RGV dual motor speed synchronization deviation coupling control method and system

Abstract

The present invention relates to a RGV dual motor speed synchronization deviation coupling control method and system, including: generating an S-shaped speed curve; subtracting the instantaneous speed value on the S-shaped speed curve from the collected RGV overall speed value to obtain an error value; inputting the error value into a PID controller function module to obtain an output value of the PID controller; obtaining a speed error value and a speed change rate error value according to the speed values ​​and speed value change rates of driving wheels one and two; obtaining a sliding mode speed compensator output value according to the speed error value and the speed change rate error value; obtaining the preliminary speed of driving wheels one and two according to the output value of the PID controller and the corresponding instantaneous speed value on the S-shaped speed curve and the output value of the sliding mode speed compensator, and obtaining the final speed of driving wheels one and two after correction. The present invention solves the problem of low running stability and accuracy of closed-loop speed control due to insufficient dual motor speed synchronization rate caused by disturbance.

Description

Technical Field

[0001] The present invention relates to the technical field of RGV drive control, and in particular to a RGV dual-motor speed synchronization deviation coupling control method and system. Background Art

[0002] Rail Guide Vehicle (RGV) is an automated rail transport device equipped with non-contact guidance devices such as electromagnetic or optical. It is used for fixed routes, heavy-load transfer and industrial production lines with complex environments due to its large load capacity, safety, reliability and strong environmental adaptability. It has the characteristics of fast and stable operation, high reliability and low cost, and has been increasingly widely used in the field of modern automated logistics systems. RGV can be used as a peripheral device for stereoscopic warehouses or as an independent system.

[0003] In order to meet the stability requirements of material transportation equipment in industrial production, improve production efficiency under variable working distances, and increase the service life of transportation equipment, an S-shaped speed curve is usually used to set the speed of the RGV trolley. Commonly used RGV trolleys include single-wheel single-motor drive forms, or dual-wheel dual-motor drive forms, that is, the two drive wheels are driven by independent drive systems. For the dual-wheel dual-motor drive RGV, the actual working process only relies on the S-shaped speed curve to give the speed value to the inverter for speed control. The system has poor resistance to disturbances, and it is easy to have a speed difference between the motors, which makes it difficult to meet the smoothness and accuracy requirements of the transportation work. Therefore, closed-loop control with dual motor speed synchronization is required.

[0004] Traditional dual-motor synchronous control usually adopts a master-slave control structure or a deviation coupling control structure with a fixed weight speed compensator or a PID speed compensator. Among them, the master-slave control structure has an unavoidable problem of inter-motor command delay due to structural defects. The deviation coupling control with a fixed weight speed compensator or a PID speed compensator is not robust and adaptable enough to unpredictable and high-frequency disturbances, and cannot provide higher stability for the system in a long-term and extensive manner. The defects of these traditional methods will lead to insufficient smoothness of RGV operation, and ultimately affect the accuracy and service life of RGV operation. Summary of the invention

[0005] In view of the shortcomings of the prior art, the present invention provides an RGV dual-motor speed synchronization deviation coupling control method and system, which solves the problem of low closed-loop speed control operation smoothness and accuracy caused by insufficient dual-motor speed synchronization rate caused by disturbances in RGV equipment driven by dual motors.

[0006] The technical solution adopted by the present invention is as follows:

[0007] The present invention provides a RGV dual-motor speed synchronization deviation coupling control method, comprising:

[0008] S1. Calculate intermediate parameters of an S-shaped speed curve according to expected operating parameters of the RGV to generate an S-shaped speed curve for providing a reference speed value; the S-shaped speed curve has a reference time as a horizontal coordinate and a speed value as a vertical coordinate;

[0009] S2, subtract the instantaneous speed value on the S-shaped speed curve from the collected RGV overall speed value to obtain an error value; input the error value into the PID controller function module according to the set time period, and obtain the output value of the PID controller as follows:

[0010] Δu x =K p *(e x -e x-1 )+K i *e x +K d *(e x -2*e x-1 +e x-2 );

[0011] Among them, Δu x is the output value of the PID controller at time x, K p , K i , K d are the P, I, and D parameters of the PID controller, respectively; e represents the input error value; the subscripts x, x-1, and x-2 represent the x moment, x-1 moment, and x-2 moment, respectively; and the difference between adjacent moments is the set time period;

[0012] S3, subtracting the collected speed value of the motor system 1 from the speed value of the motor system 2 to obtain a speed error value; subtracting the collected change rate of the speed value of the motor system 1 from the change rate of the speed value of the motor system 2 to obtain a speed change rate error value;

