Two-stage neural sliding-mode control of magnetic levitation in minimal invasive surgery

A levitation platform can be inserted into a patient's abdominal cavity to perform diagnosis or a surgery procedure with a significantly reduced level of incision and an enhanced field of vision and operation. This paper proposes a new controller for the magnetic levitation, which connects the neural control (NC) and the sliding-mode control (SMC) serially, while the other neural sliding-mode controllers (NSMC) combine NC and SMC parallel. We call the new NSMC as two-stage neural sliding control. It has less chattering during its discrete realization and ensures finite-time convergence. Real-time experiments for a prototype of magnetic levitation in minimal invasion surgery are presented. The comparisons with other regular controllers, such as PID, NC, SMC, and normal NSMC, are made by experiment.