Design, Modeling, and Fabrication of a Magnetized Membrane-Based Tactile Sensor for Contact Force Measurement in a Robotic Hand

Abstract

Tactile sensing is a key area of research to enhance robotic hands to achieve human like manipulation skills. One of the fundamental pieces of information obtainable from tactile sensors is three dimensional contact force vector. With the knowledge of multiple three dimensional contact force vectors, grasp planners are able to account for slippage and close the loop of control strategies used in manipulation.

This thesis focuses on the design of a tactile sensor based on magnetometers and magnetized membranes soft materials with embedded magnetic particles. We investigate how the magnetized membrane can be tailored to design a tactile sensor capable of achieving model based decoupled 3D force sensing, ensuring ease of manufacturing, ease of calibration, miniaturization, modular design of arrays and cost effectiveness.

To address this, we adopt a model based approach to first understand and predict the sensor's readouts. By imposing a sinusoidal radial magnetization over the membrane we are able to anticipate the sensor's performance characteristics and focus on achieving three dimensional force sensing with independent axis calibration.

We present a design methodology for a new family of sensors featuring magnetometer, a silicone substrate and a magnetized membrane. Additionally we prototype and characterize one sensor to validate this framework. Our contributions to the field tactile sensors include the successful demonstration of a model based 3D force sensing mechanism. Experimental tests conducted with the sensor prototype confirm the effectiveness of force decoupling, validate the 3D force sensing model, and demonstrate the ease of calibration.