An adaptive starting control method for a commercial vehicle equipped with an AMT on an icy and snowy road

Abstract

This invention relates to a start-up control method for commercial vehicles equipped with AMT (Automated Manual Transmission), specifically an adaptive start-up control method for AMT-equipped commercial vehicles on icy and snowy roads. This method addresses the problems of existing AMT-equipped vehicles having fixed start-up control strategies on icy and snowy roads, failing to adapt to different adhesion conditions, resulting in slippage, unevenness, and poor adaptability. The invention includes: constructing a start-up control mapping table and a fuzzy rule base; obtaining basic start-up control parameters after recognizing a start-up request; determining the slippage trend by comparing wheel speeds at the moment of clutch engagement; if a slippage trend exists, estimating or retrieving historical peak adhesion coefficients to set a target slip ratio; calculating the actual slip ratio and its deviation and rate of change in real time, querying the fuzzy rule base to dynamically output clutch engagement speed correction and engine torque correction, and making real-time corrections to the basic parameters; repeating the above closed-loop control until a smooth start; and finally updating and storing the peak adhesion coefficient for subsequent start-up use.

Description

Technical Field

[0001] This invention relates to a start-up control method for commercial vehicles equipped with AMT (Automated Manual Transmission), specifically to an adaptive start-up control method for commercial vehicles equipped with AMT on icy and snowy roads. Background Technology

[0002] AMT (Automated Manual Transmission) is widely used in commercial vehicles and some passenger cars due to its simple structure, low cost, and high transmission efficiency. However, vehicles equipped with AMT face serious challenges during start-up, especially on low-friction surfaces such as ice and snow: First, traditional start-up control strategies typically rely on throttle opening and engine speed to control clutch engagement, which can easily lead to excessive torque on icy or snowy surfaces, causing severe slippage, vehicle instability, or even inability to start. Second, excessively limiting the clutch engagement speed or engine torque to prevent slippage can easily result in weak start-up, overheating of the clutch friction plates, or engine stalling, leading to a jerky and uneven start-up process. Third, most existing strategies are based on fixed calibrations and cannot sense changes in road surface adhesion conditions in real time and dynamically adjust control parameters, resulting in unstable performance under different ice and snow conditions (such as compacted snow, ice, and mixed ice and snow).

[0003] To improve vehicle starting performance on rough roads, Chinese patent CN119821397A discloses a control method to enhance vehicle driving capability on icy or unpaved roads. This method identifies road surface information and activates the control mode when the wheels are not slipping. It calculates a feedforward base torque based on vehicle mass, road slope, and road type, and combines this with feedback adjustment to obtain a comprehensive torque, thereby controlling the vehicle to start stably. However, this scheme mainly relies on feedforward calculation and simple feedback adjustment, failing to fully utilize the key state information of drive wheel slip rate for precise closed-loop control. Furthermore, its control variables are mainly focused on torque adjustment, lacking coordinated control of clutch engagement speed, making it difficult to achieve an optimal balance between anti-slip and smoothness. In addition, this scheme lacks online learning and adaptive updating capabilities for the road adhesion coefficient, and its adaptability to different icy and snowy conditions needs improvement. Summary of the Invention

[0004] The purpose of this invention is to solve the technical problems of existing vehicles equipped with AMT having a fixed start-up control strategy on icy and snowy roads, which cannot adapt to different adhesion conditions, resulting in easy slippage, unevenness and poor adaptability. The invention provides an adaptive start-up control method for commercial vehicles equipped with AMT on icy and snowy roads.

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

[0006] An adaptive start control method for a commercial vehicle equipped with an AMT (Automated Manual Transmission) on icy and snowy roads, the commercial vehicle including an accelerator pedal, drive wheels, non-drive wheels, a CAN bus, and a longitudinal acceleration sensor, multiple wheel speed sensors, an adaptive controller, an EMS (Electronic Power Supply), and the AMT connected to the CAN bus; the EMS is connected to the engine, and the AMT is connected to the clutch; the multiple wheel speed sensors are respectively located on the drive wheels and non-drive wheels; the method is characterized by including the following steps:

[0007] S1. Construct a starting control mapping table for commercial vehicles on normal dry roads and a fuzzy rule base for adaptive compensation on icy and snowy roads, and store them in the adaptive controller; the starting control mapping table includes the mapping relationship between starting data and basic starting control parameters; the fuzzy rule base includes the mapping relationship between correction indicators and correction parameters.

[0008] S2. A start request is sent through the accelerator pedal. The adaptive controller receives the start request and obtains the start data. Based on this, it calls the start control mapping table to obtain the basic start control parameters.

[0009] S3. The adaptive controller acquires real-time signals from the longitudinal acceleration sensor and wheel speed sensor via the CAN bus. Simultaneously, the adaptive controller controls the clutch engagement speed, engine speed, and output torque according to the basic start control parameters. After the clutch begins to engage, it determines whether there is a slippage trend based on the real-time signal from the wheel speed sensor. If yes, proceed to step S4; otherwise, proceed to step S5.

[0010] S4. The adaptive controller estimates or retrieves the peak adhesion coefficient μ updated since the last start based on the slippage trend. max The peak adhesion coefficient μ was obtained. max Based on this, the target slip ratio λ of the drive wheel is estimated. target Then, using the real-time signal from the wheel speed sensor, the actual slip ratio λ of the drive wheel is calculated. act Based on this, the real-time correction index is obtained, and the fuzzy rule base is queried to output the real-time correction parameters; then the real-time correction parameters are used to correct the basic start control parameters in real time to obtain the real-time execution value of the basic start control parameters; the real-time execution value is sent to AMT and EMS respectively to control the clutch engagement speed, engine speed and output torque in real time until the vehicle starts smoothly, and then step S6 is executed.

[0011] S5. Send the basic start control parameters to AMT and EMS respectively to control the clutch engagement speed, engine speed and output torque until the vehicle starts smoothly, then execute step S6.

[0012] S6. After the vehicle starts smoothly, update the peak adhesion coefficient μ max and store it in the adaptive controller, thus completing the adaptive starting control of the commercial vehicle equipped with AMT on the ice and snow road surface.

