A zero return method for incremental encoder steering wheel

Abstract

The invention discloses a zero return method suitable for an incremental encoder steering wheel, wherein a zero position switch is arranged on a steering wheel mounting plate, rotated with the steering wheel, and a fixed zero return hole is arranged on the slewing bearing of the steering wheel; after the steering wheel is powered on, the steering motor starts to work, and returns to the zero point by aligning the zero position switch with the zero return hole; when the zero position switch passes through the zero return hole, four edge values ​​are obtained, and the average of the four values ​​is used as the zero return pulse value of the steering wheel. The invention effectively avoids the errors caused by the gap of the transmission chain of the steering wheel steering mechanism and the delay of the photoelectric sensor signal, and improves the zero return repeatability accuracy of the steering wheel.

Description

Technical Field

[0001] The invention relates to the technical field of incremental encoders, and in particular to a zero return method suitable for a steering wheel of an incremental encoder. Background Art

[0002] At present, incremental encoders have been widely used in the fields of motion control and electrical transmission. They convert displacement signals into periodic electrical signals, and then convert electrical signals into pulse values ​​to represent the displacement size. Incremental encoders have the advantages of high precision, simple decoding, durability, and strong anti-interference. However, the incremental encoder needs to calculate the displacement data of the moving body based on the zero point. When the system is powered off and restarted, the zero point is lost. The moving body needs to return to the zero position and clear the current measurement data (or as compensation) to ensure that the subsequent displacement is correct. This process is called "return to zero".

[0003] At present, there are two commonly used methods for returning to zero in the steering wheel system. The first is the "elastic deformation method", in which an elastic mechanism is installed on the steering wheel to restore the zero position through the deformation of the elastic mechanism; the second is the "hard limit return to zero method", in which the steering wheel rotates forward after power is turned on until it is blocked at the hard limit of the steering wheel, and then the steering wheel rotates in the opposite direction according to the given pulse value to return to the zero position.

[0004] After repeated use of the "elastic deformation method", the performance of the elastic mechanism changes, resulting in a decrease in the repeatability of the steering wheel returning to zero, affecting the angle control effect of the steering wheel; and the disadvantage of the "hard limit return to zero method" is that after repeated impacts on the hard limit, the mechanical structure of the steering wheel will be deformed or loosened, resulting in a decrease in the repeatability of the steering wheel returning to zero. Summary of the invention

[0005] In the above background, an object of the present invention is to provide a zero return method applicable to an incremental encoder steering wheel, which meets the high-precision zero return requirement of the steering wheel.

[0006] The present invention achieves the above object through the following technical solutions:

[0007] A zero return method suitable for an incremental encoder steering wheel, wherein a zero position switch is arranged on a steering wheel mounting plate, rotated with the steering wheel, and a fixed zero return hole is arranged on a slewing bearing of the steering wheel; after the steering wheel is powered on, a steering motor starts to work and returns to the zero point by aligning the zero position switch with the zero return hole.

[0008] Furthermore, when the zero position switch passes through the zero return hole, four edge values ​​are obtained, and the average of the four values ​​is used as the zero return pulse value of the steering wheel.

[0009] Furthermore, the rotation angle of the zero position switch is limited within the positive and negative limit range. The positive limit position indicates the position of the zero position switch when the steering wheel rotates forward (counterclockwise is the positive direction) and hits the positive hard limit. The reverse limit position indicates the position of the zero position switch when the steering wheel rotates reversely (clockwise is the reverse direction) and hits the reverse hard limit.

[0010] Furthermore, the initial position of the zero position switch can be divided into three areas, namely, the zero position switch is located on the positive side of the return to zero hole, which is set as area A; the second place is when the zero position switch is located inside the return to zero hole, which is area B; the third place is located on the reverse side of the zero position, which is area C.

[0011] Furthermore, if the initial position of the zero position switch is located in area A, the steering wheel rotates counterclockwise (forward) after power-on, and the zero position switch reaches the positive limit position. Thereafter, the steering wheel rotates clockwise (reverse), and when passing through the zero return hole, two level changes are generated, and the edge pulse values ​​at the corresponding moments of the falling edge and the rising edge are measured, which are the reverse edge value and the reverse edge value; after running for a distance, the steering wheel rotates counterclockwise (forward) again, passes through the zero return hole, and the positive edge value and the positive edge value are obtained, and the average of the four values ​​is obtained, which is used as the zero return pulse value of the steering wheel.

[0012] Furthermore, if the initial position of the zero position switch is located in area B, the steering wheel rotates counterclockwise (forward) after power-on, and a level change is detected when the zero position switch leaves the zero return hole. After running for a certain distance, the steering wheel rotates clockwise (reverse) and when passing through the zero return hole again, a reverse entry edge value and a reverse exit edge value are obtained; thereafter, the steering wheel rotates counterclockwise (forward) and passes through the zero return hole to obtain a positive entry edge value and a positive exit edge value, and the average of the four values ​​is obtained, which is used as the zero return pulse value of the steering wheel.

[0013] Furthermore, if the initial position of the zero position switch is located in area C, the steering wheel rotates counterclockwise (forward) after power is turned on, and when the zero position switch passes through the zero return hole for the first time, a positive entry edge value and a positive exit edge value are obtained; thereafter, the steering wheel rotates clockwise (reverse) and passes through the zero return hole to obtain a reverse entry edge value and a reverse exit edge value, and the average value of the four values ​​is obtained, which is used as the zero return pulse value of the steering wheel.

