Haptic System Calibration with Phyllotactic Arrays for Ghost Reduction
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Solution Overview
Problem
Existing haptic systems face challenges in controlling acoustic fields due to erroneous local maxima, which cause secondary effects and ghost phenomena, and manual calibration is prone to human error.
Innovation Solution
Implementing transducer arrays with phyllotactic spiral patterns and computational automation to optimize transducer placement, combined with levitation fiducials for automated calibration, to minimize secondary maxima and improve haptic feedback accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If transducer arrays are arranged in conventional patterns (rectilinear, hexagonal, random), then manufacturing and layout are simplified, but erroneous local maxima and ghost phenomena occur in the acoustic field
Solution Approach 1:
The patent applies asymmetry by using a phyllotactic spiral pattern for transducer arrangement, which is inherently asymmetric and irrational. This asymmetric configuration prevents the formation of regular interference patterns that cause ghost phenomena and erroneous local maxima, while still being manufacturable through automated placement systems.
Solution Approach 2:
The patent changes the arrangement parameters from conventional geometric patterns (rectilinear, hexagonal) to a phyllotactic spiral pattern defined by irrational mathematical relationships. This parameter change transforms the transducer distribution from periodic to aperiodic, eliminating the harmful interference patterns while maintaining manufacturing feasibility.
2Object-affected harmful factors
If ideal phyllotactic spiral patterns are implemented, then erroneous local maxima are minimized, but physical manufacturing and production constraints make exact implementation difficult
Solution Approach 1:
The patent applies preliminary action by pre-calculating the ideal phyllotactic spiral positions using mathematical formulas before manufacturing. These pre-calculated positions serve as target coordinates for automated transducer placement, allowing the system to achieve close approximation of the ideal pattern while accounting for manufacturing tolerances.
Solution Approach 2:
The patent uses copying by creating a digital model or map of the ideal phyllotactic spiral pattern, which then guides the physical placement of transducers. This digital copy allows for precise calculation of positions and facilitates automated manufacturing processes that can reproduce the pattern with high fidelity despite physical constraints.
3Device complexity
If manual calibration is performed to establish correspondence between acoustic field coordinate space and sensor coordinate space, then calibration can be done with simple equipment, but human error and subjectivity increase
Solution Approach 1:
The patent applies self-service by implementing an automated calibration system that performs coordinate space correspondence establishment without human intervention. The system uses fiducial markers and computational algorithms to automatically determine the transformation between acoustic field coordinates and sensor coordinates, eliminating human error while maintaining equipment simplicity.
Solution Approach 2:
The patent replaces the manual mechanical calibration process with an automated computational system. Instead of relying on human operators to physically adjust and measure, the system uses digital image processing, coordinate transformation algorithms, and automated feedback to establish accurate correspondence between coordinate spaces.
4Measurement precision
If automated approaches are used for transducer placement and calibration, then human error is reduced, but system complexity and computational requirements increase
Solution Approach 1:
The patent applies universality by designing the automated calibration system to perform multiple functions: fiducial marker detection, coordinate transformation calculation, and validation. This multi-functional approach consolidates what could be separate complex subsystems into a unified calibration module, reducing overall system complexity while maintaining high precision.
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 phyllotactic spiral patterns effectively reduce secondary maxima, enhance haptic feedback quality, and automate the calibration process, reducing human error and improving the efficiency of haptic systems.
Implementation Method 1
levitation fiducials for automated calibration
Data Source
AI summary
A system providing various improved calibration techniques for haptic feedback is described. An acoustic field is defined by one or more control points in a space within which the acoustic field may exist. Each control point is assigned an amplitude value equating to a desired amplitude of the acoustic field at the control point. Because complete control of space is not possible, controlling the acoustic field at given points yields erroneous local maxima in the acoustic field levels at other related positions. In relation to mid-air haptic feedback, these can interfere in interactions with the space by creating secondary effects and ghost phenomena that can be felt outside the interaction area. The level and nature of the secondary maxima in the acoustic field is determined by how the space is controlled. By arranging the transducer elements in different ways, unwanted effects on the acoustic field can be limited and controlled.