A Braking Mode Switching Consistency Control System and its Control Method

Abstract

This invention discloses a braking mode switching consistency control system and its control method, comprising: a target braking force acquisition device, a hydraulic braking force detection device, a hydraulic braking force storage device, a braking consistency control device, a hydraulic braking force control device, and an electric motor power control device. This invention avoids braking force shock during braking mode switching by compensating for hydraulic braking force with electric motor power. It utilizes pressure build-up datasets and pressure release datasets to train a neural network to obtain dynamic response curves of hydraulic braking force during the pressure build-up or pressure release processes corresponding to different current and target hydraulic braking forces. The electric motor power response curve is then calculated from the hydraulic braking force dynamic response curve, improving compensation accuracy and avoiding braking force shock during braking mode switching caused by motor response lag, thus preventing a poor driving experience.

Description

Technical Field

[0001] This invention belongs to the field of automotive braking control technology, specifically relating to a braking mode switching consistency control system and its control method. Background Technology

[0002] With the advancement of energy conservation in automobiles, electric vehicles have experienced rapid development. Electric vehicles boast high energy efficiency, maximizing both economic and social benefits. Compared to traditional vehicles, electric vehicles have a significant advantage: they can recover a portion of braking energy. Regenerative braking, or brake energy recovery, refers to the process where, during braking, the vehicle's motor generates electricity. The mechanical energy generated during this process is transmitted to the motor via the vehicle's transmission system. Simultaneously, the motor produces braking torque. This regenerative braking torque, along with hydraulic braking torque, acts on the wheels to decelerate the vehicle. The combined action of hydraulic and regenerative braking torque produces three braking modes: pure regenerative braking, pure hydraulic braking, and a combination of regenerative and hydraulic braking. The braking mode switches according to changes in braking intensity. During mode switching, because the regenerative braking system responds faster than the hydraulic braking system, sudden changes in braking force can occur, causing significant impacts and affecting the smoothness of braking, resulting in a poor driving experience.

[0003] Chinese invention patent application number CN201811037301.6 discloses an impact control method based on motor compensation. This method proposes a motor compensation strategy to address the difference in response speed between the motor braking subsystem and the hydraulic braking subsystem in a vehicle's composite braking system. The motor braking force is used as the control coordination quantity, and the hydraulic braking force is used as the disturbance quantity to establish motor compensation control. However, this method does not take into account that the motor response will still have a certain delay and that the feedback signal will be subject to external interference during transmission, resulting in lag or fluctuation, which causes braking impact to still exist during the braking mode switching process. Summary of the Invention

[0004] To address the shortcomings of the existing technology, the present invention aims to provide a braking mode switching consistency control system and its control method, so as to solve the problem of sudden braking force changes caused by inconsistent response speed of the electro-hydraulic braking system during the braking mode switching process, and the problem of poor driving experience caused by braking force fluctuations during braking.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] The present invention provides a braking mode switching consistency control system, comprising: a target braking force acquisition device, a hydraulic braking force detection device, a hydraulic braking force storage device, a braking consistency control device, a hydraulic braking force control device, and an electric motor power control device;

[0007] A target braking force acquisition device is used to acquire the target hydraulic braking force and target electric motor power of the braking system;

[0008] A hydraulic braking force detection device is used to detect the real-time hydraulic braking force output by a hydraulic braking system.

[0009] A hydraulic braking force storage device for storing hydraulic braking force response curves;

[0010] The braking consistency control device is connected to the target braking force acquisition device, the hydraulic braking force detection device, the hydraulic braking force storage device, the hydraulic braking force control device, and the electric motor power control device. It is used to obtain the corresponding hydraulic braking force response curve from the hydraulic braking force storage device based on the target hydraulic braking force obtained by the target braking force acquisition device and the real-time hydraulic braking force obtained by the hydraulic braking force detection device. It calculates the electric motor power compensation value based on the obtained hydraulic braking force response curve and the target hydraulic braking force obtained by the target braking force acquisition device. It calculates the electric motor power response curve based on the electric motor power compensation value and the target electric motor power obtained by the target braking force acquisition device. It sends the hydraulic braking force response curve and the electric motor power response curve to the hydraulic braking force control device and the electric motor power control device, respectively. During the control process, it corrects the hydraulic braking force response curve based on the real-time hydraulic braking force obtained by the hydraulic braking system obtained by the hydraulic braking force detection device.

