A method of automatically zeroing a steering wheel of a wheeled robot

Abstract

The application discloses an automatic zero adjustment method for a steering wheel of a wheeled robot, which comprises a single-wheel automatic zero adjustment mode and a whole-machine automatic zero adjustment mode, and the single-wheel automatic zero adjustment operation is performed first, and then the whole-machine automatic zero adjustment operation is performed; the operation steps of the single-wheel automatic zero adjustment are as follows: a steering engine to be adjusted is controlled to rotate clockwise and counterclockwise at a uniform speed respectively, and first whole-machine current values and second whole-machine current values under the clockwise and counterclockwise conditions are obtained respectively; when the first whole-machine current value is detected to rise to a target threshold Ia, the current offset angle θ1 of the steering engine rotating clockwise is recorded; and when the second whole-machine current value is detected to rise to the target threshold Ia, the current offset angle θ2 of the steering engine rotating counterclockwise is recorded; and the wheel zero position offset information is obtained according to the offset angles θ1 and θ2 and is corrected. The application is based on solving the problems of straight-line driving and endurance, does not need any external equipment, and greatly accelerates the production and manufacturing speed and the on-site maintenance speed.

Description

TECHNICAL FIELD

[0001] The present application relates to a kind of wheeled robots, in particular, a kind of wheeled robot steering wheel automatic zeroing method. BACKGROUND

[0002] In the design and application of modern wheeled robots, the zero adjustment of steering gear is an important technical link to ensure the efficient and stable running of the robot. Especially in the scene involving steering control, the zero position of the steering gear of the wheeled robot with steering gear mainly affects the following aspects: 1) straight running; 2) tire, related structural wear; 3) power consumption and endurance. For example: the deviation of the zero position of the steering gear will cause the robot to deviate during running, which manifests as shaking or deviation during straight running, reducing the control accuracy; for example: if the steering gear cannot accurately maintain the zero position, the robot will have uneven tire wear during running, which will affect the service life of the tire and increase the maintenance cost; and the inaccuracy of the steering gear zero position will cause the robot to need more power to maintain straight running, increasing energy consumption and thus affecting the endurance of the robot, limiting its working time and efficiency. Therefore, in order to improve the performance and service life of the robot, steering gear zeroing is particularly important.

[0003] Currently, tooling is generally used to assist in steering gear zeroing, similar to the four-wheel alignment instrument of a car. For example, CN220649402U discloses a four-wheel alignment instrument convenient to operate, which can adapt to different wheelbase vehicle detection; CN117491038A discloses a four-wheel alignment instrument to solve the technical problems of easy damage to tires, difficulty in adjusting the measurement position and low accuracy of measurement results in the prior art; and CN117400175A discloses a four-wheel alignment clamp and automatic vehicle moving device for a car. However, the above patent documents have the following defects: 1) a complex set of equipment is required, increasing the complexity of the zeroing process and maintenance difficulty and increasing the cost; 2) it does not directly solve the problems of straight running and endurance.

[0004] In summary, the present application needs to design a wheeled robot steering wheel automatic zeroing method to solve the above technical problems. SUMMARY

[0005] The purpose of the present application is to overcome the above-mentioned deficiencies of the prior art and provide a wheeled robot steering wheel automatic zeroing method with simple operation, high zeroing accuracy and fast maintenance speed.

[0006] The technical solution of the present application is: a wheeled robot steering wheel automatic zeroing method, including single-wheel automatic zeroing mode and whole-machine automatic zeroing mode, and first performing single-wheel automatic zeroing operation, and then performing whole-machine automatic zeroing operation.

