Steering Wheel Hand Detection Using Rectangular Excitation Signals
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Solution Overview
Problem
Existing hands-on detection systems for semi-autonomous or fully autonomous driving are complex and require sophisticated hardware, including sine wave generators and oscillators, which increases the cost and complexity of the system.
Innovation Solution
A simplified hand detection apparatus for a steering wheel device that uses a periodic excitation signal, specifically a rectangular signal, generated by a digital data processing device, which is coupled to a conductive sensor portion integrated into the steering wheel. The system includes a signal recognition device to recognize the response signal and an evaluation device to determine changes in sensor capacitance based on the phase shift between the excitation and response signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional sine wave generators and oscillators are used for hand detection, then detection accuracy is maintained, but device complexity and cost increase
Solution Approach 1:
The patent changes the signal type parameter from sinusoidal to rectangular wave, and modifies the measurement approach by using phase shift detection between excitation and response signals. This allows accurate hand detection using simpler digital circuitry that generates rectangular waves instead of requiring complex sine wave generators and oscillators, thereby reducing device complexity while maintaining detection accuracy
Solution Approach 2:
The patent replaces the traditional analog sine wave generation mechanism with a digital rectangular wave generation approach. By using digital logic circuits to generate rectangular excitation signals and detecting phase shifts in the response, the system substitutes complex analog signal generation with simpler digital processing, reducing hardware complexity while preserving measurement precision
2Measurement precision
If traditional sine wave generators and oscillators are used for hand detection, then detection accuracy is maintained, but manufacturing cost increases
Solution Approach 1:
The patent changes the signal type parameter from sinusoidal to rectangular wave, and modifies the measurement approach by using phase shift detection between excitation and response signals. This allows accurate hand detection using simpler digital circuitry that generates rectangular waves instead of requiring complex sine wave generators and oscillators, thereby reducing device complexity while maintaining detection accuracy
Solution Approach 2:
The patent employs inexpensive digital logic components and standard microcontroller units that can generate rectangular waves and perform phase shift detection, replacing expensive precision analog signal generators. This substitution with cheaper, more readily available components reduces manufacturing cost while maintaining the required detection functionality and accuracy
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 significantly simplifies the structure of the hand detection apparatus, reducing hardware complexity and costs while maintaining effective detection of hands on the steering wheel, thereby enhancing safety and reducing operational expenses.
Implementation Method 1
determine a change in a sensor capacitance caused by at least one hand being placed on and/or removed from the steering wheel device
Data Source
AI summary
In the field of the semi-autonomous or fully autonomous driving, it is important to be able to monitor whether a driver is holding a steering wheel with their hand or whether the driver is leaving the steering wheel unattended. Hands-on detection/HOD systems are now often installed and involve measuring a capacitance which changes when at least one hand is placed on the steering wheel. The invention relates to a hand detection apparatus 1 for a steering wheel device 2 of a vehicle comprising: a sensor layer 7, the sensor layer 7 having at least one conductive sensor portion 9; a signal generator device 15, the signal generator device 15 being designed to generate an excitation signal 22 and being coupled to the sensor layer 7 in order to transfer the excitation signal 22 to the sensor layer 7; a signal recognition device 16 for recognizing a response signal 23, in response to the excitation signal 22, from the sensor layer 7, the signal generator device 16 being coupled to the sensor layer 7 in order to transfer the response signal 23 to the signal recognition device 16; an evaluation device 17, the evaluation device 17 being designed to determine a change in a sensor capacitance 19 caused by at least one hand being placed on and/or removed from the steering wheel device 2 on the basis of the recognized response signal 23 and the signal generator device 15 being designed to generate a rectangular signal as the excitation signal 22.