Improving directional stability control in a heavy truck by combining braking and steering action

Other conference contribution, 2016

The introduction of electronics in heavy vehicle steering systems has enabled active steering torque support. As steering is an effective way of escaping directional instability and brakes are fast and decoupled from the driver a combination of controlled steering and braking would be beneficial when performing directional stability control. A method is therefore proposed for this, based on control allocation. The method is unique in that it uses combined quadratic lateral and longitudinal tyre constraints computed in real-time, which has the potential of producing a higher corrective yaw moment than the commonly used approach with linear constraints, and that it can be adapted to any heavy vehicle combination. The method has been tested and compared to a standard stability control system in three different manoeuvres using a heavy solo tractor unit on a frozen lake. The measured deviation from the intended path was observed to reduce up to several meters with the new method. Also driver rating improved.