[0013] Further, in step S1, the starting data includes the throttle opening and the vehicle load information;

[0014] The basic starting control parameters include the reference value of the clutch engagement speed, the reference value of the engine speed, and the reference value of the output torque;

[0015] The correction indexes include the magnitude and sign of the slip ratio deviation eλ and the slip rate change rate T;

[0016] The correction parameters include the clutch engagement speed correction amount ΔVc and the engine output torque correction amount ΔTe;

[0017] The adaptive controller is a fuzzy PID controller, a sliding mode variable structure controller, or a model predictive controller.

[0018] Further, in step S1, the specific method for constructing a fuzzy rule base for adaptive compensation on the ice and snow road surface is:

[0019] Divide the slip ratio deviation eλ into seven fuzzy subsets, namely: eλ≤a, a<eλ≤b, b<eλ≤c, c<eλ<e, e≤eλ<f, f≤eλ<g, eλ≥g; where a < b < c < 0 < e < f < g, and the unit is %;

[0020] Divide the slip rate change rate T into seven fuzzy subsets, namely T≤A, A <T≤B, B <T≤C, C<T<E, E≤T<F, F≤T<G, T≥G; where A < B < C < 0 < E < F < G, and the unit is % / s;

[0021] Divide the clutch engagement speed correction amount ΔVc into seven output levels, namely: h, i, j, 0, k, m, n; where h < i < j < 0 < k < m < n, and the unit is mm / s;

[0022] Divide the engine output torque correction amount ΔTe into seven output levels, namely H, I, J, 0, K, M, N; where H < I < J < 0 < K < M < N, and the unit is Nm;

[0023] According to the seven fuzzy subsets of the slip ratio deviation eλ and the slip rate change rate T, and the seven output levels of the clutch engagement speed correction amount ΔVc and the engine output torque correction amount ΔTe, construct a fuzzy rule base for adaptive compensation on the ice and snow road surface;

[0024] The fuzzy rule base is:

[0025] If eλ ≥ g and T ≥ G, then ΔVc = h, ΔTe = H, causing the clutch to disengage quickly, rapidly reducing the engine's output torque and adaptively adjusting the rotational speed;

[0026] If eλ ≥ g and A < T ≤ B, then ΔVc = i, ΔTe = I, causing the clutch to disengage slowly, appropriately reducing the engine's output torque and adaptively adjusting the rotational speed;

[0027] If e ≤ eλ < f and E ≤ T < F, then ΔVc = j, ΔTe = J, causing the clutch to disengage slightly, slightly reducing the engine's output torque and adaptively adjusting the rotational speed;

[0028] If c < eλ < e and C < T < E, then ΔVc = 0, ΔTe = 0, causing the clutch to maintain the current engaged state, and the engine to maintain the current output torque and rotational speed;

[0029] If b < eλ ≤ c and B < T ≤ C, then ΔVc = k, ΔTe = K, causing the clutch to engage slightly faster, slightly increasing the engine's output torque and adaptively adjusting the rotational speed.

[0030] Further, step S2 is specifically as follows:

[0031] A start request is sent through the accelerator pedal. The adaptive controller receives the start request through the CAN bus and obtains the accelerator opening of the accelerator pedal and the vehicle load information; according to the accelerator opening and the vehicle load information, the start control mapping table is called to obtain the clutch engagement speed reference value, the engine rotational speed reference value, and the output torque reference value;

[0032] Step S5 is specifically as follows:

[0033] The clutch engagement speed reference value, the engine rotational speed reference value, and the output torque reference value are respectively used as the clutch engagement speed execution value, the engine rotational speed execution value, and the output torque execution value; then, the engagement speed execution value is sent to the AMT to control the clutch engagement speed, and the rotational speed execution value and the output torque execution value are sent to the EMS to control the engine rotational speed and output torque until the vehicle starts smoothly, and then step S6 is executed.

[0034] Further, step S3 is specifically as follows:

[0035] S3.1. The adaptive controller obtains the real-time signals of the longitudinal acceleration sensor and the wheel speed sensor through the CAN bus; at the same time, the adaptive controller controls the clutch engagement speed, the engine rotational speed, and the output torque respectively according to the clutch engagement speed reference value, the engine rotational speed reference value, and the output torque reference value;

[0036] S3.2 After the clutch begins to engage, determine whether there is a slippage trend by using the real-time signal from the wheel speed sensor; if yes, proceed to step S4; otherwise, proceed to step S5.

[0037] Furthermore, step S3.2 specifically includes:

[0038] S3.2.1 After the clutch begins to engage, the wheel speeds of each drive wheel and its corresponding non-drive wheel are obtained through the real-time signal from the wheel speed sensor.

[0039] S3.2.2 Calculate the wheel speed difference between each drive wheel and its corresponding non-drive wheel to determine whether there is a slippage trend;

[0040] If the difference between the speed of any driving wheel and its corresponding non-driving wheel is not zero, it is determined that there is a slippage tendency, and then step S4 is executed;

[0041] If the difference between the speeds of all drive wheels and their corresponding non-drive wheels is zero, it is determined that there is no slippage tendency, and then step S5 is executed.

[0042] Furthermore, step S4 specifically includes:

[0043] S4.1 Determine whether this is the first start on an icy or snowy road surface using the adaptive controller; if yes, proceed to step S4.2; if no, proceed to step S4.3.

[0044] S4.2 The adaptive controller estimates the peak adhesion coefficient μ based on the slippage trend. max Then proceed to step S4.4;

[0045] S4.3 Retrieve the peak adhesion coefficient μ updated since the last start-up, stored in the adaptive controller. max As the peak adhesion coefficient μ max Then proceed to step S4.4;

[0046] S4.4, Based on the peak adhesion coefficient μ max Estimate the target slip ratio λ of the drive wheel target ;

[0047] S4.5 Adaptive Start-up Control Based on Slip Rate Feedback

[0048] S4.5.1 The adaptive controller uses real-time signals from wheel speed sensors to calculate the actual slip ratio λ of the drive wheels based on the average wheel speed of the non-drive wheels and the wheel speed of the drive wheels. act ;

[0049] S4.5.2, The adaptive controller adjusts the actual slip ratio λ. act With the target slip ratio λ targetCalculate the slip ratio deviation eλ and the slip ratio change rate T;

[0050] S4.5.3. Based on the magnitude and sign of the slip ratio deviation eλ and the slip ratio change rate T, query the fuzzy rule base and output the clutch engagement speed correction amount ΔVc and the engine output torque correction amount ΔTe in real time.

