A wheel angle fault detection device and method applied to a steering system of an unmanned container truck

Abstract

The application provides a wheel angle fault detection device and method applied to an unmanned truck steering system, the device comprising: a hydraulic controller, which is used for obtaining a theoretical turning angle of each wheel according to a front and rear axle turning angle instruction, and calculating an equivalent steering angle according to an inner wheel angle a and an outer wheel angle b; a turning angle sensor, which is arranged on a bogie of a vehicle axle and is used for detecting a wheel turning angle in real time and sending a detection signal; and a displacement sensor, which is arranged on a steering oil cylinder on both sides of the vehicle and is used for judging whether a normal side steering oil cylinder extension error s is out of standard, and when the normal side steering oil cylinder extension error s is not out of standard, judging that the wheel angle fault is a secondary fault. The technical scheme can cover various fault modes, accurately judge the fault severity, and implement corresponding control strategies according to different faults.

Description

Technical Field

[0001] This application relates to the field of unmanned truck technology, and in particular to a wheel angle fault detection device and method for unmanned truck steering systems. Background Technology

[0002] With the development of technology, unmanned trucks are widely used. However, due to their heavy loads, unmanned trucks typically employ more powerful hydraulic cylinders for steering. Therefore, each axle's bogie uses wheel angle sensors to detect wheel angles in real time, forming a closed-loop control system to achieve precise steering. When the wheel angle sensor system malfunctions, the vehicle steering system needs to accurately determine the severity of the fault before the upper control system can implement different control strategies such as normal driving, reduced speed, or stopping. Existing wheel angle sensor systems typically only monitor the presence or absence of a sensor signal. If a signal is present, it's considered normal; if no signal is present, a fault is identified, and a level three fault is issued, resulting in immediate vehicle closure. This monitoring method and judgment mechanism are too simplistic, failing to cover all fault types and reducing the redundancy of the steering system, allowing even minor faults to cause the vehicle to stop immediately. Summary of the Invention

[0003] In view of this, the present invention provides a wheel corner fault detection device and method for unmanned truck steering systems, in order to solve the technical problems that the existing monitoring methods and judgment mechanisms are too simple, cannot cover all fault modes, and reduce the redundancy of the steering system.

[0004] This invention provides a wheel angle fault detection device for an unmanned truck steering system. The device includes a hydraulic controller for acquiring the theoretical steering angle of each wheel based on the steering angle commands from the front and rear axles of the vehicle, and calculating the equivalent steering angle based on the inner wheel angle 'a' and the outer wheel angle 'b'. The steering angle sensor is installed on the bogie of the vehicle axle to detect the wheel angle in real time and send a detection signal. The displacement sensor is installed on the steering cylinders on both sides of the vehicle. When the steering angle detection signal is normal and the equivalent steering angle c reaches the target value of the steering angle command, it determines whether the difference δ between each wheel angle and the theoretical steering angle exceeds the standard. When the difference δ exceeds the standard, it determines whether the extension error s of the steering cylinders on both sides exceeds the standard. When the extension error s of the steering cylinders on one side exceeds the standard, the vehicle starts to turn. When the wheel angle on the normal side reaches the theoretical steering angle of the wheel on that side, the displacement sensor determines whether the extension error s of the steering cylinder on the normal side exceeds the standard. When the extension error s of the steering cylinder on the normal side does not exceed the standard, the wheel angle fault is determined to be a level two fault.

[0005] Furthermore, the method includes: Step 1, the hydraulic controller obtains the theoretical steering angle of each wheel according to the steering angle commands of the front and rear axles of the vehicle, and calculates the equivalent steering angle based on the inner wheel angle 'a' and the outer wheel angle 'b'. Step 2: The steering angle sensor detects the wheel steering angle in real time and sends a detection signal. Step 3: Determine if the detection signal is normal. If normal, proceed to Step 4. Step 4: The vehicle begins to steer. When the equivalent steering angle c reaches the target value of the steering angle command, the displacement sensor determines whether the difference δ between each wheel angle and the theoretical steering angle exceeds the standard. Step 5: When the difference δ exceeds the standard, the displacement sensor determines whether the extension / retraction error s of the steering cylinders on both sides exceeds the standard. Step 6: When the extension / retraction error s of the steering cylinders on one side exceeds the standard, the vehicle begins to steer. When the wheel angle on the normal side reaches the theoretical steering angle of that side wheel, the displacement sensor determines whether the extension / retraction error s of the steering cylinder on the normal side exceeds the standard. Step 7: When the extension / retraction error s of the steering cylinder on the normal side does not exceed the standard, the wheel angle fault is determined to be a level two fault.

