Capacitive Operating Element Sensing for Minimal-Stroke Vehicle Controls
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Solution Overview
Problem
Existing operating devices for vehicle components face challenges in reliably detecting the actuation of operating elements with minimal movement strokes, as they struggle to accurately measure small displacements due to high system stiffness.
Innovation Solution
An operating device with an elastically mounted control element and a capacitor having a rigid and a bendable carrier body, where the capacitor's capacitance changes significantly upon actuation, allowing for precise displacement measurement and force determination by measuring the change in capacitance as the bendable carrier body moves away from the rigid one.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of moving object
If the system stiffness is increased to reduce movement stroke, then the displacement becomes smaller, but the measurement reliability deteriorates
Solution Approach 1:
The patent changes the measurement parameter from direct displacement measurement to capacitance measurement. By measuring the capacitance change caused by the displacement of the bending beam, the system can reliably detect very small displacements even when the movement stroke is minimized, thus resolving the contradiction between small stroke and measurement reliability.
2Length of moving object
If the distance between capacitor electrodes is increased to improve measurement range, then the capacitance decreases, but the measurement precision deteriorates
Solution Approach 1:
The patent utilizes the relationship between capacitance and distance by positioning the bending beam (second electrode) such that its displacement during actuation creates a measurable capacitance change. The evaluation unit detects the capacitance change caused by the beam's movement, enabling precise measurement within a limited distance range while maintaining adequate capacitance values.
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 enables reliable detection of minimal movement strokes and accurate determination of actuation force, improving the precision of force measurement and providing tactile feedback, while maintaining a small air gap to maintain high capacitance in the rest position.
Implementation Method 1
a bending beam cut free and incorporated in a printed circuit board is deformed when it is pressed down
Implementation Method 2
the change in the capacitance of this capacitor is used to detect the actuation of the operating element and to detect the path
Implementation Method 3
capacitively determining a displacement of the operating element by measuring the change in the capacitance of a capacitor
Data Source
Figure 1~4
AI summary
The operating device for an item of electrical equipment or a system, in particular for a vehicle component, is provided with at least one elastically mounted operating element (12), a counter-element (14), relative to which the at least one operating element (12) is movable when actuated, thereby varying the distance, namely as seen in the movement direction, and at least one capacitor (38) which comprises a first carrier body (20) with a first capacitor electrode (34) and an elastically bendable second carrier body (22), designed as a bending bar, having a first end (26) and a second end (32) opposite said first end and having a second capacitor electrode (36) opposite the first capacitor electrode (34). Connected to the first and second capacitor electrode (34, 36) is an evaluation unit (42) for determining the capacitance and/or a change in the capacitance of the at least one capacitor (38) upon actuation of the at least one operating element (12).