Control of interconnected mechanical systems

In this paper control systems design approach, based on siding mode methods, that allows maintain some functional relation – like bilateral or multilateral systems, establishment of virtual relation among mobile robots or control of haptic systems - is presented. It is shown that all basic motion control problems - trajectory tracking, force control, hybrid position/force control scheme and the impedance control for the interacting systems- can be treated in the same way while avoiding the structural change of the controller and guarantying stable behavior of the system In order to show applicability of the proposed techniques simulation and experimental results for high precision systems in microsystems assembly tasks are presented.

Control systems with network delay

In this paper motion control systems with delay in measurement and control channels are discussed and a new structure of the observer-predictor is proposed. The feature of the proposed system is enforcement of the convergence in both the estimation and the prediction of the plant output in the presence of the variable, unknown delay in both measurement and in the control channels. The estimation is based on the available data – undelayed control input, the delayed measurement of position or velocity and the nominal parameters of the plant and it does not require apriori knowledge of the delay. The stability and convergence is proven and selection of observer and the controller parameters is discussed. Experimental results are shown to illustrate the theoretical prediction

Sliding Modes in Motion Control Systems

In this paper we discuss the realization of motion control systems in the sliding mode control (SMC) frame- work. Any motion control system design should take into account the unconstrained motion (generally perceived as a trajectory tracking) and motion of the system in contact with unknown environment (perceived as force con- trol and/or compliance control.) In the SMC framework control is selected to enforce certain preselected depend- ence among system coordinates, what is interpreted as forcing the system state to stay in selected manifold in state space. ln this paper it has been shown that such a formulation allows a unified treatment of the both un- constrained and constrained motion control and, due to the Lyapunov based design, it guaranty the stability of the motion. Moreover control design in this framework allows extension of the solution to control design in in- terconnected dynamical systems (like mobile robots or bilateral systems)

Sliding modes in sampled-data systems

The sliding mode application in discrete-time systems can result in unwanted oscillations of the controlled variable (so called chattering). To avoid above-mentioned oscillations a new approach in the design of sliding mode control is proposed in this paper. In the proposed approach the calculation of the equivalent control is not necessary while the influence of the system uncertainty and chattering are reduced. The proposed method is applicable to linear as well as nonlinear systems. It allows the design of the control without transformation of the system description to the discrete-time form (z-domain). Upper bound of the sapling time is determined from the switching function changes during the sampling period. The systems with state observers are analyzed. Experimental and simulation results are presented to clarify the design procedure and the features of the proposed algorithm

Motion control systems with network delay

In this paper motion control systems with delay in measurement and control channels are discussed and a new structure of the observer-predictor is proposed. The feature of the proposed system is enforcement of the convergence in both the estimation and prediction of the plant output in the presence of the variable, unknown delay in both measurement and in control channels. The estimation is based on the available data - undelayed control input, the delayed measurement of position or velocity and the nominal parameters of the plant - and does not require apriori knowledge of the delay. The stability and convergence is proven and selection of observer and the controller parameters are discussed. Experimental results are shown to illustrate the theoretical predictions