Teleoperated robots (master-slave manipulators), as the name indicates, are meant for manipulating objects from a distance. The technical requirements of such a teleoperation system translate into accurate position tracking by the slave, and accurate reproduction of the environmental forces by the master. Maintaining the ‘transparency’ of the system requires force feedback from the slave. Since the feedback has to occur across long distances, there arises time delays and instability. Thus, stability and transparency which are the two performance objectives of a teleoperation system, are conflicting in nature. This trade-off between stability and transparency is the primary challenge while implementing teleoperation systems.

Methodologies to simultaneously achieve (rather enhance) the stability and transparency of teleoperation systems is presented in this work. Three strategies are proposed for achieving this: 1) Isotropy-based design of master and slave arms to facilitate a two-channel architecture rather than the conventional four-channel architecture 2) Design of novel, passivity-based, force and position controllers for master and slave arms 3) Design of impedance controller to ensure safe interaction of slave robots with various environments. The effect of inherent time-varying delays in the communication channels are also considered while developing the strategies for enhancing the stability and transparency.

It is shown that isotropy based design facilitates a two-channel architecture for the teleoperation system, rather than the traditional four-channel architecture. Such two-channel architecture not only simplifies the implementation, but also reduces the ill-effects of time delay. In addition to altering the architecture, novel position and force controllers for the master and slave robots are proposed to enhance the performance objectives of the system. The necessary position and force controllers are developed in this work to meet the position tracking and force tracking objectives. The proposed controllers are then analytically verified using the non-linear tool of passivity. It is demonstrated that the system becomes globally asymptotically stable after the incorporation of the proposed controllers. The uniqueness of these controllers is that they provide huge flexibility in gain tuning, which is a major challenge for non-linear systems. Any kind of position or force controllers have a limitation of being able to interact with only a certain range of environments. To overcome this, impedance controllers are developed in this work to ensure safe interaction with any kind of environment. These novel impedance controllers for the master and slave robot impose modulation of the robot dynamics so as to become compatible with the dynamics of the environment.

The outcome of the proposed work in this thesis is that teleoperation systems could be conveniently implemented using an architecture which uses only half the number of conventionally required channels. In addition, the slave robot is given the flexibility to interact with any kind of arbitrary environment, even in the presence of random delays up to 1.5 sec. in the channel.