[0006] Furthermore, the method also includes: Step 0, the autonomous driving software issues steering commands to the front and rear axles of the vehicle.

[0007] Furthermore, step 3 also includes: if it is not normal, proceed to step 6; Furthermore, step 7 also includes: when the normal side steering cylinder extension / retraction error s exceeds the standard, the wheel angle fault is determined to be a level three fault.

[0008] Furthermore, step 5 also includes: when the extension and retraction errors s of both steering cylinders exceed the standard, the wheel angle fault is determined to be a level three fault.

[0009] Furthermore, step 5 also includes: if the extension / retraction error s of the two steering cylinders exceeds the standard on one side, then proceed to step 6.

[0010] Furthermore, step 5 also includes: when the difference δ does not exceed the standard, it is determined that the steering system is fault-free and the vehicle is steering normally.

[0011] Furthermore, the handling strategy for the second-level fault is to reduce speed, and the handling strategy for the third-level fault is to stop.

[0012] This invention provides a wheel angle fault detection device and method for unmanned truck steering systems. This technical solution adds a displacement sensor to detect the extension and retraction of the steering cylinder and compares it with the theoretical extension and retraction to determine which side the fault occurs on. If the fault is on one side, steering can still proceed normally, and a secondary fault is issued. Only if the fault occurs on both sides is a tertiary fault issued. The technical solution provided by this invention mainly addresses the technical problem that existing monitoring methods and judgment mechanisms are too simplistic and cannot cover all fault types. Attached Figure Description

[0013] Figure 1 This invention provides a schematic diagram of a steering process control applied to an unmanned truck steering system; Figure 2This is a schematic diagram of the positional relationship of an angle sensor provided by the present invention; Figure 3 This is a schematic diagram of the positional relationship of a displacement sensor provided by the present invention; Figure 4 This is a schematic diagram of another wheel angle fault detection method for unmanned truck steering systems provided by the present invention; Figure 5 This is a schematic diagram of the wheel angle sensor mounting structure provided by the present invention. Detailed Implementation

[0014] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0015] Example 1: This invention provides a wheel angle fault detection device and method for use in the steering system of unmanned trucks. The device includes a hydraulic controller, a steering angle sensor, and a displacement sensor. Figure 2 , 3 As shown, the angle sensor is mounted on the bogie of the vehicle axle, and the displacement sensor is mounted on the steering cylinders on both sides of the vehicle. Figure 4 As shown, the operating steps of this device are as follows.

[0016] Step 1: The hydraulic controller obtains the theoretical steering angle of each wheel based on the steering angle commands from the front and rear axles of the vehicle, and calculates the equivalent steering angle based on the inner wheel angle 'a' and the outer wheel angle 'b'. ; Step 2: The steering angle sensor detects the wheel steering angle in real time and sends out a detection signal; Step 3: Determine if the detection signal is normal. If it is normal, proceed to step 4. Step 4: The vehicle begins to turn. When the equivalent steering angle c reaches the target value of the steering angle command, it is determined whether the difference δ between each wheel angle and the theoretical wheel angle exceeds the standard. Step 5: When the difference δ exceeds the standard, determine whether the extension and retraction error s of the steering cylinders on both sides exceeds the standard. If the extension and retraction error s of the steering cylinders on both sides exceeds the standard, then the wheel angle fault is determined to be a level three fault.

[0017] The technical solution provided by this invention adds a displacement sensor to detect the extension and retraction of the steering cylinder and compares it with the theoretical extension and retraction to determine the fault level. This allows the vehicle to take corresponding handling strategies based on the fault level, solving the technical problem that the existing monitoring methods and judgment mechanisms are too simple and cannot cover all fault types.

[0018] Example 2: This invention provides a wheel angle fault detection device and method for use in the steering system of unmanned trucks. The device includes a hydraulic controller, a steering angle sensor, and a displacement sensor. Figure 2 , 3 As shown, the angle sensor is mounted on the bogie of the vehicle axle, and the displacement sensor is mounted on the steering cylinders on both sides of the vehicle. Figure 1 As shown, the operating steps of this device are as follows.

