阅读说明：本技术 一种基于滑模控制的智能手套机针筒电机与机头电机的同步控制方法 (Synchronous control method for needle cylinder motor and handpiece motor of intelligent glove knitting machine based on sliding mode control ) 是由 董辉 董高锋 曾乐襄 金雨芳 于 2019-11-13 设计创作，主要内容包括：本发明公开了一种基于滑模控制的智能手套机针筒电机与机头电机的同步控制方法,包括：获取主电机和从电机两者的实际位置差值的绝对值；若实际位置差值的绝对值与预设位置差值的绝对值相等,则采用速度跟踪控制器控制所述从电机正常运行；否则计算实际位置差值的绝对值与预设位置差值的绝对值两者的差值得到位置误差；根据位置误差和预设位置差值的绝对值计算得到角速度给定值；获取从电机的实际角速度,将实际角速度和角速度给定值的差值作为滑膜控制器的输入值,得到滑膜控制器的输出值用于控制所述从电机的转速,保持主电机和从电机的同步。本发明能够有效控制针筒电机和机头电机同步运动,提升智能手套机的机械稳定性,降低故障率。(The invention discloses a synchronous control method of a needle cylinder motor and a machine head motor of an intelligent glove machine based on sliding mode control, which comprises the following steps: acquiring an absolute value of a difference value of actual positions of a main motor and a slave motor; if the absolute value of the actual position difference is equal to the absolute value of the preset position difference, controlling the slave motor to normally operate by adopting a speed tracking controller; otherwise, calculating the difference between the absolute value of the difference value of the actual position and the absolute value of the difference value of the preset position to obtain a position error; calculating according to the position error and the absolute value of the preset position difference value to obtain an angular speed given value; and acquiring the actual angular speed of the slave motor, taking the difference value between the actual angular speed and the set value of the angular speed as an input value of a slip film controller, and acquiring an output value of the slip film controller to control the rotating speed of the slave motor and keep the synchronization of the master motor and the slave motor. The synchronous control device can effectively control the synchronous motion of the needle cylinder motor and the handpiece motor, improve the mechanical stability of the intelligent glove knitting machine and reduce the failure rate.)

1. A synchronous control method of a needle cylinder motor and a machine head motor of an intelligent glove machine based on sliding mode control is used for controlling the needle cylinder motor and the machine head motor of the intelligent glove machine to move synchronously, one of the needle cylinder motor and the machine head motor serves as a main motor, and the other one serves as a slave motor, and is characterized in that the synchronous control method of the needle cylinder motor and the machine head motor of the intelligent glove machine based on sliding mode control comprises the following steps:

step 1: acquiring an absolute value | x | of a difference value of actual positions of a main motor and a slave motor;

step 2: if the absolute value | x | of the difference value of the actual position and the absolute value | x | of the difference value of the preset position are equal_refIf the I is equal, controlling the slave motor to normally operate by adopting a speed tracking controller; otherwise, calculating the absolute value | x | of the difference value of the actual position and the absolute value | x | of the difference value of the preset position_refThe difference of | obtains the position error e_x；

And step 3: according to the position error e_xAnd absolute value | x of the difference between the preset positions_refI, calculating to obtain given value omega of angular velocity_ref；

And 4, step 4: obtaining the actual angular speed omega of the slave motor, and setting the actual angular speed omega and the angular speed to be a given value omega_refThe difference value is used as an input value of a synovial membrane controller, and an output value of the synovial membrane controller is obtained and used for controlling the rotating speed of the slave motor and keeping the synchronization of the master motor and the slave motor;

the construction of the synovial controller comprises:

A. selecting a state variable:

wherein x is₁、x₂Is a state variable, ω_refFor a given value of angular velocity,being the first derivative of the actual angular velocity omega of the motor,is a state variable x₁The first derivative of (a);

B. and (3) carrying out derivation on the state variables:

wherein J is moment of inertia, p_nIs the pole pair number of the motor, psi_fFlux linkage, T, for the interlinking of permanent magnets and stators in electric machines_LIn order to be the load torque,

