This paper develops an approach for driver-aware vehicle control based on stochastic model predictive control with learning (SMPCL). The framework combines the on-board learning of a Markov chain that represents the driver behavior, a scenario-based approach for stochastic optimization, and quadratic programming. By using quadratic programming, SMPCL can handle, in general, larger state dimension models than stochastic dynamic programming, and can reconfigure in real-time for accommodating changes in driver behavior. The SMPCL approach is demonstrated in the energy management of a series hybrid electrical vehicle, aimed at improving fuel efficiency while enforcing constraints on battery state of charge and power. The SMPCL controller allocates the power from the battery and the engine to meet the driver power request. A Markov chain that models the power request dynamics is learned in real-time to improve the prediction capabilities of model predictive control (MPC). Because of exploiting the learned pattern of the driver behavior, the proposed approach outperforms conventional model predictive control and shows performance close to MPC with full knowledge of future driver power request in standard and real-world driving cycles.

Stochastic MPC With Learning for Driver-Predictive Vehicle Control and its Application to HEV Energy Management

SUMMARY Based mainly on English language literature, information relating to the design of automobile suspension systems for ride comfort and control of wheel load variations for frequencies below body structure resonances is reviewed. The information is interpreted in the context of vehicles which travel through a wide speed range on roads of markedly differing quality, which do so carrying different loads and which are required to possess good handling qualities. Sections are devoted to describing road surfaces, modelling vehicles and setting up performance criteria, and to passive, active, semi-active and slow-active system types. Methods for deriving active system control laws are outlined. Strengths and weaknesses of the various systems are identified and their relative performance capabilities and equipment requirements are discussed. Attention is given to adaptation of the suspension or control system parameters to changing conditions. Remaining research needs are considered.

Road Vehicle Suspension System Design - a review

This survey paper aims to provide some insight into the design of suspension control system within the context of existing literature and share observations on current hardware implementation of active and semi-active suspension systems. It reviews the performance envelop of active, semi-active, and passive suspensions with a focus on linear quadratic-based optimisation including a specific example. The paper further discusses various design aspects including other design techniques, the decoupling of load and road disturbances, the decoupling of pitch and heave modes, the use of an inerter as an additional design element, and the application of preview. Various production and near production suspension systems were examined and described according to the features they offer, including self-levelling, variable damping, variable geometry, and anti-roll damping and stiffness. The lessons learned from these analytical insights and related hardware implementations are valuable and can be applied towards future active or semi-active suspension design.

State of the art survey: active and semi-active suspension control

http://hub.hku.hk/bitstream/10722/200659/1/Content.pdf

Passive vehicle suspensions employing inerters with multiple performance requirements

Based on the well-known quarter car representation of the automobile suspension design problem, pdomnce parameters relating to passenger discomfort, working space and tyre load variability are generated for passive, active and semi-active suspension systems. Active systems of two types having different hardware implications are considered, and linear optimal control theory is used in each case to derive a good set o control law parameters. The semi-active systems studied have control laws based on the fully active systems, but are capable only of dissipating energy, so that where the corresponding active system would be acting as an energy supply, the semi-active system switches off Practically realizable switching dynamics are assumed in the calculations. Results for all the systems, for one road surface roughness and vehicle speed, are generated in a form which allows comparison between systems of diffient types which have equal suspension working space requirements. The wider implications of the result...

The Relative Performance Capabilities of Passive, Active and Semi-Active Car Suspension Systems

SUMMARY Some linear stochastic control theory relevant to the design of active suspension systems subject to integrated or filtered white noise excitation is reviewed, and application of the theory to a particular problem is considered. The problem considered is the well known quarter car problem in which a control law which minimises a performance function representing passenger discomfort, suspension working space, and tyre load fluctuations is required. With full state feedback, the requirement for a formulation of the problem which leads to the system under consideration being observable and controllable is referred to, and it is shown how a well known coordinate transformation enables this requirement to be satisfied. With limited state (or output) feedback, problem formulations which will avoid potential numerical problems in deriving the optimal control are described. Example solutions are included in order to illustrate the methods.

The Application of Linear Optimal Control Theory to the Design of Active Automotive Suspensions

SUMMARY Passenger discomfort, suspension working space and dynamic tyre loading parameters are calculated for different combinations of spring stiffness and damping coefficient representing the suspension system in a quarter car model subject to realistic random disturbance inputs from roads of widely differing quality. Sprung and unsprung masses and the tyre vertical stiffness and damping coefficient employed derive from a current production car. Designs which are best for the specific conditions represented are identified and their performance properties in other (off-design) conditions are considered, and conventional design is explained as the inevitable consequence of the need to compromise if fixed suspension parameters are used. Performance improvements possible if variable parameters can be employed are evaluated as a function of the ranges of variability provided, and a stratagem for controlling parameters is proposed.

S. A. Hassan

Papers

The Application of Linear Optimal Control Theory to the Design of Active Automotive Suspensions

An Evaluation of Passive Automotive Suspension Systems with Variable Stiffness and Damping Parameters