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CN-122014767-A - AMT clutch release rate smoothness optimization control method

CN122014767ACN 122014767 ACN122014767 ACN 122014767ACN-122014767-A

Abstract

The invention relates to the technical field of automatic speed change control of vehicles, and discloses a smoothness optimization control method for an AMT clutch release rate. The method comprises the steps of obtaining input signals such as the current rotating speed of an engine, the idling speed of the engine, the current torque of the engine, the feedback torque of a clutch, the rotating speed change rate of the engine, a ramp, a turning radius, the current gear, theoretical calculation starting gear, a braking signal, clutch target torque and the like, respectively calculating a first separation rate based on the ramp and the turning radius and a second separation rate based on the current torque of the engine and the feedback torque of the clutch, taking a smaller value of the two values as an initial output separation rate under a low-speed driving working condition, and determining a final separation rate by combining anti-dragging protection, anti-flameout protection, neutral working condition control and separation stroke end re-control, thereby improving the bump and anti-dragging impact of an AMT vehicle under a low-speed non-gear shifting working condition and improving driving smoothness and comfort.

Inventors

  • YAN ZHENGFENG
  • XU XIAN
  • ZHENG MINYI

Assignees

  • 合肥工业大学

Dates

Publication Date
20260512
Application Date
20260416

Claims (10)

