MR Tether Tension Control for Payload Motion Isolation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current systems for dynamic motion control of tethered payloads face challenges in maintaining stable tension and minimizing the effects of unsteady aerodynamics and wind gusts, which can lead to undesirable payload motion.
Innovation Solution
The use of magnetorheological (MR) fluid actuator units with MR fluid clutch apparatuses to control the tension of tethers between an object and a load, allowing for precise adjustment of torque and tension based on sensor feedback from inertial and GPS sensors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If magnetorheological fluid actuators are used to control tether tension, then payload isolation from disturbances is improved, but device complexity increases
Solution Approach 1:
The patent replaces traditional mechanical actuators (motors, winches) with magnetorheological fluid actuators that use magnetic field control to adjust tether tension. This substitution enables precise, rapid tension modulation without complex mechanical transmission systems, improving payload isolation while actually reducing mechanical complexity.
Solution Approach 2:
The magnetorheological fluid actuator changes the physical state of the fluid (from liquid-like to semi-solid) by adjusting magnetic field strength, which directly controls tether tension. This parameter-based control allows dynamic adaptation to disturbances without mechanical reconfiguration, resolving the contradiction between reliability and complexity.
2Stability of the object's composition
If tension control is implemented to minimize payload motion, then stability is improved, but use of energy increases
Solution Approach 1:
The control system uses periodic adjustments of tether tension based on detected payload deviations, rather than continuous energy-consuming actuation. The magnetorheological fluid maintains tension states by holding magnetic field configurations, reducing continuous energy input requirements while maintaining stability.
Solution Approach 2:
The magnetorheological fluid actuator maintains its magnetic field configuration and corresponding tether tension without continuous external energy input once activated. The system uses feedback from sensors to make self-correcting adjustments, minimizing energy consumption while maintaining payload stability.
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 solution enables effective isolation of the payload from unwanted motion caused by aircraft dynamics or wind disturbances, maintaining stable tension and improving the control of payload position and acceleration.
Implementation Method 1
at least one magnetorheological (MR) fluid actuator unit including at least one torque source and at least one MR fluid clutch apparatus coupled to the at least one torque source to receive torque from the at least one torque source
Data Source
AI summary
A system for controlling a tension of a tether between an object and a load tethered to the object comprises magnetorheological (MR) fluid actuator unit(s) including at least one torque source and at least one MR fluid clutch apparatus coupled to the at least one torque source to receive torque from the at least one torque source, the MR fluid clutch apparatus controllable to transmit a variable amount of torque via an output of the MR fluid actuator unit. A tensioning member is connected to the output so as to be pulled by the output member upon actuation of the magnetorheological fluid clutch apparatus, a free end of the tensioning member adapted to exert a pulling action when being pulled by the output member. Sensor(s) provide information indicative of a relation between the object and the load tethered to the object. A controller controls the at least one MR fluid clutch apparatus in exerting the pulling action based on said information.