Combining Coordination of Motion Actuators with Driver Steering Interaction

Abstract

Objective: A new method is suggested for coordination of vehicle motion actuators; where driver feedback and capabilities become natural elements in the prioritization.Methods: The method is using a weighted least squares control allocation formulation, where driver characteristics can be added as virtual force constraints. The approach is in particular suitable for heavy commercial vehicles that in general are over actuated. The method is applied, in a specific use case, by running a simulation of a truck applying automatic braking on a split friction surface. Here the required driver steering angle, to maintain the intended direction, is limited by a constant threshold. This constant is automatically accounted for when balancing actuator usage in the method.Results: Simulation results show that the actual required driver steering angle can be expected to match the set constant well. Furthermore, the stopping distance is very much affected by this set capability of the driver to handle the lateral disturbance, as expected. Conclusion:In general the capability of the driver to handle disturbances should be estimated in real-time, considering driver mental state. By using the method it will then be possible to estimate e.g. stopping distance implied from this. The setup has the potential of even shortening the stopping distance, when the driver is estimated as active, this compared to currently available systems. The approach is feasible for real-time applications and requires only measurable vehicle quantities for parameterization. Examples of other suitable applications in scope of the method would be electronic stability control, lateral stability control at launch and optimal cornering arbitration.

Coordination of motion actuators in heavy vehicles using Model Predictive Control Allocation

“…The opposite would be to prioritise stopping distance only, which has a trivial solution. A deeper analysis of what states to ultimately prioritise can be found in [4]. As the potential of MPCA is to predict the behaviour of the actuators and their influence on the vehicle, .…”

“…Control allocation (CA) methods have been extensively exploited to conveniently combine the use of the motion actuators, see e.g. [1][2][3][4]. A CA method for an over-actuated vehicle uses a modular architecture for the control where a high-level motion controller computes the resulting forces and moments on the vehicle requested to cope with a specific manoeuvre.…”

Yapısal Döküm Parçaların Yorulma Ömrünü Etkileyen Ana Faktörlerin Ağır Ticari Araç Fren Sistemlerinde İncelenmesi

“…Frenlerin hasar görmesi halinde araçta sağa veya sola çekme, şerit dışına taşma, gerekli frenleme ivmesini oluşturamama gibi sorunlar görülebilmektedir. Normal kullanımda frenler arasında oluşabilecek fren kuvvetleri düşük olduğundan sürücünün bunu direksiyon girdisi ile bertaraf etmesi beklenirken, ani kırılma ve fren kaybı durumunda kaza ihtimali artmaktadır [4].…”

Advanced emergency braking under split friction conditions and the influence of a destabilising steering wheel torque

“…The most straightforward approach to ensure that the vehicle does not leave its intended lane would be to limit the usage of brakes, in a split-µ situation, based on an estimate of the driver's ability to handle the yaw disturbance. A method for this is proposed in [9]. It does however result in a substantially longer stopping distance when the driver is assumed to be passive, as a restrictive approach must apply when using brakes.…”