CN106842961B - Symmetric hysteresis control method of ultrasonic motor servo control system based on Stop operator - Google Patents

Abstract

The invention relates to a symmetrical hysteresis control method of an ultrasonic motor servo control system based on a Stop operator, which comprises the following steps: providing a base and an ultrasonic motor arranged on the base, wherein an output shaft on one side of the ultrasonic motor is connected with a photoelectric encoder, an output shaft on the other side of the ultrasonic motor is connected with a flywheel inertial load, an output shaft of the flywheel inertial load is connected with a torque sensor through a coupler, and a signal output end of the photoelectric encoder and a signal output end of the torque sensor are respectively connected to a control system; the control system is established on the basis of the stop operator compensation controller, and the stop operator compensation controller takes the minimum identification error as an adjustment function of the stop operator compensation controller, so that better input and output control efficiency is obtained. The invention has the advantages of high control accuracy, simple and compact structure and good use effect.

Description

Symmetrical Hysteresis Control Method of Ultrasonic Motor Servo Control System Based on Stop Operator

technical field

The invention relates to a symmetrical hysteresis control method for an ultrasonic motor servo control system based on a Stop operator.

Background technique

In the design of the existing ultrasonic motor servo control system, when the torque output is in an appropriate state, the hysteresis has symmetry, and there is a certain error in the control of the periodic repetitive signal. In order to improve the following performance, we design an ultrasonic motor servo control system based on stop operator symmetrical compensation control. From the implementation results, we found that the torque-speed relationship of the system is basically linear, so the symmetrical compensation control based on the stop operator can effectively improve the control efficiency of the system, and further reduce the influence of the system on the uncertainty, the torque and speed control of the motor Better dynamic characteristics can be obtained.

SUMMARY OF THE INVENTION

In view of this, the purpose of the present invention is to provide a symmetrical hysteresis control method for ultrasonic motor servo control system based on Stop operator, which not only has high control accuracy, but also has a simple and compact structure and good use effect.

In order to achieve the above object, the present invention adopts the following technical scheme: a symmetrical hysteresis control method for an ultrasonic motor servo control system based on a Stop operator, which is characterized in that, comprising the following steps:

Step S1: provide a base and an ultrasonic motor arranged on the base, one output shaft of the ultrasonic motor is connected with the photoelectric encoder, and the other output shaft is connected with the inertial load of the flywheel, and the inertial load of the flywheel is connected. The output shaft is connected with the torque sensor through a coupling, and the signal output end of the photoelectric encoder and the signal output end of the torque sensor are respectively connected to a control system;

Step S2: the control system is based on the stop operator compensation controller, and the stop operator compensation controller takes the minimum identification error as its adjustment function, so as to obtain better input and output control performance; the control system The dynamic equation of is:

where A _p =-B/J, B _P =J/K _t ＞0, C _P =-1/J; B is the damping coefficient, J is the moment of inertia, K _t is the current factor, and T _f (v) is the friction Resistance torque, T _L is the load torque, U(t) is the output torque of the motor, θ _r (t) is the position signal measured by the photoelectric encoder.

Further, in the step S1, the control system includes an ultrasonic motor drive control circuit, the ultrasonic motor drive control circuit includes a control chip circuit and a drive chip circuit, and the signal output end of the photoelectric encoder is connected to the control chip. The corresponding input end of the circuit is connected, the output end of the control chip circuit is connected with the corresponding input end of the driving chip circuit to drive the driving chip circuit, and the driving frequency adjustment signal output end of the driving chip circuit and The adjustment signal output ends of the driving half-bridge circuit are respectively connected with the corresponding input ends of the ultrasonic motor, and the stop operator compensation controller is arranged in the control chip circuit.

Further, in the step S1, the coupling is an elastic coupling.

Further, in the step S1, the ultrasonic motor, the photoelectric encoder and the torque sensor are respectively fixed on the base via the ultrasonic motor fixing bracket, the photoelectric encoder fixing bracket and the torque sensor fixing bracket.

Further, in the step S2, the hysteresis of the motor torque-speed characteristic has symmetry. In order to reduce the influence caused by this phenomenon and reduce the amount of calculation, the stop operator is used to control it with symmetrical hysteresis compensation: the stop operator The output is a function of its critical value s and the input v(t). The output of the stop operator for the input v(t) ∈ C[0, T] can be expressed as:

E _s [v](0)= _es (v(0))

E _s [v](t)= _es (v(t)-v(t _i )+E _s [v](t _i ))

For t _i <t<t _i+1 and 0≤i≤N-1,

e _s =min(s,max(-s,v))

where 0=t ₀ <t ₁ <...<t _l =T is a partition of T[0,T] such that the function v(t)∈C[0,T],C[0,T] represents the space of continuous functions over [0, T], monotonic over each subinterval [t _i , t _i+1 ];

Under different thresholds s, the output of the stop operator is:

Discretize the above formula, and the output is described by n stop operators, 0=s ₀ <s ₁ <...<s _n =S, that is:

where _ws represents the weight of the density function, i.e.

