Pressure closed-loop fault diagnosis and degradation use method for tracked vehicle controlled by electromagnetic valve

Abstract

The invention belongs to the technical field of hydraulic control of special vehicles, and particularly relates to a solenoid valve controlled tracked vehicle pressure closed-loop fault diagnosis and degradation use method, which introduces current closed-loop control, adjusts the duty ratio according to the actual solenoid valve current, and ensures the current stability. Meanwhile, pressure closed-loop control is further introduced in the method, the current of the electromagnetic valve is adjusted in real time, the pressure stability is guaranteed, and the gear shifting smoothness is improved. According to the method, on one hand, fault diagnosis under pressure current double-closed-loop control is achieved, and the fault position is determined; on the other hand, a degradation use strategy under the abnormal condition of the sensor or the signal source can be considered, and vehicle safety is guaranteed.

Description

Technical Field

[0001] The invention belongs to the technical field of special vehicle hydraulic control, and in particular relates to a method for diagnosing and downgrading a pressure closed-loop fault of a tracked vehicle controlled by a solenoid valve. Background Art

[0002] Special vehicle transmission systems usually use solenoid valves for shift control, and the solenoid valve controls the oil filling of the oil cylinder to adjust the friction plate engagement, thereby achieving gear switching. Among them, the proportional solenoid valve commonly used in special vehicles controls the valve core position by controlling the current passing through the coil, adjusts the amount of oil passing through, thereby controlling the oil pressure of the oil cylinder, and then controls the degree of engagement of the friction plate; compared with the switch solenoid valve, it can further control the oil filling process, which has a good effect on alleviating the impact of gear shifting. The commonly used current control method is to use PWM modulation to output a PWM modulation signal of a specific frequency, and control the current passing through the solenoid valve by adjusting the duty cycle. Due to factors such as coil heating and oil temperature, the solenoid valve current corresponding to the same duty cycle is not the same. At this time, it is necessary to introduce current closed-loop control to adjust the duty cycle according to the actual solenoid valve current to ensure current stability. However, the same solenoid valve current will also cause the oil pressure output by the cylinder to change due to changes in oil viscosity, affecting the degree of engagement of the friction plate. Therefore, it is also necessary to introduce pressure closed-loop control to adjust the solenoid valve current in real time to ensure the stability of pressure in order to improve the smoothness of gear shifting. Summary of the invention

[0003] 1. Technical issues to be resolved

[0004] The technical problem to be solved by the present invention is: how to provide a method for diagnosing and degrading pressure closed-loop faults of tracked vehicles based on solenoid valve control.

[0005] (II) Technical solution

[0006] In order to solve the above technical problems, the present invention provides a method for diagnosing and degrading a pressure closed-loop fault of a tracked vehicle controlled by a solenoid valve, and the method is as follows:

[0007] Step 1: First determine the oil pump speed status and make sure the oil source has built up pressure;

[0008] Step 2: Calculate the pressure mean square error σ based on the sensor pressure sampling value P P ;

[0009] Step 3: If the pressure mean square error σ P If the current is less than the set threshold, the control mode is adjusted to the constant pressure mode, the pressure is controlled to be constant, and the expected current value is calculated according to the pressure PID algorithm;

[0010] Step 4: If the pressure mean square error σ PNot less than the set threshold, and then calculate the current mean square error σ based on the current sampling value I I ; At this time, it is judged that the pressure sensor is faulty or the valve block is faulty;

[0011] Step 5: If the current mean square error σ I If the current is less than the set threshold, the control mode is adjusted to the constant current mode, the current is controlled to be constant, and the expected PWM duty cycle is calculated according to the current PID algorithm;

[0012] Step 6: If the current mean square error σ I If it is not less than the set threshold, the control mode is adjusted to the stable PWM output mode, and the PWM output value is set to a fixed value; at the same time, the mean square error σ of the actual PWM output value is calculated. PWM ; At this time, it is judged that the current sampling hardware is faulty;

[0013] Step 7: If the mean square error σ of the actual PWM output value PWM If it is less than the set threshold, the preset PWM duty cycle is output, otherwise the output control mode is a fault and the PWM function is turned off; at this time, the fault is judged to be a microcontroller function failure.

