A method and system for diagnosing throttle pedal sticking

Abstract

The present invention discloses a method and system for diagnosing a stuck accelerator pedal. When a braking signal of a vehicle is detected, an angular displacement signal of the accelerator pedal within a set time period before the generation of the braking signal is obtained; the viscous damping coefficient of the accelerator pedal is calculated according to the angular displacement signal of the accelerator pedal; it is determined whether the viscous damping coefficient meets the set conditions; if the set conditions are met, it is considered that the accelerator pedal is stuck. Using the method or system of the present invention, it is possible to quickly determine whether the accelerator pedal has a risk of damping stuck failure, so that the driver and passengers can be informed and warned that the accelerator pedal has a fault and reminded to replace and repair it as soon as possible. The vehicle can also take active downgrade measures such as limiting power or vehicle speed according to the frequency of the fault, so as to minimize the potential risk level caused by component failure and improve the safety of vehicle driving.

Description

Technical Field

[0001] The present invention belongs to the technical field of vehicle accelerator pedal sticking diagnosis, and in particular relates to an accelerator pedal sticking diagnosis method and system. Background Art

[0002] Modern cars generally obtain pedal stroke signals through the angle sensor of the electronic accelerator pedal to identify the driver's acceleration intention. In the design of the accelerator pedal, in order to make the driver feel good and reduce the noise caused by releasing the pedal and impacting the stroke limit point, a damping device is usually designed in the rotating structure. As the use fails, the sliding surface characteristics of the rotating structure change. For example, the wear of the damping material causes surface roughness and micro-dimensional changes, which may cause the damping to increase. As a result, the pedal cannot rebound in time after releasing the accelerator pedal, causing serious hysteresis of the accelerator pedal signal, exceeding the acceleration torque expected by the driver. This risk belongs to the highest level risk in vehicle functional safety.

[0003] One of the difficulties in diagnosing this problem is how to confirm whether the accelerator pedal has driver intervention during the rebound process (the right foot has not completely left the pedal) or whether the accelerator pedal is rebounding freely (the right foot has completely left the pedal). The more likely solution is to add a stress sensing device to the pedal surface, which increases hardware, and most cars are not equipped with stress sensing devices. Therefore, this solution increases costs, resulting in low commercial competitiveness. Therefore, similar solutions are rarely applied to vehicles. The second difficulty in diagnosing this problem is how to identify changes in the damping characteristics to confirm that the component has failed. Summary of the invention

[0004] In order to identify whether the accelerator pedal fails to rebound in time after the accelerator pedal is released due to damping failure, thereby causing a risk of exceeding the acceleration torque expected by the driver, the present invention provides a diagnosing method and system for accelerator pedal sticking.

[0005] A method for diagnosing a stuck accelerator pedal to achieve one of the objectives of the present invention comprises:

[0006] When a braking signal of the vehicle is detected, an angular displacement signal of the accelerator pedal within a set time period before the braking signal is generated is obtained; a viscous damping coefficient of the accelerator pedal is calculated based on the angular displacement signal of the accelerator pedal; and it is determined whether the viscous damping coefficient meets a set condition; if the set condition is met, it is considered that the accelerator pedal is stuck.

[0007] The angular displacement signal of the accelerator pedal can be obtained from the vehicle VCU, and the angular displacement signal of the accelerator pedal is sent to the vehicle VCU in real time and saved; the accelerator pedal is in a free rebound state within the set time.

[0008] Furthermore, the method for determining whether the viscous damping coefficient meets the set condition includes:

[0009] The effective values ​​of all viscous damping coefficients within the set time are obtained; when the number of viscous damping coefficients within the set range exceeds the set ratio, and the average of the effective values ​​of the viscous damping coefficients is greater than or equal to the first set threshold, it is considered that the set condition is met.

[0010] Furthermore, the method for determining the effective value of the viscous damping coefficient includes: when the angular displacement signal θ of the accelerator pedal i Greater than the set value, angular velocity When it is less than the set value, the value of the viscous damping coefficient is considered to be an effective value.

