Haptic Device Design and Teleoperation Control Algorithms for Mobile Manipulators

The increasing need of teleoperated robotic systems implies more and more often to use, as slave devices, mobile platforms (terrestrial, aerial or underwater) with integrated manipulation capabilities, provided e.g. by robotic arms with proper grasping/manipulation tools. Despite this, the research activity in teleoperation of robotic systems has mainly focused on the control of either fixed-base manipulators or mobile robots, non considering the integration of these two types of systems in a single device. Such a combined robotic devices are usually referred to as mobile manipulators: systems composed by both a robotic manipulator and a mobile platform (on which the arm is mounted) whose purpose is to enlarge the manipulator’s workspace. The combination of a mobile platform and a serial manipulator creates redundancy: a particular point in the space can be reached by moving the manipulator, by moving the mobile platform, or by a combined motion of both. A synchronized motion of both devices need then to be addressed. Although specific haptic devices explicitly oriented to the control of mobile manipulators need to be designed, there are no commercial solution yet. For this reason it is often necessary to control such as combined systems with traditional haptic devices not specifically oriented to the control of mobile manipulators. The research activity presented in this Ph.D. thesis focuses in the first place on the design of a teleoperation control scheme which allows the simultaneous control of both the manipulator and the mobile platform by means of a single haptic device characterized by fixed base and an open kinematic chain. Secondly the design of a novel cable-drive haptic devices has been faced. Investigating the use of twisted strings actuation in force rendering is the most interesting challenge of the latter activity.