Travel over sloped terrain is difficult as an incline changes the interaction between each wheel and the ground resulting in an unbalanced load distribution which can lead to loss of traction and instability. This paper presents a novel approach to generating wheel rotation for primary locomotion by only changing its centre of rotation, or as a complimentary locomotion source to increase versatility of a plain centre hub drive. This is done using linear actuators within a wheel to control the position of the centre hub and induce a moment on the wheel from gravity. In doing so our platform allows for active ride height selection and individual wheel pose control. We present the system with calculations outlining the theoretical properties and perform experiments to validate the concept under loading via multiple gaits to show motion on slopes, and sustained motion over extended distance. We envision applications in conjunction to assist current motor drives and increasing slope traversability by allowing body pose and centre of gravity manipulation, or as a primary locomotion system.

This paper proposes a novel configurable wheel that exhibits desired properties of varied radius wheels. Positional manipulation of the centre hub is proposed and tested to achieve these desired characteristics of `virtual' wheels in a physical system. The centre hub is manipulated via the use of pneumatic actuators mounted to and constricted by the outer rim of the wheel, which allows for fast and accurate control to enable the vehicle ride height and gear ratio to be adjusted continuously and be maintained during the wheels' full rotation. Experiments are presented, validating this ability of the system. We envision uses for this system to extend from off-road robotics to space exploration as these wheels exhibit novel characteristics not demonstrated by other platforms.

Three-dimensional perception is a key technology for many robotics applications, including obstacle detection, mapping, and localization. There exist a number of sensors and techniques for acquiring 3-D data, many of which have particular utility for various robotic tasks. We introduce a new design for a 3-D sensor system, constructed from a 2-D range scanner coupled with a passive linkage mechanism, such as a spring. By mounting the other end of the passive linkage mechanism to a moving body, disturbances resulting from accelerations and vibrations of the body propel the 2-D scanner in an irregular fashion, thereby extending the device's field of view outside of its standard scanning plane. The proposed 3-D sensor system is advantageous due to its mechanical simplicity, mobility, low weight, and relatively low cost. We analyze a particular implementation of the proposed device, which we call Zebedee, consisting of a 2-D time-of-flight laser range scanner rigidly coupled to an inertial measurement unit and mounted on a spring. The unique configuration of the sensor system motivates unconventional and specialized algorithms to be developed for data processing. As an example application, we describe a novel 3-D simultaneous localization and mapping solution in which Zebedee is mounted on a moving platform. Using a motion capture system, we have verified the positional accuracy of the sensor trajectory. The results demonstrate that the six-degree-of-freedom trajectory of a passive spring-mounted range sensor can be accurately estimated from laser range data and industrial-grade inertial measurements in real time and that a quality 3-D point cloud map can be generated concurrently using the same data.