Method for controlling synchronous impact of clutch

[0030] The present invention will be further described below in conjunction with the accompanying drawings. The present invention uses an electric automatic clutch. As attached figure 1 As shown, the electric automatic clutch system consists of servo motors, couplings, ball screws and other mechanisms, and is equipped with encoders, position sensors, and limit sensors. The invention uses the FreeScale MC9S12DT128 type 16-bit single-chip microcomputer to send pulse signals to control the movement of the servo motor. The rotation of the servo motor drives the ball screw to change the rotary motion into front and rear linear motion. Through the linear movement of the ball screw, the clutch release lever is pushed to realize the clutch separation and combination. The single-chip microcomputer also sends out a high level or low level while sending out pulses to control the rotation direction of the servo motor and realize the forward and backward movement of the ball screw. The amount of pulses sent by the encoder reflects the rotation angle of the servo motor. The position sensor is used to detect the displacement of the ball screw, and the limit sensor is used to define the starting point and ending point of the ball screw. The clutch separation process is as attached figure 2 As shown, the single chip microcomputer (PWM) module generates a square wave signal to control the movement of the servo motor. The square wave frequency determines the speed of the motor rotation. At the same time, the single chip generates a high level signal to control the positive rotation of the servo motor. The motor drives the ball screw to push the clutch release lever, the clutch friction plate is separated from the pressure plate, and the clutch position is detected by the position sensor. When the position reaches the end point of the ball screw, the limit sensor feedback signal to the single-chip microcomputer, the single-chip terminates the signal output, and the motor stops rotating , The ball screw then stops moving, realizing the separation operation of the clutch. The clutch engagement process is as attached image 3 As shown, the single-chip (PWM) module generates a square wave signal to control the movement of the servo motor. The square wave frequency determines the speed of the motor rotation. At the same time, the single-chip generates a low-level signal to control the servo motor to rotate in reverse. The motor drives the ball screw to retract in the reverse direction. The position sensor detects the clutch position. When the position reaches the starting point of the ball screw, the limit sensor feeds back a signal to the single-chip microcomputer. The single-chip terminates the signal output, the motor stops rotating, and the ball screw stops moving. Realize the engagement operation of the clutch.

[0031] The clutch is divided into three stages during the engagement phase. The first stage is the idle stroke stage. In this stage, the clutch output shaft speed is 0, and the clutch needs to be engaged quickly to reduce the power interruption time. Therefore, the method of "clutch fast engagement until the clutch output shaft speed changes suddenly" is adopted. The second stage is the sliding grinding stage. At this time, the clutch is in the friction sliding stage. The clutch needs to be engaged at a faster speed to shorten the sliding grinding time and reduce the sliding work. When the sliding grinding speed and sliding grinding are When the speed change rate reaches the set critical point, control the clutch to reverse movement at a fixed speed for separation operation. When the distance of the clutch reverse movement exceeds 2mm, continue to control the clutch to continue forward movement at the same speed in the slip phase Engage, that is, enter the third synchronization phase. To achieve the purpose of reducing the engagement pressure before synchronization, thereby reducing the friction torque before synchronization to reduce the synchronization shock, so as to realize the rapid and smooth synchronization of the clutch.

[0032] As attached Figure 4 As shown, the control process of the present invention is as follows:

[0033] Step 1. Determine whether the clutch is in the idle stroke stage according to whether the clutch output shaft has a rotational speed. When the clutch starts to engage, output a pulse signal with a frequency of 16~48KHz to the servo motor to control the motor speed, and at the same time give the servo motor a high level signal Control the servo motor to rotate in the positive direction. At this time, the electric actuator moves at a speed of 0.04~0.12m/s in the direction of reducing the position of the clutch to realize the rapid engagement of the clutch. At the same time, it is detected whether the speed of the clutch output shaft is 0, if it is 0 then Repeat step 1, if the speed is not 0, go to step 2;

[0034] Step 2. When the speed of the clutch output shaft is no longer 0, it will enter the slip grinding stage. At this time, a pulse signal with a frequency of 16~48KHz is output to the servo motor to control the motor speed, and a high level signal to the servo motor to control the servo The motor rotates in the forward direction, and the electric actuator continues to move in the direction of decreasing the clutch position at a speed of 0.04~0.12m/s. Collect the engine speed ωe and the clutch output shaft speed ωc, make the difference between the two to obtain the sliding speed ωec, and calculate the sliding speed change rate. When the sliding speed and the sliding speed change rate of the entire engagement process reach the set critical When the point (ωec=700rpm, the rate of change of sliding speed is less than zero), it will enter the step 3.

[0035] Step 3. When it is detected that the sliding speed and the sliding speed change rate of the joining process reach the set critical point, a low-level signal is given to the servo motor to control the reverse movement of the servo motor. At this time, the electric actuator is constant The speed moves to the direction that the clutch position increases, which reduces the engagement pressure before the clutch synchronization, that is, reduces the friction torque before synchronization. When the distance of the reverse increase of the clutch position exceeds 2 mm, the step 4 is entered.

[0036] Step 4. Output a pulse signal with a frequency of 16~48KHz to the servo motor to control the speed of the motor. At the same time, give the servo motor a high level signal to control the positive rotation of the servo motor. At this time, the electric actuator is at a speed of 0.04~0.12m/s. Continue to move to the direction of the reduction of the clutch position to achieve the rapid engagement synchronization of the clutch. In order to prevent the electric actuator from continuing to move and damage the actuator after the clutch synchronization, the clutch position is detected by the limit sensor. When the clutch reaches the minimum limit point (ie set The limit value of 3mm) is the sensor feedback signal, the single-chip control signal is cut off, the motor stops rotating, and the joining process is completed.

[0037] The focus of the present invention is the control of the slipping stage, which is mainly divided into two stages. The initial stage of the slipping process is when the clutch output shaft rotates and reaches the set critical slipping speed point. The clutch is controlled Engage at a faster speed to shorten the sliding grinding time of the entire sliding grinding process, reducing the sliding grinding work and increasing the service life of the clutch. When the sliding speed is lower than the set critical point, it enters the pre-synchronization stage. At this time, the clutch is controlled to move in the reverse direction to reduce the pre-synchronization engagement pressure to reduce the pre-synchronization friction torque to reduce the impact of the clutch engagement process at the time of synchronization .

[0038] After finishing the debugging and compiling of the control program, it was downloaded to a 16-bit microcontroller with FreeScale MC9S12DT128 model through BDM, and the clutch starting process engagement experiment was carried out. Figure 5 Shown are the speed curves of the engine and clutch before and after the control. It can be seen from the figure that the sliding time before and after the control remains basically unchanged, thereby ensuring that the sliding work during the engagement process is not significantly increased. Image 6 Shown is the displacement curve of the electric actuator during the clutch engagement process before and after the control. Figure 7 Shown are the friction torque curves before and after control. It can be seen from the figure that the friction torque at the synchronization point of the clutch after control is lower than that before control. Picture 8 Shown is the shock degree curve of the clutch engagement process. It can be clearly seen from the figure that the shock degree of the synchronization point after control is significantly lower than that before control. Picture 9 Shown is the slip work curve during clutch engagement. It can be clearly seen from the figure that the decrease in friction torque before synchronization reduces the slip work after control, and a satisfactory control effect is achieved.