To improve the manoeuvrability of differential drive mobile robots around a straight path on a horizontal plane, an I/O decoupling control scheme is proposed through a proportional controller that uses real time measurements of the kinetic variables of the mobile robot and measurements of the orientation of the robot, received through a wireless network providing communication delays. The present control scheme is based on the linear approximant of the robot model. The I/O decoupling design requirement is proven to be always satisfied and the controller is proven to be a common controller for various values of the robot parameters The stability and asymptotic command following of the closed loop system is studied. The resemblance of the performance of the closed loop system, using the delayed controller, to the respective response of the closed loop system for zero delay, is accomplished through a metaheuristic algorithm. The efficiency of the derived controller when applied to the nonlinear model of the mobile robot is illustrated through simulations.

The problem of controlling the position of a magnetically levitated ball is studied through a PD state feedback linear controller and the simultaneous satisfaction of a set of individual miscellaneous design requirements including stability, command following, model following and appropriately bounded input. The requirements are defined over the linear approximant of the magnetic levitation system. Also, for the solution of the problem, a metaheuristic algorithm, based on the linear approximant of the magnetic levitation system, is proposed. The performance of the proposed control scheme, for the resulting nonlinear closed loop system, is illustrated through a series of computational experiments.

The problem of active vibration absorption for ride comfort improvement is investigated upon a quarter car model. Using the linear approximant of the plant, a PID controller that minimizes the L1 norm of the impulse response mapping the disturbance to the performance output is proposed. The controller parameters are selected using a metaheuristic algorithm. The performance of the proposed scheme is illustrated through simulation.

The problem of speed control of a permanent magnet synchronous motor is investigated in the presence of time delays due to wireless signal transmission among the controller, the sensors and the actuators. In the present paper, the decoupling controller approach proposed in [1] is extended to compensate the presence of the delays and to achieve satisfactory performance despite their presence. In particular, the research focuses mainly on the stability of the time delay closed loop system.

The problem of triangular decoupling with simultaneous disturbance rejection (TDDR) is studied for general neutral multi delay systems via a realizable dynamic multi delay controller feeding back measurable disturbances and the plant measurement outputs. The necessary and sufficient conditions for the problem to have a solution are established and the general analytical expression of the realizable multi delay dynamic controllers solving the problem is derived. The results are successfully applied to control an activated sludge process with varying dissolved oxygen concentration at the influent.

The problem of block decoupling is studied for the case of general neutral multi delay systems. The system is not restricted to be square and invertible. The controller is of the general neutral dynamic type involving a dynamic feedback and dynamic precompensator. Two different cases of feedback are studied. The first is the case of measurable output feedback and second is the case of performance output feedback. The controller is restricted to be realizable. The necessary and sufficient conditions for the problem to be solvable are established. The general class of the realizable controllers solving the problem is derived. The closed loop transfer function is proven to have arbitrary characteristic polynomial thus facilitating command tracking and stability.

For the class of non square general neutral time delay systems the problem of triangular decoupling is extensively solved using a dynamic realizable controller with dynamic measurement output feedback and dynamic precompensator. The necessary and sufficient condition for the solvability of the problem is established and a general class of realizable controller matrices solving the problem is derived. The condition is proven to be the right invertibility of the open loop system. The above results are successfully applied to a small scale activated sludge process (ASP) where a two stage dynamic controller is designed. The inner loop controller is a triangular decoupling controller while the outer loop controller, is used to compensate model uncertainties and nonlinearities of the plant. The performance of the closed loop system is illustrated through simulation.

The control problem of a central heating system is studied via a PD controller feeding back the environment temperature and the performance output, i.e. the temperature of the heated room. The design goal is to compensate the influence of the environment temperature to the room temperature. To achieve this goal, a PI controller has supplementary been used. Even though, the controller is simple and easily implementable to low level control architectures, the performance the closed loop system is satisfactory. The parameters of the controller are computed using pure and mixed heuristic schemes based on the linearization of the nonlinear general neutral plant and minimizing the norm of the influence of the disturbance to the plant output.

A control design scheme is proposed for sloshing suppression during liquid transfer using robotic manipulators. The container of the liquid is transferred by an articulated manipulator. The motion of the liquid is approximated using the well-known pendulum-type model. The proposed control scheme combines a partial inverse dynamics controller with a PID controller tuned with a "metaheuristic" search algorithm. The proposed controller exploits measurements of the manipulator and the container position and velocity variables, but does not require measurements of the pendulum's position and velocity. The proposed design technique succeeds to sufficiently suppress liquid sloshing within the container, while dealing with practical problems like the lack of measurements of the liquid's motion within the tank.