Robot Joint Torque Sensor Layout for Accurate Bearing-Supported Control
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Solution Overview
Problem
Conventional joint mechanisms with output links supported via multiple bearings face challenges in accurately detecting torque, leading to inadequate torque control accuracy and sensitivity, which hinders precision assembly work in robots.
Innovation Solution
The joint mechanism is designed with both bearing mechanisms positioned on the driving-portion-side torque transmission path, ensuring that the torque applied to the output link is transmitted directly to the torque sensor without interference from reaction forces, allowing for high-accuracy torque detection and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the output link is supported via multiple bearings to ensure mechanical robustness, then the mechanical stability is improved, but the torque detection accuracy deteriorates due to interference from reaction forces
Solution Approach 1:
The patent segments the bearing support system into two distinct parts: bearings supporting the driving portion and bearings supporting the output link. This segmentation allows the torque sensor to be positioned on the driving portion side, where it can accurately detect torque without being affected by reaction forces from the output link bearings.
Solution Approach 2:
The patent introduces a torque sensor as an intermediary element between the driving portion and the output link. This intermediary device measures the torque transmitted through the driving portion before it reaches the output link, thereby avoiding the interference of reaction forces that would occur if the sensor were placed on the output link side.
2Measurement precision
If the torque sensor is placed on the output link side to directly measure output torque, then the measurement directness is improved, but the control sensitivity deteriorates due to interference from bearing reaction forces
Solution Approach 1:
The torque sensor is positioned as an intermediary on the driving portion side, measuring torque before it is transmitted to the output link. This positioning allows accurate torque detection without the sensor being subjected to the complex reaction forces generated by the output link bearings, thereby maintaining both measurement accuracy and control sensitivity.
Solution Approach 2:
The patent extracts the torque sensing function from the output link side and relocates it to the driving portion side. This extraction removes the sensor from the environment where it would be subjected to interfering reaction forces, while still allowing it to measure the torque that will be transmitted to the output link.
3Measurement precision
If complex control methods are used to compensate for reaction forces, then the torque control accuracy can be maintained, but the device complexity increases
Solution Approach 1:
The patent extracts the torque measurement function from the output link side and relocates it to the driving portion side, where reaction forces do not interfere. This extraction eliminates the need for complex control methods to compensate for bearing reaction forces, as the sensor naturally operates in an environment free from such interferences.
Solution Approach 2:
By introducing the torque sensor as an intermediary on the driving portion side, the system obtains accurate torque measurements without requiring complex control algorithms to compensate for bearing reaction forces. The intermediary positioning of the sensor simplifies the control system while maintaining high torque control accuracy.
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 enhances the sensitivity and accuracy of torque control in robots, enabling them to perform precision assembly work without complex control methods or pre-determination of reaction forces.
Implementation Method 1
The torque sensor includes an elastic member that deforms in accordance with the torque applied to the elastic member, and measures the output torque by detecting the amount of deformation or distortion of the elastic member.
Data Source
AI summary
A driving apparatus is configured to displace a second link with respect to a first link. The driving apparatus includes a driving portion including an output portion configured to output a driving force that displaces the second link, a sensor configured to obtain information on force, a connection member configured to connect the output portion and the sensor, a first bearing, and a second bearing. The sensor is connected between the second link and the connection member. The first bearing and the second bearing are connected to the connection member for displacing the second link with respect to the first link.