[0051] S4.5.4. The clutch engagement speed reference value is corrected using the clutch engagement speed correction amount ΔVc to obtain the real-time execution value of the clutch engagement speed; at the same time, the engine output torque reference value is corrected using the engine output torque correction amount ΔTe, and the engine speed reference value is adaptively adjusted to obtain the real-time execution value of the engine output torque and the real-time execution value of the engine speed.

[0052] S4.5.5. Send the real-time engagement speed value to the AMT to control the clutch engagement speed, and send the real-time speed value and real-time output torque value to the EMS to control the engine speed and output torque.

[0053] S4.5.6. Repeat steps S4.5.1 to S4.5.5 until the vehicle starts smoothly, then execute step S6.

[0054] Further, in step S4.5.2, the calculation formulas for the slip ratio deviation eλ and the slip ratio change rate T are as follows:

[0055] ;

[0056] ;

[0057] In the formula, The actual slip ratio at the current time t. The actual slip ratio at the previous moment. This is the time interval between the current moment and the previous moment, expressed in seconds.

[0058] Further, in step S6, the peak adhesion coefficient μ is updated. max The method is as follows:

[0059] By analyzing the actual slip ratio λ of the drive wheel act The relationship between the longitudinal acceleration obtained from the longitudinal acceleration sensor and the current road surface adhesion capability is used to infer the current road surface adhesion coefficient μ. max ;

[0060] Alternatively, when the actual slip ratio is stably controlled at the target slip ratio λ targetWhen the distance is near, the adaptive controller records the average value of the clutch-transmitted torque at that moment, and calculates the peak adhesion coefficient μ of the current road surface by combining the known transmission parameters and drive shaft load. max .

[0061] Furthermore, step S1 also includes setting a preset actual slip ratio λ. act The danger threshold is determined and stored in the adaptive controller;

[0062] Following step S4.5.1, safety protection steps are also included:

[0063] If the actual slip ratio λ act If the dangerous threshold is exceeded and continues for a certain period of time, the adaptive controller immediately sends a command to the AMT to quickly disengage the clutch to a position below the semi-engagement point, and sends a command to the EMS to significantly reduce engine torque to interrupt the start-up and wait for the start-up request to be issued again through the accelerator pedal.

[0064] Compared with the prior art, the present invention has the following beneficial technical effects:

[0065] 1. This invention discloses an adaptive start control method for commercial vehicles equipped with AMT (Automated Manual Transmission) on icy and snowy roads. Through real-time slip ratio feedback control, it actively suppresses the slip ratio of the drive wheels within the optimal target range, fundamentally avoiding the risk of severe wheel spin and vehicle instability during start-up on icy and snowy roads. By adaptively adjusting the clutch engagement speed in conjunction with the engine speed and output torque, it avoids vehicle vibration or impact caused by abrupt torque control, improving driving comfort. By controlling the slip ratio near the peak of the adhesion coefficient, it maximizes the use of limited ground adhesion, achieving the fastest possible start-up on low-traction surfaces and shortening start-up time. Simultaneously, it updates the peak adhesion coefficient μ after start-up. max This method adapts to varying icy and snowy road conditions (dry snow, wet ice, etc.) and changes in adhesion conditions on the same road segment, improving the stability and adaptability of the control system. It primarily relies on existing vehicle sensors (wheel speed, throttle, acceleration, etc.), requiring no additional hardware and can be implemented through software algorithm upgrades, making it easy to promote and apply on existing AMT vehicle platforms. It fundamentally solves the problem of slippage and loss of control caused by excessive torque on the drive wheels when starting in commercial vehicles equipped with AMT on icy and snowy roads, while avoiding weak starting or engine stalling due to excessive torque limiting. It achieves synergistic optimization of safety and smoothness and possesses adaptive capabilities under different icy and snowy conditions.

[0066] 2. This invention provides an adaptive start-up control method for commercial vehicles equipped with AMT (Automated Manual Transmission) on icy and snowy roads. By using throttle opening and vehicle load information as start-up data, the basic control parameters are made more closely aligned with actual operating conditions. Using slip ratio deviation and slip ratio change rate as correction indicators, the method accurately reflects the slippage state and its changing trend of the drive wheels, providing a reliable decision-making basis for subsequent precise control. Simultaneously, a quantitative mapping relationship between slip ratio deviation and its changing rate and correction parameters is constructed through the specific rules of a fuzzy rule base. By setting control rules for different operating conditions (such as rapidly disengaging the clutch and reducing torque when slippage increases sharply, and slowly adjusting when slippage is slight), the controller can adopt differentiated control strategies according to the severity and changing trend of slippage. This ensures timely slippage suppression while avoiding drastic fluctuations in control actions, significantly improving the smoothness and stability of the start-up process.

[0067] 3. This invention provides an adaptive start-up control method for commercial vehicles equipped with AMT on icy and snowy roads, clarifying the acquisition method of basic start-up control parameters and the control path when there is no slippage trend. By using throttle opening and vehicle load information as the basis for calling the start-up control mapping table, the rationality of the basic control parameters is ensured; at the same time, when there is no slippage trend, the reference value is directly used to complete the start-up, simplifying the control process, reducing the system's computational burden, and demonstrating the flexibility and practicality of the control method.

[0068] 4. This invention provides an adaptive start control method for commercial vehicles equipped with AMT (Automated Manual Transmission) on icy and snowy roads. By acquiring sensor signals and comparing wheel speeds at the moment of clutch engagement, it achieves early identification of slippage trends, gaining valuable time for subsequent control mode switching. This embodies the "prevention-oriented" control philosophy and effectively avoids the deterioration of slippage. Specifically, it determines the presence of slippage trends by calculating the wheel speed difference between the drive wheels and non-drive wheels. This method is based on existing wheel speed sensor signals, requires no additional hardware, and is simple and reliable in calculation. By comparing all drive wheels one by one, it can accurately identify the slippage trends of individual or multiple drive wheels, providing a precise basis for control decisions.

