A method and system for measuring wheel camber angle and toe angle

Abstract

The present invention discloses a method and system for measuring wheel camber angle and toe angle, including arranging a plurality of signal transmitters on each steering knuckle connected to the wheel, and connecting the signal transmitters to an in-vehicle computer; arranging signal receivers on the vehicle body, connecting the signal receivers to the in-vehicle computer, and establishing a three-dimensional coordinate system of the vehicle body; during the driving process of the vehicle, the signal receivers receive the signals emitted by the signal transmitters, calculate the coordinate values of each signal receiver in the vehicle body coordinate system, and obtain the wheel camber angle and toe angle; comparing the real-time values of the obtained wheel camber angle and toe angle with a preset range to monitor the running state of the vehicle in real time; the present invention can monitor the parameter changes of the wheel camber angle and toe angle of the vehicle under different driving conditions in real time, so as to timely maintain and repair the tires.

Description

Technical Field

[0001] The present invention relates to the technical field of vehicle measurement, and particularly relates to a method and system for measuring wheel camber angle and toe angle. Background Art

[0002] When designing a vehicle, the installation of the four wheels has a certain relative positional relationship to ensure the driving and handling stability of the vehicle. Generally, the tires on the left and right sides of the vehicle are set in an outward V shape; vehicle four-wheel alignment is based on the four-wheel parameters of the vehicle. The four-wheel parameters include caster angle, kingpin inclination angle, wheel camber angle, and wheel toe angle. The reasonable selection of four-wheel alignment parameters plays an important role in reducing tire wear, improving the overall vehicle direction control, and reducing fuel consumption. Currently, wheel alignment generally mainly detects the wheel camber angle and wheel toe angle.

[0003] The wheel camber angle refers to the angle between the vertical geometric centerline of the tire and the ground vertical line when looking at the tire from the front of the vehicle while standing at the hood of the vehicle in front of the vehicle, which is called the camber angle.

[0004] The toe angle refers to the angle between the horizontal centerline of the tire and the longitudinal axis along the vehicle length direction when looking down from directly above the vehicle, which is called the toe angle.

[0005] In the existing four-wheel alignment measurement technology, three-dimensional imaging technology is mainly used to measure four-wheel alignment parameters. The measurement system includes a camera, a computer, a wheel fixture, a reflector, and four-wheel alignment measurement software; the reflector is installed on the vehicle wheel through the wheel fixture, the image of the reflector is captured by the camera, and then the image is transmitted to the computer to obtain the spatial angle information of the positions of the four wheels. Finally, based on the analysis and calculation of the measurement software, the four-wheel alignment parameter data of the vehicle is obtained; in the prior art, the reflector needs to be installed on the vehicle before each measurement, and the camera and vehicle state need to be calibrated before measurement can be carried out; at the same time, the reflector needs to be removed after measurement, and it needs to be reinstalled during the next measurement. The operation process of each measurement is complex and the detection speed is slow; and the existing measurement method is based on the principle of image recognition after taking pictures, so the existing method can only realize the measurement of four-wheel alignment parameters under the static condition of the vehicle, and cannot dynamically and real-time measure and monitor the four-wheel alignment parameters of the vehicle. Summary of the Invention

[0006] The object of the present invention is to provide a detection method and system for measuring wheel camber angle and toe angle.

[0007] To achieve the above object, the technical solution of the present invention is as follows:

[0008] A method for measuring wheel camber angle and toe angle, comprising the following steps:

[0009] A plurality of signal transmitters are arranged on each steering knuckle connected to the wheel, and the signal transmitters are connected to the vehicle-mounted computer;

[0010] A signal receiver is arranged on the vehicle body, and the signal receiver is connected to the vehicle-mounted computer to establish a three-dimensional coordinate system of the vehicle body;

[0011] During the driving of the vehicle, the signal receiver receives the signals emitted by the signal transmitters, calculates the coordinate values of each signal receiver in the vehicle body coordinate system, and obtains the wheel camber angle and the toe angle;

[0012] Compare the real-time values of the obtained wheel camber angle and toe angle with the preset range to monitor the running state of the vehicle in real time.

[0013] Furthermore, three signal transmitters are arranged on each steering knuckle, namely a first signal transmitter, a second signal transmitter, and a third signal transmitter.

[0014] Furthermore, the three signal transmitters are located on the circumference of the same circular plane, and the wheel rotates around the rotation axis, and the center of the circular plane is on the rotation axis.

