Shinichiro Nishida

Source seeking by distributed swarm robots with sample variance control

This paper deals with a multi-source seeking problem by swarm robots. The source seeking is a task to find sources in a field, e.g., fire sites and leak places of chemicals or radiation. By using swarm robots, it is expected to find multiple sources effectively. In this paper, we design a distributed controller to appropriately spread the robots out on the multiple sources not to gather on one source. For this purpose, our proposed method adjusts the sample variance of the robots positions. Moreover, the proposed controller is distributed with which each robot only needs its local information. Therefore, the resultant swarm-robot system is leaderless, where the robots can continue their task even if some of the robots are broken down. Finally, the effectiveness of the proposed method is illustrated by simulations.

Soft landing of capsule by casting manipulator system.

This paper presents a high-speed transportation of capsule by launch. One of the main issues for the transportation is how to decelerate the capsule during its flight to avoid a large landing impact. In order to stop the capsule temporally in the air just before its landing, we propose a flight control method by multidirectional tension of wires. Since the capsule is connected with both auxiliary weights and reel system via wires, it can be geometrically constrained not to move by multiple pull of the wires. We develop the motion planner which makes the capsule reach the target at the desired speed, and control algorithm for it. The proposed method is applied to the soft landing of the capsule. The effectiveness of the proposed method is verified through the experiment.

Frequency-band and electrode-channel selection for motion discrimination from electroencephalography using ℓ 1 — constrained least squares

Many of the brain-machine interfaces (BMIs), which detect the motor imagery or the movement states by noninvasive method, use the event related desynchronization (ERD) phenomena. The ERD is known as the intensity change of the specific frequency bands such as mu, beta, theta, and gamma. However, these bands can not be strictly defined because they are slightly different from each user. In this study, we use a 1i-constrained least squares learning to obtain the coefficients of the discriminator which specialize frequency-bands and electrode-positions in each user. This parameter of the discriminator is sparse and it employs only few efficient features for discrimination. Experiment results show that the proposed method can obtain higher performance than the existing method.

Study of a new type of UAV with vertical fins

Use of a rotor type UAV that can perform three-dimensional movement and hover is being actively pursued. Although a multi-rotor type UAV is important, because it is driven by electric motors its application has the limitation of a short cruising time. In this study, the composition and control system of a single rotor UAV that achieves attitude control by pivotable vertical fins are proposed. Herein, the results of the dynamical simulations and experiments using a bread board model of the proposed UAV are described.

Modeling and analysis of tether-based mobile robot based on flight experiments

This paper discusses the dynamics of a tether-based mobile robot in space. The tether-based mobile robot is constrained geometrically using several tethers and can move within an area bounded by the tethers anchors by changing the tethers lengths. This robot is equipped with an extendable and retractable arm that approaches the tethers anchor and reposition it to another point for changing the accessible area and covering a wider area. The Japan Aerospace Exploration Agency conducted an experiment called Robot Experiment on Japanese Experimental Module (REX-J) on the International Space Station for demonstrating such a systems fundamental capabilities. In this paper, the flexibilities of the extendable arm and tethers used in the REX-J are evaluated through image analysis of flight data. This analysis provides the robots dynamics in three dimensions, which can not be verified experimentally on the ground. In addition, we propose dynamic models for the extendable arm and the tethers. The proposed models are validated by comparing the flight data and the simulation results obtained using the proposed model.

Visual measurement for on-orbit assembly of a large space antenna

In Earth orbit, solar power generation is possible free from any absorption or disturbances by the Earths atmosphere. Therefore, space solar power station is planned for the future. We discuss the assembly work of a large antenna reflector by a robot arm. For the assembly work, positioning of the arm using visual servo to colored markers is proposed. The characteristics of the new image processing method of colored marker were confirmed by testing using a ground test-bed with a positioning table. The test results are also described in this paper.

J192011 Traversal Experiments on rough terrain for "TrackWalker II" : in Mihara-Yama and Nakatajima dune

To explore in extreme environments, such as a lunar surface or volcanic area in the earth, our research group has been developing small-sized tracked robots, called “TrackWalker” and “TrackWalker II”, in a joint research project with JAXA. Each robot mounts two side sub-tracks, and each sub-track has a swing mechanism to enable simple legged locomotion for traversal on a weak a soil. From 2010 to 2011, we have conducted some field tests using the tracked robots and improved its weakness, and executed performance assessments. In 13 th , March, 2012, JAXA organized a debrief session combined with field test in Nakatajima dune, in Hamamatsu, and we performed hill-climbing demonstration. In this paper, we introduce a brief of mechanism of TrackWalker-II, and report some field tests, including Nakatajima experiment.