Signal acquisition and processing system compatible with various automobile wheel speed sensors

Abstract

The invention discloses a signal acquisition and processing system compatible with various automobile wheel speed sensors, which comprises an external wheel speed signal input module, a reference voltage generation module and a comparison output module, and is characterized in that the external wheel speed signal input module is electrically connected with the comparison output module; and the reference voltage generation module is electrically connected with the comparison output module. According to the signal collecting and processing system compatible with the multiple automobile wheel speed sensors, the purpose that the same circuit is compatible with wheel speed signal analysis of the three wheel speed sensors is achieved through voltage conversion in the second resistance value adjusting device, and wheel speed voltage signals are compared with different reference voltages through the comparator; and the output of a wheel speed signal and the diagnosis of open circuit, short circuit to ground, short circuit to a power supply and overcurrent of a wheel speed sensor signal can be carried out, so that the whole circuit is more reliable in use.

Description

Technical Field

[0001] The invention belongs to the technical field of wheel speed sensor signal acquisition, and in particular relates to a signal acquisition and processing system compatible with a variety of automobile wheel speed sensors. Background Art

[0002] The automobile wheel speed signal analysis circuit is a key part in automobile safety and performance control. With the rapid development of the automobile industry and the improvement of intelligent demand, the design of the wheel speed signal analysis circuit is also constantly improving and perfecting.

[0003] Currently, wheel speed sensors have been widely used in various types of automobiles. Their main function is to provide information on wheel speed, which is essential for the realization of vehicle stable driving, braking system, hill hold assist system and other functions. The popular active wheel speed sensors on the market are divided into three types: Type 1, Type 2, and Type 3. The information provided by the wheel speed sensor helps the system identify whether the vehicle is slipping or losing control, and adjusts the engine torque output and brake pressure accordingly to restore or maintain the vehicle's stable driving.

[0004] In the related art, for example, CN111983343A discloses a current type wheel speed sensor acquisition circuit, which has a simple circuit structure and can comprehensively detect various possible faults of the current type wheel speed sensor. However, in the related art, the signal acquisition system of the wheel speed sensor is difficult to design with a single analog circuit and cannot be compatible with the wheel speed signal analysis of three wheel speed sensors. Summary of the invention

[0005] The purpose of the present invention is to provide a signal acquisition and processing system compatible with multiple automobile wheel speed sensors, so as to solve the problem that the signal acquisition system of the wheel speed sensor is difficult to design with a single analog circuit and cannot be compatible with the wheel speed signal analysis of three wheel speed sensors.

[0006] To this end, the present invention provides a signal acquisition and processing system compatible with a variety of automobile wheel speed sensors, comprising:

[0007] An external wheel speed signal input module, a reference voltage generating module and a comparison output module, wherein the external wheel speed signal input module is electrically connected to the comparison output module, the reference voltage generating module is electrically connected to the comparison output module, the external wheel speed signal input module is used to connect to a wheel speed sensor to collect a wheel speed signal, the reference voltage generating module is used to generate a reference voltage, and the comparison output module is used to output a voltage.

[0008] Preferably, the external wheel speed signal input module includes a TVS tube, a third capacitor and a first resistance adjustment device connected in sequence through a circuit, and the TVS tube, the third capacitor and the first resistance adjustment device are respectively connected to the ground wire. The external wheel speed signal input module clamps the wheel speed signal through the TVS tube and filters it through the third capacitor, and converts the current signal into a voltage signal through the first resistance adjustment device to be input to the subsequent comparison circuit for comparison.

[0009] Preferably, the first resistance adjustment device comprises a seventh resistor and an eighth resistor connected in series, and a first switch is connected in parallel at both ends of the eighth resistor.

[0010] Preferably, the reference voltage generating module comprises a voltage dividing device, a voltage follower and a second resistance adjusting device, the voltage dividing device is electrically connected to the voltage follower, and the voltage follower is electrically connected to the second resistance adjusting device.

