Wheel speed sensor communication protocol verification method

Abstract

The invention provides a wheel speed sensor communication protocol verification method, which specifically comprises the following steps: detecting a square wave signal acquired and processed by a wheel speed sensor through a wheel speed processing module, identifying the current amplitude of a first pulse, if the current amplitude is within a preset range, judging that the communication protocol type of the wheel speed sensor on the wheel side is an AK protocol, and if the current amplitude is not within the preset range, judging that the communication protocol type of the wheel speed sensor on the wheel side is an AK protocol; if the pulse signal is not in the preset range, monitoring the interval duration with the next pulse signal; and if the interval is within a preset range, determining that the communication protocol type of the wheel-side wheel speed sensor is an AK protocol, and if the interval exceeds the preset range, determining that the communication protocol type of the wheel-side wheel speed sensor is a PWM protocol. Real-time detection and fault diagnosis of the wheel speed signals are achieved through the wheel speed processing module of the vehicle, other equipment does not need to be added, and the detection method is simple and effective. By analyzing the pulse interval and the current amplitude of the wheel speed signal, accurate judgment and positioning of the fault type are realized, and troubleshooting and repair are facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of wheel speed sensor communication, and in particular to a wheel speed sensor communication protocol verification method. Background Art

[0002] As the competition in the passenger car market becomes increasingly fierce, more and more auto parts are developed in a platform-based manner, that is, the same appearance size is adapted to the needs of multiple models. As for wheel speed sensors, the currently mainstream AK (active) wheel speed sensors and PWM (pulse width modulation) wheel speed sensors follow unified standards in terms of physical interface and appearance size, but because they use completely different digital communication protocols, there is a significant risk of mixed / wrong installation in the vehicle assembly process.

[0003] At present, the direct consequences of this technical hidden danger are manifested in two aspects: in terms of signal analysis, the wheel speed signal processing module cannot correctly decode the heterogeneous sensor signal due to protocol mismatch, resulting in distortion or loss of wheel speed information; in terms of system safety, it will cause abnormal wheel speed signal or ABS alarm. Therefore, how to verify the wheel speed sensor communication protocol and timely identify the wheel speed sensor type error has become a technical problem that needs to be solved in this field. Summary of the invention

[0004] In order to solve the above problems, the present invention discloses a wheel speed sensor communication protocol verification method, which can accurately and quickly detect whether the wheel speed sensor communication protocol is correct.

[0005] The specific plan is as follows:

[0006] A wheel speed sensor communication protocol verification method comprises the following steps:

[0007] S1, the wheel speed sensor transmits the collected and processed square wave signal to the wheel speed processing module, and the wheel speed processing module detects the signal;

[0008] S2, when the wheel speed processing module detects a zero-crossing input signal, it identifies the current amplitude of the first pulse. If it is within the preset range, it determines that the communication protocol type of the wheel speed sensor on the wheel side is AK protocol; and compares it with the system default communication protocol type. If they are inconsistent, it immediately reports that the wheel speed sensor communication protocol type is wrong and lights up the ABS warning light;

[0009] S3, if the detected current amplitude is not within the preset range, the interval between the detection current and the next pulse signal is monitored. If the interval is within the preset range, the communication protocol type of the wheel speed sensor is determined to be the AK protocol; and the communication protocol type is compared with the default communication protocol type of the system. If they are inconsistent, the communication protocol type error of the wheel speed sensor is immediately reported, and the ABS warning light is turned on.

[0010] S4: If it is detected that the interval with the next pulse signal exceeds the preset range, the communication protocol type of the wheel speed sensor on the wheel side is determined to be the PWM protocol; and it is compared with the system default communication protocol type. If they are inconsistent, the communication protocol type error of the wheel speed sensor on the wheel side is immediately reported, and the ABS warning light is turned on.

[0011] Furthermore, in step S1, the wheel speed processing module includes a current identification unit and a pulse identification unit.

[0012] Furthermore, in step S2, the preset range of the current amplitude is 23-34 mA.

[0013] Furthermore, in step S3, the preset range of the interval time is 20 to 30 μs.

[0014] Furthermore, in step S4, when the communication protocol type of the wheel speed sensor is inconsistent with the system default type, the ABS warning light will be triggered to remind, and the corresponding fault code will be read through the diagnostic tool.

[0015] Among them, the diagnostic tools include but are not limited to CANScope, X-Analyser, and PROFIBUS.

[0016] The beneficial effects of the present invention are:

[0017] (1) The vehicle's own wheel speed processing module is used to realize real-time detection and fault diagnosis of wheel speed signals without adding other equipment. The detection method is simple and effective.

