Search

This paper considers a tracking system developed for a full-actuated manipulator with flexible joints under the following assumptions: torques are control actions, and current loop dynamics are not considered; the mass-inertial characteristics of the manipulator and other parameters are not exactly known; the external matched and unmatched disturbances act on the system, and matched disturbances are not smooth; the derivatives of the reference actions are achievable but are unknown functions of time; the set of sensors is not complete. Based on the representation of the control plant model in a block form of input–output with respect to mixed variables (functions of state variables, external influences and their derivatives), we have developed a combined control law for the case where the control matrix contains additive uncertain elements. In addition, we have designed the mixed variable observers of the smallest possible dimension with piecewise linear corrective actions for two cases: (i) only the generalized coordinates of the manipulator are measured; (ii) only the angular positions and velocities of the motors are measured. It is shown that in a closed-loop system with dynamic feedback, a given tracking error stabilization accuracy is provided in the conditions of incomplete information. We presented the results of numerical simulation of these algorithms for a single-link manipulator.

In this paper, a stabilization problem of angular positions is considered for the twin rotor electromechanical system under parametric uncertainties and the presence of cross-couplings between rotors. The procedure of block synthesis of nonlinear local feedbacks and discontinuous controls is developed. This procedure allows satisfying the project restrictions on the state variables and control actions. The simulation results of the developed procedure are presented.

The paper deals with the twin rotor MIMO system, which behavior is much similar to the behavior of a real technical device – a helicopter. The tracking problem of the generalized coordinates (yaw and pitch angles) for the given trajectories is posed in the conditions of the model's parametric uncertainties and in the action of unknown external disturbances. The decomposition synthesis of the control law is performed on the basis of the block approach using non-linear S-shaped sigmoidal feedbacks. The reduced order state observer with sigmoidal corrective action is constructed to obtain the estimates of the generalized velocities when generalized coordinates are measured. It is shown that the use of sigmoidal feedback allows us to reduce the possible overshoot at the beginning of transient responses, and to provide tracking of given signals with a given accuracy invariant with respect to parametric and external disturbances without using exogenous dynamic models of external influences.

In this paper we consider the tracking problem for a given action for a linear SISO plant, which model is presented in the input-output form. The problem is posed in the presence of noisy measurements and restrictions on the state variables and control action. The information about the derivatives of the given action is absent. The block synthesis procedure with nonlinear sigmoidal functions in feedbacks is developed for the solution of this problem. Whereas the estimation of state variables and measurement filtering are performed by using Kalman-Bucy filter.

The paper deals with block design of control system of gripper position of a manipulator under conditions of uncertainty of load mass and incomplete measurements. Restrictions on the state variables of the electromechanical system in the controlt process are provided by use of S-shaped smooth sigma-functions in local feedbacks and corrective actions of the states observer.