[0011] Preferably, the voltage divider device includes a first resistor, a second resistor and a first capacitor, the first resistor is electrically connected to the second resistor, the first resistor is connected to a power supply, the second resistor is connected to a ground wire, a first capacitor is connected in parallel at both ends of the second resistor, and the first capacitor is electrically connected to the voltage follower.

[0012] Preferably, the second resistance adjusting device comprises a third resistor, a fourth resistor, a fifth resistor and a sixth resistor connected in sequence through a circuit, the sixth resistor is connected to a ground wire, and a single-pole double-throw analog switch is connected in parallel at both ends of the fifth resistor. The second resistance adjusting device is used to generate the comparison voltage required by the four comparators of the comparison output module, and outputs one of the two comparison voltages through the single-pole double-throw analog switch, so as to solve the problem that the first comparator needs different comparison voltages when switching different wheel speed type signals.

[0013] Preferably, the comparison output module includes a first comparator, a second comparator, a third comparator and a fourth comparator connected in parallel, wherein the positive electrodes of the first comparator, the second comparator, the third comparator and the fourth comparator are electrically connected to the external wheel speed signal input module, and the negative electrodes of the first comparator, the second comparator, the third comparator and the fourth comparator are electrically connected to the reference voltage generation module. By comparing the wheel speed voltage signal with different reference voltages through the comparator, the wheel speed signal can be output and the wheel speed sensor signal can be diagnosed as open circuit, short circuit to ground, short circuit to power supply and overcurrent.

[0014] Preferably, the second comparator and the third comparator are connected via an XOR gate.

[0015] Preferably, each of the first comparator, the second comparator, the third comparator and the fourth comparator is connected to a stabilizing device.

[0016] Preferably, the stabilizing device comprises a pull-up resistor and a stabilizing capacitor, the pull-up resistor is connected to a power supply, and the stabilizing capacitor is connected to a ground line.

[0017] Beneficial effects:

[0018] 1. The present invention provides a signal acquisition and processing system that is compatible with a variety of automobile wheel speed sensors. The voltage conversion in the second resistance adjustment device realizes the wheel speed signal analysis compatible with three wheel speed sensors in the same circuit, and compares the wheel speed voltage signal with different reference voltages through a comparator, which can output the wheel speed signal and diagnose the open circuit, short circuit to ground, short circuit to power supply and overcurrent of the wheel speed sensor signal, making the entire circuit more reliable when used.

[0019] 2. In the present invention, the wheel speed signal is clamped and protected by the TVS tube and filtered by the third capacitor through the external wheel speed signal input module, and the current signal is converted into a voltage signal through the first resistance adjustment device for input to the subsequent comparison circuit for comparison, thereby improving the reliability and stability of wheel speed signal collection.

[0020] 3. The present invention uses a discrete analysis circuit, which improves the flexibility of the circuit, does not require the use of a chip for analysis, and reduces the dependence on the wheel speed analysis chip. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0022] Figure 1 This is a system circuit diagram of Embodiment 1 of a signal acquisition and processing system compatible with multiple automobile wheel speed sensors in the present invention;

[0023] Figure 2 This is a system circuit diagram of an external wheel speed signal input module of Embodiment 1 of a signal acquisition and processing system compatible with multiple vehicle wheel speed sensors in the present invention;

[0024] Figure 3 A circuit diagram of a reference voltage generation module system of Embodiment 1 of a signal acquisition and processing system compatible with multiple automobile wheel speed sensors in the present invention;

[0025] Figure 4 A comparison output module system circuit diagram of Embodiment 2 of a signal acquisition and processing system compatible with multiple automobile wheel speed sensors in the present invention;

[0026] Figure 5 It is a collection signal diagram of Type 1 and Type 2 of Embodiment 2 of a signal collection and processing system compatible with multiple automobile wheel speed sensors in the present invention;

[0027] Figure 6 This is a Type 3 acquisition signal diagram of Example 2 of a signal acquisition and processing system compatible with multiple automobile wheel speed sensors in the present invention.

