APPARATUS, METHOD AND PROGRAM FOR PLANNING PURCHASE AND USE OF RAW MATERIAL

PROBLEM TO BE SOLVED: To provide an apparatus for planning purchase and use of raw materials in which, even if a constraint equation and an objective function are given in a non-linear equation, it is assumed as a linear equation and formulated in a mathematical programming problem, and then can be solved.SOLUTION: An apparatus for planning purchase and use of raw materials protects constraints concerning properties of products (pig iron, sintered ore and slag) and capability of manufacturing facilities, and creates the plan for the purchase and use of the raw materials to minimize the cost relating to the purchase of the raw materials (ferrous ore, coke, coal and sub-materials) as well as manufacture. In this case, the purchase amount and usage of the coke and coal are used as a fixed value, and a constraint equation about the properties of the products and the capability of the manufacturing facilities and an objective function representing the cost are assumed as a linear equation. Also, the term that cannot be linearized is excluded from the objective function and formulated in the mathematical programming problem, and then the mathematical programming problem is optimized and a provisional optimal solution for minimizing the objective function is found. Then, this provisional optimal solution is used as an initial solution and the objective function including the non-linear term is subjected to the linear approximation in the vicinity of the initial solution, and thereby formulated in a sequential linear programming problem and applied with a sequential linear programming. 【課題】制約式及び目的関数が非線形式で与えられる場合でも、それを線形式とした数理計画問題に定式化して求解できるようにする。【解決手段】生産物（銑鉄、焼結鉱及びスラグ）の性状と製造設備の能力とに関する制約を守り、原材料（鉄鉱石、コークス、石炭及び副原料）の購買、並びに製造に掛るコストを最小化する原材料の購買及び使用計画を作成する。この場合に、コークス及び石炭の購買量及び使用量を固定値として、生産物の性状と製造設備の能力とに関する制約式、及びコストを表す目的関数を線形式とするとともに、線形化できない項を目的関数から除いて数理計画問題に定式化し、その数理計画問題を最適化して、目的関数を最小化する暫定最適解を見つける。その後、この暫定最適解を初期解として、非線形の項を含む目的関数を初期解の近傍で線形近似して、逐次線形計画問題に定式化し、逐次線形計画法を適用する。【選択図】図７