AUTONOMOUS ROBOTS

Robotics have quickly been matured by increasing efforts of the untired researchers [19, 28]. However, a lot of works still have to be done related to the growing applications in the future. For instance, applications in hazardous environment or applications that are almost impossible to be done by human beings such as in nuclear power plants [24, 12], mining industries [8], space robots [1], virtual reality [17], unmanned vehicle operations [22], medical applications [16], cell/micro-organism applications [13], semiconductor industries [27] and so on. The research direction concerning the above mentioned works is known as robot teleoperation. In a common setting, in a teleoperation system as shown in Fig. 1, the operator will exert a force on the master manipulator which in turn, results in a displacement or velocity that is transmitted to the slave side as the order or command. In order to sense the manipulated object, some informations have to be returned from the slave side to the operator side. These information could be distance measurement, velocity measurement, force measurement or their combination. By sending the information back to the master side, the human operator will be able to feel what happened in the environment for example tactile senses. However, it may cause instability in the system if the model is not exactly known or the delay presents in the communication channel. These problems have been the main challenges faced by researchers for many years.