Designing a sociable humanoid robot for interdisciplinary research

This paper presents the humanoid robot BARTHOC and the smaller, but system-equal twin, BARTHOC Junior. Both robots have been developed to study human–robot interaction. The main focus of BARTHOC's design was to realize the expression and behavior of the robot to be as human-like as possible. This allows us to apply the platform to manifold research and demonstration areas. With its human-like look and mimic possibilities it differs from other platforms like ASIMO or QRIO and enables experiments even close to Mori's 'uncanny valley'. The paper describes details of the mechanical and electrical design of BARTHOC together with its PC control interface and an overview of the interaction architecture. Its humanoid appearance allows limited imitation of human behavior. The basic interaction software running on BARTHOC has been completely ported from a mobile robot except for some functionalities that could not be used due to hardware differences such as the lack of mobility. Based on these components, the robot's human-like appearance will enable us to study embodied interaction and to explore theories of human intelligence.     

Position-based impedance control of a biped humanoid robot

This paper describes position-based impedance control for biped humanoid robot locomotion. The impedance parameters of the biped leg are adjusted in real-time according to the gait phase. In order to reduce the impact/contact forces generated between the contacting foot and the ground, the damping coefficient of the impedance of the landing foot is increased largely during the first half double support phase. In the last half double support phase, the walking pattern of the leg changed by the impedance control is returned to the desired walking pattern by using a polynomial. Also, the large stiffness of the landing leg is given to increase the momentum reduced by the viscosity of the landing leg in the first half single support phase. For the stability of the biped humanoid robot, a balance control that compensates for moments generated by the biped locomotion is employed during a whole walking cycle. For the confirmation of the impedance and balance control, we have developed a life-sized humanoid robot, WABIAN-RIII, which has 43 mechanical d.o.f. Through dynamic walking experiments, the validity of the proposed controls is verified.     

Sensor system of a small biped entertainment robot

SDR-4X II is the latest prototype model of a small biped entertainment robot. It is the improved model of SDR-4X. In this paper we report on the sensing system of this robot, which is important and essential for a small biped entertainment robot which will be used in the home environment. One technology is the design of the motion sensing system, i.e. the inclination sensor system and the force sensor system which obtains the inclination of the trunk and the foot with force. Another technology is the real-world sensing system. One aspect is the touch sensing system. The robot is used in a normal home environment, so we should strongly consider the safety aspects for human. Another is the vision sensor system. The configuration and the distance image acquisition are explained. Next is the audio sensor system which obtains the sound and the voice information. The hardware system and the direction recognition are explained. These sensing systems are the key to making the biped robot walking and dynamic motion highly stable, and understanding the real-world around the robot.     

Motion capture-based wearable interaction system and its application to a humanoid robot,AMIO

In this paper, we present a wearable interaction system to enhance interaction between a human user and a humanoid robot. The wearable interaction system assists the user and enhances interaction with the robot by intuitively imitating the user motion while expressing multimodal commands to the robot and displaying multimodal sensory feedback. AMIO, the biped humanoid robot of the AIM Laboratory, was used in experiments to confirm the performance and effectiveness of the proposed system, including the overall performance of motion tracking. Through an experimental application of this system, we successfully demonstrated human and humanoid robot interactions.     

Mechanical design of the humanoid robot platform,HUBO

The Korea Advanced Institute of Science and Technology (KAIST) humanoid robot-1 (KHR-1) was developed for the purpose of researching the walking action of bipeds. KHR-1, which has no hands or head, has 21 d.o.f.: 12 d.o.f. in the legs, 1 d.o.f. in the torso and 8 d.o.f. in the arms. The second version of this humanoid robot, KHR-2 (which has 41 d.o.f.) can walk on a living-room floor; it also moves and looks like a human. The third version, KHR-3 (HUBO), has more human-like features, a greater variety of movements and a more human-friendly character. We present the mechanical design of HUBO, including the design concept, the lower-body design, the upper-body design and the actuator selection of joints. Previously we developed and published details of KHR-1 and KHR-2. The HUBO platform, which is based on KHR-2, has 41 d.o.f., stands 125 cm tall and weighs 55 kg. From a mechanical point of view, HUBO has greater mechanical stiffness and a more detailed frame design than KHR-2. The stiffness of the frame was increased, and the detailed design around the joints and link frame was either modified or fully redesigned. We initially introduced an exterior art design concept for KHR-2 and that concept was implemented in HUBO at the mechanical design stage.     

Development of soft and distributed tactile sensors and the application to a humanoid robot

This paper describes a comprehensive tactile sensor system which can cover wide areas of full-body robots. Based on design criteria which are introduced from requirements, we develop two types of tactile sensor elements. One is a multi-valued touch sensor which has multi-level pressure thresholds. It is capable of covering wide areas of robot surfaces. The other is made of soft, conductive gel, which has the advantage of compliance compared with other sheet-type tactile sensors. With these two types sensors, we develop the tactile sensor system on the full-body robot 'H4'. Details of the sensor system on the robot and some experiments using tactile information are described.     

Robo-Erectus: a low-cost autonomous humanoid soccer robot

An exoskeleton robot can replace the wearer's motion function by operating the human's body. The purpose of this study is to propose a power assist method of walking, standing up and going up stairs based on autonomous motion of the exoskeleton robot suit, HAL (Hybrid assistive Limb), and verify the effectiveness of this method by experiment. In order to realize power assist of tasks (walking, standing up and going up stairs) autonomically, we used the Phase Sequence control which generates a task by transiting some simple basic motions called Phases. A task was divided into some Phases on the basis of the task performed by a normal person. The joint moving modes were categorized into active, passive and free modes according to the characteristic of the muscle force conditions. The autonomous motions which HAL generates in each Phase were designed corresponding to one of the categorized modes. The power assist experiments were performed by using the autonomous motion with a focus on the active mode. The experimental results showed that the wearer's muscle activation levels in each Phase were significantly reduced. With this, we confirmed the effectiveness of the proposed assist method.     

