Omnidirectional Wheel Calibration for Yaw Deviation Correction
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Solution Overview
Problem
The moving direction of a moving body with omnidirectional wheels is prone to deviation due to individual differences in electric motors, transmission mechanisms, and contact states between drive disks and the main wheel, leading to inaccuracies in directional control.
Innovation Solution
A calibration method that involves creating rotational speed command values for the electric motors, measuring yaw angle changes, and calculating correction values based on data sets to adjust the rotational speed command values, ensuring precise directional control by repeating the process multiple times to account for variations in motor rotations and yaw angles.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If rotational speed command values are created for four electric motors to control moving direction, then the moving body can perform translational and pivotal movements, but individual differences in each electric motor, transmission mechanism, and contact state cause deviation in moving direction
Solution Approach 1:
The patent performs preliminary calibration measurements before actual operation. Multiple measurement values are collected by executing predetermined movements (linear translation and ultra-pivotal turn) to establish correction values that compensate for individual differences in motors and transmission mechanisms, thereby improving directional accuracy before normal operation begins
Solution Approach 2:
The patent implements a feedback mechanism where actual moving direction measurements are compared with commanded directions. Correction values are calculated based on the difference between measured yaw angle changes and expected values, then applied to adjust rotational speed commands, creating a closed-loop system that continuously improves directional precision
2Measurement precision
If calibration measurements are performed multiple times to obtain accurate correction values, then directional accuracy is improved, but the calibration process time increases
Solution Approach 1:
The patent performs a fixed number of calibration measurements (five times) which is sufficient to achieve adequate accuracy without excessive time consumption. This partial action approach balances measurement precision with time efficiency, avoiding both insufficient calibration and unnecessarily lengthy calibration processes
Solution Approach 2:
The patent changes the calibration parameters by performing measurements at different operating conditions (linear translation and ultra-pivotal turn movements). By varying the movement types and collecting data across different parameter ranges, the system obtains comprehensive correction values that are accurate across the full operating range while maintaining efficient calibration time
Data Source
AI summary
A calibration method for a moving body, which includes a pair of left and right omnidirectional wheels, includes: a first step of creating a rotational speed command value for four electric motors such that the moving body performs a linear translational movement or an ultra-pivotal turn; a second step of driving each motor based on the command value to move the moving body; a third step of obtaining a total number of rotations of each motor until the movement of the moving body is completed; a fourth step of measuring an yaw angle change amount of the moving body as it moves; a fifth step of repeating the first to fourth steps at least three times to obtain three or more data sets including the total number of rotations of each motor and the yaw angle change amount; and a sixth step of calculating each correction value based on the data sets.