Piezoelectric Sensor for Robot Hand Force Direction Detection
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Solution Overview
Problem
Existing piezoelectric sensors in robot hands cannot distinguish between compressive and thrust forces, leading to difficulties in determining whether an object is being gripped or lifted, which affects the control of robotic gripping devices.
Innovation Solution
A piezoelectric sensor design featuring an elastic body with a regulatory section and a piezoelectric element that outputs voltage signals varying with deformation direction, allowing for the differentiation of forces applied in multiple directions, including upward, downward, and pressing forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional piezoelectric sensor with an intermediate layer is used, then the sensor can detect pressure through electricity generation, but it cannot distinguish between different deformation modes (compressive force vs. thrust force)
Solution Approach 1:
The sensor is divided into multiple piezoelectric elements arranged in specific patterns (e.g., radial arrangement around a central axis). Each element detects deformation in its specific direction, and by segmenting the detection function across multiple elements, the system can distinguish between different deformation modes such as compressive force (all elements compressed uniformly) and thrust force (central element compressed while outer elements experience different stress)
Solution Approach 2:
Different regions of the sensor have different functional properties. The central region and outer regions are designed with different piezoelectric element configurations to detect different types of forces. The regulatory section creates localized deformation zones that enable direction-specific detection, allowing the sensor to differentiate between forces applied at different locations and angles
2Measurement precision
If the intermediate layer deforms under various forces, then electricity is generated, but the sensor cannot differentiate between the direction of the applied force
Solution Approach 1:
The sensor transitions from detecting only the magnitude of force (one-dimensional) to detecting both magnitude and direction (multi-dimensional). This is achieved by arranging piezoelectric elements in spatial patterns (radial, circumferential, or at different angles) so that the combination of signals from multiple elements provides directional information, effectively adding angular/directional dimensions to the detection capability
3Ease of manufacture
If a simple piezoelectric structure is used, then the device is easy to manufacture, but it lacks the capability to detect multiple deformation modes
Solution Approach 1:
The sensor design integrates multiple detection functions into a single device structure. The same piezoelectric element array can detect compressive forces, thrust forces, and potentially shear forces by analyzing the pattern of deformation across the elements. This multi-functional approach allows the sensor to perform various detection tasks without requiring multiple separate sensors, maintaining ease of manufacture while enhancing versatility
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 detection of force directions and magnitudes, enhancing the robotic hand's ability to distinguish between gripping, lifting, and pressing states, thereby improving operational control and convenience.
Implementation Method 1
a piezoelectric element which is partially fixed to the regulatory section, and which deforms in accordance with the deformation of the elastic body, wherein the piezoelectric element outputs a voltage signal which increases and decreases from the reference voltage in accordance with a direction of the deformation
Data Source
AI summary
A piezoelectric sensor includes an elastic body having a first surface, a regulatory section which is disposed at a position where the regulatory section faces the first surface of the elastic body, and which is configured to limit a deformation of the elastic body, and a first piezoelectric element which is partially fixed to the regulatory section, and which deforms in accordance with the deformation of the elastic body, wherein the first piezoelectric element outputs a voltage signal which increases and decreases from a reference voltage in accordance with a direction of the deformation.