Force Sensor Segmentation for Off-Center Detection Accuracy
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Solution Overview
Problem
Existing force detecting devices for robots, such as those described in JP-A-2015-71214, face challenges in accurately detecting external forces when applied off-center, leading to increased other axis outputs and reduced accuracy in robotic operations.
Innovation Solution
A force detecting device with a first base and a second base, featuring piezoelectric elements and a projecting section, is designed to reduce other axis outputs and enhance detection accuracy by applying forces uniformly across multiple axes, even when external forces are applied off-center, using a configuration that includes a recess on the first base and pressurizing walls to maintain constant pressure on the piezoelectric elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the force sensor uses a flat upper end face with the entire region fixed to the finger unit, then the structure is simple and easy to manufacture, but when an external force is applied to a position deviating from the center axis, the other axis output increases and detection accuracy deteriorates
Solution Approach 1:
The upper end face is divided into a pressure receiving surface (center region) and a fixing surface (peripheral region), allowing different functional zones to be optimized independently for both manufacturing simplicity and detection accuracy
Solution Approach 2:
Different regions of the upper end face are assigned different functions: the center pressure receiving surface maintains flatness for accurate force detection, while the peripheral fixing surface provides attachment functionality, creating local quality differentiation that resolves the contradiction
2Adaptability or versatility
If the contact part of the finger unit deviates from the center axis of the force sensor, then the robot can handle objects at various positions, but the other axis output increases and detection accuracy deteriorates
Solution Approach 1:
By segmenting the upper end face into pressure receiving and fixing surfaces, the system allows the contact point to vary across the pressure receiving surface for handling flexibility, while the fixed peripheral region maintains structural stability and detection accuracy
3Ease of manufacture
If the force sensor is designed with a cylindrical shape and flat upper end face, then the manufacturing is simple, but the detection accuracy deteriorates when external forces are applied off-center
Solution Approach 1:
The cylindrical body maintains manufacturing simplicity while the upper end face introduces local quality differentiation with distinct pressure receiving and fixing surfaces, optimizing both manufacturing ease and detection accuracy
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 improves the detection accuracy of external forces both on and off-center, reducing unnecessary force outputs and enhancing the precision of robotic operations by stabilizing the force detection across various axes.
Implementation Method 1
at least one piezoelectric element supported between the first base and the second base and configured to detect external forces applied to the first base and the second base
Data Source
AI summary
A force detecting device attachable to a robot including an arm includes a first base including a projection having an attachment surface to which an end effector is attachable, a second base attached to the arm, and at least one piezoelectric element supported between the first base and the second base and configured to detect external forces applied to the first base and the second base.