A multi-steering-wheel robot motion chassis steering angle compensation calibration method and system thereof

Abstract

This invention provides a method and system for calibrating the rudder angle compensation of a multi-rudder robot chassis. The method includes the following steps: controlling the chassis to sequentially execute calibration actions in segments; collecting the wheel speed, rudder angle, and chassis positioning pose of each rudder wheel i at time n in each stage; calculating the relative pose change of the chassis before and after each stage of calibration actions based on the installation position and wheel diameter of each rudder wheel to determine the corresponding rudder angle compensation value; using the compensated rudder angles of each rudder wheel, executing the calibration actions again in segments sequentially, calculating the positional offset between the preceding and following calibration actions to determine the overall rudder angle compensation value for the subsequent calibration actions; and constructing a rudder wheel difference compensator to compensate for the downward rudder angle of each rudder wheel during chassis movement. This improves the applicability of multi-rudder mobile robots in complex and high-precision scenarios.

Description

TECHNICAL FIELD

[0001] The present application relates to mobile robot calibration technology, and in particular to a multi-steering wheel robot motion chassis steering angle compensation calibration method and a calibration system thereof. BACKGROUND

[0002] In the field of mobile robot chassis technology, the multi-steering wheel chassis has become the core executive component of high-precision and high-flexibility mobile operation scenarios due to its excellent omnidirectional motion performance. The multi-steering wheel chassis refers to a mobile robot chassis equipped with two or more wheels with active steering and driving functions. Its core structural feature is that each wheel is configured with an independent steering motor and a walking motor. Through coordinated control of the steering angle and speed of each wheel, high flexibility and high precision omnidirectional motion can be achieved. Compared with traditional single-steering wheel or fixed wheel chassis, it can better adapt to path planning and position adjustment requirements in complex operation environments, and is therefore widely used in heavy material handling, high-flexibility logistics and warehousing, special operations and installation, large service robots, and other scenarios with high requirements for motion flexibility and precision.

[0003] For motion control of the multi-steering wheel chassis, the accuracy of the steering wheel zero position is a core prerequisite for ensuring motion control accuracy. In ideal working conditions, the mechanical zero position of the steering wheel should coincide completely with the geometric zero position defined by the control algorithm (for example, the wheel is defined as 0° when it points to the front of the chassis). At this time, the steering instruction output by the controller based on the geometric zero position can accurately translate into the actual motion direction of the chassis. However, in actual engineering applications, the accuracy of the steering wheel zero position of the multi-steering wheel chassis is easily affected by various factors, resulting in deviations between the ideal zero position and the actual zero position.

[0004] For example, the steering motor may experience zero drift over a long period of time. The above two factors directly cause a basic deviation between the mechanical zero position of the steering wheel and the geometric zero position defined by the algorithm. In addition, the steering angle encoder configured for the steering motor also has inaccurate feedback in practice, and this feedback deviation has obvious angle dependence, i.e., the steering angle deviation values at different steering wheel angles differ significantly, causing the controller to be unable to obtain the true steering angle information of the steering wheel. Furthermore, the gear meshing gap of the steering wheel and the deformation of the transmission mechanism also change with the changes in the motion action of the chassis, for example, the gear force conditions differ under different motion states of the chassis such as straight running, steering, and diagonal running, thereby causing the steering angle deviation values to fluctuate.

[0005] Therefore, if the above steering angle deviation is not effectively compensated, it will directly cause a deviation between the actual motion direction of the chassis and the expected direction of the controller, severely reducing the motion control accuracy of the chassis. In heavy material handling scenarios, this deviation may cause material collisions and inaccurate positioning. In special operation and installation scenarios, the deviation in operation accuracy may cause safety hazards.

[0006] However, in the existing technology, most of the rudder angle compensation schemes for multi-rudder wheel chassis only consider a single error factor (such as only compensating for mechanical installation errors) or adopt a compensation method with a fixed compensation coefficient. Therefore, they do not fully consider the coupling effect of robot chassis movement and steering motor rotation angle on rudder angle deviation. As a result, in practice, the compensation effect is often poor and cannot meet the needs of high-precision operation scenarios.

[0007] Therefore, based on the above situation, there is an urgent need in this field for a rudder angle compensation method that can take into account both the chassis motion and the steering motor angle, in order to solve the problem of unsatisfactory motion control accuracy caused by rudder angle deviation in existing multi-rudder chassis, and to improve the applicability of multi-rudder mobile robots in complex and high-precision scenarios. Summary of the Invention

[0008] Therefore, the main objective of this invention is to provide a method and system for calibrating the rudder angle of a multi-rudder robot's motion chassis, in order to solve the problems mentioned in the background art.

