Capacitive Sensor Mode Switching for Force and Proximity Detection
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Solution Overview
Problem
The existing use of separate capacitive sensors for force and proximity applications in handling technology, such as gripping or clamping devices, requires additional components and space, increasing costs and complexity, particularly in human-robot collaboration where safety demands precise detection of both pressure and collision prevention.
Innovation Solution
A capacitive sensor system with a first switching position for detecting force by changing capacitance due to object contact and a second switching position for detecting proximity by altering capacitance through an electric field interaction with approaching objects, allowing a single sensor to function as both a pressure and proximity sensor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If two separate capacitive sensors are used (one for force measurement and one for proximity detection), then both force and proximity functions can be performed, but the device complexity and component quantity increase
Solution Approach 1:
The patent applies multi-functionality by enabling a single capacitive sensor to perform both force measurement and proximity detection through software configuration. The sensor system can be switched between different measurement modes (force sensor mode and proximity sensor mode) without requiring separate physical sensors, thereby reducing device complexity while maintaining versatility
Solution Approach 2:
The patent merges the functions of two separate sensors (force sensor and proximity sensor) into a single capacitive sensor system. By combining the electrode structure and using mode-switching logic, the system integrates multiple sensing capabilities into one unified device, reducing the number of components and simplifying the overall system architecture
2Adaptability or versatility
If two separate capacitive sensors are installed, then both force and proximity sensing capabilities are available, but the installation space required increases
Solution Approach 1:
The sensor system provides universal sensing capability that covers both force measurement and proximity detection functions within a single sensor unit, eliminating the need for separate sensor installations and thereby reducing the total installation space required
Solution Approach 2:
By merging the functional capabilities of two separate sensors into one physical sensor, the system reduces the spatial footprint required for sensor installation while maintaining both sensing capabilities through software-based mode switching
3Reliability
If two different capacitive sensors are used, then comprehensive safety monitoring is achieved, but the system costs increase
Solution Approach 1:
The patent implements a universal sensor platform that can operate in different safety-critical modes (force sensing for contact detection and proximity sensing for collision prevention). This multi-functional approach maintains comprehensive safety monitoring capability while reducing the number of components and associated costs
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 dual-functionality reduces component and space requirements, enhancing safety and operational efficiency by enabling the detection of process forces and preventing collisions with a single sensor, thus minimizing costs and complexity in handling devices.
Implementation Method 1
Capacitive sensors operate based on the change in capacitance of a single capacitor or an entire capacitor system. Capacitive sensors are based on two electrodes forming the 'plates' of an electrical capacitor, whose capacitance or change in capacitance is measured.
Implementation Method 2
In this second switching position, a first capacitor is of course still present between the first sensor electrode and the second sensor electrode. However, the first sensor electrode no longer acts as a shielding electrode; instead, a voltage can be applied such that electric field lines emerge from the first sensor electrode.
Data Source
Figure 1~2
Figure 3
AI summary
Capacitive sensor (2) comprising a first sensor electrode (4) and a second sensor electrode (6), the sensor (2) having a first switching position in which the first sensor electrode (4) and the second sensor electrode (6) form a capacitor , wherein the first sensor electrode (4) is designed as a shielding electrode, and wherein a change in capacitance of the capacitor can be detected by a force F that can be exerted on the first sensor electrode (4) by means of an object touching the first sensor electrode (4), and that the sensor (2 ) has a second switching position in which an electric field can be generated at the first sensor electrode (4) in such a way that a change in capacitance can be detected when an object (32) approaches the first sensor electrode (4).