Set-theoretic detection of data corruption attacks on cyber physical power systems

This paper addresses a set-theoretic method for the detection of data corruption cyber-attacks on the load frequency control loop of a networked power system. The system consists of several interconnected control areas forming a power grid. Based on the overall discrete-time network dynamics, a convex and compact polyhedral robust invariant set is extracted and is used as a set-induced anomaly detector. If the state vector exits the invariant set,then an alarm will be activated, and the potential threat is considered disclosed. The attack scenario used to assess the efficiency of the proposed anomaly detector concerns corrupted frequency sensor measurements transmitted to the automatic generation control unit of a compromised control area. Simulation studies highlight the ability of a set-theoretic approach to disclose persistent and intermittent attack patterns even when they occur at the same time with changes in the power load demand.

Distributed control of mobile robots in an environment with static obstacles

This study addresses the problem of deploying a group of mobile robots over a nonconvex region with obstacles.Assuming that the robots are equipped with omnidirectional range sensors of common radius,disjoint subsets of the sensed area are assigned to the robots.These proximity-based subsets are calculated using the visibility notion,where the cell of each robot is treated as an opaque obstacle for the other robots.Based on that,optimal spatially distributed coordination algorithms are derived for the area coverage problem and for the homing problem,where the swarm needs to move to specific locations.Experimental studies demonstrate the results.

Mobile robot position control in environment with static obstacles

This study addresses the problem of efficiently navigating a differential drive mobile robot to a target pose in a region with obstacles,without explicitly generating a trajectory.The robot is assumed to be equipped with an omnidirectional range sensor,while the region may or may not be a priori known.Given the known obstacles in each iteration of the controller,the shortest path connecting the robot and the target point provides a raw desired movement direction.Considering the unobstructed area in that direction,the size of the robot and the obstacle contours in its visibility range,the reference direction is determined.Finally,respecting the velocity and acceleration constraints of the robot,the angular velocity is properly selected to rotate the robot towards the reference direction,while the linear velocity is chosen to efficiently minimise the distance to the final target,as well as to avoid collisions.After the robot has reached the target,the controller switches to orientation mode in order to fix the orientation.Experimental studies demonstrate the effectiveness of the algorithm.