In the last few decades, an increasing number of people are beginning to realize that bilateral teleoperation plays an important role in the extension of human manipulation in fields such as space, underwater exploration, medical surgery, and hazardous environments. There is also enormous and untapped potential in applying bilateral teleoperation in mobile teaching especially networked scenarios. Nowadays, education not only focuses on the passing on of knowledge but also the interaction between teacher and student. Meanwhile, increasing numbers of people are beneficial from mobile/distance education. While due to the limitations of practicing, students are limited to art subjects. Thus, with the better than better smartphones emerging, bilateral teleoperation-based mobile teaching will become a revelation to the existing education structure.
When it comes to the teleoperation system, the greatest consideration is the time delay over the transmission which influences the performance of the system. With the development of the Internet, in recent years, an increasing number of teleoperation applications are applied over this global network. There is no denying the fact that dealing with the time delay issue on the Internet has been considered as the primary challenge as it can deteriorate system performance and even destabilize it. Many studies in the literature address the problem of the transmission delay of teleoperation across the Internet. Those among them that consider the controller design and experimental simulations are mostly focused on two kinds of time delays: constant time delay and time-varying delay. As time-varying and asymmetric delays often occur in network-based bilateral teleoperation systems, designing an appropriate control system to maintain their stability has proved to be critical.
This chapter focuses on the control of bilateral teleoperation systems across the Internet which can be potentially applied in numerical mobile teaching applications. We design a controller that takes the time-varying and asymmetric delays into account. Its key features include adaptability to time-varying asymmetric delays and stability with good transparency performance. We use new controller synthesis methods to develop the system by defining appropriate Lyapunov–Krasovskii functional. This method is developed by applying tighter bounding technology in a cross terms and weighting matrix approach. Furthermore, the controller synthesis conditions are expressed as matrix inequalities, which are solvable by existing methods. We then apply the designed controller to a linear system model with increasing forward and backward delays. Finally, an experimental validation of the developed theoretical methods is used to demonstrate the effectiveness of the proposed method, and the results show that the proposed criteria improve the force tracking with less response time and less overshoot as well as with an acceptable position error.