Knowledge Base

Article Number: 110 | VC6 | VC5 | VC4 | VC3 | Post Date: February 23, 2024 | Updated: February 23, 2024

What is the difference between using “Wheels Separately” and “Locked Wheels” in a simulated vehicle’s sequences menu?

The definitions of these simulation sequence options are given below and can also be found in the Short Glossary. Before continuing, we recommend reviewing the User’s Guide (VC6 | VC5 | VC4 | VC3).

Lock wheels

For simulated vehicle motion, "lock wheels" can be found in the "sequences" menu and is an option for all sequence types. When enabled, the "lock wheel ratio" input field will become available for each vehicle wheel. Ratio 1 corresponds to axle 1's driver-side wheel, ratio 2 to axle 1's passenger-side wheel, ratio 3 to axle 2's driver-side wheel, and so on. The ratio value represents the percent of maximum tire braking force to be applied at each time-step while the given sequence is active. The lock wheel effect begins on the integration time-step (no lag) where activated by the sequence's time or distance value.


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Wheels separately

For simulated vehicle motion, "wheels separately" is available in the "sequences" menu and is an option for sequence types deceleration, acceleration, and accel. backward. When enabled, the "ratio" input field becomes available for each vehicle wheel. Ratio 1 corresponds to axle 1's driver-side wheel, ratio 2 to axle 1's passenger-side wheel, ratio 3 to axle 2's driver-side wheel, and so on. The wheels separately ratio values serve the same function as “pedal position” for the given sequence type but allow the user per wheel control. Recall “pedal position” specifies the percent of maximum longitudinal tire force to be applied in the vehicle’s forward direction for sequence “type: acceleration” and backward direction for “type: accel backward”, for the vehicle’s drive wheels at each time-step where the given sequence is active. For “type: deceleration”, “pedal position” specifies the percent of maximum longitudinal tire braking force to be applied at each time-step while the given sequence is active. Similar to “pedal position”, when “wheels separately” is enabled with “type: deceleration”, a given wheel’s ratio will linearly increase from the prior sequence’s value to the new target value over a time equal to the “brake lag” input. Braking via “pedal position” or “wheels separately” ratios will engage whenever the vehicle’s speed exceeds “min v”; otherwise, it will disengage (that is, the ratios go to 0). For “type: acceleration” and “type: accel backward”, the “pedal position” or “wheels separately” ratios will engage whenever the vehicle’s speed drops below “max v” otherwise the ratios go to 0.

Note, for sequence “type: deceleration”, if both “lock wheels” and “wheels separately” are enabled, for a wheel \(i\), the ratio used at any given time-step will be max(lock wheel ratio \(i\), wheel separate ratio \(i\)), where the wheel separate ratio \(i\) value is a function of time, brake lag, and min v. For sequence “type: acceleration” and “type: accel backward”, if both “lock wheels” and “wheels separately” are enabled for a given wheel \(i\), and the lock wheel ratio \(i\) is non-zero, then that ratio will be used to apply a braking force for that wheel.

For more information, see the User’s Guide (VC5 | VC4 | VC3)


Tags: Pedal position, wheels separately, lock wheels, ratios, sequences.


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