[0011] A hydraulic braking force control device is used to control the target braking force of the hydraulic braking system based on the hydraulic braking force response curve calculated by the braking consistency control device.

[0012] An electric motor power control device is used to control the target braking force of the motor braking system based on the electric motor power response curve calculated by the braking consistency control device.

[0013] Furthermore, the hydraulic braking force detection device is a hydraulic braking force sensor.

[0014] Furthermore, the hydraulic braking force response curves stored in the hydraulic braking force storage device include pressure build-up response curves and pressure relief response curves. These pressure build-up and pressure relief response curves are obtained using a neural network for curve fitting. The specific curve fitting process is as follows:

[0015] (1) By performing multiple pressure build-up and pressure release processes with different target hydraulic braking forces using a hydraulic braking system, pressure build-up dataset x1 and pressure release dataset x2 are obtained. Pressure build-up dataset x1 contains the real-time pressure build-up force F. 1n Real-time pressure build-up response time t 1n Initial braking force F 10n and the target braking force F 11n The pressure relief dataset x2 contains real-time pressure relief force F. 2n Real-time pressure relief response time t 2n Initial braking force F during depressurization 20n and depressurization target braking force F 21n ;

[0016] (2) Design a 3-layer neural network model, which includes 1 input layer, 1 hidden layer, and 1 output layer; the input layer has 3 inputs, the hidden layer has 5 nodes, and the output layer has 1 output;

[0017] (3) Set the activation function of the neural network model as follows: The loss function is In the formula, S(x) is the activation function value, e is the natural exponent, L is the loss function value, x is the input variable, N is the number of training data, and y pred For the predicted value, y pred The actual value;

[0018] (4) Perform curve fitting training for the pressure build-up process, randomize the neural network weights, and combine the real-time pressure build-up response time t1 and the initial braking force F in the pressure build-up dataset x1. 10 and the target braking force F 11 As input, the real-time pressure build-up force F1 is used as output to train the neural network. The weight parameters of the neural network are updated according to the loss function value after each training until the loss function value no longer changes, and the response curve y1 of the hydraulic braking force build-up process is obtained.

[0019] (5) Perform curve fitting training for the depressurization process, randomize the neural network weights, and combine the real-time depressurization response time t1 and the initial depressurization braking force F in the depressurization dataset x2. 20 and depressurization target braking force F 21 As input, the real-time pressure relief force F2 is used as output to train the neural network. The weight parameters of the neural network are updated according to the loss function value after each training until the loss function value no longer changes, thus obtaining the hydraulic braking force relief process response curve y2.

[0020] The present invention provides a control method for a braking mode switching consistency control system, based on the above system, comprising the following steps:

[0021] 1) Before the braking mode switching process, the braking consistency control device uses the target hydraulic braking force F obtained by the target braking force acquisition device. h The real-time hydraulic braking force F obtained by the hydraulic braking force detection device ht Obtain the hydraulic braking force response curve F corresponding to the target hydraulic braking force from the hydraulic braking force storage device. h (t);

[0022] 2) The braking consistency control device is based on the hydraulic braking force response curve F h (t) and target hydraulic braking force F h Calculate the motor power compensation value ΔF m ;

[0023] 3) The braking consistency control device is based on the motor power compensation value ΔF. m and target electric motor power F m Calculate the dynamic response curve F of the electric motor m (t);

[0024] 4) The braking consistency control device will apply the target hydraulic braking force F h and the dynamic response curve F of the electric motor m (t) are respectively transmitted to the hydraulic braking force control device and the electric motor power control device;

[0025] 5) During the braking mode switching process, the hydraulic braking force detection device will detect the hydraulic braking force F in real time. ht The data is transmitted to the braking consistency control device, which then determines the braking consistency control device based on the real-time hydraulic braking force F. ht And target hydraulic braking force F h The corresponding hydraulic braking force response curve F h (t) Calculate the error and determine whether the hydraulic braking force response curve F needs to be adjusted. h (t) is used for correction control.

