Toshimichi Tsumaki

Rocket-propelled exploration robot: Shooting scouter, concept and evaluation of flight dynamics

This paper presents the concept and evaluation of flight dynamics for the small sized rocket-propelled exploration robot, “Shooting Scouter”. Most of the planetary rovers are actuated by the wheels, causing their velocity limited by the electrical power restriction and the heat exhausting efficiency of the motors. Also the locomotion distance is strongly influenced by features of the terrain of the planetary surfaces. To realize the system capable of improving those problems, we focused on the rocket propellant and proposed the robot named Shooting Scouter. Due to the rocket propellant, Shooting Scouters locomotion is not influenced by features of the terrain. In addition, according to the launching payload capacity of the launching rocket, small-sized lightweight actuators have the advantage of a low launching cost. However, a small-sized lightweight airframe causes a higher sensitivity for the deviation of the center of gravity, resulting in loss of control and missing the target site. This paper presents the evaluation of flight dynamics of Shooting Scouter and presents technologies to land Shooting Scouter on the target site, that can be used in space environment. One of the technologies is to stabilize the attitude during the flight. We focused on the technology to stabilize the attitude of the spinning satellite. The function to spin the reaction wheel inside the airframe is integrated on the design of Shooting Scouter, while the reaction force of the wheel is employed for the post-landing locomotion. The other technology is to improve accuracy of flying direction and distance by managing the center of gravity. A simplified center of gravity measuring device is developed to calibrate the deviation. Our experimental results show these technologies achieved stabilizing attitude during the flight and reduced the landing point error of Shooting Scouter.

Development of simulation system for multi-pair crawlered and transforming explorer

This paper describes a development of simulation system to verify performance of our proposing multi-crawlered and transforming lunar and planetary explorers. Firstly, we propose a new type of explorer capable of transforming its configuration and with a multiple pair of crawler mechanisms to improve mobility in extra-rough terrain. Secondly, modeling equations for a multiple pair of crawlers connected to transformable legs are formulated. The application of the model to a conceptual examination and transforming pattern to facilitate mobility over extra-rough terrain is discussed, whereupon physical parameters for a conceptual design model are identified through experiment using developed conceptual model. Finally, the hill-climbing performance was evaluated to assess the effectivity of the proposed explorer and validate the proposed simulation method.

Distance control of rocket-propelled miniature exploration robot

A rocket-propelled miniature robot is capable to explore sites that planetary rovers cannot reach with efficiency in locomotion distance per mass. The technical difficulty is the significant variance in its flight distance because of two factors: sensitivity of error in the center of gravity with respect to the thrust axis, and solid rocket engines deviance in thrusting force. To overcome the issue, our flight distance control strategy includes flight trajectory forming, and the flight trajectory prediction including the opposing shot. With our method, we experimentally showed the flight distance to the forward direction improved by a factor of four in variance reduction.