Touch Detection Device Steering Wheel Noise Suppression
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Solution Overview
Problem
Existing touch detection devices for steering wheels face accuracy issues due to interference from electromagnetic waves emitted by mains electricity transmission lines, which vary in frequency between 50 Hz and 60 Hz, causing errors in detection.
Innovation Solution
A touch detection device that sets the measurement frequency to either 50 Hz or 60 Hz, calculates segment averages based on the measurement frequency, and adjusts the interval between averaging segments to ensure one segment average value suppresses the other, effectively removing power source frequency components from the averaged measurement values.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a filter employing electrical components (resistors, capacitors) is used to remove noise components, then detection accuracy is improved, but device size increases and installation becomes extremely difficult
Solution Approach 1:
The patent replaces physical electrical filters (mechanical/electrical components) with a software-based digital filtering system. The measurement control section performs digital signal processing to remove noise components from capacitance measurement values, eliminating the need for physical resistors, capacitors, and inductors that would increase device size and installation difficulty.
Solution Approach 2:
The patent introduces a measurement control section as an intermediary between the sensor electrode and the output, which processes the raw measurement values through digital filtering algorithms. This intermediary layer removes noise components computationally without requiring additional physical filtering components in the signal path.
2Object-affected harmful factors
If a digital filter is configured to remove 50 Hz frequency components, then 50 Hz interference is suppressed, but 60 Hz interference remains unaffected and vice versa
Solution Approach 1:
The patent designs the measurement control section with multi-functional capability to handle both 50 Hz and 60 Hz interference frequencies. The system can adaptively configure its filtering parameters based on the detected power source frequency, making a single device universally applicable across different regional electrical standards without requiring hardware changes.
Solution Approach 2:
The patent implements dynamic frequency adaptation where the measurement control section adjusts its operating parameters based on the detected power source frequency. The system determines whether the environment uses 50 Hz or 60 Hz power and dynamically configures the digital filter accordingly, transforming a static filter into an adaptive system that responds to environmental conditions.
3Object-affected harmful factors
If electromagnetic waves from transmission lines are present, then interference noise is generated in the electrostatic capacitance sensor, but no physical filter can be installed on the steering wheel
Solution Approach 1:
The patent replaces physical filtering components with software-based digital filtering implemented in the measurement control section. This substitution eliminates the need to physically install filters on the steering wheel, which would be extremely difficult due to space constraints and integration requirements, while still achieving effective noise removal.
Solution Approach 2:
The patent enables the measurement control section to perform self-service noise filtering by processing its own measurement values through digital filtering algorithms. The system independently removes interference noise from its sensor readings without requiring external physical filtering components or additional installation steps.
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 approach enhances detection accuracy by suppressing noise components from both 50 Hz and 60 Hz frequency interference, ensuring reliable touch detection regardless of the power source frequency.
Implementation Method 1
a sensor electrode provided to the steering body and configured to have an electrostatic capacitance changed by contact or close proximity of the operator to the steering body
Implementation Method 2
set an interval between adjacent averaging segments for calculating the segment average to an interval such that one segment average value is suppressed by another segment average value for 50 Hz and 60 Hz frequency components
Data Source
AI summary
A touch detection device that includes: a steering body; a sensor electrode provided at the steering body and having an electrostatic capacitance; and a measurement control section configured to: measure the electrostatic capacitance of the sensor electrode over a measurement cycle according to a measurement frequency and to output a detection value according to values measured by setting the measurement frequency to 50 Hz or 60 Hz for removal target frequencies of 50 Hz and 60 Hz, set the measurement cycle and a period for calculating a segment average of the measurement values based on the measurement frequency, and set an interval between adjacent averaging segments for calculating the segment average such that one segment average value is suppressed by another segment average value for 50 Hz and 60 Hz frequency components, and output an averaged measurement value for the two averaging segments as the detection value.