Speed control brake bench and electric inertia simulation method based on torque feedforward and multi-speed loop parameters

Abstract

The application discloses a speed control brake bench and an electric inertia simulation method based on torque feedforward and multi-speed loop parameters, which comprises a controller, a torque sensor, an encoder, a driver and a motor; the encoder reads the current speed of a main shaft; the torque sensor obtains torque data of a brake disc; the controller processes the torque data to obtain a braking torque; according to the braking torque, a rotational inertia to be simulated and a total mechanical inertia currently mounted, a theoretical torque feedforward is obtained; the speed required in the next period is calculated, and the output torque is obtained in combination with the current feedback speed of the main shaft; and the driver is further used for driving the motor to drive the main shaft and the brake disc to rotate according to the output torque output by the controller. The application is based on the speed control with feedforward, and the program is simple to realize, and the inherent resistance measurement of the equipment is not necessary; the given torque is controlled in real time through the speed loop pid, and the speed error accumulated in the internal resistance compensation process is not introduced.

Description

Technical Field

[0001] This invention belongs to the field of electric inertia simulation of braking test benches, and particularly relates to a speed control braking test bench and electric inertia simulation method based on torque feedforward and multi-velocity loop parameters. Background Technology

[0002] With the rapid development of the automotive industry, the braking performance and NVH (Noise, Vibration, and Harshness) parameters of brakes are receiving increasing attention from OEMs. Brake inertia test benches are mainly used to test the braking performance and NVH performance of braking systems. Currently, brake inertia test benches primarily achieve electrical inertia simulation in two ways. One method is based on the controller or PLC calculating the required speed, and then sending the speed to the motor driver via analog signals or fieldbus. The driver's own speed loop controls the motor to run at the required speed to achieve electrical inertia simulation. The other method is based on the controller or PLC calculating the required torque, and then sending the torque to the motor driver via analog signals or fieldbus. The driver operates in torque mode or current mode to compensate for the torque required to simulate electrical inertia.

[0003] Both methods have their advantages and disadvantages. Method one, based on the speed loop of the actuator, has a simple and easy-to-implement overall control program. However, the speed loop parameters of the actuator cannot be uniformly adapted to different analog and mechanical inertia, and the speed response relies entirely on the output of the PID controller in the speed loop of the actuator, resulting in certain deficiencies in control accuracy and response speed. Method two can use well-developed theoretical formulas to calculate the torque required to compensate for inertia differences when different combinations of analog and mechanical inertia are used. However, it requires precise measurement of the inherent internal resistance of the equipment, such as the wind resistance of the inertia disk rotation and the rolling resistance of the bearings. Even if the wind resistance and bearing roller resistance are measured relatively accurately at each speed range, the speed error may still accumulate to a relatively large value over the entire braking speed range. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a speed control method based on torque feedforward and multiple speed loop parameters to simulate electric inertia. The method allows the motor driver to operate in torque or current mode, and speed loop control is implemented on the controller or PLC. By calculating the feedforward torque and the torque output by the speed loop PID controller, the sum of these two parameters is sent to the motor driver to simulate electric inertia. This method solves the slow response and poor accuracy problems of the first method by allowing the setting of multiple sets of PID parameters and theoretical feedforward torque. Furthermore, the PID parameters of the speed loop can automatically compensate for the wind resistance of the rotating inertia disk and the rolling resistance of the bearings, eliminating the need for precise measurement of these factors. It also avoids introducing error accumulation within the braking speed range.

[0005] To achieve the above objectives, the present invention provides the following technical solution:

[0006] A speed control braking test bench based on torque feedforward and multi-speed loop parameters includes a controller, a torque sensor, an encoder, a driver, and a motor;

[0007] The motor is connected to a brake disc via a main shaft;

[0008] The driver is used to drive the motor to rotate the main shaft and brake disc;

[0009] The encoder is used to read the current speed of the spindle;

[0010] The torque sensor is used to obtain the torque data of the brake disc;

[0011] The controller is used to process the torque data to obtain the braking torque; and to obtain the theoretical torque feedforward based on the braking torque, the moment of inertia to be simulated, and the total mechanical inertia of the current load; and to calculate the speed required for the next cycle and, in combination with the current feedback speed of the spindle, to obtain the output torque.

