RTCP Robot Path Tracking for Real-Time Tool Tip Offset Control
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Solution Overview
Problem
Existing robotic path tracing methods are limited by their inability to control tool tip offsets in real-time and require additional machinery or labor to handle workpieces before and after processing.
Innovation Solution
The method employs a remote tool center point (RTCP) coordinate frame to dynamically modify the robot's path, allowing real-time tracking and adjustment of tool tip offsets using a sensor, while the robot moves the workpiece relative to a fixed processing tool.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional path tracing methods are used with workpiece fixtures, then the tool tip can trace continuous paths on the workpiece, but additional machinery or labor is required to handle workpieces before and after processing
Solution Approach 1:
The patent inverts the traditional approach by making the workpiece movable instead of fixed, and the processing tool stationary. The robot manipulator holds and moves the workpiece through the processing tool's path, rather than moving the tool over a fixed workpiece. This inversion eliminates the need for fixtures and handling machinery while maintaining continuous path tracing capability
Solution Approach 2:
The robot manipulator performs multiple functions: it holds the workpiece, moves it through the processing path, and positions it for successive operations. This self-service capability eliminates the need for separate handling machinery or human intervention between workpieces, enabling continuous operation
2Manufacturing precision
If offsets are calculated in world coordinate frame, then the nominal path can be defined on the workpiece, but real-time tracking and control of tool tip offset is impossible or impractical
Solution Approach 1:
The patent introduces a new dimension by defining the offset in the RTCP coordinate frame (attached to the processing tool) rather than the world coordinate frame. This dimensional change allows the offset to be expressed relative to the tool's orientation and position, enabling real-time tracking and control as the tool moves through the workpiece along the nominal path
Solution Approach 2:
The system implements real-time feedback by continuously tracking the actual tool tip offset during processing and using this information to adjust the robot manipulator's motion. This feedback mechanism enables dynamic correction and precise control of the offset, ensuring manufacturing precision throughout the operation
Data Source
AI summary
A method for performing robot dynamic path modification using a remote tool center point (RTCP) coordinate frame, for applications such as material dispensing. A processing tool is fixedly mounted in a workcell and the robot holds and moves the workpiece during the processing. The RTCP coordinate frame is defined at the tip of the tool. A nominal processing path on the workpiece is defined, and a prescribed offset distance from the tip of the tool to the workpiece is defined. A sensor measures the actual offset distance from the tool tip to the workpiece. A controller applies the offset in the RTCP coordinate frame and calculates robot motions causing the robot to move the workpiece nominal path past the tool tip at the offset distance. The controller converts the offset from the RTCP frame to a workcell frame, and performs inverse kinematics calculations to generate robot joint motion commands.