[0013] The speed error value and the speed change rate error value are input into the sliding mode speed compensator function module to obtain the output value of the sliding mode speed compensator as follows:

[0014]

[0015] Among them, u c is the output value of the sliding mode speed compensator, x 1 is the speed error value, x 2 is the speed change rate error value, β, q, p, ε, τ are design parameters, where β, ε, τ>0, p and q are two positive odd numbers and satisfy The sliding surface s is designed as:

[0016]

[0017] Among them, sat(s) is the saturation function, which is defined as follows:

[0018]

[0019] Δ is a positive real number;

[0020] The motor system 1 includes a driving wheel 1, a driving wheel motor 1 and a frequency converter 1;

[0021] The second motor system comprises a second driving wheel, a second driving wheel motor and a second frequency converter;

[0022] The state space equations of the motor system 1 and the motor system 2 are the same, and the sliding mode speed compensator function module is designed for the state space equations, which are:

[0023]

[0024] Among them, x 1 is the speed error value, x 2 is the speed change rate error value, For x 1 The rate of change, For x 2 The rate of change, u c is the output value of the sliding mode compensator;

[0025] S4, adding the output value of the PID controller to the corresponding instantaneous speed value on the S-shaped speed curve, and then subtracting the output value of the sliding mode speed compensator to obtain the preliminary speed of the driving wheel 1, and adding the preliminary speed of the driving wheel 1 to the first correction value to obtain the final speed of the driving wheel 1;

[0026] The output value of the PID controller is added to the corresponding instantaneous speed value on the S-shaped speed curve, and then the output value of the sliding mode speed compensator is added to obtain the preliminary speed of the second driving wheel, and the preliminary speed value of the second driving wheel is added to the second correction value to obtain the final speed of the second driving wheel;

[0027] The first correction value and the second correction value are respectively the speed change values ​​reflected by considering the influence of external random disturbance on RGV;

[0028] S5. Transmit the final speed of the driving wheel 1 to the frequency converter 1, and transmit the final speed of the driving wheel 2 to the frequency converter 2.

[0029] Further technical solutions are:

[0030] In step S1, a subroutine preset in the PLC controller of the RGV is used to generate an S-shaped speed curve. During the generation of the S-shaped speed curve, the internal reference time of the subroutine is calculated by counting the constant interrupt time. The corresponding instantaneous speed value is calculated in the subroutine by the reference time value, and the voltage signal is output to the inverter 1 and the inverter 2 through the analog output port after linear transformation.

[0031] In step S2, the collection of the RGV overall speed value includes: collecting the overall movement distance of the RGV movement at a constant time difference through the overall speed encoder, and the PLC controller calculates the real-time overall speed based on the collection interruption time of the overall speed encoder.

[0032] In step S3, the encoder of the driving wheel motor 1 and the encoder of the driving wheel motor 2 respectively collect corresponding rotation scales at a constant time difference, and the PLC controller calculates the speed value and the speed value change rate of the motor system 1 based on the collection interruption time of the encoder of the driving wheel motor 1, and calculates the speed value and the speed value change rate of the motor system 2 based on the collection interruption time of the encoder of the driving wheel motor 2.

[0033] The expected operating parameters include the expected displacement, initial and final speeds, maximum speed, maximum acceleration, and maximum jerk of the RGV.

[0034] The present invention also provides an RGV dual-motor speed synchronization deviation coupling control system, comprising:

[0035] An S-shaped speed curve generating module, which calculates intermediate parameters of the S-shaped speed curve according to expected operating parameters of the RGV, and generates an S-shaped speed curve for providing a reference speed value; the S-shaped speed curve has a reference time as a horizontal coordinate and a speed value as a vertical coordinate;

[0036] The PID controller output value calculation module subtracts the instantaneous speed value on the S-shaped speed curve from the collected RGV overall speed value to obtain an error value; the error value is input into the PID controller function module according to the set time period, and the output value of the PID controller is obtained as follows:

[0037] Δu x =K p *(e x -e x-1 )+K i *e x +K d *(e x -2*e x-1 +e x-2 )

[0038] Among them, Δu x is the output value of the PID controller at time x, Kp , K i , K d are the P, I, and D parameters of the PID controller, respectively; e represents the input error value; the subscripts x, x-1, and x-2 represent the x moment, x-1 moment, and x-2 moment, respectively; and the difference between adjacent moments is the set time period;

[0039] The sliding mode speed compensator output value calculation module subtracts the collected motor system 1 speed value and the motor system 2 speed value to obtain a speed error value; subtracts the collected motor system 1 speed value change rate and the motor system 2 speed value change rate to obtain a speed change rate error value; the speed error value and the speed change rate error value are input into the sliding mode speed compensator function module to obtain the output value of the sliding mode speed compensator as follows:

