Sung Joon Kim

The presence of a tactile sensor is essential to hold an object and manipulate it without damage. The tactile information helps determine whether an object is stably held. If a tactile sensor is installed at wherever the robot and the object touch, the robot could interact with more objects. In this paper, a skin type slip sensor that can be attached to the surface of a robot with various curvatures is presented. A simple mechanical sensor structure enables the cut and fit of the sensor according to the curvature. The sensor uses a non-array structure and can operate even if a part of the sensor is cut off. The slip was distinguished using a simple vibration signal received from the sensor. The signal is transformed into the time-frequency domain, and the slippage was determined using an artificial neural network. The accuracy of slip detection was compared using four artificial neural network models. In addition, the strengths and weaknesses of each neural network model were analyzed according to the data used for training. As a result, the developed sensor detected slip with an average of 95.73% accuracy at various curvatures and contact points.

Polymer film-type slip sensor is presented by using novel working principle rather than measuring micro-vibration. The sensor is comprised of bilayer with Ecoflex and NBR(acrylonitrile butadiene rubber) films divided by di-electric. When slip occur on surface, bilayer have relative displacement from each other because friction-induced vibration make a clearance between two layers. This displacement can be obtained by capacitance difference. CNT(carbon nanotube) was employed for electrode because of flexible and stretchable characteristics. Also normal and shear force can be decoupled by the working principle. To verify developed sensor, slip test apparatus was designed and experiments were conducted. © (2017) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.

Tactile sensor for detecting slip is essential to grasp an object safely in a robot hand with a complicated structure and various functions. In this paper, sensors with three patterns in different forms are designed to sense slip moment through a resistance change. The slip sensors developed in this paper have flexible and stretchable characteristics to be used on the robot hand surface. For realizing these characteristics, acrylonitrile-butadiene rubber (NBR) is used as a substrate of the sensor. Graphene material is employed bacause of suitable for flexible substrate as an electrode. An imprint process to produce a micro-unit sensor structure is newly developed. As a result, sensors can have an extremely small structure like human fingerprint. Experiments for performance of the developed sensors are conducted. In addition, a stretchable and fatigue tests are conducted to verify the performance of sensors with a flexible characteristic like the human skin.