String Tension Control Using Twisted String Actuation
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Solution Overview
Problem
Existing exercise equipment fails to provide variable tension control based on user muscle relaxation or contraction, limiting the effectiveness of upper body exercises like standing barbell curls, preacher curls, and spider curls.
Innovation Solution
A tension control apparatus that includes a motor, strings, elastic members, and sensors to dynamically adjust tension based on user input modes and intensity, using a twisted string actuator to twist or untwist strings for varying load resistance during exercises.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a fixed load (weight) is used for exercise, then the equipment structure is simple, but the tension cannot be adjusted to match muscle relaxation or contraction states
Solution Approach 1:
The patent implements dynamic tension control by replacing fixed weight loads with an active motor system that continuously adjusts string tension based on real-time sensor feedback. The motor controller modifies the tension force dynamically during exercise movements, adapting to muscle relaxation and contraction states, thereby transforming a static load system into a dynamic, responsive system.
Solution Approach 2:
The system incorporates sensors (such as force sensors or encoders) that continuously monitor exercise parameters like tension force, position, or velocity. This feedback is processed by a controller that adjusts motor output in real-time to maintain optimal tension levels, creating a closed-loop control system that adapts to the user's physiological state during exercise.
2Manufacturing precision
If a motor system with sensors is added to control tension dynamically, then tension control precision is improved, but the device complexity increases
Solution Approach 1:
The patent replaces complex mechanical tension adjustment mechanisms (such as multiple pulleys, springs, or counterweights) with an electric motor-driven system. The motor, controlled by electronic circuits and software, provides precise tension control through electromagnetic actuation, substituting mechanical complexity with electrical control systems that offer better precision and easier adjustment.
Solution Approach 2:
The motor system serves multiple functions: it provides the primary tension force, adjusts tension levels dynamically, maintains constant tension during movement, and can potentially provide resistance in both directions. This multi-functionality consolidates what would otherwise require separate mechanical components into a single integrated actuator system.
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 precise control of tension to mimic different muscle contraction patterns, enhancing the effectiveness of exercises by adjusting load resistance in real-time, allowing for varied muscle stimulation and improved workout experience.
Implementation Method 1
The string may be connected to an elastic member comprising an elastic material (e.g., an elastic band), and a tension may be applied to the string using the elastic member
Data Source
AI summary
To control tension of a string of a tension control apparatus, a target operation mode of the tension control apparatus may be received, a first tension value may be generated by measuring tension of a string connected to a sensor using the sensor, a first control signal for controlling a motor connected to the string may be generated based on the first tension value and the target operation mode, and tension of the string may be controlled by controlling the motor based on the first control signal.