PORTABLE FORCE FEEDBACK DEVICE BASED ON MINIATURE ROLLED DIELECTRIC ELASTOMER ACTUATORS Rui Zhang 1 , Patrick Lochmatter 1 , Gabor Kovacs 1 , Andreas Kunz 2 and François Conti 3 1 Laboratory for Mechanical Systems Engineering, Swiss Federal Laboratories for Materials Testing and Research (EMPA), Duebendorf, Switzerland 2 Institute of Machine Tools and Manufacturing, Swiss Federal Institute of Technology (ETH), Zurich, Switzerland 3 Department of Computer Science, Artificial Intelligence Laboratory, Stanford University, Stanford, CA, USA Abstract In this chapter, we present the application of the miniature rolled dielectric elastomer (DE) actuators to a portable, ‘hand-held’ force feedback device (FFD). The miniature rolled DE actuators (diameter 12 mm, length 45 mm and weight 8 g) were fabricated based on a machine-aided manufacturing process. The actuators were characterized by isometric tests with driving voltages ranging from 0 to 3.5 kV and displacement levels between 0 and 8 mm. The results showed a quasi-linear force–displacement behaviour. Furthermore, a quadratic decrease in axial force with increasing voltage was observed, which agreed with the theoretical prediction. To ensure electrical safety to human users of the FFD driven by the miniature rolled DE actuators, two failure cases were studied based on a device-user configuration modelled in Simulink ® . Various protective measures were derived and implemented in the design of the actuators and the force feedback system. Two demonstration devices were made to practically demonstrate func- tions of the miniature rolled DE actuators in force feedback applications. Future work will address the issues such as reproducibility and electromechanical durability of the rolled DE actuators, as well as the implementation of the proposed ‘hand-held’ FFD in a force feedback control system. Keywords: Electrical safety, electroactive polymers, force feedback, rolled dielectric elastomer actuators. 20.1 INTRODUCTION Virtual reality (VR) can be traced back to about 50 years ago when Morton Heilig, a cinematographer, began designing the first multi-sensory virtual experiences. In order for spectators to be fully immersed in a film scene, he developed the ‘Sensorama Simulator’ which added to the projected film, sounds, vibrations, wind and even odours [1]. Nowadays, after a remarkable and complex history [2], VR has lead to a wide range of multi-sensory applications for entertainment and professional purposes [3–6]. While VR has strongly benefited from the important progresses in computer technology, there still remain limitations with the current techniques for including the stimulation of the sense of touch. Unlike graphical displays, which can render large photographic images at very high resolution, tactile displays can only generate limited forces within small punctual areas. With the appearance of new med- ical robotic tools to perform minimal invasive procedures in a more precise way in recent years, how- ever, there has been an increasing demand for more robust and efficient force feedback devices (FFDs) which allow users to intuitively grasp, feel and manipulate virtual or real objects [7]. In respect of their location, current FFDs can generally be classified into the categories of ground- based and body-based devices. Ground-based devices are fixed to the environment such as a desk, a Chapter 20