[0069] 5. This invention provides an adaptive start control method for commercial vehicles equipped with AMT (Automated Manual Transmission) on icy and snowy roads. Through branching processing for first-time and subsequent starts, it achieves reasonable initialization of the peak adhesion coefficient. By employing cyclical control involving target slip ratio setting, real-time calculation of actual slip ratio, fuzzy rule query, and parameter correction, a complete closed-loop control circuit is constructed, ensuring optimal control throughout the clutch engagement process until the vehicle starts smoothly. Simultaneously, by defining the calculation formulas for slip ratio deviation eλ and slip ratio change rate T, the quantification and calculation methods of key control indicators are clarified. Dividing the difference between the actual slip ratio at the current moment and the previous moment by the time interval accurately reflects the rate of change of slip ratio, providing richer decision-making information for the fuzzy controller and making the control response more predictable and accurate.

[0070] 6. This invention provides an adaptive start control method for commercial vehicles equipped with AMT (Automated Manual Transmission) on icy and snowy roads. By analyzing the relationship between the actual slip ratio and longitudinal acceleration, or observing the torque demand under a specific slip ratio, the system can accurately deduce the current road surface's adhesion capability. This online learning mechanism allows the system to continuously accumulate road surface information and optimize the target slip ratio setting for subsequent starts. With increased usage, the control performance continuously improves.

[0071] 7. This invention provides an adaptive start-up control method for commercial vehicles equipped with AMT on icy and snowy roads. By setting a dangerous threshold for the actual slip rate and an over-limit protection mechanism, a dual safety guarantee is constructed. When extreme slippage occurs, the system can forcibly interrupt the start-up process, effectively preventing the risk of vehicle loss of control due to control system failure or extreme road conditions. This significantly improves the system's fault tolerance and safety, providing reliable safety for drivers and passengers. Attached Figure Description

[0072] Figure 1 This is a flowchart illustrating an embodiment of the adaptive start-up control method for commercial vehicles equipped with AMT on icy and snowy roads according to the present invention. Detailed Implementation

[0073] To make the objectives, advantages, and features of the present invention clearer, the following detailed description of an adaptive start control method for commercial vehicles equipped with AMT on icy and snowy roads, in conjunction with the accompanying drawings and specific embodiments, is provided below. Those skilled in the art should understand that these embodiments are merely illustrative of the technical principles of the present invention and are not intended to limit the scope of protection of the present invention.

[0074] An adaptive starting control method for a commercial vehicle equipped with AMT on ice and snow roads, which is used for the adaptive starting of a commercial vehicle equipped with AMT on ice and snow roads. The commercial vehicle includes an accelerator pedal, drive wheels, non-drive wheels, a CAN bus, and a longitudinal acceleration sensor, multiple wheel speed sensors, an adaptive controller, an EMS (i.e., engine management system), and an AMT connected to the CAN bus; the EMS is connected to an engine and an accelerator pedal, and the AMT is connected to a clutch; the multiple wheel speed sensors are respectively arranged at corresponding positions of the drive wheels and non-drive wheels; as Figure 1 shown, it includes the following specific steps:

[0075] S1. Construct a starting control mapping table for the commercial vehicle on normal dry roads and a fuzzy rule base for adaptive compensation on ice and snow roads, and store them in the adaptive controller; the starting control mapping table includes the mapping relationship between starting data and basic starting control parameters; the fuzzy rule base includes the mapping relationship between correction indicators and correction parameters. Preset a dangerous threshold of the actual slip ratio λact and store it in the adaptive controller.

[0076] Among them, the starting data includes the throttle opening and vehicle load information; the basic starting control parameters include the reference value of the clutch engagement speed, the reference value of the engine speed, and the reference value of the output torque; the correction indicators include the magnitude and sign of the slip ratio deviation eλ and the slip ratio change rate T; the correction parameters include the clutch engagement speed correction amount ΔVc and the engine output torque correction amount ΔTe. The adaptive controller is a fuzzy PID controller, a sliding mode variable structure controller, or a model predictive controller. In this embodiment, the fuzzy PID controller is used as the adaptive controller.

[0077] The specific method for constructing a fuzzy rule base for adaptive compensation on ice and snow roads is:

[0078] Divide the slip ratio deviation eλ into seven fuzzy subsets, namely: NB1 (i.e., negative large), NM1 (i.e., negative medium), NS1 (i.e., negative small), ZO1 (i.e., close to zero), PS1 (i.e., positive small), PM1 (i.e., positive medium), PB1 (i.e., positive large); where, NB1 corresponds to eλ ≤ a; NM1 corresponds to a < eλ ≤ b; NS1 corresponds to b < eλ ≤ c; ZO1 corresponds to c < eλ < e; PS1 corresponds to e ≤ eλ < f; PM1 corresponds to f ≤ eλ < g; PB1 corresponds to eλ ≥ g; in the formula, a < b < c < 0 < e < f < g, and the unit is %. In this embodiment, a = -5, b = -2, c = -0.5, e = 0.5, f = 2, g = 5.

[0079] The slip ratio change rate T is divided into seven fuzzy subsets, namely: NB2 (i.e., negative large), NM2 (i.e., negative medium), NS2 (i.e., negative small), ZO2 (i.e., close to zero), PS2 (i.e., positive small), PM2 (i.e., positive medium), PB2 (i.e., positive large); where NB2 corresponds to T ≤ A; NM2 corresponds to A < T ≤ B; NS2 corresponds to B < T ≤ C; ZO2 corresponds to C < T < E; PS2 corresponds to E ≤ T < F; PM2 corresponds to F ≤ T < G; PB2 corresponds to T ≥ G; where A < B < C < 0 < E < F < G, and the unit is % / s. In this embodiment, A = -8, B = -3, C = -1, E = 1, F = 3, G = 8.

[0080] The clutch engagement speed correction amount ΔVc is divided into seven output levels, namely: NB3 (i.e., negative large), NM3 (i.e., negative medium), NS3 (i.e., negative small), ZO3 (i.e., zero), PS3 (i.e., positive small), PM3 (i.e., positive medium), PB3 (i.e., positive large); where NB3 corresponds to h, NM3 corresponds to i, NS3 corresponds to j, ZO3 corresponds to 0, PS3 corresponds to k, PM3 corresponds to m, PB3 corresponds to n; where h < i < j < 0 < k < m < n, and the unit is mm / s. In this embodiment, h = -4, i = -2, j = -1, k = 1, m = 2, n = 3.

