Development of polyimide flexible tactile sensor skin

Abstract

We present the development of a polyimide-based two-dimensional tactile sensing array realized using a novel inverted fabrication technique. Thermal silicon oxide or Pyrex R substrates are treated such that their surfaces are OH group terminated, allowing good adhesion between such substrates and a spun-on polyimide film during processing through what are suspected to be hydrogen bonds that can be selectively broken when release is desired. The release of the continuous polyimide film is rapidly accomplished by breaking these bonds. This process results in robust, low-cost and continuous polymer-film devices. The developed sensor skin contains an array of membrane-based tactile sensors (taxels). Micromachined thin-film metal strain gauges are positioned on the edges of polyimide membranes. The change in resistance from each strain gauge resulting from normal forces applied to tactile bumps on the top of the membranes is used to image force distribution. Response of an individual taxel is characterized. The effective gauge factor of the taxels is found to be approximately 1.3. Sensor array output is experimentally obtained. The demonstrated devices are robust enough for direct contact with humans, everyday objects and contaminants without undue care.

A highly sensitive multimodal capacitive tactile sensor

“…In an attempt to replicate these functions robotically, researchers have developed tactile sensors based on numerous different sensing principles, including piezoresistive rubber [3], [4], conductive ink [5], piezoelectric material [6], conductive fluid [7], [8], and change in capacitance [9], [10]. Most of these approaches are about measuring contact pressure, however the human sense of touch also includes senses of vibration, temperature and shear loading, among others.…”

Texture roughness estimation using dynamic tactile sensing

“…Most of these approaches typically use piezoresistivity [4], or capacitance [5], [6], [7] as a sensing principle, which provides only an image of the applied stress. Human hands have a complex combination of mechanoreceptors that are not only sensitive to pressure, but also to dynamic events such as the vibration that occurs at the fingertips when we touch, for example, a surface texture.…”

Acquisition of Contact Force and Slippage Using a Vision-Based Tactile Sensor with a Fluid-Type Touchpad for the Dexterous Handling of Robots

“…A wirefree tactile sensor based on transmitters/receivers [7], and a sensor based on micro coils for changing impedance by contact force [8], were housed in complex structures. Although compact sensors using microelectromechanical system (MEMS) can be manufactured, the surfaces of these sensors are minimally deformable [9][10][11][12] and cannot satisfy the first requirement as described above.…”