[0026] Further, step 2) specifically includes:

[0027] The target hydraulic braking force is F h The dynamic response curve of the hydraulic braking force corresponding to the target hydraulic braking force is F. h (t), then the motor power compensation value is ΔF m =F h -F h (t).

[0028] Furthermore, step 3) specifically includes:

[0029] The electric motor power compensation value is ΔF m The target electric motor's power is F mThe dynamic response curve of the electric motor is F. m (t)=F m +ΔF m .

[0030] Furthermore, step 5) specifically includes:

[0031] 51) Based on the real-time hydraulic braking force F ht And target hydraulic braking force F h The corresponding hydraulic braking force response curve F h (t) Calculate the hydraulic braking force error Δ t Real-time hydraulic braking force F ht Corresponding dynamic response curve F of hydraulic braking force h The hydraulic braking force at the same moment (t) is F, and the error of the hydraulic braking force is calculated in real time. If the hydraulic braking force error is less than or equal to 2%, the requirement is met; otherwise, the requirement is not met.

[0032] 52) If all hydraulic braking force errors meet the requirements, the hydraulic braking force response curve corresponding to the target braking force remains unchanged; if there is a hydraulic braking force error Δ t If the requirements are not met, calculate the hydraulic braking force correction value. The hydraulic braking force correction value is substituted into the hydraulic braking force response curve for correction and optimization. The corresponding hydraulic braking force at the same moment becomes F', F'=F+ΔF.

[0033] The beneficial effects of this invention are:

[0034] This invention compensates for hydraulic braking force with electric motor power to avoid braking force shock during braking mode switching. It utilizes pressure build-up and pressure release datasets to train a neural network that generates dynamic response curves for the hydraulic braking force during the pressure build-up or pressure release processes, corresponding to different current and target hydraulic braking forces. The electric motor power response curve is then calculated from these dynamic response curves, improving compensation accuracy and preventing braking force shock during braking mode switching caused by motor response lag, thus avoiding a poor driving experience. Simultaneously, during the tracking process, the calculation error of the dynamic response curves for the real-time and target hydraulic braking forces is assessed to ensure they meet requirements, further improving compensation accuracy through real-time error judgment. Attached Figure Description

[0035] Figure 1 This is a schematic diagram of the system of the present invention.

[0036] Figure 2 This is a schematic diagram of the process for obtaining the hydraulic braking force response curve in this invention.

[0037] Figure 3This is a schematic diagram of the neural network used in this invention to train the hydraulic braking force response curve. Detailed Implementation

[0038] To facilitate understanding by those skilled in the art, the present invention will be further described below with reference to embodiments and accompanying drawings. The content mentioned in the embodiments is not intended to limit the present invention.

[0039] Reference Figure 1 As shown, a braking mode switching consistency control system of the present invention includes: a target braking force acquisition device 10, a hydraulic braking force detection device 11, a hydraulic braking force storage device 12, a braking consistency control device 13, a hydraulic braking force control device 14, and an electric motor power control device 15.

[0040] The target braking force acquisition device 10 is used to acquire the target hydraulic braking force and the target electric motor power of the braking system.

[0041] The hydraulic braking force detection device 11 is used to detect the real-time hydraulic braking force output by the hydraulic braking system; the hydraulic braking force detection device 11 is a hydraulic braking force sensor.

[0042] Hydraulic braking force storage device 12, used to store hydraulic braking force response curves;

[0043] The hydraulic braking force storage device 12 stores hydraulic braking force response curves including pressure build-up response curves and pressure release response curves. These curves are obtained using a neural network for curve fitting. Figure 2 As shown, the specific curve fitting process is as follows:

[0044] (1) By performing multiple pressure build-up and pressure release processes with different target hydraulic braking forces using a hydraulic braking system, pressure build-up dataset x1 and pressure release dataset x2 are obtained. Pressure build-up dataset x1 contains the real-time pressure build-up force F. 1n Real-time pressure build-up response time t 1n Initial braking force F 10n and the target braking force F 11n The pressure relief dataset x2 contains real-time pressure relief force F. 2n Real-time pressure relief response time t 2n Initial braking force F during depressurization 20n and depressurization target braking force F 21n ;

[0045] (2) Design a 3-layer neural network model, such as Figure 3 As shown, it contains one input layer, one hidden layer, and one output layer; the input layer has three inputs, the hidden layer has five nodes, and the output layer has one output.