[0012] The driver is also used to drive the motor according to the output torque output by the controller.

[0013] Preferably, the controller includes: a low-pass filter unit, a deceleration calculation unit, a torque feedforward calculation unit, a control cycle speed calculation unit, a PID optimization unit, and a control torque calculation unit;

[0014] The low-pass filter unit is used to filter the torque data T. sensor The braking torque T is obtained by performing a first-order low-pass filter. b ;

[0015] The deceleration calculation unit is used to calculate the braking torque T. b and the moment of inertia I that needs to be simulated Sim The theoretical angular deceleration α is calculated.

[0016] The torque feedforward calculation unit is used to simulate the moment of inertia I as needed. Sim Theoretical angular deceleration α and total mechanical inertia I of the current load mech The theoretical torque feedforward F is calculated. Forward ;

[0017] The control cycle speed calculation unit is used to calculate the current set speed V of the spindle. Set i Based on the speed difference ΔV, the required speed V for the next control cycle is calculated. Set i+1 ;

[0018] The PID optimization unit is used to determine the required speed V for the next control cycle. Seti+1 And based on the total mechanical inertia of the current load, the PID parameters are optimized, and then combined with V Seti+1 The optimized control output F is obtained. PID ;

[0019] The control torque calculation unit is used to feed forward the theoretical torque F according to the control torque calculation unit. Forward and optimized control output F PID The output torque F is calculated.

[0020] Preferably, in the deceleration calculation unit, the theoretical angular deceleration α = T b / I Sim .

[0021] Preferably, in the torque feedforward calculation unit, the theoretical torque feedforward F Forward =(I Sim -I mech )·α.

[0022] Preferably, in the control cycle speed calculation unit, the speed difference ΔV = T·α·9.5493;

[0023] The speed V required for the next control cycle Set i+1 =V Set i -ΔV.

[0024] Preferably, if the current feedback speed V feedbacki <= preset brake release speed V Release If the output torque of the controller is 0, then the output torque F of the controller is 0.

[0025] This application also provides a method for simulating the electric inertia of a speed control braking test bench based on torque feedforward and multi-velocity loop parameters, comprising the following steps:

[0026] S0. Increase the speed of the brake disc to the braking start speed V. Brake Braking begins at time T0;

[0027] S1. Read the current feedback speed V of the spindle via the encoder. feedback， As the current set speed V Set0 ;

[0028] S2. Read the current feedback speed V of the spindle via the encoder. feedback i ;

[0029] S3. The controller reads the torque data T from the torque sensor. sensor The braking torque T is obtained after processing by a first-order low-pass filter.b ;

[0030] S4. Calculate the theoretical angular deceleration α = T b / I Sim , among which, I Sim This represents the moment of inertia that needs to be simulated.

[0031] S5. Calculate the theoretical torque feedforward F Forward =(I Sim -I mech )·α, where I mech This represents the total mechanical inertia currently mounted.

[0032] S6. Calculate the speed difference ΔV = T·α·9.5493, where T is the controller's calculation cycle;

[0033] S7. Calculate the speed V required for the next control cycle. Set i+1 =V Set i -ΔV;

[0034] S8. V Set i+1 Input to the PID controller; pre-set PID parameters for different mechanical inertia, and select the proportional K and integral parameters T of the PID controller according to the currently loaded mechanical inertia. I PID parameter optimization is performed.

[0035] S9. Based on the encoder's current feedback V feedback i and the optimized V Set i+1 Calculate the controller output F PID ;

[0036] S10. Calculate the controller output torque F = F Forward +F PID ;

[0037] S11. Determine the current feedback speed V feedback i Is it less than the preset brake release speed V? Release If V feedback i <=V Release If the controller outputs torque F = 0, proceed to S14; otherwise, proceed to S12.

[0038] S12. The controller output torque is sent to the driver via the bus;

[0039] S13. Repeat S2-S12;

[0040] S14. Exit the electric inertia simulation.

