Robot Arm Teaching via Strain-Gauge Force Estimation
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Solution Overview
Problem
Conventional robot teaching systems face limitations in accurately estimating external forces applied to multiple points on a robot due to the need for multiple sensors, which increases cost and complexity, and restricts intuitive teaching, especially when the robot's posture is near a singular configuration or when the number of joints between the teaching force application point and the fixed part is small.
Innovation Solution
A robot teaching system that utilizes strain gauges attached to the robot arm to measure deformation and estimate external forces without additional sensors, allowing for intuitive and efficient teaching by converting deformation values into moment and torque values to calculate teaching forces and move the robot accordingly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple sensors are attached to measure external forces at multiple points, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent combines multiple measurement functions into a single sensor attachment point. By measuring the reaction force at one location and using dynamic equations to calculate forces at multiple points, the system achieves multi-point force measurement capability without physically attaching multiple sensors, thus reducing device complexity while maintaining measurement precision
Solution Approach 2:
The patent introduces an intermediary calculation method (dynamic equation-based force distribution algorithm) that acts as a mediator between the single sensor measurement and the multiple force estimation points. This intermediary computational approach enables accurate force estimation at multiple locations without requiring physical sensors at each location
2Adaptability or versatility
If additional teaching devices are added to improve teaching flexibility, then adaptability is improved, but device complexity increases
Solution Approach 1:
The patent makes the robot arm itself multi-functional by enabling it to serve both as the manipulator and as the teaching device. The strain sensors integrated into the robot arm allow it to detect teaching forces directly, eliminating the need for separate teaching devices and reducing overall system complexity while improving teaching flexibility
Solution Approach 2:
The robot arm performs self-teaching by using its own structure (with integrated strain sensors) to detect and measure teaching forces applied during the teaching process. This self-service capability eliminates the need for external teaching devices, simplifying the system while enhancing adaptability
3Measurement precision
If strain gauges are attached to multiple links, then external force estimation accuracy is improved, but manufacturing complexity increases
Solution Approach 1:
The patent segments the measurement function across multiple links by attaching strain gauges to different links of the robot arm. This segmentation allows the system to capture deformation information from multiple locations, which is then used to accurately estimate external forces at various points through computational methods, improving measurement precision while keeping each individual sensor attachment simple
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
Enables accurate estimation and application of teaching forces to multiple points, reducing the need for multiple sensors, minimizing posture changes, and enhancing teaching efficiency while maintaining cost-effectiveness.
Implementation Method 1
a plurality of strain gauges respectively coupled to frames of the plurality of links to measure a deformation value of the link that is deformed by the external force
Data Source
AI summary
The present disclosure relates to a robot teaching system, which moves a robot according to an external force applied from the outside so that the robot has a location and posture intended for teaching and then teaches a location and posture of the moved robot, and the robot teaching system comprises: an arm including a plurality of articular shafts and a plurality of links connected by the plurality of articular shafts; a plurality of strain gauges respectively coupled to frames of the plurality of links to measure a deformation value of the link that is deformed by the external force; and a calculating device configured to estimate the external force from the deformation value of the link obtained by the plurality of strain gauges, calculate a teaching force from the external force and move the robot by an operation corresponding to the teaching force.