Robot Arm Base Layout for Accurate Force Sensing
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Solution Overview
Problem
In existing robot configurations, the detection accuracy of force sensors is compromised due to torque under the arm's weight when the arm is positioned off-center relative to the base, leading to reduced precision in force detection.
Innovation Solution
The robot design positions the force detection unit closer to the axis of rotation of the first arm, shifting the arm's coupling from the base's center line, thereby reducing the inertial moment and enhancing the accuracy of force detection by minimizing constant forces applied to the sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the force sensor is provided below the base with the center axis of the force sensor coinciding with the center axis of the base, then the structure is simplified and easy to manufacture, but torque under the arm's weight is constantly applied to the force sensor when the arm is coupled to a position shifted from the center line, reducing detection accuracy
Solution Approach 1:
The patent applies asymmetry by deliberately misaligning the force sensor's center axis relative to the base's center axis. The force sensor is positioned such that its center axis is offset from the base center, creating an asymmetric configuration that eliminates constant torque on the sensor when the arm operates on the base center line, thereby improving force detection accuracy
Solution Approach 2:
The patent applies local quality by positioning the force sensor at a specific location where its center axis is offset from the base center. This localized positioning creates a specific geometric relationship between the sensor, base, and arm that minimizes torque interference at the sensor location while maintaining overall structural integrity
2Adaptability or versatility
If the arm is coupled to the base at a position shifted from the center line, then the robot can perform work operations, but torque under the arm's weight is constantly applied to the force sensor, compromising detection accuracy
Solution Approach 1:
The patent resolves this contradiction by creating an asymmetric configuration where the force sensor's center axis is offset from the base center line. This asymmetric positioning ensures that when the arm operates on the base center line, no constant torque is applied to the sensor, allowing both work operations and accurate force detection to coexist
Solution Approach 2:
The patent introduces a geometric relationship as an intermediary between the arm position and force sensor. By carefully designing the offset distance between the force sensor center axis and base center line, the system mediates between the need for arm work operations and the need for accurate force detection, eliminating torque interference
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 configuration improves the detection accuracy of the force sensor, allowing for more precise control of the robot arm even when external forces are applied, by reducing the impact of torque from the arm's weight on the force detection unit.
Implementation Method 1
torque under the arm's weight is constantly applied to the force sensor
Implementation Method 2
torque under the arm's weight is constantly applied to the force sensor
Data Source
AI summary
A robot includes a base, a robot arm having a first arm coupled to the base and rotating about a first axis, and a force detection unit provided in the base and detecting a force acting on the base or the robot arm, wherein the first arm is coupled to the base in a position shifted from a first center line passing through a center of the base and being parallel to the first axis, and a second center line passing through a center of the force detection unit and being parallel to the first axis is closer to the first axis than the first center line.