[0040]

[0041] Among them, u c is the output value of the sliding mode speed compensator, x 1 is the speed error value, x 2 is the speed change rate error value, β, q, p, ε, τ are design parameters, where β, ε, τ>0, p and q are two positive odd numbers and satisfy The sliding surface s is designed as:

[0042]

[0043] Among them, sat(s) is the saturation function, which is defined as follows:

[0044]

[0045] Δ is a positive real number;

[0046] The motor system 1 includes a driving wheel 1, a driving wheel motor 1 and a frequency converter 1;

[0047] The second motor system comprises a second driving wheel, a second driving wheel motor and a second frequency converter;

[0048] The state space equations of the motor system 1 and the motor system 2 are the same, and the sliding mode speed compensator function module is designed for the state space equations, which are:

[0049]

[0050] Among them, x 1 is the speed error value, x 2 is the speed change rate error value, For x 1 The rate of change, For x2 The rate of change, u c is the output value of the sliding mode compensator;

[0051] a final speed value calculation module, which adds the output value of the PID controller to the corresponding instantaneous speed value on the S-shaped speed curve, and then subtracts the output value of the sliding mode speed compensator to obtain the preliminary speed of the driving wheel one, and adds the preliminary speed of the driving wheel one to the first correction value to obtain the final speed of the driving wheel one; adds the output value of the PID controller to the corresponding instantaneous speed value on the S-shaped speed curve, and then adds the output value of the sliding mode speed compensator to obtain the preliminary speed of the driving wheel two, and adds the preliminary speed value of the driving wheel two to the second correction value to obtain the final speed of the driving wheel two;

[0052] The first correction value and the second correction value are respectively the speed change values ​​reflected by considering the influence of external random disturbance on RGV;

[0053] An output module transmits the final speed of the driving wheel 1 to the frequency converter 1, and transmits the final speed of the driving wheel 2 to the frequency converter 2.

[0054] Further technical solutions are:

[0055] The S-shaped speed curve generation module uses a subroutine preset in the PLC controller of the RGV to generate an S-shaped speed curve. During the S-shaped speed curve generation process, the internal reference time of the subroutine is calculated by counting the constant interrupt time, and the corresponding instantaneous speed value is calculated in the subroutine by the reference time value, and the voltage signal is output to the inverter 1 and the inverter 2 through the analog output port after linear transformation.

[0056] The acquisition of the RGV overall speed value includes: acquiring the overall movement distance of the RGV movement at a constant time difference through an overall speed encoder, and the PLC controller calculates the real-time overall speed based on the acquisition interruption time of the overall speed encoder.

[0057] The encoder of the driving wheel motor 1 and the encoder of the driving wheel motor 2 respectively collect corresponding rotation scales at a constant time difference. The PLC controller calculates the speed value and the speed value change rate of the motor system 1 based on the collection interruption time of the encoder of the driving wheel motor 1, and calculates the speed value and the speed value change rate of the motor system 2 based on the collection interruption time of the encoder of the driving wheel motor 2.

[0058] The expected operating parameters include the expected displacement, initial and final speeds, maximum speed, maximum acceleration, and maximum jerk of the RGV.

[0059] The beneficial effects of the present invention are as follows:

[0060] The present invention provides a given speed through a preset S-shaped speed curve, and performs overall closed-loop control by feeding back the overall speed of the RGV movement through an overall speed encoder; the speeds of the two driving motors are fed back by a driving wheel motor encoder to obtain the speed value error and the speed value change rate error, and the dual-motor speed synchronization deviation coupling control is completed through a sliding mode speed compensator, which solves the problem of low closed-loop speed control operation smoothness and accuracy caused by insufficient dual-motor speed synchronization rate caused by disturbances in the dual-motor driven RGV equipment, and meets actual production needs.

[0061] Other features and advantages of the present invention will be set forth in the following description or may be learned by practicing the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0062] Figure 1 Schematic diagram of the process of the embodiment of the present invention.

[0063] Figure 2 Schematic diagram of the structure of a dual-motor driven RGV according to an embodiment of the present invention.

[0064] Figure 3 The figure is a control logic diagram of a control system according to an embodiment of the present invention.

[0065] Figure 4 This is a simulation result diagram of the control group in the verification example of the present invention.

[0066] Figure 5 This is a simulation result diagram of the test group in the verification example of the present invention. DETAILED DESCRIPTION

[0067] The specific implementation of the present invention is described below with reference to the accompanying drawings.

