Robotic Actuator Torque Sensor Isolation With Bearing-Supported Flanges
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Solution Overview
Problem
Integrating a sensitive torque sensor into a robotic joint is challenging due to the need to decouple it from non-sensing forces and moments, and conventional designs often result in complex and bulky mechanical structures.
Innovation Solution
The actuator design includes a center shaft, input and output flanges radially fixed with bearings, and a torque sensor connected between them, isolating disturbances and ensuring reliable torque measurements by using the shaft and outer shell as datums for alignment and support.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the torque sensor is integrated into the robotic joint using conventional designs, then the joint can achieve torque measurement capability, but the mechanical structure becomes complex and bulky
Solution Approach 1:
The patent combines the torque sensor with the existing joint structure by integrating it between the input flange and output flange that are already coaxially installed on the center shaft. This merging approach allows torque measurement capability to be added without creating a separate bulky mechanical structure, as the sensor utilizes the existing flange arrangement and bearing support system.
Solution Approach 2:
The input flange and output flange serve multiple functions: they provide mechanical connection for torque transmission, establish coaxial alignment through bearing support, and simultaneously serve as mounting interfaces for the torque sensor. This multi-functionality eliminates the need for additional dedicated sensor mounting structures, reducing overall mechanical complexity.
2Measurement precision
If the torque sensor is placed in the robotic joint, then torque control can be achieved, but the sensor is exposed to disturbances from non-sensing forces and moments
Solution Approach 1:
The patent extracts the torque sensing function from the general joint structure by placing the torque sensor in a dedicated position between the input and output flanges. This extraction allows the sensor to measure torque independently while the bearing support system isolates it from other forces and moments that act on the joint, preventing cross-contamination of measurements.
Solution Approach 2:
The input flange and output flange act as intermediary elements between the torque sensor and the rest of the joint mechanism. These flanges transmit torque to the sensor while the bearing support system mediates by providing radial fixation that blocks transmission of non-sensing forces and moments to the sensor, effectively filtering out harmful disturbances.
3Measurement precision
If the torque sensor is decoupled from non-sensing forces, then measurement accuracy improves, but the mechanical design becomes more complex
Solution Approach 1:
The patent segments the joint into distinct functional zones: the bearing support system handles radial fixation and disturbance isolation, while the flange-sensor assembly handles torque measurement. This segmentation allows each component to be optimized for its specific function without requiring the entire mechanism to be redesigned, maintaining simplicity while achieving decoupling.
Solution Approach 2:
Instead of isolating the torque sensor from the joint structure through complex mounting arrangements, the patent inverts the approach by having the joint structure (through bearings and flanges) actively provide the isolation. The bearing support system and flange arrangement create a naturally isolated sensing environment, simplifying the overall design while achieving the same decoupling effect.
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 reliability of torque sensor readings by isolating disturbances and providing robust support against vibrations, allowing for high-fidelity axial torque measurement.
Implementation Method 1
The input flange and the output flange are radially fixed with the center shaft through a plurality of bearings
Data Source
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AI summary
An actuator of a robotic system and a robot are provided. The actuator (10) may include a center shaft (12), an outer shell (11) connected to the center shaft (12), an input flange (14), and an output flange (16) coaxially installed on the center shaft (12), a torque sensor (15) and a motor assembly (13). The input flange (14) and the output flange (16) are radially fixed with at least one of the outer shell (11) and the center shaft (12) through a plurality of bearings (20). The torque sensor (15) is connected between the input flange (14) and the output flange (16). The motor assembly is coupled to the input flange (14). Disturbances transmitted from either side of the torque sensor (15) may be isolated from the torque sensor (15). Therefore, the reliability of the readings of the torque sensor may be improved.