[0009] To achieve the above objectives, according to one aspect of the present invention, a method for calibrating the rudder angle compensation of a multi-rudder robot motion chassis is provided, comprising the following steps:

[0010] The control chassis executes calibration actions sequentially in segments, collecting the wheel speed, rudder angle, and chassis positioning attitude of each steering wheel i at time n in each stage; and calculating the relative attitude change of the chassis before and after each stage of calibration actions based on the installation position and wheel diameter of each steering wheel, in order to determine the corresponding rudder angle compensation value. ;

[0011] use Compensate the rudder angles of each steering wheel, and then perform the calibration actions in segments again in sequence. Calculate the positional offset between each calibration action to determine the overall rudder angle compensation value for the subsequent calibration actions. ;

[0012] according to and Construct a steering wheel differential compensator to compensate for the downward steering angle of each steering wheel when the chassis moves.

[0013] In a possible preferred embodiment, the rudder angle compensation value The calculation steps include:

[0014] Based on the installation position of each steering wheel, the linear velocity and angular velocity of each steering wheel along the X and Y axes in the vehicle coordinate system are calculated before and after each stage of calibration action to determine the ideal relative posture change of the chassis. ;

[0015] Based on the collected positioning and pose data, the actual relative pose changes of the chassis are determined before and after each stage of the calibration action. ;

[0016] Pick and An optimization model is constructed based on the angle change data to solve for the rudder angle compensation value of each rudder wheel when performing the calibration action at each stage. .

[0017] In a possible preferred embodiment, the total steering wheel rudder angle compensation value The calculation steps include:

[0018] The calibration motion is decomposed into sequential actions. The ideal trajectory of the subsequent action is determined based on the trajectory of the preceding action. The full rudder wheel angle compensation value for the subsequent action is determined based on the distance between the end points of the ideal and actual trajectories. .

[0019] In a possible preferred embodiment, wherein the following is used The steps for compensating for the rudder angle of each steering wheel include:

[0020] According to the installation position of each steering wheel wheel diameter Wheel speed , and rudder angle Establish a formula for calculating the linear velocity of the steering wheel, and use... Compensation rudder angle :

[0021] .

[0022] In a possible preferred embodiment, wherein according to and The steps for constructing a steering wheel differential compensator include:

[0023] Define the sign of the steering wheel's rotational speed when performing each stage of the calibration action, and assign compensation values. and By associating the rudder angle with the corresponding stage calibration action, an interpolation table is established and an interpolation compensator is constructed accordingly.

[0024] In a possible preferred embodiment, the calibration action includes:

[0025] The steering wheel angle is rotated to 0° in the vehicle coordinate system to perform open-loop straight forward and straight backward movements.

[0026] The steering wheel angle is rotated to 90° in the vehicle coordinate system to perform an open-loop linear left lateral movement and a linear right lateral movement.

[0027] The steering wheel angle is rotated to -90° in the vehicle coordinate system to perform open-loop linear rightward and linear leftward movements.

[0028] To achieve the above objectives, according to another aspect of the present invention, a rudder angle compensation calibration system for a multi-rudder robot motion chassis is also provided, comprising:

[0029] The storage unit contains a program that implements the steps of the multi-steering wheel robot motion chassis rudder angle compensation calibration method as described above, so that the control unit, data acquisition unit and processing unit can retrieve and execute it as needed.

[0030] The control unit is used to control the segmented execution of calibrated actions by the motion chassis of the multi-steering wheel robot.

[0031] The data acquisition unit is used to collect the wheel speed, rudder angle, and chassis positioning posture of each steering wheel at each stage.

[0032] The processing unit is used to calculate the relative attitude changes of the chassis before and after each stage of calibration action based on the known installation position and wheel diameter of each steering wheel, and to determine the corresponding steering angle compensation value. Compensate the rudder angles of each steering wheel; based on the data collected after performing the calibration actions in sequence again, calculate the positional offset between the previous and subsequent calibration actions to determine the compensation value for the rudder angles of all steering wheels in the subsequent calibration action. ;according to and Construct a steering wheel differential compensator and calculate the compensation value for the steering angle issued by each steering wheel.

[0033] To achieve the above objectives, according to another aspect of the present invention, a computer-readable storage medium is provided having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the multi-steering wheel robot motion chassis rudder angle compensation calibration method as described above.