Due to the Lipschitz continuity, the stop operator E _s is an integrable density function, so the model based on the stop operator is Lipschitz continuous for a given input v(t)∈C[0,T], it can be further obtained that this model is monotonic operator, the weight function is integrable and positive;

When the system is working, the input signal v(t) first passes through the inverse system ψ, and its output enters the symmetric system Φ as a control signal, using feedforward compensation to obtain the mapping between the desired input v(t) and output u(t):

u(t)=Φ[ψ[v]](t)

Based on the initial load curve of the PPI model and the given threshold _{ri and the corresponding weight p i ,} two parameters of the stop operator are obtained: the threshold s _i and the weight _wi ;

Suppose the initial loading curve of the PPI model is expressed as:

where r∈[r ₀ , r _np ] and r ₀ =0, _{n p} is the number of operators p, p is the operator of the PPI model, ri is the threshold of the PPI model; function φ _p : R ^+→ R ⁺ is a convex function and an increasing function. In order to obtain the parameters of the compensator, the initial loading curve φ _s based on the stop operator is defined as:

where φ _s:: R ^+→ R ⁺ is a concave function and an increasing function, n _s is the number of operators, s ∈ [0, s ₀ ], s ₀ is set as a large positive real number, satisfying s ₀ >max( v(t)) to ensure strict monotonicity of the stop operator model;

In order to obtain the weights and thresholds of the stop operator model, the thresholds of the stop operator model and the initial load curve satisfy:

s _i = φ _r (r _i ) (3.16)

φ _s (s _i )=r _i (3.17)

According to any point B(r _k , φ _r ) on the initial load curve of the PPI satisfying equations (3.16) and (3.17), it can always find the corresponding point C(s _k , φ on the initial load curve of the stop operator _s ); the threshold of the stop operator model can be related to the threshold of the PPI model in the following way:

s ₁ =r ₁ p ₀

s ₂ =(r ₂ -r ₁ )p ₁ +r ₂ p ₀

s ₃ =(r ₃ -r ₁ )p ₁ +(r ₃ -r ₂ )p ₂ +r ₃ p ₀

s _n =(rn -r ₁ )p ₁ +(rn -r ₂ ) _{p 2} +...+ _{r n p 0} (3.18)

The stop operator model w _i can be calculated according to (3.17) as:

The system of equations (3.19) includes (n+1) unknown variables, and the number of equations is n, in order to solve the equation (3.19) and obtain the weights w _n , the weights w ₀ should be solved first;

其中

是正实数，可以表示为ξ＝φ_s(s_n+1)；Taking the additional point as (s _n +1, φ _s (s _n +1)) on the initial load curve of the SPI model, by making

in

is a positive real number, which can be expressed as ξ=φ _s (s _n +1);

According to (3.16) and (3.17):

Formulas (3.19) and (3.21):

Equation (3.20) can be expressed as:

w ₀ is derived from (3.22) and (3.23):

Finally, the weights _wi of the stop operator model are easily obtained by solving Equation (3.19).

Compared with the prior art, the present invention has the following beneficial effects: the present invention adopts the ultrasonic motor servo controller controlled by the stop operator symmetrical compensation, the system has significant improvement in the torque speed tracking effect, and the symmetrical compensation control can effectively improve the system The control efficiency is improved, and the influence of the system on the uncertainty is further reduced, the control accuracy is improved, and better dynamic characteristics can be obtained. In addition, the device has reasonable design, simple and compact structure, low manufacturing cost, strong practicability and broad application prospect.

Description of drawings

FIG. 1 is a schematic structural diagram of an embodiment of the present invention.

FIG. 2 is a schematic diagram of a control circuit according to an embodiment of the present invention.

FIG. 3 is a diagram of an open-loop control system of the present invention.

