Abstract

Wheel loads are one of the most sought-after inputs for durability evaluation of chassis and suspension system in off-highway agricultural vehicles. Collecting wheel loads through physical test is cumbersome in terms of time, cost, and efforts. Instead, usage of a simulation-based approach to predict accurate wheel loads during early phase of product development has lot of usefulness and benefits. This paper will talk in detail about using an Integrated Multiphysics Multibody Dynamics Simulation Model with Hydrostatic Transmission and Embedded Software for off highway vehicle which is also called CommandDrive powertrain that consists of a single pump which sends flow to all four variable displacement motors separately to drive all four wheels. If one or more wheels loose traction, the system will adjust to slow the wheels that are slipping and direct more flow to the remaining wheels to retain all wheel drive. In this paper, a comparison of simple to advanced level of simulation integrated model for predicting wheel loads on a Self-Propelled Sprayer during a turning operation will be presented. During a turn, rpm of inner wheel will be less than the rpm of outer wheel. This is because the inner wheel travels less distance as compared to outer wheel. To capture the turning phenomenon accurately, different fidelity levels of integrated models including Hydrostatic Transmission or Embedded Software and their pros and cons will be discussed as below: 1. All wheel’s same speed input driven vehicle level Rigid MBD model – Traditional Approach 2. Vehicle speed input driven Hydrostatic transmission equivalent Mechanical drivetrain full vehicle model 3. Hydrostatic transmission integrated vehicle Multiphysics model 4. Integrated Multiphysics Multibody Dynamics Simulation Vehicle Model with Hydrostatic Transmission and Embedded Software The effect and significance of Multiphysics integrated simulation model’s increased fidelity would then illustrate enhanced wheel loads correlation with respect to test data and show importance of integrated modeling approach.