Muscle synergy is used for analysis of body movements or as input to a physical assistive device, because they can effectively express features of body movements with a smaller amount of information than the raw signals of surface EMG. Besides, if similar muscle synergy analysis can be achieved with a smaller number of myoelectric channels, it can improve the efficiency of the measurement and to reduce the computational cost. Thus, the autors have proposed a method to reduce the number of myoelectric channels in the muscle synergy analysis by selecting channels according to their magnitude of influence on the temporal patterns of muscle synergy. In this paper, first, the detailed algorithm of the proposed method to evaluate the influence of each myoelectric channel on the temporal patterns of muscle synergy and to select proper channels is presented. Second, as an example to examine the validity of the algorithm, results of muscle synergy analysis of an object lifting motion is described. Then, the presented algorithms is applied to the example to study the relationship between the number of the adopted EMG channels and the results of the revised muscle synergy analysis. Thereby, it is shown that the channel can be selected properly to the purpose.

This paper discusses a data-driven controller tuning especially from the black-box optimization perspective. In particular, this paper focuses on Bayesian optimization which estimates the function by Gaussian process regression. A new prior covariance function specialized for the controller tuning is proposed, and its effectiveness is demonstrated through a practical experiment.

This paper discusses the undershoot response of a circular path-following control for a vehicle. We adopted a method in which the rotational coordinate transformation and the time-state control form are applied to a kinematic model of the vehicle. The vehicle follows a circular path by designing an integral type servo system using the method. However, we found that an undershoot response, in which the initial output response moves in the opposite direction to the reference path, occurs under specific initial conditions. The occurrence of the initial undershoot response depends on the zero of the equivalent transfer function, which includes the effect of the zero-input response. In this study, we derive the conditions for the occurrence of the initial undershoot response based on the equivalent transfer function and show numerical simulation examples of the response.

The purpose of this paper is to design a semi-active vibration control system using a linear motion device for the fragile wooden house. The developed damping device has a simple structure that is composed a magnet-bar mover and stator coils. The device generates viscous damping force that changes in proportion to the velocity of the vibration, and it is electronically adjusted by PWM signal. It is driven with small electric power. The control system is designed based on a sliding mode control theory. To confirm the effectiveness of the system, the control experiments were carried using an experimental apparatus which composed with a wooden frame equipped with the developed semi-active damping system, and a vibratory equipment. As a result of experiments, the proposed system was able to decrease the vibration of wooden frame and to prevent the frame from collapsing. Furthermore, by applying the obtained control experimental data to the collapse simulation of a fragile wooden house, it was confirmed that the proposed system prevented the collapse of the house.

An H² preview control method is applied to Load Frequency Control (LFC) and the control performance improved by the prediction of load variation is examined based on numerical examples. The performance of the preview control is measured by the power system inertia constants, which are required for recovering the same control performances with the standard H² control. We report that the use of load demand prediction has a good effect on recovering the power system inertia constants.

This paper discusses the effect of music on reaction time as driving monotonous environment road. The major causes of rear-end collision are a decrease in concentration and alertness. To keep awake condition, some drivers are listening to music in the car. In this study, we analyze the actual accidents that occurred in Koriyama City, Fukushima prefecture, and examine the cause of rear-end collisions from the surrounding environment. On a road with a monotonous environment, the driver's concentration and arousal level decrease. Music as background music can be considered one of the methods to maintain a proper level of arousal during driving. The reaction time when listening to music is measured experimentally and compared with the reaction time when there is no music. We examine whether music is effective as a means of maintaining arousal when driving on a monotonous road.