Robot Force Control for Fitting Pass-Fail Detection
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Solution Overview
Problem
Existing robots face challenges in accurately determining the success of fitting work due to reliance on position control rather than force control, leading to difficulties in comparing force waveforms and storing large amounts of time-series data, which results in inefficient and inaccurate insertion processes.
Innovation Solution
A control device that incorporates a force control section to manage force control based on detected forces and a determining section to assess the success of fitting work by identifying a decrease in force by a specific value, allowing for easy and accurate determination of pass/fail outcomes, with optional first and second force control modes and consideration of elastic sections in engaging components.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If waveform comparison method is used to determine fitting success, then determination accuracy is improved, but data storage requirement increases enormously
Solution Approach 1:
The patent extracts only the essential feature for fitting success determination - the force decrease portion - from the complete force waveform. Instead of storing and comparing entire time-series force data, the system identifies and evaluates only the critical moment when force decreases, thereby determining fitting success without enormous data storage requirements
Solution Approach 2:
The patent segments the force waveform into distinct portions, specifically identifying the force decrease portion as the key indicator of successful fitting. By dividing the continuous waveform into meaningful segments and focusing only on the relevant segment, the system achieves accurate determination without processing or storing the entire waveform dataset
2Ease of operation
If position control is used for insertion work, then control simplicity is improved, but fitting success rate deteriorates when target position deviation occurs
Solution Approach 1:
The patent introduces force feedback during the insertion process. By monitoring the force waveform in real-time and identifying the characteristic force decrease portion, the system provides feedback on whether fitting is successful. This feedback mechanism maintains control simplicity while significantly improving fitting success rate, as the system can detect successful fitting even when position deviations occur
3Reliability
If force control is implemented for insertion work, then fitting success rate is improved, but control complexity increases
Solution Approach 1:
The patent applies partial force control by implementing force control only during the critical insertion phase when fitting occurs, rather than throughout the entire robot operation. The system uses position control for movement and switching, then transitions to force control specifically for detecting the force decrease portion that indicates successful fitting. This partial application of force control improves fitting success rate while minimizing the increase in control system complexity
Data Source
AI summary
A control device comprising a processor that is configured to execute computer-executable instructions so as to control a robot, wherein the processor is configured to: control a robot with force control on the basis of a force detected by a force detecting device, determine pass/fail of a result of fitting work in which the robot holds an object and fits the object in an object to be fit, control the robot with the force control in the fitting work, and determine the pass/fail on the basis of whether a portion where the force detected by the force detecting device decreases by a first value or more is present in the fitting work.