An AMT countershaft brake control system, method and apparatus

Abstract

The embodiment of the application provides an AMT auxiliary shaft brake control system, method and device, to solve the technical problem that the opening time of the electromagnetic valve is difficult to accurately calculate when the existing AMT auxiliary shaft brake, which can easily cause the auxiliary shaft brake to be insufficient or too much, directly leading to the shift time being too long or the shift impact. The system comprises a gearbox oil temperature sensor, a gearbox controller, a PWM intake electromagnetic valve, an exhaust electromagnetic valve, an auxiliary shaft brake pad, an auxiliary shaft and an auxiliary shaft sensor; wherein the auxiliary shaft brake pad is connected to the PWM intake electromagnetic valve and the exhaust electromagnetic valve respectively, the opening degree of the PWM intake electromagnetic valve can be adjusted to change the intake amount and provide different brake forces, and the exhaust electromagnetic valve is used for exhaust pressure relief and brake release. The auxiliary shaft brake can be accurately controlled to avoid insufficient or excessive braking and improve the shift performance.

Description

Technical Field

[0001] This application relates to the field of AMT control technology, and in particular to an AMT countershaft braking control system, method and device. Background Technology

[0002] Currently, most AMT (Automated Manual Transmission) systems use sliding gear sleeve shifting. Shifting requires first reducing the countershaft speed, and the shift is completed when the gear sleeve reaches the appropriate speed difference. To shorten shift time, a countershaft brake is used. Once the brake is engaged, a solenoid valve is activated, and compressed gas enters to push the brake pads, quickly braking the countershaft to the target speed. However, in actual control, due to the complexity of the transmission system, the solenoid valve opening time is difficult to calculate accurately, easily leading to insufficient or excessive countershaft braking. This directly results in excessively long shift times or shift shocks, affecting vehicle driving comfort. Summary of the Invention

[0003] This application provides an AMT countershaft braking control system, method, and apparatus to solve the technical problem that the opening time of the solenoid valve is difficult to calculate accurately when the countershaft is braked in an existing AMT, which easily leads to insufficient or excessive braking of the countershaft, directly resulting in excessively long shifting time or shifting shock.

[0004] On one hand, this application provides an AMT countershaft braking control system, the system including: a transmission oil temperature sensor, a transmission controller, a PWM intake solenoid valve, an exhaust solenoid valve, a countershaft brake pad, a countershaft, and a countershaft sensor; wherein, the countershaft brake pad is connected to the PWM intake solenoid valve and the exhaust solenoid valve respectively, the opening of the PWM intake solenoid valve is adjustable to change the intake volume and provide different braking forces, and the exhaust solenoid valve is used for exhaust pressure relief and release braking.

[0005] On the other hand, this application also provides an AMT countershaft braking control method, the method comprising: acquiring the current countershaft speed, transmission oil temperature and target countershaft speed; determining whether the speed difference is greater than a preset threshold based on PID control; if the speed difference is greater than the preset threshold, activating braking; if the speed difference is less than the preset threshold, deactivating braking and venting pressure.

[0006] In one implementation of this application, the PID control process specifically involves: establishing a PID control model for the secondary shaft braking; inputting the speed difference between the current speed of the secondary shaft and the target speed of the secondary shaft; and outputting the percentage value that the current PWM intake solenoid valve needs to open after PID calculation.

[0007] In one implementation of this application, the process of calculating and outputting the percentage value that the current PWM intake solenoid valve needs to be opened via PID control is specifically as follows:

[0008] The PID parameters are dynamically selected through a two-dimensional interpolation module; wherein the input of the two-dimensional interpolation module is the current required braking amount of the countershaft and the current oil temperature of the transmission, and the output is the PID parameters.

[0009] In one implementation of this application, the method further includes:

[0010] Collect braking signals from the brake pads;

[0011] Based on the brake pad braking signal, the wear condition of the brake pad is calculated;

[0012] After the brake pad wear reaches a preset threshold, wear compensation corresponding to the brake pad wear is added to the PID calculation.

[0013] In one implementation of this application, the process of calculating the wear of the brake pads is as follows:

[0014] Calculate the braking slope of the brake pads under specified conditions;

[0015] Determine the wear level of the brake pads based on the current braking slope.

