Robot Joint Torque Sensor Layout for Compact Arm Drive
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Solution Overview
Problem
Existing robot arm driving mechanisms face challenges in preventing torque sensor wire bending and twisting, leading to reduced lifespan, and also result in increased joint length and limited motor placement options due to the arrangement of torque sensors.
Innovation Solution
A driving mechanism that positions the torque sensor between the reduction gear and the first link, with the input shaft penetrating through the torque sensor's hollow portion, allowing for relative displacement of links and minimizing wire deformation while enabling motor placement flexibility.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If the torque sensor is arranged at a position where the wire is less affected by joint rotation, then the wire lifespan is extended, but the joint length increases
Solution Approach 1:
The patent applies nesting by placing the torque sensor inside the hollow portion of the input shaft. The input shaft is designed with a hollow cylindrical structure, and the torque sensor is nested within this space. This allows the torque sensor to be positioned at the input shaft location (where wire deformation is minimized) without increasing the overall joint length, as it utilizes the internal hollow space rather than adding external components.
Solution Approach 2:
The patent transitions from a linear arrangement (components placed in series along the rotation axis) to a three-dimensional arrangement by utilizing the hollow internal space of the input shaft. Instead of extending the joint length in one dimension, the solution moves the torque sensor into another dimension (the radial hollow space), thereby solving the contradiction between wire protection and compact joint design.
2Length of moving object
If the motor is arranged in series in the rotation axis C direction, then the joint length is reduced, but the range of motor choice is narrowed
Solution Approach 1:
The patent enables motors to be arranged in multiple dimensional configurations (parallel to the rotation axis, perpendicular, or at angles) by utilizing the three-dimensional space within and around the hollow input shaft. This breaks the constraint of series arrangement along the rotation axis, allowing engineers to select from a broader range of motor types and orientations while maintaining compact joint dimensions.
Solution Approach 2:
The hollow input shaft structure serves multiple functions: it acts as a structural component for torque transmission, provides housing space for the torque sensor, and creates flexible mounting space for the motor in various orientations. This multi-functionality increases adaptability without compromising joint compactness.
Data Source
AI summary
A driving mechanism that relatively displaces first and second links includes a motor, a reduction gear, and a torque sensor including a hollow portion, wherein the reduction gear includes an input shaft that is rotated by drive of the motor, the torque sensor is arranged between the reduction gear and the first link, and the input shaft penetrates through the hollow portion of the torque sensor.