  1. The smoothness optimization control method for the AMT clutch release rate is characterized by comprising the following steps: S1, acquiring input signals required by clutch release rate control, wherein the input signals at least comprise the current rotating speed of an engine, the idle speed of the engine, the current torque of the engine, the feedback torque of the clutch, the change rate of the rotating speed of the engine, a ramp, a turning radius, the current gear, a theoretical calculated starting gear, a braking signal and a clutch target torque; s2, determining a basic clutch release rate according to a ramp and a turning radius, correcting the basic clutch release rate based on an initial clutch feedback torque, and then sequentially combining anti-drag protection, anti-flameout protection and neutral gear working condition control to obtain a first release rate; s3, determining a second basic clutch release rate according to the current torque of the engine and the feedback torque of the clutch, and performing dynamic feedback correction based on the speed difference between the current speed of the engine and the idle speed of the engine and the speed change rate of the engine to obtain the second release rate; S4, judging whether the vehicle is in a low-speed driving condition according to the relation between the current gear and the theoretical calculation starting gear, taking the smaller value of the first separation rate and the second separation rate as an initial output separation rate when the vehicle is in the low-speed driving condition, and taking the first separation rate as the initial output separation rate when the vehicle is not in the low-speed driving condition; s5, determining the final separation rate of the clutch separation stroke end according to the change rate of the engine speed when the preset end control condition is met; And when the preset tail end control condition is not met, taking the initial output separation rate as a final separation rate.
  2. 2. The method for optimizing and controlling smoothness of AMT clutch release rate according to claim 1, wherein in step S1: The input signals comprise CAN bus signals, external sensor signals and TCU internal signals; The CAN bus signals comprise current rotation speed of an engine, idling speed of the engine, relative wheel speed of wheels, foot brake and hand brake signals; the external sensor signals include clutch feedback torque, ramp, and gear shift; The TCU internal signals include clutch target torque, engine speed rate of change, turning radius, current gear, and theoretical calculated starting gear.
  3. 3. The method for optimizing and controlling smoothness of AMT clutch release rate according to claim 1, wherein in step S2, the basic clutch release rate is corrected based on the initial clutch feedback torque, specifically: comparing the initial clutch feedback torque with a preset torque threshold; when the initial clutch feedback torque is larger than the preset torque threshold, correcting the basic clutch release rate by adopting a forward correction value, wherein the absolute value of the forward correction value is increased along with the increase of the initial clutch feedback torque; And when the initial clutch feedback torque is smaller than the preset torque threshold, correcting the basic clutch release rate by adopting a negative correction value, wherein the absolute value of the negative correction value increases as the initial clutch feedback torque decreases.
  4. 4. The method for optimizing control of smoothness of AMT clutch release rate according to claim 1, wherein said anti-drag protection in step S2 comprises: Triggering anti-reverse-dragging protection when the speed change rate of the engine is smaller than a first speed change rate threshold value, the speed difference between the current speed of the engine and the idle speed of the engine is smaller than a first speed difference threshold value, and the current torque of the engine is smaller than a first torque threshold value; after triggering the anti-reverse-dragging protection, comparing the corrected separation rate with the first protection separation rate, and taking the larger value of the corrected separation rate and the first protection separation rate as the separation rate after the anti-reverse-dragging protection.
  5. 5. The method for optimizing control of smoothness of AMT clutch release rate according to claim 4, wherein said flameout prevention and neutral condition control in step S2 comprises: When the speed difference between the current speed of the engine and the idle speed of the engine is smaller than a second speed difference threshold value, triggering flameout prevention protection, comparing the separation rate after the anti-dragging protection with a second protection separation rate, and taking the larger value of the two as the separation rate after the flameout prevention protection, wherein the second protection separation rate is larger than the first protection separation rate; And when the current gear is a neutral gear, comparing the separation rate after flameout prevention protection with the neutral gear separation rate, and taking the larger value of the separation rate and the neutral gear separation rate as the first separation rate.
  6. 6. The method for optimizing and controlling smoothness of AMT clutch release rate according to claim 1, wherein when determining the second basic clutch release rate according to the current torque of the engine and the clutch feedback torque in step S3, the following mapping relationship is satisfied: the greater the clutch feedback torque, the greater the second foundation clutch release rate; the smaller the current torque of the engine, the greater the second foundation clutch release rate; When the clutch feedback torque is less than the preset torque value, the second base clutch release rate remains a small value and no longer varies with the current torque of the engine.
  7. 7. The method for optimizing control of smoothness of AMT clutch release rate according to claim 1, wherein said dynamic feedback correction in step S3 comprises: presetting a first speed change rate threshold, a second speed change rate threshold and a third speed difference threshold, wherein the second speed change rate threshold is greater than the first speed change rate threshold; when the change rate of the engine rotating speed is larger than the first rotating speed change rate threshold value, the dynamic feedback correction is not carried out; When the speed difference between the current speed of the engine and the idle speed of the engine is larger than the third speed difference threshold value and the speed change rate of the engine is larger than the second speed change rate threshold value, the dynamic feedback correction is not carried out; And under the other conditions, carrying out dynamic feedback correction, wherein the dynamic feedback correction value increases along with the decrease of the rotating speed difference and increases along with the decrease of the rotating speed change rate of the engine.
  8. 8. The method for optimizing and controlling smoothness of AMT clutch release rate according to claim 1, wherein in step S4: The theoretical calculation starting gear is determined according to the quality of the ramp and the whole vehicle through a preset mapping relation; the gear difference between the current gear and the theoretical calculated starting gear is the gear serial number corresponding to the current gear minus the gear serial number corresponding to the theoretical calculated starting gear; and when the gear difference value is smaller than a preset gear shift threshold value or the current gear is a reverse gear, judging that the vehicle is in a low-speed driving working condition.
  9. 9. The method for optimizing and controlling smoothness of an AMT clutch release rate according to claim 1, wherein said predetermined end control conditions in step S5 comprise at least: the brake signal represents no hand brake and no foot brake of the vehicle; The current gear is equal to the theoretical calculated starting gear; The speed difference between the current speed of the engine and the idle speed of the engine is larger than a fourth speed difference threshold; the clutch target torque is less than a preset first clutch target torque threshold.
  10. 10. The method for optimizing and controlling smoothness of AMT clutch release rate according to claim 9, wherein when determining the final release rate at the end of clutch release stroke according to the rate of change of engine rotation speed in step S5, the following relationship is satisfied: The smaller the engine speed change rate, the greater the final separation rate; And the maximum value of the final separation rate is less than the initial output separation rate.