[0081] The engine output torque correction amount ΔTe is divided into seven output levels, namely: NB4 (i.e., negative large), NM4 (i.e., negative medium), NS4 (i.e., negative small), ZO4 (i.e., zero), PS4 (i.e., positive small), PM4 (i.e., positive medium), PB4 (i.e., positive large); where NB4 corresponds to H, NM4 corresponds to I, NS4 corresponds to J, ZO4 corresponds to 0, PS4 corresponds to K, PM4 corresponds to M, PB4 corresponds to N; where H < I < J < 0 < K < M < N, and the unit is Nm. In this embodiment, H = -120, I = -60, J = -30, K = 30, M = 60, N = 100.

[0082] According to the seven fuzzy subsets of the slip ratio deviation eλ and the slip ratio change rate T, and the seven output levels of the clutch engagement speed correction amount ΔVc and the engine output torque correction amount ΔTe, a fuzzy rule base for adaptive compensation on ice and snow roads is constructed;

[0083] The fuzzy rule base is:

[0084] If \(e\lambda\geq g\) and \(T\geq G\), then \(\Delta V_c = h\), \(\Delta T_e = H\), which makes the clutch disengage quickly, rapidly reduces the output torque of the engine and adaptively adjusts the speed; if \(e\lambda\geq g\) and \(A < T\leq B\), then \(\Delta V_c = i\), \(\Delta T_e = I\), which makes the clutch disengage slowly, appropriately reduces the output torque of the engine and adaptively adjusts the speed; if \(e\leq e\lambda< f\) and \(E\leq T< F\), then \(\Delta V_c = j\), \(\Delta T_e = J\), which makes the clutch disengage slightly, slightly reduces the output torque of the engine and adaptively adjusts the speed; if \(c< e\lambda< e\) and \(C< T< E\), then \(\Delta V_c = 0\), \(\Delta T_e = 0\), which keeps the clutch in the current engaged state and the engine maintains the current output torque and speed; if \(b< e\lambda\leq c\) and \(B < T\leq C\), then \(\Delta V_c = k\), \(\Delta T_e = K\), which makes the clutch engage slightly faster, slightly increases the output torque of the engine and adaptively adjusts the speed. Among them, an example of the fuzzy rule base is shown in Table 1.

[0085] Table 1 Example of Fuzzy Rule Base

[0086]

[0087] S2. Send a start request through the accelerator pedal. The adaptive controller receives the start request, obtains the start data, and accordingly calls the start control mapping table to obtain the basic start control parameters.

[0088] Specifically: Send a start request through the accelerator pedal. The adaptive controller receives the start request through the CAN bus and obtains the throttle opening of the accelerator pedal and the vehicle load information; call the start control mapping table according to the throttle opening and vehicle load information to obtain the reference value of the clutch engagement speed, the reference value of the engine speed, and the reference value of the output torque.

[0089] S3. The adaptive controller obtains the real-time signals of the longitudinal acceleration sensor and the wheel speed sensor through the CAN bus; at the same time, the adaptive controller controls the clutch engagement speed, the engine speed, and the output torque respectively according to the basic start control parameters; after the clutch starts to engage (generally at the moment when the clutch starts to engage, at this time the output torque of the engine is very small), judge whether there is a slipping trend through the real-time signal of the wheel speed sensor; if so, execute step S4; if not, execute step S5.

[0090] Specifically:

[0091] S3.1. The adaptive controller obtains the real-time signals of the longitudinal acceleration sensor and the wheel speed sensor through the CAN bus; at the same time, the adaptive controller controls the clutch engagement speed, the engine speed, and the output torque respectively according to the reference value of the clutch engagement speed, the reference value of the engine speed, and the reference value of the output torque.

[0092] S3.2 After the clutch begins to engage, determine whether there is a slippage trend by using the real-time signal from the wheel speed sensor; if yes, proceed to step S4; otherwise, proceed to step S5.

[0093] S3.2.1 After the clutch begins to engage, the wheel speeds of each drive wheel and its corresponding non-drive wheel are obtained through the real-time signal from the wheel speed sensor.

[0094] S3.2.2 Calculate the wheel speed difference between each drive wheel and its corresponding non-drive wheel to determine whether there is a slippage trend.

[0095] If the difference between the speed of any driving wheel and its corresponding non-driving wheel is not zero, it is determined that there is a slippage tendency, and then step S4 is executed.

[0096] If the difference between the speeds of all drive wheels and their corresponding non-drive wheels is zero, it is determined that there is no slippage tendency, and then step S5 is executed.

[0097] S4. The adaptive controller estimates or retrieves the peak adhesion coefficient μ updated since the last start based on the slippage trend. max The peak adhesion coefficient μ was obtained. max Based on this, the target slip ratio λ of the drive wheel is estimated. target Then, using the real-time signal from the wheel speed sensor, the actual slip ratio λ of the drive wheel is calculated. act Based on this, the real-time correction index is obtained, and the fuzzy rule base is queried to output the real-time correction parameters. The real-time correction parameters are then used to correct the basic start control parameters in real time to obtain the real-time execution value of the basic start control parameters. The real-time execution value is sent to AMT and EMS respectively to control the clutch engagement speed, engine speed and output torque in real time until the vehicle starts smoothly, and then step S6 is executed.

[0098] Specifically:

[0099] S4.1 Determine whether this is the first start on an icy or snowy road surface using the adaptive controller; if yes, proceed to step S4.2; if no, proceed to step S4.3.

[0100] S4.2 The adaptive controller estimates the peak adhesion coefficient μ based on the slippage trend. max (This value is usually located near the peak point of the slip rate-adhesion coefficient curve for low-adhesion surfaces. For example, based on the magnitude of the initial slip, refer to the typical range of adhesion coefficient for icy and snowy surfaces (0.1~0.3) and obtain a preliminary estimate through linear interpolation or table lookup.) Then proceed to step S4.4.

