New energy vehicle electric braking and parking method and system based on slope sensor

Abstract

The present invention discloses an electric braking and parking method and system for a new energy vehicle based on a slope sensor. The braking method includes: obtaining a brake pedal travel signal, a road slope signal measured by a slope sensor, and a speed signal of a drive motor; obtaining an adjustment coefficient based on the brake pedal travel signal, and obtaining a preload torque based on the slope signal; obtaining a torque instruction based on the adjustment coefficient and the preload torque, and comparing the torque instruction with the maximum allowable torque at the current motor speed to obtain an output torque instruction; and controlling the drive motor based on the output torque instruction so that the vehicle enters a braking state. The present invention can utilize electric braking as much as possible to achieve vehicle braking, fully recover energy, and improve cruising range; reduce brake pad wear and increase the service life of the brake pad. Parking using a combination of preload torque and speed mode can improve response speed and stability.

Description

Technical Field

[0001] The present invention relates to the technical field of new energy vehicles, and in particular to a slope sensor-based electric braking and parking method and system for a new energy vehicle. Background Art

[0002] The statements in this section merely provide background information related to the present invention and do not necessarily constitute prior art.

[0003] New energy vehicles are cars that use electricity as their power source and are generally composed of components such as batteries, battery management systems, drive motors, motor controllers and vehicle controllers.

[0004] The braking and parking of new energy vehicles usually adopt a combination of electric braking and hydraulic braking. The ratio of electric braking to hydraulic braking is distributed through the depth of the brake pedal to achieve a good braking effect.

[0005] However, due to the presence of hydraulic brakes, the performance of electric brakes cannot be fully utilized, reducing the efficiency of electric brake energy recovery. Therefore, some studies have proposed relying solely on electric brakes to achieve braking and stopping. However, using only electric brakes to stop the vehicle on a slope can easily cause the vehicle to shake back and forth, resulting in poor parking performance. Summary of the Invention

[0006] In order to solve the above problems, the present invention proposes an electric braking and parking method and system for new energy vehicles based on a slope sensor. The slope value collected by the slope sensor is introduced into the electric braking control to achieve stable parking under various road conditions, improve energy recovery efficiency, and enhance driving experience.

[0007] In some embodiments, the following technical solutions are adopted:

[0008] A new energy vehicle electric braking method based on a slope sensor, comprising:

[0009] Acquire a brake pedal travel signal, a road slope signal measured by a slope sensor, and a speed signal of a drive motor;

[0010] obtaining an adjustment coefficient according to the brake pedal travel signal, and obtaining a preload torque according to the slope signal;

[0011] obtaining a torque command based on the adjustment coefficient and the preload torque, and comparing the torque command with the maximum allowable torque at the current motor speed to obtain an output torque command;

[0012] The drive motor is controlled based on the output torque command, so that the vehicle enters a braking state.

[0013] The torque command is obtained based on the adjustment coefficient and the preload torque, and the torque command is compared with the maximum allowable torque at the current motor speed to obtain the output torque command, specifically:

[0014] The adjustment coefficient is multiplied by the preload torque to obtain a torque instruction; if the torque instruction is less than the maximum allowable torque at the current motor speed, the torque instruction is used as the output torque instruction; if the torque instruction is greater than the maximum allowable torque at the current motor speed, the maximum allowable torque is used as the output torque instruction.

[0015] In other embodiments, the following technical solutions are adopted:

[0016] A new energy vehicle electric braking system based on a slope sensor, comprising:

[0017] A data acquisition module is used to obtain a brake pedal travel signal, a road slope signal measured by a slope sensor, and a speed signal of a drive motor;

[0018] a first data processing module, configured to obtain an adjustment coefficient according to the brake pedal travel signal and obtain a preload torque according to the slope signal;

[0019] a second data processing module, configured to obtain a torque command based on the adjustment coefficient and the preload torque, and compare the torque command with the maximum allowable torque at the current motor speed to obtain an output torque command;

[0020] The drive motor control module is used to control the drive motor based on the output torque instruction so that the vehicle enters a braking state.

