Coaxial Actuator With Elastic Torque Sensing for Motion Assistance
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Solution Overview
Problem
Existing actuators for motion assistance devices, such as those used in robots and industrial facilities, face challenges in efficiently transmitting power while accommodating varying user forces, often requiring separate force/torque sensors and amplifiers, which increases size and complexity.
Innovation Solution
The actuator design incorporates a motor, a series of power transmitters performing coaxial rotation, an elastic element connecting adjacent power transmitters, and angle sensors to determine torque based on rotation angles, allowing the controller to adjust power transmission and counteract deformation, thereby reducing size and improving durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If separate force/torque sensors and amplifiers are used to accommodate varying user forces, then the actuator can accurately measure and respond to user forces, but the size and structural complexity of the actuator increases
Solution Approach 1:
The patent combines the force sensing function with the existing angle sensors by using the elastic element's deformation (which reflects user force) to determine interaction force. This merging eliminates the need for separate force/torque sensors and amplifiers, reducing structural complexity while maintaining measurement capability
Solution Approach 2:
The elastic element serves dual purposes: it transmits power between power transmitters and simultaneously provides force sensing capability through its deformation. The system uses its own component (elastic element) to provide the measurement function, eliminating the need for external sensing components
2Adaptability or versatility
If multiple separate components (sensors, amplifiers, power transmitters) are used to handle varying user forces, then the actuator can accommodate different force conditions, but the overall size of the actuator increases
Solution Approach 1:
The elastic element performs multiple functions simultaneously: it transmits power between power transmitters, stores elastic energy, provides force sensing capability, and accommodates varying user forces through its deformation. This multi-functionality reduces the need for separate components, thereby reducing actuator size while maintaining adaptability
Solution Approach 2:
The system accommodates varying user forces by allowing the elastic element to change its deformation parameter in response to different force conditions. The controller adjusts torque based on the deformation amount, enabling the actuator to adapt to different force requirements without adding physical components
3Reliability
If the elastic element connects adjacent power transmitters and allows relative rotation, then the actuator can absorb impact and reduce size, but the torque control between power transmitters becomes more complex
Solution Approach 1:
The controller implements feedback control by continuously monitoring the deformation amount of the elastic element (which reflects the relative rotation between power transmitters) and adjusting the torque accordingly. This feedback mechanism enables precise torque control while maintaining the impact absorption capability of the elastic element
Solution Approach 2:
The system transitions from static rigid connections to dynamic flexible connections using the elastic element. The elastic element allows dynamic adjustment of the connection stiffness based on operating conditions, enabling the system to absorb impact while the controller dynamically adjusts torque to maintain proper operation
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 design enables efficient power transmission, reduces the actuator's size, and enhances durability by absorbing impact without separate sensors, improving the overall performance of motion assistance devices.
Implementation Method 1
an elastic element configured to connect the first power transmitter and the second power transmitter
Data Source
AI summary
An actuator includes a plurality of power transmitters configured to transmit power sequentially, and an elastic element configured to connect a first power transmitter and a second power transmitter that are adjacent to each other and perform a coaxial rotation motion, among the plurality of power transmitters.