[0011] Furthermore, a method for calculating the viscous damping coefficient of the accelerator pedal according to the angular displacement signal of the accelerator pedal includes:

[0012]

[0013] Where:

[0014] C i is the viscous damping coefficient at time i;

[0015] K is the stiffness coefficient of the return spring;

[0016] θ i is the angular displacement signal of the accelerator pedal at time i;

[0017] J is the moment of inertia of the pedal lever body around the rotation axis;

[0018] is the angular velocity of the accelerator pedal at time i; when calculating, the value is the first-order derivative of the angular displacement signal of the accelerator pedal;

[0019] is the angular acceleration of the accelerator pedal at time i; when calculating, it is taken as the second-order derivative of the angular displacement signal of the accelerator pedal.

[0020] Furthermore, in order to further improve the accuracy of the accelerator pedal stuck judgment, it is also possible to judge whether the accelerator pedal is stuck based on the time when the accelerator pedal travel falls back. The method for diagnosing pedal stuck also includes: starting the timing when the vehicle's braking signal is detected and the accelerator pedal's angular displacement signal is greater than a second set threshold, and ending the timing when the accelerator pedal's angular displacement signal is 0 or reaches the set time length. If the timing length is greater than a third set threshold, it is considered that the accelerator pedal is stuck. When the accelerator pedal's angular displacement signal is 0, the accelerator pedal is in a fully released state.

[0021] Furthermore, in order to avoid abnormal angle sensor signals, such as rising or stagnating, which may lead to inaccurate judgment, in order to further improve the accuracy of the judgment of throttle pedal stuck, it is necessary to further judge whether the falling characteristics of the stroke signal of the angle sensor of the throttle pedal are normal. The falling of the stroke signal means: when the throttle pedal is fully stepped on, the stroke is 100%, and when the throttle pedal is fully released, the stroke is 0, so the process from stepping on to releasing is called the falling of the stroke signal. The method for judging pedal stuck according to the falling characteristics of the stroke signal also includes: within the timing duration, calculating the difference between the angular displacement signals of the throttle pedal at two adjacent moments, if the angular displacement signal at the latter moment is less than or equal to the fourth set threshold value and the difference is greater than the fifth set threshold value, then the angular displacement signal of the throttle pedal is considered abnormal, and then the throttle pedal is considered stuck. The abnormality includes rising and stagnating of the throttle pedal.

[0022] Furthermore, the difference is calculated as the difference between the angular displacement signal of the accelerator pedal at a previous moment and the angular displacement signal of the accelerator pedal at a later moment.

[0023] The throttle pedal stuck diagnostic system for achieving the second purpose of the present invention includes: a first throttle pedal stuck diagnostic module, which is used to obtain the angular displacement signal of the throttle pedal within a set time period before the braking signal is generated when the vehicle's braking signal is detected; calculate the viscous damping coefficient of the throttle pedal based on the angular displacement signal of the throttle pedal; determine whether the viscous damping coefficient meets the set conditions; if the set conditions are met, it is considered that the throttle pedal is stuck.

[0024] Furthermore, it also includes a viscous damping coefficient characteristic judgment module, which is used to obtain the effective values ​​of all viscous damping coefficients within the set time length; when the number of viscous damping coefficients within the set range exceeds the set ratio, and the average of the effective values ​​of the viscous damping coefficients is greater than or equal to the first set threshold, it is considered that the set conditions are met.

[0025] Furthermore, it also includes a second accelerator pedal stuck diagnostic module, which is used to start timing when the vehicle's braking signal is detected and the angular displacement signal of the accelerator pedal is greater than a second set threshold, and end timing when the angular displacement signal of the accelerator pedal is 0 or reaches the set time length. If this timing duration is greater than a third set threshold, it is considered that the accelerator pedal is stuck.

[0026] Furthermore, it also includes a third accelerator pedal sticking diagnostic module, which is used to calculate the difference between the angular displacement signals of the accelerator pedal at two adjacent moments within the timing period; if the angular displacement signal at the latter moment is less than or equal to a fourth set threshold and the difference is greater than a fifth set threshold, it is considered that the angular displacement signal of the accelerator pedal is abnormal.

