Emergency Stop Pressure Sensor with Asymmetric Rubber Layer
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Solution Overview
Problem
Existing emergency stop pressure sensors for robots have low pressure-detection sensitivity, leading to delayed detection of contact and increased damage during collisions, especially when using compressible fluids like air.
Innovation Solution
An emergency stop pressure sensor with a pair of electrodes and an intermediate layer made of rubber or rubber composition, which generates power upon deformation, enhancing pressure detection sensitivity by differentiating deformation and hardness between sides, allowing for immediate contact sensing and rapid response.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a hollow body with compressible fluid (air) is used for pressure sensing, then the sensor structure is simple and easy to manufacture, but the pressure detection sensitivity is low
Solution Approach 1:
The patent changes the physical state of the sensing medium from compressible gas to incompressible liquid, fundamentally altering the pressure transmission characteristics. This parameter change eliminates the compliance issue that reduces detection sensitivity while maintaining the simplicity of the hollow body structure.
Solution Approach 2:
The patent transitions from a pneumatic system (using air) to a hydraulic system (using liquid). The incompressible liquid provides immediate pressure transmission when the hollow body is deformed, enabling high-sensitivity detection while preserving the simple hollow body design.
2Duration of action of moving object
If there is a delay in pressure detection, then the sensor response time is sufficient for normal operation, but damage increases during collision emergencies
Solution Approach 1:
The patent eliminates the time delay inherent in compressible fluid systems by using an incompressible liquid that transmits pressure instantly. This allows the system to rush through the detection and response process, stopping the robot immediately upon contact to prevent damage.
3Measurement precision
If the intermediate layer is made soft for comfort, then contact detection is more sensitive, but the sensor becomes less durable
Solution Approach 1:
The patent uses a composite structure combining rubber (providing softness and deformability for sensitive detection) with liquid (providing immediate pressure transmission). This composite approach achieves both high sensitivity and improved durability compared to using soft materials alone.
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
The sensor significantly improves pressure detection sensitivity, enabling immediate contact sensing and rapid shutdown of the moving robot, reducing damage from collisions.
Implementation Method 1
an intermediate layer which is made of rubber or a rubber composition and configured to generate power when deformed by contact
Data Source
AI summary
Emergency stop pressure sensors 17 are installed on both side surfaces of a movable link 11 of a robot arm 14 of an assembly robot. When a worker S unintentionally walks in a swing range Ra of the robot arm 14 and contacts the emergency stop pressure sensor 17, a detection signal is transmitted to a control unit 19, and the control unit 19 shuts power transmission to a driving source swinging the robot arm. The emergency stop pressure sensor 17 has a first electrode and a second electrode constituting a pair of electrodes and an intermediate layer formed of rubber or a rubber composition, which is disposed between the pair of electrodes, the intermediate layer generating power upon deformation caused by contact with a contacted body (the worker). A side of the intermediate layer in a laminate direction undergoes surface modification treatment and/or inactivation treatment. With this treatment, the one side and the other side of the intermediate layer have different degrees of deformation to the same deformation adding force.