[0041] The beneficial effects of this invention are as follows:

[0042] The present invention relates to a speed control braking test bench and an electric inertia simulation method based on torque feedforward and multi-speed loop parameters. Based on speed control with feedforward, the program implementation is simple and does not require measurement of the inherent internal resistance of the equipment. The given torque is controlled in real time through the speed loop PID, which does not introduce the speed error accumulated during the internal resistance compensation process. Since the feedforward torque and PID parameters can be adjusted in real time on the controller according to the actual size of the inertia disk, fast response and control accuracy can be achieved. Attached Figure Description

[0043] To more clearly illustrate the technical solution of the present invention, the drawings used in the embodiments are briefly described below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0044] Figure 1 This is a schematic diagram of a complete set of equipment according to an embodiment of the present invention;

[0045] Figure 2 This is a simplified electrical structure diagram of an embodiment of the present invention;

[0046] Figure 3 This is a schematic diagram comparing braking process data from 80-30km / h (572rpm-285rpm) under different control methods according to an embodiment of the present invention. Detailed Implementation

[0047] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0048] Example 1

[0049] like Figure 1 The diagram shown is a schematic of a complete set of equipment according to an embodiment of the present invention. In the diagram, the encoder is used to read the feedback speed, the motor is used to drive the main shaft and brake disc to rotate, the mechanical inertia disk is used to express the total mechanical inertia of the load, the torque sensor (or force sensor) is used to sense the torque (or force) on the brake disc, and the test brake connecting flange is used to connect the test brake disc. On the other side of the stand, a brake caliper is mounted on the fixed tailstock, and the brake caliper applies a braking effect to the brake disc. A simplified electrical structure diagram is shown below. Figure 2As shown.

[0050] Specifically, in this embodiment, the speed control braking test bench based on torque feedforward and multi-speed loop parameters mainly includes a controller, a torque sensor, an encoder, a driver, and a motor. The motor is connected to a brake disc via a main shaft.

[0051] The system comprises a driver that drives the motor to rotate the spindle and brake disc. An encoder reads the current speed of the spindle. A torque sensor obtains the torque data of the brake disc. The controller processes the torque data to obtain the braking torque. It also calculates the theoretical torque feedforward based on the braking torque, the moment of inertia to be simulated, and the total mechanical inertia of the current load. Furthermore, it calculates the speed required for the next cycle and, combined with the current feedback speed of the spindle, obtains the output torque. The driver also drives the motor based on the output torque output by the controller.

[0052] In this embodiment, the controller specifically consists of a low-pass filter unit, a deceleration calculation unit, a torque feedforward calculation unit, a control cycle speed calculation unit, and a control torque calculation unit.

[0053] The low-pass filter unit is used to process the torque data T. sensor A first-order low-pass filter is performed to obtain the braking torque T. b .

[0054] The deceleration calculation unit is used to calculate the braking torque T. b and the moment of inertia I that needs to be simulated Sim The theoretical angular deceleration α is calculated, α = T b / I Sim That is, angular deceleration = torque / moment of inertia.

[0055] The torque feedforward calculation unit is used to simulate the moment of inertia I as needed. Sim Theoretical angular deceleration α and total mechanical inertia I of the current load mech The theoretical torque feedforward F was calculated. Forward F Forward =(I Sim -I mech )·α.

[0056] The control cycle speed calculation unit is used to calculate the current set speed V of the spindle. Seti Based on the speed difference ΔV, the required speed V for the next control cycle is calculated. Set i+1 Where ΔV = T·α·9.5493, and T is the controller's calculation cycle. Set i+1 =V Set i -ΔV.

[0057] The control torque calculation unit is used to calculate the current feedback speed V of the spindle. feedback i and the speed V required for the next control cycle Set i+1 The control output F is obtained. PID Then, feedforward with the theoretical torque F Forward Add them together and calculate the output torque F, F = F Forward +F PID .

[0058] In addition, a PID unit is added to this embodiment to adjust the speed V required for the next control cycle. Set i+1 PID error optimization is performed based on the total mechanical inertia of the current mounting.

