Parallel Link Robot Calibration Fixture with Dial Gauges
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Solution Overview
Problem
In δ-type parallel link robots, excessive driving of arms during position calibration can lead to excessive abutting force between reference pins and origin pins, potentially causing damage to the robot.
Innovation Solution
The implementation of a calibration use fixture with dial gauges that measure the distance between reference and moving flat surfaces, allowing for precise calibration without over-rotation and reducing the risk of damage by allowing the drive links to rotate past the reference positions while maintaining control through predetermined measurement positions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the arms are driven to make the reference pins abut against the origin pins for calibration, then the positional precision of the operating head is improved, but the arms are liable to be mistakenly driven too much causing excessive abutting force and potential damage
Solution Approach 1:
The patent employs dial gauges as measuring devices that provide real-time feedback on the position of the link parts during calibration. The dial gauges are attached to the base part and measure the displacement of the link parts as they rotate, allowing the operator to precisely determine when the reference position is reached and stop the rotation, thereby preventing over-rotation and excessive abutting force between the reference pins and origin pins.
Solution Approach 2:
The patent replaces the purely mechanical abutting method (where operators visually estimate or manually feel when pins contact) with a measurement-based system using dial gauges. This substitution of mechanical estimation with precise measurement allows for accurate positioning without relying on operator judgment, eliminating the risk of mistaken over-driving while maintaining the mechanical pin-abutting calibration mechanism.
2Reliability
If the arms are driven carefully to avoid over-rotation, then damage risk is reduced, but the calibration process becomes more time-consuming and less efficient
Solution Approach 1:
The dial gauges provide continuous visual feedback during the rotation of link parts, allowing operators to quickly and accurately identify the reference position without cautious trial-and-error movements. The clear numerical indication from the dial gauges enables rapid positioning, maintaining high calibration efficiency while ensuring precise stopping at the reference position to prevent over-rotation and damage.
3Ease of operation
If traditional pin-abutting method is used for calibration, then the calibration process is simple, but it is difficult to detect the precise reference position and avoid over-rotation
Solution Approach 1:
The patent replaces the imprecise mechanical pin-abutting detection method with dial gauge measurement systems. The dial gauges provide precise numerical measurement of the link part positions, allowing operators to accurately identify the reference position where the moving flat surface aligns with the reference flat surface. This maintains operational simplicity while dramatically improving measurement precision compared to visual or tactile estimation methods.
Data Source
AI summary
A parallel link robot includes a base part having actuators, a part movable with respect to the base part, link parts with first ends linked with the plurality of actuators rotatably around rotary shafts with respect to the base part and with other ends linked with the moving part, and fixtures attached to the base part to measure rotational positions of the link parts. The base part has reference flat surfaces, and the link parts have moving flat surfaces extended in parallel with respect to the rotary shafts. Positional relationships between the moving flat surfaces and the reference flat surfaces become predetermined positional relationships when the link parts rotate to reference positions for calibration of position. The fixtures have measuring devices arranged at measurement positions with known positional relationships with respect to the reference flat surfaces.