[0028] In the figure, 1-external wheel speed signal input module, 11-TVS tube, 12-third capacitor, 13-first resistance adjustment device, 131-seventh resistor, 132-eighth resistor, 133-first switch, 2-reference voltage generation module, 21-voltage divider, 211-first resistor, 212-second resistor, 213-first capacitor, 22-voltage follower, 23-second resistance adjustment device, 231-third resistor, 232-fourth resistor, 233-fifth resistor, 234-sixth resistor, 23 5-single-pole double-throw analog switch, 3-comparison output module, 31-first comparator, 32-second comparator, 33-third comparator, 34-fourth comparator, 35-first stabilizing device, 351-ninth resistor, 352-fourth capacitor, 36-second stabilizing device, 361-tenth resistor, 362-tenth resistor, 37-third stabilizing device, 371-eleventh resistor, 372-sixth capacitor, 38-fourth stabilizing device, 381-twelfth resistor, 382-seventh capacitor, 39-XOR gate. DETAILED DESCRIPTION

[0029] The content of the present invention can be more easily understood by selecting the following detailed description of the preferred implementation method of the present invention and the embodiments included. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those of ordinary skill in the art to which the present invention belongs. When there is a conflict, the definition in this specification shall prevail.

[0030] Embodiment 1:

[0031] At present, the popular active wheel speed sensors on the market are divided into three types: Type 1, Type 2 and Type 3. Type 1 is a non-intelligent wheel speed sensor. The current waveform it outputs is a square wave signal with alternating high and low currents with a duty cycle of 50%. Among them, the typical value of high current IH is 14mA, and the typical value of low current IL is 7mA. Type 2 is a PWM protocol intelligent wheel speed sensor. This type of sensor outputs additional information through pulse width modulation, including changes in the installation air gap and information on the forward and reverse rotation of the wheel. Its typical value of high current IH is 14mA, and the typical value of low current IL is 7mA. Type 3 is an AK protocol intelligent wheel speed sensor. This type of sensor provides additional information through a sequence of current square waves, including whether the air gap is normal and whether the air gap is too large or too small when there is an error, the validity of the wheel forward and reverse rotation information and air gap error information, and parity bits. Each group of square waves contains a speed pulse and eight bits of additional information data. The typical value of its speed pulse high current IH is 28mA, the typical value of the additional information data bit current IM is 14mA, and the typical value of the low current IL is 7mA.

[0032] like Figure 1-4 A signal acquisition and processing system compatible with a variety of vehicle wheel speed sensors is shown, comprising:

[0033] An external wheel speed signal input module 1, a reference voltage generating module 2 and a comparison output module 3, wherein the external wheel speed signal input module 1 is electrically connected to the comparison output module 3, and the reference voltage generating module 2 is electrically connected to the comparison output module 3. The external wheel speed signal input module 1 is used to connect to the wheel speed sensor to collect the wheel speed signal, the reference voltage generating module 2 is used to generate a reference voltage, and the comparison output module 3 is used to output a voltage.

[0034] like Figure 2As shown, the external wheel speed signal input module 1 includes a TVS tube 11, a third capacitor 12 and a first resistance adjustment device 13 connected in sequence through a circuit, and the TVS tube 11, the third capacitor 12 and the first resistance adjustment device 13 are respectively connected to the ground wire. The first resistance adjustment device 13 includes a seventh resistor 131 and an eighth resistor 132 connected in series, and a first switch 133 is connected in parallel at both ends of the eighth resistor 132. The external wheel speed signal input module 1 performs clamping protection on the wheel speed signal through the TVS tube 11 and filtering by the capacitor, and converts the current signal into a voltage signal through the first resistance adjustment device 13 to be input to the subsequent comparison circuit for comparison. Since the same module needs to be compatible with wheel speed sensors with different output current sizes, it is necessary to select the resistance of the first resistance adjustment device 13. When using a Type 1 or Type 2 wheel speed sensor, the first resistance adjustment device 13 selects 100Ω, and when using a Type 3 wheel speed sensor, the first resistance adjustment device 13 selects 50Ω, so that the subsequent outputs of the same comparator are all wheel speed signals or additional information signals. The seventh resistor 131 and the eighth resistor 132 are both 50Ω resistors. When a Type 1 or Type 2 wheel speed sensor is used and a 100Ω resistor is required, SW-EN is controlled to make the first switch 133 non-conductive; when a Type 3 wheel speed sensor is used and a 50Ω resistor is required, SW-EN is controlled to make the first switch 133 conductive. In this way, the hardware circuit switching of different wheel speed types is completed, and the same circuit is compatible with the analysis of three different types of wheel speed sensor signals.

