Ikuo Mizuuchi

An advanced musculoskeletal humanoid Kojiro

We have been promoting a project of musculoskeletal humanoids. The project aims at the long-term goal of human-symbiotic robots as well as the mid-term goal of necessary design and control concepts for musculoskeletal robots. This paper presents the concepts and aim of the project and also shows the outline of our latest results about development of new musculoskeletal humanoid Kojiro, which is the succeeding version of our previous Kotaro.

Building Spined Muscle-Tendon Humanoid

Human can perform variety of limber whole-body motions using numerous muscles and huge number of various sensors. The human brain has all the connections to the sensors and muscles, and learn how to manage them for whole-body motions. In this research, we have aimed to build a complex body with physically massive parallel sensor-motor systems to enter the next stage for studying humanoid brain systems. It is designed to have a flexible spined torso and a whole-body with fully muscle-tendon driven systems. In this paper the design and implementation of the first model of the humanoid is described with some experiments.

Thermal control of electrical motors for high-power humanoid robots

High physical ability of humanoid robots is desired for application to nursing care. Light and powerful actuators are required to realize the high-power performance. In this paper, we propose a method to bring out maximum performance of electric motors aggressively. The technique of motor core temperature estimation and control improves the motor power performance dramatically but safely without motor burnout. We have developed high power motor driver modules for the proposed method and equipped them into our humanoid robot and prototype jumping robot. High-power performance experiments with the robots demonstrate our method.

Development of muscle-driven flexible-spine humanoids

Aiming at opening up a new stage of humanoid robotics, we have been studying on the mechanically soft structure for humanoids and have developed a full-body muscle-driven flexible-spine humanoid robots. In this paper, we discuss body structure of humanoids, describing the advantages of musculoskeletal flexible body and briefly introducing the previous works on constructing hardware and software of flexible spine robots. This paper also presents the design and development of a novel musculoskeletal humanoid named Kotaro

Design and implementation of reinforceable muscle humanoid

We propose a concept of reinforceable-muscle humanoid with hyper parallel muscle-tendon systems. By the facilitation of changing the assignment of actuators, we can easily strengthen a specific part of robot body, while changing the arrangement of actuators of current humanoid robots is quite difficult. By developing muscle units in each of which a motor and sensors are integrated, and by adopting musculo-skeletal structure, the rearrangeability of muscles has been realized. This paper describes the concept, prototype design and implementation of the reinforceable muscle humanoid, and the evaluating experiment by a musculo-skeletal humanoid is presented.

Development of a remote-brained humanoid for research on whole body action

In this paper, a second generation remote-brained humanoid robot is presented which is developed for research on whole body action. Humanoid robots are important as a platform for the integration of techniques and algorithms acquired from research on manipulators, legged robots and so on. And they have new problems such as how to acquire, memorize, select and carry out various motions which use their whole bodies efficiently. In order to do research on these problems, a good robot body, which has whole body and enough performance for walking and getting up when it falls down is necessary. At the same time, a powerful brain is necessary which can be evolved through the body. As a solution to these demands, remote-brained approach was proposed and several humanoid robots was developed. Using these robots, several researches were done. For example, a brain framework called BeNet, an action acquisition using GA and NN and so on. They were done using a simple wireless connection. Interface between robot brain and its body to concentrate on a high-level problem. However this interface limited actions the robot can do simultaneously. In this paper, this old interface is taken to the next step. New interface has multiple actuator control methods which are switched on demand, and an onbody microprocessor network which controls actuators, measures sensors and interacts with a brain. Finally a new humanoid robot is developed on this interface.

Development of bilateral wearable device “kento” for control robots using muscle actuator modules

A method of giving intelligence to control robots by human navigations is one of appropriate solution to respond to a lot of unforeseeable situations, and making movement of complicated robots in contact condition with surroundings is not easy. In this research, a bilateral wearable device using stiffness adjustable muscle actuator modules is developed in order to control robots, feel external force of robots and teach motion that contact on surroundings. For an experiment it was realized maneuvering a musculo-skeletal humanoid, it could feedback humanoids external force to manipulator and its force feedback by bilateral control leads manipulator to do safety contact motion.

Design Approach of Biologically-Inspired Musculoskeletal Humanoids

In order to realize more natural and various motions like humans, humanlike musculoskeletal tendon-driven humanoids have been studied. Especially, it is very challenging to design musculoskeletal body structure which consists of complicated bones, redundant powerful and flexible muscles, and large number of distributed sensors. In addition, it is very challenging to reveal humanlike intelligence to manage these complicated musculoskeletal body structure. This paper sums up life-sized musculoskeletal humanoids Kenta, Kotaro, Kenzoh and Kenshiro which we have developed so far, and describes key technologies to develop and control these robots.

Realization of large joint movement while standing by a musculoskeletal humanoid using its spine and legs coordinately

We are developing the novel musculoskeletal humanoid that is able to do coordinated motion with arms, legs and spine. In this research, we present how to realize largely bending/extending motion while standing using spine and hip joints of a fullbody musculoskeletal humanoid, which has a complicated body like a human, such as over 90 muscles and about 60 DOFs. And we propose how to generate coordinated motions of spine and hip joints and how to control such a complicated humanoid in order to keep standing during its motion. Furthermore, we confirmed that this robot could bend/extend its spine and hip joints coordinately while standing by some experiments.

Analysis of the 1-Joint Spring-Motor Coupling System and optimization criteria focusing on the velocity increasing effect

This paper describes analysis and design criteria of the 1-Joint Spring-Motor Coupling System (SMCS). A system including series elastic elements shows vibrational responses in the velocity space, and our concept is to use the velocity peak of the system for motions that need explosive power. By tuning parameters, we can obtain instantaneously higher velocity than without any spring. We constructed a mathematical model of a 1-Joint SMCS (including motor electrical properties) and confirmed the velocity increasing effect on SMCS by numerical analyses and real experiments. And we discovered existence of the most effective inertia balance between the motor shaft and the robot link, and proposed the optimum spring constant with consideration of the moveable range of the link. We confirmed the validity and the limitation of the criteria by the real experiments.