[0019] Step 0: The autonomous driving software issues steering commands to the front and rear axles of the vehicle; The turning command includes the target turning angle for the front and rear axles of the vehicle.

[0020] Step 1: The hydraulic controller obtains the theoretical steering angle of each wheel based on the steering angle commands from the front and rear axles of the vehicle, and calculates the equivalent steering angle based on the inner wheel angle 'a' and the outer wheel angle 'b'. ; Unmanned container trucks typically come in two types: 2-axle and 4-axle, and are all-axle steering. For 4-axle vehicles, such as... Figure 2 As shown, autonomous driving simplifies the unmanned truck into a two-wheeled vehicle model, with its wheelbase being the distance from bridge #1 to bridge #4. When turning, the autonomous driving software issues the target turning angles of the front and rear axles to bridge #1 and bridge #4 respectively. Bridge #2 and bridge #3 are calculated using the target turning angles of bridge #1 and bridge #4 according to the Ackerman relation.

[0021] For a given bridge, if the left and right wheels of the axle, also known as the inner and outer wheels (the side closer to the steering center is the inner wheel), have steering angles of a and b respectively, then the equivalent steering angle of the bridge is: The linkage structure of the axle dictates that a and b can only have a one-to-one correspondence, and b increases as a increases, i.e., "monotonically increasing." Thus, c also has a one-to-one correspondence with a and b, and is also "monotonically increasing." Due to the limitations of the axle's steering structure, the range of the inner wheel angle 'a' is 0~40 degrees, and the range of the outer wheel angle 'b' is 0~32 degrees.

[0022] Step 2: The steering angle sensor detects the wheel steering angle in real time and sends out a detection signal; Step 3: Determine if the detection signal is normal. If it is normal, proceed to step 4. Step 4: The vehicle begins to turn. When the equivalent steering angle c reaches the target value of the steering angle command, it is determined whether the difference δ between each wheel angle and the theoretical wheel angle exceeds the standard. Step 5: When the difference δ exceeds the standard, determine whether the extension and retraction error s of the steering cylinders on both sides exceeds the standard. If the extension and retraction error s of the steering cylinders on both sides exceeds the standard, then the wheel angle fault is determined to be a level three fault.

[0023] Since the wheel angle sensor system comprises a connecting shaft, connecting shaft clamping screws, sensor bracket, bracket fixing screws, wheel angle sensor, and signal cable, a malfunction in any of these components can lead to steering failure. Therefore, when the wheel angle sensor system malfunctions, the steering system must accurately determine the severity of the malfunction so that the upper control system can implement different control strategies for the vehicle, such as normal driving, reduced speed, or stopping. The severity of the malfunction is categorized into three levels: Level 1, Level 2, and Level 3, with Level 3 being the most severe. Different handling strategies are implemented based on the severity. A Level 3 malfunction requires stopping the vehicle; a Level 1 malfunction allows for normal driving; and a Level 2 malfunction requires reduced speed.

[0024] The technical solution provided by this invention adds a displacement sensor to detect the extension and retraction of the steering cylinder and compares it with the theoretical extension and retraction to determine the fault level. This allows the vehicle to take corresponding handling strategies based on the fault level, solving the technical problem that the existing monitoring methods and judgment mechanisms are too simple and cannot cover all fault types.

[0025] Example 3: This invention provides a wheel angle fault detection device and method for use in the steering system of unmanned trucks. The device includes a hydraulic controller, a steering angle sensor, and a displacement sensor. Figure 2 , 3 As shown, the angle sensor is mounted on the bogie of the vehicle axle, and the displacement sensor is mounted on the steering cylinders on both sides of the vehicle. Figure 1 As shown, the operating steps of this device are as follows.

