Can humans empathize with robot that displays emotional expressions? If a human can do this, how is it possible to create an emotionally interactive robot that will induce empathy from a human? As interest in emotional interactions with robots is increasing, the answers to these questions are increasingly sought by researchers in HRI. As a starting point to find these answers, three hypotheses are investigated in this paper. An experiment with ten-year old children was performed to analyze the three hypotheses. The results showed that humans can empathize with a robot when the robot expresses emotions through the use of bruise colors and speech. It was also found that the bruised color expression as used here can induce a human to empathize with a robot as much as speech expression. Additionally, no gender difference was noted when a human empathized with an emotional expressing robot.

Emotion interaction is an important issue in human robot interaction (HRI). In this paper, we focused on emotion recognition via voice. Generally emotional speech recognition used emotional speech features which are varied as emotion change. However, the emotional speech features changed by not only emotion information but also phoneme information. Therefore we should consider phoneme information when the feature is extracted. So we proposed emotional feature extraction method with considering phoneme information. At first, we evaluated several features such as pitch, energy and formant which are generally used in emotion recognition. Secondly, the features were categorized into emotion reflective features and phoneme dominant features. Finally, emotion reflective features were extracted based on same phoneme information which was classified by phoneme dominant features. This method extracted features which were more sensitive to emotion but less sensitive to phoneme.

The ability to recognize human emotion is one of the basic techniques of human-robot interaction especially on emotional interaction points of view. Hence the purpose of this paper is to describe the realization of the recognition of emotion from a voice. Especially, this paper describes a speech emotion recognition technique using eigen-FFT. In the field of speech emotion recognition, recognition rate is important not only in clean but also in noisy environments. Hence, we constructed voice noise (or babble noise) data and performed recognition tests both in clean and noisy environments using the eigen-FFT. From the experiments, we achieved accuracy of 90.1plusmn7.7% for four emotions at a 95% confidence interval and compared eigen-FFT with LPC, MFCC, and pitch in the clean environment. In the case of the noisy environments, eigen-FFT displayed superior performance over LPC, MFCC, and pitch.

This paper introduces an emotion interaction system for a service robot. The purpose of emotion interaction systems in service robots is to make people feel that the robot is not a mere machine, but reliable living assistant in the home. The emotion interaction system is composed of the emotion recognition, generation, and expression systems. A user's emotion is recognized by multi-modality, such as voice, dialogue, and touch. The robot's emotion is generated according to a psychological theory about emotion: OCC (Ortony, Clore, and Collins) model, which focuses on the user's emotional state and the information about environment and the robot itself. The generated emotion is expressed by facial expression, gesture, and the musical sound of the robot. Because the proposed system is composed of all the three components that are necessary for a full emotional interaction cycle, it can be implemented in the real robot system and be tested. Even though the multi- modality in emotion recognition and expression is still in its rudimentary stages, the proposed system is shown to be extremely useful in service robot applications. Furthermore, the proposed framework can be a cornerstone for the design of emotion interaction and generation systems for robots.

Previous researchers in the area of emotion recognition have classified emotion from the whole voice. They did not consider that emotion features vary according to the phoneme. Hence, in the present work, we study the characteristics of phonemes in emotion features. Based on the results, we define the obstruents effect, which is a negative effect resulting from increased feature values. We then recognize emotion from the voice by separating obstruents rather than from the whole voice. By separating obstruents, we could improve the emotion recognition rate by about 4.3%

When spacecraft dock with each other, impact will rise at the docking point. It is assumed in this paper that a docking platform having the shape of Stewart platform is attached at the one of the docking spacecraft to reduce the effect of impact. Although the impact between two spacecraft at the contact point of the upper plate of the platform is very large, the impact is absorbed by the docking platform and a negligible impact is transmitted to the spacecraft. To show this, the modeling of the internal impulses at the joints of multibody system is introduced and the internal impulses of the docking platform are analyzed by the modeling method.

When a robot system collides with its environment, unexpected position errors occur due to the effect of impact. Large actuation effort may grow up to compensate for these errors. The sudden increases of actuator torque may violate the torque limit. We propose to employ a redundant actuation mode to facilitate disturbance rejection. An optimal load distribution algorithm for redundantly actuated system is introduced to reduce the effect of shocks. This scheme distributes the compensating effort to the system actuators in consideration of the torque limit. The disturbance rejection capability of the proposed scheme is compared with those of other load distribution methods by simulation and experiment. A five-bar mechanism is employed as an exemplary plant.

