Arm Type 3D Measuring Apparatus Deflection Correction
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Solution Overview
Problem
Conventional arm type three-dimensional measuring apparatuses are unable to accurately detect and correct deflection in the axis of a multi-jointed arm mechanism during measurement, limiting their ability to maintain high accuracy when the attitude of the mechanism changes.
Innovation Solution
Incorporating six-axis force sensors in each axis of the multi-jointed arm mechanism to detect forces and torques, and using a processing part to compute deflection amounts and probe positions based on these sensor outputs, with all links made of carbon fiber to minimize deflection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If strain gauges are used to detect deflection in the link, then deflection correction is possible, but deflection in the axis cannot be detected
Solution Approach 1:
The patent replaces the conventional strain gauge-based mechanical detection system with a six-axis force sensor that uses force and torque measurements to detect deflection. This substitution enables detection of deflection in the axis by measuring forces and torques in three-dimensional space, thereby expanding detection coverage from only link deflection to include axis deflection as well.
2Measurement precision
If a six-axis force sensor is used to detect forces and torques, then deflection in the axis can be detected, but device complexity increases
Solution Approach 1:
The six-axis force sensor performs multiple functions simultaneously: it detects forces in three directions and torques in three directions, enabling comprehensive detection of deflection in the axis. This multi-functional sensor replaces what would otherwise require multiple separate detection systems, achieving high measurement precision while managing device complexity through functional integration.
3Manufacturing precision
If all links are made of carbon fiber to minimize deflection, then measurement accuracy improves, but manufacturing complexity increases
Solution Approach 1:
The patent employs carbon fiber composite material for all links in the multi-jointed arm mechanism. This composite material provides high stiffness-to-weight ratio, minimizing deflection of the links during measurement operations. The use of carbon fiber achieves superior positional accuracy (29) despite increased manufacturing complexity (32), as the material properties directly address the deflection issue.
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 high-accuracy measurement of workpieces even when the attitude of the multi-jointed arm mechanism changes, by accurately detecting and correcting deflection in each axis, thereby improving positional accuracy.
Implementation Method 1
a sensor which is formed in each axis of the multi-jointed arm mechanism and detects at least a force in one predetermined direction and torques in two predetermined axial directions
Implementation Method 2
the processing part computes a deflection amount in each axis of the multi-jointed arm mechanism based on an output of the sensor
Data Source
AI summary
An arm type three-dimensional measuring apparatus includes: a multi-jointed arm mechanism including a probe in a distal end; a processing part for computing a position of the probe, the probe being manually moved; a sensor which is formed in each axis of the multi-jointed arm mechanism and detects at least a force in one predetermined direction and torques in two predetermined axial directions generated in an attitude state of the multi-jointed arm mechanism, wherein the processing part computes a deflection amount in each axis of the multi-jointed arm mechanism based on an output of the sensor and sequentially computes a position of the probe based on the deflection amount.