[0015] Furthermore, the wheel camber angle α(t)= ,

[0016] where B 车轮 , C 车轮 are intermediate parameters, and their calculation formulas are:

[0017] C 车轮 =(x02 - x01)*(y03 - y01)-(x03 - x01)*(y02 - y01)

[0018] B 车轮 =(z02 - z01)*(x03 - x01)-(z03 - z01)*(x02 - x01),,

[0019] where x01, y01, z01 are the coordinate values of the first signal transmitter; x02, y02, z02 are the coordinate values of the second signal transmitter; x03, y03, z03 are the coordinate values of the third signal transmitter.

[0020] Furthermore, the wheel toe angle β(t)= ,

[0021] where A 车轮 is an intermediate parameter, and its calculation formula is:

[0022] A 车轮=(y02- y01)*(z03- z01)-(y03- y01)*(z02- z01).

[0023] Furthermore, the coordinate value of each signal receiver in the vehicle body coordinate system is calculated based on the coordinate value of the signal receiver and the distance between the signal receiver and the signal transmitter.

[0024] Furthermore, the signal transmitter is an electromagnetic wave signal transmitter, and the distance between the signal receiver and the signal transmitter is obtained by multiplying the propagation speed of the electromagnetic wave in the air by the time difference between signal transmission and signal reception.

[0025] A system for measuring the camber angle and toe angle of a wheel comprises a plurality of signal transmitters, a plurality of signal receivers and an on-board computer, wherein the plurality of signal transmitters are located on the steering knuckle of the vehicle; the plurality of signal transmitters are located on the circumference of the same circular plane, the center of the circular plane is located on the rotation axis of the wheel, the plurality of signal receivers are located on the vehicle body, the plurality of signal transmitters and the plurality of signal receivers are connected to the on-board computer, and the signal receivers are used to receive signals sent by the signal transmitters.

[0026] Furthermore, the multiple signal receivers are located at locations other than the wheels of the vehicle body.

[0027] Furthermore, each steering knuckle is provided with three threaded holes, and the circular plane defined by the three threaded holes is perpendicular to the rotation axis of the wheel, and the signal transmitter is fixed to the steering knuckle by bolts and the threaded holes.

[0028] The beneficial effects of the present invention are:

[0029] 1. All measuring devices and systems of the present invention are fixedly installed on the vehicle, without any external instruments or equipment access. Compared with the prior art, there is no need to repeatedly install and disassemble the measuring devices.

[0030] 2. The present invention can monitor in real time the parameter changes of the camber angle and toe angle of the vehicle's wheels under different driving conditions; since the signal output by the signal transmitter is dynamic and real-time, the measurement and monitoring of the vehicle's four-wheel alignment information by the measurement method of the present invention is also dynamic and real-time; the values ​​of the measured camber angle, toe angle, and the dynamic changes of the inner and outer point coordinates of the wheel over time are recorded in the on-board computer and displayed on the display, thereby realizing real-time monitoring and recording of the wheel running status. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is a structural diagram of the wheel rim parts of the wheel of the present invention.

[0032] Figure 2It is a layout diagram of signal transmitters.

[0033] Figure 3 Layout diagram of signal receivers at the vehicle body end.

[0034] Figure 4 It is a schematic diagram of obtaining the coordinates of the transmitter through the coordinates of the signal receiver in the present invention.

[0035] In the figure: wheel 1; knuckle 2; hub 3; bearing 4; rotation axis 5; first signal transmitter 6; second signal transmitter 7; third signal transmitter 8; signal receiver 9. Specific implementation manner

[0036] In order to make the purpose, technical solutions and advantages of the invention clearer, the present invention will be further described below with reference to the accompanying drawings.

[0037] The four-wheel alignment measurement system and method of the present invention can be used for four-wheel vehicles with MacPherson, torsion beam, and multi-link suspension forms, including sedans, SUVs, etc. In this embodiment, a front MacPherson suspension with a knuckle is used for illustration:

[0038] A method for measuring wheel camber and toe angle includes the following steps:

[0039] Step 1: Arrange a plurality of signal transmitters on the knuckle 2 connected to the wheel 1;

[0040] As Figure 1 and Figure 2 shown, three threaded holes are provided on each knuckle 2. The wheel rotates around the rotation axis 5. When machining the threaded holes, it is necessary to ensure that the circular plane determined by the three threaded holes is perpendicular to the rotation axis 5 of the wheel. The signal transmitter is fixed to the knuckle through bolts and the threaded holes;

