Vehicle Simulation System: Controls and Virtual-reality-based Dynamics Simulation

Abstract: This paper introduces a cable-suspended robot, the Vehicle Simulation System, designed for pilot and driver training. The main idea of this work is to make a system that will provide realistic simulations of vehicle motion using virtual reality and a motion platform. A method to produce inertial forces acting on the vehicle user is proposed. A detailed description of the robot’s dynamics constraints is provided, accompanied with a numerical solution. Using the developed mathematical model, the robot workspace is analyzed, as well as the influence of the end-effector orientation angle ranges on the available workspace. Adequate robot platform motion is provided through four control systems in a form of a cascade control with a fuzzy logic controller in outer loops. The cable robot is non-linear and difficult from a classical control point of view, since it requires a local linearization of the dynamics equations. A fuzzy logic control concept has been applied in order to control the end-effector position, velocity and acceleration and it turns out to be convenient in simulation, allied with inner-loop classical control. As the system is under-constrained, with 9 unknown cable tensions and 6 dynamics equations, an optimization method is used. The control complexity is increased by the requirement, specific to cable robots, of maintaining positive cable tensions. The system simulations are done using a virtual reality environment and results are presented accompanied with the discussion.