We have been developing a small biped entertainment robot and expanding its capabilities for adaptability and mobility in the home environment with enhanced core technologies. Conspicuous enhancements are a new robot actuator, ISA and Real-time Integrated Adaptive Motion Control System as a comprehensive motion control for SDR to realize the dynamic and smooth/elegant motion performances. In order to evaluate the basic motion control capabilities we propose a new motion evaluating system for a small biped entertainment robot. The system is composed of the SDR Motion Base and the control system. We have developed a serial-parallel hybrid type mechanism to apply for the basic experiment of SDR's motion control capabilities. We discuss the design concept of the motion evaluating system and the experimental method using the proposed Motion Base.

This paper proposes the integrated motion control method to make a bipedal humanoid walk, jump and run. This method generates dynamically consistent motion patterns in real-time based on the concept of the dynamics filter, which assures that the force and the moment generated by the robot can equilibrate with that caused by the environment. The validity of the algorithm is verified by the dynamic simulation. The proposed method is applied to the real humanoid "QRIO" under the adaptive controls, and stable walking, jumping and running including the transitions between them are realized.

SDR-4X is the latest prototype model, which remains a small humanoid type robot and is expanding its capabilities for the adaptability in home environment. Some of the new key technologies have been developed for SDR-4X. The first is newly developed small robot actuators named ISA-4, the second is real-time integrated adaptive motion control. The third is a motion creating software system, which allows us to create SDR's attractive motion performances. The fourth technology is real-time real-world space perception, and the fifth is multi-modal human robot interaction. These five technologies enable to realize a capable robot that can be adopted with human in home environment. In addition, we have explored and developed entertainment applications using these technologies. A cappella chorus performance and a high-tempo dance performance are introduced as the attractive applications.

SDR-4X is the latest prototype model, which is a small humanoid type robot. We reported the outline of this robot last year. In this paper we discuss more about mechanical system, which is important and original for a small biped entertainment robot, which will be used, in home environment. One technology is the design of actuators alignment in the body, which enables dynamic motion performance. Another technology is the actuator technology, which we originally developed, named intelligent servo actuator (ISA). We explain the specification and the important technical points. Next technology is the sensor system, which supports the high performance of the robot, especially the detection of outside objects, ability of stable walking motion and safe interaction with human. The robot is used in normal home environment, so we should strongly consider the falling-over of the robot. We propose the ideas against falling-over which makes the robot as safe as possible.

SDR-4X is a small biped entertainment robot with expanded capabilities for a variety of motion performances. We developed the SDR motion creating system and the whole body adaptive motion control for SDR. This software system makes it easy to produce creative motion performances that include stable biped walking and dance steps synchronized to music. The motion creating system is composed of two parts: the motion editor used to edit upper body motion and whole body motion, and the foot trajectory editor used to create stable lower body motion. Once the upper and lower body motions are created, the system allows the motion designer to inspection the whole body motion before applying it to SDR-4X. The process of creating a fast-paced dance performance is introduced as an attractive application of this software system.

In this paper we propose a novel application of a humanoid robot: Motion Entertainment, i.e., entertaining people with motion performance of a small humanoid robot. We develop a prototype humanoid robot named SDR-3X, which is about 50 cm height with 26 DOF. Performing to high tempo music with fast speed whole body motion can provide a big impact to an audience. Some key technologies such as a newly developed actuator enable the realization of SDR-3X. In addition, the use of OPEN-R is another key factor for quick development. We describe the architecture and the key technologies of SDR-3X. We also describe a demonstration of Motion Entertainment by SDR-3X.

This research is aimed at the development of bipedal humanoid robots working in a human living space, with a focus on its physical construction and motion control method. At the first stage, we developed the bipedal humanoid robot WABIAN (Waseda bipedal humanoid), and proposed a control method for dynamic cooperative biped walking. In this paper, we present a follow-walking control method with a switching patterns technique for a bipedal humanoid robot to follow human motion by hand contact. By a combination of both algorithms, the robot is able to perform dynamic stepping and walking forward and backward in a continuous time while someone is pushing or pulling its hand. In this paper, the authors describe the control methods for the realization of physical interaction between a human and a bipedal humanoid robot.

