Force Detection Apparatus With Non-Uniform Thickness Member
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Solution Overview
Problem
Existing force detection apparatuses in industrial robots face challenges in achieving uniform contact conditions between sensor devices and end effectors, leading to reduced detection accuracy and increased risk of piezoelectric material breakage due to nonuniform contact pressures.
Innovation Solution
The force detection apparatus incorporates an adjustment part with a shorter length than the main contact part, featuring concave or convex shapes and thickness variations to ensure uniform contact pressure, and includes a center pressurization member to reduce stress concentration, thereby improving detection accuracy and yield strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If pressurization members are provided in the outer peripheral portion to apply predetermined pressurization to the sensor device, then the sensor device is securely fastened, but nonuniform contact pressure is caused due to bending of the first member or second member
Solution Approach 1:
The first member is designed with non-uniform thickness, creating a thin portion at the outer peripheral area and a thick portion at the central area. This local variation in thickness allows the thin portion to be more flexible and accommodate pressurization without causing bending, while the thick portion maintains structural integrity and ensures uniform contact pressure distribution across the sensor device.
2Stability of the object's composition
If the first member is made rigid to maintain structural stability, then the overall structure is stable, but contact pressure becomes nonuniform due to bending under pressurization
Solution Approach 1:
The first member incorporates a thickness gradient with a thin portion at the periphery and a thick portion at the center. The thin peripheral portion provides flexibility to prevent bending under pressurization, while the thick central portion maintains structural stability, thus resolving the contradiction between rigidity and contact uniformity.
3Adaptability or versatility
If multiple piezoelectric materials are used to detect forces in different directions, then detection capability is enhanced, but the risk of breakage increases due to nonuniform contact conditions
Solution Approach 1:
The non-uniform thickness design of the first member ensures uniform contact pressure distribution across all piezoelectric materials regardless of their position or orientation. This eliminates stress concentration and reduces the risk of breakage while maintaining the enhanced detection capability provided by multiple piezoelectric materials arranged to detect forces in different directions.
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
This configuration achieves higher accuracy in external force detection and enhances the durability of the force detection element by ensuring uniform contact pressure across the sensor device, reducing the likelihood of breakage and improving mechanical strength.
Implementation Method 1
a sensor device placed between the first member and the second member and including a force detection element having at least one piezoelectric element that outputs a signal according to an external force
Data Source
AI summary
A force detection apparatus includes a first member, a second member placed to be opposed to the first member, a sensor device placed between the first member and the second member and including a force detection element having at a piezoelectric element that outputs a signal according to an external force, and a pressurization bolt provided in an outer periphery of the sensor device in a plan view as seen from a direction in which the first member and the second member overlap and pressurizing the sensor device, wherein the first member has a groove which is between the sensor device and the pressurization bolt in the plan view.