[0021] In other embodiments, the following technical solutions are adopted:

[0022] A parking method for a new energy vehicle based on a slope sensor, comprising:

[0023] Obtaining the brake pedal travel signal, the road slope signal measured by the slope sensor, and the speed signal of the drive motor; when the speed of the drive motor is lower than the set threshold, the motor controller operates in the speed mode with the target speed being zero;

[0024] obtaining an adjustment coefficient according to the brake pedal travel signal, and obtaining a preload torque according to the slope signal;

[0025] Based on the adjustment coefficient, the preload torque, and the difference between the speed of the drive motor and the target speed, a torque command is obtained; and the torque command is compared with the maximum allowable torque at the current motor speed to obtain an output torque command;

[0026] The drive motor is controlled based on the output torque command so that the vehicle enters a parking state.

[0027] The torque command is obtained based on the adjustment coefficient, the preload torque, and the difference between the speed of the drive motor and the target speed, specifically:

[0028] Obtaining a first torque command based on a product of the adjustment coefficient and the preload torque;

[0029] Obtaining a second torque command based on a difference between the rotational speed of the drive motor and the target rotational speed;

[0030] The first torque command and the second torque command are added together to obtain a third torque command, that is, a torque command.

[0031] In other embodiments, the following technical solutions are adopted:

[0032] A new energy vehicle parking system based on a slope sensor, comprising:

[0033] A data acquisition module is used to obtain the brake pedal travel signal, the road slope signal measured by the slope sensor, and the speed signal of the drive motor; when the speed of the drive motor is lower than a set threshold, the motor controller operates in a speed mode with a target speed of zero;

[0034] a first data processing module, configured to obtain an adjustment coefficient according to the brake pedal travel signal and obtain a preload torque according to the slope signal;

[0035] a second data processing module, configured to obtain a torque command based on the adjustment coefficient, the preload torque, and the difference between the rotational speed of the drive motor and the target rotational speed; and compare the torque command with the maximum allowable torque at the current motor rotational speed to obtain an output torque command;

[0036] The drive motor control module is used to control the drive motor based on the output torque instruction so that the vehicle enters a parking state.

[0037] In other embodiments, the following technical solutions are adopted:

[0038] A new energy vehicle, comprising:

[0039] Brake pedal, used to obtain vehicle braking information and transmit it to the vehicle controller;

[0040] Slope sensor, used to obtain road slope information and transmit it to the vehicle controller;

[0041] The vehicle controller is used to output torque instructions based on the received information and control the operation of the motor controller;

[0042] The motor controller is used to control the operation of the drive motor according to the received output torque command to achieve braking or parking of the vehicle.

[0043] Compared with the prior art, the present invention has the following beneficial effects:

[0044] (1) The present invention obtains an output torque instruction to the motor controller based on the brake pedal travel signal, the road slope signal measured by the slope sensor and the speed signal of the drive motor, thereby controlling the drive motor to output the corresponding torque; the preload torque, i.e., the feedforward torque, is obtained by looking up the table according to the slope value. The response speed is faster and the accuracy is higher than that of the simple PI control. When entering the parking condition, the torque mode is switched to the speed mode. In the speed mode, the parking stability is better.

[0045] (2) The present invention can maximize the use of electric braking to achieve vehicle braking, fully recover energy, and improve driving range; reduce brake pad wear and increase brake pad service life. The combination of preload torque and speed mode can improve response speed and stability.

[0046] Other features and advantages of additional aspects of the present invention will be given in part in the following description and in part will become obvious from the following description or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0047] Figure 1 This is a flow chart of a new energy vehicle electric braking method based on a slope sensor in an embodiment of the present invention;

[0048] Figure 2 Schematic diagram of motor controller mode switching in an embodiment of the present invention;

[0049] Figure 3 This is a flow chart of a new energy vehicle parking method based on a slope sensor in an embodiment of the present invention;

[0050] Figure 4 Schematic diagram of a basic control system for a new energy vehicle in an embodiment of the present invention. DETAILED DESCRIPTION

[0051] It should be noted that the following detailed description is illustrative and is intended to provide further explanation of the present application. Unless otherwise specified, all technical and scientific terms used in the present invention have the same meaning as commonly understood by those skilled in the art to which the present application belongs.