In the picture: 1-Photoelectric encoder, 2-Photoelectric encoder fixing bracket, 3-Ultrasonic motor output shaft, 4-Ultrasonic motor, 5-Ultrasonic motor fixing bracket, 6-Ultrasonic motor output shaft, 7-Flywheel inertia load, 8 - Flywheel inertial load output shaft, 9- elastic coupling, 10- torque sensor, 11- torque sensor fixing bracket, 12- base, 13- control chip circuit, 14- drive chip circuit, 15, 16, 17- photoelectric The A, B, Z phase signals output by the encoder, 18, 19, 20, 21 - the drive frequency adjustment signal generated by the driver chip circuit, 22 - the drive half-bridge circuit adjustment signal generated by the driver chip circuit, 23, 24, 25, 26, 27, 28 - the signal of the drive chip circuit generated by the control chip circuit, 29 - the ultrasonic motor drive control circuit.

Detailed ways

The present invention will be further described below with reference to the accompanying drawings and embodiments.

The invention provides a symmetrical hysteresis control method for an ultrasonic motor servo control system based on a Stop operator, which is characterized by comprising the following steps:

Step S1: Please refer to FIG. 1, provide a base 12 and an ultrasonic motor 4 arranged on the base 12, the output shaft 3 of the ultrasonic motor 4 is connected with the photoelectric encoder 1 on one side, and the output shaft 6 on the other side is connected with the photoelectric encoder 1. The flywheel inertial load 7 is connected, the output shaft 8 of the flywheel inertial load 7 is connected with the torque sensor 10 through the elastic coupling 9, the signal output end of the photoelectric encoder 1, the signal output end of the torque sensor 10 connected to the control system respectively.

The ultrasonic motor 4 , the photoelectric encoder 1 , and the torque sensor 10 are respectively fixed on the base 12 via the ultrasonic motor fixing bracket 5 , the photoelectric encoder fixing bracket 2 , and the torque sensor fixing bracket 11 .

As shown in FIG. 2, the above-mentioned control system includes an ultrasonic motor drive control circuit 29, the ultrasonic motor drive control circuit 29 includes a control chip circuit 13 and a drive chip circuit 14, and the signal output end of the photoelectric encoder 1 is connected to the control chip circuit 14. The corresponding input terminals of the chip circuit 13 are connected, and the output terminals of the control chip circuit 13 are connected to the corresponding input terminals of the driving chip circuit 14 to drive the driving chip circuit 14. The driving of the driving chip circuit 14 The frequency adjustment signal output end and the drive half-bridge circuit adjustment signal output end are respectively connected with the corresponding input ends of the ultrasonic motor 4 . The driving chip circuit 14 generates a driving frequency adjustment signal and a driving half-bridge circuit adjustment signal, and controls the frequency, phase and on-off of the A and B two-phase PWM output by the ultrasonic motor. The start and stop of the ultrasonic motor is controlled by turning on and off the output of the PWM wave; the optimal running state of the motor is adjusted by adjusting the frequency of the output PWM wave and the phase difference between the two phases.

Step S2: the control system is established on the basis of the stop operator compensation controller, and the stop operator compensation controller is set in the control chip circuit; the stop operator compensation controller is based on the smallest identification error. Adjust the function to obtain better input and output control performance; the dynamic equation of the control system is:

where A _p =-B/J, B _P =J/K _t ＞0, C _P =-1/J; B is the damping coefficient, J is the moment of inertia, K _t is the current factor, and T _f (v) is the friction Resistance torque, T _L is the load torque, U(t) is the output torque of the motor, θ _r (t) is the position signal measured by the photoelectric encoder.

When the load torque of the motor is moderate, the hysteresis of the motor torque-speed characteristic is symmetrical. In order to reduce the influence of this phenomenon and reduce the amount of calculation, we use the stop operator to control it with symmetrical hysteresis compensation: the stop operator's hysteresis The output is a function of its critical value s and the input v(t). The output of the stop operator for the input v(t) ∈ C[0, T] can be expressed as:

E _s [v](0)= _es (v(0))

E _s [v](t)= _es (v(t)-v(t _i )+E _s [v](t _i ))

For t _i <t<t _i+1 and 0≤i≤N-1,

e _s =min(s,max(-s,v))

where 0=t ₀ <t ₁ <...<t _l =T is a partition of T[0,T] such that the function v(t)∈C[0,T],C[0,T] represents the space of continuous functions over [0, T], monotonic over each subinterval [t _i , t _i+1 ];

Under different thresholds s, the output of the stop operator is:

Discretize the above formula, and the output is described by n stop operators, 0=s ₀ <s ₁ <...<s _n =S, that is:

where _ws represents the weight of the density function, i.e.

