OPTEC - K.U.Leuven Center of Excellence: Optimization in Engineering

"Constrained feedforward control design and some first extensions to optimal control"
Knut Graichen
Postdoc at Centre Automatique et Systèmes, Ecole des Mines de Paris(France), on indirect optimal control (joint work with Nicolas Petit)

Feedforward controls are used in many practical control applications to enhance the tracking performance while maintaining the classical feedback loop. A typical control problem thereby is the transition between stationary setpoints, e.g. position changes of mechatronic systems or load changes in process control. In this context, the first part of the talk presents a new approach of inversion-based feedforward control design, which treats the setpoint change scenario as a two-point boundary value problem (BVP) in the coordinates of the input-output normal form. Constraints on the output trajectory and its time derivatives are directly incorporated within the formulation of the BVP by means of saturation functions. The approach is illustrated for swing-up and side-stepping maneuvers of a double and triple pendulum with both numerical and experimental results.
The second part of the talk presents first results on how the saturation function concept for handling the output constraints in the feedforward design can be extended to optimal control problems with state and input constraints. Several examples are used to illustrate the ideas.

Slides