Piezo Haptic Actuator with Rigid Frame for Large Touchscreens
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Solution Overview
Problem
Current haptic systems for large touch-sensitive displays, such as those used in aircraft cockpits, struggle to provide effective force feedback due to insufficient actuator force and resonance frequency, making it difficult to simulate realistic button presses and kinesthetic effects, especially in noisy environments.
Innovation Solution
A haptic interaction device comprising a rigid assembly with a touch surface and frame, coupled with amplified piezoelectric actuators that generate significant reaction forces and resonate at frequencies matching the sensitivity of Pacinian receptors, allowing for realistic simulation of button presses and dynamic objects.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If traditional actuators (REM, RSM, electromagnetic, bimorph piezo) are used on large touchscreens, then the system can provide tactile feedback, but the actuators produce very low normal forces on the screen, far less than what an operator can produce
Solution Approach 1:
The system segments the actuator function by separating the force generation (piezoelectric element) from the motion amplification (mechanical linkage with pivot point). Multiple segmented actuators can be distributed across the touchscreen surface, each providing localized force feedback without requiring a single complex high-force actuator system
Solution Approach 2:
A mechanical intermediary structure (linkage with pivot point) is introduced between the piezoelectric actuator and the touchscreen surface. This intermediary amplifies the displacement while the piezoelectric material provides the necessary force, resolving the contradiction between force generation and motion range
2Force
If the number of actuators is increased to provide sufficient force feedback on large screens, then the force coverage improves, but the price, consumption, size and weight of the system increase
Solution Approach 1:
The system uses multiple segmented actuators distributed across the touchscreen, each providing localized force feedback. This segmentation allows the total force to be distributed across several lightweight units rather than requiring one or two heavy actuators, reducing overall system weight while maintaining adequate force coverage
Solution Approach 2:
The system changes the operating parameters by using piezoelectric materials with high force density and designing mechanical linkages with optimal leverage ratios. This allows achieving sufficient force amplification with smaller, lighter actuators compared to traditional electromagnetic or REM actuators
3Area of stationary object
If large touchscreens with diagonal of at least 15 inches are used, then the display area increases, but the resonance frequencies become low, making it difficult to generate vibro-tactile effects at frequencies sensitive to Pacinian receptors
Solution Approach 1:
The large touchscreen is segmented into multiple zones, each with its own actuator and mechanical linkage system. This segmentation creates multiple independent resonant systems, each capable of operating at higher frequencies suitable for Pacinian receptor sensitivity, rather than relying on the low-frequency resonance of the entire large screen as a single system
Solution Approach 2:
The system employs mechanical vibration through piezoelectric actuators coupled with mechanical linkages that can generate vibrations at frequencies matching Pacinian receptor sensitivity (150-250 Hz). The mechanical linkage design optimizes the transmission of high-frequency vibrations to the touchscreen surface despite the large screen area
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 enables realistic force feedback on large touch-sensitive surfaces, enhancing user interaction by simulating a wide variety of force effects and reducing power consumption, effectively addressing the limitations of existing systems in noisy environments.
Implementation Method 1
an actuator capable of generating a reaction force as a function of said input data
Implementation Method 2
the resonant frequency of said actuator being substantially equal to the resonant frequency of said rigid assembly
Data Source
Figure 1~2
Figure 3
AI summary
The assembly has a flat tactile surface (1) generating input data when the tactile surface is in contact with an activating system. A frame (2) is fixed on a periphery of the tactile surface. The tactile surface and the frame are arranged to from a rigid assembly (1-2). A piezoelectric actuator (3) is directly coupled with the frame for displacing the rigid assembly with respect to a support (4). Resonance frequency of the actuator is equal to resonance frequency of the rigid assembly.