C. defining parameters

D. the integral sliding mode surface s selected by the principle of sliding mode control is as follows:

s＝cx₁+x₂

wherein c is a preset positive number, and is obtained by deriving an integral sliding mode surface s:

E. let the mathematical model of the hybrid approach law be as follows:

wherein the parameter k₁More than 0, s is the integral slide film surface, 0 is more than α and less than 1, and the parameter k₂＞0，x₁Is a state variable, f (x) is a continuous function, and the expression of the continuous function f (x) is:

wherein, the parameter delta is more than 0, and e is the base number of the natural logarithm;

F. according to the formula after derivation of the integral sliding mode surface s, the mathematical model of the hybrid approach law and the expression of the continuous function f (x), the expression of the sliding mode controller is obtained as follows:

G. obtaining q-axis current i of the motor_qComprises the following steps:

where t is the sampling time.

2. The synchronous control method of a syringe motor and a handpiece motor of an intelligent glove machine based on sliding mode control as claimed in claim 1, wherein the main motor and the slave motor both adopt a zero d-axis current control strategy;

the basic equation of the voltage of the d-p axis of the motor obtained according to the zero d-axis current control strategy is as follows:

wherein u is_d、u_qD, q-axis voltages, i_d、i_qD and q axis currents, L_d、L_qD, q-axis inductances,. psi_fThe magnetic linkage, R, linking the permanent magnet with the stator in the motor_sIs the stator resistance of the motor, omega_eIs the electrical angular velocity of the rotor of the electrical machine;

the component i of the stator current on the d axis is controlled due to the adoption of a zero d axis current control strategy_dKeeping the current to be zero, converting the stator current of the motor into torque current, and then the torque equation is as follows:

T_e＝1.5p_nψ_fi_q

the motor equation of motion is:

wherein, T_eIs an electromagnetic torque, p_nIs the number of pole pairs, omega, of the motor_nIs the mechanical angular velocity, J is the moment of inertia, B is the viscosity coefficient, T_LIs the load torque.

3. The method for synchronously controlling the syringe motor and the handpiece motor of the intelligent glove machine based on the sliding mode control as claimed in claim 1, wherein the obtaining of the absolute value | x | of the difference value of the actual positions of the master motor and the slave motor comprises:

and acquiring a first numerical value uploaded by an encoder of the main motor, acquiring a second numerical value uploaded by an encoder of the auxiliary motor, calculating a difference value between the first numerical value and the second numerical value, and taking an absolute value of the difference value as an absolute value | x | of an actual position difference value.

4. The synchronous control method for the needle cylinder motor and the handpiece motor of the intelligent glove machine based on sliding mode control as claimed in claim 1, wherein the synchronous control method is characterized in that the synchronous control method is based on the position error e_xAnd absolute value | x of the difference between the preset positions_refI, calculating to obtain given value omega of angular velocity_refThe method comprises the following steps:

error of position e_xAfter proportional gain, the absolute value | x of the difference value between the absolute value | x and the preset position_refAdding | as given value omega of angular velocity_ref。

Technical Field

The application belongs to the technical field of motion control, and particularly relates to a synchronous control method of a needle cylinder motor and a machine head motor of an intelligent glove machine based on sliding mode control.

Background

In recent years, fully automatic glove knitting machines have been widely used, and a new intelligent glove knitting machine adopting a plurality of motor units instead of a gear structure has become a new development direction.

The needle selection function of the intelligent glove knitting machine is mainly that a needle selection bird sheet is jacked up through a needle cylinder pin, and therefore a knitting needle indirectly connected with the needle selection bird sheet is selected. The existing intelligent glove knitting machine is characterized in that when a machine head moves to a set position rapidly, a needle cylinder motor drives a needle cylinder to select knitting needles, the needle cylinder motor can carry out load sudden change due to the fact that a needle selecting bird sheet is jacked up, and meanwhile uncertain factors such as load change and parameter change of the machine head motor can cause that the two motors cannot move synchronously, mechanical collision of the glove knitting machine can be caused to damage the machine, and particularly under the conditions that the machine head and the needle cylinder motor move at a high speed and acceleration and deceleration are frequent. Therefore, a synchronous motion control method is urgently needed to improve the motion consistency of the syringe motor and the handpiece motor.

