Hand-Guided Robot Position Correction Under External Joint Moments
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Solution Overview
Problem
Conventional robotic models fail to accurately predict the position of a robot's end effector when interacting with external objects due to unaccounted mechanical tensions and user-induced forces, leading to significant positioning errors.
Innovation Solution
A method involving the measurement of total moments at each joint of a hand-guided robot's arm during contact with an external object, computation of a positional correction factor, and continuous determination of the end effector's current position to minimize the difference between modeled and actual positions, incorporating dynamic influences like centrifugal and Coriolis forces.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional robotic models are used to predict end effector position, then the system is simple and easy to operate, but positioning accuracy deteriorates significantly when the robot contacts external objects
Solution Approach 1:
The patent introduces moment measurements as an intermediary variable to bridge the gap between the simple control model and the complex physical interactions. By measuring moments at the joints and using them to compute correction factors, the system indirectly accounts for mechanical tensions and external forces without requiring a completely complex dynamic model, thus improving positioning accuracy while maintaining relative simplicity
Solution Approach 2:
The patent implements feedback by continuously measuring moments at the robot joints, computing positional correction factors based on these measurements, and applying corrections to the end effector position. This closed-loop feedback mechanism compensates for positioning errors caused by mechanical tensions and external object interactions, significantly improving measurement precision
2Measurement precision
If the robot model accounts for mechanical tensions and external forces, then positioning accuracy improves, but the computational complexity and measurement requirements increase
Solution Approach 1:
The patent leverages the robot's existing joint moment measurements, which are typically already available from the robot's control system for standard operations. By utilizing these self-generated measurements and processing them through the correction factor computation, the system improves positioning accuracy without requiring additional external sensors or complex measurement apparatus
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 significantly improves positional accuracy of the end effector, enabling precise tracking and virtual modeling of external objects, reducing the risk of damage and enhancing automation in complex tasks.
Implementation Method 1
a total moment affecting the robot is measured at each joint of the arm while the robot is being hand-guided and subjected to a mechanical tension due to contact with an external object
Implementation Method 2
The total moment may for example include an influence of a centrifugal force
Implementation Method 3
The total moment may for example include an influence of a Coriolis force
Data Source
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AI summary
The invention relates to a method (25) for operating a hand-guided robot (2) having a jointed arm (9) and an end effector (11). As part of the method (25) a moment is measured at each joint (7) while the robot (2) is being hand-guided or subjected to a mechanical tension due to contact with an external object (14, 17). Based on the measured moment an external moment affecting the robot (2) is determined. Then, a correction factor for a position of the end effector (11) is computed based on the external moment and an absolute accurate model of the robot (2). Then, a current position of the end effector (11) is computed based on a correction model in dependence on the correction factor. The invention also relates to a corresponding storage medium (23), data processing device (3), robotic system (1), and tracking system.