Optimization of two-channel bilateral control based on sensitivity function through transparency analysis

Bilateral control methods seek to provide a system that allows an operator to interact with a remote environment as if the operator was actually interacting directly with said environment. To achieve this means to make the system itself transparent to the operator. For this reason only the amount of synchronization of position and forces of a master-slave pair is not enough to define the correct realization of a bilateral teleoperator, thus, it becomes necessary to analyze any bilateral method according to transparency indexes, known as operationality and reproducibility. These two indexes allow to define the amount of interference from the dynamics of the system itself that affect the feeling of transparency as well as how well the remote environment impedance is reproduced in the operated side. The current paper presents a transparency analysis of a two-channel bilateral control method based on sensitivity function, and then presents how the results of the transparency analysis can be used to redesign the parameters of the method to ensure a better transparency. The analysis presented focuses on achieving the ideal values for reproducibility and operationality and then redesigning the controllers of the method. The two-channel bilateral control method uses complementary sensitivity function Q for the definition of the control method, because of this, it is not necessary to redesign the whole system, rather, it is possible to redesign only said parameters to obtain a better transparency result.