Piezoelectric Component Transducer for Torque Sensing
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Solution Overview
Problem
Existing force and torque sensors, particularly in automation technology and robotics, face challenges in accurately sensing forces and torques in all three Cartesian coordinates with existing piezoelectric crystal material-based transducers, which are limited in their ability to detect torque components due to the sum of electric polarization charges from opposing force components being zero.
Innovation Solution
A component transducer using piezoelectric crystal material with element segments and sensing electrodes arranged to separately sense force components of a pair with opposite directions of action, allowing direct sensing of torque components by spacing element and electrode segments to receive and sum electric polarization charges proportionally to the torque.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If piezoelectric crystal material is used to sense force components, then measurement precision and dynamic measuring range are improved, but the ability to directly sense torque components deteriorates because the sum of electric polarization charges from opposing force components is zero
Solution Approach 1:
The piezoelectric element is divided into multiple segments (first and second segments) with opposite polarization directions. Each segment independently senses force components, allowing the transducer to detect torque by measuring the difference in polarization charges between segments rather than their sum, which would be zero for opposing forces.
Solution Approach 2:
The invention introduces asymmetric polarization directions in adjacent piezoelectric segments. While traditional piezoelectric transducers use uniform polarization, this invention employs alternating polarization directions (e.g., +z and -z directions) in neighboring segments, enabling torque detection through differential measurement of electric charges.
2Adaptability or versatility
If multiple three-component transducers are arranged in a rectangle to sense all force and torque components, then torque components can be sensed, but the overall dimensions and device complexity increase significantly
Solution Approach 1:
The invention merges force sensing and torque sensing capabilities into a single component transducer structure. By arranging piezoelectric segments with alternating polarization directions and configuring electrodes to collect charges differentially, the transducer simultaneously measures both force components and torque components without requiring multiple separate transducers.
Solution Approach 2:
The component transducer is designed to perform multiple functions: it senses all three force components (Fx, Fy, Fz) and all three torque components (Mx, My, Mz) using a single integrated structure. This multi-functional design eliminates the need for multiple specialized transducers while maintaining measurement accuracy.
3Ease of manufacture
If a single component transducer is used for each force component, then manufacturing cost and device complexity are reduced, but the ability to sense torque components is lost
Solution Approach 1:
The invention adds a dimensional aspect to the piezoelectric element configuration by introducing alternating polarization directions in adjacent segments. This dimensional change in the polarization arrangement enables torque sensing capability in what would otherwise be a simple force-sensing element, without increasing overall structural complexity.
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 the detection of torque components with reduced structural dimensions, enhanced robustness, and cost-effectiveness, while maintaining high sensitivity and dynamic measuring range, addressing the limitations of prior art in sensing multiple force and torque components.
Implementation Method 1
an element made of piezoelectric crystal material which defines element surfaces on which a force component acts and generates electric polarization charges
Data Source
AI summary
The invention relates to a component transducer (20) for sensing a torque component (Mx, My, Mz); wherein an element (21) made of piezoelectric crystal material comprises element surfaces; wherein a force component (Fx, Fy, Fz) produces electric polarization charges on the element surfaces; and wherein the torque component (Mx, My, Mz) to be sensed consists of at least one pair having force components (+Fx, −Fx; +Fy, −Fy; +Fz, −Fz) wherein said force components (+Fx, −Fx; +Fy, −Fy; +Fz, −Fz) of a pair have the same axis of action and opposite directions of action. The component transducer (20) receives the force components (+Fx, −Fx; +Fy, −Fy; +Fz, −Fz) of a pair separately.