[0059] Finally, determine the current feedback speed V. feedbacki Is it less than the preset brake release speed V? Release If V feedback i <=V Release If the output torque of the controller is F = 0, then the output torque of the controller is 0.

[0060] The method for simulating the electric inertia of the aforementioned braking test bench mainly includes the following steps:

[0061] S0. Increase the speed of the brake disc to the braking start speed V. Brake Braking begins at time T0.

[0062] S1. Read the current feedback speed V of the spindle via the encoder. feedback， As the current set speed V Set0 The unit is rpm.

[0063] S2. Read the current feedback speed V of the spindle via the encoder. feedback i .

[0064] S3. The controller reads the torque data T from the torque sensor. sensor The braking torque T is obtained after processing by a first-order low-pass filter. b .

[0065] S4. Calculate the theoretical angular deceleration α = T b / I Sim That is, angular deceleration = torque / moment of inertia, where I Sim This represents the moment of inertia that needs to be simulated.

[0066] S5. Calculate the theoretical torque feedforward F Forward =(I Sim -I mech)·α, where I mech This represents the total mechanical inertia currently mounted.

[0067] S6. Calculate the speed difference ΔV = T·α·9.5493, in rpm, where T is the controller's calculation cycle and 9.5493 ​​is the conversion ratio between radians and angular velocity.

[0068] S7. Calculate the speed V required for the next control cycle. Set i+1 =V Set i -ΔV.

[0069] S8. To further optimize and reduce the error, V Set i+1 Input is passed to the PID controller.

[0070] Pre-set PID parameters for different mechanical inertia values, and select the proportional K and integral parameters T of the PID controller based on the currently mounted mechanical inertia. I In this embodiment, the scaling factor of one inertia disk is 40 and the integration time is 1000ms; the scaling factor of two inertia disks is 60 and the integration time is 800ms; and the scaling factor of three inertia disks is 80 and the integration time is 800ms.

[0071] S9. Based on the encoder's current feedback V feedback i and the speed V required for the next control cycle Set i+1 Calculate the controller output F PID .

[0072] S10. Calculate the controller output torque F = F Forward +F PID .

[0073] S11. Determine the current feedback speed V feedback i Is it less than the preset brake release speed V? Release If V feedback i <=V Release If the controller outputs torque F = 0, proceed to S13. Otherwise, proceed to S12.

[0074] S12. The controller output torque is sent to the driver via the bus.

[0075] S13. Repeat S2-S11.

[0076] S14. Exit the electric inertia simulation.

[0077] This control method can be used not only for simulating electric inertia but also for general speed control by adjusting the feedforward torque and speed setpoint. At the start of braking, the torque value from the torque sensor (or torque sensor) is read. The current deceleration is calculated using the corrected and filtered sensor data and the inertia to be simulated. Based on the calculated deceleration and the controller's control cycle, the required speed for the next cycle is calculated. Simultaneously, the motor torque feedforward is calculated based on the difference between the mechanical inertia and the inertia to be simulated, along with the calculated deceleration. The calculated speed for the next cycle is then used as the speed loop setpoint. The speed loop's PID controller approximates the setpoint, and the PID output automatically compensates for the system's inherent internal resistance, eliminating the need for highly precise internal resistance measurements.

[0078] Figure 3 The diagram illustrates braking process data from 80-30 km / h (572 rpm-285 rpm) using different control methods. bbk represents the data from this invention. Comparison 1 uses the speed loop of the driver to control speed, with the controller sending speed data to the driver. Comparison 2 uses theoretical torque to compensate for inertia, without speed control. It can be seen that Comparison 1 exhibits a significant slow response at the start of deceleration. In Comparison 2, during the latter half of braking, the error between the compensated theoretical torque and the actual torque under operating conditions accumulates, causing the speed to deviate further and further from the set speed.

[0079] The embodiments described above are merely preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Various modifications and improvements made to the technical solutions of the present invention by those skilled in the art without departing from the spirit of the present invention should fall within the protection scope defined by the claims of the present invention.

