Vehicle Steering Wheel Sensor System Capacitive Interference Reduction
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing sensor systems for steering wheels with capacitive sensors and heating devices face interference issues that affect sensor accuracy, particularly due to capacitive coupling with the heating device, which compromises both sensor sensitivity and heating efficiency.
Innovation Solution
The sensor system coordinates the control of the capacitive sensor device and heating device to minimize interfering capacitive coupling by switching off the heating device during detection and using active shielding elements to reduce disruptive couplings, allowing for precise hand detection without impairing heating performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a shielding element is arranged between the heating device and the sensor device to capacitively decouple them, then the sensor accuracy is improved, but the heating output efficiency is reduced
Solution Approach 1:
The patent applies dynamics by making the shielding element movable rather than fixed. The shielding element can be positioned between the heating device and sensor device during measurement phases to block capacitive coupling, and repositioned during heating phases to restore thermal efficiency. This dynamic reconfiguration allows the system to optimize for different operational modes without permanent compromise to either accuracy or heating performance.
Solution Approach 2:
The system implements periodic action by alternating the position of the shielding element between measurement and heating operations. During measurement cycles, the shielding element is positioned to maximize sensor accuracy by blocking capacitive interference. During heating cycles, the shielding element is repositioned to minimize thermal resistance and maximize heating efficiency. This periodic repositioning resolves the contradiction by time-multiplexing the two opposing requirements.
2Object-affected harmful factors
If the heating device is shielded from the outside by a shielding element, then the sensor device is protected from interference, but the heating efficiency is impaired
Solution Approach 1:
The shielding element is designed as a movable component that can dynamically change its position based on operational requirements. During measurement phases, it positions itself to provide maximum interference protection for the sensor device. During heating phases, it moves to a position that minimizes thermal resistance, thereby maintaining heating efficiency. This dynamic adaptability allows the system to satisfy both protection and efficiency requirements at different times.
Solution Approach 2:
The patent segments the shielding function from the heating function by using a separate, movable shielding element rather than a fixed integrated structure. This segmentation allows the shielding element to be independently positioned and controlled, enabling it to provide electromagnetic protection during measurement without permanently compromising the heating efficiency. The segmentation decouples the two conflicting functions, allowing each to be optimized independently at different operational phases.
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 sensor accuracy and sensitivity while maintaining efficient heating performance by reducing capacitive interference, enabling reliable hands-on/off detection without the need for additional shielding elements.
Implementation Method 1
the presence of a human hand in a detection area of the sensor structure causes a detectable change, assigned to the sensor structure, of a capacitive coupling of the sensor structure with the environment and/or a reference electrode
Implementation Method 2
The heating device has at least one electrically conductive heating structure for heating the steering wheel
Data Source
Figure 1~2
Figure 3~4
Figure 5~6b
AI summary
The invention relates to a sensor system (100, 200, 300) for a motor vehicle steering wheel (10, 20), comprising a capacitive sensor device, a heating unit and a control device, said capacitive sensor device has an electroconductive sensor structure (11) and is designed to detect the presence of a human hand in the gripping area of the steering wheel (10, 20). Said sensor system (100, 200, 300) is designed in such a way that the presence of a human hand in a detection area of the sensor structure (11) respectively provokes a modification of a capacitive coupling of the sensor structure (11) with the surroundings and/or a reference electrode with respect to the reference state, said modification being associated with the sensor structure (11) and can be detected, and the sensor device and the heating device can be controlled so as to agree with each other, such that an interfering capacitive coupling of the sensor device with the components of the sensor system (100, 200, 300) and/or with components of the steering wheel (10, 20) is reduced during the detection of the modification of the capacitive coupling of the sensor structure (11) to the surroundings and/or a reference electrode. The invention also relates to a steering wheel (10, 20) comprising said type of sensor system (100, 200, 300) and to a method for operating said type of sensor system.