[0026] Step 1: The hydraulic controller obtains the theoretical steering angle of each wheel based on the steering angle commands from the front and rear axles of the vehicle, and calculates the equivalent steering angle based on the inner wheel angle 'a' and the outer wheel angle 'b'. ; Step 2: The steering angle sensor detects the wheel steering angle in real time and sends out a detection signal; Step 3: Determine if the detection signal is normal. If it is normal, proceed to step 4; otherwise, proceed to step 6. Step 4: The vehicle begins to turn. When the equivalent steering angle c reaches the target value of the steering angle command, the displacement sensor determines whether the difference δ between each wheel angle and the theoretical wheel angle exceeds the standard. Step 5: When the difference δ exceeds the standard, determine whether the extension and retraction error s of both steering cylinders exceeds the standard. If the extension and retraction error s of both steering cylinders exceeds the standard, the wheel angle fault is determined to be a level three fault. If the extension and retraction error s of one of the two steering cylinders exceeds the standard, proceed to step 6. If the difference δ does not exceed the standard, the steering system is determined to be fault-free and the vehicle can steer normally. Compared to existing technologies, this invention adds a displacement sensor, which, in addition to determining the detection signal emitted by the angle sensor, can also determine whether the difference δ between each wheel angle and the theoretical wheel angle exceeds the standard, and whether the extension / retraction error s of the steering cylinder exceeds the standard, thus making the judgment results more accurate. Figure 3 As can be seen, the displacement sensor is located on the steering cylinders on both sides of the vehicle. It can determine whether the extension and retraction error s of the steering cylinders on both sides exceeds the standard. Therefore, there are three situations: one is that both sides exceed the standard at the same time, that is, both sides are faulty; the second is that one side exceeds the standard, that is, the side that exceeds the standard is faulty; and the third is that neither side exceeds the standard, that is, there is no fault.

[0027] Since the displacement sensor can monitor the displacement value d of the inner wheel cylinder and the displacement value e of the outer wheel cylinder, and d and e have a one-to-one correspondence with the inner wheel angle a, the outer wheel angle b, and the equivalent steering angle c, as shown in Table 1:

[0028] Table 1. Correspondence between displacement sensor monitoring values ​​and inner wheel angle, outer wheel angle, and equivalent steering angle. As can be seen from the above, the detection method and judgment mechanism of the technical solution provided in this application are more reliable and have more basis than the existing technology, and therefore the judgment is more accurate.

[0029] Step 6: The vehicle begins to steer. When the wheel angle on the normal steering side reaches the theoretical turning angle of the wheel on that side, the displacement sensor determines whether the extension and retraction error s of the steering cylinder on the normal side exceeds the standard. If it exceeds the standard, proceed to step 7; otherwise, proceed to step 8. Step 7: When the normal side steering cylinder extension / retraction error s exceeds the standard, the wheel angle fault is judged to be a level three fault. Step 8: If the normal side steering cylinder extension / retraction error s does not exceed the standard, then the wheel angle fault is judged to be a level two fault.

[0030] As mentioned above, the angle sensor consists of multiple components, such as... Figure 5 As shown, a malfunction in any component can affect vehicle steering. The newly added displacement sensor determines the level of wheel angle malfunction by assessing multiple factors, including whether the detection signal from the steering angle sensor is normal, whether the difference δ between each wheel angle and the theoretical wheel angle exceeds the standard, and whether the steering cylinder extension / retraction error s exceeds the standard. This allows for the implementation of corresponding corrective measures. As shown in Tables 2 and 3, a comparison of the two tables clearly demonstrates that the technical solution provided in this application is more accurate than existing technologies, effectively preventing even minor malfunctions from causing the vehicle to stop directly, thereby improving vehicle operating efficiency.

[0031]

[0032] Table 2 Fault Level Determination Table for Existing Technologies Without Displacement Sensors

[0033] Table 3 Fault Level Determination Table for Technical Solutions Provided in This Application that Include Displacement Sensors The technical solution provided by this invention adds a displacement sensor to detect the extension and retraction of the steering cylinder and compares it with the theoretical extension and retraction to determine the fault level. This allows the vehicle to take corresponding handling strategies based on the fault level, solving the technical problem that the existing monitoring methods and judgment mechanisms are too simple and cannot cover all fault types.

[0034] In summary, this invention provides a wheel angle fault detection device and method for unmanned truck steering systems. This technical solution adds a displacement sensor to detect the extension and retraction of the steering cylinder and compares it with the theoretical extension and retraction to determine which side the fault occurs on. If the fault is on one side, steering can still proceed normally, and a secondary fault is issued. Only if the fault occurs on both sides is a tertiary fault issued. The technical solution provided by this invention mainly addresses the problem that existing technologies have overly simplistic monitoring methods and judgment mechanisms that cannot cover all fault types.

