On the mobility of all-terrain rovers

Purpose – The purpose of this paper is to evaluate the locomotion performance of all-terrain rovers employing rocker-type suspension system. Design/methodology/approach – In this paper, a robot with advanced mobility features is presented and its locomotion performance is evaluated, following an analytical approach via extensive simulations. The vehicle features an independently controlled four-wheel-drive/4-wheel-steer architecture and it also employs a passive rocker-type suspension system that improves the ability to traverse uneven terrain. An overview of modeling techniques for rover-like vehicles is introduced. First, a method for formulating a kinematic model of an articulated vehicle is presented. Next, a method for expressing a quasi-static model of forces acting on the robot is described. A modified rocker-type suspension is also proposed that enables wheel camber change, allowing each wheel to keep an upright posture as the suspension conforms to ground unevenness. Findings – The proposed models can be used to assess the locomotion performance of a mobile robot on rough-terrain for design, control and path planning purposes. The advantage of the rocker-type suspension over conventional spring-type counterparts is demonstrated. The variable camber suspension is shown to be effective in improving a robot’s traction and climbing ability. Research limitations/implications – The paper can be of great value when studying and optimizing the locomotion performance of mobile robots on rough terrain. These models can be used as a basis for advanced design, control and motion planning. Originality/value – The paper describes an analytical approach for the study of the mobility characteristics of vehicles endowed with articulated suspension systems. A variable camber mechanism is also presented.