[0052] It should be noted that the terms used herein are only for describing specific embodiments and are not intended to limit the exemplary embodiments according to the present application. As used herein, unless the context clearly indicates otherwise, the singular form is also intended to include the plural form. In addition, it should be understood that when the terms "comprise" and / or "include" are used in this specification, they indicate the presence of features, steps, operations, devices, components and / or combinations thereof.

[0053] Example 1

[0054] In one or more embodiments, a slope sensor-based electric braking method for a new energy vehicle is disclosed, comprising the following steps:

[0055] (1) Obtaining a brake pedal travel signal, a road slope signal measured by a slope sensor, and a speed signal of a drive motor;

[0056] (2) obtaining an adjustment coefficient based on the brake pedal travel signal and obtaining a preload torque based on the slope signal;

[0057] (3) obtaining a torque command based on the adjustment coefficient and the preload torque, and comparing the torque command with the maximum allowable torque at the current motor speed to obtain an output torque command;

[0058] (4) The drive motor is controlled based on the output torque command so that the vehicle enters a braking state.

[0059] In this embodiment, the adjustment coefficient is obtained by looking up the table based on the brake pedal travel signal; the brake pedal travel signal represents a range of 0% to 100%, and the adjustment coefficient represents a range of 0 to 1; the adjustment coefficient is negatively correlated with the brake pedal travel signal.

[0060] According to the road slope information, the preload torque is obtained by looking up the table;

[0061] After multiplying the adjustment coefficient and the preload torque, compare it with the maximum allowable torque at the current motor speed. If it is less than or equal to the maximum allowable torque, the output torque command is equal to the torque obtained by adding the two. If it is greater than the maximum allowable torque, the output torque command is limited to the maximum allowable torque.

[0062] The output torque command is transmitted to the motor controller. After receiving the torque command, the motor controller controls the drive motor to put the vehicle into a braking state.

[0063] Specifically, combined Figure 1 , the calculation module 1-1 collects the brake pedal stroke signal sent from the brake pedal and outputs the adjustment coefficient K1;

[0064] The calculation module 1-2 collects the slope signal from the slope sensor, looks up the table and outputs the preload torque instruction T1;

[0065] The outputs K1 and T1 of the above two parts are input to the calculation module 1-3, and the two are multiplied to obtain the processed torque command T2;

[0066] After the limiting operation of the operation modules 1-4, T2 is equal to the maximum torque T allowed at the current speed. max Compare, if T2 is less than or equal to T max , then the output T3 = T2; otherwise the output T3 = T max ;

[0067] T3 outputs six PWM signals to the drive motor through operation modules 1-5, controlling the drive motor to operate in a braking condition.

[0068] Example 2

[0069] In one or more embodiments, a method is disclosed for driving a motor controller to enter a speed mode and execute a parking control system, specifically including:

[0070] A data acquisition module is used to obtain a brake pedal travel signal, a road slope signal measured by a slope sensor, and a speed signal of a drive motor;

[0071] a first data processing module, configured to obtain an adjustment coefficient according to the brake pedal travel signal and obtain a preload torque according to the slope signal;

[0072] a second data processing module, configured to obtain a torque command based on the adjustment coefficient and the preload torque, and compare the torque command with the maximum allowable torque at the current motor speed to obtain an output torque command;

[0073] The drive motor control module is used to control the drive motor based on the output torque instruction so that the vehicle enters a braking state.

[0074] It should be noted that the specific implementation process of each of the above modules has been described in detail in Example 1 and will not be described in detail here.

[0075] Example 3

[0076] In one or more embodiments, a parking method for a new energy vehicle based on a slope sensor is disclosed, comprising the following steps:

[0077] (1) Obtaining a brake pedal travel signal, a road slope signal measured by a slope sensor, and a speed signal of a drive motor; when the speed of the drive motor is lower than a set threshold, the motor controller operates in a speed mode with a target speed of zero;

[0078] (2) obtaining an adjustment coefficient according to the brake pedal travel signal and obtaining a preload torque according to the slope signal;

[0079] (3) obtaining a torque command based on the adjustment coefficient, the preload torque, and the difference between the speed of the drive motor and the target speed; and comparing the torque command with the maximum allowable torque at the current motor speed to obtain an output torque command;

[0080] (4) The drive motor is controlled based on the output torque command so that the vehicle enters a parking state.

