In this study, we evaluated a phototaxis of pillbugs(Armadillidium vulgare) by using a behavior measurement system consisting of an omnidirectional motion compensation mechanism and a cylin-drical LED display. At the first, to validate the phototaxis of pillbugs against unidirectional light stimulation, we conducted an experiment under continuous light stimulation from one direction for 30 minutes. Subsequently, to evaluate phototaxis performance under the condition that the direction of light stimulus changes alternately, we experimented under three iteration cycles conditions (160 s, 40 s, 10 s). Our results revealed that the pillbugs moved significantly in the direction of weak light intensity, and it suggested that the pillbugs has negative phototaxis. Moreover, we showed that the negative phototaxis became the strongest when the iteration cycle is 160 s, and the negative phototaxis tended to weaken as the iteration cycle became shorter. Also, when the iteration cycle is 10 s, an increase in residence time is found, suggesting that does not necessarily take the routine response behavior according to the situation.
The simulation results of the heat medium control and management of A-CAES plant (Adiabatic Compressed Air Energy Storage) are presented. For the study, the dynamic model of the A-CAES plant with liquid heat medium as heat storage is constructed in order to analyze charge-discharge cycle efficiency dependency on actual operating conditions. Various heat management systems for a CAES are proposed. Among the systems, heat medium circulating system is the most feasible solution. The heat management and storage is very important for the A-CAES plant, because about half of the energy is recovered through heat insulation and heat management. Dynamic plant efficiency analysis is also crucial because the dynamic properties of the plant influences on the efficiency. The model consists of the heat exchangers, the heat storages, the air storage and an ideal compressor and expander models. The heat transfer characteristics of the heat exchanger are tested by the experimental setup because the heat exchanger performance is the most important factor for the system efficiency. The plant scale and the heat loss influence on the charge-discharge efficiencies are shown through the simulations.
This paper proposes, for two-inertia system of low stiffness and high inertia ratio, a design method of a proportional controller that minimizes the closed-loop H∞ norm from the disturbance torque applied to the driven-side inertia to the driven-side angular velocity. The controller is to generate the driving-side torque by using the driving- and driven-side angular velocities, and is composed of two proportional coefficients configured by a simple calculation law which explicitly depends on the physical parameters. The method is based on the fact that the optimal H∞ controller is analytically derived for the case with infinite inertia ratio, and the controller for finite-inertia-ratio case is similarly given along with the derivation process by introducing an approximation due to high inertia ratio. Numerical examples show that the degradation in H∞ norm from the optimal solution is less than 0.02 dB for high inertia ratio of 10 or more. Control experiments show the validity of the proposed method.
A new algorithm is proposed to estimate parameters of Single-Input Single-Output system with colored output noise using eigenvector method. The algorithm is an expansion of the previously proposed algorithms proposed by the author with iterative estimation of the variances of noises. The newly proposed algorithm uses an iterative calculation and it consists of two parts. One part is the estimation of the system parameters using the variances and autocovariances of output noises. And it is assumed that the input noises are white Gausian noise with very small variances. The estimation of the system parameters is one of the least squares identification algorithms using eigenvector. The other part is the estimation of the variance and autocovariace of output noises using the estimated system parameters. Some simulations show the effectiveness of the proposed method.