[0034] The multi-wheel robot motion chassis rudder angle compensation calibration method and system provided by this invention ingeniously designs a segmented calibration action to collect speed data under each stage of the action, establish a rudder angle compensation mechanism for each rudder under a single action, and perform the calibration action again based on this as a basis. By comparing the angle changes in the ideal pose and the actual pose changes, a rudder angle compensation mechanism for the entire rudder is constructed. This fully considers the actual impact of compensating for single and multiple rudders on the accuracy of the chassis when performing motion actions, and solves the problem of insufficient motion control accuracy caused by the deviation between the ideal and actual chassis motion trajectory after rudder angle compensation in existing multi-wheel chassis. This improves the applicability of multi-wheel mobile robots in complex and high-precision scenarios. Attached Figure Description

[0035] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. In the drawings:

[0036] Figure 1 This is a schematic diagram of the existing three-wheeled robot motion chassis model structure;

[0037] Figure 2 This is a schematic diagram of the logical steps of the multi-steering wheel robot motion chassis rudder angle compensation calibration method of the present invention;

[0038] Figure 3 This is a schematic diagram of the calibration action steps in the method of the present invention;

[0039] Figure 4 This is a schematic diagram comparing the ideal trajectory and the actual trajectory when performing the calibration action in the method of the present invention;

[0040] Figure 5 This is a schematic diagram illustrating the geometric relationship between the ideal trajectory and the actual trajectory when performing the calibration action in the method of the present invention;

[0041] Figure 6 This is a schematic diagram illustrating the geometric relationship between the ideal trajectory and the actual trajectory established based on the preceding and following calibration actions in the method of the present invention.

[0042] Figure 7 This is a schematic diagram of the trajectory of the multi-steering wheel chassis performing calibration actions before compensating and calibrating the steering wheels in a test example of the method of the present invention.

[0043] Figure 8 This is a schematic diagram of the ideal trajectory of a multi-steering wheel chassis performing calibration actions in a test example of the method of the present invention;

[0044] Figure 9 This is a schematic diagram of the trajectory of the multi-steering wheel chassis performing calibration actions after compensating and calibrating the steering wheels in a test example of the method of the present invention.

[0045] Figure 10 This is a schematic diagram of the rudder angle compensation calibration system for the multi-rudder robot motion chassis of the present invention. Detailed Implementation

[0046] To enable those skilled in the art to better understand the technical solutions of the present invention, the specific technical solutions of the present invention will be clearly and completely described below in conjunction with embodiments, so as to help those skilled in the art further understand the present invention. Obviously, the embodiments described in this application are merely some embodiments of the present invention, and not all embodiments. It should be noted that, for those skilled in the art, the embodiments and features in the embodiments of this application can be combined with each other without departing from the concept of the present invention and without conflict. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort should fall within the disclosure and protection scope of the present invention.

[0047] Furthermore, the terms "first," "second," "S100," "S200," etc., used in the specification, claims, and drawings of this invention are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such features can be interchanged where appropriate so that embodiments of the invention described herein can be implemented in orders other than those described herein. At the same time, the stages described in each step are not necessarily to be implemented in the same step; it should be understood that the implementation order of the contents of each step stage can be adjusted and interchanged without violating the inventive concept, so that embodiments of the invention described herein can be implemented in orders other than those described herein. Additionally, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion. Unless otherwise expressly specified and limited, the terms "set," "arrange," "install," "connect," and "link" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; a mechanical connection or an electrical connection; a direct connection or an indirect connection through an intermediate medium; or a connection within two elements. Those skilled in the art can understand the specific meaning of the above terms in this case based on the specific circumstances and in conjunction with existing technology.

[0048] To address the issue of unsatisfactory motion control accuracy caused by significant deviations between the ideal and actual chassis motion after compensation for rudder angle deviations in existing multi-rudder chassis, such as... Figures 2 to 6 As shown, this invention provides a method for calibrating the rudder angle compensation of a multi-rudder robot's motion chassis, the example steps of which include:

[0049] Step S100

[0050] The control chassis executes calibration actions sequentially in segments, collecting the wheel speed, rudder angle, and chassis positioning posture of each steering wheel i's travel motor at time n in each stage; and calculating the relative posture change of the chassis before and after each stage calibration action based on the installation position and wheel diameter of each steering wheel, in order to determine the corresponding rudder angle compensation value. .

[0051] Specifically, such as Figure 1 As shown, this example uses a three-steering wheel robot chassis model. The motion control parameters of this type of three-steering wheel chassis are mainly related to the wheel diameter of the steering wheel motor, the steering motor rudder angle compensation, and the coordinates of the steering motor and the walking motor in the vehicle coordinate system (e.g., ...). Figure 1 As shown, the installation position and the calibration accuracy of the positioning equipment are related to the coordinate system established with the chassis rotation center as the origin, the chassis forward direction as the X-axis, and the direction perpendicular to the left of the X-axis as the Y-axis.

[0052] Therefore, in order to find the deviation between the ideal and actual motion trajectory of the multi-steering wheel chassis, this invention designs a set of calibration actions, such as... Figures 3 to 4 As shown, the calibration process is divided into stages:

[0053] The steering wheel angle is rotated to 0° in the vehicle coordinate system, and action 1 is executed: open-loop straight forward movement; action 2 is open-loop straight backward movement.

[0054] The steering wheel angle is rotated to 90° in the vehicle coordinate system, and action 3 is executed: open-loop linear left lateral movement and action 4 is executed: open-loop linear right lateral movement.