[0035] like Figure 3As shown, the reference voltage generating module 2 includes a voltage divider 21, a voltage follower 22 and a second resistance adjusting device 23. The voltage divider 21 is electrically connected to the voltage follower 22, and the voltage follower 22 is electrically connected to the second resistance adjusting device 23. The voltage divider 21 includes a first resistor 211, a second resistor 212 and a first capacitor 213. The first resistor 211 is electrically connected to the second resistor 212. The first resistor 211 is connected to the power supply, the second resistor 212 is connected to the ground line, the first capacitor 213 is connected in parallel at both ends of the second resistor 212, and the first capacitor 213 is electrically connected to the voltage follower 22. The second resistance adjusting device 23 includes a third resistor 231, a fourth resistor 232, a fifth resistor 233 and a sixth resistor 234 connected in sequence through a circuit. The sixth resistor 234 is connected to the ground line, and a single-pole double-throw analog switch 235 is connected in parallel at both ends of the fifth resistor 233. The second resistance adjustment device 23 is used to generate the comparison voltage required by the four comparators of the comparison output module 3, and the single-pole double-throw analog switch 235 is used to select and output. The power supply is a voltage of VCC5V, which is divided by the first resistor 211 and the second resistor 212 in the voltage divider 21 to obtain a 2V power supply, which is filtered by the first capacitor 213 and input to the positive electrode of the voltage follower 22. The voltage follower 22 outputs a 2V reference voltage, which is grounded by the third resistor 231, the fourth resistor 232, the fifth resistor 233 and the sixth resistor 234 in the second resistance adjustment device 23 to obtain reference voltages of 1V, 0.5V and 0.28V respectively. Among them, since the reference voltage required for the wheel speed sensors of Type 1 / 2 and Type 3 types when the subsequent comparator U2 detects the sensor open circuit or short circuit to ground fault is different, in order to use the same comparator to detect the sensor open circuit or short circuit to ground fault when using different types of wheel speed sensors, the comparison voltage of this comparator needs to be switched with the switching of the wheel speed sensor type. Therefore, we use a single-pole double-throw analog switch 235 to select between 0.28V and 0.5V reference voltages. SW-EN is a selection signal, which is the same as the enable signal of the first switch 133 described above. When SW-EN is low, a Type 1 / 2 wheel speed sensor is used, and a 0.5V reference voltage output is selected; when SW-EN is high, a Type 3 wheel speed sensor is used, and a 0.28V reference voltage output is selected.

[0036] like Figure 4As shown, the comparison output module 3 includes a first comparator 31, a second comparator 32, a third comparator 33 and a fourth comparator 34 connected in parallel, the positive electrodes of the first comparator 31, the second comparator 32, the third comparator 33 and the fourth comparator 34 are electrically connected to the external wheel speed signal input module 1, and the negative electrodes of the first comparator 31, the second comparator 32, the third comparator 33 and the fourth comparator 34 are electrically connected to the reference voltage generation module 2. The second comparator 32 and the third comparator 33 are connected through an XOR gate 39. The first comparator 31, the second comparator 32, the third comparator 33 and the fourth comparator 34 are each connected to a stabilizing device. The stabilizing device includes a pull-up resistor and a stabilizing capacitor, the pull-up resistor is connected to the power supply, and the stabilizing capacitor is connected to the ground wire. In this embodiment, the first stabilizing device 35, the second stabilizing device 36, the third stabilizing device 37 and the fourth stabilizing device 38 are connected to the first comparator 31, the second comparator 32, the third comparator 33 and the fourth comparator 34 respectively. The first stabilizing device 35 includes a ninth resistor 351 and a fourth capacitor 352, the second stabilizing device 36 includes a tenth resistor 361 and a fifth capacitor 362, the third stabilizing device 37 includes an eleventh resistor 371 and a sixth capacitor 372, and the fourth stabilizing device 38 includes a twelfth resistor 381 and a seventh capacitor 382. By comparing the wheel speed voltage signal with different reference voltages through the comparator, the output of the wheel speed signal and the diagnosis of the open circuit, short circuit to ground, short circuit to power supply and overcurrent of the wheel speed sensor signal can be performed. The positive electrodes of the first comparator 31, the second comparator 32, the third comparator 33 and the fourth comparator 34 are connected to the external wheel speed input voltage signal generated by the first resistance adjustment device 13, and the negative electrodes are connected to the four reference voltages respectively.

