Robot Arm Strain Sensor Contact Detection
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Solution Overview
Problem
Existing robot systems face challenges in detecting light or momentary contacts with high precision due to late response times of force detectors, which affects their functionality and ability to avoid excessive loads on robots or objects around them.
Innovation Solution
A robot system equipped with a robot arm, strain sensors having a piezoelectric body with a natural frequency higher than the structural material, and a control unit that uses high-pass filters and comparison units to quickly detect abnormal vibrations or impacts, allowing for precise torque control and improved responsiveness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a force detector is provided in the robot arm to detect external force, then the robot can detect contact and stop operation or move to reduce external force effect, but the response of the force detector is late which prevents detection of light or momentary touch with high precision
Solution Approach 1:
The patent replaces the conventional force detector with strain gauges that directly measure strain on the robot arm structure. This substitution enables detection of light or momentary contacts with high precision and fast response, overcoming the latency issue of traditional force detectors while maintaining reliable contact detection capability
Solution Approach 2:
The patent uses strain gauges which are thin film sensors attached to the robot arm structure. These thin film sensors can detect subtle deformations and strains caused by external forces, enabling precise detection of light contacts that would be missed by conventional force detectors
2Productivity
If the robot operates at high speed to improve productivity, then output per unit time increases, but the ability to detect and respond to external contacts with high precision deteriorates
Solution Approach 1:
The patent implements preliminary detection of external forces through strain gauges that continuously monitor strain on the robot arm. By detecting contacts before they become significant loads, the system can respond appropriately even during high-speed operations, maintaining both productivity and detection precision
Solution Approach 2:
The patent uses feedback from strain gauge measurements to continuously adjust robot operation. The control unit processes strain data in real-time and modifies operation accordingly, enabling high-speed operation while maintaining precise contact detection and response capability
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
Enhances the robot's ability to detect and respond to contacts with high precision, improving its functionality by enabling timely adjustments to avoid excessive loads and ensuring reliable operation.
Implementation Method 1
a sensor unit that detects an external force applied to at least one of the robot arm and the actuators
Data Source
AI summary
A robot system includes a robot arm, one or more actuators that are provided in the robot arm to drive the robot arm, a sensor unit that detects an external force applied to at least one of the robot arm and the actuators, and a controller that controls an operation of each of the actuators and limits a torque instruction value for each of the actuators on the basis of a detection result of the sensor unit.