Transportation research. part c, emerging technologies

Data-driven uncertainty quantification using the arbitrary polynomial chaos expansion

This paper considers actuator redundancy management for a class of overactuated nonlinear systems. Two tools for distributing the control effort among a redundant set of actuators are optimal control design and control allocation. In this paper, we investigate the relationship between these two design tools when the performance indexes are quadratic in the control input. We show that for a particular class of nonlinear systems, they give exactly the same design freedom in distributing the control effort among the actuators. Linear quadratic optimal control is contained as a special case. A benefit of using a separate control allocator is that actuator constraints can be considered, which is illustrated with a flight control example.

Resolving actuator redundancy: optimal control vs. control allocation

Self-driving vehicles will soon be a reality, as main automotive companies have announced that they will sell their driving automation modes in the 2020s. This technology raises relevant controversies, especially with recent deadly accidents. Nevertheless, autonomous vehicles are still popular and attractive thanks to the improvement they represent to people’s way of life (safer and quicker transit, more accessible, comfortable, convenient, efficient, and environment-friendly). This paper presents a review of motion planning techniques over the last decade with a focus on highway planning. In the context of this article, motion planning denotes path generation and decision making. Highway situations limit the problem to high speed and small curvature roads, with specific driver rules, under a constrained environment framework. Lane change, obstacle avoidance, car following, and merging are the situations addressed in this paper. After a brief introduction to the context of autonomous ground vehicles, the detailed conditions for motion planning are described. The main algorithms in motion planning, their features, and their applications to highway driving are reviewed, along with current and future challenges and open issues.

/pdf/a-review-of-motion-planning-for-highway-autonomous-driving-56ou2tzah8.pdf

A Review of Motion Planning for Highway Autonomous Driving

Understanding the driver of an automobile has been attractive to researchers from many different disciplines for more than half a century. On the basis of their acquirements, models of the (human) driver have been developed to better understand, analyse and improve the combined couple of driver and automobile. Due to distinctive demands on the models in accordance with different kinds of applications, a variety of driver models is available. An overview of driver models is given with respect to their application and different methodical modelling approaches. The emphasis is put on the interest of engineers, who generally focus on the automobile (like design and optimization of vehicle components and the overall vehicle dynamics behaviour) by applying their approved (mathematical) methods. Nonetheless, a brief look beyond is added to better complete the view on the involved task of driving and driver modelling for automobile dynamics application.

Driver models in automobile dynamics application

In this paper we derive a new dynamic friction force model for the longitudinal road/tire interaction for wheeled ground vehicles. The model is based on a dynamic friction model developed previously for contact-point friction problems, called the LuGre model. By assuming a contact patch between the tire and the ground we develop a partial differential equation for the distribution of the friction force along the patch. An ordinary differential equation (the lumped model) for the friction force is developed, based on the patch boundary conditions and the normal force distribution along the contact patch. This lumped model is derived to approximate closely the distributed friction model. Contrary to common static friction/slip maps, it is shown that this new dynamic friction model is able to capture accurately the transient behaviour of the friction force observed during transitions between braking and acceleration. A velocity-dependent, steady-state expression of the friction force versus the slip coefficient is also developed that allows easy tuning of the model parameters by comparison with steady-state experimental data. Experimental results validate the accuracy of the new tire friction model in predicting the friction force during transient vehicle motion. It is expected that this new model will be very helpful for tire friction modeling as well as for anti-lock braking (ABS) and traction control design.

/pdf/dynamic-friction-models-for-road-tire-longitudinal-49jszc6j3g.pdf

Dynamic friction models for road/tire longitudinal interaction

This paper deals with the longitudinal and lateral control of an automotive vehicle within the framework of fully automated guidance. The automotive vehicle is a complex system characterised by highly nonlinear longitudinal and lateral coupled dynamics. Consequently, automated guidance must be simultaneously performed with longitudinal and lateral control. This work presents an automated steering strategy based on nonlinear model predictive control. A nonlinear longitudinal control strategy considering powertrain dynamics is also proposed to cope with the longitudinal speed tracking problem. Finally, a simultaneous longitudinal and lateral control strategy helps to improve the combined control performance. This whole control strategy is tested through simulations showing the effectiveness of the present approach.

/pdf/combined-longitudinal-and-lateral-control-for-automated-51b1q0rv0m.pdf

Combined longitudinal and lateral control for automated vehicle guidance

https://hal.archives-ouvertes.fr/hal-00696271/document

Sensitivity study of dynamic systems using polynomial chaos

https://hal.archives-ouvertes.fr/hal-00933588/document

Driver-aid system using path-planning for lateral vehicle control ☆

An automatic process is provided for automatically determining a current speed limitation on a road being used by a motor vehicle, in which by means of a first system, making use in particular of a GPS aerial and cartographical details, a first set of information is established, in which at least one likely speed limitation is associated with a confidence index; by means of a second system, involving the use of a camera and image processing applications capable of identifying roadside speed limitation panels, a second set of information is established comprising at least one probable speed limitation, wherein the basis of the first and second sets of information, the current speed limitation is determined along the road in question.

Michel Basset

Papers

Dynamic friction models for road/tire longitudinal interaction

Combined longitudinal and lateral control for automated vehicle guidance

Sensitivity study of dynamic systems using polynomial chaos

Driver-aid system using path-planning for lateral vehicle control ☆

Process for the automatic determination of speed limitations on a road and an associated system