MODEL BASED PREDICTIVE CONTROL OF UNDERACTUATED NONLINEAR MECHATRONICAL SYSTEMS

The paper deals with model predictive control of underactuated nonlinear mechatronical systems along known reference path. It generalizes the state space predictive control algorithm of linear time invariant (LTI) systems to linearized time variant (LTV) systems. An algorithm is presented, which calculates the LTV model online from the nonlinear model along the reference trajectory. The LTV is then used in the framework of the predictive control to find the optimal control in closed analytical form without using online optimum search in the moving horizon. After MATLAB-based simulation results of the algorithm, successful test experiments were performed for the predictive control of a real inverted pendulum system, both in the swinging up and upper stabilization phases

Intermittent predictive control of an inverted pendulum

Intermittent predictive pole-placement control is successfully applied to the constrained-state control of a prestabilised experimental inverted pendulum

Intermittent control models of human standing: similarities and differences

Two architectures of intermittent control are compared and contrasted in the context of the single inverted pendulum model often used for describing standing in humans. The architectures are similar insofar as they use periods of open-loop control punctuated by switching events when crossing a switching surface to keep the system state trajectories close to trajectories leading to equilibrium. The architectures differ in two significant ways. Firstly, in one case, the open-loop control trajectory is generated by a system-matched hold, and in the other case, the open-loop control signal is zero. Secondly, prediction is used in one case but not the other. The former difference is examined in this paper. The zero control alternative leads to periodic oscillations associated with limit cycles; whereas the system-matched control alternative gives trajectories (including homoclinic orbits) which contain the equilibrium point and do not have oscillatory behaviour. Despite this difference in behaviour, it is further shown that behaviour can appear similar when either the system is perturbed by additive noise or the system-matched trajectory generation is perturbed. The purpose of the research is to come to a common approach for understanding the theoretical properties of the two alternatives with the twin aims of choosing which provides the best explanation of current experimental data (which may not, by itself, distinguish beween the two alternatives) and suggesting future experiments to distinguish between the two alternatives