanying drawings. The following disclosure provides many different embodiments, or examples, for implementing different features of the invention. To simplify the disclosure of the present invention, the components and arrangements of specific examples are described below. Furthermore, the present invention may repeat reference numerals and/or letters in the various examples. This repetition is for the purpose of simplicity and clarity and does not in itself dictate a relationship between the various embodiments and/or configurations discussed. It should be noted that the components illustrated in the figures are not necessarily drawn to scale. Descriptions of well-known components and processing techniques and procedures are omitted so as to not unnecessarily limit the invention.

Fig. 1 is a flow chart illustrating a method of controlling acceleration and deceleration of a stepper motor of a digital slice scanner according to an exemplary embodiment. As shown in fig. 1, a method for controlling acceleration and deceleration of a stepping motor of a digital slice scanner according to an embodiment of the present invention includes the following steps:

calculating the time interval between steps when the stepping motor moves at the highest speed and at the uniform speed according to the highest rotating speed of the stepping motor in the scanning process of the digital slice scanner;

calculating each parameter of the S-shaped acceleration and deceleration curve according to the calculated time interval, and the step number x and the time required by acceleration and deceleration;

calculating the time interval between each step of the acceleration stage and the deceleration stage of the stepping motor by an S-shaped acceleration and deceleration curve formula;

dividing the total step number into a plurality of parts according to different input step numbers;

and controlling the movement of the stepping motor according to the divided steps and the time interval between the steps.

As a possible implementation manner of this embodiment, the time interval t between steps when the stepping motor moves at the highest speed and at the uniform speed is:

in the formula, m is the rotating speed of the stepping motor, and n is the number of steps of one turn of the stepping motor.

The larger the time interval t between steps is, the slower the stepping motor rotates, whereas the faster the stepping motor rotates, the rotational speed of the stepping motor is changed by changing the time interval between steps of the stepping motor. When the stepping motor receives a pulse signal, the stepping motor rotates by an angle for one step, and the pulse interval is equal to the time interval t between steps. The lower the pulse interval, i.e. the faster the pulse frequency, the faster the stepper motor speed.

As a possible implementation manner of this embodiment, the formula of the S-type acceleration/deceleration curve is:

where t is the step-to-step time interval, k is the maximum value of the step-to-step time interval, a and b are constants, and x is the number of acceleration steps. x is any positive integer

As a possible implementation manner of this embodiment, the dividing the total number of steps into a plurality of parts includes: according to the difference of the input steps, the total steps are divided into two parts of acceleration steps and deceleration steps, or the total steps are divided into three parts of acceleration steps, constant speed steps and deceleration steps.

As a possible implementation manner of this embodiment, the dividing the total number of steps into two parts, namely an acceleration step number and a deceleration step number, includes:

and comparing the number of steps moved by the stepping motor with a set threshold number of steps, and if the number of steps moved by the stepping motor is smaller than or equal to 2 times of the threshold number of steps and is an even number, dividing the total number of steps into a half acceleration step number and a half deceleration step number.

As a possible implementation manner of this embodiment, the dividing the total number of steps into three parts, namely an acceleration step number, a uniform speed step number, and a deceleration step number, includes: if the number of moving steps of the stepping motor is less than or equal to 2 times of the threshold number of steps and is an odd number, dividing the total number of steps into 1 step of constant speed, and dividing the rest number of steps into half of the number of acceleration steps and half of the number of deceleration steps; if the number of moving steps of the stepping motor is more than 2 times of the threshold number of steps, the number of acceleration steps and the number of deceleration steps are both equal to the threshold, and the remaining number of steps is the constant speed number of steps.