Disclosure of Invention

An object of the application is to provide a synchronous control method of a needle cylinder motor and a machine head motor of an intelligent glove machine based on sliding mode control, the synchronous motion of the needle cylinder motor and the machine head motor can be effectively controlled, the mechanical stability of the intelligent glove machine is improved, and the failure rate is reduced.

In order to achieve the purpose, the technical scheme adopted by the application is as follows:

a synchronous control method of a needle cylinder motor and a machine head motor of an intelligent glove machine based on sliding mode control is used for controlling the needle cylinder motor and the machine head motor of the intelligent glove machine to synchronously move, one of the needle cylinder motor and the machine head motor serves as a main motor, the other one serves as a slave motor, and the synchronous control method of the needle cylinder motor and the machine head motor of the intelligent glove machine based on sliding mode control comprises the following steps:

step 1: acquiring an absolute value | x | of a difference value of actual positions of a main motor and a slave motor;

step 2: if the absolute value | x | of the difference value of the actual position and the absolute value | x | of the difference value of the preset position are equal_refIf | is equal, speed tracking control is adoptedThe controller controls the slave motor to normally operate; otherwise, calculating the absolute value | x | of the difference value of the actual position and the absolute value | x | of the difference value of the preset position_refThe difference of | obtains the position error e_x；

And step 3: according to the position error e_xAnd absolute value | x of the difference between the preset positions_refI, calculating to obtain given value omega of angular velocity_ref；

And 4, step 4: obtaining the actual angular speed omega of the slave motor, and setting the actual angular speed omega and the angular speed to be a given value omega_refThe difference value is used as an input value of a synovial membrane controller, and an output value of the synovial membrane controller is obtained and used for controlling the rotating speed of the slave motor and keeping the synchronization of the master motor and the slave motor;

the construction of the synovial controller comprises:

A. selecting a state variable:

wherein x is₁、x₂Is a state variable, ω_refFor a given value of angular velocity,

being the first derivative of the actual angular velocity omega of the motor,

is a state variable x₁The first derivative of (a);

B. and (3) carrying out derivation on the state variables:

wherein J is moment of inertia, p_nIs the pole pair number of the motor, psi_fFlux linkage, T, for the interlinking of permanent magnets and stators in electric machines_LIn order to be the load torque,

as second derivative of actual angular velocity omega，

Is a state variable x₂The first derivative of (a) is,

is a current i_qFirst derivative of (i)_qIs the q-axis current of the motor;

C. defining parametersParameter(s)

The standard equation of state expression is obtained as:

D. the integral sliding mode surface s selected by the principle of sliding mode control is as follows:

s＝cx₁+x₂

wherein c is a preset positive number, and is obtained by deriving an integral sliding mode surface s:

E. let the mathematical model of the hybrid approach law be as follows:

wherein the parameter k₁>0, s is the integral slide film surface, 0<α<1, parameter k₂>0，x₁Is a state variable, f (x) is a continuous function, and the expression of the continuous function f (x) is:

wherein the parameter delta is greater than 0, and e is the base number of a natural logarithm;

F. according to the formula after derivation of the integral sliding mode surface s, the mathematical model of the hybrid approach law and the expression of the continuous function f (x), the expression of the sliding mode controller is obtained as follows:

G. obtaining q-axis current i of the motor_qComprises the following steps:

where t is the sampling time.

Preferably, the main motor and the slave motor both adopt a zero d-axis current control strategy;

the basic equation of the voltage of the d-p axis of the motor obtained according to the zero d-axis current control strategy is as follows:

wherein u is_d、u_qD, q-axis voltages, i_d、i_qD and q axis currents, L_d、L_qD, q-axis inductances,. psi_fThe magnetic linkage, R, linking the permanent magnet with the stator in the motor_sIs the stator resistance of the motor, omega_eIs the electrical angular velocity of the rotor of the electrical machine;

the component i of the stator current on the d axis is controlled due to the adoption of a zero d axis current control strategy_dKeeping the current to be zero, converting the stator current of the motor into torque current, and then the torque equation is as follows:

T_e＝1.5p_nψ_fi_q

the motor equation of motion is:

wherein, T_eIs an electromagnetic torque, p_nIs the number of pole pairs, omega, of the motor_nIs the mechanical angular velocity, J is the moment of inertia, B is the viscosity coefficient, T_LIs the load torque.