[0027] By utilizing the system and method described in the present invention, it is possible to quickly determine whether the accelerator pedal has a risk of damping sticking failure, thereby being able to inform and warn the driver and passengers that the accelerator pedal is faulty and remind them to replace and repair it as soon as possible. The vehicle can also take active downgrade measures such as limiting power or speed based on the frequency of the fault, thereby minimizing the potential risk level caused by component failure and improving the safety of vehicle driving. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 It is a schematic diagram of the process of the method of the present invention. DETAILED DESCRIPTION

[0029] The following specific implementations are used to explain the technical solutions of the claims of the present invention so that those skilled in the art can understand the claims. The protection scope of the present invention is not limited to the following specific implementation structures. The technical solutions of the claims of the present invention made by those skilled in the art but different from the following specific implementations are also within the protection scope of the present invention.

[0030] In the description of the present invention, the terms "first", "second", etc. are only used to distinguish the descriptions and cannot be understood as indicating or implying relative importance.

[0031] Combine the following Figure 1 An embodiment of the method of the present invention is described.

[0032] When a braking signal of the vehicle is detected, an angular displacement signal of the accelerator pedal within 400ms before the braking signal is generated is obtained; a viscous damping coefficient of the accelerator pedal is calculated according to the angular displacement signal of the accelerator pedal; and it is determined whether the viscous damping coefficient meets a set condition; if the set condition is met, it is considered that the accelerator pedal is stuck.

[0033] The specific calculation method of the viscous damping coefficient is as follows:

[0034] The accelerator pedal angle sensor senses voltage information to represent the angle, and the angle information is obtained by conversion; the accelerator pedal angle information is recorded as θ, and the first-order derivative can be used to calculate the angular velocity based on the continuous signal Find the second derivative to calculate angular acceleration The relationship between the three can be expressed using the dynamic mechanical equilibrium formula:

[0035]

[0036] Where:

[0037] J: represents the moment of inertia of the pedal lever body around the rotation axis, which is a physical constant;

[0038] K: represents the stiffness coefficient of the return spring, which is a constant;

[0039] C: is the viscous damping coefficient to be calculated.

[0040] Therefore, the method for estimating the viscous damping coefficient according to the angular displacement signal sent by the angle sensor is as follows: the viscous damping coefficient C at each moment within the first 400 ms is i for:

[0041]

[0042] The method for determining whether the viscous damping coefficient meets the set condition includes:

[0043] When the accelerator pedal angular displacement signal θ i Greater than 0, angular velocity When the viscous damping coefficient is less than 0, the value of the viscous damping coefficient is considered to be a valid value, and the valid value of the viscous damping coefficient within the 400ms is obtained, that is, the valid results of the accelerator pedal at each moment within the 400ms are counted; when more than 70% of the values ​​of the viscous damping coefficient fall within In the range, is the mean of the valid results, and If the value is greater than or equal to a first set threshold value, which in this embodiment is 0.17, it is considered that the accelerator pedal is stuck.

[0044] The above description of the 400ms time is as follows:

[0045] In order to prevent the driver from stepping on the accelerator pedal and the brake pedal at the same time with his right foot, the accelerator pedal is usually arranged at a lower position and the brake pedal is arranged at a higher position, and the space distance is used to prevent misoperation, so that it takes a certain amount of time for the driver to step on the brake when the right foot leaves the accelerator pedal. Therefore, when the brake pedal is detected and the accelerator pedal is in a rebound state, there is a short period of time when the driver's right foot is used to move, and the accelerator pedal is in a state without driver interference. Usually, the time required for the driver's right foot to leave the accelerator and step on the brake can be measured from the test. Select healthy young drivers to switch between the accelerator and the brake for multiple times, and the shortest time required to leave the accelerator and step on the brake can be obtained. In this embodiment, this time is set to 400ms after measurement. Then, when the subsequent activation signal analysis is performed, the data before 400ms is analyzed and processed. During this time period, the accelerator pedal is in a free rebound state. According to the free rebound state of the accelerator pedal during this time period, it is judged whether the accelerator pedal has damping stagnation.