[0007] A. The operation steps of the single-wheel automatic zero adjustment are:

[0008] The rudder to be adjusted is controlled to rotate clockwise and counterclockwise at a constant speed, and the first and second whole-machine current values under the clockwise and counterclockwise conditions are obtained respectively;

[0009] When the first whole-machine current value is detected to rise to a target threshold Ia, the current offset angle θ1 of the clockwise rotating rudder is recorded, and when the second whole-machine current value is detected to rise to the target threshold Ia, the current offset angle θ2 of the counterclockwise rotating rudder is recorded;

[0010] The wheel zero position offset information is obtained according to the offset angles θ1 and θ2, and is corrected;

[0011] B. The operation steps of the whole-machine automatic zero adjustment are:

[0012] The robot is controlled to travel a target distance forward, and the forward offset amount under the target distance is obtained;

[0013] If it is judged that the forward offset amount does not meet the requirement, the deviation of the robot wheel offset zero position angle from the actual zero position is calculated according to the geometric relationship, and the deviation is corrected;

[0014] The robot is controlled to travel the target distance backward, and the backward offset amount under the target distance is obtained;

[0015] If it is judged that the backward offset amount does not meet the requirement, the deviation of the robot wheel offset zero position angle from the actual zero position is calculated according to the geometric relationship, and the deviation is corrected.

[0016] Further, the operation of the single-wheel automatic zero adjustment specifically includes the following steps:

[0017] S1-1: After entering the single-wheel automatic zero adjustment mode, a certain point is taken as a starting point, the robot is controlled to travel forward at a constant speed, the rudder to be adjusted is controlled to rotate clockwise at a constant speed, and when the whole-machine current is detected to rise to a target threshold Ia, the current offset angle θ1 of the rudder is recorded;

[0018] S1-2: The rudder to be adjusted is controlled to rotate counterclockwise at a constant speed, and when the whole-machine current is detected to rise to a target threshold Ia, the current offset angle θ2 of the rudder is recorded;

[0019] S1-3: The wheel zero position offset information is calculated according to the offset angles θ1 and θ2;

[0020] S1-4: control the robot to stop advancing and retreating to the starting point, and replace the next wheel to continue testing; after all the wheels complete single-wheel zero adjustment, perform a set of single-wheel zero adjustment operations on each wheel according to steps S1-1 to S1-3, until at least two sets of single-wheel zero adjustment are completed, then stop.

[0021] Further, the speed of the servo rotating clockwise and counterclockwise at a uniform speed is not greater than 0.3° / s.

[0022] Further, the target threshold Ia is obtained by the following method: before single-wheel automatic zero adjustment, the robot is lifted to measure the no-load current, and the target threshold Ia of the whole machine current is 1.2-1.5 times the no-load current.

[0023] Further, the wheel zero position offset information is obtained by the following formula: wheel zero position offset angle θ0=(θ1+θ2) / 2.

[0024] Further, the operation of the whole machine automatic zero adjustment specifically includes the following steps:

[0025] S2-1: after entering the whole machine automatic zero adjustment mode, taking a certain point as the starting point, the robot drives forward to obtain the displacement data of the robot driving forward;

[0026] S2-2: determine whether the robot drives a distance y, if not, return to step S2-1; if yes, stop advancing, obtain the displacement data of the robot, and obtain the lateral offset x of the forward driving;

[0027] S2-3: determine whether the lateral offset x of the forward driving meets the requirements, if yes, enter step S2-5; if not, calculate the deviation between the zero position offset angle and the actual zero position of the robot wheel according to the geometric relationship;

[0028] S2-4: correct the forward wheel zero position offset angle according to the calculated deviation;

[0029] S2-5: control the robot to retreat, and obtain the displacement data of the robot retreating;

[0030] S2-6: during the retreating process, determine whether the robot drives a distance y, if not, return to step S2-5; if yes, stop advancing, obtain the displacement data of the robot, and obtain the lateral offset x1 of the retreating;

[0031] S2-7: determine whether the lateral offset x1 of the retreating meets the requirements, if yes, stop zero adjustment; if not, calculate the deviation between the zero position offset angle and the actual zero position of the retreating robot wheel according to the geometric relationship;

[0032] S2-8: correct the wheel zero position offset angle in S2-7 according to the calculated deviation.