[0037] Among them, the first comparator 31 can diagnose whether the wheel speed signal is open or short-circuited to the ground, and the reference voltage of the negative electrode switches with the switching of the wheel speed sensor type. When a Type 1 / 2 wheel speed sensor is used, the reference voltage connected to the negative electrode is 0.5V. The pull-down resistor at this time is 100Ω, that is, when the current is lower than 5mA, the wheel speed signal is open or short-circuited to the ground. The first comparator 31 outputs a low level, and after the ninth resistor 351 is pulled up to VCC5V and the fourth capacitor 352 is filtered, the MCU collects and determines that the wheel speed signal is open or short-circuited to the ground at this time. A Type 3 wheel speed sensor is used, and the reference voltage connected to the negative electrode is 0.28V. The pull-down resistor at this time is 50Ω, that is, when the current is lower than 5.6mA, the wheel speed signal is open or short-circuited to the ground. The first comparator 31 outputs a low level, and after the ninth resistor 351 is pulled up to VCC5V and the fourth capacitor 352 is filtered, the MCU collects and determines that the wheel speed signal is open or short-circuited to the ground at this time. In both cases, the current threshold for judging whether the wheel speed signal is open or short-circuited to the ground is lower than the theoretical minimum value of the normal low current of the wheel speed sensor, so the risk of false alarm of open circuit or short circuit to the ground is low.

[0038] The second comparator 32 is used to output the additional information signal in the wheel speed signal of the Type 3 wheel speed sensor. According to the current size of the additional information signal, the reference voltage of the negative pole is connected to 0.5V. Because the speed pulse signal in the wheel speed information of the Type 3 wheel speed sensor will also be output as high in the second comparator 32, in order to separate the speed pulse signal from the additional information signal, only the additional information signal is output in this way. After the output signals of the second comparator 32 and the third comparator 33 are XORed by the XOR gate 39, the output signal only contains the additional information signal. After the output signal of the XOR gate 39 is pulled up to VCC5V by the tenth resistor 361 and filtered by the fifth capacitor 362, the MCU collects the voltage of the additional information signal at this time and analyzes it.

[0039] The third comparator 33 is used to output the speed pulse signal in the wheel speed information of the three types of wheel speed sensors. According to the current size of the speed pulse signal, the reference level of the negative electrode is connected to 1V. After the output speed pulse signal is pulled up to VCC5V by the eleventh resistor 371 and filtered by the sixth capacitor 372, the MCU collects the voltage of the speed pulse signal at this time and analyzes it.

[0040] The fourth comparator 34 can diagnose whether the wheel speed signal is short-circuited to the power supply or overcurrent, and the negative reference voltage is connected to 2V. That is, when the Type 1 or Type 2 wheel speed sensor is used, the current exceeds 20mA or when the Type 3 wheel speed sensor is used, the current exceeds 40mA, which means that the wheel speed signal is short-circuited to the power supply or overcurrent. The fourth comparator 34 outputs a high level, and after being pulled up to VCC5V by the twelfth resistor 381 and filtered by the seventh capacitor 382, ​​the MCU collects and determines that the wheel speed signal is short-circuited to the power supply or overcurrent at this time. Both of these thresholds are greater than the theoretical maximum value of the normal high current of each wheel speed sensor, so the risk of false alarm of short circuit to the power supply or overcurrent is low.

