State Estimator Design for Real-time Controlled Restraint Systems Citation for published version (APA): State Estimator Design for Real-time Controlled Restraint Systems

Abstract-In this paper, a method is presented to estimate the motion of a vehicle occupant in frontal impact. Knowledge of the occupant's motion during a crash can significantly reduce the risk of injury, as restraint systems could be real-time adapted to the optimal settings. It is shown that the chest acceleration of the occupant, an important measure of injury, is accurately estimated by filtering of the belt displacement at the retractor side. Low order, nonlinear models are constructed from complex models, and a state estimator filter is designed using a linearization of these low order models

Continuous restraint control systems: safety improvement for various occupants

Occupant safety can be significantly improved by continuous restraint control systems. These restraint systems adjust their configuration during the impact according to the actual operating conditions, such as occupant size, weight, occupant position, belt usage and crash severity. In this study, the potential of a controlled restraint system is demonstrated. First, an overview is given of the problems concerning the sensors, actuators and control strategy of such a system, and solutions are given. Next, a numerical demonstrator is developed, which includes a dummy and vehicle model, and a realistic implementation of the components of the controlled restraint system. The demonstrator is subjected to different loading conditions, and the results are compared to a reference model. This reference model contains a conventional restraint system with optimized settings, and it has been validated against sled test experiments. Simulation results with the demonstrator indicate that significant injury reduction can be achieved with continuous restraint control systems

Improving continuously variable transmission efficiency with extremum seeking control

The design of an efficiency optimal controller for the variator in a vehicular continuously variable transmission is studied. A conventional controller aims at tracking a prescribed reference for the transmission ratio and at preventing damage, but does not address efficiency. Sufficiently accurate models for the efficiency as function of the clamping forces are not available, whereas measurement of the efficiency requires extra sensors. In this brief, a controller is proposed that improves the efficiency without needing extra sensors. The maps between the clamping forces (input) and the efficiency or the speed ratio (output) are studied with test rig experiments. These maps exhibit a maximum, but the location of this maximum is uncertain. So, an extremum seeking controller is developed. This controller can adapt the input to maximize the output, without needing a model. Experiments show that this approach is feasible and that a conventional controller is outperformed. A robustness analysis for disturbances indicates that these are effectively handled