[0033] Further, in S2-3, the calculation method of the offset zero angle of the front wheels of the robot is as follows:

[0034] According to the driving distance y and the lateral offset x measured by the IMU, the curve is regarded as a part of a whole circle, and the radius of the whole circle is obtained as the driving radius r. According to the driving distance y and the lateral offset x, the driving radius r is obtained by the following formula:

[0035]

[0036] ;

[0037] The intersection point of the midlines of the two front wheels is taken as the center of the driving radius r, and according to the chassis model of the robot, the known conditions are obtained: the chassis length L and the width D; let the left front wheel offset zero angle be β and the right front wheel offset zero angle be γ, then the offset zero angles of the two front wheels are obtained by the following formula:

[0038]

[0039]

[0040] After β and γ are calculated, β and γ angles are respectively corrected in the opposite direction according to the actual zero of the wheels.

[0041] Further, in S2-7, the calculation method of the offset zero angle of the rear wheels of the robot is the same as the calculation method of the offset zero angle of the front wheels of the robot, and the driving direction of the rear wheels of the robot determines the backward direction, and the intersection point of the midlines of the two rear wheels is taken as the center of the driving radius r for calculation.

[0042] Further, in S2-7, it is judged whether the lateral offset x of the forward movement and the lateral offset x1 of the backward movement both satisfy the requirements, if yes, the zero adjustment is stopped; if the lateral offset x of the forward movement still does not satisfy the requirements, the next round of deviation correction is continued to return to step S2-1 until the requirements are satisfied.

[0043] The beneficial effects of the present application: on the one hand, from solving the fundamental problems of straight driving, endurance, etc., the single wheel zero adjustment and the whole machine zero adjustment are integrated into the robot, without any external equipment, and the multi-wheel positioning can be carried out in most places, greatly speeding up the production and on-site repair; on the other hand, single wheel zero adjustment and whole machine zero adjustment are two steps that depend on each other, only after single wheel zero adjustment, whole machine zero adjustment can be carried out, first single wheel automatic zero adjustment is carried out according to the current, to ensure that the zero position of each wheel is as accurate as possible, thereby reducing the resistance in the driving process, which means that the more accurate the zero adjustment of the wheel is in uniform driving, the less the current consumption is, greatly improving the energy efficiency; after completing the single wheel automatic zero adjustment, the deviation between the wheel zero position and the actual zero position has been significantly reduced, and then the whole machine automatic zero adjustment is carried out to further optimize the performance of the whole system, ensure the coordination between the wheels, enhance the stability and precision of the system, and finally realize more efficient operation. BRIEF DESCRIPTION OF DRAWINGS

[0044] Figure 1 is the working flow chart of single wheel automatic zero adjustment of the embodiment of the present application;

[0045] Figure 2 is the working flow chart of whole machine automatic zero adjustment of the embodiment of the present application;

[0046] Figure 3 is the calculation principle diagram of driving radius r in whole machine automatic zero adjustment of the embodiment of the present application;

[0047] Figure 4 is the calculation principle diagram of left front wheel offset zero position angle β in whole machine automatic zero adjustment of the embodiment of the present application;

[0048] Figure 5 is the calculation principle diagram of right front wheel offset zero position angle γ in whole machine automatic zero adjustment of the embodiment of the present application. DETAILED DESCRIPTION

[0049] The present application will be further described in detail below in combination with the drawings and specific embodiments of the present application.

[0050] Generally, when a new robot or an old robot on-site replaces a wheel, or in the case of long time wear and tear of the wheel, etc., the wheel needs to be adjusted to zero, the present application includes two steps of single wheel automatic zero adjustment and whole machine automatic zero adjustment, first single wheel automatic zero adjustment is carried out, and then whole machine automatic zero adjustment is carried out. The operator can select single wheel automatic zero adjustment mode or whole machine automatic zero adjustment mode on the terminal or the display screen of the robot, and send instructions to enter the corresponding zero adjustment mode. The specific method is as follows:

[0051] 1. Single wheel automatic zero adjustment according to current:

[0052] The principle of single-wheel automatic zero adjustment is that the wheel has the minimum resistance after accurate zero adjustment, and the more accurate the zero adjustment of the wheel is, the smaller the consumed current is in the uniform driving process. Figure 1 The method specifically comprises the following steps:

[0053] S101: After entering the single-wheel automatic zero adjustment mode, the robot is controlled to drive forward at a uniform speed from a starting point, and a servo to be adjusted is controlled to rotate clockwise at a uniform speed, and when the whole-machine current is detected to rise to a target threshold Ia, the current offset angle θ1 of the servo is recorded;

[0054] S102: The servo to be adjusted is controlled to rotate counterclockwise at a uniform speed, and when the whole-machine current is detected to rise to the target threshold Ia, the current offset angle θ2 of the servo is recorded;

[0055] S103: The wheel zero offset angle θ0 is calculated according to the offset angle θ1 and the offset angle θ2 and is corrected;

[0056] S104: The robot is controlled to stop driving forward and backward to the starting point, and the next wheel is continued to be tested; after all the wheels complete single-wheel zero adjustment, a set of single-wheel zero adjustment operations are performed on the wheels according to the steps S101-S103, until two sets of single-wheel zero adjustment are completed, and then the method stops.

[0057] In the single-wheel zero adjustment, the offset angle of the servo refers to the angle offset of the servo relative to the zero point of the servo when the servo rotates clockwise or counterclockwise to reach the whole-machine current threshold.

[0058] In the steps S101 and S102, the speed of the servo rotating clockwise and counterclockwise at a uniform speed is not greater than 0.3° / s, and if the rotation is too fast, it is difficult to identify the trend of the current change.

[0059] In addition, the method for obtaining the current target threshold Ia is that before the zero adjustment operation, the robot is first lifted to measure the no-load current, and the target threshold Ia of the whole-machine current is 1.2-1.5 times the no-load current, and preferably 1.4 times. In this embodiment, the no-load current is measured in the lifted state, so that the real current value of the robot without any load can be obtained, the interference of the load on the current measurement is avoided, and the baseline data is ensured to be accurate; by setting the target threshold to be 1.2-1.5 times the no-load current, a certain margin can be provided for the robot during operation, so that the overload condition can be effectively prevented, and the abnormal rise of the current caused by the sudden increase of the load can be avoided.

[0060] In the step S103, the calculation formula of the wheel zero offset angle θ0 is θ0=(θ1+θ2) / 2.

[0061] The calculation principle is that in the case of straight walking of the robot and deviation of the wheel from the zero position, the consumed current will increase, and the more the deviation from the zero position, the greater the current. Since the relationship between the angle of deviation of the wheel from the zero position and the current is approximately consistent in clockwise and counterclockwise rotation, (θ1+θ2) / 2 can be used as the angle of deviation of the wheel from the zero position, which helps to keep the robot stable during walking and avoid tilting or instability caused by deviation. It can be said that the embodiment is simple to calculate, ensures consistency and reliability during movement of the steering engine, and enables the entire robot system to run more smoothly and efficiently.

[0062] In the above step S104, after completing the first single-wheel zeroing, it may be found that the zero position or rotation characteristics of each wheel are affected by external factors such as ground friction, wheel wear, or uneven load. Therefore, a set of zeroing operations can help further improve the accuracy of the robot during movement and ensure that each wheel accurately reflects its position. The embodiment is a four-wheel robot, so it needs to individually zero four wheels, and each wheel needs to be zeroed at least twice.

[0063] It can be said that the embodiment uses current for single-wheel automatic zeroing. On the one hand, the current signal can monitor and feedback the state of the wheel in real time, so as to realize immediate adjustment, ensure that the zeroing process is fast and effective, and in the process of walking, the current zeroing can automatically adjust according to the load change, road conditions and other conditions, keep the wheel in the best working state, and has high dynamic adaptability. On the other hand, the difference between the actual position and the target position of the wheel can be accurately judged by the change of the current, so as to carry out accurate zeroing. Compared with mechanical zeroing, current zeroing can reduce the dependence on mechanical parts, reduce wear and failure risk, prolong the service life of the equipment, and ensure the accuracy of the direction and position control of the robot, providing a reliable benchmark for the subsequent navigation and positioning of the robot when performing tasks. Moreover, it does not require complex mechanical structures, simplifying the design and manufacturing process.

