Robot Joint Force Sensor Layout for Accurate Torque Detection
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Solution Overview
Problem
Conventional multijoint robots face difficulties in accurately detecting forces in directions other than the driving axis due to interference from other axial directions, leading to measurement errors and inability to handle fragile or lightweight objects with precision.
Innovation Solution
A driving mechanism is introduced that simplifies the transfer pathway of forces to a force sensor, allowing for high-precision detection and correction of sensor errors caused by interference in other axial directions, enabling accurate force control around the driving axis.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a force sensor is mounted on a joint to detect torque around the driving axis, then driving control precision is improved, but measurement accuracy deteriorates due to interference from forces in other axial directions
Solution Approach 1:
The force sensor is divided into multiple detection elements arranged in specific patterns around the driving axis. Each element detects forces in specific directions, and through segmented measurement and calculation, the torque around the driving axis is extracted while eliminating interference from other directional forces.
Solution Approach 2:
Different detection elements are positioned at specific locations with different orientations to detect specific force components. By optimizing the local arrangement and orientation of each detection element, the sensor achieves selective sensitivity to torque around the driving axis while being insensitive to forces in other directions.
2Reliability
If a multijoint robot uses dedicated apparatuses or tools for specific processes, then process specialization is improved, but adaptability deteriorates and significant time and costs are spent on preparation
Solution Approach 1:
The multijoint robot is equipped with force sensors and control systems that enable it to perform multiple functions across different processes. The robot can adapt to various tasks including handling fragile objects, lightweight components, and precision assembly operations through unified force control, eliminating the need for dedicated apparatuses for each specific process.
3Measurement precision
If force feedback control is implemented using a force sensor, then force control precision is improved, but device complexity increases due to additional sensors and control systems
Solution Approach 1:
The force sensor is integrated directly into the joint structure of the robot arm, merging the sensing function with the mechanical structure. This integration reduces the need for separate mounting components and simplifies the overall system architecture while maintaining high force control precision.
Solution Approach 2:
The force sensor utilizes the joint's existing mechanical elements and force transmission paths to perform detection, eliminating the need for additional complex sensing mechanisms. The sensor leverages the natural force flow in the joint structure to achieve accurate torque measurement with minimal additional components.
Data Source
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AI summary
A driving mechanism for driving a first link and a second link relative to each other comprises a driving apparatus that includes a fixed part and a part to be driven and drives the part to be driven relative to the fixed part, and a constraining part that includes a first supporting part and a second supporting part and constrains the first link and the second link so as to be movable in a predetermined direction, wherein one of the fixed part and the part to be driven is fixed to the first link, the first supporting part is fixed to the first link, the second supporting part is fixed to another of the fixed part and the part to be driven, and a sensor for determining force acting on the second link is attached so as to link the other of the fixed part and the part to be driven and the second link.