Multi-DOF Robot Kinematics Calibration Without External Sensors
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Solution Overview
Problem
Existing kinematics calibration methods for robots with multiple degrees of freedom require external sensors, leading to increased measurement errors, setup complexity, and high costs.
Innovation Solution
A method and system that locks part of the robot's degrees of freedom, allowing for data collection on joint angles and actual motion, calculates theoretical motion, and updates initial kinematics parameters to achieve accurate calibration without external sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If external sensors (laser trackers, dial gauges, pull-string devices) are used to measure robot motion for kinematics calibration, then measurement capability is provided, but measurement errors increase, setup complexity increases, and costs increase
Solution Approach 1:
The robot system performs self-calibration by utilizing its own motion data and internal sensors. The control system calculates theoretical motion based on joint angles and compares it with actual motion measurements, enabling the system to self-diagnose and self-correct kinematic parameters without requiring external measurement equipment or operators.
Solution Approach 2:
The invention extracts and eliminates the dependency on external sensors from the calibration process. By removing laser trackers, dial gauges, and pull-string devices, the system achieves calibration using only its built-in sensing capabilities and computational algorithms, thereby reducing setup complexity and external dependencies.
2Measurement precision
If external sensors are used for kinematics calibration, then motion measurement is enabled, but costs increase
Solution Approach 1:
The robot system performs self-calibration by utilizing its own motion data and internal sensors. The control system calculates theoretical motion based on joint angles and compares it with actual motion measurements, enabling the system to self-diagnose and self-correct kinematic parameters without requiring external measurement equipment or operators.
Solution Approach 2:
The invention replaces expensive external sensors with the robot's existing, less costly internal sensing capabilities. By using already-installed joint sensors and onboard computation, the system achieves calibration functionality without investing in additional expensive measurement equipment.
3Adaptability or versatility
If multiple degrees of freedom are fully utilized for robot operation, then operational flexibility is achieved, but calibration complexity increases
Solution Approach 1:
The calibration process is segmented into independent calibration tasks for different degrees of freedom. The control system can selectively lock certain joints and calibrate specific degrees of freedom independently, allowing systematic calibration of complex multi-DOF robots without requiring all joints to be calibrated simultaneously, thereby reducing overall calibration complexity.
Solution Approach 2:
The calibration system dynamically adjusts the robot's configuration by locking and unlocking different joints based on calibration requirements. This dynamic reconfiguration allows the system to simplify the calibration process for each specific degree of freedom while maintaining the robot's full operational flexibility after calibration is complete.
Data Source
AI summary
The present disclosure relates to a kinematics calibration method for a robot with multiple degrees of freedom. The robot includes a base, an end effector, and a plurality of links connected by joints. The method includes locking part of the multiple degrees of freedom by limiting the base and the end effector impose a limitation of degree of freedom; moving the robot to perform a first movement and accordingly obtaining a first set of data associated with joint angles and a first actual motion of the end effector; calculating a first theoretical motion of the end effector based on the first set of data and initial kinematics parameters; and updating the initial kinematics parameters of the robot to obtain a first set of updated kinematics parameters based on the first theoretical motion and the first actual motion.