[0014] According to the pressure closed loop fault diagnosis and degradation method, write the single chip control program:

[0015] Step A: Program operation starts;

[0016] Step B: Execute fault degradation strategy judgment, input oil pump speed state, pressure sampling value, current sampling value, PWM actual output value, and obtain control mode and output;

[0017] Step C: determine that the control mode is the constant pressure mode, use the expected pressure value to perform a pressure closed loop to obtain a current value, use the current value to perform a current closed loop to obtain a PWM duty cycle, and output the PWM duty cycle;

[0018] Step D: determining that the control mode is a constant current mode, using a preset current value to perform a current closed loop to obtain a PWM duty cycle, and outputting the PWM duty cycle;

[0019] Step E: Determine that the control mode is stable PWM output, and use a preset PWM duty cycle for output;

[0020] Step F: determine that the control mode is faulty and turn off the PWM function;

[0021] Step G: The program is executed in a cyclical cycle.

[0022] (III) Beneficial effects

[0023] Compared with the prior art, the present invention provides a method for pressure closed-loop fault diagnosis and downgrade use of a tracked vehicle based on solenoid valve control. On the one hand, it realizes fault diagnosis under dual closed-loop control of pressure and current and determines the fault location; on the other hand, it can ensure the downgrade use strategy considering abnormal conditions of sensors or signal sources to ensure vehicle safety. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 It is a flow chart of the fault diagnosis and downgrade method used in the present invention.

[0025] Figure 2 The present invention is a flow chart of the single chip microcomputer software execution method. DETAILED DESCRIPTION

[0026] In order to make the purpose, content, and advantages of the present invention more clear, the specific implementation methods of the present invention are further described in detail below in conjunction with the accompanying drawings and examples.

[0027] In order to solve the above technical problems, the present invention provides a method for diagnosing and degrading a pressure closed-loop fault of a tracked vehicle controlled by a solenoid valve, and the method is as follows:

[0028] Step 1: First determine the oil pump speed status and make sure the oil source has built up pressure;

[0029] Step 2: Calculate the pressure mean square error σ based on the sensor pressure sampling value P P ;

[0030] Step 3: If the pressure mean square error σ P If the current is less than the set threshold, the control mode is adjusted to the constant pressure mode, the pressure is controlled to be constant, and the expected current value is calculated according to the pressure PID algorithm;

[0031] Step 4: If the pressure mean square error σ P Not less than the set threshold, and then calculate the current mean square error σ based on the current sampling value I I ; At this time, it is judged that the pressure sensor is faulty or the valve block is faulty;

[0032] Step 5: If the current mean square error σ I If the current is less than the set threshold, the control mode is adjusted to the constant current mode, the current is controlled to be constant, and the expected PWM duty cycle is calculated according to the current PID algorithm;

[0033] Step 6: If the current mean square error σ I If it is not less than the set threshold, the control mode is adjusted to the stable PWM output mode, and the PWM output value is set to a fixed value; at the same time, the mean square error σ of the actual PWM output value is calculated. PWM ; At this time, it is judged that the current sampling hardware is faulty;

[0034] Step 7: If the mean square error σ of the actual PWM output value PWM If it is less than the set threshold, the preset PWM duty cycle is output, otherwise the output control mode is a fault and the PWM function is turned off; at this time, the fault is judged to be a microcontroller function failure.

[0035] According to the pressure closed loop fault diagnosis and degradation method, write the single chip control program:

[0036] Step A: Program operation starts;

[0037] Step B: Execute fault degradation strategy judgment, input oil pump speed state, pressure sampling value, current sampling value, PWM actual output value, and obtain control mode and output;

[0038] Step C: determine that the control mode is a constant pressure mode, use the expected pressure value to perform a pressure closed loop to obtain a current value, use the current value to perform a current closed loop to obtain a PWM duty cycle, and output the PWM duty cycle;

[0039] Step D: determining that the control mode is a constant current mode, using a preset current value to perform a current closed loop to obtain a PWM duty cycle, and outputting the PWM duty cycle;

[0040] Step E: Determine that the control mode is stable PWM output, and use a preset PWM duty cycle for output;

[0041] Step F: determine that the control mode is faulty and turn off the PWM function;

[0042] Step G: The program is executed in a cyclical cycle.

