Naohiko Hanajima

A motion rule for human-friendly robots based on electrodermal activity investigations and its application to mobile robot

This paper investigates impressions on the robot motion based on EDA experiments, deduces a motion rule for human-friendly robots from the investigations, and applies it to a mobile robot experimental apparatus. In our previous work, it was suggested that actuation noise come from the robots tended to raise the sympathetic nerve system (SNS) response of the heart rate variability. In another experiment it is observed that blocking out either the sound or the sight attenuated the electrodermal activity (EDA), which reflects the SNS, to the robot motion. In the present work, the experiment was designed not so as to avoid the influence of the habituation differently from the previous experiments, which was the significant factor contributing to reducing the EDA responses. As a result of statistical analysis, it was concluded that the present work supported the result of the previous work. Based on these investigations, we deduced the motion rule for human-friendly robots from this investigation, that robots must reduce their motion speed in the immediate vicinity of humans. We constructed the experimental setup that a mobile robot approached human with its speed decreased in conformity with the rule. To estimate the distance from the human, the skin color detection and depth-from-focus techniques were applied to a monocular color video camera system with pan/tilt/zoom operation. The experimental result showed that a proper choice of commands could perform the robot motion to reduce its speed in the immediate vicinity of the human.

Influence of auditory and visual modalities on skin potential response to robot motions

This paper addresses the issue of investigating the relationship between skin potential response (SPR) and robot motion from the aspect of auditory and visual modalities. The motion of the robotic devices primarily gave stimulus to the human through the auditory and visual modalities. Our previous work indicated that actuation noise caused from the robots tended to raise the sympathetic nerve system response of the heart rate variability. However, it was difficult to evaluate instantaneous response corresponding to a specific stimulus using the HRV. The SPR is possible to reflect the instantaneous response to the stimulus. In the experiment, we controlled the conditions of the visual and/or auditory modalities by blocking out the sound and sight from the robot, a manipulator with 5 D.O.F. We also changed the position of the robot around subjects for stimuli variety. As the result, it is shown that the SPR magnitudes, under the condition of blocking out not only the sound but also the sight from the robot, tended to be significantly lower than without blocking.

Path-generating regulator along a straight passage for two-wheeled mobile robots

In this paper, the path-generating regulator is extended to tracking problem along a straight passage for two-wheeled mobile robots. As most of mobile robots are with nonholonomic constraints, it is difficult for us to make them converge to the target state with a control law. To solve this problem, many methods have been proposed. One of them is Path-generating Regulator(PGR) which designs a nonlinear regulator carrying out asymptotic convergence to a given trajectory family. However, the original method is not well suited for passages. In this paper, we will present the extended PGR for the tracking problem along a straight passage. Numerical simulations and experiments are also performed to show the effectiveness of this method.

Application and performance evaluation of a lifting device with alternating rotation hoist

There exist vertical long ropes that need periodical inspection for infrastructure maintenance. Development of lifting devices along with the ropes is demanded for steady observation at human-unreachable positions. The lifting device based on alternating rotation hoist has been proposed for carrying inspection devices to the target level. This research realizes an automatic movement of the lifting device by computer control for the improvement of speed and accuracy. Furthermore, a new frame which is equipped with the inspection device is developed for saving weight and keeping balance. Through experiments, performances of the new frame and control system are evaluated from the aspects of speed, accuracy, weight and balance. The results show that the newly developed frame has advantages in weight and speed. The inclination of frame and ascender is measured. The error values are calculated to analyze the accuracy. And the developed control system can control frame effectively.

Evaluation of whole circumference image acquisition system for a long cylindrical structures inspection robot

In an inspection of aging infrastructures has become a problem. Vertical long cylindrical structures is one of inspection targets. Therefore, we have been developing an inspection robot system for these structures. In order to inspect a surface condition of these structures, whole circumference images need to be acquired. In this peper, we implemented a whole circumference image acquisition system for an inspection of these structures in the inspection robot. This system is based on proposed multi-view imaging theory using two cameras and three mirrors. We also evaluated whole the circumference images which is obtained by the developed system using a monochrome pattern.

Exercise classification using CNN with image frames produced from time-series motion data

Exercise support systems for the elderly have been developed and some were equipped with a motion sensor to evaluate their exercise motion. Normally, it provides three-dimensional time-series data of over 20 joints. In this study, we propose to apply Convolutional Neural Network (CNN) methodology to the motion evaluation. The method converts the motion data of one exercise interval into one gray scale image. From simulation results, the CNN was possible to classify the images into specified motions.

An Improved Path-Generating Regulator for Two-Wheeled Robots to Track the Circle/Arc Passage

The improved path-generating regulator (PGR) is proposed to path track the circle/arc passage for two-wheeled robots. The PGR, which is a control method for robots so as to orient its heading toward the tangential direction of one of the curves belonging to the family of path functions, is applied to navigation problem originally. Driving environments for robots are usually roads, streets, paths, passages, and ridges. These tracks can be seen as they consist of straight lines and arcs. In the case of small interval, arc can be regarded as straight line approximately; therefore we extended the PGR to drive the robot move along circle/arc passage based on the theory that PGR to track the straight passage. In addition, the adjustable look-ahead method is proposed to improve the robot trajectory convergence property to the target circle/arc. The effectiveness is proved through MATLAB simulations on both the comparisons with the PGR and the improved PGR with adjustable look-ahead method. The results of numerical simulations show that the adjustable look-ahead method has better convergence property and stronger capacity of resisting disturbance.

Further Experiments to Investigate the Influence of Robot Motions on Human Impressions

This paper investigates human impressions of the robots reaching motion based on psychophysiological experiments. There has been an increasing development of robots that move in the immediate vicinity of humans. It is important to ensure the security and relief of humans in the presence of robots. In our previous works, we employed heart rate variabilities, skin potential responses, and skin conductance responses (SCR) to investigate the influence of robot motion on human impressions. The results of several experiments showed that there was a modality effect, that is, the blocking out of the actuation noise and sight coming from robots tended to decrease the sympathetic nerve system (SNS) response. In this paper, we performed further experiments to investigate the modality effect and the long-term effect on human impressions based on SCR analysis and subjective ratings. The long-term effect implied a variation of response to robot motion over a long period. When the same stimuli are presented to humans, their responses to the stimuli tend to attenuate gradually. This phenomenon is known as habituation. In our experimentation (Hanajima et al., 2005), the subjects were asked to engage in two successive sets of the experiment for two months. We found two kinds of habituation in the data, the variation in a day and the variation between days. We defined the short-term variation as the former and the long-term variation as the latter. By comparing them, the long-term effect was investigated. As a result, we confirmed the same modality effect as illustrated in previous works. We also observed significant differences in the short-term and long-term variation from the SCR analysis. In the analysis of subjective ratings, the significant difference in the long-term variation was observed in more subjects than in the short-term variation. This suggested that the negative mental impression of the subjects to robot motion decreased as time passed