[0041] Arrange three signal transmitters on each knuckle 2, namely the first signal transmitter 6, the second signal transmitter 7, and the third signal transmitter 8; a total of twelve signal transmitters for four wheels. The signal transmitters are electrically connected to the vehicle-mounted computer, and the signal transmitters can be electromagnetic wave signal transmitters;

[0042] The three signal transmitters on each knuckle determine a circular plane, that is, the three signal transmitters on each knuckle are on the circumference of the same circle. The center of the circle coincides with the center of the outer side of the wheel, and the center of the circle is on the rotation axis 5; the center and axis of the circular plane determined by the three signal transmitters on each knuckle are the same as the center and axis of the outer side of the wheel.

[0043] Step 2: Arrange signal receivers on the vehicle body. The signal receivers are connected to the vehicle-mounted computer to complete the establishment of the vehicle body three-dimensional coordinate system;

[0044] As Figure 3 shown, three signal receivers 9 are arranged at the body end of the vehicle. The three signal receivers can be arranged inside the vehicle body or at positions outside the vehicle body except for the vehicle tires;

[0045] The first signal transmitter 6, the second signal transmitter 7, the third signal transmitter 8 and the three signal receivers 9 are all connected to the vehicle-mounted computer. The signal receivers receive the electromagnetic wave signals emitted by the signal transmitters, and the vehicle-mounted computer calibrates the signal transmitters and the signal receivers so that each signal transmitter has a corresponding signal receiver;

[0046] Regarding the establishment of the vehicle body three-dimensional coordinate system, any point on the vehicle body is used as the origin, and the vehicle body XYZ three-dimensional coordinate system is established through a three-coordinate measuring device and stored on the vehicle-mounted computer. After the vehicle body three-dimensional coordinate system is established, the coordinate values of each point on the vehicle body are known, so the coordinates of the three signal receivers located on the vehicle body are known.

[0047] Step three: During the driving of the vehicle, the signal receivers receive the signals emitted by the signal transmitters, calculate the coordinate values of two points on the wheel rotation axis 5 in the vehicle body coordinate system, and obtain the wheel camber angle and the toe angle;

[0048] During the driving of the vehicle, in the vehicle body coordinate system, any point on the vehicle body is used as the origin, so the coordinate values of the three signal receivers on the vehicle body are unchanged relative to the origin.

[0049] When the road on which the vehicle is driving is rough, during the process of the vehicle passing through a pothole or a bump, the wheels will bounce up and down, so the coordinate values of any point on the wheel rotation axis 5 will change continuously during the driving of the vehicle; the steering knuckle 2 is fixedly installed with the wheel, so the coordinate values of the three signal transmitters located on each steering knuckle 2 will also change continuously during the driving of the vehicle.

[0050] In this embodiment, the signal transmitter is an electromagnetic wave signal transmitter. The timer on the vehicle-mounted computer calculates the time difference between the signal received by the signal receiver and the signal emitted by the signal transmitter. The time difference multiplied by the propagation speed of the electromagnetic wave in the air is the distances a, b, and c between the three signal transmitters and their corresponding three signal receivers respectively.

[0051] Let the coordinates of the three signal transmitters on the steering knuckle 2 in the vehicle body three-dimensional coordinate system be: the first point: x01(t), y01(t), z01(t), the second point: x02(t), y02(t), z02(t), the third point: x03(t), y03(t), z03(t), where t represents the coordinate value of a certain point at time t.

[0052] After the three - dimensional coordinate system of the vehicle body is established, the coordinate values of the three signal receivers are known. Combining the coordinate values of the three signal receivers with the distances a, b, and c between the three signal transmitters and the corresponding three signal receivers respectively, the in - vehicle computer calculates the coordinate values of the three signal transmitters. Figure 4 It is the schematic diagram for obtaining the coordinates of the signal transmitter through the coordinates of the signal receiver and the distance between the signal receiver and the signal transmitter.

[0053] The wheel 1 is connected to the steering knuckle 2 through the wheel hub 3 and the bearing 4, and the wheel rotates around the rotation axis 5; during the continuous rotation of the wheel, the rotation axis 5 and the steering knuckle 2 always maintain a constant relative position relationship. Therefore, by the positions of the three signal transmitters on the steering knuckle, combined with the wheel size stored in the in - vehicle computer and the distance value from the signal transmitter to the center of the wheel, the coordinate values of the center point of the inner side surface of the wheel and the center point of the outer side surface of the wheel on the rotation axis 5 can be obtained.

