Off-road handling of a mini baja vehicle

Winnaar, Kyle Thomas

Off-road handling of a mini baja vehicle

dc.contributor.author	Winnaar, Kyle Thomas
dc.date.accessioned	2018-06-06T08:40:02Z
dc.date.available	2018-06-06T08:40:02Z
dc.date.issued	2017
dc.description	A dissertation submitted to the Faculty of Engineering and the Built Environment, University of the Witwatersrand, Johannesburg, in fulﬁlment of the requirements for the degree of Master of Science in Engineering.	en_ZA
dc.description.abstract	The primary focus of vehicle dynamics studies have been the handling capabilities and suspension design of a vehicle to achieve the optimal road holding capability and ride comfort level. Numerous studies have focussed on the design, modelling and optimisation for on-road vehicle suspensions, but the study of vehicle dynamics on oﬀ-road surfaces is still relatively new. The objectives of this dissertation were to characterise the steady-state cornering response for on-road and oﬀ-road surfaces, evaluate the open-loop vehicle response using the step-steering input manoeuvre, and evaluate the closed-loop vehicle response using the double lane change (DLC) manoeuvre of a mini baja vehicle. The mini baja vehicle was instrumented with an inertial measurement unit (IMU) to measure vehicle accelerations and yaw rate, a steering angle sensor, throttle and brake position sensors, and a wheel speed sensor to measure rear wheel angular velocity. A tarmac surface was used as a control test surface, while grass and dirt track surfaces oﬀered decreasing tyre grip levels, resulting in larger sideslip. The handling on the tarmac surface was repeatable for all the cornering tests performed. On the grass and dirt track surface, tyre grip levels decreased, resulting in an increase in steering variability when exposed to transient cornering. On the grass surface, the tyres were able to generate suﬃcient lateral force to obtain understeer up to a maximum lateral acceleration of 0.6 g. Up to a maximum lateral acceleration of 0.35 g, the tyre grip level was still suﬃcient that the handling was stable on the grass and dirt track surfaces as compared to on the tarmac surface. On the dirt track surface, the tyre traction decreased at a lateral acceleration of 0.35 g and the vehicle exhibited oversteer at a maximum lateral acceleration of 0.39 g. The tyres were unable to develop suﬃcient lateral force on the dirt track surface for high lateral acceleration manoeuvres. When performing transient cornering, the ability of the tyres to develop a lateral force had the biggest inﬂuence on handling on surfaces which oﬀered low tyre traction.	en_ZA
dc.description.librarian	GR2018	en_ZA
dc.format.extent	Online resource (46 leaves)
dc.identifier.citation	Winnaar, Kyle Thomas, (2018) Off-road handling of a mini baja vehicle, University of the Witwatersrand, Johannesburg, https://hdl.handle.net/10539/24615
dc.identifier.uri	https://hdl.handle.net/10539/24615
dc.language.iso	en	en_ZA
dc.subject.lcsh	Automobiles--Design and construction
dc.subject.lcsh	Motor vehicles--Dynamics
dc.title	Off-road handling of a mini baja vehicle	en_ZA
dc.type	Thesis	en_ZA