Laser-Tracked Cable Robot Positioning for Large-Volume Accuracy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing cable-driven robots face challenges in maintaining precise position control and stability over large volumes due to limitations in positional accuracy, axis non-squareness, scaling issues, and thermal effects, with existing solutions either sacrificing accuracy or increasing complexity and cost.
Innovation Solution
A light beam position measurement system using a cooperative target and laser tracker to accurately control the end effector's position in real-time, correcting for errors and maintaining accuracy in the tens or hundreds of microns, enabling operation over large volumes with a single coordinate system.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of stationary object
If the size of the robot is increased to expand working volume, then the working volume is improved, but the structural complexity and difficulty to transport increase due to the need for increased stiffness
Solution Approach 1:
The patent replaces the traditional mechanical rigid structure with a cable-driven system that uses flexible cables instead of stiff mechanical components. This substitution allows the robot to achieve large working volumes without the structural complexity and transport difficulties associated with rigid frameworks, as the cable system can be more compact and reconfigurable.
2Device complexity
If individual measurements of each degree of freedom are used to control position, then the measurement system is simplified, but the position accuracy is lost due to structural flexibility
Solution Approach 1:
The patent implements a feedback mechanism where the actual position of the end effector is continuously measured and compared to the desired position. The system then adjusts the cable lengths based on this feedback to compensate for structural flexibility and achieve high position accuracy, resolving the contradiction between simple measurement and accurate control.
3Volume of stationary object
If existing cable robot solutions are used to operate over large volumes, then the working volume is improved, but the positional accuracy is sacrificed
Solution Approach 1:
The patent employs dynamic control of the cable lengths in real-time to maintain high positional accuracy across large working volumes. By continuously adjusting the cable tensions and lengths based on feedback from position sensors, the system compensates for the flexibility inherent in cable-driven mechanisms, achieving both large volume coverage and precise positioning.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The system achieves precise position control and stability over large volumes, allowing for new applications and reducing the complexity and cost associated with previous solutions, while maintaining high accuracy and adaptability to environmental conditions.
Implementation Method 1
a light beam measurement device that emits a light beam to measure a position of a cooperative target
Implementation Method 2
a cooperative target that reflects the light beam back to the measurement device
Data Source
AI summary
A light-based measurement system is capable of directing a light beam to a cooperative target used in conjunction with a cable robot to accurately control the position of the end effector within a large volume working environment defined by a single coordinate system. By measuring the end effector while the device is in operation, the cable robot control system can be adjusted in real time to correct for errors that are introduced through the design of the robot itself providing accuracy in the tens or hundreds of micron range. A coordination processor runs control software that communicates with both the laser tracker and the cable robot. An action plan file is loaded by the software that defines the coordinate system of the working volume, the locations where actions need to be performed by the cable robot, and the actions to be taken.