Example: DETECT CONTACT Example

 

The DETECT CONTACT VARINC of the Variable time inputs for the m-smac program are provided to reduce the input requirements of the program by allowing a minimum number of inputs for the driver control tables. To use the DETECT CONTACT VARINC option on the previous option you need to do the following:

Set the VARINC option for the table = 2.0. This tells the m-smac program

1) to DETECT CONTACT and that the 1st 2 inputs for the time history table are the PRE-Impact and Post-Impact values

2) That at IMPACT Detection, the control table values will change from PRE-impact to POST-impact over the time period equal to the 2nd time input – 1st time input in the table (se example below)

2) the time increment inputs (field 1 of the tables) are significant and that

3) Field 3 of the Table Header card indicates the number of Table entries to follow.

EXAMPLE#1

The Header of the table indicates that the DETECT CONTACT VARINC is being used (field 6=2.0) and that 2 table inputs are to follow (field 3=2.0).

The 1st line of the braking table is used until contact is detected. So in this instance, there will be no braking.

Once CONTACT DETECTED by the msmac program:

The braking will change from the 1st line to the second line over the time difference between the 1st line and the second line.

So in EXAMPLE#1, the braking for vehicle 1 will change for each wheel as : RF 0 to -1 (locked), LF 0 to 0, RR 0 to -.20 and LR 0 to -.20.

The change will occur over (0.60 – 0.50) = 0.10 seconds (the second entry time minus the 1st entry time) So if CONTACT DETECTED at 0.43 sec of the simulation, the braking change would occur from 0.43 to 0.53 seconds.

EXAMPLE#2:

Lets assume that the CONTACT DETECTED at 1.25 sec of the simulation:

So at 1.25 seconds, the braking for vehicle 1 will change for each wheel as : RF 0 to -1, LF 0 to -1, RR 0 to -1.0 and LR 0 to -1.0

The change will occur over (0.55 – 0.20) = 0.35 seconds (the second entry time minus the 1st entry time)

Which means from 1.25 to 1.60 seconds the braking will change.

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Steer Tables