[0068] Example 1

[0069] The RGV dual motor speed synchronization deviation coupling control method of this embodiment is used to control the RGV with dual drive wheel and dual motor structure. Figure 2 The RGV with dual driving wheel and dual motor structure includes a PLC controller, a motor system 1, a motor system 2, a driving wheel motor 1 encoder (i.e., the driving wheel motor 1 encoder in the figure), a driving wheel motor 2 encoder (i.e., the driving wheel motor 2 encoder in the figure), and an overall speed encoder.

[0070] The motor system 1 includes a driving wheel 1, a driving wheel motor 1 (i.e., the driving wheel motor 2 in the figure) and a frequency converter 1 (i.e., the frequency converter 1 in the figure); the motor system 2 includes a driving wheel 2, a driving wheel motor 2 (i.e., the driving wheel motor 2 in the figure) and a frequency converter 2 (i.e., the frequency converter 2 in the figure).

[0071] Among them, the encoder of driving wheel motor 1 and the encoder of driving wheel motor 2 are respectively installed on the two driving wheel axles to collect the rotation speed of the two driving wheel motors. The overall speed encoder is installed on the lower side of the RGV body, a driven wheel close to the track, to collect the overall running speed of the RGV. The encoder of driving wheel motor 1, the encoder of driving wheel motor 2 and the overall speed encoder are connected to the PLC controller to transmit data to the PLC controller. Inverter 1 and inverter 2 receive the instructions of the PLC controller by receiving the voltage signal output by the analog output module of the PLC controller. Inverter 1 is connected to driving wheel motor 1, and inverter 2 is connected to driving wheel motor 2. The motor is controlled according to the control logic to control the running speed of the RGV.

[0072] Among them, the speed acquisition of the dual motors comes from the encoder of the driving wheel motor 1 and the encoder of the driving wheel motor 2, which are input through the high-speed pulse counter port of the PLC controller, and the returned signal is calculated by the relevant formula to obtain the instantaneous speed. The PLC controller uses the sliding mode control method to process the error between the actual motion of the motor system 1 and the motor system 2 to obtain the output value of the sliding mode control speed compensator. The feedback for the overall speed of the RGV comes from the overall speed encoder, which is input through the high-speed pulse counter port of the PLC, and the returned signal is calculated by the relevant formula to obtain the instantaneous speed.

[0073] See also Figure 1 The RGV dual motor speed synchronization deviation coupling control method comprises the following steps:

[0074] S1. Calculate intermediate parameters of an S-shaped speed curve according to expected operating parameters of the RGV, and generate an S-shaped speed curve for providing a reference speed value; the S-shaped speed curve uses a reference time as a horizontal coordinate and a speed value as a vertical coordinate.

[0075] Among them, a subroutine preset in the PLC controller of RGV is used to generate an S-shaped speed curve. During the generation of the S-shaped speed curve, the internal reference time of the subroutine is calculated by counting the constant interrupt time. The corresponding instantaneous speed value is calculated in the subroutine by the reference time value, and the voltage signal is output to inverter one and inverter two through the analog output port after linear transformation.

[0076] The expected operating parameters include the expected displacement, initial and final speeds, maximum speed, maximum acceleration, and maximum jerk of the RGV.

[0077] S2. Subtract the instantaneous speed value on the S-shaped speed curve from the collected RGV overall speed value to obtain an error value; input the error value into the PID controller function module according to the set time period, and obtain the output value of the PID controller as follows:

[0078] Δu x=K p *(e x -e x-1 )+K i *e x +K d *(e x -2*e x-1 +e x-2 )

[0079] Among them, Δu x is the output value of the PID controller at time x, K p , K i , K d are the P, I, and D parameters of the PID controller respectively, e represents the input error value, the subscripts x, x-1, and x-2 represent the x moment, x-1 moment, and x-2 moment respectively, and the difference between adjacent moments is the set time period.

[0080] The acquisition of the overall speed value of the RGV includes: acquiring the overall movement distance of the RGV at a constant time difference through an overall speed encoder, and the PLC controller calculates the real-time overall speed based on the acquisition interruption time of the overall speed encoder.

[0081] S3, subtracting the collected speed value of the motor system 1 from the speed value of the motor system 2 to obtain a speed error value; subtracting the collected change rate of the speed value of the motor system 1 from the change rate of the speed value of the motor system 2 to obtain a speed change rate error value;

[0082] The speed error value and the speed change rate error value are input into the sliding mode speed compensator function module to obtain the output value of the sliding mode speed compensator as follows:

[0083]

[0084] Among them, u c is the output value of the sliding mode speed compensator, x 1 is the speed error value, x 2 is the speed change rate error value, β, q, p, ε, τ are design parameters, where β, ε, τ>0, p and q are two positive odd numbers and satisfy The sliding surface s is designed as:

[0085]

[0086] Among them, sat(s) is the saturation function, which is defined as follows:

[0087]

[0088] Δ is a very small positive real number.