Claims

1. A speed control brake bench based on torque feedforward and multi-speed loop parameters, characterized in that, a controller, a torque sensor, an encoder, a driver and a motor are included; the motor is connected with a brake disc through a main shaft; the driver is used to drive the motor to rotate the main shaft and the brake disc; the encoder is used to read the current speed of the main shaft; The torque sensor is used to obtain torque data T of the brake disc sensor ; The controller is configured to process the torque data to obtain a braking torque T b ; and , according to the braking torque T b , the moment of inertia I Sim to be simulated, and the total mechanical moment of inertia I mech currently mounted, the theoretical torque feedforward F Forward is obtained; and the speed V Set i+1 required in the next control cycle is calculated, and combined with the current feedback speed V feedback i of the main shaft, the output torque F is obtained; the driver is also used to drive the motor according to the output torque F output by the controller; the controller includes a low-pass filter unit, a deceleration calculation unit, a torque feedforward calculation unit, a control cycle speed calculation unit, a PID optimization unit and a control torque calculation unit; The low-pass filter unit is configured to perform a first-order low-pass filtering on the torque data T sensor to obtain the braking torque T b ; The deceleration calculation unit is configured to calculate a theoretical angular deceleration a based on the braking torque T b and a moment of inertia I Sim that needs to be simulated, where the theoretical angular deceleration a = T b / I Sim ; The torque feedforward calculation unit is used to calculate the theoretical torque feedforward F Sim , theoretical angular deceleration a and the total mechanical inertia I mech currently mounted according to the required simulated rotational inertia I Forward , the theoretical torque feedforward F Forward = (I Sim -I mech ) · a; The control cycle speed calculating unit is configured to calculate a speed V Set i needed in a next control cycle according to a current set speed V Set i+1 of the spindle and a speed difference AV, wherein the speed difference AV = T · a · 9.5493, T is a calculation cycle of the controller; the speed V Set i+1 needed in the next control cycle is V Set i - AV; The PID optimization unit is used to optimize PID parameters according to the required speed V Set i+1 of the next control period, in combination with the total mechanical inertia currently mounted Set i+1 , to obtain the optimized control output F PID ; The control torque calculation unit is configured to feed forward the theoretical torque F Forward and the optimized control output F PID , and calculate the output torque F, F=F Forward +F PID ; if the current feedback speed V feedbacki <= the preset brake release speed V Release , the output torque F of the controller is 0.

2. An electric inertia simulation method for a speed control brake rig based on torque feedforward and multi-speed loop parameters, using the brake rig of claim 1, characterized in that, the following steps are included: S0. The brake disc is accelerated to the brake start speed V Brake , the braking T0 moment starts; S1. Read spindle current feedback speed V by encoder feedback， as current set speed V Set0 ; S2. Read spindle current feedback speed V by encoder feedback i ; S3. The controller reads the torque data T of the torque sensor sensor and is processed by a first order low pass filter to obtain the braking torque T b ; S4. Calculate the theoretical angular deceleration a = T b / I Sim where I Sim denotes the moment of inertia to be simulated; S5. Compute theoretical torque feedforward F Forward = (I Sim - I mech ) · a, where I mech denotes the total mechanical inertia currently mounted. S6.Calculate the speed difference ΔV = T·α·9.5493, wherein T is the calculation period of the controller; S7. Calculate the speed V needed for the next control period Set i+1 = V Set i - ΔV; S8. V Set i+1 Incoming PID controller input; pre-set PID parameters for different mechanical inertia, select PID controller proportion K and integral parameter T according to the current mounted mechanical inertia I PID parameter optimization, S9. According to the encoder current feedback speed V feedback i and optimized V Set i+1 Calculate the controller output F PID ; S10. The controller outputs a torque F = F Forward F PID ; S11. Determine whether the current feedback speed V feedback i is less than a preset brake release speed V Release , if V feedback i <= V Release , the controller outputs a torque F = 0, and the process goes to S14, otherwise, the process goes to S12; S12.Send the controller output torque to the driver through the bus; S13.Repeat S2-S12; S14.Exit the electric inertia simulation.

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