[0101] S4.3 Retrieve the peak adhesion coefficient μ updated since the last start-up, stored in the adaptive controller. max As the peak adhesion coefficient μmax Then proceed to step S4.4.

[0102] S4.4, Based on the peak adhesion coefficient μ max Estimate the target slip ratio λ of the drive wheel target .

[0103] S4.5 Adaptive Start-up Control Based on Slip Rate Feedback

[0104] S4.5.1 The adaptive controller uses real-time signals from wheel speed sensors to calculate the actual slip ratio λ of the drive wheels in real time, based on the average wheel speed of the non-drive wheels (i.e., the vehicle speed of the commercial vehicle) and the wheel speed of the drive wheels. act .

[0105] S4.5.2, The adaptive controller adjusts the actual slip ratio λ. act With the target slip ratio λ target Calculate the slip ratio deviation eλ and the slip ratio change rate T.

[0106] The formulas for calculating the slip ratio deviation eλ and the slip ratio change rate T are as follows:

[0107] ;

[0108] ;

[0109] In the formula, The actual slip ratio at the current time t. The actual slip ratio at the previous moment. This is the time interval between the current moment and the previous moment, expressed in seconds.

[0110] S4.5.3. Based on the magnitude and sign of the slip ratio deviation eλ and the slip ratio change rate T, query the fuzzy rule base and output the clutch engagement speed correction ΔVc and the engine output torque correction ΔTe in real time.

[0111] S4.5.4. The clutch engagement speed reference value is corrected using the clutch engagement speed correction amount ΔVc to obtain the real-time execution value of the clutch engagement speed; at the same time, the engine output torque reference value is corrected using the engine output torque correction amount ΔTe, and the engine speed reference value is adaptively adjusted to obtain the real-time execution value of the engine output torque and the real-time execution value of the engine speed.

[0112] S4.5.5 The real-time engagement speed value is sent to the AMT to control the clutch engagement speed, and the real-time speed and output torque values ​​are sent to the EMS to control the engine speed and output torque.

[0113] S4.5.6. Repeat steps S4.5.1 to S4.5.5 until the vehicle starts smoothly, then execute step S6.

[0114] Following step S4.5.1, safety protection steps are also included:

[0115] If the actual slip ratio λ act If the dangerous threshold is exceeded and continues for a certain period of time, the adaptive controller immediately sends a command to the AMT to quickly disengage the clutch to a position below the semi-engaged point, and sends a command to the MES to significantly reduce engine torque to interrupt the start-up and wait for the start-up request to be issued again through the accelerator pedal.

[0116] S5. Send the basic start-up control parameters to the AMT and EMS respectively to control the clutch engagement speed, engine speed and output torque until the vehicle starts smoothly, then execute step S6.

[0117] Specifically, the clutch engagement speed reference value, engine speed reference value, and output torque reference value are respectively used as the clutch engagement speed execution value, engine speed execution value, and output torque execution value; then, the engagement speed execution value is sent to the AMT to control the clutch engagement speed, and the speed execution value and output torque execution value (the engine target speed execution value) are sent to the EMS to control the engine speed and output torque until the vehicle starts smoothly, and then step S6 is executed.

[0118] S6. After the vehicle starts smoothly, update the peak adhesion coefficient μ. max The data is stored in the adaptive controller, thereby enabling the commercial vehicle equipped with AMT to perform adaptive start control on icy and snowy roads.

[0119] Among them, the updated peak adhesion coefficient μ max The method is as follows:

[0120] By analyzing the actual slip ratio λ of the drive wheel act The relationship between the longitudinal acceleration obtained from the longitudinal acceleration sensor and the current road surface adhesion capability is used to infer the current road surface adhesion coefficient μ. max .

[0121] In other embodiments, the actual slip ratio can also be stably controlled at the target slip ratio λ. target When the distance is near, the adaptive controller records the average value of the clutch-transmitted torque at that moment, and calculates the peak adhesion coefficient μ of the current road surface by combining the known transmission parameters and drive shaft load. max ...

[0122] For example:

[0123] (1) The driver starts the commercial vehicle equipped with AMT, puts it in D gear, and lightly presses the accelerator pedal (accelerator opening is 20%). The adaptive controller recognizes the start request.

[0124] (2) The adaptive controller obtains the engine speed reference value of 1500 rpm, the output torque reference value of 200 N·m, and the clutch engagement speed reference value of 5 rpm / s from the basic mapping table based on the 20% throttle opening. (Characterized by the speed difference between the clutch master and slave plates).

[0125] (3) The adaptive controller reads the real-time signal from the wheel speed sensor, begins to engage the clutch, and finds that the difference between the wheel speed of one of the drive wheels and its corresponding non-drive wheel is not zero, indicating an initial slippage tendency. Since this is the first start on an icy or snowy road surface, the peak adhesion coefficient μ of the current road surface is initially estimated. max The value is 0.2, from which the target slip ratio λ is obtained. target =10%.

[0126] (4) When the clutch's driving and driven discs begin to engage and transmit torque, the drive wheel speed begins to increase. The adaptive controller calculates in real time: the vehicle speed (obtained from the non-drive wheel speed) is approximately 0.1 m / s, and the drive wheel speed corresponds to 0.12 m / s, then the actual slip ratio λ act = (0.12-0.1) / 0.12≈16.7%.

[0127] (5) Calculate the slip ratio deviation eλ = 16.7% - 10% = 6.7%. The slip ratio deviation eλ is positive and the slip ratio change rate T is also positive, indicating that slippage is increasing.

[0128] (6) Input the slip ratio deviation eλ and slip ratio change rate T into the adaptive controller (i.e., the fuzzy PID controller). The adaptive controller judges that there is a moderate slip trend and outputs the clutch engagement speed correction amount ΔVc=-3 rpm / s and the engine output torque correction amount ΔTe=-30 Nm (the engine output torque is reduced).

[0129] (7) The adaptive controller controls the clutch to engage at a new speed of 2 rpm / s, while the engine output torque decreases and the engine speed is adjusted adaptively. Soon, the actual slip ratio λ... act It fell back to 12% and then stabilized around 10%.

