Seite - 23 - in Integration of Advanced Driver Assistance Systems on Full-Vehicle Level - Parametrization of an Adaptive Cruise Control System Based on Test Drives

2.4. ACC Controller sensors env.-rec. HMI setτ,setv controller upper lev. controller lower lev. vehicle desa du ACCcontrollerACC-SCU cx buxavxvv OTFr˙s,OTFrs Figure 2.14.: ACC controller structure, adapted from [WWL+04] information about the vehicle state, xc, which contains the yaw rate vωz, the steering wheel angle δSW, the longitudinal vax and lateral accelerations vay, etc. Figure 2.14 shows this controller structure. 2.4.1. Longitudinal Vehicle Dynamics Unless otherwise indicated, the following chapter is based on [HW09] and [HW10]. Fig- ure 2.15 shows the coordinate systems used. The global coordinate system (0x,0y,0z) is fixed on the ground, and the vehicle coordinate system (vx,vy,vz) is fixed to the vehicle body, with its origin in the CG of the vehicle. The sensor coordinate system (sx,sy,sz) ismountedonthevehiclebodyaswell, with theoriginatpointS. Thecentre coordinate system (cx,cy,cz) has its origin at the centre of the wheel, where the cx-axis is parallel to the ground plane, and the cy-axis is the rotation axis of the tyre. In the middle of the contact patch between tyre and ground, theW-point is the origin of the (wx,wy,wz) coordinate system, where thewx-axis is parallel and thewz-axis is perpendicular to the ground plane. Figure2.16 shows thekineticquantities in the longitudinaldirection for thevehiclebody, one front and one rear wheel. To find the equation of motion for all three bodies, the linear momentum is used. For the vehicle body, it reads mB vv˙x= 2 cfFx+2 crFx−FβB−Fa, (2.12) wheremB describes the vehicle body mass. The climbing resistance is given by FβB=mB g cosβ, (2.13) and the air drag reads Fa= 1 2 caAxρa vv 2 x. (2.14) The air drag depends on the drag coefficient ca, the frontal projection areaAx of the vehicle, the density of the air ρa, and the quadratic to the longitudinal speed vvx. The 23