[0046] In another embodiment, in order to further improve the accuracy of the accelerator pedal stuck judgment, the validity of the signal length may be further judged, and the specific method is as follows:

[0047] When the angular displacement signal of the accelerator pedal is greater than the second set threshold, the timing starts, and when the angular displacement signal of the accelerator pedal is 0, the timing ends. If the timing duration is greater than the third set threshold, the accelerator pedal is considered to be stuck. In this embodiment, the second set threshold is 0.1, and the third set threshold is 250ms, that is, at the moment of receiving the brake signal, if θ≥0.1, the timing starts, and when θ=0 or 400ms has expired, the timing ends. If the timing duration t≥250ms, the accelerator pedal is determined to be stuck.

[0048] Preferably, in order to further improve the accuracy of the accelerator pedal stuck judgment, it is further judged whether the drop characteristics of the stroke signal of the accelerator pedal angle sensor are normal. The stroke signal drop means that when the accelerator pedal is fully depressed, the stroke is 100%, and when the accelerator pedal is fully released, the stroke is 0. Then the process from depression to release is called signal drop. The specific method is as follows:

[0049] During the above timing period, the difference between the angular displacement signals of the accelerator pedal at two adjacent moments is calculated. If the angular displacement signal at the latter moment is less than or equal to the fourth set threshold and the difference is greater than the fifth set threshold, it is considered that the accelerator pedal is stuck. In this embodiment, the fourth set threshold is 0.1 and the fifth set threshold is 0.0015; that is, θ k-1 -θ k ≥0.0015Calculation starts, when θ k When ≤0.1, the calculation is terminated. If the above conditions are met before the calculation is terminated, the accelerator pedal is considered to be stuck.

[0050] It should be understood that the size of the serial numbers of the steps in the above embodiments does not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation on the implementation process of the embodiments of the present application.

[0051] The present application also provides an embodiment of an accelerator pedal stuck diagnostic system, including a first accelerator pedal stuck diagnostic module, which is used to obtain an angular displacement signal of the accelerator pedal within 400ms before the braking signal is generated when a vehicle braking signal is detected; calculate the viscous damping coefficient of the accelerator pedal based on the angular displacement signal of the accelerator pedal; determine whether the viscous damping coefficient meets set conditions; if the set conditions are met, it is considered that the accelerator pedal is stuck.

[0052] In another embodiment, a viscous damping coefficient characteristic judgment module is further included, which is used to obtain the effective values ​​of all viscous damping coefficients within the 400ms; when the value of the viscous damping coefficient is The number of values ​​within the range exceeds 70%, and the mean of the effective values ​​of the viscous damping coefficient If it is greater than or equal to 0.17, it is considered to meet the set conditions.

[0053] In another embodiment, a second accelerator pedal stuck diagnostic module is also included, which is used to start timing when the vehicle's braking signal is detected and the angular displacement signal of the accelerator pedal is greater than 0.1, and end timing when the angular displacement signal of the accelerator pedal is 0 or reaches 400ms. If this timing duration is greater than a third set threshold, the accelerator pedal is considered to be stuck.

[0054] In another embodiment, a third accelerator pedal stuck diagnostic module is further included, which is used to calculate the difference between the angular displacement signals θ of the accelerator pedal at two adjacent moments within 400ms. If the angular displacement signal at the latter moment is less than or equal to 0.1 and the difference is greater than 0.0015, then θ is satisfied. k-1 -θ k ≥0.0015, the angular displacement signal of the accelerator pedal is considered abnormal.

