Design and Testing of Active Suspensions for Wheeled Planetary Rovers

Robotic planetary rovers and human rated rovers used since the beginning of space exploration and planned for the future missions are mostly based on wheels. The wheels are connected with the rover’s body through a suspension system having different tasks, like correctly distributing the load among the various wheels, granting the required terrainability and mobility to the rover and reducing the accelerations the rover‘s body is subjected to due to the motion on uneven ground. The last requirement is much dependent on the speed of the rover and on whether it carries only instruments or also humans. Robotic rovers used up to now, and in particular those operating on Mars, are very slow and the third requirement is only marginal. Due to this reason, suspensions not including elastic and damping elements, like the rocker bogie mechanism, were used. The only human-carrying rover used up to now, the LRV of the Apollo missions, used a double wishbone suspension of automotive derivation. The use of active suspensions is beneficial for all the above mentioned tasks of the suspension mechanism. The present work deals with the development, design and testing of an innovative type of simple active suspension on a demonstration small robotic rover. The innovative layout allows to maintain the rover body level even in case of travelling on strongly uneven ground, while using the suspensions as ‘legs’ to cross obstacles whose height would make them not manageable by a conventional passive suspension.