[0089] Among them, it can be understood that the motor system one / two speed value refers to the travel speed of the drive wheel one / two;

[0090] The state space equations of the motor system 1 and the motor system 2 are the same, and the sliding mode speed compensator function module is designed for the state space equations, which are:

[0091]

[0092] Among them, x 1 is the speed error value, x 2 is the speed change rate error value, For x 1 The rate of change, For x 2 The rate of change, u c is the output value of the sliding mode compensator;

[0093] Among them, the encoder of the driving wheel motor 1 and the encoder of the driving wheel motor 2 respectively collect corresponding rotation scales at a constant time difference, and the PLC controller calculates the speed value and the speed value change rate of the motor system 1 based on the collection interruption time of the encoder of the driving wheel motor 1, and calculates the speed value and the speed value change rate of the motor system 2 based on the collection interruption time of the encoder of the driving wheel motor 2.

[0094] S4, adding the output value of the PID controller to the corresponding instantaneous speed value on the S-shaped speed curve, and then subtracting the output value of the sliding mode speed compensator to obtain the preliminary speed of the driving wheel 1, and adding the preliminary speed of the driving wheel 1 to the first correction value to obtain the final speed of the driving wheel 1;

[0095] The output value of the PID controller is added to the corresponding instantaneous speed value on the S-shaped speed curve, and then the output value of the sliding mode speed compensator is added to obtain the preliminary speed of the second driving wheel, and the preliminary speed value of the second driving wheel is added to the second correction value to obtain the final speed of the second driving wheel;

[0096] The first correction value and the second correction value are respectively the speed change values ​​reflected by considering the influence of external random disturbance on RGV;

[0097] S5. The final speed of the driving wheel one is transmitted to the inverter one, and the final speed of the driving wheel two is transmitted to the inverter two. The two inverters control the corresponding driving wheel motors according to the final speeds respectively to realize dual-motor RVG control.

[0098] The effectiveness of the method of this embodiment is further illustrated by a verification example below.

[0099] This verification case set up an experimental group and a control group.

[0100] The experimental group used Simulink to build a simulation system for RGV dual motor speed synchronization deviation coupling control based on sliding mode speed compensator. According to the actual situation, an S-shaped speed curve with an expected displacement of 18, an initial speed of 0, a final speed of 0, a maximum speed of 1.5, a maximum acceleration of 0.8, and a maximum jerk of 1.6 was set as the simulation given speed. The outer loop PID parameters P, I, and D were set to 22, 35, and 15, respectively. The parameters β, q, p, ε, τ, and Δ in the sliding mode controller were designed to be 0.5, 7, 9, 35, 50, and 0.002, respectively.

[0101] The control group used Simulink to build the RGV dual-motor speed synchronization deviation coupling control system based on the traditional PID speed compensator. The P, I, and D parameters of the traditional PID speed compensator were set to 5.5, 1.2, and 1.

[0102] During the simulation, the driving wheel motor is given an initial state of x1=0.05, x2=-0.1 at time zero. The driving wheel motor is given a random disturbance with a variance of 0.008 and a sampling time of 0.055. The driving wheel motor is given a random disturbance with a variance of 0.01 and a sampling time of 0.036.

[0103] The simulation results of the control group and the experimental group are as follows: Figure 4 , Figure 5 As shown in the figure. The black dotted line is the given speed of the system, the orange line represents the speed of the driving wheel motor 1, the green line represents the speed of the driving wheel motor 2, and the blue line represents the speed difference between the two driving wheel motors. The results show that the maximum value of the speed difference between the two driving wheel motors in the system using the traditional PID speed compensator is 1.013×10 -2 , the median is -2.658×10 -4 The maximum value of the speed difference between the two driving wheel motors in the system using the sliding mode speed compensator is 1.705×10 -3 , the median is 9.9×10 -6 . It can be seen that compared with the traditional PID speed compensator, the simulation results using the sliding mode speed compensator have exponential improvements in both the maximum value and the median. And from the blue line in the image, it can be seen that the sliding mode speed compensator makes the speed difference more stable and smoother to control it near 0, which significantly improves the stability of the dual-motor synchronization. It shows that the RGV dual-motor speed synchronization deviation coupling control system based on the sliding mode speed compensator of this embodiment enables the dual-motor driven RGV to have higher dual-motor synchronization, improves the stability and smoothness of its closed-loop control, and can ultimately affect the accuracy of RGV operation and its service life.

