Robot End Alignment by Contact Rotation and Displacement Feedback
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Solution Overview
Problem
Industrial robots face challenges in maintaining accurate relative position and orientation with target objects due to low positioning accuracy of moving platforms and noise interference in force/torque detection, especially when contact surfaces are small.
Innovation Solution
A method for aligning a robot end with a target object by establishing a coordinate system, controlling surface movement, and determining the correct rotation direction based on force information and displacement relationships, allowing for posture alignment without high-accuracy force/torque sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If force control compliance strategy is used to adjust position and orientation based on external force detection, then posture compliance control is achieved, but detection accuracy is insufficient due to noise interference when contact surface is small
Solution Approach 1:
The patent introduces a mediator (the alignment method using displacement relationship) between the robot end and target object to achieve alignment without relying on noisy external force detection. The mediator translates the alignment problem into a displacement measurement problem that can be solved more accurately.
Solution Approach 2:
The patent replaces the mechanical force detection system with a displacement measurement system. By measuring the displacement of the control point along the z-axis during rotation, the system achieves alignment without relying on noisy force/torque sensors.
2Ease of operation
If pre-calibrated position control is used to operate robot end, then operation simplicity is maintained, but positioning accuracy deteriorates due to unchanged relative position requirements
Solution Approach 1:
The patent transforms the static pre-calibrated position control into a dynamic alignment process. The robot end actively rotates during operation to adapt to changes in relative position and orientation, maintaining alignment through continuous adjustment rather than fixed calibration.
Solution Approach 2:
The patent changes the control parameters from fixed pre-calibrated positions to dynamic displacement measurements. By measuring and responding to actual displacement during operation, the system adapts to changing conditions while maintaining alignment accuracy.
Data Source
AI summary
A method for aligning a robot end with a target object includes: acquiring a target direction for a surface to be aligned; selecting a control point, and establishing a coordinate system of the control point; controlling the surface to move along a direction such that the z-axis points in the target direction; rotating, when the surface is determined to be in contact with the target object, the surface with respect to the target object actively and keeping the surface in contact with the target object, and acquiring a first displacement of the control point; determining a relationship between the first displacement and the z-axis; determining, based on the relationship between the first displacement and the z-axis, whether a current rotation direction is a correct alignment direction; and controlling, based on the determination, the surface to be rotated.