[0046] (3) Set the activation function of the neural network model as follows: The loss function is In the formula, S(x) is the activation function value, e is the natural exponent, L is the loss function value, x is the input variable, N is the number of training data, and y pred For the predicted value, y pred The actual value;

[0047] (4) Perform curve fitting training for the pressure build-up process, randomize the neural network weights, and combine the real-time pressure build-up response time t1 and the initial braking force F in the pressure build-up dataset x1. 10 and the target braking force F 11 As input, the real-time pressure build-up force F1 is used as output to train the neural network. The weight parameters of the neural network are updated according to the loss function value after each training until the loss function value no longer changes, and the response curve y1 of the hydraulic braking force build-up process is obtained.

[0048] (5) Perform curve fitting training for the depressurization process, randomize the neural network weights, and combine the real-time depressurization response time t1 and the initial depressurization braking force F in the depressurization dataset x2. 20 and depressurization target braking force F 21 As input, the real-time pressure relief force F2 is used as output to train the neural network. The weight parameters of the neural network are updated according to the loss function value after each training until the loss function value no longer changes, thus obtaining the hydraulic braking force relief process response curve y2.

[0049] Braking consistency control device 13 is connected to target braking force acquisition device 10, hydraulic braking force detection device 11, hydraulic braking force storage device 12, hydraulic braking force control device 14, and electric motor power control device 15, respectively. It is used to obtain the corresponding hydraulic braking force response curve from hydraulic braking force storage device 12 based on the target hydraulic braking force obtained by target braking force acquisition device 10 and the real-time hydraulic braking force obtained by hydraulic braking force detection device 11, calculate the electric motor power compensation value based on the obtained hydraulic braking force response curve and the target hydraulic braking force obtained by target braking force acquisition device 10, calculate the electric motor power response curve based on the electric motor power compensation value and the target electric motor power obtained by target braking force acquisition device 10, and send the hydraulic braking force response curve and the electric motor power response curve to hydraulic braking force control device 14 and electric motor power control device 15, respectively. During the control process, it is corrected based on the hydraulic braking force response curve corresponding to the real-time hydraulic braking force obtained by the hydraulic braking system obtained by hydraulic braking force detection device 11.

[0050] The hydraulic braking force control device 14 is used to control the target braking force of the hydraulic braking system according to the hydraulic braking force response curve calculated by the braking consistency control device 13.

[0051] The electric motor power control device 15 is used to control the target braking force of the motor braking system based on the electric motor power response curve calculated by the braking consistency control device 13.

[0052] The present invention provides a control method for a braking mode switching consistency control system, based on the above system, comprising the following steps:

[0053] 1) Before the braking mode switching process, the braking consistency control device uses the target hydraulic braking force F obtained by the target braking force acquisition device. h The real-time hydraulic braking force F obtained by the hydraulic braking force detection device ht Obtain the hydraulic braking force response curve F corresponding to the target hydraulic braking force from the hydraulic braking force storage device. h (t);

[0054] 2) The braking consistency control device is based on the hydraulic braking force response curve F h (t) and target hydraulic braking force F h Calculate the motor power compensation value ΔF m ;

[0055] The target hydraulic braking force is F h The dynamic response curve of the hydraulic braking force corresponding to the target hydraulic braking force is F. h (t), then the motor power compensation value is ΔF m =F h -F h (t).

[0056] 3) The braking consistency control device is based on the motor power compensation value ΔF. m and target electric motor power F m Calculate the dynamic response curve F of the electric motor m (t);

[0057] The electric motor power compensation value is ΔF m The target electric motor's power is F m The dynamic response curve of the electric motor is F. m (t)=F m +ΔF m .

