Observer-based controller design for the minimally invasive surgery

Due to its advantages like minimal trauma and a low risk of infections, the minimally invasive surgery (MIS) has become the standard operation technique for many surgical procedures. During this type of intervention, one of the main tasks from a technical point of view is the control of the pressure in the operation area in order to give the surgeon sufficient space to perform his actions. Because no invasive measurements are available, an extended Kalman filter incorporating the peristaltic behavior of the used medical device was developed to estimate the pressure in the operation area. This contribution focuses on the observer design while a separately designed PI controller using loop shaping was employed for validation. The proposed observer-based control structure was tested with a simulator deploying the principle of physical equivalence

Investigation of advanced control for adaptive optics in free-space optical communication

Free-Space Optical (FSO) communication can play an important role in meeting the demands of future high throughput and high data rate communication applications. However, atmospheric turbulence induced effects degrade the performance of FSO communication links resulting in high volume data losses. Adaptive Optics (AO) can be used to mitigate the effects of atmospheric turbulence in FSO links. A key challenge is the fact that turbulence scenarios in FSO links are stronger and FSO links are expected to remain operational in all conditions. This requires a robust AO controller that can cope with the more extreme turbulence. In this work, the design and simulation of one such advanced controller based on Linear Quadratic Gaussian control (LQG) is presented. The operation of the controller is demonstrated with an end-to-end simulation. The simulation uses multi-layer phase screens for representing the turbulent atmosphere and angular spectrum propagation for accuracy. We present here the performance of the AO controller through an analysis of the Strehl ratio, the fiber coupling efficiency and the power scintillation index on the fiber achieved