Input Device Magneto-Rheological Braking Torque Control
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Solution Overview
Problem
Existing input devices face challenges in providing stable sensations of resistance and retraction while minimizing power consumption and avoiding undesirable vibrations, as they often require complex motor control and increased power usage to maintain non-operating states.
Innovation Solution
An input device incorporating a holding section, a rotating body, a rotation detection unit, a brake-applying unit with magneto-rheological fluid, and a torque-applying unit with controlled coils to apply resistance and pull-in torques, allowing for precise control of rotation sensations and reduced power consumption by stopping torque-applying unit operation during braking.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a motor is used to apply rotational force to provide resistance and acceleration sensations, then the sensations can be provided to the operator, but the control becomes complex and undesirable vibration may be generated
Solution Approach 1:
The patent replaces the motor-driven mechanical system with a magnetic field-based system. The brake-applying coil generates a magnetic field that acts on the magnetic-field responsive material to apply braking force, while the torque-applying coils generate magnetic fields to apply rotational torque. This substitution eliminates the need for mechanical motors and complex control mechanisms, simplifying the overall control system while maintaining the ability to provide resistance and acceleration sensations.
Solution Approach 2:
The patent utilizes changes in the physical properties of the magnetic-field responsive material based on magnetic field intensity. When no magnetic field is generated, the viscosity or shearing flow resistance decreases, allowing easy rotation. When a magnetic field is generated, the viscosity or shear flow resistance increases, providing braking force. This parameter change approach enables dynamic control of operation sensations without complex mechanical systems.
2Reliability
If the motor is energized to keep the operating member stationary in non-operating state, then the member does not move, but power consumption increases
Solution Approach 1:
The patent employs periodic or conditional activation of the brake-applying coil rather than continuous energization. The coil is energized only when braking force is needed (e.g., when the operating member approaches a stop position or when position stability is required), and de-energized during normal operation. This periodic action maintains position stability when needed while significantly reducing overall power consumption compared to continuous motor energization.
3Force
If the brake uses magnetic-field responsive material to apply braking force, then braking is effective, but rotational force cannot be applied and various operation sensations cannot be provided
Solution Approach 1:
The patent divides the electromagnetic system into functionally independent segments: the brake-applying coil for generating braking force through magnetic-field responsive material, and separate torque-applying coils for generating rotational torque. This segmentation allows each component to perform its specific function effectively while working together to provide diverse operation sensations including resistance, acceleration, and various tactile feedbacks.
Solution Approach 2:
The magnetic field system serves multiple functions: the brake-applying coil provides braking force, while the torque-applying coils provide rotational torque for resistance and acceleration sensations. By integrating these functions into a unified magnetic field-based system rather than using separate mechanical components, the patent achieves versatility in operation sensations while maintaining effective braking capability.
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 device effectively provides stable resistance and retraction sensations with reduced power consumption by controlling the magneto-rheological fluid and torque-applying coils, minimizing vibrations and optimizing power usage.
Implementation Method 1
a magneto rheological fluid provided in a gap between the holding section and the rotary plate, and the brake-applying coil configured to provide a magnetic field to the magneto rheological fluid
Implementation Method 2
the torque-applying unit includes the at least two torque-applying coils configured to apply a rotation torque to the rotating body
Data Source
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AI summary
A rotating body (10) is rotatably supported on a holding section (2). The holding section (2) includes a rotation detection unit (20), a torque-applying unit (30), and a brake-applying unit (40). The torque-applying unit (30) includes an A-phase torque-applying coil (36A) and a B-phase torque-applying coil (36B), and a resistance torque and a pull-in torque applied to a rotor (magnet) (13) are caused to vary as a result of controlling supply of current to each of the coils (36A, 36B). In addition, a braking force can be controlled by supplying current to a brake-applying coil (47) included in the brake-applying unit (40).