[0035] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A wheel angle fault detection device applied to the steering system of an unmanned truck, characterized in that, The device includes: The hydraulic controller is used to obtain the theoretical steering angle of each wheel based on the steering angle commands from the front and rear axles of the vehicle, and to calculate the equivalent steering angle based on the inner wheel angle 'a' and the outer wheel angle 'b'. ; Angle sensors are installed on the bogies of the vehicle axle to detect wheel angles in real time and send out detection signals. Displacement sensors are installed on the steering cylinders on both sides of the vehicle. When the steering angle detection signal is normal and the equivalent steering angle c reaches the target value of the steering angle command, the sensor determines whether the difference δ between each wheel angle and the theoretical steering angle exceeds the standard. When the difference δ exceeds the standard, the sensor determines whether the extension / retraction error s of the steering cylinders on both sides exceeds the standard. When the extension / retraction error s of the steering cylinders on one side exceeds the standard, the vehicle begins to steer. When the wheel angle on the normal side reaches the theoretical steering angle of the wheel on that side, the displacement sensor determines whether the extension / retraction error s of the steering cylinder on the normal side exceeds the standard. When the extension / retraction error s of the steering cylinder on the normal side does not exceed the standard, the wheel angle fault is determined to be a level two fault.

2. A method for detecting wheel angle faults in an unmanned truck steering system using the wheel angle fault detection device described in claim 1, characterized in that, The method includes: Step 1: The hydraulic controller obtains the theoretical steering angle of each wheel based on the steering angle commands from the front and rear axles of the vehicle, and calculates the equivalent steering angle based on the inner wheel angle 'a' and the outer wheel angle 'b'. ; Step 2: The steering angle sensor detects the wheel steering angle in real time and sends out a detection signal; Step 3: Determine if the detection signal is normal. If it is normal, proceed to step 4. Step 4: The vehicle begins to turn. When the equivalent steering angle c reaches the target value of the steering angle command, the displacement sensor determines whether the difference δ between each wheel angle and the theoretical steering angle exceeds the standard. Step 5: When the difference δ exceeds the standard, the displacement sensor determines whether the extension and retraction error s of the steering cylinders on both sides exceeds the standard. Step 6: When the extension / retraction error s of the steering cylinders on both sides exceeds the standard, the vehicle begins to steer. When the wheel angle on the normal side reaches the theoretical turning angle of the wheel on that side, the displacement sensor determines whether the extension / retraction error s of the steering cylinder on the normal side exceeds the standard. Step 7: If the normal side steering cylinder extension / retraction error s does not exceed the standard, then the wheel angle fault is judged to be a level two fault.

3. The wheel angle fault detection method applied to the steering system of an unmanned truck according to claim 2, characterized in that, The method further includes: Step 0: The autonomous driving software issues steering commands to the front and rear axles of the vehicle.

4. The wheel angle fault detection method applied to the steering system of an unmanned truck according to claim 2, characterized in that, Step 3 also includes: if it is not normal, proceed to step 6.

5. The wheel angle fault detection method applied to the steering system of an unmanned truck according to claim 4, characterized in that, Step 7 further includes: when the normal side steering cylinder extension / retraction error s exceeds the standard, the wheel angle fault is judged to be a level three fault.

6. The wheel angle fault detection method applied to the steering system of an unmanned truck according to claim 4, characterized in that, Step 5 further includes: if the extension and retraction errors s of both steering cylinders exceed the standard, the wheel angle fault is determined to be a level three fault.

7. The wheel angle fault detection method applied to the steering system of an unmanned truck according to claim 4, characterized in that, Step 5 further includes: if the extension / retraction error s of the two steering cylinders exceeds the standard on one side, then proceed to step 6.

8. The wheel angle fault detection method applied to the steering system of an unmanned truck according to claim 2, characterized in that, Step 5 further includes: when the difference δ does not exceed the standard, it is determined that the steering system is fault-free and the vehicle steers normally.

9. A wheel angle fault detection method for an unmanned truck steering system according to claim 2 or 6, characterized in that, The handling strategy for level 2 faults is to reduce speed, and the handling strategy for level 3 faults is to stop.

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