Electromagnetic Haptic Control for Harmonic-Free Vibration Decay
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Solution Overview
Problem
Existing haptic interface devices generate harmonics on acceleration waveforms due to square wave pulses applied to electromagnetic actuators, leading to uncomfortable touch operation feelings and abnormal noises.
Innovation Solution
A control device applies a main driving signal followed by a sub-driving signal with a variable voltage and sine or cosine function curve to adjust the vibration attenuation period, suppressing harmonic generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a square wave pulse is applied to the coil of the electromagnetic actuator to adjust the vibration attenuation period, then the vibration attenuation period can be extended or shortened, but a harmonic is superimposed on the acceleration waveform of vibration causing uncomfortable touch operation feeling and abnormal noise
Solution Approach 1:
The patent changes the waveform parameter from a square wave to a sine wave for the additional driving signal applied to the coil. This parameter change eliminates the harmonic components that are inherent in square wave signals, thereby suppressing the superimposition of harmonics on the vibration acceleration waveform while still achieving the desired adjustment of the vibration attenuation period.
2Duration of action of moving object
If a square wave pulse is applied to the coil, then the vibration attenuation period can be adjusted, but current variation at the time of application or stopping causes harmonic superimposition
Solution Approach 1:
The patent changes the waveform parameter from a square wave to a sine wave for the additional driving signal. This change ensures smooth current variation during application and stopping of the signal, eliminating the abrupt transitions that cause harmonic superimposition and improve the overall smoothness and reliability of the vibration output.
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 effectively suppresses harmonic generation during vibration attenuation, providing a more comfortable and noise-free touch operation experience.
Implementation Method 1
an electromagnetic actuator that drives an operation device, which is supported in an elastically vibratable manner by an elastic support part, in one direction of a vibration direction of the operation device to vibrate the operation device
Implementation Method 2
an operation device, which is supported in an elastically vibratable manner by an elastic support part
Data Source
AI summary
Provided is a control device controlling an electromagnetic actuator that drives an operation device, supported in an elastically vibratable manner by an elastic support part, in one direction of a vibration direction of the operation device to vibrate the operation device. The control device includes a circuit that applies a main driving signal to a coil of the electromagnetic actuator to start vibration of the operation device in response to a touch operation on the operation device, then applies a sub-driving signal to the coil to adjust an attenuation period of the vibration. The sub-driving signal has a variable voltage varying with an offset voltage, as a center value, offset from a zero voltage, and a waveform that indicates a variation in the variable voltage is a sine function curve or a cosine function curve.