Response Force Waveform Control for Heavy Operation Panels
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Solution Overview
Problem
Existing response force generation devices struggle to apply a large acceleration response force to operation panels with significant mass, as the vibration waveforms such as sine or rectangular waves often fail to provide sufficient force, and increasing the frequency of triangular waves can lead to difficulties in driver circuit frequency characteristics and voltage growth.
Innovation Solution
A response force generation device with a magnetic drive unit and a drive control unit that sets a drive waveform with a first section of increasing signal intensity and a second section with a lower increase rate, allowing for a peak voltage to be applied to the drive coil, enabling a high peak voltage and large acceleration force to be applied to the movable portion, even with a large mass operation panel.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the frequency of a drive waveform of a triangular wave is increased and a waveform of a peak portion of the triangular wave is set to a sharp shape, then it is difficult for the frequency characteristic of a driver circuit (power amplifier) provided in the operation panel vibration means to follow a change in the intensity of a peak region of the triangular wave, and a growth of a voltage acting on a drive coil is more likely to become stunted in the vicinity of the peak of the triangular wave
Solution Approach 1:
The patent applies parameter changes by modifying the drive waveform shape from a standard triangular wave to a trapezoidal wave with controlled rise and fall times. Specifically, the waveform parameters (rise time Tr and fall time Tf) are optimized to ensure they are not too short, allowing the driver circuit to track the waveform accurately without voltage stunting, while still achieving sufficient vibration frequency and response force acceleration.
2Speed
If the frequency of a drive waveform of a triangular wave is increased and a waveform of a peak portion of the triangular wave is set to a sharp shape, then it is difficult to apply a sufficient acceleration to a movable portion in a vibration generation unit due to the influence of an impedance of the drive coil provided in the vibration generation unit, an inertia force of the movable portion to be operated by the drive coil
Solution Approach 1:
The patent modifies the drive waveform parameters by using a trapezoidal wave with controlled rise and fall times instead of a sharp triangular wave. This parameter optimization ensures that the voltage can grow sufficiently during the ramp periods, overcoming the impedance and inertia effects, thereby achieving both sufficient acceleration and proper voltage growth without the conflicting sharp peak shape.
3Ease of operation
If a vibration waveform of a sine wave or a rectangular wave is used, then it is possible to make the finger touching the touch panel relatively easily feel a response force with respect to the pressing of the touch panel, but when it is desired to apply a large response force to the operation panel having a relatively large mass, or when it is desired to apply a large operation reaction force similar to a response force when a mechanical switch is pressed to an operating finger, the vibration waveform of the sine wave or the rectangular wave is often insufficient
Solution Approach 1:
The patent employs dynamics by using a trapezoidal wave drive waveform that provides high acceleration during the rise and fall phases, generating large response forces comparable to mechanical switches. This dynamic waveform shape maintains the perceptibility advantage of high-frequency vibrations while achieving the large force magnitude needed for heavy operation panels, thus resolving the contradiction between ease of operation and force magnitude.
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 the application of a sharp and large response force to the operating finger, similar to pressing a mechanical switch, by optimizing the drive waveform to improve the follow-up characteristics of the driver circuit and increase the kinetic energy applied to the movable portion, effectively addressing the limitations of previous technologies.
Implementation Method 1
a magnetic drive unit configured to operate the movable portion
Data Source
AI summary
A drive waveform setting unit sets a drive waveform of a drive signal, and a drive current is applied to a drive coil provided in a response force generation mechanism in accordance with the drive waveform. The drive waveform has a first drive section in which a signal intensity increases linearly and a second drive section including a peak. An increase rate of the signal intensity in the second drive section is lower than that in the first drive section. As a result, it is easy to follow the frequency characteristics of a driver circuit, and it is possible to increase a voltage to be applied to a drive coil.