Bin Hong-zan

Nonlinear comminution process modeling based on GA–FNN in the computational comminution system

Abstract A new concept named computational comminution is firstly proposed in this paper. Based on information technology, the structure of a computational comminution system (CCS) is built. The study on CCS is very different from the traditional ones for comminution, such as the study based on theoretic models, or the study based on experimental models. As one of the key technologies in CCS, a modeling framework for comminution processes is implemented particularly by employing GA–FNN that can model complex nonlinear processes such as the comminution process of cement by integrating artificial neural networks, fuzzy sets and genetic algorithms. Application results of this modeling method to the Horomill cement comminution process show that the modeling framework discussed in this paper is efficient.

Statics of rotational 3-UPU parallel mechanisms based on principle of virtual work

Statics of rotational 3-UPU parallel mechanisms (PM) based on principle of virtual work is presented in this paper. The rotational 3-UPU PM is made up of a fixed base and a movable platform interconnected by three identical UPU type limbs, where U and P stand for universal and prismatic joint respectively, and platform can only change its orientation relative to fixed base. Given configuration of PM and force applied on platform, actuating forces in prismatic joints of each limb to keep the PM in static equilibrium can be obtained with formula put forward in this paper. To decide the actuating forces, gravity of platform and three limbs are taken into account and each limb is dissected to three parts. They are piston, cylinder and oil between the piston and the cylinder. There is difference between the actuating forces decided with the method presented in this paper and the ones calculated by using Jacobian matrix. It is thought the method presented in this paper is more accurate than that of Jacobian method. Based on formula in this paper, static simulation of the rotational 3-UPU PM used in compensating platform in deep-ocean mineral mining is worked out finally.

Workspace of Translation 3-UPU Parallel Manipulators

To determine workspace and relationship between the workspace and geometry of parallel manipulator is important for optimum design of parallel manipulators. In this paper, the workspace and the relationship between the workspace and the geometry of 3-UPU parallel manipulators with pure translation are investigated. Geometric and non-geometric constraints are denned and taken account of in determining the workspace of the translation 3-UPU manipulators. A direct average condition number is used as the global performance index of the workspace. This research shows that there exists an optimal value of the direct average condition number favorable for a good design of parallel mechanisms. The results presented in this paper are useful for the optimum design of 3-UPU parallel manipulators.

Research on Fractal-Scanning Path for Arbitrary Boundary Layer in Layered Manufacturing

The fractal curve is proposed as a novel scanning-path used in Layered Manufacturing. Aiming at a limitation that the fractal curve can only fill a square region, a method is developed to realize the trimming of fractal curve in arbitrary boundary layer by means of judging intersection points between parameterized arbitrary boundary and a FASS (space-filling, self-avoiding, simple and self-similar) fractal curve. Accordingly, the related algorithm concerning with determining intersection points has been investigated according to the recursion feature of the fractal curve, and in the process of the fractal curve traversed, the rule of judging intersection points is ascertained as well, so that the laser-scanning beam can “walk” along the fractal curve inside the desired boundary, and arbitrary contour components are fabricated.

Collaborative Design in PDM / 3D CAD Integrated Environment

Some key issues in supporting collaborative design in product data management(PDM) system and 3D computer aided design(CAD) system integrated environment are analyzed. The general architecture of the integrated environment is divided into five tiers and employs the transparently integrated mode, with the mode, function calling and information exchanging among independent PDM and CAD processes are carried out via message translation/parse approach. Product layout feature(PLF) model definition is presented, PLF model is used to represent design intention at the preliminary design phase. The collaborative design methodology employing the PLF model in PDM/3D CAD integrated environment is analyzed. The design methodology can speed up the design process, reduce the investment and improve the product quality.

Research on planar development of curved surfaces

Development of curved surface is a useful tool in CAD (computer aided design) and CAGD(computer aided geometric design). This paper presents the algorithms for developing (flattening) a smooth continuous curved surface embedded in three-dimensional space into a planar shape. First the definition of planar development of a curved surface is presented, and the distortions (at length and area) of development are discussed in this paper. Then several planar flattening methods of curved surface, and their advantages and disadvantages are analyzed in detail. For NURBS(non-uniform rational basic spline) surfaces, which are broadly used in CAGD, we put forward a new planar developing algorithm, i.e. hybrid developing, and present the steps of the algorithm. At last, some examples are used to show the effectiveness of the algorithm.

Machining complex oriented compensation system for generalized kinematic errors

This paper puts forward a machining complex oriented compensation strategy for the generalized kinematic errors (GKEs). According to this strategy, the error map, which is constructed by using the off-line measuring information of the machined work-piece, is not oriented for the machine tool but for the machining complex to compensate the GKEs. The error map is derived by the proposed predictive learning control algorithm (PLCA), which is supported by the information model of machining complex. Experimental results show that the machining complex oriented GKEs compensation strategy and the information model based PLCA is effective.