[0055] The steering wheel angle is rotated to -90° in the vehicle coordinate system, and action 5 is executed: open-loop straight right lateral movement and action 6 is executed: open-loop straight left lateral movement.

[0056] Since the rudder angle of a multi-rudder vehicle may deviate from its zero position due to inaccurate installation angles or inaccurate encoder zeroing, the zero position of the rudder angle can be calibrated using "Action 1: Open-loop linear forward movement". However, due to errors in the meshing of the rudder wheel gear system or mechanical installation errors, two new sets of rudder angle compensations will be generated in the forward and reverse states of the chassis. Therefore, "Action 2: Open-loop linear reverse movement" is required for calibration.

[0057] In fact, due to the inaccurate configuration of the rudder angle encoder, the error of the rudder wheel during forward and backward translation and the error during left and right lateral movement are inconsistent. Therefore, it is necessary to add motion sampling at several angles, calibrate the rudder angle compensation under forward and backward operation at different angles, and form an interpolation table for rudder angle compensation.

[0058] Actions 3 through 6 are designed to obtain rudder angle compensation for forward and backward movements at different angles. Since multi-rudder vehicles support omnidirectional movement, their rudder angle range is generally greater than ±90°. Therefore, this example describes sampling at ±90° rudder angles. In practice, this can be modified based on accuracy requirements and rudder angle range limitations.

[0059] Furthermore, the aforementioned open-loop motion refers to motion that relies entirely on pre-set instructions and internal models during the motion process. In this example, the odometer is synthesized based solely on the current speed of the chassis motor and the motor installation position, and motion control is performed based on the odometer data.

[0060] By controlling the multi-steering wheel chassis to execute the above actions in sequence, and collecting the wheel speed, steering angle and current positioning posture of each walking motor in real time during the execution, a multi-steering wheel mileage synthesis model is first established to provide a basis for subsequent model optimization and compensation calculation.

[0061] Specifically, the process of establishing this multi-steering wheel odometer synthesis model includes: based on the known that there are i steering wheel groups (a combination of travel motors and steering motors) in the multi-steering wheel chassis, the installation position of the travel motor of the i-th steering wheel group... wheel diameter Wheel speed , and rudder angle Then the linear velocity of the i-th traveling motor in the X-direction in the vehicle coordinate system can be calculated. and along the Y direction Linear velocity:

[0062] Formula 1

[0063] Assumption Let X represent the linear velocity, Y represent the linear velocity, and Y represent the angular velocity of the chassis in the vehicle coordinate system, respectively. Then the following relationship holds:

[0064] Formula 2

[0065] in,

[0066] Formula 3

[0067] The above is the basic formula for synthesizing multi-steering wheel mileage.

[0068] After completing the multi-steering wheel odometer synthesis model, based on the following two prerequisites, a single-action rudder angle compensation optimization model is constructed to calculate the corresponding rudder angle compensation value. .

[0069] Condition 1: Assume that the diameter and installation position of the motor wheel in the steering wheel assembly are accurate.

[0070] Condition 2: Since there is a fixed angle deviation between the actual steering angle and the ideal angle of each steering motor, this fixed deviation will not change within a fixed action, but will change under different actions in reality.

[0071] For example, let's construct an optimization model using "Action 1: Open-loop straight-line forward movement" as an example. For a multi-steering wheel model with i steering wheel groups, according to condition 2, we assume that the fixed deviations between the actual steering angle and the ideal steering angle of the i steering wheels are respectively... This deviation is referred to as rudder angle compensation. Here, the superscript represents the action sequence number, and the subscript represents the rudder wheel sequence number.

[0072] At every moment of chassis movement, the wheel speed of the drive motor can be recorded in real time during the movement. and steering motor rudder angle Furthermore, according to condition 1, the installation location of the walking motor is... and wheel diameter Referring to Formula 1, the formula for calculating the linear velocity of the travel motor with rudder angle compensation during the execution of Action 1 can be obtained:

[0073] Formula 4

[0074] Therefore, according to Formula 2, the linear velocity, linear velocity, and angular velocity of the chassis in the X-axis direction and Y-axis direction in the vehicle coordinate system at each moment can be obtained. ,in Indicates the current time. The time when the action begins. This represents the time when the action ends. Integrating the velocity data at each moment yields the change in the chassis's relative pose after performing the action.

[0075] Formula 5

[0076] in, Indicates in The change in pose relative to the initial pose at time t. This indicates that there was no change at the start time. This represents the ideal change in the chassis relative to the initial pose after the motion is completed. Only the angle change data is needed here. .