[0014] Compared with the prior art, the beneficial effects of the present invention are as follows: the present invention arranges the zero position switch on the steering wheel mounting plate, and arranges a fixed zero return hole on the slewing bearing of the steering wheel; after the steering wheel is powered on, it returns to the zero point by aligning the zero position switch with the zero return hole, effectively avoiding the errors caused by the gap in the transmission chain of the steering wheel steering mechanism and the signal delay of the photoelectric sensor, and improving the zero return repeatability accuracy of the steering wheel. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic diagram of the steering position of the steering wheel of the present invention.

[0016] Figure 2 It is a schematic diagram of the four-point zero return of the steering wheel of the present invention. DETAILED DESCRIPTION

[0017] The technical solution of the present invention is further described in detail below in conjunction with the accompanying drawings:

[0018] The present invention provides Figure 1 and Figure 2 A zero return method suitable for an incremental encoder steering wheel is shown. A zero position switch 104 is provided on the mounting plate of the steering wheel, and a zero return hole 102 is provided on the slewing bearing. After the steering wheel is powered on, the steering motor starts to work and automatically finds the zero position by aligning the zero position switch 104 with the zero return hole 102.

[0019] like Figure 1 As shown, the rotation angle of the zero position switch 104 is limited to the range of the positive limit position 101 and the reverse limit position 103, and the area is divided according to the zero return hole 102 and the positive and reverse limit positions 101 and 103. The area from the right side of the zero return hole 102 to the positive limit position 101 is area A, the inside of the zero return hole 102 is area B, and the area from the left side of the zero return hole 102 to the reverse limit position 103 is area C.

[0020] Take the zero return process of area A as an example. Figure 1 and Figure 2 As shown, after the steering wheel is powered on, it rotates counterclockwise (forward), and the zero switch 104 reaches the forward limit position 101. Then the steering wheel rotates clockwise (reverse), and when the zero switch 104 passes through the zero return hole 102 for the first time, two level changes occur, such as Figure 2 As shown, the edge pulse values ​​at the corresponding moments of the falling edge and the rising edge are measured, which are the reverse edge value 201 and the reverse edge value 202; after running for a distance, the steering wheel rotates counterclockwise (forward) again, passes through the zero return hole 102 for the second time, and obtains the positive edge value 203 and the positive edge value 204. The average value of the four edge values ​​is obtained and used as the zero return pulse value of the steering wheel.

[0021] The above description is only a preferred example of the present invention, and does not limit the implementation mode and protection scope of the present invention. Any simple modification and equivalent changes made to the above embodiments based on the technical essence of the present invention fall within the protection scope of the present invention.

Claims

1. A zero return method for an incremental encoder steering wheel, characterized in that: A zero position switch (104) is arranged on the steering wheel mounting plate, and the zero position switch (104) rotates with the steering wheel. A fixed zero return hole (102) is arranged on the slewing bearing of the steering wheel. After the steering wheel is powered on, the steering motor starts to work and returns to the zero point by aligning the zero position switch (104) with the zero return hole (102); When the zero position switch (104) passes through the zero return hole (102), four edge values ​​are obtained, and the average of the four edge values ​​is used as the zero return pulse value of the steering wheel; The rotation angle of the zero position switch (104) is limited within a positive and negative limit range, the positive limit position (101) indicates the position of the zero position switch (104) when the steering wheel rotates forward to the positive hard limit, and the negative limit position (103) indicates the position of the zero position switch (104) when the steering wheel rotates reversely to the reverse hard limit, wherein the counterclockwise direction is the positive direction and the clockwise direction is the negative direction; The initial position of the zero position switch (104) is divided into three areas: A, B, and C. The range from the zero return hole (102) to the positive limit position (101) is set as area A; the inside of the zero return hole (102) is area B; and the range from the zero return hole (102) to the reverse limit position (103) is area C; If the initial position of the zero position switch (104) is located in area A, the steering wheel rotates counterclockwise after power is turned on, and the zero position switch (104) reaches the positive limit position (101). Then, the steering wheel rotates clockwise, and when it passes through the zero return hole (102) for the first time, two level changes are generated, and the edge pulse values ​​at the corresponding moments of the falling edge and the rising edge are measured, which are the reverse edge value (201) and the reverse edge value (202). After running for a certain distance, the steering wheel rotates counterclockwise again and passes through the zero return hole (102), and the positive edge value (203) and the positive edge value (204) are obtained. The average value of the four values ​​is obtained and used as the zero return pulse value of the steering wheel.

2. A zero return method for an incremental encoder steering wheel according to claim 1, characterized in that: If the initial position of the zero position switch (104) is located in area B, the steering wheel rotates counterclockwise after being powered on, and a level change is detected when the zero position switch (104) leaves the zero return hole (102). After running for a certain distance, the steering wheel rotates clockwise, and when passing through the zero return hole (102) again, a reverse entry edge value (201) and a reverse exit edge value (202) are obtained; then the steering wheel rotates counterclockwise, passes through the zero return hole, and obtains a positive entry edge value (203) and a positive exit edge value (204). The average value of the four values ​​is obtained and used as the zero return pulse value of the steering wheel.

3. A zero return method for an incremental encoder steering wheel according to claim 1, characterized in that: If the initial position of the zero position switch (104) is located in area C, the steering wheel rotates counterclockwise after power is turned on, and when the zero position switch (104) passes through the zero return hole (102) for the first time, a positive entry edge value (203) and a positive exit edge value (204) are obtained; then, the steering wheel rotates clockwise, passes through the zero return hole, and a reverse entry edge value (201) and a reverse exit edge value (202) are obtained, and an average value of the four values ​​is obtained as the zero return pulse value of the steering wheel.

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