Robot Control Device for Tracking Randomly Moving Objects
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Solution Overview
Problem
Conventional robot arm control systems using visual servoing face challenges in accurately tracking objects with random movements, especially when feature points are obstructed or not detected frequently, leading to inaccuracies and potential singular point issues.
Innovation Solution
A robot control device with a feature-point detecting unit, a position/orientation calculating unit that updates equations of motion, and a robot-arm-movement control unit that generates trajectories and avoids singular points, allowing the robot arm to follow objects with high accuracy by weighting feature points based on detection frequency and avoiding singularities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If visual servoing is used to control the robot arm to follow the object, then the robot arm can track the object's position and orientation, but tracking accuracy deteriorates when feature points are obstructed or not detected frequently
Solution Approach 1:
The system dynamically changes the parameters of the equations of motion (mass, damping coefficient, stiffness) based on detection frequency and reliability metrics. When feature points are frequently undetected or obstructed, the system adjusts these parameters to maintain accurate position and orientation calculation, thereby resolving the contradiction between tracking accuracy and detection reliability
Solution Approach 2:
The system implements feedback mechanisms by continuously monitoring detection frequency and reliability of feature points. This feedback information is used to adaptively update the equations of motion parameters, ensuring that tracking accuracy is maintained even when detection reliability varies due to obstructions or frequent undetected feature points
2Productivity
If the robot arm follows the object with high speed and large acceleration, then productivity is improved, but singular point issues and operational instability occur
Solution Approach 1:
The system employs dynamic equations of motion that adapt to the robot arm's movement state. By continuously updating the equations based on current position, velocity, and acceleration, the system can handle high-speed tracking while avoiding singular points through adaptive parameter adjustment, thus resolving the contradiction between productivity and operational stability
Solution Approach 2:
The system performs preliminary calculations of the equations of motion and predicts potential singular points before the robot arm reaches them. By preparing alternative trajectories or adjusting parameters in advance, the system prevents operational instability while maintaining high tracking speed, addressing the contradiction between productivity and reliability
3Measurement precision
If multiple feature points are used to calculate object position and orientation, then measurement precision is improved, but system complexity increases due to continuous updating of equations of motion
Solution Approach 1:
The system manages complexity by dynamically adjusting the parameters of the equations of motion based on the actual number of detected feature points and their reliability. This adaptive approach allows the system to use multiple feature points for high precision when available, while simplifying the model when fewer points are detected, thus resolving the contradiction between measurement precision and system complexity
Solution Approach 2:
The system applies different levels of complexity to different parts of the calculation process. High-precision calculations using multiple feature points are performed only when sufficient reliable data is available, while simplified models are used elsewhere, optimizing the balance between measurement precision and control system complexity
Data Source
AI summary
A robot control device includes a feature-point detecting unit that detects, from an image of an object acquired by a visual sensor, the positions of a plurality of feature points on the object in a predetermined cycle; a position/orientation calculating unit that updates, in the predetermined cycle, respective equations of motion of the plurality of feature points on the basis of the detected positions of the plurality of feature points and that calculates the position or orientation of the object on the basis of the detected positions of the plurality of feature points calculated from the updated equations of motion; and a robot-arm-movement control unit that controls the movement of a robot arm so as to follow the object, on the basis of the calculated position or orientation of the object.