Robot Grinding Speed Control for Scratch-Free Surface Contact
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Solution Overview
Problem
Conventional robot-supported grinding machines face challenges in accurately regulating processing force due to high mass inertia in industrial robots, leading to potential scratches or grooves during surface machining.
Innovation Solution
A grinding apparatus with a motor-driven grinding tool and control system that adjusts rotational speed upon contact detection, using a linear actuator to control contact force and position the grinding tool, allowing for precise force regulation and gentle surface contact.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the grinding machine is switched on when the grinding disc comes into contact with the machined surface, then grinding can be performed, but scratches or grooves may occur on the machined surface
Solution Approach 1:
The grinding disc is accelerated to the operating rotational speed before contact with the workpiece surface. This preliminary acceleration ensures the disc is already running at optimal speed when grinding begins, preventing scratches that would occur if the disc started from low speed at the moment of contact.
Solution Approach 2:
The system dynamically adjusts the rotational speed of the grinding disc based on the contact state. The disc rotates at a lower first rotational speed during approach and positioning, then transitions to a higher second rotational speed upon contact detection, optimizing both surface quality and grinding efficiency throughout the process.
2Extent of automation
If the grinding machine is positioned using a robot manipulator, then automated positioning along a trajectory is achieved, but the mass inertia of the robot arm prevents quick reaction to processing force variations
Solution Approach 1:
The system transitions from static robot positioning to dynamic force control by switching the controller to force control mode upon contact detection. This enables real-time adaptation to processing force variations that rigid position control cannot handle, improving reliability while maintaining automation.
Solution Approach 2:
The control parameters are dynamically changed from position control to force control based on contact detection. This parameter switching allows the system to leverage the robot's positioning accuracy during approach while utilizing force control's ability to respond to contact force variations during grinding.
3Manufacturing precision
If the rotational speed is increased from the first rotational speed to the second rotational speed upon contact detection, then surface quality is improved, but energy consumption increases
Solution Approach 1:
The grinding process uses periodic speed variation: low speed during approach and positioning, high speed during actual grinding contact. This periodic action reduces overall energy consumption compared to maintaining high speed throughout, while ensuring high surface quality during the critical grinding phase.
Data Source
AI summary
The invention relates to a method for the automated grinding of surfaces and to a corresponding device. According to one exemplary embodiment, the method comprises the robot-assisted positioning of a grinding machine with a grinding tool, so that the grinding tool contacts the surface when the grinding machine is operated at a first rotational speed, and the detection of the contact between the grinding tool and the surface. The method further comprises, as a result of detecting the contact, the increase in the rotational speed of the grinding tool from the first rotational speed to a second rotational speed.