Due to the Lipschitz continuity, the stop operator E _s is an integrable density function, so the model based on the stop operator is Lipschitz continuous for a given input v(t)∈C[0,T], it can be further obtained that this model is monotonic operator, the weight function is integrable and positive;

As shown in Figure 3, when the system is working, the input signal v(t) first passes through the inverse system ψ, and its output enters the symmetric system Φ as a control signal. We use feedforward compensation to obtain the desired input v(t) and output u( t) mapping between:

u(t)=Φ[ψ[v]](t)

Based on the initial load curve of the PPI model and the given threshold ri and the corresponding weight _{pi, two parameters of the stop operator can be obtained: the threshold si and the} weight _wi ;

Suppose the initial loading curve of the PPI model is expressed as:

where r∈[r ₀ , r _np ] and r ₀ =0, _{n p} is the number of operators p, p is the operator of the PPI model, ri is the threshold of the PPI model; function φ _p : R ^+→ R ⁺ is a convex function and an increasing function. In order to obtain the parameters of the compensator, the initial loading curve φ _s based on the stop operator is defined as:

where φ _s:: R ^+→ R ⁺ is a concave function and an increasing function, n _s is the number of operators, s ∈ [0, s ₀ ], s ₀ is set as a large positive real number, satisfying s ₀ >max( v(t)) to ensure strict monotonicity of the stop operator model;

In order to obtain the weights and thresholds of the stop operator model, the thresholds of the stop operator model and the initial load curve satisfy:

s _i = φ _r (r _i ) (3.16)

φ _s (s _i )=r _i (3.17)

According to any point B(r _k , φ _r ) on the initial load curve of the PPI satisfying equations (3.16) and (3.17), it can always find the corresponding point C(s _k , φ on the initial load curve of the stop operator _s ); the threshold of the stop operator model can be related to the threshold of the PPI model in the following way:

s ₁ =r ₁ p ₀

s ₂ =(r ₂ -r ₁ )p ₁ +r ₂ p ₀

s ₃ =(r ₃ -r ₁ )p ₁ +(r ₃ -r ₂ )p ₂ +r ₃ p ₀

s _n =(rn -r ₁ )p ₁ +(rn -r ₂ ) _{p 2} +...+ _{r n p 0} (3.18)

The stop operator model w _i can be calculated according to (3.17) as:

The system of equations (3.19) includes (n+1) unknown variables, and the number of equations is n, in order to solve the equation (3.19) and obtain the weights w _n , the weights w ₀ should be solved first;

其中

是正实数，可以表示为ξ＝φ_s(s_n+1)；For this purpose, an additional point is taken as (s _n +1, φ _s (s _n +1)) on the initial load curve of the SPI model, by making

in

is a positive real number, which can be expressed as ξ=φ _s (s _n +1);

According to (3.16) and (3.17):

Formulas (3.19) and (3.21):

Equation (3.20) can be expressed as:

w ₀ is derived from (3.22) and (3.23):

Finally, the weights _wi of the stop operator model are easily obtained by solving Equation (3.19).

The above descriptions are only preferred embodiments of the present invention, and all equivalent changes and modifications made according to the scope of the patent application of the present invention shall fall within the scope of the present invention.

Claims (1)

1. a symmetrical hysteresis control method of ultrasonic motor servo control system based on Stop operator, is characterized in that, comprises the following steps: Step S1: provide a base and an ultrasonic motor arranged on the base, one output shaft of the ultrasonic motor is connected with the photoelectric encoder, and the other output shaft is connected with the inertial load of the flywheel, and the inertial load of the flywheel is connected. The output shaft is connected with the torque sensor through a coupling, and the signal output end of the photoelectric encoder and the signal output end of the torque sensor are respectively connected to a control system; Step S2: the control system is based on the stop operator compensation controller, and the stop operator compensation controller takes the minimum identification error as its adjustment function, so as to obtain better input and output control performance; the control system The dynamic equation of is:

