The Application Of Control Theories To JIT Manufacture

The factories offer productions and services by using production factors to the society to meet the needs of people. The predict of a company's production capacity is very important for this offering and its own development. The output is a parameter which we can charge the production capacity by it. The output is determined by six factors which are people, machine, material, method, environment and inspection. It is useful to find out the relationship between the output and the six factors. Usually people can find the relationship between the output and one factor of the six. This method is always not so accurate because these six factors influence the output together but not single. We can see these six factors as a function's independent variable and see the output as its dependent variable. The more independent variable the function includes the more accurate the predict is. The production process is so complicated, it is influenced by so many stochastic factors, that it is difficult for people to create the function which relates the dependent variable and more than one independent variable. The greybox model using least squares method is a model which can create a function just according to the history data. We firstly create a function according to the Taylor expansion whose coefficients are unknown. Then we can exercise the history data to calculate the coefficients. We will get the function we want.The essential of the JIT is to produce the productions when they are needed and to eliminate all the waste and storage . The way to eliminate the storage is to keep every production unit's capacity and production rhythm same. When the production plan changes we can change the six factors according to the function we have created to realize the JIT. We choose three workshop section to housing machining department , rotor machining department and brake adjustment department. We create these three workshop sections'function to relate the output and the people, machine and material according to the history data by using greybox model method. We just choose the factors like people, machine and material as the function's independent variable because it is difficult to quantify method and environment. We lastly change the factors according to the functions to realize these three workshop's JIT.