Rotary Input Control With Electropermanent Resistance Switching
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Solution Overview
Problem
Existing physical computer peripheral interface devices, such as scroll wheels, lack efficient mechanisms for switching between different resistance profiles, affecting power usage, noise, user feel, and actuation time.
Innovation Solution
The use of an electropermanent magnet assembly with a magnetizing device and a permanent magnet, along with a control system to modulate electrical energy, changes the magnetic flux and resistance profile of a rotary input control, enabling efficient switching between resistance profiles, including free-wheeling and ratcheting modes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If traditional electromagnetic actuators are used to switch resistance profiles, then resistance profile switching is achieved, but power consumption increases and device complexity increases
Solution Approach 1:
The patent replaces traditional electromagnetic actuators with an electropermanent magnet assembly that uses electropermanent magnets instead of continuous electromagnetic coils. This substitution reduces power consumption because electropermanent magnets maintain their magnetic state without continuous electrical power, only requiring brief pulses to switch states. The electropermanent magnet assembly includes a permanent magnet, electropermanent magnets with magnetizing coils, and ferritic substrates with teeth that interact with the wheel teeth to generate resistance profiles.
Solution Approach 2:
The patent changes the magnetic properties of the electropermanent magnets by applying brief magnetizing pulses that flip the magnetic polarity of the electropermanent magnets between opposite directions. This parameter change (magnetic polarity) allows switching between different resistance profiles (ratcheting, free-wheeling, biased) without continuous power application. The control system monitors wheel rotation direction and applies magnetizing pulses at appropriate times to achieve desired resistance characteristics.
2Adaptability or versatility
If traditional electromagnetic actuators are used to switch resistance profiles, then resistance profile switching is achieved, but device complexity and number of components increases
Solution Approach 1:
The patent merges multiple functions into the electropermanent magnet assembly: the permanent magnet provides baseline magnetic field, the electropermanent magnets provide switchable magnetic fields for resistance profile control, and the ferritic substrates with teeth provide mechanical interaction with the wheel. This consolidation into a single integrated assembly reduces overall device complexity compared to using separate electromagnetic actuators for each resistance profile control function.
Solution Approach 2:
The electropermanent magnet assembly serves multiple functions: it generates ratcheting resistance profiles, free-wheeling resistance profiles, and biased resistance profiles by simply changing the magnetic polarity state of the electropermanent magnets. The same physical assembly handles all resistance profile switching without requiring additional actuators or mechanisms, making the system more versatile while maintaining simplicity.
3Reliability
If magnetic flux is increased to improve resistance profile switching, then switching reliability improves, but energy consumption increases
Solution Approach 1:
The patent uses periodic, pulsed magnetic fields from the magnetizing coils instead of continuous magnetic fields. Brief magnetizing pulses are applied at specific moments (when the wheel is stationary or changing direction) to flip the polarity of electropermanent magnets. This periodic action achieves reliable switching while minimizing energy consumption, as the coils are energized only momentarily rather than continuously.
Solution Approach 2:
The control system applies magnetizing pulses in advance of when resistance profile changes are needed, preparing the electropermanent magnets for upcoming switching events. By monitoring wheel rotation state and predicting when resistance profile changes will be required, the system applies magnetic flux preliminarily to ensure reliable switching occurs at the optimal moment without excessive energy waste.
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 allows for energy-efficient and reliable changes in the feedback response of rotary input controls, improving user interaction by varying resistance profiles based on user preferences and application needs, enhancing power usage, noise characteristics, and actuation time.
Implementation Method 1
a permanent magnet coupled to the magnetizing device and emitting a magnetic field
Implementation Method 2
the magnetic field having a first polarity in both the first and second states
Implementation Method 3
an electropermanent magnet assembly, comprising: a magnetizing device, and a permanent magnet coupled to the magnetizing device
Data Source
AI summary
A user input device that includes a rotary input control is described herein. The rotary input control includes first and second ferritic substrates; first and second permanent magnets extending between the first and second ferritic substrates to form a magnetic circuit; one or more magnetizing coils wrapped around the first permanent magnet; and a wheel defining a central volume within which the first and second ferritic substrates, the first and second permanent magnets and the one or more magnetizing coils are positioned. The user input device also includes a control system configured to direct current to the one or more magnetization coils to change a magnetization of the first permanent magnet to adjust a resistance profile of the rotary input control.