Online automatic tipover prevention for mobile manipulators

Mobile manipulators operating in field environments are susceptible to dangerous and costly rollover or tipover instabilities, particularly when operating on an uneven terrain or when exerting large forces or moments. By monitoring the static and dynamic tipover stability margins of a mobile manipulator it is possible to predict such tipover and take appropriate actions to prevent the tipover from occurring. This paper describes a scheme for automatic tipover prediction, and prevention, which uses the static and dynamic force-angle measures of tipover stability margin. Time-until-tipover prediction is accomplished using estimated gradients of the tipover stability margins, and prevention is accomplished using a combination of the manipulator and platform actuators. Simulation results demonstrate the efficiency and promise of the proposed scheme for automatic tipover prevention.