This paper presents a novel technique that allows for both computationally fast and sufficiently plausible simulation of vehicles with non-deformable tracks. The method is based on an effect we have called Contact Surface Motion. A comparison with several other methods for simulation of tracked vehicle dynamics is presented with the aim to evaluate methods that are available off-the-shelf or with minimum effort in general-purpose robotics simulators. The proposed method is implemented as a plugin for the open-source physics-based simulator Gazebo using the Open Dynamics Engine.
In agriculture and military research, the track-soil interaction is of high interest (mainly due to sinkage of the track plates). Most of these works seem to only consider planar motion of the vehicle @cite_3 @cite_2 @cite_14 and mainly concentrate on computing correct sinkage-induced behavior. Yamakawa and Watanabe @cite_17 provide a fully three-dimensional simulation taking into account the track-soil interactions and wheel suspension.
@cite_14 @cite_17 @cite_3 @cite_2
2169761102 2071529051 2074462567 2044410627
Abstract Currently available models for dynamic simulation of tracked vehicles usually include super-elements to describe the tracks and the suspension systems. In these models, the dynamics of the track, the interaction between each track link and the ground, and their effect on the vehicle dynamics cannot be considered properly. The rapid increase in computing speed enables the utilization of more complex models, including numerous bodies and force elements. A three-dimensional multi-body simulation model for simulating the dynamic behavior of tracked off-road vehicles was developed using the LMS-DADS simulation program. The model incorporates detailed description of the track, the suspension system, and the dynamic interaction between its components. The bodies of the model are the chassis, the wheel-arms, the wheels, and each track link. Three-dimensional contact force elements are used to describe the interaction of the track links with the vehicle's road wheels, sprocket, and idler. Additional force elements are used to simulate the bump stops and the dampers. User-defined force elements are used to describe the interaction between each track link and the ground. The normal and tangential forces are calculated using classical soil mechanics equations, such as Bekker and Janosi correlations. Sinkage and slip are calculated separately for each track link. Alternative correlations, based on recent studies of the dynamic variations of these forces, can also be used. The model was first applied to the M113 armored carrier. Simulation results under various road conditions were compared with the results of a super-element-based model. It was concluded that the influence of the track dynamics and the soil–link interaction on the vehicle dynamics can be better predicted with the newly developed model. A spatial motion analysis model for high-mobility tracked vehicles was constructed for evaluation of ride performance, steerability, and stability on rough terrain. Ordinary high-mobility tracked vehicles are equipped with independent torsion bar type suspension system, which consists of road arms and road wheels. The road arm rotates about the axis of torsion bar, and rigidity of the torsion bar and cohesion of damper absorb sudden force change exerted by interaction with the ground. The motion of the road arms should be considered for the evaluation of off-road vehicle performance in numerical analysis model. In order to obtain equations of motion for the tracked vehicles, the equations of motion for the vehicle body and for the assembly of a road wheel and a road arm were constructed separately at first. Two sets of equations were reduced with the constraint equations, which the road arms are mechanically connected to the vehicle body. The equations of motion for the vehicle have been expressed with minimal set of variables of the same number as the degrees of freedom for the vehicle motion. We also included the effect of track tension in the equations without constructing equations of motion for the tracks. Numerical simulation based on the vehicle model and experiment of a scale model passing over a trapezoidal speed bump were performed in order to examine the numerical model. It was found that the numerical results reasonably predict the vehicle motion. A new approach to the dynamic modelling of tracked vehicles is proposed in this paper, resulting in a 3D, 8 degrees of freedom dynamic model of an agricultural tracked vehicle, having the two independently applied sprocket torques as input variables. The main features of the approach are a new dynamic model of the shear displacement and the adoption of an innovative modelling and simulation environment: MOSES, based on Object-Oriented tools and techniques. Simulation results are reported for a qualitative validation of the model. Abstract In recent years virtual dynamic system simulation has become very important in the design and development stage, as new strategies can be examined without expensive measurements and with reduced time. This paper describes the development of a simulation model for transient analysis of the longitudinal dynamics of a heavy tracked vehicle. The driving inputs for this simulation model are obtained from a powertrain model. The main elements of the powertrain include the engine, Torque Converter (TC), transmission and drivetrain. Here the engine is modeled based on the engine maps from steady-state experiments. The TC is modeled based on its characteristic map from experiments. A fairly simple transmission model is used which is based on static gear ratios assuming small shift times. The final drivetrain model however includes the rotational dynamics of the sprocket. The simulation model developed is validated by comparing the predicted values with the measured data from experiments. The results have demonstrated that the developed model is able to predict fairly accurately the acceleration and braking performance of the heavy tracked vehicle on both soft and hard terrain.