Force-Controlled Robot Insertion on a Moving Conveyor Workpiece
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Solution Overview
Problem
Existing robot control systems struggle to ensure accurate and efficient operation when the workpiece moves out of the robot's movement range due to the time taken for the operation, leading to incomplete tasks.
Innovation Solution
A robot control method and system that utilize force control and precise positioning to perform an insertion operation, where the robot follows a conveyor-borne workpiece and adjusts its attitude to ensure accurate insertion into a moving target, using a force sensor for feedback control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If the robot performs operation on the workpiece at normal speed, then the operation can be completed with sufficient accuracy, but the workpiece may move out of the robot's movement range before the operation is finished
Solution Approach 1:
The robot dynamically adjusts its movement speed based on real-time feedback from the force sensor. During the insertion operation, the robot moves at a slower speed to ensure precision when contact is detected, while moving faster during non-contact phases. This dynamic speed adjustment allows the robot to complete the operation accurately within the workpiece's movement range.
Solution Approach 2:
The force sensor provides real-time feedback on the contact force between the end effector and the workpiece. This feedback enables the robot to detect when insertion has begun and adjust its speed and position accordingly, ensuring accurate completion of the operation before the workpiece moves out of range.
2Productivity
If the robot moves faster to complete operation in shorter time, then productivity improves, but the operation accuracy decreases
Solution Approach 1:
The robot employs periodic action by alternating between high-speed movement phases and low-speed precision phases. During approach and retraction, the robot moves at high speed to maximize productivity. During the critical insertion phase when the end effector contacts the workpiece, the robot switches to low-speed mode to ensure accuracy, then returns to high speed after insertion is complete.
Solution Approach 2:
The robot changes its movement parameters (speed, acceleration) based on the operation phase and force sensor feedback. The control system adjusts velocity and acceleration parameters dynamically: high velocity during non-contact movement, low velocity during contact and insertion, optimizing both productivity and precision at different stages of the operation.
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 approach allows for more accurate and efficient completion of insertion operations within a shorter time frame, preventing workpieces from moving out of the robot's range before the operation is finished.
Implementation Method 1
a force sensor that detects an acting force acting on the insertion receiving object from the end effector
Data Source
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AI summary
A robot control method for a robot (200) performing an insertion operation of inserting a second target object (Q) with force control into a first target object (W) conveyed by a conveyor device (600) is provided. The robot control method includes: a follow step (S71) of causing the second target object (Q) to follow the first target object (W) from an operation start location (L2), based on a conveyance speed of the first target object (W); a contact step (S73, S74) of bringing the second target object (Q) into contact with the first target object (W), the second target object (Q) being in a tilted attitude in relation to the first target object (W), with the force control; an attitude change step (S75) of changing the attitude of the second target object (Q) in such a way that the tilt in relation to the first target object (W) is eliminated, while pressing the second target object (Q) against the first target object (W), with the force control; and an insertion step (S76) of inserting the second target object (Q) into the first target object (W).