[0104] Example 2

[0105] See also Figure 3 This embodiment provides a RGV dual-motor speed synchronization deviation coupling control system, including:

[0106] The S-shaped speed curve generating module calculates the intermediate parameters of the S-shaped speed curve according to the expected operating parameters of the RGV, and generates the S-shaped speed curve for providing a reference speed value; the S-shaped speed curve uses the reference time as the horizontal coordinate and the speed value as the vertical coordinate.

[0107] Among them, a subroutine preset in the PLC controller of RGV is used to generate an S-shaped speed curve. During the generation of the S-shaped speed curve, the internal reference time of the subroutine is calculated by counting the constant interrupt time. The corresponding instantaneous speed value is calculated in the subroutine by the reference time value, and the voltage signal is output to inverter one and inverter two through the analog output port after linear transformation.

[0108] The expected operating parameters include the expected displacement, initial and final speeds, maximum speed, maximum acceleration, and maximum jerk of the RGV.

[0109] The PID controller output value calculation module calculates the instantaneous speed value on the S-shaped speed curve. Figure 3 The given speed shown in is subtracted from the collected RGV overall speed value to obtain the error value; the error value is input into the PID controller function module according to the set time period, and the output value of the PID controller is obtained as follows:

[0110] Δu x =K p *(e x -e x-1 )+K i *e x +K d *(e x -2*e x-1 +e x-2 )

[0111] Among them, Δu x is the output value of the PID controller at time x, K p , K i , K d are the P, I, and D parameters of the PID controller respectively, e represents the input error value, the subscripts x, x-1, and x-2 represent the x moment, x-1 moment, and x-2 moment respectively, and the difference between adjacent moments is the set time period.

[0112] The acquisition of the overall speed value of the RGV includes: acquiring the overall movement distance of the RGV at a constant time difference through an overall speed encoder, and the PLC controller calculates the real-time overall speed based on the acquisition interruption time of the overall speed encoder.

[0113] Among them, the task of the PID controller output value calculation module can be specifically executed by the PLC controller.

[0114] The sliding mode speed compensator output value calculation module subtracts the collected motor system 1 speed value and the motor system 2 speed value to obtain a speed error value; subtracts the collected motor system 1 speed value change rate and the motor system 2 speed value change rate to obtain a speed change rate error value; the speed error value and the speed change rate error value are input into the sliding mode speed compensator function module to obtain the output value of the sliding mode speed compensator as follows:

[0115]

[0116] Among them, u c is the output value of the sliding mode speed compensator, x 1 is the speed error value, x 2 is the speed change rate error value, β, q, p, ε, τ are design parameters, where β, ε, τ>0, p and q are two positive odd numbers and satisfy The sliding surface s is designed as:

[0117]

[0118] Among them, sat(s) is the saturation function, which is defined as follows:

[0119]

[0120] Δ is a positive real number.

[0121] The state space equations of the motor system 1 and the motor system 2 are the same, and the sliding mode speed compensator function module is designed for the state space equations, which are:

[0122]

[0123] Among them, x 1 is the speed error value, x 2 is the speed change rate error value, For x 1 The rate of change, For x 2 The rate of change, u c is the output value of the sliding mode compensator;

[0124] Among them, the task of the sliding mode speed compensator output value calculation module can be executed by the PLC controller. Specifically, the driving wheel motor encoder 1 and the driving wheel motor encoder 2 respectively collect corresponding rotation scales at a constant time difference, and the PLC controller calculates the motor system 1 speed value and speed value change rate based on the collection interruption time of the driving wheel motor encoder 1, and calculates the motor system 2 speed value and speed value change rate based on the collection interruption time of the driving wheel motor encoder 2.

[0125] a final speed value calculation module, which adds the output value of the PID controller to the corresponding instantaneous speed value on the S-shaped speed curve, and then subtracts the output value of the sliding mode speed compensator to obtain the preliminary speed of the driving wheel one, and adds the preliminary speed of the driving wheel one to the first correction value to obtain the final speed of the driving wheel one; adds the output value of the PID controller to the corresponding instantaneous speed value on the S-shaped speed curve, and then adds the output value of the sliding mode speed compensator to obtain the preliminary speed of the driving wheel two, and adds the preliminary speed value of the driving wheel two to the second correction value to obtain the final speed of the driving wheel two;

[0126] The first correction value and the second correction value are respectively the speed change values ​​reflected by considering the influence of external random disturbance on RGV;

[0127] The output module transmits the final speed of the driving wheel 1 and the final speed of the driving wheel 2 to the motor inverters of the two driving wheels of the RGV respectively.

