In order to increase the effectiveness of robotic systems, the robots must be able to negotiate a variety of terrains. In urban environments this task becomes challenging as environments built for humans often have impediments such as stairs and thresholds which may be difficult or impossible for wheeled or tracked vehicles to go over. This is further complicated in search and rescue scenarios where debris and rubble from collapsed structures may further complicate the environment. In order to address these limitations a novel robotic platform, the Loper, has been developed. The Loper utilizes a Tri-lobe wheel and a compliant chassis in order to traverse difficult terrain. In addition, multiple gait configurations of the Tri-lobe wheel enable the Loper to overcome a variety of obstacles, both indoors and out.

The purpose of this paper is to describe the Loper, a multi-purpose robotic platform under development at the University of Minnesota's Center for Distributed Robotics. Leper's unique Tri-lobe wheel design and highly compliant chassis make the platform especially suited for overcoming many of the challenges associated with search operations in urban settings. The mechanically simple design and use of commercially available components make Loper easily maintainable. The platform also features long operational time, onboard sensor processing, dedicated motion control, and four reconfigurable sensor bays.