Segmented Force Sensor for Low-Profile Force and Moment Detection
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Solution Overview
Problem
Existing force sensors are costly and have a high profile, which complicates accurate control of robot arms due to increased distance from the leading end to the tool, necessitating a need for a lower-priced and lower-height sensor solution.
Innovation Solution
An individual force sensor design comprising a first and second sensor body connected by a strain generating body with a connecting body and displacement bodies, utilizing a detecting element to measure elastic deformation, and a Wheatstone bridge circuit for signal output, with components formed to optimize deformation response and minimize height.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a conventional force sensor design is used, then force and moment detection capability is achieved, but the sensor height is large and manufacturing cost is high
Solution Approach 1:
The force sensor is divided into multiple independent sensor bodies (first sensor body, second sensor body, third sensor body) that are arranged separately and connected through strain generating bodies. This segmentation allows each sensor body to be compact while maintaining the overall detection capability, thereby reducing the total height of the sensor assembly.
Solution Approach 2:
The sensor bodies are arranged in a planar configuration (along the first direction) rather than stacking them vertically. The strain generating bodies extend in the first direction to connect the sensor bodies, transforming the vertical height problem into a lateral arrangement solution, thus reducing sensor height while preserving detection functionality.
2Measurement precision
If a conventional force sensor design is used, then force and moment detection capability is achieved, but manufacturing cost is high
Solution Approach 1:
By dividing the force sensor into multiple independent sensor bodies and strain generating bodies, the design allows for standardized mass production of individual components. Each sensor body can be manufactured separately using conventional techniques, and then assembled, which reduces overall manufacturing complexity and cost compared to producing a single integrated sensor unit.
Solution Approach 2:
The invention uses strain generating bodies with specific elastic moduli and geometric parameters (cross-sectional area, length) that can be optimized for cost-effective manufacturing. By carefully selecting material parameters and dimensional parameters of the strain generating bodies, the sensor achieves required performance at lower manufacturing cost.
3Manufacturing precision
If sensor height is reduced, then robot control accuracy is improved, but detection sensitivity may be compromised
Solution Approach 1:
The strain generating bodies are designed with optimized parameters including elastic modulus, cross-sectional area, and length to maintain high detection sensitivity despite the reduced sensor height. By adjusting these parameters, the strain generating bodies can produce sufficient elastic deformation for accurate measurement while keeping the overall sensor compact.
Solution Approach 2:
Multiple sensor bodies are used to detect different components of force and moment. Each sensor body with its associated strain generating body acts as a replication of the detection function for specific measurement directions, ensuring that detection sensitivity is maintained across all measurement axes even with reduced height.
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 design achieves a lower-cost and reduced-height force sensor capable of precise force and moment detection, enhancing robot control accuracy.
Implementation Method 1
a first strain generating body that connects the first individual sensor body and the second individual sensor body and that is elastically deformed by the force or moment acting on the first individual sensor body
Implementation Method 2
the detecting element includes a fixed electrode substrate provided on the second individual sensor body and a displacement electrode substrate provided on the displacement body and opposed to the fixed electrode substrate
Data Source
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AI summary
An individual force sensor according to the present invention includes a first individual sensor body, a second individual sensor body, a first strain generating body that connects the first individual sensor body and the second individual sensor body, and a detecting element that detects displacement caused by elastic deformation of the first strain generating body. The first strain generating body includes a first connecting body extending in a first direction from a first end connected to the first individual sensor body to a second end connected to the second individual sensor body and a displacement body protruding from the first connecting body in a second direction orthogonal to the first direction. The detecting element includes a fixed electrode substrate provided on the second individual sensor body and a displacement electrode substrate provided on the displacement body and opposed to the fixed electrode substrate.