Effects of different excitation spectra on virtual suspension damper design

Effect of handling characteristics on minimum time cornering with torque vectoring

“…'Perfect', is defined as 'the ability to operate the vehicle at the limit of adhesion at every instant without making errors'. 'Super-human' meaning he has direct authority over individual wheel torques (T ij in (21)). This formulation is used to generate the baseline optimal trajectories for TV in §4.1, and to analyse the effect of passive handling balance on controlled response in §4.2.…”

“…They achieved this by using nonlinear optimal control techniques, which permitted both the ability to gain insight into optimal controls for distribution of torques but also the realistic emulation of a racing driver. Numerous other vehicle dynamics studies using the optimal control technique to manoeuvre vehicles at the performance limit has permitted a realistic emulation of both circuit racing drivers [14][15][16][17][18], and rally trailbraking [19,20]; EV-specific topologies were considered in [13,21,22]. The nonlinear optimal control solution gives an ideal driver behaviour (no mistakes, friction-limit operation, full preview of future conditions)-which is not possible with a causal driver model, racing-line following [16], or model predictive control.…”

“…In this work we propose the application of nonlinear optimal control techniques to study the effect of handling characteristics, passive and actively modified, of torque-vectored vehicles for minimum time manoeuvring. In [21] we generated a particular minimum time open-loop control trajectory over a U-turn for a 7 degree of freedom (DOF) vehicle model with nonlinear tyres and TV via 4 independent motors. The open-loop optimal control problem was formulated with 4 independent wheel torques and front steering rate (corresponding to the driver steering input) as the control inputs.…”

“…The open-loop optimal control problem was formulated with 4 independent wheel torques and front steering rate (corresponding to the driver steering input) as the control inputs. In this paper we extend the open-loop OCP formulation of [21] to study the effect of passive handling balance, determined by the front/rear tyre characteristics, on the controlled performance.…”

“…A framework that included the closed-loop TV controller in the system dynamics for a ground vehicle was first introduced in [22], using, however, a rather simple 3DOF single track vehicle model, with a linear tyre model and neglecting important load transfer effects, while the torque vectoring control action was applied as an external yaw moment. In this work we extend the approach of [22] by considering the 7DOF model with nonlinear tyre characteristics and load transfer effects of [21]. Torque vectoring is now realistically implemented through control of trac-tion/braking forces at each of the 4 wheels independently.…”