Electropermanent Magnet Clutch Assembly for Low-Power Torque Control
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Solution Overview
Problem
Existing clutch mechanisms using magnetorheological fluids face significant power consumption issues due to the need for continuous current to maintain magnetic fields, limiting their application in untethered and remote operations.
Innovation Solution
The use of electropermanent magnets (EPMs) to control the magnetic fields in magnetorheological fluids, allowing for low-power, selectively modulated torque transfer by transitioning between on, off, and intermediate states, reducing power consumption and enabling efficient torque control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If continuous current is used to maintain magnetic fields in magnetorheological fluids, then torque transfer capability is maintained, but power consumption increases significantly
Solution Approach 1:
The patent employs periodic pulsed current instead of continuous current to maintain magnetic fields in magnetorheological fluids. The system applies current in periodic pulses that are sufficient to maintain the desired torque transfer capability while allowing the system to enter low-power states between pulses, thereby significantly reducing overall power consumption while maintaining reliability
Solution Approach 2:
The patent changes the temporal parameter of current application from continuous to pulsed/intermittent. By modifying the duty cycle, pulse width, and amplitude of current application, the system maintains adequate magnetic field strength for torque transfer while reducing average power consumption through parameter optimization
2Use of energy by moving object
If electropermanent magnets are used to reduce power consumption, then energy efficiency improves, but device complexity increases due to additional control mechanisms
Solution Approach 1:
The electropermanent magnets in the patent utilize permanent magnet materials that maintain their magnetic field without requiring continuous external energy input. The magnets essentially serve themselves by maintaining residual magnetism, requiring only brief pulsed current to switch or adjust states, thereby achieving high energy efficiency with minimal control complexity
Solution Approach 2:
The patent extracts the continuous power requirement from the system by using electropermanent magnets that maintain their magnetic field independently once activated. This separates the field maintenance function from continuous power supply, reducing overall system complexity while improving energy efficiency
3Adaptability or versatility
If variable torque transfer characteristics are implemented, then adaptability improves, but control system complexity increases
Solution Approach 1:
The patent implements dynamic torque transfer characteristics by enabling real-time adjustment of magnetic field strength through pulsed current control of electropermanent magnets. The system can dynamically vary torque capacity in response to operational requirements while using relatively simple control logic based on pulse timing and amplitude rather than complex continuous control systems
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
EPMs provide energy-efficient, programmable, and compact clutch assemblies that can dynamically vary torque transfer characteristics, suitable for untethered and remote operations, enhancing the utility of magnetorheological fluid-based systems.
Implementation Method 1
one or more electropermanent magnets (EPMs). Each EPM is configured to generate a respective EPM magnetic field that extends through the clutch body
Implementation Method 2
Each EPM is configured to generate a respective EPM magnetic field that extends through the clutch body
Implementation Method 3
a clutch body enclosing a torque transfer fluid... controlling each of one or more EPMs of the clutch assembly to vary a total EPM magnetic flux generated by the one or more EPMs and extending through a magnetorheological fluid of the clutch assembly
Data Source
AI summary
Clutch assemblies and associated methods are disclosed herein. In an example, a clutch assembly comprise a first terminal, a second terminal, a clutch body enclosing a torque transfer fluid, and one or more electropermanent magnets (EPMs), each configured to generate a respective EPM magnetic field. The clutch assembly is configured to transmit a torque between the first terminal and the second terminal with a torque capacity that is at least partially based on the EPM magnetic fields. In an example, a method of operating a clutch assembly comprises transitioning each of one or more EPMs to a fully depolarized state, a fully polarized state, or an intermediate polarization state. In an example, a method of operating a clutch assembly comprises controlling each of one or more EPMs of the clutch assembly to vary a total EPM magnetic flux generated by the one or more EPMs.