Hubert Bechart

Observer-based optimal control of dry clutch engagement

Optimal control of the engagement of a dry clutch is examined paying particular attention to the drivers comfort. Due to the strong constraints and large errors of the torque control for internal combustion engines, only the normal force on the clutch disks is considered as controlled input. The resulting analytically derived controller is used in an observer- based trajectory tracking system whose performances have been tested on a highly realistic nonlinear model yielding very good results.

Improved Optimal control of dry clutch engagement

Abstract Optimal control of the engagement of a dry clutch is examined paying particular attention to the drivers comfort. Due to the strong constraints and large errors of the torque control for internal combustion engines, only the normal force on the clutch disks is considered as controlled input. The resulting analytically derived controller is tested on a highly realistic nonlinear model proving very good performance.

Dry clutch control for automotive applications

Mechanical System and Comfort Requirements.- Powertrain.- Clutch Comfort.- Dry Clutch Engagement Control.- Synchronization Assistance.- Optimal Standing-start.- Clutch Friction and Torque Observer.- Experimental Results and Control Evaluation.- Open Problems and Conclusions.

Fun-to-Drive by Feedback**

This paper is devoted to new challenging control problems arising in the automotive industry as a consequence of the customer-driven performance specifications adopted by car builders which have dramatically increased the number of new proposed automated features, where feedback interacts with the driver. In this paper, the notion of “Fun-to-Drive by Feedback” relates, to the ability to design a control scheme resulting in good ride comfort behavior as well as acceptable safe operation. The paper shows how control techniques can be used to solve some of these problems, and discusses how these subjective notions can be formalized thanks to concepts such as passivity and model matching control. The paper presents a series of examples concerning systems that provide assisted automated devices (i.e., electrical power steering and assisted clutch synchronization), as well as systems with fully automated features (i.e., steer-by-wire system and stop-and-go), in which these aspects are assessed.

Stability analysis via passivity of the lateral actuator dynamics of a heavy vehicle

The paper presents a model and a control law for the steering actuator used in heavy duty vehicles. A stability analysis has been conducted using passivity properties of the hydraulic system. These results can be used in applications where new automatic vehicle features (i.e. lateral control) are to be designed.

Lateral Control of Heavy-Duty Vehicles in a Convoy

Abstract This paper presents a kinematic model and a control law design for lateral control of heavy-duty vehicles in a convoy. These results are pertaining to applications where new automatic vehicle feature are to be designed. Control design is based on spatial linearization of the velocity relationships between two vehicle of the platoon. We also present some results obtained from a complete benchmark simulations.

H∞ State Feedback Control for Switched Linear Systems: Application to an Engine Air Path System

Abstract This paper presents the results of an engine air-path H ∞ state feedback switched linear controller. The main advantage of this approach is that controller gains are calculated offline, with the robust specifications allowing fast calculation and is cost-effective in calculation and resources. The air-path system dynamics are governed by the Saint-Venant equations, difficult to handle in control synthesis due to its nonlinear properties (states - control inputs coupling, nonlinear functions). To employ advanced control techniques, a switched linear state space representation is proposed. The model is simplified considering that slow dynamics are quite constant. The proposed approach provides a robust state feedback control toward perturbations (model error, unmodeled dynamics…) by considering these disturbances as unknown inputs.

Lurch avoidance strategy and its implementation in AMT vehicles

Conventionally the control of dry clutchs engagement during a standing start in AMT vehicles is assured by look-up tables whose values are carefully chosen to produce a smooth synchronisation at the expense of a long slipping time. This article proposes, instead, a two phase approach: a first open-loop lookup table phase aiming to reduce the slipping time and a second observer-based optimal control phase assuring the engagement comfort. Particular attention has been given to the details of the on-line implementation on a Clio AMT prototype. Experimental results show both a close match between the predicted and the actual trajectories and a high level of comfort.