[0081] Specifically, in parking conditions, the target speed of the drive motor is 0 rpm. The motor controller uses a table lookup based on the slope signal and the brake pedal travel signal to determine the corresponding preload torque. It then controls the drive motor to output the corresponding torque and performs PI regulation. When the drive motor speed stabilizes at 0 rpm, the vehicle is parked.

[0082] Combine Figure 2 When the speed of the drive motor is lower than the set threshold, the motor controller automatically switches from torque mode to speed mode. The specific process is as follows:

[0083] 1) When the current motor speed is less than the set speed N, the motor controller enters the speed mode, and the motor execution torque maintains the output torque at the previous moment to maintain the current state stable.

[0084] 2) In speed mode, the motor controller's control target is the motor speed. In parking mode, the target speed is set to 0 rpm.

[0085] 3) Perform preload torque and PI adjustment to control the motor to run at 0 rpm to achieve stable parking.

[0086] In this embodiment, the drive motor controller enters the speed mode and executes the parking control algorithm. Figure 3 The specific process is as follows:

[0087] 1) The control purpose in the speed mode is to stop the vehicle, so the speed command N1 = 0;

[0088] 2) The speed sensor collects the current speed N2 from the drive motor;

[0089] 3) Subtract the two speeds to obtain the speed difference N3;

[0090] 4) The calculation module 2-1 receives the brake pedal travel signal and outputs the adjustment coefficient K2;

[0091] 5) The calculation module 2-2 receives the slope signal from the slope sensor and outputs the preload torque instruction T5;

[0092] 6) The calculation module 2-3 multiplies the outputs of step 4) and step 5) above and outputs torque T6;

[0093] 7) The calculation module 2-4 receives the speed difference N3, performs PI calculation, and outputs the torque command T7;

[0094] 8) adding the torque T6 output in step 6) and the torque T7 output in step 7) to obtain a torque command T8;

[0095] 9) The torque command T8 is calculated by the limiting operation of the operation module 2-5 and the maximum torque T allowed at the current speed. max Compare, if T8 is less than or equal to T max , then the output T9=T8; otherwise the output T9=T max ;

[0096] 10) T9 outputs six PWM signals to the drive motor through the calculation modules 2-6, controlling the drive motor speed to gradually decrease to 0 rpm, thereby controlling the vehicle to stop.

[0097] Example 4

[0098] In one or more embodiments, a new energy vehicle parking system based on a slope sensor is disclosed, specifically comprising:

[0099] A data acquisition module is used to obtain the brake pedal travel signal, the road slope signal measured by the slope sensor, and the speed signal of the drive motor; when the speed of the drive motor is lower than a set threshold, the motor controller operates in a speed mode with a target speed of zero;

[0100] a first data processing module, configured to obtain an adjustment coefficient according to the brake pedal travel signal and obtain a preload torque according to the slope signal;

[0101] a second data processing module, configured to obtain a torque command based on the adjustment coefficient, the preload torque, and the difference between the rotational speed of the drive motor and the target rotational speed; and compare the torque command with the maximum allowable torque at the current motor rotational speed to obtain an output torque command;

[0102] The drive motor control module is used to control the drive motor based on the output torque instruction so that the vehicle enters a parking state.

[0103] It should be noted that the specific implementation process of each of the above modules has been described in detail in Example 1 and will not be described in detail here.

[0104] Example 5

[0105] In one or more embodiments, a new energy vehicle is disclosed, Figure 4 , specifically including:

[0106] Brake pedal, used to obtain vehicle braking information and transmit it to the vehicle controller;

[0107] Slope sensor, used to obtain road slope information and transmit it to the vehicle controller;

[0108] The vehicle controller is used to output torque instructions based on the received information and control the operation of the motor controller;

[0109] The motor controller is used to control the operation of the drive motor according to the received output torque command to achieve braking or parking of the vehicle.

[0110] Among them, the specific process of the vehicle controller outputting a torque instruction based on the received information to control the motor controller to achieve vehicle braking or parking has been described in detail in Example 1 or Example 3 and will not be detailed here.

