Modeling and simulation of a vehicle with automatic transmission

2. Plant model: Driver & Environment

The Driver and Environment Xcos models are relatively simple. The Driver model outputs the profile in time of the accelerator and brake pedals position. The Environment model outputs the time profile of the road slope (gradient).

The decision on what profile is used for the simulation is done by setting the right value for the parameter DrvgMod_z_C. This parameters decides the simulation scenario, by switching through a multiport switch (Dynamic index).

Driver and Environment - Xcos block diagram

Image: Driver and Environment – Xcos block diagram

As you can see, there are no inputs into the Driver and Environment model. The parameters and outputs are defined in the tables below.

Parameters

NameValueDescription
DrvgMod_z_C1Sets the simulation scenario: 1 – Acceleration, 2 – Braking, 3 – Hill climb

Outputs

NameValueDescription
AccrPedlPosn_prcAcceleration pedal position in [%]
BrkPedlPosn_prcBrake pedal position in [%]
EnvRoadSlop_prc –Road slope (gradient) in [%]

In order to avoid high jumps in the signal, which can not happen in a real driving situation, all outputs are filtered using a first-order transfer function (low-pass filter). The outputs are also fed into global GOTO blocks in order to be saved in the Scilab workspace.

2.1 Full acceleration

The first driving mode for the simulation is a full acceleration scenario.

Driver and Environment full acceleration - Xcos block diagram

Image: Driver and Environment full acceleration – Xcos block diagram

The accelerator, brake pedal and road slope are generated into a signal builder block, Sigbuilder. The parameters are defined in the Scilab workspace. All three signals are the multiplexed using a MUX block. The reason for multiplexation is just to avoid having to use multiple Dynamic index blocks, one for each signal.

Parameters

NameValueDescription
AccrPedlPosnProfTi1_s_X[0;1;1.01;tf]Acceleration pedal position time profile axis
AccrPedlPosnProf1_prc_Z[0;0;100;100]Acceleration pedal position time profile map
BrkPedlPosnProfTi1_s_X[0;tf]Brake pedal position time profile axis
BrkrPedlPosnProf1_prc_Z[0;0]Brake pedal position time profile map
EnvRoadSlopProfTi1_s_X[0;tf]Road slope (gradient) time profile axis
EnvRoadSlopProf1_prc_Z[0;0]Road slope (gradient) time profile map

2.2 Braking

The Xcos block model for the braking scenario is the same as for the acceleration scenario. The only difference is in the parameters setup.

Parameters

NameValueDescription
AccrPedlPosnProfTi2_s_X[0;5;10;15;20;40;45;tf]Acceleration pedal position time profile axis
AccrPedlPosnProf2_prc_Z[0;0;60;60;0;0;40;40]Acceleration pedal position time profile map
BrkPedlPosnProfTi2_s_X[0;20;25;35;40;tf]Brake pedal position time profile axis
BrkrPedlPosnProf2_prc_Z[0;0;35;35;0;0]Brake pedal position time profile map
EnvRoadSlopProfTi2_s_X[0;tf]Road slope (gradient) time profile axis
EnvRoadSlopProf2_prc_Z[0;0]Road slope (gradient) time profile map

2.3 Hill climb

The Xcos block model for the hill climb scenario is the same as for the acceleration scenario. The only difference is in the parameters setup.

Parameters

NameValueDescription
AccrPedlPosnProfTi3_s_X[0;1;2;10;30;tf]Acceleration pedal position time profile axis
AccrPedlPosnProf3_prc_Z[0;0;30;30;20;20]Acceleration pedal position time profile map
BrkPedlPosnProfTi3_s_X[0;tf]Brake pedal position time profile axis
BrkrPedlPosnProf3_prc_Z[0;0]Brake pedal position time profile map
EnvRoadSlopProfTi3_s_X[0;5;10;10.01;tf]Road slope (gradient) time profile axis
EnvRoadSlopProf3_prc_Z[0;0;0;12;12]Road slope (gradient) time profile map

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