[0016] In one implementation of this application, the method further includes:

[0017] Set the brake release threshold;

[0018] When the speed difference is less than the brake release threshold, the PWM intake solenoid valve is closed and the exhaust valve is opened to release the brake.

[0019] In addition, this application also provides an AMT countershaft braking control device, the device comprising:

[0020] The signal acquisition module is used to acquire the current speed of the countershaft, the transmission oil temperature, and the target speed of the countershaft.

[0021] The speed difference determination module is used to determine whether the speed difference is greater than a preset threshold based on PID control.

[0022] The braking control module is used to activate braking when the speed difference is greater than a preset threshold, and to deactivate braking and release exhaust pressure when the speed difference is less than the preset threshold.

[0023] In one implementation of this application, the speed difference determination module includes:

[0024] The PID model building submodule is used to build the PID control model for the secondary shaft braking.

[0025] The speed input submodule is used to input the speed difference between the current speed of the secondary shaft and the target speed of the secondary shaft;

[0026] The solenoid valve opening calculation submodule is used to calculate and output the percentage value that the current PWM intake solenoid valve needs to open, based on PID calculation.

[0027] This application provides an AMT countershaft braking control system, method, and apparatus. It utilizes PID dynamic control of the PWM solenoid valve opening based on the difference between the current and target countershaft speeds to brake the countershaft. A threshold is set to ensure improved response speed while avoiding over-braking. To address the decrease in braking performance due to brake pad wear, the current braking performance is calculated and statistically analyzed in real time, and wear compensation is applied to the braking output. This allows for precise control of the countershaft braking, preventing under-braking or over-braking and improving shifting performance. Attached Figure Description

[0028] The accompanying drawings, which are included to provide a further understanding of this application and form part of this application, illustrate exemplary embodiments and are used to explain this application, but do not constitute an undue limitation of this application. In the drawings:

[0029] Figure 1 A block diagram of an AMT countershaft braking control system provided in this application embodiment;

[0030] Figure 2 A flowchart of an AMT countershaft braking control method provided in this application embodiment;

[0031] Figure 3 A block diagram of an AMT countershaft braking control device provided in this application embodiment;

[0032] Figure 4 This is a control logic diagram of an embodiment of this application. Detailed Implementation

[0033] To make the objectives, technical solutions, and advantages of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments and corresponding drawings. Obviously, the described embodiments are only a part of the embodiments of this application, and not all of them. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0034] This application provides an AMT countershaft braking control system, method, and apparatus to solve the technical problem that the opening time of the solenoid valve is difficult to calculate accurately when the countershaft is braked in an existing AMT, which easily leads to insufficient or excessive braking of the countershaft, directly resulting in excessively long shifting time or shifting shock.

[0035] The technical solutions proposed in the embodiments of this application will be described in detail below with reference to the accompanying drawings.

[0036] Figure 1 This is a block diagram of an AMT countershaft braking control system provided in an embodiment of this application. Figure 1 As shown, the system includes a transmission oil temperature sensor, a transmission controller, a PWM intake solenoid valve, an exhaust solenoid valve, a countershaft brake pad, a countershaft, and a countershaft sensor. The countershaft brake pad is connected to the PWM intake solenoid valve and the exhaust solenoid valve respectively. The opening of the PWM intake solenoid valve is adjustable to change the intake volume and provide different braking forces. The exhaust solenoid valve is used for exhaust pressure relief and brake release.

[0037] The above describes an AMT countershaft braking control system provided by an embodiment of this application. Based on the same inventive concept, this application also provides an AMT countershaft braking control method. Figure 2 A flowchart of an AMT countershaft braking control method provided in this application embodiment is shown below. Figure 2 As shown, the system mainly includes:

[0038] Step 201: Obtain the current speed of the countershaft, the transmission oil temperature, and the target speed of the countershaft.

[0039] Step 202: Based on PID control, determine whether the speed difference is greater than a preset threshold; if the speed difference is greater than the preset threshold, activate braking; if the speed difference is less than the preset threshold, deactivate braking and release exhaust pressure.

[0040] Furthermore, the PID control process specifically involves: establishing a PID control model for the secondary shaft braking; inputting the speed difference between the current speed of the secondary shaft and the target speed of the secondary shaft; and outputting the percentage value that the current PWM intake solenoid valve needs to open after PID calculation.