The authors have focused on the bipedal humanoid robot expected to play an active role in human living space, through studies on an anthropomorphic biped walking robot. As the first stage of developing a bipedal humanoid robot, the authors developed the human-size 35 active DOF bipedal humanoid robot "WABIAN" and the human-size 41 active DOF bipedal humanoid robot "WABIAN-R". The authors also proposed a basic control method of whole body cooperative dynamic biped walking that uses trunk or trunk-waist cooperative motion to compensate for three-axis (pitch, roll and yaw-axis) moment generated not only by the motion of the lower-limbs planned arbitrarily but by the time trajectory of the hands planned arbitrarily. Using these systems and the control method, normal biped walking (forward and backward), dynamic dance, waving arms and hip, dynamic carrying of a load using its arms, and trunk-waist cooperative dynamic walking are achieved.

The authors introduce a life-size biped walking robot having antagonistic driven joints using a nonlinear spring mechanism and a dynamic biped walking control method using these joints. In the current research concerning a biped walking robot, there is no developed example of a life-size biped walking robot with antagonistically driven joints by which the human musculo-skeletal system is imitated in lower limbs. Humans are considered to walk efficiently using the inertial energy and the potential energy of the lower limbs effectively, walk smoothly with less impact force when a foot lands and cope flexibly with the outside environment. The human joint is driven by two or more muscle groups. Humans can vary the joint stiffness, using nonlinear spring characteristics possessed by the muscles themselves. These functions are indispensable for a humanoid. However, the biped walking robots developed previously have been unable to walk in this way. Therefore, the authors developed a biped walking robot having antagonistic driven joints, and proposed a walking control method for dynamic biped walking that uses antagonistic driven joints to vary joint stiffness. The authors performed walking experiments using the biped walking robot and the control method. As a result, dynamic biped walking varying the joint stiffness using antagonistic driven joints was realized.

In this paper, we introduce a trial to realize interaction between creatures and robots. As the first step, rats were selected as an experimental target as a simplified form of interaction between human and humanoid robots. A rat robot was developed. Infrared transmitter, similar outlook of rat's figure and size, front-wheel steering and rear-wheel driving mechanism were equipped to the robot as the main features of the robot. An experiment system was developed to enable interaction between the rat robot and rats. The experiment system is equipped with a color CCD camera which captures and processes images of the rat and the rat robot in real-time. Behavioral experiments were performed with the system. As a result, it was confirmed that behaviors of the rat robot influence the rat's behaviors.

The authors proposed the construction of a bipedal humanoid robot that has a head system with visual sensors, two hand-arm systems, 3-DOF trunk and antagonistic driven joints using the nonlinear spring mechanism, on the basis of WL-13. And we really designed and built it. In addition, as the first step to realize the dynamic cooperative motion of limbs and 3-DOF trunk, the authors developed the control algorithm and the simulation program that generates the trajectory of 3-DOF trunk for stable biped walking pattern even if the trajectories of upper and lower limbs are arbitrarily set for locomotion and manipulation respectively. Using this preset walking pattern with variable muscle tension references correspond to swing phase and stance phase, the authors performed walking experiment of dynamic walking forward and backward dynamic dance with 3-DOF trunk motion and carrying, on a flat level surface (1.28 s/step with a 0.15 m step length). As a result, the efficiency of our walking control algorithm and robot system was proved. In this paper, the mechanism of WABIAN and its control method are introduced.

The authors are engaged in studies of biped walking robots from the following two viewpoints. One is a viewpoint as a human science. The other is a viewpoint towards the development of humanoid robots. In the current research concerning a biped walking robot, there is no developed example of a life-size biped walking robot with the antagonistically driven joints by which the human musculo-skeletal system is imitated in lower limbs. Humans are considered to exhibit walking behavior, both efficient and capable of flexibly coping with contact with the outside environment. However, developed biped walking robots can not realize the human walking. The human joint is driven by two or more antagonistic muscle groups. Humans can vary the joint stiffness, using nonlinear spring characteristics possessed by the muscle themselves. The function is an indispensable function for a humanoid. Therefore, the authors designed and built an anthropomorphic biped walking robot having antagonistic driven joints. In this paper, the authors introduce the design method of the robot. The authors performed walking experiments with the robot. As a result, quasi-dynamic biped walking using antagonist driven joint was realized. The walking speed was 7.68 s/step with a 0.1 m step length.

