Multi-articulated Link Knee Joint Cylinder Position Detection
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Solution Overview
Problem
Existing multi-articulated link knee joints require expensive special fluid cylinders with built-in magnets for accurate bending angle detection, increasing costs.
Innovation Solution
A multi-articulated link knee joint design that uses a position detector to measure the relative position of an auxiliary driver, such as a cylinder device, to the lower link unit, allowing for the detection of bending angles without the need for a special auxiliary driver, utilizing components like infrared sensors or Hall elements for position detection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a magnet is built into the piston rod of the fluid cylinder for bending angle detection, then the bending angle detection accuracy is improved, but the manufacturing cost increases
Solution Approach 1:
The detection system is segmented into two independent parts: a position detector attached to the cylinder tube and a separate magnet attached to the piston rod. This segmentation allows each component to be manufactured independently using standard components rather than requiring an integrated special fluid cylinder, thereby reducing manufacturing cost while maintaining detection accuracy.
Solution Approach 2:
A magnet is introduced as an intermediary element that mediates between the piston rod position and the position detector. The magnet serves as a passive marker that can be detected by the position detector without requiring complex integration, enabling accurate position detection while keeping the fluid cylinder itself unchanged and easy to manufacture.
2Reliability
If a special fluid cylinder with built-in magnet is used for position detection, then the bending angle detection reliability is improved, but the device complexity increases
Solution Approach 1:
The detection system is divided into separate components: the position detector remains on the cylinder tube while the magnet is added to the piston rod. This segmentation maintains reliable detection through the magnetic field interaction while avoiding the complexity of integrating the magnet into the piston rod manufacturing process, thus keeping the overall device structure simpler.
Solution Approach 2:
The mechanical connection approach is replaced with a magnetic field-based detection system. Instead of mechanically integrating the magnet into the piston rod, the magnet is attached externally and detected by the position detector, substituting a complex mechanical integration with a simpler magnetic field interaction that maintains reliability while reducing device complexity.
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
Enables cost-effective detection of bending angles, simplifies wiring, and reduces the overall cost of the knee joint while maintaining accurate motion assistance and natural movement similarity to a living knee joint.
Implementation Method 1
a magnetic sensor is provided at a cylinder tube of a fluid cylinder, and a magnet is provided inside a piston rod of the fluid cylinder, which enables detection of the position of the piston rod relative to the cylinder tube
Data Source
AI summary
A multi-articulated link knee joint includes: a knee unit in which an upper link unit rotates relative to a lower link unit by a multi-articulated link mechanism including a plurality of link units including the upper link unit and the lower link unit; a cylinder device for assisting the motion of the knee unit and moving in accordance with the rotation of the upper link unit; a position detector for detecting the distance from the lower link unit to the cylinder device; and an angle detector for obtaining the bending angle of the knee unit from the detected distance from the cylinder device.