Study On Open CNC System Architecture And Interpolation Algorithm Of Hybrid Polishing Machine Tool

As the fast developing of the manufacture, the trend of mid-small group product becomes stronger, thus a higher demand for computer numerical control machine is required. At the same time, as the developing of computer technology, software engineer technology, communication technology as well as manufacture technology, the developing of the computer numerical control system has been driven from traditional closed mode to open computer numerical control mode. The developing of computer numerical control systems has experienced the traditional developing mode, object oriented developing mode and distributing object & system developing mode. Until now, the computer numerical control system are transited and developed from traditional special close mode to universal open system both in exploitation mode and material realized mode.Much instructive research have been carried on by foreign research institution and scholar, such as OMAC plan of American, ISACA plan of Europe alliance and OSEC plan of Japan. The above three plans have explained the open computer numerical control system from different points of view. Some design theory of open computer numerical control system have also been put forward by civil scholars, such as derivative computer numerical control system which based on software chip or based on COM model and software numerical control of the lathe.The component open architecture numeral control (COANC) system has been presented based on assimilating the structure design of classical open computer numerical control system and combining with computer software/hardware technology, communication technology and control technology etc. By using software engineer technology, the integrate frame of open computer numerical control system has been built. Then, by using management pattern of software architecture pattern theory, the real-time or non real-time resource of computer numerical control system has been optimized and managed effectively. Figure 1 is COANC software architecture. The realization of computer numerical control system's function is separated from interface by applying component technology, which provided well basis for open computer numerical control system and realized loosely coupled of system.As the CORBA mid-component technology has been applied to describe the system platform, in logical this system platform is distributed but in physics it can be concentrated or distributed. The extension CCM (CORBA component model) has been applied to describe the relation among computer numerical control system component. Figure 2 is CCM assembly schematic diagram of open computer numerical control system. Each interface (such as NC program, interface between computer numerical control system and servo-system and inner interface of computer numerical control system) are compared. The interface schematic has been determined, then opening of the computer numerical control system can be realizing by interface standardization. As an example of decode component, interpolation component and communication component, this paper gives the program realizing method. By adopting component technology and COBAR mid-component technology, it achieved the goal to separate the strategy from reality and loosely couple of each component, function cohesion, as well as separate interface from reality. Along with user's requirements variation, the system can add new function or revise current function to achieve the opening requirement.Interpolation function is the key function of computer numerical control system. The dimension coordinate transformation of interpolation has been presented in this paper. This paper also compared constant feeding rate, control vector error and NURBS interpolation algorithm of material removal Rate (MRR).Thus we can draw the conclusion that by applying NURBS interpolation algorithm of MRR, the surface quality of machined work-piece can be improved, life of machine tool can be prolonged in the process of interpolating free-form surface.If the NURBS interpolation algorithm of MRR be used, the curvature of machined surface must be known. VC++ has been applied by this paper to compile deBoor algorithm which can calculate each points on the curve & one-order and two-order derivative vector, then according k =(| P′×P′|)/ (|P′|³) compute the curvature. Figure 3 is Comparison of constant feeding rate, control vector error and NURBS interpolation algorithm of material removal Rate (MRR).This paper realized the component technology based open computer numerical control system, by using Dual-DSP2812+PCI9054 multi-axis motion control card as the slave controller, the computer as the host computer, on the Parallel-series polishing machine tool hardware platform which were researched independently by our research team. Simulation experiment was done to validate the rapid and reliable system.In order to validate the rapid performance of the system, the runtime and process run-rate of profile record system which is provided by VC++ is used in this paper. The main task is to validate void PCI₉054_WriteBar2DWord (PCI₉054_HANDLE hPCI₉054,UINT addr, UINT data). The process is the special read-in function of PCI9054 data, namely, a main interface which the slave computer can receive resource in host computer. This function's response time reflect directly the dynamic characteristic of system.Figure 4 indicates that the response time of this process is 1.439ms. it can been see obviously that the system rapidity requirement has been attained.