Preferably, the obtaining an absolute value | x | of a difference between actual positions of the master motor and the slave motor includes:

and acquiring a first numerical value uploaded by an encoder of the main motor, acquiring a second numerical value uploaded by an encoder of the auxiliary motor, calculating a difference value between the first numerical value and the second numerical value, and taking an absolute value of the difference value as an absolute value | x | of an actual position difference value.

Preferably, said error in accordance with position e_xAnd absolute value | x of the difference between the preset positions_refI, calculating to obtain given value omega of angular velocity_refThe method comprises the following steps:

error of position e_xAfter proportional gain, the absolute value | x of the difference value between the absolute value | x and the preset position_refAdding | as given value omega of angular velocity_ref。

Compared with the prior art, the synchronous control method of the needle cylinder motor and the machine head motor of the intelligent glove machine based on sliding mode control has the following beneficial effects:

1. after the machine head motor and the needle cylinder motor synchronously run, the problem that overload and mechanical collision are caused by sudden change of the load of the needle cylinder motor when the needle cylinder thimble of the existing intelligent glove machine is used is solved, the mechanical stability of the intelligent glove machine is improved, and the quality of knitted gloves is greatly improved.

2. The synchronous motion controller adopts a sliding mode control algorithm and has strong robustness to system disturbance.

3. Compared with the traditional PID control, the sliding mode control has the advantages of higher response speed and stronger anti-interference capability.

4. Compared with a sliding mode controller of a single approach law, the sliding mode controller provided by the application can ensure that the time for the system to reach a steady state is short, and the buffeting of the system can be weakened.

Drawings

FIG. 1 is a block flow diagram of a synchronous control method of a motor based on a sliding film control according to the present application;

FIG. 2 is a control schematic of the master and slave motors of the present application;

FIG. 3 is a block diagram of the input and output of the synovial controller of the present application;

fig. 4 is a schematic view of one embodiment of a slip surface and slip control track of the present application.

Detailed Description

The technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the drawings in the embodiments of the present application, and it is obvious that the described embodiments are only a part of the embodiments of the present application, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used in the description of the present application herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

As shown in fig. 1, in one embodiment, a synchronous control method for a syringe motor and a handpiece motor of an intelligent glove machine based on sliding mode control is provided, and is used for controlling the syringe motor and the handpiece motor of the intelligent glove machine to move synchronously, so as to solve the problem that the intelligent glove machine has mechanical collision due to load change.

It should be noted that the motor synchronous control method provided in this embodiment is designed for an intelligent glove knitting machine, but the application scenario is not limited to the intelligent glove knitting machine, and the method is applicable to an occasion where two motors need to be controlled to run synchronously.

With the development of the motor, at present, many motors all adopt permanent magnet synchronous motors, in this embodiment, the master motor and the slave motor adopt permanent magnet synchronous motors, and both the master motor and the slave motor adopt a zero-d-axis current control strategy, so the process of determining the mathematical models of the master motor and the slave motor is as follows:

the basic equation of the voltage of the d-p axis of the motor obtained according to the zero d-axis current control strategy is as follows:

wherein u is_d、u_qD, q-axis voltages, i_d、i_qD and q axis currents, L_d、L_qD, q-axis inductances,. psi_fThe magnetic linkage, R, linking the permanent magnet with the stator in the motor_sIs the stator resistance of the motor, omega_eIs the electrical angular velocity of the rotor of the electrical machine.

The component i of the stator current on the d axis is controlled due to the adoption of a zero d axis current control strategy_dKeeping the current to be zero, converting the stator current of the motor into torque current, and then the torque equation is as follows:

T_e＝1.5p_nψ_fi_q(2)

the motor equation of motion is:

wherein, T_eIs an electromagnetic torque, p_nIs the number of pole pairs, omega, of the motor_nIs the mechanical angular velocity, J is the moment of inertia, B is the viscosity coefficient, T_LIs the load torque.

