Rotation-shaft joint structure with uniaxial strain sensor
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Solution Overview
Problem
Existing rotation-shaft joint structures lack an efficient and cost-effective method to detect strain and contact between a link member and an object, particularly in multi-joint configurations, where direct contact with sensors can lead to nipping and increased costs with torque or capacitance sensors.
Innovation Solution
A rotation-shaft joint structure incorporating a driving-force generating part with a fixed and movable member, a link member, and a uniaxial strain sensor attached to the link or movable member, positioned between the fixed and outer circumferential surfaces, to detect strain and contact without direct object interaction, using screws for attachment and potentially including amplifiers and serial communication circuits for efficient signal transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If torque sensors or capacitance sensors are used to detect contact and strain, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The patent uses uniaxial strain sensors instead of expensive torque sensors or capacitance sensors. The uniaxial strain sensor is a simpler, more cost-effective device that can reliably detect strain and contact forces in the link member without requiring complex sensor systems, thereby reducing device complexity while maintaining adequate measurement precision for the application.
Solution Approach 2:
The patent replaces complex sensor systems (torque sensors, capacitance sensors) with a simpler mechanical strain detection approach using uniaxial strain sensors attached to the link member. This substitution reduces device complexity by using straightforward mechanical strain measurement rather than complex electrical or capacitive sensing systems.
2Measurement precision
If sensors are placed in direct contact with the link member to detect contact forces, then measurement precision is improved, but reliability decreases due to nipping risks
Solution Approach 1:
The uniaxial strain sensor acts as an intermediary element attached to the link member. It detects contact forces and strain through its attachment to the link member surface rather than requiring direct exposure to contact objects. This intermediary positioning maintains measurement precision while protecting the sensor from direct contact damage and nipping risks.
3Measurement precision
If multiple sensors are provided to detect strain in multi-joint systems, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The uniaxial strain sensor is designed to be universally applicable across multiple joint configurations. By using the same simple uniaxial strain sensor type for all joint measurements rather than different specialized sensors, the system achieves multi-joint detection capability while avoiding the complexity increase that would result from using multiple different sensor types or complex sensor arrays.
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 allows for reliable detection of contact and strain with reduced costs, improved assembly, and enhanced protection of sensors, even in multi-joint systems, by using uniaxial strain sensors that can operate with parallel circuits and be covered for protection, minimizing direct contact risks and cable complexity.
Implementation Method 1
a uniaxial strain sensor that is attached to the link member or the movable member, at a surface located in a space between a fixed area over which the link member is fixed to the movable member and the outer circumferential surface of the driving-force generating part about the axis, to detect the strain of the surface
Data Source
AI summary
A force acting on a link is detected at low cost. Provided is a rotation-shaft joint structure including: a driving-force generating part including a fixed member that is fixed to a base member, and a movable member that is rotationally driven about a predetermined axis relative to the fixed member; a link member that is fixed to the movable member of the driving-force generating part; and a uniaxial strain sensor that is attached to the link member or the movable member, at a surface located in a space between a fixed area over which the link member is fixed to the movable member and the outer circumferential surface of the driving-force generating part about the axis, to detect the strain of the surface.