[0018] (2) By analyzing the wheel speed signal pulse interval and current amplitude, the fault type can be accurately determined and located, facilitating fault detection and repair. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a flow chart of a wheel speed sensor communication protocol verification method of the present invention;

[0020] Figure 2 This is a schematic diagram of the PWM wheel speed sensor waveform;

[0021] Figure 3 This is a waveform diagram of the AK wheel speed sensor with wheel speed;

[0022] Figure 4 This is a waveform diagram of the AK wheel speed sensor in the absence of wheel speed. DETAILED DESCRIPTION

[0023] The present invention will be further explained below in conjunction with specific implementation modes. It should be understood that the following specific implementation modes are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0024] As shown in the figure, the present invention provides a method for verifying the communication protocol of a wheel speed sensor, including the following steps:

[0025] In the first step, the wheel speed sensor transmits the collected and processed square wave signal to the wheel speed processing module, and the current identification unit and the pulse identification unit of the wheel speed processing module respectively detect the signal.

[0026] In the second step, when the current identification unit detects a zero-crossing input signal, it immediately identifies the current amplitude of the first pulse. If it is between 23 mA and 34 mA, it is determined that the communication type of the wheel side wheel speed sensor is the AK protocol. And compare it with the default communication protocol type of the system. If they are inconsistent, it immediately reports an error in the communication type of the wheel side wheel speed sensor and lights up the ABS warning light.

[0027] In the third step, if the detected current amplitude is not between 23 mA and 34 mA, then monitor the interval duration Δt with the next pulse signal. If the interval duration Δt is between 20 μs and 30 μs, it is determined that the communication type of the wheel side wheel speed sensor is the AK protocol. And compare it with the default communication protocol type of the system. If they are inconsistent, it immediately reports an error in the communication type of the wheel side wheel speed sensor and lights up the ABS warning light.

[0028] In the fourth step, if the detected interval Δt with the next pulse signal exceeds 30 μs, it is determined that the communication type of the wheel side wheel speed sensor is the PWM protocol. And compare it with the default communication protocol type of the system. If they are inconsistent, it immediately reports an error in the communication type of the wheel side wheel speed sensor and lights up the ABS warning light.

[0029] Specifically, when the ABS warning light is lit due to a communication type error, the corresponding fault code can be read through a diagnostic tool.

[0030] Working principle: The pulse intervals and current amplitudes of the wheel speed signals of the AK protocol and the PWM protocol are different. When there is wheel speed, the AK wheel speed sensor outputs a speed pulse with an amplitude between 23 mA and 34 mA. When there is no wheel speed, the amplitude of the speed pulse of the AK protocol is between 11 mA and 17 mA, which is roughly equivalent to the PWM protocol. At this time, it is necessary to further judge according to the next pulse interval duration Δt. After the speed pulse of the AK protocol, a data information pulse will be sent within an interval of 20 μs to 30 μs, while the duration interval of the next pulse of the PWM protocol requires a longer time.

[0031] The technical means disclosed by the solution of the present invention are not limited to the technical means disclosed in the above embodiments, but also include technical solutions composed of any combination of the above technical features. It should be noted that for those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and modifications can be made, and these improvements and modifications are also regarded as the protection scope of the present invention.

Claims

1. A method for verifying a wheel speed sensor communication protocol, characterized in that, It includes the following steps: S1. The wheel speed sensor transmits the collected and processed square wave signal to the wheel speed processing module, and the wheel speed processing module detects the signal; S2. When the wheel speed processing module detects a zero-crossing input signal, it identifies the current amplitude of the first pulse. If it is within the preset range, it determines that the communication protocol type of the wheel side wheel speed sensor is the AK protocol; and compares it with the communication protocol type default in the system. If they are inconsistent, it immediately reports an error in the communication protocol type of the wheel side wheel speed sensor and lights up the ABS warning light; S3. If the detected current amplitude is not within the preset range, it monitors the interval duration with the next pulse signal. If the interval is within the preset range, it determines that the communication protocol type of the wheel side wheel speed sensor is the AK protocol; and compares it with the communication protocol type default in the system. If they are inconsistent, it immediately reports an error in the communication protocol type of the wheel side wheel speed sensor and lights up the ABS warning light; S4. If the detected interval with the next pulse signal exceeds the preset range, it determines that the communication protocol type of the wheel side wheel speed sensor is the PWM protocol; and compares it with the communication protocol type default in the system. If they are inconsistent, it immediately reports an error in the communication protocol type of the wheel side wheel speed sensor and lights up the ABS warning light.

2. The wheel speed sensor communication protocol verification method according to claim 1, characterized in that In the step S1, the wheel speed processing module includes a current identification unit and a pulse identification unit.

3. A wheel speed sensor communication protocol verification method according to claim 1, characterized in that In the step S2, the preset range of the current amplitude is 23-34 mA.

4. A wheel speed sensor communication protocol verification method according to claim 1, characterized in that In the step S3, the preset range of the interval duration is 20-30 μs.

5. A wheel speed sensor communication protocol verification method according to claim 1, characterized in that In the step S4, when the communication protocol type of the wheel speed sensor is inconsistent with the default type in the system, it will trigger the ABS warning light to give a reminder, and at the same time read the corresponding fault code through a diagnostic tool.

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