relation: http://eprints.imtlucca.it/523/
title: Hybrid model predictive control application towards optimal semi-active suspension
creator: Giorgetti, Nicolò
creator: Bemporad, Alberto
creator: Tseng, H. E.
creator: Hrovat, Davor
subject: QA75 Electronic computers. Computer science
subject: TL Motor vehicles. Aeronautics. Astronautics
description: The optimal control problem of a quartercar semi-active suspension has been studied in the past.  Considering that a quarter-car semi-active suspension can  either be modeled as a linear system with state dependent  constraint on control (of actuator force) input, or a bilinear system with a control (of variable damping coefficient) saturation, the seemingly simple problem poses several interesting questions and challenges. Does the optimal control law derived from the corresponding un-constrained system, i.e. “clipped-optimal”, remain optimal for the constrained case? If the optimal control law of the constrained system does deviate from its un-constrained counter-part, how different are they? What is the structure of the optimal control law? In this paper, we attempt to answer some of the above questions by utilizing the recent development in model predictive control (MPC) of hybrid dynamical systems. The constrained quarter-car semi-active suspension is modeled as a switching affine system, where the switching is determined  by the activation of passivity constraints, force saturation, and maximum power dissipation limits. Theoretically, over an infinite prediction horizon the MPC controller corresponds to the exact optimal controller. The performance of different finite-horizon hybrid MPC controllers is tested in simulation using mixed-integer quadratic programming.  Then, for short-horizon MPC controllers, we derive the  explicit optimal control law and show that the optimal  control is piecewise affine in state. In particular, we show  that for horizon equal to one the explicit MPC control law  corresponds to clipped LQR. We will compare the derived  optimal control law to various semi-active control laws in  the literature including the well-known “clipped-optimal”.  We will evaluate their corresponding performances for both  a deterministic shock input case and a stochastic random  disturbances case through simulations.
publisher: IEEE
date: 2005-06
type: Book Section
type: PeerReviewed
identifier:   Giorgetti, Nicolò and Bemporad, Alberto and Tseng, H. E. and Hrovat, Davor  Hybrid model predictive control application towards optimal semi-active suspension.   In:  Symposium on Industrial Electronics.   IEEE, 20th - 23th June 2005, pp. 391-398.  ISBN 0-7803-8738-4       (2005)  
relation: http://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=1528942&isnumber=32652
relation: 10.1109/ISIE.2005.1528942