[0041] Furthermore, the process of calculating and outputting the percentage value that the current PWM intake solenoid valve needs to open via PID is as follows:

[0042] The PID parameters are dynamically selected through a two-dimensional interpolation module; wherein the input of the two-dimensional interpolation module is the current required braking amount of the countershaft and the current oil temperature of the transmission, and the output is the PID parameters.

[0043] Furthermore, the method also includes:

[0044] Collect braking signals from the brake pads;

[0045] Based on the brake pad braking signal, the wear condition of the brake pad is calculated;

[0046] After the brake pad wear reaches a preset threshold, wear compensation corresponding to the brake pad wear is added to the PID calculation.

[0047] Furthermore, the process of calculating brake pad wear is as follows:

[0048] Calculate the braking slope of the brake pads under specified conditions;

[0049] Determine the wear level of the brake pads based on the current braking slope.

[0050] Furthermore, the method also includes:

[0051] Set the brake release threshold;

[0052] When the speed difference is less than the brake release threshold, the PWM intake solenoid valve is closed and the exhaust valve is opened to release the brake.

[0053] In addition, this application also provides an AMT countershaft braking control device, such as Figure 3 As shown, the device includes:

[0054] The signal acquisition module 301 is used to acquire the current speed of the countershaft, the gearbox oil temperature, and the target speed of the countershaft.

[0055] The speed difference determination module 302 is used to determine whether the speed difference is greater than a preset threshold based on PID control.

[0056] The braking control module 303 is used to activate braking when the speed difference is greater than a preset threshold, and to deactivate braking and release pressure when the speed difference is less than the preset threshold.

[0057] Furthermore, the speed difference determination module includes:

[0058] The PID model building submodule is used to build the PID control model for the secondary shaft braking.

[0059] The speed input submodule is used to input the speed difference between the current speed of the secondary shaft and the target speed of the secondary shaft;

[0060] The solenoid valve opening calculation submodule is used to calculate and output the percentage value that the current PWM intake solenoid valve needs to open, based on PID calculation.

[0061] The control logic diagram of this application is as follows: Figure 4As shown, the PID parameters in the auxiliary shaft braking control unit are dynamically adjusted using a two-dimensional linear interpolation module during the control process. Since the auxiliary shaft braking effect varies with different gearbox temperatures, the two-dimensional linear interpolation module takes the auxiliary shaft speed difference and the current gearbox temperature as inputs and outputs the PID parameters at that moment. When the speed difference is large and the gearbox temperature is high, resulting in slightly lower auxiliary shaft braking performance, the output PID parameters cause the PWM solenoid valve to open larger, achieving rapid braking; when the speed difference is small, the PID parameters are selected to decrease the PWM solenoid valve opening, performing micro-braking. The interpolation module is calibrated and adjusted according to the actual situation. To avoid overshoot of the PWM solenoid valve under PID control, it is set that when the current auxiliary shaft speed difference is less than a set threshold, the PWM intake solenoid valve is immediately closed and the exhaust valve is opened to release pressure and prevent over-braking.

[0062] The temperature and PWM solenoid valve opening conditions for calculating the braking slope are set, such as the braking slope at 70% PWM solenoid valve opening when the transmission oil temperature is 50℃, as the standard for calculating the countershaft braking slope. The braking slope calculated at time k is x(k). The slope after multiple measurements and filtering is selected and recorded as the current braking effect of the brake: y(k) = b0x(k) + b1x(k-1) + b2x(k-2) + L, where the filtering order and coefficients are calibrated according to the actual situation. During braking, the braking output is compensated according to the braking slope range after brake pad wear.

[0063] This application provides an AMT countershaft braking control system, method, and apparatus. It utilizes PID dynamic control of the PWM solenoid valve opening based on the difference between the current and target countershaft speeds to brake the countershaft. A threshold is set to ensure improved response speed while avoiding over-braking. To address the decrease in braking performance due to brake pad wear, the current braking performance is calculated and statistically analyzed in real time, and wear compensation is applied to the braking output. This allows for precise control of the countershaft braking, preventing under-braking or over-braking and improving shifting performance.

[0064] The various embodiments in this application are described in a progressive manner. Similar or identical parts between embodiments can be referred to mutually. Each embodiment focuses on describing the differences from other embodiments. In particular, the device embodiments are basically similar to the method embodiments, so the description is relatively simple; relevant parts can be referred to the descriptions of the method embodiments.