In a second aspect, an apparatus for controlling acceleration and deceleration of a stepping motor of a digital slice scanner according to an embodiment of the present invention includes:

the highest speed interval calculation module is used for calculating the time interval between the steps when the stepping motor moves at the highest speed and at the uniform speed according to the highest rotating speed of the stepping motor in the scanning process of the digital slice scanner;

the curve parameter calculation module is used for calculating each parameter of the S-shaped acceleration and deceleration curve according to the calculated time interval between steps when the stepping motor moves at the highest speed and at a constant speed and the number x and time of the steps required by acceleration and deceleration;

the stage time interval module is used for calculating the time interval between each step of the acceleration stage and each step of the deceleration stage of the stepping motor through an S-shaped acceleration and deceleration curve formula;

the step number dividing module is used for dividing the total step number into a plurality of parts according to different input step numbers;

and the control module is used for controlling the movement of the stepping motor according to the divided steps and the time interval between the steps.

As a possible implementation manner of this embodiment, the time interval t between steps when the stepping motor moves at the highest speed and at the uniform speed is:

in the formula, m is the rotating speed of the stepping motor, and n is the number of steps of one turn of the stepping motor.

As a possible implementation manner of this embodiment, as shown in fig. 2, the formula of the S-shaped acceleration/deceleration curve is:

where t is the time interval between steps, k is the maximum value of the time interval between steps, a and b are constants, and x is the number of steps at the time of acceleration.

The horizontal axis represents x and the vertical axis represents t. When x is 1, t is the time interval after the first step (i.e. the first pulse) of the stepping motor. When x is 2, t is the time interval after the second step (i.e., the second pulse) of the stepping motor. By analogy, the number of acceleration steps or the number of deceleration steps needs to be counted by the number of steps, namely x is counted in sequence. k determines the maximum time interval t between steps, i.e. the maximum pulse interval, b determines the speed of the stepping motor changing from static to uniform motion, x represents the step (assuming that acceleration is set to 30 steps, x takes values from 1 to 30 in sequence), a: this value determines what the minimum value of t would be if x were fixed.

As a possible implementation manner of this embodiment, the step number dividing module includes:

the first step number dividing module is used for dividing the total step number into an acceleration step number and a deceleration step number according to different input step numbers;

or the second step number dividing module is used for dividing the total step number into three parts of an acceleration step number, a constant speed step number and a deceleration step number according to the difference of the input step numbers.

As a possible implementation manner of this embodiment, the dividing the total number of steps into two parts, namely an acceleration step number and a deceleration step number, includes:

and comparing the number of steps moved by the stepping motor with a set threshold number of steps, and if the number of steps moved by the stepping motor is smaller than or equal to 2 times of the threshold number of steps and is an even number, dividing the total number of steps into a half acceleration step number and a half deceleration step number.

As a possible implementation manner of this embodiment, the dividing the total number of steps into three parts, namely an acceleration step number, a uniform speed step number, and a deceleration step number, includes: if the number of moving steps of the stepping motor is less than or equal to 2 times of the threshold number of steps and is an odd number, dividing the total number of steps into 1 step of constant speed, and dividing the rest number of steps into half of the number of acceleration steps and half of the number of deceleration steps; if the number of moving steps of the stepping motor is more than 2 times of the threshold number of steps, the number of acceleration steps and the number of deceleration steps are both equal to the threshold, and the remaining number of steps is the constant speed number of steps.

One specific implementation process for controlling the acceleration and deceleration of the stepping motor of the digital slice scanner by using the control device disclosed by the invention is as follows:

according to the performance of the actual stepping motor and the requirements on the stepping motor in actual use, the rotating speed of the X-axis stepping motor is required to be 236 revolutions per minute, one circle of the X-axis stepping motor is 3200 steps, and the time interval t between the steps of the X-axis highest-speed and uniform-speed motion can be calculated to be 79 microseconds.

In order to reduce the vibration condition of starting and stopping the stepping motor and consider the time control of the movement of the stepping motor, the value of the acceleration and deceleration step number is x which is equal to 50. The initial time interval from the first step to the second step is set to k 300 microseconds.

Through the determination of the above parameters, it can be known that x takes a value from 1 to 50 steps, and t should take a value from 300 to 79 microseconds. That is, the stepping motor is accelerated from the first step to the fiftieth step, and the time interval between each step is smaller and smaller until the time interval t between the steps is 79 microseconds when the highest speed uniform motion is set. The values of the parameters a and b in the sigmoidal equation are then set empirically to meet the above requirements.