[0130] (8) Throughout the engagement process, the adaptive controller continuously transmits the actual slip ratio λ act And the peak adhesion coefficient μ actually utilized by estimating the vehicle's small acceleration. max After this initial phase, the peak adhesion system μ was updated. max This data is stored in the adaptive controller to learn the actual μ value of the road segment.max It is approximately 0.22.

[0131] (9) If the adaptive controller uses the updated μ again on the same road segment, it will be able to use the updated μ. max The target slip ratio λ is set to 0.22. target (Possibly adjusted to 11%), thus enabling a faster start.

[0132] Through the above closed-loop control, commercial vehicles equipped with AMT can achieve a smooth start on ice surfaces without significant slippage (the slip ratio always fluctuates around 10%).

[0133] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, and are not intended to limit them. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the present invention.

Claims

1. A method for adaptive start control of a commercial vehicle equipped with an AMT on icy and snowy roads, the commercial vehicle comprising an accelerator pedal, drive wheels, non-drive wheels, a CAN bus, and a longitudinal acceleration sensor, multiple wheel speed sensors, an adaptive controller, an EMS, and an AMT connected to the CAN bus; the EMS is connected to an engine, and the AMT is connected to a clutch; the multiple wheel speed sensors are respectively disposed on the drive wheels and the non-drive wheels; characterized in that, It includes the following steps: S1. Construct a starting control mapping table for a commercial vehicle on a normal dry road surface and a fuzzy rule base for adaptive compensation on an ice and snow road surface, and store them in an adaptive controller; the starting control mapping table includes the mapping relationship between starting data and basic starting control parameters; the fuzzy rule base includes the mapping relationship between correction indicators and correction parameters; S2. Send a starting request through the accelerator pedal. The adaptive controller receives the starting request and obtains the starting data, and accordingly calls the starting control mapping table to obtain the basic starting control parameters; S3. The adaptive controller obtains the real-time signals of the longitudinal acceleration sensor and the wheel speed sensor through the CAN bus; at the same time, the adaptive controller controls the engagement speed of the clutch, the engine speed and the output torque respectively according to the basic starting control parameters; after the clutch starts to engage, it judges whether there is a slipping tendency through the real-time signal of the wheel speed sensor; If so, execute step S4; if not, execute step S5; S4. The adaptive controller estimates or retrieves the peak adhesion coefficient μ updated since the last start based on the slippage trend. max The peak adhesion coefficient μ was obtained. max Based on this, the target slip ratio λ of the drive wheel is estimated. target Then, using the real-time signal from the wheel speed sensor, the actual slip ratio λ of the drive wheel is calculated. act Based on this, real-time correction indicators are obtained, and the fuzzy rule base is queried to output real-time correction parameters. Then, use the real-time correction parameter to perform real-time correction on the basic starting control parameter to obtain the real-time execution value of the basic starting control parameter; Send the real-time execution value to the AMT and EMS respectively to control the engagement speed of the clutch, the engine speed and the output torque in real time. After the vehicle starts smoothly, execute step S6; S5. Send the basic starting control parameter to the AMT and EMS respectively to control the engagement speed of the clutch, the engine speed and the output torque. After the vehicle starts smoothly, execute step S6; S6. After the vehicle starts smoothly, update the peak adhesion coefficient μ. max The data is stored in the adaptive controller, thereby enabling the commercial vehicle equipped with AMT to perform adaptive start control on icy and snowy roads.

2. The method for adaptive starting control of a commercial vehicle equipped with AMT on an ice and snow road surface according to claim 1, wherein: In step S1, the starting data includes the throttle opening and the vehicle load information; The basic starting control parameters include the reference value of the clutch engagement speed, the reference value of the engine speed and the reference value of the output torque; The correction indicators include the magnitude and positive / negative of the slip ratio deviation eλ and the slip ratio change rate T; The correction parameters include the clutch engagement speed correction amount ΔVc and the engine output torque correction amount ΔTe; The adaptive controller is a fuzzy PID controller, a sliding mode variable structure controller or a model predictive controller.

3. The adaptive start control method for commercial vehicles equipped with AMT on icy and snowy roads according to claim 2, characterized in that, In step S1, the specific method for constructing a fuzzy rule base for adaptive compensation on an ice and snow road surface is: Divide the slip ratio deviation eλ into seven fuzzy subsets, namely: eλ≤a, a<eλ≤b, b<eλ≤c, c<eλ<e, e≤eλ<f, f≤eλ<g, eλ≥g; where, a<b<c<0<e<f<g, unit is %; Divide the slip ratio change rate T into seven fuzzy subsets, namely: T≤A, A <T≤B, B <T≤C, C<T<E, E≤T<F, F≤T<G, T≥G; where, A<B<C<0<E<F<G, unit is % / s; Divide the clutch engagement speed correction amount ΔVc into seven output levels, namely: h, i, j, 0, k, m, n; where, h<i<j<0<k<m<n, unit is mm / s; The engine output torque correction ΔTe is divided into seven output levels, namely H, I, J, 0, K, M, and N; where H < I < J < 0 < K < M < N, and the unit is Nm; Based on the seven fuzzy subsets of the slip ratio deviation eλ and the slip rate change rate T, as well as the seven output levels of the clutch engagement speed correction ΔVc and the engine output torque correction ΔTe, a fuzzy rule base for adaptive compensation on ice and snow roads is constructed; The fuzzy rule base is as follows: If eλ ≥ g and T ≥ G, then ΔVc = h, ΔTe = H, to quickly disengage the clutch, rapidly reduce the engine output torque, and adaptively adjust the rotational speed; If eλ ≥ g and A < T ≤ B, then ΔVc = i, ΔTe = I, to slowly disengage the clutch, appropriately reduce the engine output torque, and adaptively adjust the rotational speed; If e ≤ eλ < f and E ≤ T < F, then ΔVc = j, ΔTe = J, to slightly disengage the clutch, slightly reduce the engine output torque, and adaptively adjust the rotational speed; If c < eλ < e and C < T < E, then ΔVc = 0, ΔTe = 0, to keep the clutch in the current engaged state, the engine in the current output torque and rotational speed; If b < eλ ≤ c and B < T ≤ C, then ΔVc = k, ΔTe = K, to engage the clutch slightly faster, slightly increase the engine output torque, and adaptively adjust the rotational speed.

