This paper deals with scheduling methods in a JIT production that includes lot processes. In general, the delayes often occurred in multivolume JIT production systems that include lot processes, because set-up time is increased in the multivolume JIT production. To cope with this difficulty, we propose three scheduling methods to decrease delays and work-in-process inventory in lot processes. Furthermore, we evaluated the methods by numerical experiments.
The purpose of this paper is to expand the result a of robust stability condition using phase information by Yamada. That is, recent paper can not deal with the set of the system that the number of relative degree of the nominal plant is not equal to that of the real plant. We define a class of uncertainty to include the system that the number of relative degree of the nominal plant is not equal to that of the real plant. A necessary and sufficient robust stability condition for the system with a certain class of uncertainty is presented.
A new scheduling protocol based on market mechanism in microeconomics is proposed in this paper. We define all the manufacturing units, such as machines and jobs, as economic agents, which conduct strong robustness against several manufacturing conditions. Contract-net protocol is focused in our scheduling concept due to its applicability into a scheduling problem. We study the dynamics of the proposed contract-net based scheduling protocol, and confirm its efficiency by several simulation experiments.
In this paper, we derive a method of estimating a model set for a continuous-time delay system. Using δ-operator model, we first transform the estimation problem of a continuous-time delay system to a discrete one in which the system parameters remain in their original form. Then an identification method combining the genetic algorithm (GA) with the modified ellipsoid-bounding (MEB) algorithm is developed in order to estimate the time delay and system parameters together with their bounds. Simulation results are included to show the effectiveness of the present method. Furthermore, the present technique is applied to a closed-loop identification and a robust I-PD controller design.
This paper proposes a robust control design method by imposing dissipativeness on open-loop systems. First, it is shown that stability of nominal feedback systems is equivalent to dissipativeness of open-loop systems. This result justifies imposing dissipativeness on open-loop systems. Second, a robust stability for some class of complex perturbations guaranteed by dissipativeness of open-loop systems is shown. This explains that our method is effective for ensuring gain and phase margins of feedback systems. Third, it is shown that dissipativeness of open-loop systems is equivalent to bounded realness of certain closed-loop transfer functions. This fact implies that H∞ control which evaluates only gain property possesses the ability to take into consideration both gain and phase properties of open-loop transfer functions, as well as it gives a controller design method based on dissipativeness of open-loop systems.
In this paper, we discuss a fast training method for a fuzzy classifier with ellipsoidal regions. In the calculation of the degree of membership, first we decompose the covariance matrix into triangular matrices. Then we set small offdiagonal elements relative to diagonal elements to zero, and calculate the degree of membership by skipping zero elements. We demonstrate the effectiveness of our method using several benchmark data.
Numerical running simulation of the superconducting magnetically levitated system (JR Maglev system) has been undertaken. In this system, the interaction between the propulsion and levitation system is very large. Thus, it is important to reduce the oscillation of the bogie caused by the various disturbance. The damping of the system is shown to be small. So the active damper coil system is proposed to increase the damping between the bogie and the levitation coils on the ground. The effect of the active damper coil is calculated using the running simulation program. From the calculated results, the active damper coil system shows the large effect to decrease the vertical oscillation of the bogie when the voltage in proportion to the acceleration of the vertical oscillation is applied on the damper coils.