[0077] On the other hand, since the chassis is equipped with positioning devices, its positioning posture can be read in real time during chassis movement. The chassis posture before the action can then be obtained. and chassis position after the action is performed This allows us to obtain the actual relative positional changes of the chassis. Here, only the angle change data is needed:

[0078]

[0079] Finally, an optimization model can be constructed based on the above data:

[0080] Formula 6

[0081] Where f represents the cost function of the optimization model, which can be set according to the actual situation. After solving the model, we can obtain... Following the example above, similarly performing the optimization on actions 2 through 6 will yield the rudder angle compensation for each rudder wheel under different actions: .

[0082] Then, the rudder angle compensation results are applied to the angle of each action and each rudder wheel, so that when the multi-rudder wheel chassis performs an open-loop straight-line action, it also travels in a straight line in actual space. Without the above compensation, the chassis would travel in an arc in actual space.

[0083] Furthermore, it should be noted that in the optimization model of Formula 6, only the relative angle change between mileage motion and actual motion is optimized. This is because under conditions 1 and 2, the angle change during chassis linear motion is only affected by the rudder angle compensation parameter.

[0084] Step S200

[0085] use Compensate the rudder angles of each steering wheel, and then perform the calibration actions in segments again in sequence. Calculate the positional offset between each calibration action to determine the overall rudder angle compensation value for the subsequent calibration actions. .

[0086] Specifically, after completing the single steering wheel angle compensation in step S100, when the multi-steering wheel chassis performs an open-loop straight-line movement, the chassis should ideally move in a straight line. However, after running "Action 1~Action 6", the following situation still occurs: Figure 4 The situation is shown in the diagram on the right.

[0087] For ease of observation, Figure 4 The portion of the ideal trajectory that overlaps has been offset laterally. After the chassis completes actions 1 through 6, the forward and backward trajectories in the ideal trajectory should overlap, and the longitudinal movement trajectory should be perpendicular to the lateral movement trajectory. However, due to errors in the steering wheel gear meshing and inaccuracies in the steering motor encoder, the actual trajectories will not be ideally parallel and overlapped. To eliminate this error, secondary compensation of the steering angle is required.

[0088] Because the chassis will still move in a straight line even after all the rudder angles are changed to the same angle during linear movement of multiple rudder wheels, this example will construct a full-motion rudder angle compensation optimization model to compensate for the rudder angles of all six rudder wheels for each of the six movements. , specified here .

[0089] Using the aforementioned After compensating the rudder angles of each steering wheel, the calibration actions are executed again in segments in sequence, allowing the multi-steering wheel chassis to execute "Action 1~Action 6" again. The actual actions 1 and 2 are used for calculation. Since action 1 is a translational forward motion and action 2 is a translational backward motion, the ideal position of action 2 can be calculated based on action 1. Compensation is then calculated based on the ideal and actual positions of action 2, as shown in the attached diagram. Figure 5 As shown.

[0090] Formula 7

[0091] Where L is the ideal trajectory distance (distance of translational motion), D is the distance between the end of the ideal trajectory and the end of the actual trajectory, and D can be positive or negative. The chassis position after the above actions are completed is used as the origin of the coordinate system, and the chassis motion direction is used as the X-axis to establish a right-handed coordinate system. The sign of the projection of D onto the Y-axis of the coordinate system is used as the sign of D. (Appendix) Figure 5 The 'D' in the text is a negative sign.

[0092] Then, similarly, calculate actions 2 and 3. Since action 2 is an open-loop linear backward motion and action 3 is an open-loop linear leftward lateral motion, the ideal position of action 3 can be calculated based on action 2. Compensation is then calculated based on the ideal and actual positions of action 3. As attached Figure 6 As shown. Similarly, it can be calculated that... .

[0093] Step S300

[0094] according to and Construct a steering wheel differential compensator to compensate for the downward steering angle of each steering wheel when the chassis moves.

[0095] Specifically, based on the aforementioned single-action rudder angle compensation optimization model, the rudder angle compensation for each rudder wheel under different actions can be obtained. Based on the aforementioned full-motion rudder angle compensation optimization model, the rudder angle compensation values ​​for all steering wheels under different actions can be obtained: ,and Therefore, the final rudder angle compensation for each steering wheel under each action is:

[0096] .

[0097] Here, the steering wheel i is defined such that the speed of the travel motor is positive when the rudder angle is 0° and the final rudder angle compensation is... When the rudder angle is 90° and the movement is lateral to the left in a straight line, the speed of the travel motor is positive, and the final rudder angle compensation is... When the rudder angle is -90° and the movement is straight to the right, the travel motor speed is positive, and the final rudder angle compensation is... The interpolation table for the i-th steering wheel group when the travel motor speed is positive can be obtained:

[0098] Table 1. Interpolation table for the i-th steering wheel group when the travel motor speed is positive.

