Analysis of Drifting for a Remotely Controlled Car
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AbstractBy restricting a vehicle to the linear region of operation, with a small sideslip angle, a vehiclecannot achieve its full potential. By entering the nonlinear region of operation tightercorners can be achieved and some accidents could be prevented. Research is currently beingconducted to introduce drifting into vehicle safety systems, which currently restrict thevehicle to the linear region of operation. Vehicle drifting has been shown to have unstableequilibria, while still maintaining controllability.In this thesis, equilibria with sideslip angles ranging from -30 degrees to 30 are found fora nonlinear two-track model simulator. Analysis showed that simple mappings could bemade between the states and the inputs, and between the states themselves. All the linearisedsystems in these equilibria were found to be unstable, which coincides with currentresearch.In addition, this thesis presents an adaptive backstepping controller, which is used for convergeto an arbitrary sideslip angle, and when the drift is being initialised the controllermimics the behaviour of Power Over drifting technique. The adaptive part of the backsteppingcontroller is used as integral action that, by the use of adaptation, finds the stationarydeviation between the yaw rate and the desired yaw rate, which is added to the control law.A mapping between the desired sideslip angle and the desired yaw rate is used in a feedforward term such that the desired sideslip angle is achieved when the yaw rate converges.The controller has been tested with a modified Line Of Sight guidance system which providedthe controller with a desired sideslip angle. Robust response with respect to changesin vehicle mass and inertia was observed.