Piezoelectric Sensor Detecting Kinetic Friction for Robot Hand Slipping
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Solution Overview
Problem
Existing piezoelectric sensors struggle to detect slipping events between a gripping target and a robot hand, as the slipping does not significantly change the gripping force, making it difficult for the sensor to differentiate between slipping and stable gripping.
Innovation Solution
A piezoelectric sensor system comprising an elastic body, a piezoelectric element that deforms in response to the elastic body's deformation, and a detector that identifies kinetic frictional force by analyzing variations in the voltage signal due to relative movement between the elastic body and an object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional piezoelectric sensor is used to detect gripping force, then the gripping force can be detected, but slipping events cannot be detected because the gripping force does not significantly change during slipping
Solution Approach 1:
The patent transforms the static pressure detection approach into a dynamic friction force detection approach. By orienting the piezoelectric element to detect frictional force in the direction of potential slipping motion, the system can dynamically detect slipping events as they occur, rather than relying on changes in gripping force magnitude.
Solution Approach 2:
The patent changes the detected parameter from gripping force magnitude to frictional force direction and magnitude. The piezoelectric element is specifically oriented to measure the frictional force component parallel to the contact surface, which changes during slipping events even when the normal gripping force remains constant.
2Measurement precision
If the piezoelectric element is oriented to detect gripping force, then gripping force detection is possible, but kinetic frictional force detection during slipping is not achieved
Solution Approach 1:
The patent applies local quality by orienting the piezoelectric element at a specific angle (preferably 45 degrees or parallel to the contact surface) to selectively detect frictional force in the direction of potential slipping. This localized orientation optimization enables friction detection without requiring complex multi-element arrays.
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 effectively detects kinetic frictional force and slipping events by distinguishing between static and kinetic frictional forces, enabling the robot hand to prevent object dropping and maintain stable grip.
Implementation Method 1
a piezoelectric element which is disposed at a position where the piezoelectric element has contact with the elastic body, and which is configured to output a voltage signal when deforming in accordance with a deformation of the elastic body
Data Source
AI summary
A piezoelectric sensor includes an elastic body, a piezoelectric element which is disposed at a position where the piezoelectric element has contact with the elastic body, and which is configured to output a voltage signal when deforming in accordance with a deformation of the elastic body, and a detector configured to detect the voltage signal output from the piezoelectric element, wherein the detector detects kinetic frictional force generated between the object and the elastic body based on a variation in the voltage signal due to the relative movement of the object to the elastic body.