[0041] like Figure 5 and Figure 6 As shown, when the system is working normally, when a Type 1 or Type 2 wheel speed sensor is used, the MCU only analyzes the speed pulse signal output by the third comparator 33; when a Type 3 wheel speed sensor is used, the MCU analyzes the additional information signal output by the XOR gate 39 and the speed pulse signal output by the third comparator 33. When the MCU recognizes that the first comparator 31 outputs a low level, it is highly likely that the wheel speed signal is open or short-circuited to the ground; when the MCU recognizes that the fourth comparator 34 outputs a high level, it is highly likely that the wheel speed signal is short-circuited to the power supply or overcurrent and other abnormal working conditions occur.

Claims

1. A signal acquisition and processing system compatible with multiple automobile wheel speed sensors, characterized in that: It includes an external wheel speed signal input module, a reference voltage generation module and a comparison output module. The external wheel speed signal input module is electrically connected to the comparison output module, the reference voltage generation module is electrically connected to the comparison output module, the external wheel speed signal input module is used to connect to the wheel speed sensor to collect the wheel speed signal, the reference voltage generation module is used to generate a reference voltage, and the comparison output module is used to output a voltage.

2. The signal acquisition and processing system compatible with multiple automobile wheel speed sensors according to claim 1, characterized in that: The external wheel speed signal input module includes a TVS tube, a third capacitor and a first resistance adjustment device which are sequentially connected through a circuit, and the TVS tube, the third capacitor and the first resistance adjustment device are respectively connected to the ground wire.

3. The signal acquisition and processing system compatible with multiple automobile wheel speed sensors according to claim 2 is characterized in that: The first resistance adjustment device includes a seventh resistor and an eighth resistor connected in series, and a first switch is connected in parallel at both ends of the eighth resistor.

4. The signal acquisition and processing system compatible with multiple automobile wheel speed sensors according to claim 1, characterized in that: The reference voltage generating module comprises a voltage dividing device, a voltage follower and a second resistance adjusting device, wherein the voltage dividing device is electrically connected to the voltage follower, and the voltage follower is electrically connected to the second resistance adjusting device.

5. The signal acquisition and processing system compatible with multiple types of automobile wheel speed sensors according to claim 4, characterized in that: The voltage divider device includes a first resistor, a second resistor and a first capacitor, the first resistor is electrically connected to the second resistor, the first resistor is connected to a power supply, the second resistor is connected to a ground wire, a first capacitor is connected in parallel at both ends of the second resistor, and the first capacitor is electrically connected to the voltage follower.

6. The signal acquisition and processing system compatible with multiple types of automobile wheel speed sensors according to claim 4, characterized in that: The second resistance adjustment device includes a third resistor, a fourth resistor, a fifth resistor and a sixth resistor connected in sequence through a circuit, the sixth resistor is connected to the ground wire, and a single-pole double-throw analog switch is connected in parallel at both ends of the fifth resistor.

7. The signal acquisition and processing system compatible with multiple types of automobile wheel speed sensors according to claim 1, characterized in that: The comparison output module includes a first comparator, a second comparator, a third comparator and a fourth comparator connected in parallel, wherein the positive poles of the first comparator, the second comparator, the third comparator and the fourth comparator are electrically connected to the external wheel speed signal input module, and the negative poles of the first comparator, the second comparator, the third comparator and the fourth comparator are electrically connected to the reference voltage generation module.

8. The signal acquisition and processing system compatible with multiple types of automobile wheel speed sensors according to claim 7, characterized in that: The second comparator and the third comparator are connected via an XOR gate.

9. The signal acquisition and processing system compatible with multiple automobile wheel speed sensors according to claim 7 or 8, characterized in that: The first comparator, the second comparator, the third comparator and the fourth comparator are each connected to a stabilizing device.

10. The signal acquisition and processing system compatible with multiple types of automobile wheel speed sensors according to claim 9, characterized in that: The stabilizing device comprises a pull-up resistor and a stabilizing capacitor, wherein the pull-up resistor is connected to a power source, and the stabilizing capacitor is connected to a ground line.

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