[0064] 2. Automatic zeroing of the entire machine according to deviation:

[0065] The principle of whole-machine zeroing is that when deviating, the walking curve of the robot is a large circle. According to the running distance and offset recorded by the IMU, the deviation of each wheel from the actual zero position can be obtained through geometric calculation, and the zero position can be corrected in the opposite direction with the deviation, thereby achieving whole-machine zeroing. As shown in FIG. 8, the specific steps include the following steps: Figure 2

[0066] S201: After entering the automatic whole-machine zeroing mode, the robot drives forward from a certain point to obtain the displacement data of the robot detected by the IMU;

[0067] ​S202: Determine whether the robot travels a distance y, if not, return to step S201; if yes, stop advancing, obtain the displacement data of the robot detected by the IMU, and obtain the lateral offset x of the advancing;

[0068] S203: Determine whether the lateral offset x of the advancing meets the requirements, if yes, go to step S205; if not, calculate the deviation of the wheel offset zero angle from the actual zero position according to the geometric relationship;

[0069] S204: Correct the wheel offset zero angle according to the calculated deviation;

[0070] S205: Control the robot to retreat, and obtain the displacement data of the robot detected by the IMU;

[0071] S206: During the retreat, determine whether the robot travels a distance y, if not, return to step S205; if yes, stop advancing, obtain the displacement data of the robot detected by the IMU, and obtain the lateral offset x1 of the retreat;

[0072] S207: Determine whether the lateral offset x of the advancing and the lateral offset x1 of the retreat both meet the requirements, if yes, stop zeroing; if not, calculate the deviation of the wheel offset zero angle from the actual zero position according to the geometric relationship;

[0073] S208: Correct the wheel offset zero angle according to the calculated deviation.

[0074] Specifically, in step S202, after single-wheel automatic zeroing, the robot is controlled to travel along a straight line at a long distance. Once the robot deviates, the travel trajectory of the robot becomes a curve. If the lateral offset of the advancing is not greater than the target offset, there is no need to perform whole-machine zeroing, if it is greater than the target offset, the deviation of the wheel offset zero angle from the actual zero position of the robot is calculated according to the geometric relationship.

[0075] The deviation calculation method in step S203 is as follows:

[0076] First, according to the travel distance y and the lateral offset x measured by the IMU, the curve can be regarded as a part of a whole circle, so that the radius r of the whole circle can be obtained, as shown in Figure 3 The robot is approximated as a point, and the travel radius r is obtained according to the travel distance y and the lateral offset x by the following formula:

[0077]

[0078]

[0079] Then, since the deviation of the wheel zero position from the actual zero position is small after completing the single round automatic zero adjustment, the direction of the front wheels determines the direction of the forward movement, and the influence of the rear wheels can be ignored. Therefore, after determining the travel radius r, since the intersection of the midline of the left front wheel and the left rear wheel is the center of the travel radius r circle, the deviation of the two front wheels from the actual zero position can be calculated according to the chassis model of the robot. As shown in Figure 4 and Figure 5 shown: let the left front wheel deviate from the zero position angle β, the right front wheel deviate from the zero position angle γ, the chassis length L and the width D are known, then:

[0080]

[0081]

[0082] After calculating β and γ, it is known that the actual zero position of the wheel needs to be corrected in the opposite direction by β and γ angles respectively.

