Robot Trajectory Control Using Sensor Reliability Feedback
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Solution Overview
Problem
Existing robot control devices struggle to achieve high accuracy and stability in robot operations when using multiple sensors of the same type, especially under disturbances such as changes in environmental light, which can lead to unstable sensor signals and potential system damage.
Innovation Solution
A robot control device that includes a reliability computing unit to assess the reliability of sensor signals based on temporal or spatial changes in feature quantities, a correction command value computing unit to calculate trajectory corrections based on reliability and correction information, and a command value generation unit to produce location commands for the robot based on a target trajectory and trajectory corrections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors of the same type are used for control, then measurement coverage is improved, but system stability deteriorates under disturbances such as environmental light changes
Solution Approach 1:
The patent introduces a reliability evaluation unit as an intermediary that assesses the quality of sensor signals before they are used for control. This mediator evaluates whether sensor signals are reliable based on temporal and spatial changes, and only uses signals that pass the reliability threshold, thus preventing unstable signals from causing system instability while maintaining the benefits of multiple sensors.
Solution Approach 2:
The system implements feedback by continuously monitoring sensor signal reliability and adjusting control actions accordingly. When sensor signals become unreliable due to disturbances, the system detects this through the reliability evaluation unit and modifies its control behavior, creating a closed-loop system that maintains stability while utilizing multiple sensors for improved measurement coverage.
2Reliability
If robot operation speed is reduced to prevent system damage, then system safety is improved, but production efficiency deteriorates
Solution Approach 1:
The patent applies dynamics by making the robot operation speed variable rather than fixed. The speed is dynamically adjusted based on real-time reliability evaluations of sensor signals. When signals are reliable, the robot operates at normal speed for high productivity. When signals become unreliable, the speed is reduced to prevent system damage, thus achieving both safety and efficiency through adaptive speed control.
Solution Approach 2:
The system changes the operational parameter (speed) based on the reliability parameter of sensor signals. By monitoring temporal and spatial changes in sensor data, the system adjusts the speed parameter dynamically - maintaining high speed when conditions are good and reducing speed when disturbances are detected, thereby resolving the contradiction between safety and productivity.
3Measurement precision
If weighted averaging of multiple sensor signals is used, then control accuracy is improved, but vulnerability to simultaneous sensor failure increases
Solution Approach 1:
The patent applies preliminary action by evaluating the reliability of sensor signals before performing weighted averaging. The reliability evaluation unit assesses each sensor signal's quality in advance based on temporal and spatial changes, and only signals that pass the reliability threshold are included in the averaging process. This preliminary filtering prevents simultaneously failed sensors from corrupting the control accuracy while still benefiting from the averaging of reliable signals.
Data Source
AI summary
A robot control device includes: a reliability computing unit that is inputted with a feature quantity obtained from a sensor signal indicating a measurement result obtained by an external sensor installed in a main body of a robot or a surrounding environment of the robot, and computes a reliability for the sensor signal on the basis of a temporal change or a spatial change of the feature quantity; a correction command value computing unit that computes a trajectory correction amount for correcting a trajectory of the robot on the basis of the reliability and correction information calculated on the basis of the feature quantity; and a command value generation unit that generates a location command value for the robot on the basis of a predetermined target trajectory of the robot and the trajectory correction amount.