[0111] Although the above describes the specific embodiments of the present invention in conjunction with the accompanying drawings, it is not intended to limit the scope of protection of the present invention. Those skilled in the art should understand that various modifications or variations that can be made by those skilled in the art on the basis of the technical solution of the present invention without any creative work are still within the scope of protection of the present invention.

Claims

1. A parking method for a new energy vehicle based on a slope sensor, characterized in that: include: Acquire a brake pedal travel signal, a road slope signal measured by a slope sensor, and a speed signal of a drive motor; When the speed of the drive motor is lower than the set threshold, the motor controller works in the speed mode and the target speed is zero; obtaining an adjustment coefficient according to the brake pedal travel signal, and obtaining a preload torque according to the slope signal; Based on the adjustment coefficient, the preload torque, and the difference between the speed of the drive motor and the target speed, a torque command is obtained; and the torque command is compared with the maximum allowable torque at the current motor speed to obtain an output torque command; controlling the drive motor based on the output torque command so that the vehicle enters a parking state; When the speed of the drive motor is lower than the set threshold, the motor controller automatically switches from torque mode to speed mode. The specific process is as follows: When the current motor speed is less than the set speed N, the motor controller enters the speed mode, and the motor execution torque maintains the output torque at the previous moment to maintain the current state stable; In the speed mode, the control target of the motor controller is the motor speed. In the parking condition, the target speed is set to 0 rpm. Perform preload torque and PI adjustment to control the motor to run at 0rpm, achieving stable parking.

2. A parking method for a new energy vehicle based on a slope sensor as claimed in claim 1, characterized in that: Based on the adjustment coefficient, the preload torque, and the difference between the speed of the drive motor and the target speed, a torque command is obtained, specifically: Obtaining a first torque command based on a product of the adjustment coefficient and the preload torque; Obtaining a second torque command based on a difference between the rotational speed of the drive motor and the target rotational speed; The first torque command and the second torque command are added together to obtain a third torque command, that is, a torque command.

3. The parking method for a new energy vehicle based on a slope sensor according to claim 1, characterized in that: The torque command is compared with the maximum allowable torque at the current motor speed to obtain the output torque command, specifically: If the torque command is less than the maximum allowable torque at the current motor speed, the torque command is used as the output torque command; if the torque command is greater than the maximum allowable torque at the current motor speed, the maximum allowable torque is used as the output torque command.

4. A new energy vehicle parking system based on a slope sensor, characterized in that: include: A data acquisition module is used to obtain a brake pedal travel signal, a road slope signal measured by a slope sensor, and a speed signal of a drive motor; When the speed of the drive motor is lower than the set threshold, the motor controller works in the speed mode and the target speed is zero; a first data processing module, configured to obtain an adjustment coefficient according to the brake pedal travel signal and obtain a preload torque according to the slope signal; a second data processing module, configured to obtain a torque command based on the adjustment coefficient, the preload torque, and the difference between the rotational speed of the drive motor and the target rotational speed; and compare the torque command with the maximum allowable torque at the current motor rotational speed to obtain an output torque command; a drive motor control module, configured to control the drive motor based on the output torque command so that the vehicle enters a parking state; When the speed of the drive motor is lower than the set threshold, the motor controller automatically switches from torque mode to speed mode. The specific process is as follows: When the current motor speed is less than the set speed N, the motor controller enters the speed mode, and the motor execution torque maintains the output torque at the previous moment to maintain the current state stable; In the speed mode, the control target of the motor controller is the motor speed. In the parking condition, the target speed is set to 0 rpm. Perform preload torque and PI adjustment to control the motor to run at 0rpm, achieving stable parking.

5. A new energy vehicle, characterized in that: A parking method for a new energy vehicle based on a slope sensor as claimed in any one of claims 1 to 3 is adopted, comprising: Brake pedal, used to obtain vehicle braking information and transmit it to the vehicle controller; Slope sensor, used to obtain road slope information and transmit it to the vehicle controller; The vehicle controller is used to output torque instructions based on the received information and control the operation of the motor controller; The motor controller is used to control the operation of the drive motor according to the received output torque command to achieve braking or parking of the vehicle.

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