We present a two-step iterative algorithm to estimate the trajectory of a hopping rover. In the first step, a monocular scheme of visual odometry is adapted to estimate an initial portion the hopping trajectory. From this, the parameters for the ballistic motion are recovered, and the trajectory is extrapolated to predict the positions of the rover for the remainder of the hop. In the second step, we devise a scheme called ¿selective vision¿, combining the ideas of active vision and guided search. An envelope lying between the start and end of a hop is defined, within which features most likely to be re-observed across a hop are detected and matched. Performing pose estimation on the these matched features allow the relative motion between a camera frame within the visual odometry step and a camera frame within the extrapolated trajectory to be estimated. The newly determined camera frame in the extrapolated trajectory can then be used to refine the parameters of the ballistic motion, and the trajectory can be re-extrapolated to predict future positions of the hopping rover. Following this scheme, it is possible to estimate the trajectory of a hopping rover undergoing continuous rotational motion with only one set of cameras without continuous tracking of terrain features.

Institute of Space and Astronautical Science (ISAS) in Japan has launched the engineering test spacecraft "HAYABUSA" on May 9, 2003 for the asteroid "ITOKAWA". HAYABUSA includes a very tiny rover named "MINERVA." MINERVA is the world-ever rover, which would move over an asteroid surface. The mission objectives of the rover are: (1) the establishment of the mobile system on the micro-gravity environment of small planetary bodies, and (2) the demonstration of fully autonomous exploration. This paper describes the design of the rover, especially focused on the two major objectives of MINERVA mission: the mobile system and the autonomous capabilities.

This paper describes the path planning method for a planetary microrover. A planetary rover is required to travel safely over a long distance for many days in unfamiliar terrains. Hence it is very important how a planetary rover processes sensory information in order to understand the environment and to make decisions. The authors have newly developed a small rover for future lunar or planetary exploration. As a new data structure for map information, an extended elevation map is introduced, which includes the effect of the size of the rover. The proposed path planning can be conducted in such a way as if the rover were a point while the size of the rover is automatically taken into account. The map obtained by sensors includes uncertainties. Thus a path planning scheme based on traversability and probability is also proposed. The validity of the proposed method is verified by computer simulations.

Under the micro-gravity environment such as on the surface of small planetary bodies (asteroids or comets), traditional wheeled rovers are not expected to move effectively due to the low friction and inevitable detachment from the surface. Therefore, the authors propose a hopping rover suitable for exploration on the surface of small bodies. This paper describes the micro-gravity experiments of a proposed hopping rover which is driven by an internal DC motor torque. The proposed rover could hop under a micro-gravity environment. Experimental results are compared with the computational simulations.

Under the micro gravity environment, such as on the surface of small planetary bodies (asteroids or comets), traditional wheeled rovers are not expected to move effectively due to the low friction and the inevitable detachment from the surface. This paper discusses the friction-based mobility around the surface of small bodies and proposes a new mobility mechanism that drives the rover by hopping. The hop angle and the velocity are analyzed by numerical simulations, which show the effectiveness of the new mobility system.