József Bokor

Theoretical aspects of high-speed supercavitation vehicle control

A control system based on feedback linearization is developed for a high-speed supercavitating underwater vehicle. The supercavitation bubble surrounding the body leads to reduced drag but is also responsible for the undesired switched, nonlinear and delay dependent behavior caused by the phenomena known as planing. The theoretical contributions of the switched control design are discussed in connection with the mathematical description of the system. Special attention is made to understand and handle the complex and novel dynamics of the vehicle

Controllability of bimodal LTI systems

This paper gives a self contained treatment of the bimodal LTI problems pointing to the relevant structures of the problem. It is shown that for a certain class of bimodal systems controllability in case of closed-loop switching systems is equivalent with controllability of an open-loop switching system using nonnegative controls, i.e., to the controllability of a constrained open-loop switching system. To illustrate the main ideas, illustrative examples are also provided.

Tuning and Improvements in a Waypoint and Trajectory Tracking Algorithm

This paper deals with waypoint guidance and trajectory tracking of aircrafts. After briefly introducing a previously published and a newly developed waypoint guidance strategy (publishing real flight test results also), it makes a literature review. The goals of the work are set based on this review. Considering these goals, the fine tuning of the newly developed algorithm is done first. Then linear and circular waypoint reachability maneuvers are examined. It is pointed out that it is better to start to turn away from the waypoint if it is unreachable then turn toward it if it becomes reachable. Finally, the article extends the capabilities of the new algorithm to track given parametric spatial trajectories. This extended capability is demonstrated in a simulation example.

Controllability of bimodal LPV systems

Abstract This paper gives a self contained treatment of the controllability of bimodal LPV systems pointing to the relevant structures of the problem. The subsystems are supposed to be affine LPV systems. It is shown that for a certain class of bimodal systems controllability in case of closed-loop switching systems is equivalent with controllability of an open-loop switching system using nonnegative controls, i.e., to the controllability of a constrained open-loop switching system. The aim of the paper is to give some sufficient algebraic conditions that guarantees, in the generic case, controllability of some LPV bimodal systems.

Error analysis of attitude estimation with focal-plane processors for guidance for mobile robots

In this paper the results of the error analysis of four different feature point based attitude estimator algorithm is introduced. The algorithms was tested in simulation with realistic flight paths and camera models. With these results a best performing candidate algorithm can be chosen for a given focal-plane processor and for the given scenarios.

Performance metrics for fault detection and isolation filters

Fault detection and isolation (FDI) filters are typically synthesized for open-loop or closed-loop systems. The controller affects the FDI filter performance in the closed-loop. Performance metrics for FDI filters are proposed to assess filter performance and controller-filter interaction in the presence of uncertain dynamics in the closed-loop. The role of controllers robustness to plant uncertainty in FDI filter performance is examined.