Year

2016

Degree Name

Doctor of Philosophy

Department

School of Electrical, Computer and Telecommunications Engineering

Abstract

Teleoperation provides telepresence by allowing a user to remotely control a slave robot through a master device by sensing or feeling the impact of the remote environment. Because of this transference, teleoperation has been utilized in many real world applications. For instance, the ability to send a remote controlled robotic vehicle into a hazardous environment can be a great asset in many industrial applications. As well, Earth to space operations and deep sea exploration are other areas which gain significant and imperative capability by employing teleoperation. These systems offer great potential, but connecting master/slave stations in a coherent way is a challenging task. While the master station is controlled by the human operator, the slave manipulator often needs to interact with an unknown and dynamic environment from a distance. The nature of this remote interaction significantly influences the overall system performance, and poses significant challenges in terms of sensing, planning, and control. In particular, it is critical to design control algorithms that account for the dynamics of the robot and environment, and the time delay in the communication channel.

The work in this thesis is aimed to address these issues and focus on the development of an innovative adaptive observer based bilateral teleoperation algorithm for n-degrees-of-freedom (n-DOF) nonlinear manipulators interconnected with time delays. Central to the algorithm is the design of a new extended active observer for estimating the external forces acting on the manipulators while suppressing various disturbances arising from the manipulators and surrounding environments, such as measurement noise, robot model parameter variation and various friction issues. The use of this observer removes the need for both velocity and force sensors, leading to a lower cost hardware setup that also provides the benefits of a force-position architecture in terms of accurate force tracking. Stability of the observer has been verified, and it demonstrates high performance in experimental verification. Building on this new observer, new control algorithms have been developed for haptic teleoperation for both delay and delay-free situations. These teleoperation approaches have been verified through simulations and experiments on practical teleoperation systems. The results show the effectiveness of the novel teleoperation methods.

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