Electromagnetic Actuator with Ferromagnetic Core for Haptic Feedback
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Solution Overview
Problem
Existing touch-sensitive input devices with electromagnetic actuators face challenges in maintaining a consistent resting position due to varying elasticity and ambient conditions, requiring precise adjustment and potential readjustment over time.
Innovation Solution
A touch-sensitive input device with an electromagnetic actuator comprising a coil, ferromagnetic core, and armature, where the control electronics generate a limited electrical signal to achieve maximum magnetization of the armature, reducing the dependency on precise positioning and allowing for haptic feedback without the need for readjustment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If the electromagnetic actuator uses a coil and armature with a predetermined air gap, then the device structure is simple and installation space is saved, but the electromagnetic force varies starkly with distance making consistent resting position difficult to maintain
Solution Approach 1:
The patent changes the magnetic parameter by introducing a ferromagnetic core that concentrates and directs magnetic flux. This transforms the magnetic field distribution so that the armature experiences a stronger, more stable magnetic force that is less sensitive to air gap variations, thereby maintaining consistent resting position while keeping the simple coil-armature structure
Solution Approach 2:
The ferromagnetic core acts as an intermediary between the coil and the armature. It concentrates the magnetic flux generated by the coil and directs it toward the armature, creating a more stable magnetic interaction that reduces the sensitivity to distance variations while maintaining the simple overall structure
2Volume of moving object
If the elastic device is manufactured as stamped parts from spring steel to save installation space, then the device compactness is improved, but the elasticity varies with operating duration and ambient conditions affecting actuation consistency
Solution Approach 1:
The system uses the force sensor to detect actual actuation forces and the control electronics to automatically adjust actuator activation thresholds and haptic feedback parameters in real-time. This self-adjusting mechanism compensates for elasticity variations in the stamped spring steel components, maintaining consistent actuation behavior despite changes in elastic properties over time and temperature
3Manufacturing precision
If precise adjustment of the actuating element is performed during installation, then the initial actuation consistency is improved, but the device requires readjustment during operation due to elasticity variations and ambient conditions
Solution Approach 1:
The patent implements a feedback system where the force sensor continuously monitors actuation forces and the control electronics adjust the actuator's activation threshold and haptic feedback strength accordingly. This closed-loop control compensates for elasticity variations and ambient condition changes, maintaining consistent actuation without requiring manual readjustment during operation
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 solution provides a haptic feedback system that is less sensitive to variations in the resting position caused by aging or temperature changes, reducing the need for initial precise positioning and ensuring consistent actuation throughout the device's usage duration.
Implementation Method 1
an electromagnetic actuator (4) configured to act between the input part (2) and the support (3) so as to produce a deflection of the input part (2) out of a resting position
Implementation Method 2
The ferromagnetic core (5) is configured to generate a magnetic field defining a pole direction. The ferromagnetic armature (6) is configured to interact with the magnetic field.
Implementation Method 3
The electromagnetic actuator comprises a coil (7) which is configured to define a cavity, a ferromagnetic core (5) which is arranged at least in a region in the cavity
Implementation Method 4
an elastic device configured to bear the input part (2) at the support (3) along a deflection direction so that the input device is elastically reset
Data Source
AI summary
A touch-sensitive input device includes a support, an input part with a touch-sensitive input surface, an elastic device which bears the input part at the support, an electromagnetic actuator which acts between the input part and the support to produce a deflection of the input part out of a resting position, and control electronics. The electromagnetic actuator comprises a coil with a cavity, a core arranged at least in part in the cavity, and an armature arranged outside the cavity. The core generates a magnetic field defining a pole direction. The armature interacts with the magnetic field. The control electronics generate an electrical control signal for the coil to produce the deflection of the input part out of the resting position and to provide a maximum deflection of the input part. A duration of the electrical control signal is limited so as to provide, after the deflection, a haptic feedback.