Fault Detection and Fault-Tolerant Control when Using SMA Actuators in Soft Robotics

Abstract

Nowadays, smart materials, such as Shape Memory Alloys (SMA) are examined as actuators for flexible, adapting shapes and structures of soft robotics. However, several limitations such as long response times, the possibility of unintended actuation as well as structural fatigue are still present and obstructive for their utilization. For applying these actuators in field of robotics, this results in a reduction of reliability (e.g. position accuracy as well as repeatability) and safety of the overall system. To encounter this, the paper presents a method for automatic fault detection for SMA. Also an approach of fault-tolerant control will be discussed. The methods aims to ensure the operability of the overall system, comprising multiple SMA actuators even in case of significantly changed system parameters or failure of single actuators.