where A _p =-B/J, B _P =J/K _t ＞0, C _P =-1/J; B is the damping coefficient, J is the moment of inertia, K _t is the current factor, and T _f (v) is the friction Resistance torque, T _L is the load torque, U(t) is the output torque of the motor, θ _r (t) is the position signal measured by the photoelectric encoder; In the step S1, the control system includes an ultrasonic motor drive control circuit, the ultrasonic motor drive control circuit includes a control chip circuit and a drive chip circuit, and the signal output end of the photoelectric encoder corresponds to the control chip circuit. The input end is connected, the output end of the control chip circuit is connected with the corresponding input end of the drive chip circuit to drive the drive chip circuit, the drive frequency adjustment signal output end of the drive chip circuit and the drive half bridge The circuit adjustment signal output ends are respectively connected with the corresponding input ends of the ultrasonic motor, and the stop operator compensation controller is arranged in the control chip circuit In the step S1, the coupling is an elastic coupling; In the step S1, the ultrasonic motor, the photoelectric encoder, and the torque sensor are respectively fixed on the base via the ultrasonic motor fixing bracket, the photoelectric encoder fixing bracket, and the torque sensor fixing bracket; In the step S2, the hysteresis of the motor torque-speed characteristic has symmetry. In order to reduce the influence caused by this phenomenon and reduce the amount of calculation, the stop operator is used to control it with symmetrical hysteresis compensation: the output of the stop operator is the A function of the critical value threshold s and the input v(t), the output of the stop operator for the input v(t) ∈ C[0, T] can be expressed as: E _s [v](0)= _es (v(0)) E _s [v](t)= _es (v(t)-v(t _i )+E _s [v](t _i )) For t _i <t<t _i+1 and 0≤i≤N-1, e _s =min(s,max(-s,v)) where 0=t ₀ <t ₁ <...<t _i =T is a partition of T[0,T] such that the function v(t)∈C[0,T],C[0,T] represents the space of continuous functions over [0, T], monotonic over each subinterval [t _i , t _i+1 ]; Under different thresholds s, the output of the stop operator is:

Discretize the above formula, and the output is described by n stop operators, 0=s ₀ <s ₁ <...<s _n =S, that is, the output of the discretized stop operator is:

where _ws represents the weight of the density function, i.e. Due to the Lipschitz continuity, the stop operator E _s is an integrable density function, so the model based on the stop operator is Lipschitz continuous for a given input v(t)∈C[0,T], it can be further obtained that this model is monotonic operator, the weight function is integrable and positive; When the system is working, the input signal v(t) first passes through the inverse system ψ, and its output enters the symmetric system Φ as a control signal, using feedforward compensation to obtain the mapping between the desired input v(t) and output u(t): u(t)=Φ[ψ[v]](t) Based on the initial load curve of the PPI model and the given threshold _{ri and the corresponding weight p i ,} two parameters of the stop operator are obtained: the threshold s _i and the weight _wi ; Suppose the initial loading curve of the PPI model is expressed as: where r∈[r ₀ , r _np ] and r ₀ =0, _{n p} is the number of operators p, p is the operator of the PPI model, ri is the threshold of the PPI model; function φ _p : R ^+→ R ⁺ is a convex function and an increasing function. In order to obtain the parameters of the compensator, the initial loading curve φ _s based on the stop operator is defined as:

where φ _s: R ^+→ R ⁺ is a concave function and an increasing function, n _s is the number of operators, s∈[0, s ₀ ], s ₀ is set as a large positive real number, satisfying s ₀ >max(v (t)), to ensure the strict monotonicity of the stop operator model; In order to obtain the weights and thresholds of the stop operator model, the thresholds of the stop operator model and the initial load curve satisfy: s _i = φ _r (r _i ) (3.16) φ _s (s _i )=r _i (3.17) According to any point B(r _k , φ _r ) on the initial load curve of the PPI satisfying equations (3.16) and (3.17), it can always find the corresponding point C(s _k , φ on the initial load curve of the stop operator _s ); the threshold of the stop operator model can be related to the threshold of the PPI model in the following way: s ₁ =r ₁ p ₀ s ₂ =(r ₂ -r ₁ )p ₁ +r ₂ p ₀ s ₃ =(r ₃ -r ₁ )p ₁ +(r ₃ -r ₂ )p ₂ +r ₃ p ₀ s _n =(rn -r ₁ )p ₁ +(rn -r ₂ ) _{p 2} +...+ _{r n p 0} (3.18) The stop operator model w _i can be calculated according to (3.17) as: The system of equations (3.19) includes (n+1) unknown variables, and the number of equations is n, in order to solve the equation (3.19) and obtain the weights w _n , the weights w ₀ should be solved first; Taking the additional point as (s _n +1, φ _s (s _n +1)) on the initial load curve of the SPI model, by making

in

is a positive real number, which can be expressed as ξ=φ _s (s _n +1); According to (3.16) and (3.17):

Formulas (3.19) and (3.21):

Equation (3.20) can be expressed as:

w ₀ is derived from (3.22) and (3.23):

Finally, the weights _wi of the stop operator model are easily obtained by solving Equation (3.19).

Images