[0058] 4) The braking consistency control device will apply the target hydraulic braking force F h and the dynamic response curve F of the electric motor m (t) are respectively transmitted to the hydraulic braking force control device and the electric motor power control device;

[0059] 5) During the braking mode switching process, the hydraulic braking force detection device will detect the hydraulic braking force F in real time. ht The data is transmitted to the braking consistency control device, which then determines the braking consistency control device based on the real-time hydraulic braking force F. ht And target hydraulic braking force F h The corresponding hydraulic braking force response curve F h (t) Calculate the error and determine whether the hydraulic braking force response curve F needs to be adjusted. h (t) Perform corrective control; specifically including:

[0060] 51) Based on the real-time hydraulic braking force F ht And target hydraulic braking force F h The corresponding hydraulic braking force response curve F h (t) Calculate the hydraulic braking force error Δ t Real-time hydraulic braking force F ht Corresponding dynamic response curve F of hydraulic braking force h The hydraulic braking force at the same moment (t) is F, and the error of the hydraulic braking force is calculated in real time. If the hydraulic braking force error is less than or equal to 2%, the requirement is met; otherwise, the requirement is not met.

[0061] 52) If all hydraulic braking force errors meet the requirements, the hydraulic braking force response curve corresponding to the target braking force remains unchanged; if there is a hydraulic braking force error Δ t If the requirements are not met, calculate the hydraulic braking force correction value. The hydraulic braking force correction value is substituted into the hydraulic braking force response curve for correction and optimization. The corresponding hydraulic braking force at the same moment becomes F', F'=F+ΔF.

[0062] This invention has many specific applications. The above description is only a preferred embodiment of this invention. It should be noted that for those skilled in the art, several improvements can be made without departing from the principle of this invention, and these improvements should also be considered within the scope of protection of this invention.

Claims

1. A braking mode switching consistency control system, characterized in that, include: Target braking force acquisition device, hydraulic braking force detection device, hydraulic braking force storage device, braking consistency control device, hydraulic braking force control device, and electric motor power control device; A target braking force acquisition device is used to acquire the target hydraulic braking force and the target electric motor power of the braking system; A hydraulic braking force detection device is used to detect the real-time hydraulic braking force output by a hydraulic braking system. A hydraulic braking force storage device for storing hydraulic braking force response curves; The braking consistency control device is connected to the target braking force acquisition device, the hydraulic braking force detection device, the hydraulic braking force storage device, the hydraulic braking force control device, and the electric motor power control device. It is used to obtain the corresponding hydraulic braking force response curve from the hydraulic braking force storage device based on the target hydraulic braking force obtained by the target braking force acquisition device and the real-time hydraulic braking force obtained by the hydraulic braking force detection device. It calculates the electric motor power compensation value based on the obtained hydraulic braking force response curve and the target hydraulic braking force obtained by the target braking force acquisition device. It calculates the electric motor power response curve based on the electric motor power compensation value and the target electric motor power obtained by the target braking force acquisition device. It sends the hydraulic braking force response curve and the electric motor power response curve to the hydraulic braking force control device and the electric motor power control device, respectively. During the control process, it corrects the hydraulic braking force response curve based on the real-time hydraulic braking force obtained by the hydraulic braking system obtained by the hydraulic braking force detection device. A hydraulic braking force control device is used to control the target braking force of the hydraulic braking system based on the hydraulic braking force response curve calculated by the braking consistency control device. An electric motor power control device is used to control the target braking force of the motor braking system based on the electric motor power response curve calculated by the braking consistency control device. The hydraulic braking force storage device stores hydraulic braking force response curves including pressure build-up response curves and pressure release response curves. These curves are obtained by curve fitting using a neural network. The specific curve fitting process is as follows: (1) By performing multiple pressure build-up and pressure release processes with different target hydraulic braking forces using a hydraulic braking system, pressure build-up dataset x1 and pressure release dataset x2 are obtained. Pressure build-up dataset x1 contains the real-time pressure build-up force F. 1n Real-time pressure build-up response time t 1n Initial braking force F 10n and the target braking force F 11n The pressure relief dataset x2 contains real-time pressure relief force F. 2n Real-time pressure relief response time t 2n Initial braking force F during depressurization 20n and depressurization target braking force F 21n ; (2) Design a 3-layer neural network model, which includes 1 input layer, 1 hidden layer, and 1 output layer; the input layer has 3 inputs, the hidden layer has 5 nodes, and the output layer has 1 output; (3) Set the activation function of the neural network model as follows: The loss function is In the formula, S(x) is the activation function value, e is the natural exponent, L is the loss function value, x is the input variable, N is the number of training data, and y pred For the predicted value, y pred The actual value; (4) Perform curve fitting training for the pressure build-up process, randomize the neural network weights, and combine the real-time pressure build-up response time t1 and the initial braking force F in the pressure build-up dataset x1. 10 and the target braking force F 11 As input, the real-time pressure build-up force F1 is used as output to train the neural network. The weight parameters of the neural network are updated according to the loss function value after each training until the loss function value no longer changes, and the response curve y1 of the hydraulic braking force build-up process is obtained. (5) Perform curve fitting training for the depressurization process, randomize the neural network weights, and combine the real-time depressurization response time t1 and the initial depressurization braking force F in the depressurization dataset x2. 20 and depressurization target braking force F 21 As input, the real-time pressure relief force F2 is used as output to train the neural network. The weight parameters of the neural network are updated according to the loss function value after each training until the loss function value no longer changes, thus obtaining the hydraulic braking force relief process response curve y2.

