Differential braking based sliding mode controller design for un-tripped rollover prevention

Un-tripped rollover accidents caused by sharp steering during high-speed cornering manoeuvres pose significant risks, particularly for vehicles with a high centre of gravity, such as heavy commercial road vehicles. This study uses a lateral load transfer ratio representing the load distribution between the inner and outer tyres to assess rollover criticality using a 4-DoF model. The developed model was corroborated with the simulation results obtained from TruckMaker ® under identical driving manoeuvres and was found to be adequate for controller development. The un-tripped rollover prevention problem is formulated as a yaw rate tracking problem in a sliding mode controller framework, where the external moment is generated using differential braking. The developed algorithm was experimentally evaluated in a hardware-in-loop setup, and the results show that the controller improves roll stability during steering manoeuvres like Fishhook and Sine with Dwell. During the Fishhook and Sine with Dwell manoeuvres, the uncontrolled vehicle completely rolled over at 10.82 and 11.3 s, respectively. LTR exceeded the safe limits for approximately 1.85 and 1.45 s. However, the differential braking-based algorithm maintained the LTR within permissible limits for the controlled vehicle, with stabilization achieved within 0.60 s for both manoeuvres.