[0065] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0066] The above description is merely an embodiment of this application and is not intended to limit this application. Various modifications and variations can be made to this application by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principle of this application should be included within the scope of the claims of this application.

Claims

1. A method for controlling the braking of an AMT (Automated Manual Transmission) sub-shaft, characterized in that, An AMT (Automated Manual Transmission) countershaft braking control system is provided, comprising: a transmission oil temperature sensor, a transmission controller, a PWM (Pulse Width Modulation) intake solenoid valve, an exhaust solenoid valve, countershaft brake pads, a countershaft, and a countershaft sensor; wherein the countershaft brake pads are respectively connected to the PWM intake solenoid valve and the exhaust solenoid valve, the opening of the PWM intake solenoid valve is adjustable to change the intake volume and provide different braking forces, and the exhaust solenoid valve is used for exhaust pressure relief and brake release; the method includes: Obtain the current countershaft speed, transmission oil temperature, and target countershaft speed; Based on PID control, it is determined whether the speed difference is greater than a preset threshold. The PID control process is as follows: establishing a PID control model for the secondary shaft braking; inputting the speed difference between the current speed of the secondary shaft and the target speed of the secondary shaft; calculating and outputting the percentage value that the current PWM intake solenoid valve needs to open through PID calculation; the process of calculating and outputting the percentage value that the current PWM intake solenoid valve needs to open through PID calculation is as follows: dynamically selecting PID parameters through a two-dimensional interpolation module; wherein, the input of the two-dimensional interpolation module is the current braking amount required for the secondary shaft and the current oil temperature of the transmission, and the output is the PID parameters. If the speed difference is greater than a preset threshold, braking is activated; if the speed difference is less than the preset threshold, braking is deactivated and exhaust pressure is released. The method further includes: acquiring brake pad braking signals; calculating brake pad wear based on the brake pad braking signals; and adding wear compensation corresponding to the brake pad wear to the PID calculation after the brake pad wear reaches a preset threshold.

2. The AMT countershaft braking control method according to claim 1, characterized in that, The process of calculating brake pad wear is as follows: Calculate the braking slope of the brake pads under specified conditions; Determine the wear level of the brake pads based on the current braking slope.

3. The AMT countershaft braking control method according to claim 1, characterized in that, The method further includes: Set the brake release threshold; When the speed difference is less than the brake release threshold, the PWM intake solenoid valve is closed and the exhaust valve is opened to release the brake.

4. An AMT (Automated Manual Transmission) secondary shaft braking control device, characterized in that, An AMT (Automated Manual Transmission) countershaft braking control system is provided. The system includes: a transmission oil temperature sensor, a transmission controller, a PWM (Pulse Width Modulation) intake solenoid valve, an exhaust solenoid valve, countershaft brake pads, a countershaft, and a countershaft sensor. The countershaft brake pads are connected to both the PWM intake solenoid valve and the exhaust solenoid valve. The opening of the PWM intake solenoid valve is adjustable to change the intake volume and provide different braking forces. The exhaust solenoid valve is used for exhaust pressure relief and brake release. The device includes: The signal acquisition module is used to acquire the current speed of the countershaft, the transmission oil temperature, and the target speed of the countershaft; it is also used to acquire the brake pad braking signal; based on the brake pad braking signal, it calculates the wear condition of the brake pad; after the brake pad wear reaches a preset threshold, it adds wear compensation corresponding to the brake pad wear to the PID calculation; The speed difference determination module is used to determine whether the speed difference is greater than a preset threshold based on PID control. The speed difference determination module includes: a PID model establishment submodule for establishing a PID control model for the secondary shaft braking; a speed input submodule for inputting the speed difference between the current speed and the target speed of the secondary shaft; and a solenoid valve opening calculation submodule for calculating and outputting the percentage value that the current PWM intake solenoid valve needs to open based on PID calculation. Specifically, the process of calculating and outputting the percentage value that the current PWM intake solenoid valve needs to open based on PID calculation involves dynamically selecting PID parameters through a two-dimensional interpolation module. The two-dimensional interpolation module takes as input the current required braking amount of the secondary shaft and the current oil temperature of the transmission, and outputs PID parameters. The braking control module is used to activate braking when the speed difference is greater than a preset threshold, and to deactivate braking and release exhaust pressure when the speed difference is less than the preset threshold.

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