Advantages of Active and Passive Suspension Systems in Obstacle Negotiation for Planetary Rovers

Hybrid locomotion systems with actively controlled wheeled-legged suspension offer high off-road mobility, feature ground adaptation and are capable of overcoming large obstacles. Rovers with passive suspension also have remarkable climbing abilities and are much easier to control. In this paper, experiments on overcoming obstacles with two robots with different suspension systems, one with an active wheeled-legged suspension and one with a passive triple-bogie suspension, are analysed and the advantages and disadvantages for different applications are shown. The control effort of the active suspension significantly slows down the rover in situations that can also be handled with a passive suspension. However, the unique ability of the active suspension to overcome obstacles without contact is a promising feature that requires further research and development to realise its full technological potential for autonomous operation.