[0083] Similarly, in steps S206 and S207, the direction of the rear wheels of the robot determines the direction of the backward movement, and the influence of the front wheels can be ignored. Therefore, the deviation of the zero position angle of the rear wheels is calculated similarly to the front wheels, which will not be described in detail here. In addition, in step S207, only the lateral deviation x1 of the backward movement can be determined to meet the requirements. When the lateral deviation x of the forward movement and the lateral deviation x1 of the backward movement are both determined to meet the requirements, if the lateral deviation x of the forward movement still does not meet the requirements, the next round of deviation correction needs to be returned to step S201, until the requirements are met.

[0084] 3. Hardware configuration.

[0085] The wheels responsible for steering are equipped with steering rudders, and the robot is equipped with an IMU for detecting robot travel displacement data and a current sensor for measuring the current of the whole machine. The robot is placed on a non-smooth road surface with uniform material for travel, and the robot can communicate with the terminal, which can be a mobile phone or a computer, etc. The zero adjustment operation can be controlled through the terminal.

[0086] In summary, the present application is one aspect from the solution of straight travel, endurance and other fundamental problems, the single wheel zero and whole machine zero integration to the robot inside, without any external equipment, in most places can be multi-wheel positioning, greatly speed up the production and on-site repair speed; on the other hand, single wheel zero and whole machine zero are two steps of mutual dependence, only after single wheel zero, can whole machine zero, first according to the current single wheel automatic zero, ensure that the zero of each wheel as accurate as possible, thereby reducing the resistance in the process of travel, which means that in uniform motion, the more accurate the zero of the wheel, the less the current consumption, greatly improve the energy efficiency; after the completion of single wheel automatic zero, the deviation between the wheel zero and the actual zero has been significantly reduced, and then the whole machine automatic zero further optimizes the performance of the whole system, ensures the coordination between the wheels, enhances the stability and precision of the system, and finally realizes more efficient operation.

Claims

1. A method of automatically zeroing a steering wheel of a wheeled robot, characterized in that, The single-wheel automatic zero adjustment mode and the whole machine automatic zero adjustment mode are included, and the single-wheel automatic zero adjustment operation is performed first, and then the whole machine automatic zero adjustment operation is performed. A. The operation steps of the single-wheel automatic zero adjustment are: The rudder to be adjusted is controlled to rotate clockwise and counterclockwise at a constant speed, and first and second whole machine current values under the conditions of clockwise and counterclockwise rotation are obtained respectively; When the first whole machine current value is detected to rise to a target threshold Ia, the current offset angle θ1 of the rudder rotating clockwise is recorded; and when the second whole machine current value is detected to rise to the target threshold Ia, the current offset angle θ2 of the rudder rotating counterclockwise is recorded; The wheel zero position offset information is obtained according to the offset angle θ1 and the offset angle θ2 and is corrected. B. The operation steps of the whole machine automatic zero adjustment are: The robot is controlled to travel a target distance forward, and a forward offset is obtained under the target distance; If it is judged that the forward offset does not meet the requirement, the deviation of the robot wheel offset zero position angle from the actual zero position is calculated according to the geometric relationship, and the deviation is corrected. The robot is controlled to travel the target distance backward, and a backward offset is obtained under the target distance; If it is judged that the backward offset does not meet the requirement, the deviation of the robot wheel offset zero position angle from the actual zero position is calculated according to the geometric relationship, and the deviation is corrected.

2. The method of automatically zeroing the steering wheels of a wheeled robot of claim 1, wherein, The operation of the single-wheel automatic zero adjustment specifically includes the following steps: S1-1: After entering the single-wheel automatic zero adjustment mode, a certain point is taken as a starting point, the robot is controlled to travel forward at a constant speed, and the rudder to be adjusted is controlled to rotate clockwise at a constant speed; when the whole machine current is detected to rise to a target threshold Ia, the current offset angle θ1 of the rudder is recorded; S1-2: The rudder to be adjusted is controlled to rotate counterclockwise at the same speed, and when the whole machine current is detected to rise to the target threshold Ia, the current offset angle θ2 of the rudder is recorded; S1-3: The wheel zero position offset information is calculated according to the offset angle θ1 and the offset angle θ2; S1-4: The robot is controlled to stop forward and backward to the starting point, and the next wheel is continued to be tested; after all the wheels complete the single-wheel zero adjustment, a group of single-wheel zero adjustment operations are performed on the wheels according to the steps S1-1 to S1-3, until at least two groups of single-wheel zero adjustment are completed, and then the operation is stopped.

