Robot Tool Alignment Using Guide Moment Sensing
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Solution Overview
Problem
Existing screwing and inspection robots face challenges in accurately aligning screws or gauges with screw holes due to slight shifts in position and angle of the screw mating surface, leading to misalignment and failure in tightening or inspection.
Innovation Solution
A robot tool equipped with a shaft member, motor, guide, and force sensor that allows for precise alignment by detecting moments applied from the screw mating surface, enabling the shaft member to be set orthogonal to the surface and aligning with the screw hole using a force sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If teaching operation is performed to align screw hole and screw, then positioning accuracy is improved, but the system becomes sensitive to slight shifts in position and angle of screw mating surface
Solution Approach 1:
The guide tip automatically adjusts its angle relative to the screw mating surface by utilizing the moment force applied during contact. The force sensor detects this moment and feeds back to the robot controller, which adjusts the guide tip's orientation in real-time, enabling the system to self-align without requiring precise pre-teaching of angle variations.
Solution Approach 2:
The system dynamically changes the orientation parameter of the guide tip based on detected moment forces. By continuously adjusting the angle between the guide tip and screw mating surface according to real-time force feedback, the system adapts to position and angle shifts that occur during operation.
2Reliability
If force sensor is used to detect moment applied from screw mating surface, then alignment robustness is improved, but device complexity increases
Solution Approach 1:
The force sensor serves multiple functions: it detects both the contact force between the guide tip and screw mating surface, and simultaneously measures the moment applied during this contact. This multi-functional use of a single sensor reduces overall system complexity compared to using separate sensors for force and moment detection.
Solution Approach 2:
The force sensor acts as an intermediary element between the guide tip and the robot arm. It mediates the mechanical interaction by converting physical contact forces and moments into electrical signals that the robot controller can process, simplifying the control system's task of managing complex force interactions.
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 tool ensures accurate alignment of screws or gauges with screw holes by reducing moments applied from the mating surface to nearly zero, allowing for successful fitting and tightening operations even with slight shifts in surface angles.
Implementation Method 1
a force sensor configured to detect a moment applied from the screw mating surface to the guide when part of the tip of the guide is brought into contact with the screw mating surface
Data Source
AI summary
Provided is a robot tool capable of aligning a screw or a gauge with a screw hole even if a position and angle of a screw mating surface are slightly shifted. A robot tool includes: a shaft member provided with, at at least one end thereof, a gauge that inspects a diameter of a screw hole or a bit that tightens and loosens a screw; a motor accommodating, in a cylindrical motor shaft thereof, the shaft member so that the shaft member is raisable and lowerable; a tubular guide that is disposed so as to enable the shaft member to be inserted thereinto and that has a tip to be brought into contact with a screw mating surface; and a force sensor configured to detect a moment applied from the screw mating surface to the guide when part of the tip of the guide is brought into contact with the screw mating surface.