The authors are engaged in studies of biped walking robots from the following two viewpoints. One is a viewpoint as a human science. The other is a viewpoint towards the development of humanoid robots. In the current research concerning a biped walking robot, there is no developed example of a life-size biped walking robot with the antagonistically driven joints by which the human musculo-skeletal system is imitated in lower limbs. Humans are considered to exhibit walking behavior, both efficient and capable of flexibly coping with contact with the outside environment. However, developed biped walking robots can not realize the human walking. Humans can vary the joint stiffness, using nonlinear spring characteristics possessed by the muscle themselves. The function is an indispensable function for a bipedal humanoid. Therefore, the authors designed and built a biped walking robot and a bipedal humanoid having antagonistic driven joints. In this paper, the authors introduce the design method of the biped walking robot. The authors performed walking experiments with the biped walking robot and the bipedal humanoid As a result, quasi-dynamic biped walking, dynamic walking, dynamic dancing with dance music and carry with dynamic walking using antagonist driven joint were realized.

In this paper, the authors introduce an anthropomorphic dynamic biped walking robot adapting to the humans' living floor. The robot has two systems: 1) a special foot system to obtain the position relative to a landing surface and the gradient of the surface during its dynamic walking; 2) an adaptive walking control system to adapt to the path surfaces with unknown shapes by utilising the information of landing surface, obtained by the foot system. Two units of the foot system WAF-3 have been developed: a biped walking robot WL-12RVII that has the foot system and the adaptive walking control system installed inside it. A walking experiment with the WL-12RVII was performed. As a result, dynamic biped walking adapting to humans' living floor with unknown shape was realised. The maximum walking speed was 1.28 s/step with a 0.3 m step length, and the adaptable deviation range was from -16 to 16 mm/step in the vertical direction, and from -3 to +3/spl deg/ in the tilt angle.

As the first stage of dynamic biped walking adapting to an unknown uneven surface using an anthropomorphic biped walking robot, this paper introduces a special foot mechanism with shock-absorbing material that stabilizes dynamic biped walking and acquires position information on the landing surface. The new foot has three functions: (1) a function to obtain information on the position relative to a landing surface; (2) a function to absorb the shock of the foot landing; and (3) a function to stabilize changes in the support leg. Two units of the foot mechanism were produced, a biped walking robot WL-12RVI that had the foot mechanism installed inside it was developed and a walking experiment with WL-12RVI was performed. As a result, decreased vibration around the pitch axis, decreased torque demands on ankle actuators on the pitch axis, increased dynamic biped walking success probability, and acquired landing surface information were achieved.

The authors have started to study on the development of a hydraulically powered quadruped walking robot having a trunk which stabilizes its walking by generating compensation moment to the ground for higher mobility on a flat floor. This paper describes a motion control method of the trunk for moment compensation and results of dynamic simulation for the walking.

In this paper, as the first stage of biped walking adapting to an uneven surface using an anthropomorphic biped walking robot, the authors introduce a biped walking control method for adapting to a surface that is called a horizontally composed (HC) plane whose step height is unknown, and a special foot mechanism which is capable of shock absorbtion. The authors developed an anthropomorphic biped walking robot with a foot mechanism and performed walking experiments with the robot using the control method. As a result, adaptive dynamic biped walking over a step of unknown height was realized. The maximum walking speed was 0.96 sec per step with a 0.3 m step length, and the greatest step height was 12 mm. The authors believe that the adaptability is integral to an anthropomorphic robot that will support human living in the near future. The authors call the robot Humanoid.>

The authors have been using the ZMP (zero moment point) as a criterion to distinguish the stability of walking for a biped walking robot which has a trunk. The authors introduce a control method of dynamic biped walking for a biped walking robot to compensate for the three-axis (pitch, roll and yaw-axis) moment on an arbitrary planned ZMP by trunk motion. The authors developed a biped walking robot and performed a walking experiment with the robot using the control method. The result was a fast dynamic biped walking at the walking speed of 0.54 s/step with a 0.3 m step on a flat floor. This walking speed is about 50% faster than that with the robot which compensates for only the two-axis (pitch and roll-axis) moment by trunk motion.