3. The method of automatically zeroing the steering wheel of a wheeled robot of claim 1, wherein, The speed of the rudder rotating clockwise and counterclockwise at a constant speed is not greater than 0.3° / s.

4. The method of automatically zeroing the steering wheel of a wheeled robot of claim 1, wherein, The target threshold Ia is obtained by: before the single-wheel automatic zero adjustment operation, the robot is first lifted to measure the no-load current, and the target threshold Ia of the whole machine current is 1.2-1.5 times the no-load current.

5. The method of automatically zeroing the steering wheel of a wheeled robot of claim 1, wherein, The wheel zero position offset information is obtained by the following formula: wheel zero position offset angle θ0=(θ1+θ2) / 2.

6. The method of automatically zeroing the steering wheel of a wheeled robot of claim 1, wherein, The operation of the whole machine automatic zero adjustment specifically includes the following steps: S2-1: After entering the whole machine automatic zero adjustment mode, a certain point is taken as a starting point, and the robot travels forward to obtain the displacement data of the robot; S2-2: It is judged whether the robot travels a distance y, if not, return to step S2-1; if yes, stop forward, obtain the displacement data of the robot, and obtain the lateral offset x of forward travel; S2-3: Determine whether the lateral offset x of the forward movement meets the requirements, if yes, go to step S2-5; if not, calculate the deviation between the robot wheel offset zero angle and the actual zero position according to the geometric relationship; S2-4: According to the calculated deviation, correct the forward wheel offset zero angle; S2-5: Control the robot to move backward and obtain the displacement data of the robot; S2-6: During the backward movement, determine whether the robot has traveled a distance y, if not, return to step S2-5; if yes, stop the forward movement, obtain the displacement data of the robot, and get the backward lateral offset x1; S2-7: Determine whether the lateral offset x1 of the backward movement meets the requirements, if yes, stop the zero adjustment; if not, calculate the deviation between the backward robot wheel offset zero angle and the actual zero position according to the geometric relationship; S2-8: According to the calculated deviation, correct the wheel offset zero angle in S2-7.

7. The method of automatically zeroing a steering wheel of a wheeled robot of claim 6, wherein, In S2-3, the calculation method of the forward wheel offset zero angle of the robot is as follows: According to the travel distance y measured by the IMU and the forward lateral offset x, the travel trajectory of the robot is regarded as a part of a whole circle, and the radius of the whole circle is obtained as the travel radius r. According to the travel distance y and the forward lateral offset x, the travel radius r is obtained by the following formula: ； The intersection of the midlines of the two front wheels is taken as the center of the travel radius r, and according to the chassis model of the robot, the known conditions are obtained: chassis length L, width D; let the left front wheel offset zero angle be β, and the right front wheel offset zero angle be γ, then the offset zero angles of the two front wheels are obtained by the following formula: ； After calculating β and γ, the actual zero position of the wheel is corrected in the opposite direction according to β and γ angles respectively.

8. The method of automatically zeroing a steering wheel of a wheeled robot of claim 7, wherein, In S2-7, the calculation method of the backward wheel offset zero angle of the robot is the same as that of the forward wheel offset zero angle of the robot, and the backward direction is determined by the direction of the rear wheel of the robot. The intersection of the midlines of the two rear wheels is taken as the center of the travel radius r for calculation.

9. The method of automatically zeroing a steering wheel of a wheeled robot of claim 6, wherein, In S2-7, it is determined Whether the forward lateral offset x and the backward lateral offset x1 meet the requirements, if yes, stop the zero adjustment; if the forward lateral offset x still does not meet the requirements, continue to return to step S2-1 for the next round of deviation correction until the requirements are met.

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