Cable Position Sensor with Gimbal Guide for Rehabilitation
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Solution Overview
Problem
Rehabilitation devices for patients with reduced upper extremity functionality require an accurate and efficient method to determine the position of the extremity without relying on external sensors like cameras, while also providing adjustable force to assist in movement rehabilitation.
Innovation Solution
A position sensor system utilizing a cable winding device with an electric drive to determine unwinding length and angular position, combined with a guiding device featuring a centering and gimbal-mounted outlet apparatus, allows precise calculation of the cable's position using vector geometry, and an adjustable tensile force is applied via an electric motor and force measuring device.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a cable system with weight system and roller is used to determine arm position, then the position can be determined, but the spatial requirements are large and the accuracy is limited
Solution Approach 1:
The patent replaces the traditional mechanical cable system with weights and rollers with an electrically driven winding device. The electric drive unit unwinds and winds the cable, and a encoder determines the unwound cable length, eliminating the need for large weight systems and complex mechanical guidance structures while achieving higher measurement precision.
Solution Approach 2:
The patent introduces a guiding device with centering and outlet apparatus as an intermediary between the winding device and the cable. This guiding device ensures precise cable routing and enables accurate determination of the cable exit angle, thereby improving position determination accuracy without requiring large spatial dimensions.
2Measurement precision
If external sensors like cameras are used to calculate position, then position can be determined, but the device complexity and spatial requirements increase
Solution Approach 1:
The patent combines multiple measurement functions into a single integrated position sensor. The winding device, guiding device, encoder for cable length measurement, and position sensor for exit angle measurement are merged into one unit, eliminating the need for separate external cameras and complex computational systems while maintaining high measurement precision.
Solution Approach 2:
The position sensor system is self-sufficient and does not require external sensors or cameras. The encoder on the winding device directly measures the unwound cable length, and the position sensor on the guiding device directly measures the exit angle, enabling the system to determine cable position independently without external assistance.
3Adaptability or versatility
If no adjustable force is applied to the cable, then the system is simpler, but the ability to assist patient movement is reduced
Solution Approach 1:
The patent makes the cable tension dynamic and adjustable through the electric drive unit. The electric motor can apply variable tensile force to the cable, allowing the system to adapt to different patient needs and movement stages. This dynamic capability is integrated into the existing position sensor structure without adding separate force application mechanisms.
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 accurate and efficient determination of the extremity's position with reduced spatial requirements and adjustable force application, facilitating rehabilitation by relieving the patient's internal strength and allowing for graphical visualization of movement without external sensors.
Implementation Method 1
a force measuring device with a fixed connection to the holder
Implementation Method 2
The electric motor is set up to act on the cable with an adjustable tensile force
Implementation Method 3
the position sensor incorporates one or multiple acceleration sensors, which enable an angular position of the outlet apparatus
Implementation Method 4
a gimbal-mounted outlet apparatus for the passing through of the cable in a variable direction
Data Source
AI summary
Position sensor having a holder, a force measuring device permanently connected to the holder, and a winding device, which is permanently connected to the force measuring device and has a drive having an electric motor. Winding device is configured to unwind and wind a cable and to determine an unwinding length of the cable. Guide device permanently connected to the holder has a centering device for passing through the cable, an outlet apparatus which is mounted on universal joints and is intended to pass through the cable with a variable direction, and a position sensor for determining an angular position of the outlet apparatus. Position sensor is set up to determine position of a predetermined point of the cable relative to holder on the basis of determined angular position and unwinding length.