4. The adaptive start-up control method for commercial vehicles equipped with AMT on icy and snowy roads according to claim 2 or 3, characterized in that, Step S2 is specifically as follows: A start request is sent through the accelerator pedal. The adaptive controller receives the start request through the CAN bus and obtains the accelerator opening of the accelerator pedal and the vehicle load information; according to the accelerator opening and the vehicle load information, the start control mapping table is called to obtain the clutch engagement speed reference value, the engine rotational speed reference value, and the output torque reference value; Step S5 is specifically as follows: The clutch engagement speed reference value, the engine rotational speed reference value, and the output torque reference value are respectively used as the clutch engagement speed execution value, the engine rotational speed execution value, and the output torque execution value; then, the engagement speed execution value is sent to the AMT to control the clutch engagement speed, and the rotational speed execution value and the output torque execution value are sent to the EMS to control the engine rotational speed and output torque until the vehicle starts smoothly, and then step S6 is executed.

5. The adaptive start control method for commercial vehicles equipped with AMT on icy and snowy roads according to claim 4, characterized in that, Step S3 is specifically as follows: S3.

1. The adaptive controller obtains the real-time signals of the longitudinal acceleration sensor and the wheel speed sensor through the CAN bus; at the same time, the adaptive controller controls the clutch engagement speed, the engine rotational speed, and the output torque according to the clutch engagement speed reference value, the engine rotational speed reference value, and the output torque reference value respectively; S3.

2. After the clutch starts to engage, it is judged whether there is a slipping tendency through the real-time signal of the wheel speed sensor; If so, step S4 is executed; if not, step S5 is executed.

6. The adaptive start control method for commercial vehicles equipped with AMT on icy and snowy roads according to claim 5, characterized in that, Step S3.2 is specifically as follows: S3.2.

1. After the clutch starts to engage, the wheel speeds of each driving wheel and its corresponding non-driving wheel are obtained through the real-time signal of the wheel speed sensor; S3.2.

2. Calculate the wheel speed difference between each driving wheel and its corresponding non-driving wheel to judge whether there is a slipping tendency; If the difference between the speed of any driving wheel and its corresponding non-driving wheel is not zero, it is determined that there is a slippage tendency, and then step S4 is executed; If the difference between the speeds of all drive wheels and their corresponding non-drive wheels is zero, it is determined that there is no slippage tendency, and then step S5 is executed.

7. The adaptive start control method for commercial vehicles equipped with AMT on icy and snowy roads according to claim 5, characterized in that, Step S4 is as follows: S4.1 Determine whether this is the first start on an icy or snowy road surface using the adaptive controller; if yes, proceed to step S4.2; if no, proceed to step S4.

3. S4.2 The adaptive controller estimates the peak adhesion coefficient μ based on the slippage trend. max Then proceed to step S4.4; S4.3 Retrieve the peak adhesion coefficient μ updated since the last start-up, stored in the adaptive controller. max As the peak adhesion coefficient μ max Then proceed to step S4.4; S4.4, Based on the peak adhesion coefficient μ max Estimate the target slip ratio λ of the drive wheel target ; S4.5 Adaptive Start-up Control Based on Slip Rate Feedback S4.5.1 The adaptive controller uses real-time signals from wheel speed sensors to calculate the actual slip ratio λ of the drive wheels based on the average wheel speed of the non-drive wheels and the wheel speed of the drive wheels. act ; S4.5.2, The adaptive controller adjusts the actual slip ratio λ. act With the target slip ratio λ target Calculate the slip ratio deviation eλ and the slip ratio change rate T; S4.5.

3. Based on the magnitude and sign of the slip ratio deviation eλ and the slip ratio change rate T, query the fuzzy rule base and output the clutch engagement speed correction amount ΔVc and the engine output torque correction amount ΔTe in real time. S4.5.

4. The clutch engagement speed reference value is corrected using the clutch engagement speed correction amount ΔVc to obtain the real-time execution value of the clutch engagement speed; at the same time, the engine output torque reference value is corrected using the engine output torque correction amount ΔTe, and the engine speed reference value is adaptively adjusted to obtain the real-time execution value of the engine output torque and the real-time execution value of the engine speed. S4.5.

5. Send the real-time engagement speed value to the AMT to control the clutch engagement speed, and send the real-time speed value and real-time output torque value to the EMS to control the engine speed and output torque. S4.5.

6. Repeat steps S4.5.1 to S4.5.5 until the vehicle starts smoothly, then execute step S6.

8. The adaptive start control method for commercial vehicles equipped with AMT on icy and snowy roads according to claim 7, characterized in that, In step S4.5.2, the calculation formulas for the slip ratio deviation eλ and the slip ratio change rate T are as follows: ； ； In the formula, The actual slip ratio at the current time t. The actual slip ratio at the previous moment. This is the time interval between the current moment and the previous moment, expressed in seconds.

9. The adaptive start control method for commercial vehicles equipped with AMT on icy and snowy roads according to claim 7, characterized in that, In step S6, the peak adhesion coefficient μ is updated. max The method is as follows: By analyzing the actual slip ratio λ of the drive wheel act The relationship between the longitudinal acceleration obtained from the longitudinal acceleration sensor and the current road surface adhesion capability is used to infer the current road surface adhesion coefficient μ. max ; Alternatively, when the actual slip ratio is stably controlled at the target slip ratio λ target When the distance is near, the adaptive controller records the average value of the clutch-transmitted torque at that moment, and calculates the peak adhesion coefficient μ of the current road surface by combining the known transmission parameters and drive shaft load. max .

10. The adaptive start-up control method for commercial vehicles equipped with AMT on icy and snowy roads according to claim 7, characterized in that: Step S1 also includes setting the actual slip ratio λ. act The danger threshold is determined and stored in the adaptive controller; Following step S4.5.1, safety protection steps are also included: If the actual slip ratio λ act If the dangerous threshold is exceeded and continues for a certain period of time, the adaptive controller immediately sends a command to the AMT to quickly disengage the clutch to a position below the semi-engagement point, and sends a command to the EMS to significantly reduce engine torque to interrupt the start-up and wait for the start-up request to be issued again through the accelerator pedal.

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