2. The braking mode switching consistency control system according to claim 1, characterized in that, The hydraulic braking force detection device is a hydraulic braking force sensor.

3. A control method for a braking mode switching consistency control system, based on any one of claims 1-2, characterized in that, The steps are as follows: 1) Before the braking mode switching process, the braking consistency control device uses the target hydraulic braking force F obtained by the target braking force acquisition device. h The real-time hydraulic braking force F obtained by the hydraulic braking force detection device ht Obtain the hydraulic braking force response curve F corresponding to the target hydraulic braking force from the hydraulic braking force storage device. h (t); 2) The braking consistency control device is based on the hydraulic braking force response curve F h (t) and target hydraulic braking force F h Calculate the motor power compensation value ΔF m ; 3) The braking consistency control device is based on the motor power compensation value ΔF. m and target electric motor power F m Calculate the dynamic response curve F of the electric motor m (t); 4) The braking consistency control device will apply the target hydraulic braking force F h and the dynamic response curve F of the electric motor m (t) are respectively transmitted to the hydraulic braking force control device and the electric motor power control device; 5) During the braking mode switching process, the hydraulic braking force detection device will detect the hydraulic braking force F in real time. ht The data is transmitted to the braking consistency control device, which then determines the braking consistency control device based on the real-time hydraulic braking force F. ht And target hydraulic braking force F h The corresponding hydraulic braking force response curve F h (t) Calculate the error and determine whether the hydraulic braking force response curve F needs to be adjusted. h (t) is used for correction control.

4. The control method of the braking mode switching consistency control system according to claim 3, characterized in that, Step 2) specifically refers to: The target hydraulic braking force is F h The dynamic response curve of the hydraulic braking force corresponding to the target hydraulic braking force is F. h (t), then the motor power compensation value is ΔF m =F h -F h (t).

5. The control method of the braking mode switching consistency control system according to claim 3, characterized in that, Step 3) specifically refers to: The electric motor power compensation value is ΔF m The target electric motor's power is F m The dynamic response curve of the electric motor is F. m (t)=F m +ΔF m .

6. The control method of the braking mode switching consistency control system according to claim 3, characterized in that, Step 5) specifically includes: 51) Based on the real-time hydraulic braking force F ht And target hydraulic braking force F h The corresponding hydraulic braking force response curve F h (t) Calculate the hydraulic braking force error Δ t Real-time hydraulic braking force F ht Corresponding dynamic response curve F of hydraulic braking force h The hydraulic braking force at the same moment (t) is F, and the error of the hydraulic braking force is calculated in real time. If the hydraulic braking force error is less than or equal to 2%, the requirement is met; otherwise, the requirement is not met. 52) If all hydraulic braking force errors meet the requirements, the hydraulic braking force response curve corresponding to the target braking force remains unchanged; if a hydraulic braking force error Δ exists... t If the requirements are not met, calculate the hydraulic braking force correction value. The hydraulic braking force correction value is substituted into the hydraulic braking force response curve for correction and optimization. The corresponding hydraulic braking force at the same moment becomes F', F'=F+ΔF.

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