Modeling and Simulation of a Four-Wheel-Steered Agricultural Robotic Vehicle

Abstract

A four-wheel-steered (4WS), four-wheel-driven (4WD) small agricultural robotic vehicle(AgRV) is under development in Agricultural Robotics Laboratory at the Iowa State University. Thispaper presents the modeling of a 4WS/4WD AgRV platform to assess its dynamic behavior andstability through simulation. The simulation was implemented using Matlab Simulink andSimMechanics toolboxes. The vehicle was simulated considering three translational and threerotational degrees of freedom of the vehicle body. The steering performance of the vehicle for bettermaneuverability was studied using coordinated, crab and conventional steering systems. In thedeveloped model, side slips, lateral acceleration of the vehicle, slip angle and the lateral forcegenerated on each of the four wheels during the simulation were analyzed for the dynamic stabilityevaluation of the vehicle. The extensive modeling and simulation of the vehicle will aid the designand finally the development of an AgRV navigational controller.