Description

AMT clutch release rate smoothness optimization control method Technical Field The invention relates to the technical field of automatic speed change control of vehicles, in particular to a clutch release rate smoothness optimization control method for an AMT (automatic mechanical transmission) under a low-speed non-gear-shifting working condition. Background The electric control mechanical automatic transmission has the characteristics of high transmission efficiency and high automatic control convenience of the manual transmission, and has been widely applied to the field of commercial vehicles. Along with the continuous improvement of the requirements of the whole vehicle on low-speed drivability, smoothness and comfort, the control quality of the AMT under non-gear shifting working conditions such as urban congestion road conditions, low-speed creeping, sliding with the vehicle, and throttle deceleration gradually becomes an important factor influencing user experience and the dynamic performance of the whole vehicle. Under the working conditions, the kinetic energy of the vehicle is low, the inertia of the system is relatively small, and the torsional elasticity and torque fluctuation of the transmission system are more easily transmitted to the whole vehicle layer. When the driver releases the accelerator pedal and intends to slide or decelerate, if the clutch is not properly controlled in a separation action, the phenomenon of irregularity easily occurs in the transition process from the combination to the disconnection of the power chain, and the problems of vehicle body pause, impact enhancement, abrupt deceleration or obvious reverse dragging of the engine are further presented. In the prior art, two kinds of ideas generally exist for clutch control under the working condition of low-speed driving. One type is a closed-loop control method based on clutch transmission torque, wherein the clutch is maintained in a certain half-engagement section by setting a torque upper limit value and a torque lower limit value, and then the clutch is controlled to be engaged or disengaged. Although the scheme can consider the torque transmission requirement in the low-speed driving process to a certain extent, the control core is more in maintaining the semi-combined state rather than carrying out fine calculation on the clutch release rate, so that when the scheme faces to multi-factor coupling scenes such as a ramp, steering, engine deceleration change, anti-dragging risk and the like, the release rate which is more adaptive to the current state is difficult to accurately output. Another type of scheme focuses on working condition identification and strategy switching, namely, identifying the situation of the current vehicle through information such as engine speed, torque, accelerator signals, brake signals, gear shifting requests and the like, and selecting a corresponding strategy from a plurality of preset separation strategies to execute. The scheme can cover various working conditions, but usually stays on a macroscopic control layer of a recognition working condition-selection strategy, and the scheme is still not deep enough in disclosure how to specifically adjust the clutch separation rate under specific working conditions along with the change of parameters such as gradient, turning radius, feedback torque, engine speed difference, engine speed change rate and the like. In addition, it is also common in existing engineering controls to perform the disengaging action at a pre-calibrated fixed clutch disengagement rate. The mode is simple to realize, but has limited adaptability to complex working conditions. Under the conditions of low gear, low vehicle speed and low inertia, the power chain is more sensitive to the clutch separation action due to larger transmission ratio and obvious torque amplification effect, if the separation speed is set too fast, the power chain is easily turned on and off violently to cause the impact and the jerk of the vehicle body, and if the separation speed is set too slow or the combination time is maintained too long, the reverse dragging torque of the engine can be transferred to the wheels more quickly to cause the rapid deceleration of the vehicle, and if the separation speed is set too fast, the engine speed can be reduced too fast and even the flameout can be generated seriously. Therefore, the prior art still lacks a control method capable of comprehensively considering external environment factors, power chain states, protection boundaries and separation end control requirements under the low-speed non-gear shifting working condition and outputting the refined clutch separation rate. Disclosure of Invention The invention aims to solve the technical problem of providing a smoothness optimization control method for the separation rate of an AMT clutch so as to solve the problems of the automatic transmission, the anti-dragging impact and the increase of flameout ri