Capacitive Secondary Electrodes for Steering Wheel Sensing Coverage
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Solution Overview
Problem
Current vehicle sensor systems face challenges in achieving effective sensor placement in tight-fitting components and limited sensing area due to interference from metal materials, and existing technologies struggle to increase sensor surface density without compromising heating functionality in steering wheels with complex shapes.
Innovation Solution
The implementation of a proximate sensor system that operates electrically floating, without a direct physical connection to the controller, using a secondary electrode within the electric field generated by a primary electrode, allowing for increased sensing area and density while maintaining existing sensor layouts and connections, and accommodating complex shapes like wood or carbon fiber coverings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If sensor mat is placed close to metal steering wheel frame, then sensing capability is improved, but interference from metal frame increases
Solution Approach 1:
A shield mat with conductive loops is introduced as an intermediary component between the sensor mat and the metal steering wheel frame. The shield mat acts as a mediator that blocks electromagnetic interference from the metal frame while allowing the sensor mat to maintain its sensing capability. The conductive loops in the shield mat create a Faraday cage effect that prevents interference from reaching the sensor mat.
2Area of stationary object
If sensor surface density is increased by stitching more wires, then sensing area is improved, but risk of damaging neighboring wires increases
Solution Approach 1:
The invention creates a virtual copy of the sensor functionality by using the shield mat's conductive loops as secondary sensing elements. Instead of physically increasing wire density, the system copies the sensing capability through electromagnetic coupling between the primary sensor mat and the secondary shield mat, allowing increased effective sensing area without adding more physical wires.
Solution Approach 2:
The invention transitions from a two-dimensional wire stitching approach to a three-dimensional electromagnetic field approach. By utilizing the spatial separation between the sensor mat and shield mat, the system creates additional sensing dimensions through electric field coupling, effectively increasing sensing area without increasing planar wire density.
3Reliability
If shield mat is added to block interference, then sensing reliability is improved, but device complexity increases
Solution Approach 1:
The shield mat is designed to serve multiple functions simultaneously: it blocks electromagnetic interference from the metal steering wheel frame, provides secondary sensing capability through its conductive loops, and can be integrated with existing heating elements. This multi-functionality reduces the need for separate components, thereby limiting the increase in system complexity.
Solution Approach 2:
The invention merges the shielding function with the sensing function by using the same conductive loops in the shield mat for both interference blocking and occupancy detection. This consolidation eliminates the need for separate shield mats and sensor mats, reducing overall system complexity while maintaining both shielding and sensing capabilities.
4Adaptability or versatility
If sensor mat is installed in tight-fitting areas, then adaptability is improved, but wiring and connections become difficult
Solution Approach 1:
The secondary sensing capability through the shield mat creates a virtual extension of the sensor mat, allowing sensing in areas where physical wiring would be difficult. The electromagnetic coupling enables the shield mat to function as a wireless sensor, bypassing the need for complex wiring in tight-fitting areas.
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 solution enhances sensing capabilities in difficult-to-reach areas and on complex vehicle components, providing improved hand and occupant detection without the need for additional electrical connections, thus increasing the effective sensor surface area and charge density.
Implementation Method 1
a first electrode with a controller electrically coupled to the first electrode. The controller applies a voltage to the first electrode to generate an electric field around the first electrode
Implementation Method 2
The electrical field generated by the first electrode induces a corresponding charge on the second electrode
Implementation Method 3
proximity of a conductive material on or near the first or second electrode alters the electrical signal received back by the controller from the first electrode
Data Source
AI summary
A sensor system includes a first electrode serving as a primary electrode with a controller electrically and physically coupled to the first electrode. Computer executable instructions execute software commands on the controller causing the controller to apply a voltage to the first electrode to generate an electric field around the first electrode. A second electrode has at least a portion of the second electrode being disposed within the electrical field generated by the first electrode, and the second electrode operates while being physically decoupled from the controller. The electrical field generated by the first electrode induces a corresponding charge on the second electrode, and proximity of a conductive material on or near the first or second electrode alters the electrical signal received back by the controller from the first electrode to allow for sensing the conductive material.