[0099]

[0100] Define the steering wheel i as rotating in an open-loop linear reversal at a steering angle of 0°, where the travel motor speed is negative, and the final steering angle compensation is... When the rudder angle is 90° and the movement is lateral to the right in a straight line, the speed of the travel motor is negative, and the final rudder angle compensation is... When the rudder angle is -90° and the movement is to the left in a straight line, the speed of the travel motor is negative, and the final rudder angle compensation is... The interpolation table for the i-th steering wheel group when the travel motor speed is negative can be obtained:

[0101] Table 2 Interpolation table for the i-th steering wheel group when the travel motor speed is negative.

[0102]

[0103] Finally, after calculating the interpolation compensation table for each steering wheel, a steering wheel differential compensator can be constructed to compensate for the downward steering angle of each steering wheel during chassis movement:

[0104] The rudder angle issued is as follows If the travel motor speed is positive, then the formula for calculating the rudder angle compensation is:

[0105] Unit: rad Formula 8

[0106] The rudder angle issued is as follows If the travel motor speed is positive, then the formula for calculating the rudder angle compensation is:

[0107] Unit: rad Formula 9

[0108] The rudder angle issued is as follows If the travel motor speed is negative, then the formula for calculating the rudder angle compensation is:

[0109] Unit: rad Formula 10

[0110] The rudder angle issued is as follows If the travel motor speed is negative, then the formula for calculating the rudder angle compensation is:

[0111] Unit: rad Formula 11

[0112] The final distribution angle after compensation is: .

[0113] Furthermore, although the above example only samples the steering wheel angles at 0°, 90°, and -90°, in practical applications, those skilled in the art can increase the sampling data according to the actual situation to provide more steering wheel angle compensation calibration results. This example does not impose any limitations. Therefore, any other equivalent alternative embodiments proposed based on this example and continuing the inventive concept are within the scope of this invention.

[0114] The following is attached Figure 1 Taking the three-steering wheel chassis model shown as an example, a simulation test is conducted according to the steps described above. This robot chassis has three steering wheel assemblies (a combination of a walking motor and a steering motor). The installation position of the walking motor in the first steering wheel assembly... wheel diameter The installation location of the travel motor for the second steering wheel assembly. wheel diameter The installation location of the travel motor for the third steering wheel assembly. wheel diameter .

[0115] First, control the chassis as follows. Figure 3 The open-loop motion shown is used for calibration data acquisition.

[0116] The actual movement trajectory of the chassis is as follows Figure 7 As shown. The trajectories of actions 1 and 2 do not coincide, the trajectories of actions 3 and 4 do not coincide, the trajectories of actions 5 and 6 do not coincide, the starting direction of action 3 and the ending direction of action 2 are not strictly perpendicular, the starting direction of action 5 and the ending direction of action 4 are not strictly parallel, and the trajectory of each action is an arc.

[0117] The main reason for this phenomenon is the existence of factors such as inaccurate zero position of the steering motor, inaccurate feedback of the motor rudder angle encoder, and gear meshing error, which cause the rudder angle zero position error of the multi-rudder wheel chassis to be inconsistent under different motion actions and steering motor angles.

[0118] - Construct a multi-steering wheel odometer synthesis model

[0119] Based on real-time data collected during chassis movement, such as the rotational speed of the drive motor and the angle of the steering motor, the ideal chassis trajectory can be obtained according to Formula 5. Figure 8As shown. Ideally, the trajectories of actions 1 and 2 coincide, the trajectories of actions 3 and 4 coincide, the trajectories of actions 5 and 6 coincide, the starting direction of action 3 and the ending direction of action 2 are strictly perpendicular, the starting direction of action 5 and the ending direction of action 4 are strictly parallel, and the trajectory of each action is a straight line.

[0120] - Construct an optimization model for rudder angle compensation for a single action

[0121] For action 1: Open-loop linear forward motion. Assume the fixed deviations between the actual and ideal steering angles of the three steering wheels are as follows: After solving the optimization model according to Formula 6, the rudder angle compensation results for the three rudder wheels are obtained as follows: Similarly, the rudder angle compensation results for the other five actions can be obtained respectively:

[0122]

[0123]

[0124]

[0125]

[0126]

[0127] The optimal solution for the optimization variables based on the optimization model is existing knowledge, and the specific solution process will not be elaborated in this example.

[0128] - Construct a full-motion rudder angle compensation optimization model

[0129] Substitute the individual steering wheel angle compensation results obtained above into Formula 4 for compensation, and then execute the appendix again. Figure 3 The calibration action shown can actually be obtained as follows: Figure 9 The actual trajectory shown is compared to Figure 7 The trajectory in Figure 9 The trajectory of each action in the model becomes a straight line. The compensation for the six action angles in the full-action rudder angle compensation optimization model is set as follows: ,in Calculate based on actual action 1 and action 2. According to Formula 7, we can obtain Based on actions 2 and 3, the calculation yields... Based on calculations from actions 3 and 4, we can obtain... Based on calculations from actions 4 and 5, we can obtain... Based on calculations from actions 5 and 6, we can obtain... .

