Shin-Ichiro Nishida

A New End-effector for On-orbit Assembly of a Large Reflector

In Earth orbit, astronomical observations are possible free from any absorption or disturbances by the Earths atmosphere. Therefore, some large space telescopes and large space radio telescopes are planned for the future. We discuss the design of a radio telescope reflector which can be assembled in orbit by a space robot arm, with its networks and connecting mechanisms suitable for robot tasks. The characteristics of the new end-effector of robot arm and their suitability for onboard assembly tasks were confirmed by testing using a prototype end-effector and a two dimensional ground test arm. The test results are also described in this paper

Motion Estimation to a Failed Satellite on Orbit using Stereo Vision and 3D Model Matching

An algorithm is developed for estimating the motion (relative attitude and relative position) of large pieces of space debris, such as failed satellites. The algorithm is designed to be used by a debris removal system which would perform various operations on space debris such as observation, investigation, capture, repair, refuel and de-orbit. During these operations, the debris removal system must control its position and attitude simultaneously. Such six degree-of-freedom control becomes more difficult if the failed satellite is changing attitude, such as by nutation. The information required as feedback signals for such a controller is relative - position, velocity, attitude and angular velocity - and these are expected to be measured or estimated from image data. The algorithm uses a combination of stereo vision and 3D model matching, applying the ICP (iterative closest point) algorithm, and uses time series of images to increase the reliability of the relative attitude and position estimates. To evaluate the algorithm, a visual simulator is prepared to simulate the on-orbit optical environment in terrestrial experiments, and the motion of a miniature satellite model is estimated using images obtained from the simulator

Development of an EVA end-effector, grapple fixtures and tools for the satellite mounted robot system

There are many tasks to be performed by space robots. However a single end-effector can not meet the individual tasks requirements. NASDA is to launch an experimental robot satellite named ETS-VII. The satellite has a 6-DOF robot-arm to handle many experimental payloads. Payloads vary in mass, shape and size. Interfaces between payloads and the end-effector are standardized using grapple fixtures. Additional tools with grapple fixtures are also developed to meet specific task requirements. This paper shows current status of the space-robots EVA end-effector and development result of the ETS-VIIs end-effector, grapple fixtures and tools.

Preliminary experiments on technologies for satellite orbital maintenance using Micro-LabSat 1

For maturation of space activities, not only developing and using space systems is important, but also performing maintenance on them in their orbital environment is necessary in order to use them efficiently. The Communications Research Laboratory (CRL) has been studying an orbital maintenance system (OMS), specifically an on-orbit satellite maintenance system. An important first step is the capability to autonomously recognize and rendezvous with a target satellite. The CRL developed a microprocessor multi-chip module to control the OMS, including its robotic system and image processing, and installed it on Micro-LabSat for a mission called Micro-OLIVe (MicroLabSat was developed by NASDA and launched in 2002 together with the environment observation technology satellite ADEOS-II). In this paper, we describe the OMS concept, our experimental system and results of the Micro-OLIVe experiments. These experiments aimed at using the microprocessor multi-chip module to control the OMS, its camera units that use conventional C-MOS digital still cameras and its software used for flexible image processing.

Terramechanics evaluation of low-pressure wheel on deformable terrain

In this paper new procedures for the measurement of mobility parameters, such as contact pressure, and an analysis of a low-pressure wheel model on deformable terrain, are presented. Because the lunar surface is covered by regolith which implies an irregular and rough terrain, the rover has difficulty in moving. Therefore a new low-pressure wheel is recommended for high mobility performance and low power consumption with a less complex mechanism. A low-pressure wheel can change its contact shape and pressure distribution to account for terrain. The presented measurement is achieved by a new measurement instrument on the wheel, and we presented analysis model is conducted through analysis of terramechanics mobility dynamics of a low-pressure wheel with normal stress. These procedures are valuable for evaluating the longitudinal velocity of the low-pressure wheel on deformable terrain.

Launching penetrator by casting manipulator system

Supposing a space mission of setting monitoring devices at suitable positions on the moon, we discuss how to apply a casting manipulation to the mission. This paper addresses a mechanism of a casting manipulator system and control method to launch a penetrator to the desired position. First, we discuss launching methods, and focus on a method by using rotation of a boom. We then propose the mechanism that keeps a posture of the penetrator equipped at the tip of the boom constant for the absolute coordinate system during its rotation. This mechanism prevents the wire which connects the penetrator and the robots base from winding the boom. Analyzing a position error of landing point caused by delay of releasing the penetrator, we propose the motion control of the boom to reduce the error. Finally, we develop the system and verify the effectiveness of the proposed method through experiment.

A robotic small satellite for space debris capture

Space debris objects are generally tumbling in orbit, and so capturing and braking them involves complicated dynamical interactions between the object, the so-called “remover” spacecraft, and its robot arm, with the possibility of strong loading occurring during the procedure. In this paper, the remover and its space debris capture strategy is described which proposes the application of joint virtual depth control to the capture robot arm. We present the results of simulations and experiments that confirm the feasibility of this technique.

A Plan for Lunar Outpost Construction by using Robots

Architecture study for Lunar exploration is carried out by space agencies. JAXA is carrying out research and development of a mobility robot (rover) aimed at the Lunar surface exploration and outpost construction. The target areas for outpost construction and lunar exploration are mainly in mountainous zones, and the moons surface is covered by regolith. Achieving a steady run on such irregular terrain is the big technical problem for rovers. A newly developed lightweight crawler mechanism is good for driving on such irregular terrain because of its low contact force with the ground. This was determined considering the mass and expected payload of the rover. This paper describes composition of the robots designed for construction of lunar outpost, and also gives the scenario for outpost construction. These lunar robot are developed based on space robot technology cultivated by development of the JEMRMS and the ETS-VII robot.

Evaluation of attitude measurement using a color marker

Color marker employed in conjunction with space robots for on-orbit assembly has been developed. The marker consists of three printed discs with different colors. When used for on-orbit assembly, markers will be attached at the proximity of the connection mechanisms of assembly segment for large space structures. The distance and attitude of the segments can be measured by the positional relationship between the color discs of the marker. From the evaluation test, it has been verified that the performance of the measuring system with the color markers can meet the requirement of the space robot arms.

Lunar surface exploration using mobile robots

A lunar exploration architecture study is being carried out by space agencies. JAXA is carrying out research and development of a mobile robot (rover) to be deployed on the lunar surface for exploration and outpost construction. The main target areas for outpost construction and lunar exploration are mountainous zones. The moon’s surface is covered by regolith. Achieving a steady traversal of such irregular terrain constitutes the major technical problem for rovers. A newly developed lightweight crawler mechanism can effectively traverse such irregular terrain because of its low contact force with the ground.This fact was determined on the basis of the mass and expected payload of the rover. This paper describes a plan for Japanese lunar surface exploration using mobile robots, and presents the results of testing and analysis needed in their development. This paper also gives an overview of the lunar exploration robot to be deployed in the SELENE follow-on mission, and the composition of its mobility, navigation, and control systems.