To enhance the effective data transfer rate a multi-beam optical disk drive is presented. The beam rotating actuator is necessary for putting multi-beam on more than one track. Ray tracing is also executed for real system set-up. The beam rotating actuator is made up of a piezoelectric material, high stiffness wire hinge and dove prism. The actuator has about 1 kHz resonance frequency and a suitable operational range. The dynamic equation for the actuator is derived for the control of a real system.

When a robot system collides with environment not only the contact point but also the joints of the robot system experience impulsive forces or moments. However analysis on the so-called internal impulses acting on the joints has not attracted much attention although excessive impact may cause damage to the joint. In this work, we propose a closed-form internal impact model applicable to general classes of robotic mechanisms. The characteristics of the internal impulse are analyzed through simulation for serial-chain, closed-chain, and hybrid-chain systems. It is shown that the external impulse is distributed to the internal impulses of the various structures and that configurations best for external impulses might not be best for internal impulses.

In an optical disk system, a tracking system consists of a coarse actuator and a fine tracking actuator. The double actuality system requires many devices in order to obtain large strokes and precise displacement simultaneously. Moreover the moving parts become sophisticated because of the complicated configuration. In this paper a new one-dimensional tracking actuator combining a fine tracking actuator and a coarse actuator is designed. The voice coil motor is used as a basic drive mechanism. The permeance method is used to analyze and to design VCM for large driving forces and its characteristic is tested through experiments. The focus spring is designed in terms of the stability and characteristics of the system. Since friction is a dominant error source, friction identification is carried out. The designed actuator shows its ability to resolve a motion less than 0.1 /spl mu/m.

A multi-beam optical disc drive is a method to enhance the data transfer rate in an optical disc system by recording and reading on multi-tracks. In this paper, the beam rotating actuator needed for a multi-beam optical disc drive is developed. The voice coil motor (VCM) is used as a driving mechanism for high resolution and small size. A rotating guide based on a link structure is designed for frictionless rotation of the dove prism. The characteristics of the actuator are tested through a dynamic analyzer. It shows that the actuator has good linearity, rotating range /spl plusmn/0.34/spl deg/, minimum resolution of rotating angle 0.0066/spl deg/ and 1st natural frequency 113.9 Hz. The actuator is used for a multi-beam optical disc system.

A closed-chain mechanism having redundancy in the force domain can produce a spring effect by proper internal load distribution. The so-called antagonistic stiffness is provided by redundant actuation in conjunction with nonlinear geometric constraints. In the paper, an optimal structure of a five-bar mechanism that can maximize efficiency in generation of antagonistic stiffness is evaluated and analyzed. A stiffness modulation index that represents isotropic characteristics in antagonistic stiffness generation is proposed. A gradient design index that shows rate of change of the isotropic index is also employed to distribute the isotropy of stiffness uniformly throughout the workspace. To deal with multi-criteria based design, a composite design index based on the max-min principle of fuzzy theory is used as an objective function. Two optimization results are obtained. One is optimizing the X-directional stiffness and the other corresponds to optimizing the Y-directional stiffness. The result of the former design is found suitable for antagonistic stiffness generation as well as for first-order kinematic performances.

The latency time, which is the residual vibration of a fine actuator and track eccentricity, has been the aim for direct pull-in in optical disk systems. Modified velocity profiles of the coarse actuator and control inputs of the fine actuator have been proposed for the minimum residual vibration. Generally, there exists eccentricity due to mismatch of the disk center and the axis of a spindle motor. So, if a fine actuator is locked to the coarse actuator, another latency time must be need because of the track eccentricity. The track eccentricity can be estimated as the rotation type of the spindle motor changes from CLV to CAV. In this paper, the fine actuator is excited with the same velocity of the track and the track pull-in is executed without any latency.

This paper presents a wire parallel mechanism designed and manufactured for a robot pose measurement which can be used for a robot calibration. It consists of six parallel links using wires. The position and orientation of a robot are obtained from the wire lengths measured in the wire parallel mechanism. The complex nonlinear equations of the forward kinematics of a parallel mechanism are solved by using the numerical method (Newton-Raphson method), and the unique solution is determined from a geometric configuration of the designed mechanism. Through the experiments, it is verified that the developed mechanism can measure a full pose of a robot and has an accuracy of /spl plusmn/0.05 mm, /spl plusmn/0.1/spl deg/ in the position and orientation, respectively. In conclusion, it can be used effectively for measuring of a robot pose with low cost and effort.