[0054] Let the coordinate of the center point of the inner side surface of the wheel be x1(t), y1(t), z1(t), and the coordinate of the center point of the outer side surface of the wheel be x2(t), y2(t), z2(t), where t represents the coordinate value of a certain point at time t; the line connecting the center point of the inner side surface of the wheel and the center point of the outer side surface of the wheel can form the wheel rotation axis 5.

[0055] Based on the coordinate values of the three signal transmitters on the steering knuckle, and at the same time combining the distance value from the signal transmitter to the center of the wheel, the coordinate value of the center of one side of the wheel can be obtained. Combining with the wheel size, such as the distance value from the center point of the inner side surface of the wheel to the center point of the outer side surface of the wheel, the coordinate value of the center of the other side of the wheel can be obtained, that is, x1(t), y1(t), z1(t), x2(t), y2(t), z2(t) are obtained, where t represents the coordinate value of a certain point at time t;.

[0056] Two points determine a straight line. Based on the coordinate values of the center point of the inner side surface of the wheel and the center point of the outer side surface of the wheel, the spatial vector of the wheel rotation axis is obtained;

[0057] The present invention calculates the coordinates of the three signal transmitter points on the steering knuckle 2, the coordinate values of the center point of the inner side surface of the wheel and the center point of the outer side surface of the wheel, and the process is as follows:

[0058] The three signal generators on the steering knuckle 2 can determine a circular plane, and the normal vector of this circular plane is parallel to the wheel rotation center.

[0059] Therefore, the direction of the wheel rotation axis 5 can be indirectly obtained through the direction of the normal vector of the circular plane. According to the angles between the normal vector and the XY plane and the YZ plane in the vehicle body coordinate system, the camber angle and the toe - in angle of the vehicle can be obtained.

[0060] Three signal transmitters located on a knuckle 2 determine a circular plane. According to the principle of the spatial geometric coordinate system, the formula for the normal vector of the plane determined by three points is:

[0061]

[0062] where A, B, and C are intermediate parameters, and their calculation formulas are:

[0063]

[0064] The rotation axis 5 is perpendicular to the circular plane determined by the three signal transmitters; based on the fact that the direction vector of the wheel rotation axis is the same as the normal vector direction of the circular plane determined by the three signal transmitters, the wheel rotation axis vector can be obtained as:

[0065] , where:

[0066]

[0067] i, j, and k are unit vectors in the same direction as the x-axis, y-axis, and z-axis. A unit vector refers to a vector with a modulus equal to 1. A 车轮 、B 车轮 、C 车轮 are intermediate parameters.

[0068] Furthermore, based on the spatial vector angle, the wheel camber angle and toe angle can be obtained through conversion;

[0069] where the angle between the wheel rotation axis vector and the XY plane in the vehicle body coordinate system is equal to the wheel camber angle, denoted as α(t); the angle between the wheel rotation axis vector and the YZ plane in the vehicle body coordinate system is equal to the wheel toe angle, denoted as β(t).

[0070] The conversion formulas are:

[0071] Wheel camber angle α(t)= ,

[0072] Wheel toe angle β(t)=

[0073] Step 4: Compare the real-time values of the obtained wheel camber angle and toe angle with the preset range to monitor the vehicle running state in real time;

[0074] Since the signals output by the signal transmitter are dynamic and real-time, the measurement and monitoring of the four-wheel alignment information of the vehicle by the measurement method of the present invention are also dynamic and real-time; the transmission frequency of the signal transmitter can also be set, such as transmitting a signal every 5 seconds or every 10 seconds; the values of the camber angle, toe angle, and the coordinates of the inner and outer points of the wheel that change dynamically over time are recorded in the vehicle computer and displayed through a display to achieve the monitoring and recording of the running state of the wheel; the vehicle computer stores the preset qualified ranges of the camber angle and toe angle. If the measured camber angle or toe angle is not within the preset qualified range, the vehicle tires should be maintained and repaired. The present invention can also be connected to a four-wheel alignment parameter out-of-tolerance warning system to remind the driver to perform maintenance on the vehicle.

