Workpiece Contact State Estimation Using Force Ranges
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Solution Overview
Problem
Existing technologies fail to accurately identify the pattern of contact between a workpiece and a peripheral object during movement, leading to improper correction of the workpiece's position or posture, especially when the workpiece has not yet entered a hole, resulting in potential obstruction.
Innovation Solution
A device and method that estimate the state of contact by acquiring measurement values of contact acting force and using an estimation processing unit to determine the actual contact state based on pre-defined feasible contact acting force ranges, considering factors like friction and drag direction, to correctly align the workpiece with the peripheral object.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If force control is performed based on maximum detection value or first contact value, then the workpiece posture can be corrected, but the contact state pattern cannot be accurately identified, leading to improper correction when the workpiece has not yet entered the hole
Solution Approach 1:
The contact state identification is segmented into multiple distinct patterns (first pattern: corner contact with opening end, second pattern: side surface contact with opening end, third pattern: corner contact with side wall, fourth pattern: side surface contact with side wall). Each pattern has its own characteristic force range, allowing accurate identification and appropriate correction for each specific contact situation.
Solution Approach 2:
The feasible force ranges for different contact state patterns are determined in advance through analysis before actual operation. This preliminary determination of force ranges for each contact pattern enables the system to quickly identify the current contact state and apply the appropriate correction strategy without delay.
2Device complexity
If a single force control strategy is used for all contact situations, then the control system is simple, but it cannot properly handle different contact patterns, causing obstruction when the workpiece contacts peripheral objects
Solution Approach 1:
The control system dynamically adapts to different contact situations by identifying the current contact state pattern and selecting the appropriate correction strategy. The system transitions from a static single-strategy approach to a dynamic multi-strategy approach that adjusts control parameters based on real-time contact state identification.
Solution Approach 2:
Different control parameters and correction strategies are applied based on the identified contact state pattern. The system changes operational parameters (such as correction direction, force magnitude, and movement trajectory) according to which contact pattern is detected, enabling smooth workpiece movement for each specific contact situation.
3Productivity
If the workpiece movement is corrected without accurate contact state identification, then the operation speed is fast, but the correction is improper, leading to potential obstruction
Solution Approach 1:
The feasible force ranges for different contact state patterns are determined in advance through analysis before actual operation. This preliminary determination enables rapid identification of the current contact state during operation, allowing the system to immediately apply the appropriate correction strategy without slowing down the overall operation.
Solution Approach 2:
The system continuously monitors the detection values of forces acting on the workpiece and compares them against the pre-determined feasible force ranges for different contact patterns. This feedback mechanism enables real-time identification of the contact state pattern and automatic selection of the appropriate correction strategy, maintaining both speed and reliability.
Data Source
AI summary
The present invention provides a workpiece contact state estimating device and a workpiece contact state estimation method to estimate an actual state of contact of a workpiece A with a peripheral object on the basis of a feasible contact acting force range, which is a feasible range of the value of a contact acting force (the force acting on a manipulator 1 generated by contact) prepared in advance for each of a plurality of types of contact states that are feasible as the states of contact of the workpiece A with the peripheral object, and a measurement value of the contact acting force at the time of contact of the workpiece A with the peripheral object.