According to the torque equation and the motor motion equation, the current i on the armature of the motor stator_qAll the magnetic flux is converted into torque current, so that the electromagnetic thrust is changed, and the rotating speed of the motor is changed.

Specifically, the synchronous control method for the syringe motor and the handpiece motor of the intelligent glove machine based on sliding mode control in the embodiment includes:

step 1: and acquiring an absolute value | x | of the difference value of the actual positions of the master motor and the slave motor.

As shown in fig. 2, in this embodiment, the main motor is set to be in normal operation control, that is, the controller outputs a control signal according to a control strategy, the control signal is converted by the D/a converter and then is output to the server, the server controls the motion of the main motor, and the encoder obtains the motion information of the main motor; the slave motor is set as an adjusting motor, and the slave single motor is adjusted to be used as an entry point, so that the adjusting method is simplified.

To determine the position difference, which most directly reflects the position state, is an encoder coupled to the motor, so in one embodiment, obtaining the actual position difference comprises: and acquiring a first numerical value uploaded by an encoder of the main motor, acquiring a second numerical value uploaded by an encoder of the auxiliary motor, calculating a difference value between the first numerical value and the second numerical value, and taking an absolute value of the difference value as an absolute value | x | of an actual position difference value.

The method is simple, and the accuracy of the absolute value | x | of the obtained actual position difference is high.

Step 2: if the absolute value | x | of the difference value of the actual position and the absolute value | x | of the difference value of the preset position are equal_refIf the I is equal, a speed tracking controller is adopted to control the slave motor to normally operate; otherwise, calculating the absolute value | x | of the difference value of the actual position and the absolute value | x | of the difference value of the preset position_refThe difference of | obtains the position error e_x。

When the slave motor is adjusted, the position of the master motor is taken as a target to adjust the position, namely when the master motor and the slave motor synchronously run, a speed tracking controller is adopted to keep the slave motor running normally; when the master motor and the slave motor run asynchronously, the slave motor outputs a control signal from the synovial controller, the control signal is converted by the D/A converter and then is output to the frequency converter, the frequency converter controls the motion of the master motor, the motion information of the master motor is acquired by the encoder, and the speed sensor is adopted to acquire the speed of the slave motor. Absolute value | x of preset position difference_refL is adjusted according to different requirements, e.g. by presetting the absolute value | x of the position difference_refAnd l is the absolute value of the difference value of the optimal positions of a needle cylinder motor and a machine head motor of the current intelligent glove machine, and the difference value is determined by the structure of the intelligent glove machine.

And step 3:according to the position error e_xAnd absolute value | x of the difference between the preset positions_refI, calculating to obtain given value omega of angular velocity_ref。

As shown in FIG. 3, the present embodiment takes the position error e_xAfter proportional gain, the absolute value | x of the difference value between the absolute value | x and the preset position_refAdding | as given value omega of angular velocity_refThe larger the coefficient of the proportional gain, the faster the speed of adjustment, but the proportional gain cannot be increased beyond the range of the natural vibration number of the mechanical system to avoid damage caused by overload operation of the motor.

The present embodiment adopts the position difference value calculation according to owner, the slave motor to obtain the current angular velocity given value of slave motor, rather than adopting fixed angular velocity given value to adjust the slave motor, the adjustment mode of this embodiment is in order to adjust owner, synchronous starting of slave motor position, adopt more direct mode, position difference value between them is the entry point promptly, convert position error into angular velocity, realize the adjustment from the motor, the adjustment process has more pertinence, and effectively alleviateed the phenomenon of adjusting the shock, can be very fast correct the position of slave motor.

And 4, step 4: obtaining the actual angular speed omega of the slave motor, and setting the actual angular speed omega and the angular speed to be a given value omega_refThe difference value is used as an input value of the slip film controller, and an output value of the slip film controller is obtained and used for controlling the rotating speed of the slave motor and keeping the synchronization of the master motor and the slave motor.

