Simcenter Amesim How to model vehicle and trailer on a slope in Simcenter Amesim
Summary
The article analyzes an example where a vehicle and trailer are on a slope in "park mode"
Details
Vehicle models have been introduced in the Powertrain library in order to model the global powertrain system. Different levels of complexity answer to the different challenges in powertrain design such as performances and losses, comfort and NVH.
Three different groups of vehicle models are available in the Powertrain library. In the one dimension (1D) models only the longitudinal motion of the vehicle is taken into account. In the two dimensions (2D) models both longitudinal and vertical motions are computed. The 1D vehicle models are dedicated to performance and consumption issues whereas the 2D vehicle models must be preferred for comfort analysis.
In the three dimensions (3D option) one can also study the roll motion. This is particularly interesting for longitudinal engine layouts as the engine creates torque in the roll axis direction of the carbody.
This type of analysis is particularly useful when the user want to analyze the impact of having a trailer attached to the vehicle on the vehicle dynamics. This demo can be a starting point for further complex analyses including the interactions between vehicle dynamics, traction and the powertrain.
In this article we will be focusing on 1D vehicle model with the tires when a trailer is connected to it as shown below:
As you can see in the picture, the slope is defined both to the vehicle and the trailer. However, from the equations in the documentation, it can be found that the slope force is already calculated using the vehicle and the trailer mass combined as shown below:
Therefore, no input of slope is required to be connected to the trailer and the slope connection to the vehicle body takes into account the trailer mass as well, as shown below with zero slope input for the trailer.
This example is meant to be illustrative of the basic interactions between engine / driveline / chassis / tires that you can capture with Amesim. A tractor pulling a trailer is a good example but we mainly wanted to show large clear effects. For example the bumps are +-5cm with a wavelength about twice the wheelbase: you would probably drive more carefully when pulling a trailer on such a ground when you will include the vehicle motion.