Variable Impedance Touch Array for Steering Wheel Pressure Sensing
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Solution Overview
Problem
Existing automotive touch sensor systems lack the ability to accurately detect proximity, contact, and pressure with sufficient spatial resolution and precision, particularly in dynamic environments like a vehicle dashboard or steering wheel, where multiple inputs can confuse traditional sensors.
Innovation Solution
The use of an interpolated variable impedance touch sensor array that couples interlinked impedance columns and rows with a column and row switching register to accurately detect touch, pressure, and spatial location through current/voltage interpolation, allowing for precise control and gesture recognition.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional touch sensors are used in automotive applications, then the system structure is simple, but the measurement precision and spatial resolution are insufficient for accurate touch and pressure detection
Solution Approach 1:
The touch sensor surface is divided into multiple sensing elements arranged in rows and columns, creating a matrix array that provides spatial resolution. Each sensing element independently detects touch and pressure, enabling precise location identification while maintaining a relatively simple overall structure through the systematic arrangement of identical elements.
Solution Approach 2:
The patent transitions from single-point or simple linear touch detection to a two-dimensional matrix array of sensing elements. This dimensional expansion allows simultaneous detection of touch location (x,y coordinates) and pressure magnitude across the surface, significantly improving spatial resolution without proportionally increasing system complexity.
2Reliability
If traditional touch sensors are used, then the device complexity is low, but the reliability is insufficient to distinguish multiple inputs and reduce false detections in dynamic environments
Solution Approach 1:
By segmenting the touch surface into multiple sensing elements arranged in rows and columns, the system can distinguish between multiple simultaneous touch inputs at different locations. The matrix structure allows independent monitoring of each sensing element, enabling reliable differentiation of genuine user inputs from false detections caused by environmental factors or accidental contacts.
3Measurement precision
If high spatial resolution touch detection is implemented, then measurement precision improves, but the device complexity increases due to additional sensors and processing requirements
Solution Approach 1:
The patent combines multiple sensing elements into an integrated matrix array that shares common row and column conductors. This merging approach allows simultaneous operation of numerous sensing elements while using a relatively small number of physical conductors, reducing the complexity of wiring and signal processing compared to having completely independent sensors for each measurement point.
Solution Approach 2:
Each sensing element in the matrix array serves multiple functions: detecting touch presence, measuring pressure magnitude, and providing spatial location information. The row and column conductors serve dual purposes of both stimulating the sensing elements and reading their responses. This multi-functionality reduces the overall system complexity while maintaining high measurement 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
Enables accurate detection of touch, pressure, and spatial location with continuous pressure gradients, reducing false inputs and enhancing user interaction by allowing intuitive control of vehicle functions without visual distraction.
Implementation Method 1
a variable impedance array electrically coupling interlinked impedance columns coupled to an array column driver and interlinked impedance rows coupled to an array row sensor
Implementation Method 2
electrically drive the interlinked impedance columns using a column driving source
Data Source
AI summary
The present invention relates to automotive interface systems and methods. In one embodiment, an automotive interface system includes a steering wheel and an integrated interpolated variable impedance array that comprises a grid of sensing elements. The sensing elements are configured to power on simultaneously and to simultaneously generate multiple currents along multiple current paths in response to sensing a touch wherein the amount of current generated by a sensing element of the grid is directly proportional to the force applied by the touch. The automotive interface system also includes an analog-to-digital converter (ADC) and a processor communicatively coupled to the interpolated variable impedance array that are configured to receive the multiple currents along multiple current paths and determine a location, a duration, an area, and a force of the touch from the multiple currents along multiple current paths.