MR Fluid Clutch Control for Slippage and Torque Transmission
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Solution Overview
Problem
Current distributed power devices rely on hydraulic or electromagnetic actuation, which face limitations such as mechanical jamming, dynamic response, efficiency, and maintenance costs, with electromagnetic actuation systems being heavy and having high output inertia, friction, and backlash.
Innovation Solution
A control system for magnetorheological (MR) fluid clutch apparatuses that includes a clutch driver for controlled slippage and combined modes, a motor driver, a mode selector module, and a movement controller to manage slippage and motor output based on movement parameters, enabling efficient torque transmission and dynamic performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If hydraulic actuation is used, then reliability is improved, but device complexity and maintenance costs increase
Solution Approach 1:
The patent replaces hydraulic actuation systems with magnetorheological fluid-based electromechanical actuation. The MR fluid clutch apparatus uses magnetic fields to control fluid viscosity and torque transmission, eliminating hydraulic pumps, reservoirs, and complex fluid delivery systems while maintaining reliable torque control without the maintenance issues of hydraulic leakage.
Solution Approach 2:
The patent changes the physical state and properties of the MR fluid through magnetic field application. By varying the magnetic flux density, the system dynamically adjusts the yield shear stress and viscosity of the MR fluid, enabling continuous torque control without mechanical adjustments or complex control mechanisms.
2Speed
If direct-drive motors are used, then dynamic performance is improved, but weight increases
Solution Approach 1:
The patent segments the actuation system into a lightweight MR fluid clutch apparatus that provides precise torque control and a separate motor system. This allows the use of smaller, lighter motors compared to direct-drive configurations while maintaining high dynamic performance through the responsive MR fluid torque transmission.
Solution Approach 2:
The patent uses magnetorheological fluid, a composite material consisting of magnetizable particles suspended in a carrier fluid. This composite material enables the clutch to achieve high torque density and rapid response characteristics typically associated with heavier direct-drive systems, while maintaining lighter overall weight.
3Weight of moving object
If reduction gearboxes are used, then weight is reduced, but friction and backlash increase
Solution Approach 1:
The patent substitutes traditional mechanical reduction gearboxes with an electromagnetic-MR fluid hybrid system. The motor provides rotational motion, and the MR fluid clutch apparatus provides torque multiplication and control without mechanical gear engagement, thereby eliminating gear friction and backlash while keeping the system lightweight.
Solution Approach 2:
The patent dynamically changes the torque transmission characteristics of the MR fluid clutch by adjusting the magnetic field strength. This allows the system to achieve effective torque multiplication without fixed mechanical gear ratios, eliminating the friction and backlash inherent in traditional reduction gearboxes while maintaining weight advantages.
4Power
If high torque is transmitted through MR fluid clutch, then power transmission capability is improved, but energy dissipation increases
Solution Approach 1:
The patent dynamically adjusts the magnetic flux density in the MR fluid clutch apparatus based on the required torque transmission. By varying the magnetic field strength in real-time, the system optimizes the yield shear stress of the MR fluid to match the instantaneous torque demands, minimizing energy dissipation through unnecessary viscous resistance while maintaining high power transmission capability when needed.
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
The system enhances the dynamic performance and reduces energy dissipation in MR fluid clutch apparatuses, improving the efficiency and reliability of electromechanical actuation systems by managing slippage and torque transmission effectively.
Implementation Method 1
magnetorheological (MR) fluid clutch apparatus... the apparent yield shear stress of the MR fluid in the interface between the input and the output of the MR fluid clutch apparatus controls the torque transmitted
Implementation Method 2
the MR fluid absorbs energy that may be proportional to the speed difference and the torque transmitted from the input to the output
Data Source
AI summary
A control system for controlling movements of an end effector connected to a clutch output of magnetorheological (MR) fluid clutch apparatuses. A clutch driver drives the MR fluid clutch apparatuses between a controlled slippage mode, in which slippage in the MR fluid clutch apparatuses varies, and a combined mode, in which slippage between clutch input and clutch output is maintained below a given threshold simultaneously for both of the MR fluid clutch apparatuses, the two clutch outputs resisting movement of the end effector in the same direction. A mode selector module receives signals representative of a movement parameter(s) of the end effector, to select and switch a mode based on the signals. A movement controller controls the clutch driver and the motor driver to displace the end effector based on the selected mode and on commanded movements of the end effector for the end effector to achieve the commanded movements.