Tip-over stability of manipulator-like mobile hydraulic machines

This paper describes the development of a simulation model for studying the tip-over stability of a typical heavy-duty hydraulic log-loader machine. The model takes into account the dynamics of (i) the base that can potentially rock back and forth, (ii) the combined vehicle suspension and ground/tire compliance, (iii) the friction between the tires and the ground, and (iv) the hydraulic actuators' functions. The results demonstrate the effects of the manipulator movements, the flexibility of the contact between the base and the ground, the hydraulic compliance, and the friction properties between the wheels and the ground, on the stability of the machine. Particularly, it is shown that the flexibility of the contact between the base and the ground reduces the machine stability, whereas the flexibility at the manipulator joints due the hydraulic compliance improves the machine stability.