Eric Bideaux

Vehicle trajectory optimization for application in ECO-driving

To reduce fuel consumption in the transportation sector research focuses mainly on the development of more efficient drive train technologies and alternative drive train designs. Another and immidiately applicable way found to reduce fuel consumption in road vehicles is to change vehicle operation such that system efficiency is maximized. The concept of Eco-driving refers to the change of driver behavior in a fuel saving way or more generally in an energy saving way. In this paper system efficiency of a vehicle is optimized using a dynamic programming optimization approach. Given a drive cycle a so called ‘eco-drive cycle’ is identified in which a vehicle performs the same distance with the same stops in equivalent time, while consuming less fuel.

Influence of the process design on the control strategy: application in electropneumatic field

Abstract This article proposes an example of electropneumatic system where the architecture of the process is modified with respect to both the specifications for position and velocity tracking and a criterion concerning the energy consumption. Experimental results are compared and analyzed using an industrial bench test. For this, a complete model of the system is presented, and two kinds of nonlinear control laws are developed, a monovariable and a multivariable based on the flatness theory.

A planar mechanical library in the AMESim simulation software. Part I: Formulation of dynamics equations

Abstract This paper presents the mathematical developments of a planar mechanical library implemented in the AMESim simulation tool. Body and joint components are the basic components of this library. Due to the library philosophy requirements, the mathematical models of the components have required a generic vector calculus based formulation of the constraint equations. This formulation uses a set of dependent generalized coordinates. The dynamics equations are obtained from the application of Jourdain’s principle combined with the Lagrange multiplier method. The body component mathematical models consist of differential equations in terms of the dependent generalized coordinates. The joint component mathematical models are based on the Baumgarte stabilization schemes applied to the geometrical, kinematic and acceleration constraint equations. The Lagrange multipliers are the implicit solution of these Baumgarte stabilization schemes. The first main contribution of this paper is the expression of geometrical constraints in terms of vectors and their exploitation in this form. The second important contribution is the adaptation of existing formulations to the AMESim philosophy.

A planar mechanical library in the AMESim simulation software. Part II: Library composition and illustrative example

Abstract This paper presents the composition of a planar mechanical library for the simulation tool AMESim. This library is composed of 5 body components: one fixed to the frame of reference and the four others corresponding to moving bodies with one to four connecting ports. These body components may be connected to any of the joint components defined in the library. There are four basic joint components for: (1) a translational joint, (2) a revolute joint, (3) a double translational joint, (4) a double translational-revolute joint. Actuated versions of the translational and revolute joints are also available. Two more joint components are also defined for coupling perpendicular motion planes. Finally four more specific components enable a linear actuator in planar motion, a spring-damper, a one dimension to two dimensions coupling and a given action to be modeled. The use of this planar mechanical library is illustrated using the example of a seven-body mechanism.

Vehicle trajectory optimization for hybrid vehicles taking into account battery state-of-charge

Hybrid vehicles are found to be one solution to reduce fuel consumption in the transportation sector. Eco-driving is a concept that is immediately applicable by drivers to improve the efficiency of their vehicle. In this work the potential of eco-driving for hybrid drive train vehicles is discussed. The operation of hybrid vehicles is strongly dependent on their energy management and therefore on battery state-of-charge. Here, the velocity trajectory will be optimized taking into account battery state-of-charge. The vehicle and its control strategy will be modeled to simulate its operation. Given constraints on distance, velocity and time the optimal velocity trajectory is computed using the dynamic programming method in a non-standard approach. The optimal operation of the vehicle is compared to standard driving with respect to fuel consumption and battery state-of-charge. The algorithm is applicable to any hybrid vehicle architecture and will be illustrated on the Toyota Prius II vehicle.

Optimal control problem in bond graph formalism

This paper presents a new way to derive an optimal control system for a specific optimisation problem, based on bond graph formalism. The procedure proposed concerns the optimal control of linear time invariant MIMO systems and can deal with both cases of the integral performance index, these correspond to dissipative energy minimization and output error minimization. An augmented bond graph model is obtained starting from the bond graph model of the system associated with the optimal control problem. This augmented bond graph, consisting of the original model representation coupled to an optimizing bond graph, supplies, by its bicausal exploitation, the set of differential-algebraic equations that analytically give the solution to the optimal control problem without the need to develop the analytical steps of Pontryagins method. The proof uses the Pontryagin Maximum Principle applied to the port-Hamiltonian formulation of the system.

Equilibrium set investigation using bicausality

The introduction of the bicausality concept in the bond graph language has allowed new analytical methodologies, for instance in the context of model inversion, mechatronic system sizing and control. The bicausality concept is here applied for solving the equilibrium state of a mechatronic system. We propose a new method, which permits us to determine the size of the equilibrium set and the algebraic system to be solved. The proposed method is applied to linear systems in a first step, and a generalization is also given for some non-linear systems. Several examples are included in order to explain the method.

Electropneumatic Cylinder Backstepping Position Controller Design With Real-Time Closed-Loop Stiffness and Damping Tuning

This paper develops a backstepping-based algorithm to control the position of an electropneumatic actuator while allowing the precise tuning of the closed-loop stiffness and damping. The proposed strategy offers an efficient method to choose the controller parameters based on a physical and linear analysis. The strict feedback form of the model, which is required in order to apply the backstepping methodology, is obtained through the use of a transformation of the systems inputs. The proposed multiple input multiple output control law as well as its parameters tuning method are validated experimentally. The experimental results are provided using an innovative test bench combining an electropneumatic cylinder and an electric linear motor. The two main contributions are: 1) the use of a new decoupling transformation to control the systems 2 DOF and 2) the description of a closed-loop damping and stiffness tuning strategy. Simultaneous position and stiffness control result in a more precise and adjustable variable stiffness actuator than the simultaneous pneumatic force-stiffness control laws generally encountered in the literature. Moreover, a specific study is conducted to clarify the interaction between pneumatic and closed-loop stiffnesses in order to combine the advantages of passive and active compliant actuators.

Trajectory optimisation for eco-driving - an experimentally verified optimisation method

Eco-driving is an immediately applicable way to reduce fuel consumption in road vehicles by changing vehicle operation such that system efficiency is maximised. In order to identify the maximum potential of eco-driving a numerical method that computes the optimal velocity profile for a specified mission is presented here. An inverse vehicle model is presented to calculate energy consumption as a function of acceleration and velocity. Given the non-linear nature of the problem and the varying constraints the dynamic programming method was chosen to solve the optimisation problem. An iterative approach, combining dynamic programming with advanced root finding methods is proposed to reduce computational time. Using hardware-in-the-loop settings the theoretically optimal velocity profiles were tested on an engine test bench. With this the potential gains of eco-driving were verified and important factors for eco-driving were identified.

Optimal sizing of an energy storage system for a hybrid vehicle applied to an off-road application

This paper aims at comparing three different configurations of energy storage systems (ESS) for a fuel cell hybrid vehicle. This study is applied on an off-road vehicle, a new concept of hybrid electric mini-excavator. The power supply system (PSS) is composed of a predefined fuel cell system and one or two energy storage systems. In this paper, the sizing and the configuration of energy storage components is explored and cost considerations are taken into account for optimal design.