[0128] The external random disturbance influence on each driving wheel is the same or different, such as Figure 3 As shown in perturbation 1 and perturbation 2.

[0129] Among them, the tasks of the final speed value calculation module and the output module can be executed by the PLC controller.

[0130] Those skilled in the art can understand that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention is described in detail with reference to the aforementioned embodiments, those skilled in the art can still modify the technical solutions recorded in the aforementioned embodiments or replace some of the technical features therein by equivalents. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

Claims

1. A RGV dual motor speed synchronization deviation coupling control method, characterized in that: include: S1. Calculating intermediate parameters of the S-shaped speed curve according to expected operating parameters of the RGV, and generating an S-shaped speed curve for providing a reference speed value; The S-shaped speed curve has the reference time as the horizontal coordinate and the speed value as the vertical coordinate; S2, subtract the instantaneous speed value on the S-shaped speed curve from the collected RGV overall speed value to obtain an error value; input the error value into the PID controller function module according to the set time period, and obtain the output value of the PID controller as follows: Δu x =K p *(and x -and x-1 )+K i *and x +K d *(and x -2*e x-1 +and x-2 ); Among them, Δu x is the output value of the PID controller at time x, K p , K i , K d are the P, I, and D parameters of the PID controller, respectively; e represents the input error value; the subscripts x, x-1, and x-2 represent the x moment, x-1 moment, and x-2 moment, respectively; and the difference between adjacent moments is the set time period; S3, subtracting the collected speed value of the motor system 1 from the speed value of the motor system 2 to obtain a speed error value; subtracting the collected change rate of the speed value of the motor system 1 from the change rate of the speed value of the motor system 2 to obtain a speed change rate error value; The speed error value and the speed change rate error value are input into the sliding mode speed compensator function module to obtain the output value of the sliding mode speed compensator as follows: Among them, u c is the output value of the sliding mode speed compensator, x1 is the speed error value, x2 is the speed change rate error value, β, q, p, ε, τ are design parameters, where β, ε, τ>0, p and q are two positive odd numbers and satisfy The sliding surface s is designed as: Among them, sat(s) is the saturation function, which is defined as follows: Δ is a positive real number; The motor system 1 includes a driving wheel 1, a driving wheel motor 1 and a frequency converter 1; The second motor system comprises a second driving wheel, a second driving wheel motor and a second frequency converter; The state space equations of the motor system 1 and the motor system 2 are the same, and the sliding mode speed compensator function module is designed for the state space equations, which are: Among them, x1 is the speed error value, x2 is the speed change rate error value, is the rate of change of x1, is the rate of change of x2, u c is the output value of the sliding mode compensator; S4, adding the output value of the PID controller to the corresponding instantaneous speed value on the S-shaped speed curve, and then subtracting the output value of the sliding mode speed compensator to obtain the preliminary speed of the driving wheel 1, and adding the preliminary speed of the driving wheel 1 to the first correction value to obtain the final speed of the driving wheel 1; The output value of the PID controller is added to the corresponding instantaneous speed value on the S-shaped speed curve, and then the output value of the sliding mode speed compensator is added to obtain the preliminary speed of the second driving wheel, and the preliminary speed value of the second driving wheel is added to the second correction value to obtain the final speed of the second driving wheel; The first correction value and the second correction value are respectively the speed change values ​​reflected by considering the influence of external random disturbance on RGV; S5. Transmit the final speed of the driving wheel 1 to the frequency converter 1, and transmit the final speed of the driving wheel 2 to the frequency converter 2.

2. The control method according to claim 1, characterized in that: In step S1, a subroutine preset in the PLC controller of the RGV is used to generate an S-shaped speed curve. During the generation of the S-shaped speed curve, the internal reference time of the subroutine is calculated by counting the constant interrupt time. The corresponding instantaneous speed value is calculated in the subroutine by the reference time value, and the voltage signal is output to the inverter 1 and the inverter 2 through the analog output port after linear transformation.

3. The control method according to claim 2, characterized in that: In step S2, the collection of the RGV overall speed value includes: collecting the overall movement distance of the RGV movement at a constant time difference through the overall speed encoder, and the PLC controller calculates the real-time overall speed based on the collection interruption time of the overall speed encoder.

4. The control method according to claim 2, characterized in that: In step S3, the encoder of the driving wheel motor 1 and the encoder of the driving wheel motor 2 respectively collect corresponding rotation scales at a constant time difference, and the PLC controller calculates the speed value and the speed value change rate of the motor system 1 based on the collection interruption time of the encoder of the driving wheel motor 1, and calculates the speed value and the speed value change rate of the motor system 2 based on the collection interruption time of the encoder of the driving wheel motor 2.