The construction of the synovial membrane controller comprises the following steps:

A. selecting a state variable:

wherein x is₁、x₂Is a state variable, ω_refFor a given value of angular velocity,

being the first derivative of the actual angular velocity omega of the motor,

is a state variable x₁The first derivative of (a);

B. to facilitate the design of the synovial controller, the model needs to be simplified, so the state variables are derived without considering the viscosity coefficient B:

wherein J is moment of inertia, p_nIs the pole pair number of the motor, psi_fFlux linkage, T, for the interlinking of permanent magnets and stators in electric machines_LIn order to be the load torque,

being the second derivative of the actual angular velocity omega,

is a state variable x₂The first derivative of (a) is,

is a current i_qFirst derivative of (i)_qIs the q-axis current of the motor.

C. On the basis of the formula (5), parameters are defined

Parameter(s)

The standard equation of state expression is obtained as:

D. the integral sliding mode surface s selected by the principle of sliding mode control is as follows:

s＝cx₁+x₂(7)

wherein c is a preset positive number, usually a given positive number, and is obtained by deriving an integral sliding mode surface s:

E. the sliding mode control introduces an approximation law because the sliding mode control may have a buffeting phenomenon to cause disturbance, and common approximation laws include an exponential approximation law, a power approximation law and a constant velocity approximation law. When | s | is larger, the approach speed of the sliding mode is high; when | s | is small, the approach speed is slow, and therefore the system can be made to accelerate the time to reach the slip-form face while attenuating buffeting. Let the mathematical model of the hybrid approach law be as follows:

wherein the parameter k₁>0, s is the integral slide film surface, 0<α<1, parameter k₂>0，x₁For the state variables, f (x) is a continuous function, f (x) is a switching function in the alternative power approximation law, and the expression of the continuous function f (x) is:

wherein the parameter delta is greater than 0, and e is the base number of a natural logarithm;

F. according to the formula (8) after derivation of the integral sliding mode surface s, the mathematical model formula (9) of the mixed approximation law and the expression formula (10) of the continuous function f (x), the expression of the synovial membrane controller is obtained as follows:

G. obtaining q-axis current i of the motor_qComprises the following steps:

where t is the sampling time.

In the above formula, x₁Variables as inputs, i.e. calculated actual angular velocity ω and given angular velocity ω_refThe difference of (a). Accessibility conditions by sliding mode

Under the action of the controller, the system quickly tends to be stable.

Experiments show that the sliding mode variable structure controller based on the novel mixed approach law reduces the speed-up delay of the PMSM by a half, reduces the speed error by a half, enables the system to have rapidity and strong robustness at the same time, has no overshoot, effectively improves the dynamic quality of the sliding mode controller, facilitates engineering application, and has high practical value.

As shown in fig. 4, which is a sliding mode surface (i.e., a sliding mode switching surface) and a control trajectory under the control of the sliding mode, it can be known from the diagram that a system variable can quickly reach a position of an equilibrium point. The output of the sliding mode controller is the input of the motor current loop because of the motor torque T_eOnly with i_qProportional ratio, when there is disturbance, according to the design idea of the sliding mode controller, calculating the position error of the master motor and the slave motor in real time as the given input of the sliding mode controller, quickly calculating the output value of the sliding mode controller, and outputting a q-axis current instruction to change the electromagnetic thrust F_eAnd further, the rotating speed of the slave motor is changed, and synchronous motion control of the master motor and the slave motor is realized. When the position error e_xWhen the system variable is larger, the system variable can be known to rapidly approach to the equilibrium position from the motion trail of FIG. 4; when the position error is smaller, the approaching speed becomes slower according to the motion track, and the phenomenon of buffeting is prevented.

The technical features of the embodiments described above may be arbitrarily combined, and for the sake of brevity, all possible combinations of the technical features in the embodiments described above are not described, but should be considered as being within the scope of the present specification as long as there is no contradiction between the combinations of the technical features.

The above-mentioned embodiments only express several embodiments of the present application, and the description thereof is more specific and detailed, but not construed as limiting the scope of the invention. It should be noted that, for a person skilled in the art, several variations and modifications can be made without departing from the concept of the present application, which falls within the scope of protection of the present application. Therefore, the protection scope of the present patent shall be subject to the appended claims.