[0130] - Constructing an interpolation compensator

[0131] Finally, the rudder angle compensation for each of the three rudder angles can be calculated:

[0132] Action 1: Steerable angle 0°, open-loop straight forward movement:

[0133] Action 2, rudder angle 0° open-loop straight reverse:

[0134] Action 3, rudder angle 90° open-loop straight leftward lateral movement:

[0135] Action 4, rudder angle 90° open-loop straight rightward lateral movement:

[0136] Action 5, rudder angle -90° open-loop straight right lateral movement:

[0137] Action 6, Rudder angle -90°, open-loop straight left lateral movement:

[0138] The interpolation table for the first steering wheel assembly when the travel motor speed is positive can be obtained:

[0139] Table 3. Interpolation table for the first steering wheel assembly when the travel motor speed is positive.

[0140]

[0141] Interpolation table for the first steering wheel group when the travel motor speed is negative:

[0142] Table 4. Interpolation table for the first steering wheel assembly when the travel motor speed is negative.

[0143]

[0144] The interpolation tables for the second and third steering wheel groups can be given similarly, and will not be listed here.

[0145] - Use interpolation compensator

[0146] After calculating the interpolation compensation table for each steering wheel, the steering angle can be compensated based on the current rudder angle issued by the steering wheel when actually controlling the chassis.

[0147] If the rudder angle issued is 105° The travel motor speed is positive. According to formula 8 for rudder angle compensation, the rudder angle compensation angle is:

[0148]

[0149] The compensated distribution angle is then: .

[0150] On the other hand, corresponding to the above method examples, such as Figure 10 As shown, the present invention also provides a rudder angle compensation calibration system for a multi-rudder robot motion chassis, comprising:

[0151] The storage unit contains a program that implements the steps of the multi-steering wheel robot motion chassis rudder angle compensation calibration method as described above, so that the control unit, data acquisition unit and processing unit can retrieve and execute it as needed.

[0152] The control unit is used to control the segmented execution of calibrated movements by the multi-steering wheel robot's motion chassis. This control unit is typically integrated into the robot chassis.

[0153] The data acquisition unit is used to collect the wheel speed, rudder angle, and chassis positioning posture of each steering wheel motor at each stage. These data acquisition units can be assembled from known sensors, and those skilled in the art can refer to the sensor configurations on existing known steering wheel robots.

[0154] The processing unit is used to calculate the relative attitude changes of the chassis before and after each stage of calibration action based on the known installation position and wheel diameter of each steering wheel, and to determine the corresponding steering angle compensation value. Compensate the rudder angles of each steering wheel; based on the data collected after performing the calibration actions in sequence again, calculate the positional offset between the previous and subsequent calibration actions to determine the compensation value for the rudder angles of all steering wheels in the subsequent calibration action. ;according to and A steering wheel differential compensator is constructed to calculate the compensation value of the steering angle issued by each steering wheel. This processing unit can be integrated into the robot's own hardware or externally handled by a scheduling system or other cloud server system, and the result calculation is completed through data interaction via wired or wireless communication devices.

[0155] On the other hand, corresponding to the above method examples, the present invention also provides a computer-readable storage medium storing a computer program thereon, wherein the computer program, when executed by a processor, implements the steps of the multi-steering wheel robot motion chassis rudder angle compensation calibration method described in the above embodiments.

[0156] In summary, the multi-wheel robot motion chassis rudder angle compensation calibration method and system provided by this invention ingeniously designs a segmented calibration action to collect speed data under each stage of the action, establish a rudder angle compensation mechanism for each rudder under a single action, and perform preliminary rudder angle compensation based on this, and then execute the calibration action again. By comparing the angle changes in the ideal pose and the actual pose changes, a rudder angle compensation mechanism for all rudders is constructed. This fully considers the actual impact of compensating for single and multiple rudders on the accuracy of the chassis when performing motion actions, and solves the problem of insufficient motion control accuracy caused by the deviation between the ideal and actual chassis motion trajectory after rudder angle compensation in existing multi-wheel chassis. This improves the applicability of multi-wheel mobile robots in complex and high-precision scenarios.

[0157] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not exhaustively describe all details, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification. This specification selects and specifically describes these embodiments to better explain the principles and practical applications of the invention, thereby enabling those skilled in the art to better understand and utilize the invention. The present invention is limited only by the claims and their full scope and equivalents. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the invention should be included within the protection scope of the invention.

[0158] Those skilled in the art will understand that, besides implementing the system, apparatus, unit, and its modules provided by this invention in purely computer-readable program code, the same program can be implemented in the form of logic gates, switches, application-specific integrated circuits, programmable logic controllers, and embedded microcontrollers by logically programming the method steps. Therefore, the system, apparatus, and its modules provided by this invention can be considered a hardware component, and the modules included therein for implementing various programs can also be considered structures within the hardware component; alternatively, modules for implementing various functions can be considered both software programs implementing the method and structures within the hardware component.