Claims

1. A method for diagnosing a stuck accelerator pedal, characterized in that: When a braking signal of the vehicle is detected, an angular displacement signal of the accelerator pedal within a set time period before the braking signal is generated is obtained; a viscous damping coefficient of the accelerator pedal is calculated according to the angular displacement signal of the accelerator pedal; and it is determined whether the viscous damping coefficient meets a set condition; If the set conditions are met, the accelerator pedal is considered to be stuck; The method for calculating the viscous damping coefficient of the accelerator pedal according to the angular displacement signal of the accelerator pedal comprises: Where: C i for i The viscous damping coefficient at time ; K is the stiffness coefficient of the return spring; θ i for i The angular displacement signal of the accelerator pedal at the moment; J is the moment of inertia of the pedal lever body around the rotation axis; for i The angular velocity of the accelerator pedal at the moment; for i The angular acceleration of the accelerator pedal at time .

2. The accelerator pedal stuck diagnosis method according to claim 1, characterized in that: The method for judging whether the viscous damping coefficient meets the set condition includes: The effective values ​​of all viscous damping coefficients within the set time are obtained; when the number of viscous damping coefficients within the set range exceeds the set ratio, and the average of the effective values ​​of the viscous damping coefficients is greater than or equal to the first set threshold, it is considered that the set condition is met.

3. The accelerator pedal stuck diagnosis method according to claim 2, characterized in that: The method for determining the effective value of the viscous damping coefficient includes: when the angular displacement signal of the accelerator pedal θ i Greater than the set value, angular velocity When it is less than the set value, the value of the viscous damping coefficient is considered to be an effective value.

4. The accelerator pedal stuck diagnosis method according to claim 1, characterized in that: The accelerator pedal stuck diagnostic method also includes: starting timing when a vehicle braking signal is detected and an angular displacement signal of the accelerator pedal is greater than a second set threshold, and ending timing when the angular displacement signal of the accelerator pedal is 0 or reaches the set time length, and if this timing length is greater than a third set threshold, it is considered that the accelerator pedal is stuck.

5. The accelerator pedal stuck diagnosis method according to claim 4, characterized in that: The accelerator pedal stuck diagnosis method also includes: within the timing duration, calculating the difference in angular displacement signals of the accelerator pedal at two adjacent moments, and if the angular displacement signal at the latter moment is less than or equal to a fourth set threshold and the difference is greater than a fifth set threshold, it is considered that the accelerator pedal is stuck.

6. A throttle pedal stuck diagnostic system for implementing the method as claimed in claim 1, characterized in that: It includes a first accelerator pedal stuck diagnostic module, which is used to obtain the angular displacement signal of the accelerator pedal within a set time period before the braking signal is generated when the vehicle's braking signal is detected; calculate the viscous damping coefficient of the accelerator pedal according to the angular displacement signal of the accelerator pedal; determine whether the viscous damping coefficient meets the set conditions; if the set conditions are met, it is considered that the accelerator pedal is stuck.

7. The accelerator pedal stuck diagnostic system according to claim 6, characterized in that: It includes a viscous damping coefficient characteristic judgment module, which is used to obtain the effective values ​​of all viscous damping coefficients within the set time length; when the number of viscous damping coefficients within the set range exceeds the set ratio, and the average of the effective values ​​of the viscous damping coefficients is greater than or equal to the first set threshold, it is considered that the set conditions are met.

8. The accelerator pedal stuck diagnostic system according to any one of claims 6 to 7, characterized in that: It also includes a second accelerator pedal stuck diagnostic module, which is used to start timing when the vehicle's braking signal is detected and the angular displacement signal of the accelerator pedal is greater than a second set threshold, and end timing when the angular displacement signal of the accelerator pedal is 0 or reaches the set time length. If this timing duration is greater than a third set threshold, it is considered that the accelerator pedal is stuck.

9. The accelerator pedal stuck diagnostic system according to claim 8, characterized in that: It also includes a third accelerator pedal stuck diagnostic module, which is used to calculate the difference in the angular displacement signal of the accelerator pedal at two adjacent moments within the timing duration. If the angular displacement signal at the latter moment is less than or equal to a fourth set threshold and the difference is greater than a fifth set threshold, it is considered that the angular displacement signal of the accelerator pedal is abnormal.

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