Robotic Sanding Force Control for Precise Surface Processing
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Solution Overview
Problem
Existing automated finishing systems lack the ability to autonomously process parts with high precision and accuracy, particularly in terms of controlling the force applied by sanding tools, leading to inefficiencies and inconsistencies in surface processing.
Innovation Solution
A robotic system equipped with an optical sensor and sanding head that autonomously scans a part, captures optical images, and adjusts the sanding force in real-time to maintain a target force value based on tool characteristics and surface contours, using a controller to define and execute a toolpath with high-resolution accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If high-resolution scanning is used to achieve precise surface processing, then manufacturing precision is improved, but productivity deteriorates due to increased execution time
Solution Approach 1:
The patent divides the scanning process into two distinct phases: a low-resolution pre-scan phase that captures overall part geometry and identifies surface contours, and a high-resolution scan phase that focuses only on critical processing areas. This segmentation allows the system to achieve high manufacturing precision where needed while maintaining productivity by avoiding unnecessary high-resolution scanning across the entire part surface.
Solution Approach 2:
The system performs a preliminary low-resolution scan before the high-resolution scan to pre-identify surface contours, critical areas, and toolpath parameters. This preliminary action provides the foundation for subsequent high-precision processing without requiring the entire high-resolution scanning process, thereby resolving the contradiction between precision and productivity.
2Manufacturing precision
If real-time force control is implemented to maintain target force values, then manufacturing precision is improved, but device complexity increases
Solution Approach 1:
The patent implements a feedback control mechanism where force sensors continuously monitor the actual sanding force applied to the part surface. The controller compares the measured force with the target force value and automatically adjusts sanding head parameters (such as downforce, speed, or orbital motion) to maintain the desired force level. This feedback loop achieves high manufacturing precision through real-time force control while managing device complexity through automated control algorithms.
3Productivity
If low-resolution scanning is used to reduce execution time, then productivity is improved, but measurement precision deteriorates
Solution Approach 1:
The patent applies local quality by performing high-resolution scanning only in specific critical areas identified during the preliminary low-resolution scan, such as complex contours, transition zones, or areas requiring precise toolpath generation. The majority of the part surface is processed using low-resolution data, which is sufficient for general geometry capture. This approach maintains measurement precision where it matters most while achieving high productivity through selective high-resolution scanning.
Data Source
AI summary
One variation of a method for autonomously scanning and processing a part includes: accessing a part model representing a part positioned in a work zone adjacent a robotic system; retrieving a sanding head translation speed; retrieving a toolpath for execution on the part defining positions, orientations, and target forces applied by the sanding head to the part. The method includes traversing the sanding head along the toolpath, at the sanding head translation speed; reading a sequence of applied forces from a force sensor coupled to the sanding head at positions along the toolpath; and deviating from the toolpath to maintain the set of applied forces within a threshold difference of a sequence of target forces along the toolpath. In one variation of the method, the robotic system executes a toolpath at a duration less than target duration by selectively varying target force and sanding head translation speed across the part.