5. The control method according to claim 1, characterized in that: The expected operating parameters include the expected displacement, initial and final speeds, maximum speed, maximum acceleration, and maximum jerk of the RGV.

6. An RGV dual motor speed synchronization deviation coupling control system, characterized in that: include: An S-shaped speed curve generating module, which calculates intermediate parameters of the S-shaped speed curve according to expected operating parameters of the RGV, and generates an S-shaped speed curve for providing a reference speed value; the S-shaped speed curve has a reference time as a horizontal coordinate and a speed value as a vertical coordinate; The PID controller output value calculation module subtracts the instantaneous speed value on the S-shaped speed curve from the collected RGV overall speed value to obtain an error value; the error value is input into the PID controller function module according to the set time period, and the output value of the PID controller is obtained as follows: Δu x =K p *(and x -and x-1 )+K i *and x +K d *(and x -2*e x-1 +and x-2 ) Among them, Δu x is the output value of the PID controller at time x, K p , K i , K d are the P, I, and D parameters of the PID controller, respectively; e represents the input error value; the subscripts x, x-1, and x-2 represent the x moment, x-1 moment, and x-2 moment, respectively; and the difference between adjacent moments is the set time period; The sliding mode speed compensator output value calculation module subtracts the collected motor system 1 speed value and the motor system 2 speed value to obtain a speed error value; subtracts the collected motor system 1 speed value change rate and the motor system 2 speed value change rate to obtain a speed change rate error value; the speed error value and the speed change rate error value are input into the sliding mode speed compensator function module to obtain the output value of the sliding mode speed compensator as follows: Among them, u c is the output value of the sliding mode speed compensator, x1 is the speed error value, x2 is the speed change rate error value, β, q, p, ε, τ are design parameters, where β, ε, τ>0, p and q are two positive odd numbers and satisfy The sliding surface s is designed as: Among them, sat(s) is the saturation function, which is defined as follows: Δ is a positive real number; The motor system 1 includes a driving wheel 1, a driving wheel motor 1 and a frequency converter 1; The second motor system comprises a second driving wheel, a second driving wheel motor and a second frequency converter; The state space equations of the motor system 1 and the motor system 2 are the same, and the sliding mode speed compensator function module is designed for the state space equations, which are: Among them, x1 is the speed error value, x2 is the speed change rate error value, is the rate of change of x1, is the rate of change of x2, u c is the output value of the sliding mode compensator; a final speed value calculation module, which adds the output value of the PID controller to the corresponding instantaneous speed value on the S-shaped speed curve, and then subtracts the output value of the sliding mode speed compensator to obtain the preliminary speed of the driving wheel one, and adds the preliminary speed of the driving wheel one to the first correction value to obtain the final speed of the driving wheel one; adds the output value of the PID controller to the corresponding instantaneous speed value on the S-shaped speed curve, and then adds the output value of the sliding mode speed compensator to obtain the preliminary speed of the driving wheel two, and adds the preliminary speed value of the driving wheel two to the second correction value to obtain the final speed of the driving wheel two; The first correction value and the second correction value are respectively the speed change values ​​reflected by considering the influence of external random disturbance on RGV; An output module transmits the final speed of the driving wheel 1 to the frequency converter 1, and transmits the final speed of the driving wheel 2 to the frequency converter 2.

7. The control system according to claim 6, characterized in that: The S-shaped speed curve generation module uses a subroutine preset in the PLC controller of the RGV to generate an S-shaped speed curve. During the S-shaped speed curve generation process, the internal reference time of the subroutine is calculated by counting the constant interrupt time, and the corresponding instantaneous speed value is calculated in the subroutine by the reference time value, and the voltage signal is output to the inverter 1 and the inverter 2 through the analog output port after linear transformation.

8. The control system according to claim 7, characterized in that: The acquisition of the RGV overall speed value includes: acquiring the overall movement distance of the RGV movement at a constant time difference through an overall speed encoder, and the PLC controller calculates the real-time overall speed based on the acquisition interruption time of the overall speed encoder.

9. The control system according to claim 7, characterized in that: The encoder of the driving wheel motor 1 and the encoder of the driving wheel motor 2 respectively collect corresponding rotation scales at a constant time difference. The PLC controller calculates the speed value and the speed value change rate of the motor system 1 based on the collection interruption time of the encoder of the driving wheel motor 1, and calculates the speed value and the speed value change rate of the motor system 2 based on the collection interruption time of the encoder of the driving wheel motor 2.

10. The control system according to claim 6, characterized in that: The expected operating parameters include the expected displacement, initial and final speeds, maximum speed, maximum acceleration, and maximum jerk of the RGV.

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