Recent trends in automotive crash statistics suggest a dual role of technology in both saving and threatening the lives of American drivers. Advancements in automotive safety like Anti-Lock Braking Systems and Electronic Stability Control have led to a significant reduction in automotive fatalities over the last decade. However, the ubiquity of technology, mainly the cellular phone, has led to a dramatic increase in fatalities attributed to distracted driving. To address this challenge, auto manufacturers are empowering modern vehicles with even more technology.
Driver Assistance and Augmentation Systems
Automobile drivers frequently encounter changes in vehicle handling properties that require them to adjust their steering control actions. These changes may be benign, such as slightly different steering ratios in different cars, or potentially life-threatening, such as suddenly encountering a patch of black ice on the roadway. Understanding how drivers adapt to such handling changes is important for informing the design of new driver assistance systems and training methods.
The question of what kind of torque to create on a FFB steering system for a steer-by-wire vehicle is a broad one. As a first step, since steer-by-wire vehicles have no inherent steering feel like conventional steering vehicles, creating an artificial steering feel is important. This allows a steer-by-wire vehicle to `feel' like a conventional steering vehicle and gives the driver the same kinds of information that he is used to getting from those vehicles.
Creating Predictive Haptic Feedback For Obstacle Avoidance Using a Model Predictive Control (MPC) Framework
New sensing technologies allow modern vehicles to perceive the environment around them even when human visual perception is limited due to poor lighting or fog. Steerby-wire technology enables active steering capability in which the driver’s command to the roadwheels is augmented for maintaining safety. Predictive controllers can leverage both of these technologies to create shared control safety systems that work with the driver to ensure a safe and collision-free vehicle trajectory.
This paper presents a vehicle handling modification approach that tracks the dynamics of a general nonlinear planar reference model. The control structure is a combination of linear and nonlinear state feedback with feedforward of reference model yaw moment, lateral force, and longitudinal force at the vehicle center of gravity. The modified closed-loop system is demonstrated to be stable and has robust tracking performance to reasonable levels of model uncertainty.
Low friction surfaces such as ice are challenging for drivers to navigate safely because the limited tire force capability drastically alters the vehicle dynamics compared to dry roads. Experiments on real or emulated low friction surfaces are important for testing control systems, understanding driver-vehicle interactions, and training drivers. As a way of enabling these experiments with the added flexibility of a tunable friction coefficient, this paper presents a forcebased approach to emulating the lateral dynamics of a vehicle on a low friction surface using four-wheel steer-by-wire.
Active safety systems enabled by steer-by-wire technology can share control with a driver, augmenting the driver’s steering commands to avoid collisions and prevent loss of control. The extent to which this can be done is limited by the controller’s ability to anticipate dangerous scenarios in order to appropriately intervene and steer the vehicle to safety. However, the non-linear nature of tire dynamics poses a challenge in predicting and modifying vehicle behavior in real-time.
Drivers use torque feedback at the handwheel of a vehicle, or steering feel, to obtain information about the road and tire dynamics. This aids them in driving tasks like curve negotiation. Steer-by-wire vehicles, due to the mechanical decoupling of the front tires and handwheel, do not have any inherent steering feedback and require an artificial steering feel. One way to implement an artificial steering feel is to synthesize steering feedback with a model running on board the vehicle.