[0043] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for diagnosing and degrading pressure closed-loop faults of tracked vehicles controlled by a solenoid valve, characterized in that: The method is as follows: Step 1: First determine the oil pump speed status and make sure the oil source has built up pressure; Step 2: Calculate the pressure mean square error σ based on the sensor pressure sampling value P P ; Step 3: If the pressure mean square error σ P If the current is less than the set threshold, the control mode is adjusted to the constant pressure mode, the pressure is controlled to be constant, and the expected current value is calculated according to the pressure PID algorithm; Step 4: If the pressure mean square error σ P Not less than the set threshold, and then calculate the current mean square error σ based on the current sampling value I I ; At this time, it is judged that the pressure sensor is faulty or the valve block is faulty; Step 5: If the current mean square error σ I If the current is less than the set threshold, the control mode is adjusted to the constant current mode, the current is controlled to be constant, and the expected PWM duty cycle is calculated according to the current PID algorithm; Step 6: If the current mean square error σ I If it is not less than the set threshold, the control mode is adjusted to the stable PWM output mode, and the PWM output value is set to a fixed value; at the same time, the mean square error σ of the actual PWM output value is calculated. PWM ; At this time, it is judged that the current sampling hardware is faulty; Step 7: If the mean square error σ of the actual PWM output value PWM If it is less than the set threshold, the preset PWM duty cycle is output, otherwise the output control mode is a fault and the PWM function is turned off; at this time, the fault is judged to be a microcontroller function failure.

2. The method for diagnosing and degrading pressure closed-loop faults of tracked vehicles controlled by a solenoid valve as claimed in claim 1, characterized in that: According to the pressure closed loop fault diagnosis and degradation method, write the single chip control program: Step A: Program operation starts; Step B: Execute fault degradation strategy judgment, input oil pump speed state, pressure sampling value, current sampling value, PWM actual output value, and obtain control mode and output; Step C: determine that the control mode is a constant pressure mode, use the expected pressure value to perform a pressure closed loop to obtain a current value, use the current value to perform a current closed loop to obtain a PWM duty cycle, and output the PWM duty cycle; Step D: determining that the control mode is a constant current mode, using a preset current value to perform a current closed loop to obtain a PWM duty cycle, and outputting the PWM duty cycle; Step E: Determine that the control mode is stable PWM output, and use a preset PWM duty cycle for output; Step F: determine that the control mode is faulty and turn off the PWM function; Step G: The program is executed in a cyclical cycle.

3. The method for diagnosing and degrading pressure closed-loop faults of tracked vehicles controlled by a solenoid valve as claimed in claim 1, characterized in that: The method belongs to the technical field of special vehicle hydraulic control.

4. The method for diagnosing and degrading pressure closed loop faults of tracked vehicles controlled by solenoid valves as claimed in claim 1, characterized in that: The method introduces current closed-loop control and adjusts the duty cycle according to the actual solenoid valve current to ensure current stability.

5. The method for diagnosing and degrading pressure closed-loop faults of tracked vehicles controlled by a solenoid valve as claimed in claim 1, characterized in that: The method introduces pressure closed-loop control and adjusts the solenoid valve current in real time to ensure pressure stability, thereby improving gear shifting smoothness.

6. The method for diagnosing and degrading pressure closed loop faults of tracked vehicles controlled by solenoid valves as claimed in claim 1, characterized in that: The method realizes fault diagnosis under pressure and current double closed-loop control and determines the fault location.

7. The method for diagnosing and degrading pressure closed loop faults of tracked vehicles controlled by solenoid valves as claimed in claim 1, characterized in that: The method can ensure that a downgraded usage strategy is taken into account when a sensor or signal source is abnormal, thereby ensuring vehicle safety.

8. The method for diagnosing and degrading pressure closed loop faults of tracked vehicles controlled by solenoid valves as claimed in claim 1, characterized in that: In step 5, the desired PWM duty cycle is calculated according to the current PID algorithm.

9. The method for diagnosing and degrading pressure closed-loop faults of a tracked vehicle controlled by a solenoid valve as claimed in claim 1, characterized in that: In step 3, the expected current value is calculated according to the pressure PID algorithm.

10. The solenoid valve controlled tracked vehicle pressure closed loop fault diagnosis and degradation method as claimed in claim 1, characterized in that: In step 7, if the mean square error σ of the actual PWM output value PWM If it is less than the set threshold, the preset PWM duty cycle is output, otherwise the output control mode is a fault and the PWM function is turned off; at this time, the fault is judged to be a microcontroller function failure.

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