Haptic Interface Actuator Control for Multi-Point Tactile Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing haptic interfaces struggle to provide clear tactile sensations when multiple fingers or users are in contact with the same surface, as existing systems require a high number of actuators, leading to complexity and inefficiency, particularly in exploiting vibrational phenomena which are sensitive to environmental conditions and energy inefficient.
Innovation Solution
A haptic interface with a limited number of actuators that generates movements on a rigid touch screen portion except at neutral points, using a computer program to calculate instantaneous forces and control actuators to provide distinct tactile sensations at multiple points, allowing for simultaneous tactile feedback for multiple fingers or users.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If vibration phenomena are exploited to generate different simultaneous vibrations in several areas of the touch screen, then tactile sensations can be generated in multiple areas, but the system becomes sensitive to environmental conditions and boundary conditions
Solution Approach 1:
The patent applies mechanical vibration by exciting specific vibration modes of the touch screen to generate tactile sensations. By selectively exciting certain vibration modes, the system creates constructive and destructive interference patterns that produce localized vibration areas, enabling multi-area tactile feedback without requiring multiple actuators.
Solution Approach 2:
The system changes vibration parameters (frequency, mode selection, amplitude distribution) to control where tactile sensations occur on the screen. By adjusting these parameters, the same physical touch screen can generate different vibration patterns in different areas, achieving adaptability without adding physical components.
2Adaptability or versatility
If a large number of actuators are used to provide tactile sensations across the entire contact surface, then tactile feedback is available everywhere, but the system complexity and control difficulty increase greatly
Solution Approach 1:
The touch screen serves multiple functions: it acts as both the display surface and the vibration medium for generating tactile sensations. By utilizing the screen's inherent vibrational properties, the system eliminates the need for separate actuators at each location, reducing component count while maintaining full-surface tactile capability.
Solution Approach 2:
Instead of placing physical actuators at every location, the system creates virtual actuators through controlled vibration patterns. The vibration modes effectively 'copy' the function of multiple physical actuators using a single integrated surface, reducing hardware complexity while achieving the same functional outcome.
3Measurement precision
If vibration exciters are used to apply flexural waves to maximize amplitude at the touched sensing area, then tactile sensation is enhanced at the contact point, but energy efficiency decreases
Solution Approach 1:
The system uses periodic vibration excitation at specific frequencies that resonate with the touch screen's natural modes. By applying energy at these resonant frequencies, the system achieves maximum vibration amplitude with minimal energy input, improving energy efficiency compared to non-resonant excitation methods.
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 enables efficient generation of tactile sensations across a touch screen surface for multiple fingers or users, reducing the complexity and energy consumption associated with traditional systems, while maintaining sensitivity and accuracy.
Implementation Method 1
These systems generally comprise several actuators fixed on a touch screen so as to move the touch screen by small rapid movements
Implementation Method 2
consists of causing constructive and destructive interference in areas of the touch screen by selectively exciting certain vibration modes
Implementation Method 3
a panel capable of supporting flexural waves, a touchscreen accessible to the user and having a plurality of different sensing areas
Implementation Method 4
consists of using the principle of time reversal to refocus the waves resulting from the impulse responses measured at different points on the touch screen
Data Source
Figure 1~2
Figure 3~5
AI summary
The invention relates to a method for generating a tactile sensation intended to be felt by a user (200) in contact with a surface of a rigid portion (115) of a haptic interface (100), the method comprising an operation which consists of transmitting control signals for simultaneously controlling at least two actuators (120), which are integral with the rigid portion, so as to cause a movement (D) of the rigid portion, each of the control signals comprising an amplitude determined such that the movement subsides at a predefined neutral position (PN, LN) of the rigid portion, said neutral position being separate from a point of contact (PA) where the user is in contact with the surface of the rigid portion. The invention also relates to a haptic interface (100) implementing said method.