[0159] The implementation of all or part of the steps in the methods of the above embodiments can be accomplished by a program instructing related hardware. This program is stored in a storage medium and includes several instructions to cause a microcontroller, chip, or processor to execute all or part of the steps of the methods described in the various embodiments of this application. The aforementioned storage medium includes various media capable of storing program code, such as a USB flash drive, a portable hard drive, a read-only memory (ROM), a random access memory (RAM), a magnetic disk, or an optical disk.

[0160] Furthermore, various different implementations of the present invention can be combined arbitrarily, as long as they do not violate the spirit of the present invention, they should also be regarded as the content disclosed in the present invention.

Claims

1. A method for calibrating the rudder angle compensation of a multi-rudder robot's motion chassis, comprising the following steps: The chassis is controlled to perform calibration actions in sequence, and the wheel speed, rudder angle, and chassis positioning posture of each steering wheel i at time n in each stage are collected. Based on the installation position and wheel diameter of each steering wheel, the relative position and attitude changes of the chassis before and after each stage of calibration are calculated to determine the corresponding steering angle compensation value. ; use Compensate the rudder angles of each steering wheel, and then perform the calibration actions in segments again in sequence. Calculate the positional offset between each calibration action to determine the overall rudder angle compensation value for the subsequent calibration actions. ; according to and Construct a steering wheel differential compensator to compensate for the downward steering angle of each steering wheel when the chassis moves.

2. The method according to claim 1, wherein the rudder angle compensation value The calculation steps include: Based on the installation position of each steering wheel, the linear velocity and angular velocity of each steering wheel along the X and Y axes in the vehicle coordinate system are calculated before and after each stage of calibration action to determine the ideal relative posture change of the chassis. ; Based on the collected positioning and pose data, the actual relative pose changes of the chassis are determined before and after each stage of the calibration action. ; Pick and An optimization model is constructed based on the angle change data to solve for the rudder angle compensation value of each rudder wheel when performing the calibration action at each stage. .

3. The method according to claim 1, wherein the total steering wheel rudder angle compensation value The calculation steps include: The calibration motion is decomposed into sequential actions. The ideal trajectory of the subsequent action is determined based on the trajectory of the preceding action. The full rudder wheel angle compensation value for the subsequent action is determined based on the distance between the end points of the ideal and actual trajectories. .

4. The method of claim 1, wherein the method uses The steps for compensating for the rudder angle of each steering wheel include: According to the installation position of each steering wheel wheel diameter Wheel speed , and rudder angle Establish a formula for calculating the linear velocity of the steering wheel, and use... Compensation rudder angle : 。 5. The method according to claim 1, wherein according to and The steps for constructing a steering wheel differential compensator include: Define the sign of the steering wheel's rotational speed when performing each stage of the calibration action, and assign compensation values. and By associating the rudder angle with the corresponding stage calibration action, an interpolation table is established and an interpolation compensator is constructed accordingly.

6. The method according to any one of claims 1 to 5, wherein the calibration action comprises: The steering wheel angle is rotated to 0° in the vehicle coordinate system to perform open-loop straight forward and straight backward movements. The steering wheel angle is rotated to 90° in the vehicle coordinate system to perform an open-loop linear left lateral movement and a linear right lateral movement. The steering wheel angle is rotated to -90° in the vehicle coordinate system to perform open-loop linear rightward and linear leftward movements.

7. A rudder angle compensation calibration system for a multi-rudder robot motion chassis, comprising: The storage unit contains a program that implements the steps of the multi-steering wheel robot motion chassis rudder angle compensation calibration method as described in any one of claims 1 to 6, so that the control unit, data acquisition unit and processing unit can retrieve and execute it as needed. The control unit is used to control the segmented execution of calibrated actions by the motion chassis of the multi-steering wheel robot. The data acquisition unit is used to collect the wheel speed, rudder angle, and chassis positioning posture of each steering wheel at each stage. The processing unit is used to calculate the relative attitude changes of the chassis before and after each stage of calibration action based on the known installation position and wheel diameter of each steering wheel, and to determine the corresponding steering angle compensation value. Compensate the rudder angles of each steering wheel; based on the data collected after performing the calibration actions in sequence again, calculate the positional offset between the previous and subsequent calibration actions to determine the compensation value for the rudder angles of all steering wheels in the subsequent calibration action. ;according to and Construct a steering wheel differential compensator and calculate the compensation value for the steering angle issued by each steering wheel.

8. A computer-readable storage medium having a computer program stored thereon, wherein the computer program, when executed by a processor, implements the steps of the multi-steering wheel robot motion chassis rudder angle compensation calibration method according to any one of claims 1 to 6.

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