Ryuichi Hodoshima

Quadruped walking robots at Tokyo Institute of Technology

In this article, the design principle of the leg driving mechanism to minimize energy loss and maximize output power is discussed. We will also introduce the gait control methods implemented in our previous quadruped walking robots. Finally, we will survey most of the prototype models of our quadruped walking robots.

Development of TITAN XI: a quadruped walking robot to work on slopes

There are many dangerous and time-consuming construction works performed on steep slopes. In order to improve the conditions in which these works are done, the authors propose a new construction machine that is a quadruped walking robot called TITAN XI. The main objective of remote-controlled TITAN XI system is to drill the deep holes for insertion of anchor bolts or rock bolts. In this paper, we report the system and design of TITAN XI.

HELIOS system: A team of tracked robots for special urban search and rescue operations

Fire brigades and special agencies are often demanded to operate for search and aid of human lives in extremely dangerous scenarios. It is very important to first verify the safety of the environment and to obtain remotely a clear image of the scenario inside buildings or underground spaces. Several studies have been addressing the possibility of using robotic tools to carry out safe operations.

Fundamental mechanism of dinosaur-like robot TITRUS-II utilizing coupled drive

The mechanism design and the fundamental concepts of the dinosaur-like robot called TITRUS-II are reported. It is based on practical concepts so that it can be applied in the real world. The design features include: 1) realizing high dynamic stability by using a neck and a tail as an active damper when the robot walks; 2) standing with the tail to compose a stable supporting triangle so that the robot can work stably; and 3) enabling it to do various tasks by applying a manipulator as a neck. The mechanism of the legs is also distinctive, using a coupled drive to compose four degrees of freedom.

Development of track-changeable quadruped walking robot TITAN X-design of leg driving mechanism and basic experiment-

We propose track-changeable quadruped walking robot, named “TITAN X”. TITAN X is a new leg-track hybrid mobile robot with a special leg driving system on each leg. A belt on each leg changes to a timing-belt in leg form and a track-belt in track form. TITAN X walks in leg form on rough terrain and makes tracked locomotion using track-belt on level or comparatively low-rough terrain. The characteristics of TITAN X are: 1) it has a hybrid function but is lightweight, 2) it has potential capabilities to demonstrate high-performance on highly-rough terrain. In this paper, details of leg design using a special belt are reported. Also form changing mechanisms are integrated into the system. We have constructed prototype of TITAN X to demonstrate basic performance. Experiments were conducted to verify the validity of the concept of track-changeable walking robot.

Development of a quadruped walking robot to work on steep slopes, TITAN XI (walking motion with compensation for compliance)

For large robots, the decrease in position accuracy that comes from compliance of the robot system poses significant problems. We propose a new compensation method to improve position accuracy of leg mechanisms of walking robots. With this method, compliance data that is measured manually in advance is used. At present, TITAN XI - a practical quadruped robot for use in construction - is under development, and this compensation method is being applied to its control system. In this paper, the measurement of the compliance of the leg system using a hydraulic cylinder, the bending of the legs in walking motion, and the walking motion with compensation are shown.

Development of ASURA I: Harvestman-like hexapod walking robot — Approach for long-legged robot and leg mechanism design

In this paper, a harvestman-like hexapod walking robot named ASURA I is proposed and its leg mechanism design is discussed. Modeled on a harvestman in nature, the authors have introduced the concept of mobile form that has long legs and small body to ASURA I to enhance mobile performance on rough terrain. To develop long legs relative to body, special parallel link mechanism to drive leg joints powerfully and effectively is introduced to leg mechanism of ASURA I. First, we discuss design problems of leg mechanism in detail: leg length, DOF configuration, actuator selection and leg driving system. Then, analysis of kinematics, singularity and static characteristic of leg mechanism are reported. Finally, the prototype leg, which is 1.3 m in length and 3.2 kg in weight, has been developed and tested on some basic performance. The prototype successfully have demonstrated very basic motion.

How to optimize the slope walking motion by the quadruped walking robot

Reduction of the energy consumption is one of the most important problems to utilize quadruped walking robots for various works on rugged terrain. The authors have studied basic strategy to achieve high energy efficiency when the quadruped walking robot do the motion essentially requires positive power by the analysis of body rising motion. This paper discusses the energy efficiency of the slope walking motion by the quadruped walking robot. First, we investigate the walking posture in consideration of ideal actuator characteristics where the robot consumes few negative powers at each joint which causes the main energy loss of the walking robot. Then, we investigate optimal walking posture in consideration of DC motor characteristics by the full search of three gait parameters which define the crawl gait. Furthermore, we derive the optimal walking motion by the optimization of three gait parameters which are kept constant during one cycle gait and instantaneous parameters such as body velocity and supporting forces changed at each moment simultaneously. Graphical Abstract

Improvement of the remote operability for the arm-equipped tracked vehicle HELIOS IX

This work presents the development of an arm-equipped tracked vehicle named HELIOS IX for search and rescue tasks in urban environments. HELIOS IX operator has to tele-operate several tasks such as opening of doors, negotiation of stairs and handling objects. However due to the complexity and kinematics of the system, these tasks are difficult to be carried out without some level of automation. This study proposes one of the shared autonomy type operator-supporting system for HELIOS IX. It is based on a laser range finder (LRF), finger-attached LED beam guiding systems and on a finger 3 axes force sensor interfaced by a novel reinforcing metal plate. Carrying out several experiments we could demonstrate that, tele-operation task can become easier by the introduction of the 3D space approaching assistance of the LRF, object grasping assistance of the LED beams attached on the fingers, and by the force following assistance of the force sensor attached to the wrist.

JetGun Sat “TOPPU”

In this paper, we report a conceptual design of micro-satellite for the verification of formation flying technologies. This satellite is a type of mothership-daughtership configuration called TOPPU which means a gust wind. The two satellites are connected by a tether; the mothership satellite has a docking mechanism installed, and a reel mechanism as well as gas jet gun to perform various orbital experiments. The system design of TOPPU is discussed, as is the progress of satellite system development.