Design of walking gaits for Tao-Pie-Pie,a small humanoid robot

A new way for multi-axis robot trajectory planning using a single cubic spline incorporating velocity and acceleration clipping is presented. Equations for velocity and acceleration clipping employing the cubic spline function for a single axis are derived. A robot tool-tip velocity vector magnitude clipping algorithm is proposed. Implementation for a fly-by and contour following trajectory control is discussed.     

iCub: the design and realization of an open humanoid platform for cognitive and neuroscience research

The development of robotic cognition and the advancement of understanding of human cognition form two of the current greatest challenges in robotics and neuroscience, respectively. The RobotCub project aims to develop an embodied robotic child (iCub) with the physical (height 90 cm and mass less than 23 kg) and ultimately cognitive abilities of a 2.5-year-old human child. The iCub will be a freely available open system which can be used by scientists in all cognate disciplines from developmental psychology to epigenetic robotics to enhance understanding of cognitive systems through the study of cognitive development. The iCub will be open both in software, but more importantly in all aspects of the hardware and mechanical design. In this paper the design of the mechanisms and structures forming the basic 'body' of the iCub are described. The papers considers kinematic structures dynamic design criteria, actuator specification and selection, and detailed mechanical and electronic design. The paper concludes with tests of the performance of sample joints, and comparison of these results with the design requirements and simulation projects.     

morph3: a compact-size humanoid robot system capable of acrobatic behavior

morph3 is a compact-size humanoid robot that is able to generate acrobatic motions such as somersaults and gymnastic motion. A new mechanism and control system, i. e. a real-time joint compliance control system and tactile sensing shells on its body, make acrobatic motion possible. In this paper, the design concepts and construction of morph3 are described.     

Experimental realization of dynamic walking of the biped humanoid robot KHR-2 using zero moment point feedback and inertial measurement

This paper describes a novel control algorithm for dynamic walking of biped humanoid robots. For the test platform, we developed KHR-2 (KAIST Humanoid Robot-2) according to our design philosophy. KHR-2 has many sensory devices analogous to human sensory organs which are particularly useful for biped walking control. First, for the biped walking motion, the motion control architecture is built and then an appropriate standard walking pattern is designed for the humanoid robots by observing the human walking process. Second, we define walking stages by dividing the walking cycle according to the characteristics of motions. Third, as a walking control strategy, three kinds of control schemes are established. The first scheme is a walking pattern control that modifies the walking pattern periodically based on the sensory information during each walking cycle. The second scheme is a real-time balance control using the sensory feedback. The third scheme is a predicted motion control based on a fast decision from the previous experimental data. In each control scheme, we design online controllers that are capable of maintaining the walking stability with the control objective by using force/torque sensors and an inertial sensor. Finally, we plan the application schedule of online controllers during a walking cycle according to the walking stages, accomplish the walking control algorithm and prove its effectiveness through experiments with KHR-2.     

Online tracking and mimicking of human movements by a humanoid robot

This paper describes a humanoid robot system that can capture and mimic the motion of human body parts in real-time. The underlying vision system is able to automatically detect and track human body parts such as hands and faces in images captured by the robot's eyes. It is based on a probabilistic approach that can detect and track multiple blobs in a 60-Hz stereo image stream on a standard dual processor PC. A random jerk model is employed to approximate the observed human motion and a Kalman filter is used to estimate its parameters (three-dimensional positions, velocities and accelerations). This enables the system to realistically mimic the perceived motion in real-time.     

Reinforcement learning of humanoid rhythmic walking parameters based on visual information

This paper presents a method for learning the parameters of rhythmic walking to generate purposive humanoid motions. The controller consists of the two layers: rhythmic walking is realized by the lower layer, which adjusts the speed of the phase on the desired trajectory depending on sensory information, and the upper layer learns (i) the feasible parameter sets that enable stable walking, (ii) the causal relationship between the walking parameters to be given to the lower-layer controller and the change in the sensory information and (iii) the feasible rhythmic walking parameters by reinforcement learning so that a robot can reach the goal based on visual information. The experimental results show that a real humanoid learns to reach the ball and to shoot it into the goal in the context of the RoboCup soccer competition, and the further issues are discussed.     

Dexterity and versatility in the pinching motion of robot fingers with multi-degrees of freedom

This paper focuses on dexterity and versatility in pinching a rectangular object by a pair of robot fingers based on sensory feedback. In the pinching motion of humans, it is possible to execute concurrent pinching and orientation control quickly and precisely by using only the thumb and index finger. However, it is not easy for robot fingers to perform such imposed tasks agilely and simultaneously. In the case of robotic grasping, to perform concurrently such plural tasks retards the convergence speed in the execution of the overall task. This means that in order to increase versatility by imposing additional tasks, dexterity in the execution of each task may deteriorate. In this paper it is shown that both dexterity and versatility in the execution of such imposed tasks can be enhanced remarkably, without any deterioration in dexterity in the execution of each task, by using a sensory feedback method based on the idea of role-sharing joint control which comes from observation of the functional role of each human finger joint.