[0075] A system for measuring the camber angle and toe angle of a wheel, comprising a plurality of signal transmitters, a plurality of signal receivers and a vehicle computer. The plurality of signal transmitters are located on the steering knuckle 2 of the vehicle; in this embodiment, three signal transmitters are arranged on each steering knuckle 2, namely a first signal transmitter 6, a second signal transmitter 7, and a third signal transmitter 8. The three signal transmitters are located on the circumference of the same circular plane, and the circular plane is concentric with the outer side surface of the wheel. The plurality of signal receivers are located at positions on the vehicle body other than the wheels; the plurality of signal transmitters and the plurality of signal receivers are both connected to the vehicle computer.

[0076] Finally, it should be noted that the content not described in detail in this specification belongs to the prior art well-known to those skilled in the art. The above are only the preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements on some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention shall be included in the protection scope of the present invention.

[0077] In the description of the present invention, it should be understood that the orientation or positional relationship indicated by the terms "inner", "outer", "upper", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present invention.

Claims

1. A method for measuring wheel camber angle and toe angle, characterized in that It includes the following steps: Arrange a plurality of signal transmitters on each steering knuckle (2) connected to the wheel (1), and arrange signal receivers (9) on the vehicle body. The signal transmitters and the signal receivers (9) are both connected to the in-vehicle computer; Establish a three-dimensional coordinate system of the vehicle body; During the driving of the vehicle, the signal receivers receive the signals emitted by the signal transmitters, calculate the coordinate values of each signal receiver in the vehicle body coordinate system, and obtain the wheel camber angle and the toe angle; The camber angle α(t) = , Among them, B 车轮 , C 车轮 The calculation formula is: C 车轮 = (x02 - x01) * (y03 - y01) - (x03 - x01) * (y02 - y01) B 车轮 = (z02 - z01) * (x03 - x01) - (z03 - z01) * (x02 - x01), Where x01, y01, and z01 are the coordinate values of the first signal transmitter (6); x02, y02, and z02 are the coordinate values of the second signal transmitter (7); x03, y03, and z03 are the coordinate values of the third signal transmitter (8); Compare the real-time values of the obtained wheel camber angle and toe angle with the preset range to monitor the running state of the vehicle in real time.

2. The method for measuring the camber angle and toe angle of a wheel according to claim 1, characterized in that: Three signal transmitters are arranged on each steering knuckle (2), namely the first signal transmitter (6), the second signal transmitter (7), and the third signal transmitter (8).

3. A method for measuring the camber angle and toe angle of a wheel according to claim 2, characterized in that: The three signal transmitters are located on the circumference of the same circular plane. The wheel rotates around the rotation axis (5), and the center of the circular plane is on the rotation axis (5).

4. A method for measuring wheel camber angle and toe angle as claimed in claim 1, characterized in that: The described front wheel toe angle β(t) = , Among them, A 车轮 The calculation formula is: A 车轮 = (y02 - y01) * (z03 - z01) - (y03 - y01) * (z02 - z01).

5. The method for measuring the camber angle and toe angle of a wheel according to claim 1, characterized in that: The coordinate value of each signal receiver in the vehicle body coordinate system is calculated based on the coordinate value of the signal receiver and the distance between the signal receiver and the signal transmitter.

6. The method for measuring the camber angle and toe angle of a wheel according to claim 1, wherein: The signal transmitter is an electromagnetic wave signal transmitter, and the distance between the signal receiver and the signal transmitter is obtained by multiplying the propagation speed of the electromagnetic wave in the air by the time difference between signal transmission and signal reception.

7. A measurement system for implementing the method for measuring the camber angle and toe angle of a wheel according to any one of claims 1-6, characterized in that: The measurement system includes a plurality of signal transmitters, a plurality of signal receivers (9) and an in-vehicle computer. The plurality of signal transmitters are located on the steering knuckles (2) of the vehicle; the plurality of signal transmitters are located on the circumference of the same circular plane, and the center of the circular plane is located on the wheel rotation axis (5). The plurality of signal receivers are located on the vehicle body, and the plurality of signal transmitters and the plurality of signal receivers are both connected to the in-vehicle computer. The signal receivers (9) are used to receive the signals emitted by the signal transmitters.

8. The measurement system according to claim 7, wherein: The plurality of signal receivers are located at parts of the vehicle body other than the wheels.

9. The measurement system according to claim 7, characterized in that: Three threaded holes are provided on each steering knuckle (2). The circular plane determined by the three threaded holes is perpendicular to the rotation axis (5) of the wheel, and the signal transmitter is fixed to the steering knuckle (2) through bolts and the threaded holes.

Images