And after the S-shaped curve formula is determined, calculating time interval data corresponding to the S-shaped curve according to the S-shaped curve formula and storing the time interval data into an array A. The time interval data directly control the speed of the frequency of the rotation pulse transmission of the stepping motor.

Comparing the number of steps moved by the stepping motor with a set threshold step number (the acceleration step number x is 50), and dividing the number of steps moved by the stepping motor into half for acceleration and half for deceleration if the number of steps moved by the stepping motor is less than or equal to 2 times the threshold step number and is an even number; if the moving step number of the stepping motor is less than or equal to 2 times of the threshold step number and is an odd number, dividing the moving step number into 1 step, namely accelerating half and decelerating half of the residual step number at constant speed; if the number of moving steps of the stepping motor is more than 2 times of the threshold number of steps, the number of acceleration steps is equal to the number of deceleration steps which is equal to the threshold, and the number of residual steps is equal to the number of constant speed steps.

And after the moving steps of the stepping motor are divided, starting to execute an acceleration function, reading the generated pulse frequency from the array A, and reversely executing the deceleration curve, namely the acceleration curve.

As will be appreciated by one skilled in the art, embodiments of the present application may be provided as a method, system, or computer program product. Accordingly, the present application may take the form of an entirely hardware embodiment, an entirely software embodiment or an embodiment combining software and hardware aspects. Furthermore, the present application may take the form of a computer program product embodied on one or more computer-usable storage media (including, but not limited to, disk storage, CD-ROM, optical storage, and the like) having computer-usable program code embodied therein.

In the embodiments provided in the present application, it should be understood that the disclosed apparatus and method may be implemented in other ways. The above-described embodiments of the apparatus are merely illustrative, and for example, a division of modules is merely a division of logical functions, and an actual implementation may have another division, and for example, a plurality of modules or components may be combined or integrated into another system, or some features may be omitted, or not executed. In addition, the shown or discussed mutual coupling or direct coupling or communication connection may be an indirect coupling or communication connection of devices or modules through some communication interfaces, and may be in an electrical, mechanical or other form.

Modules described as separate parts may or may not be physically separate, and parts displayed as modules may or may not be physical modules, may be located in one place, or may be distributed on a plurality of network modules. Some or all of the modules may be selected according to actual needs to achieve the purpose of the solution of the present embodiment.

In addition, functional modules in the embodiments provided in the present application may be integrated into one processing module, or each module may exist alone physically, or two or more modules are integrated into one module.

The present application is described with reference to flowchart illustrations and/or block diagrams of methods, apparatus (systems), and computer program products according to embodiments of the application. It will be understood that each flow and/or block of the flow diagrams and/or block diagrams, and combinations of flows and/or blocks in the flow diagrams and/or block diagrams, can be implemented by computer program instructions. These computer program instructions may be provided to a processor of a general purpose computer, special purpose computer, embedded processor, or other programmable data processing apparatus to produce a machine, such that the instructions, which execute via the processor of the computer or other programmable data processing apparatus, create means for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be stored in a computer-readable memory that can direct a computer or other programmable data processing apparatus to function in a particular manner, such that the instructions stored in the computer-readable memory produce an article of manufacture including instruction means which implement the function specified in the flowchart flow or flows and/or block diagram block or blocks.

These computer program instructions may also be loaded onto a computer or other programmable data processing apparatus to cause a series of operational steps to be performed on the computer or other programmable apparatus to produce a computer implemented process such that the instructions which execute on the computer or other programmable apparatus provide steps for implementing the functions specified in the flowchart flow or flows and/or block diagram block or blocks.

Finally, it should be noted that: the above embodiments are only for illustrating the technical solutions of the present invention and not for limiting the same, and although the present invention is described in detail with reference to the above embodiments, those of ordinary skill in the art should understand that: modifications and equivalents may be made to the embodiments of the invention without departing from the spirit and scope of the invention, which is to be covered by the claims.