Design And Development Of Softeare Architecture And Major Functional For Three Dimensional Laser Cutting

Three-dimension laser cutting machine has been widely used in automobilemanufacturing industry and also plays an important role in aerospace industry. Asone of the key techniques of three-dimension laser cutting machine, NC systemlargely determines the functions and properties of machine tools. In this thesis, NCstructure based on PC and IO is employed; Linux system through hard real-timeextension by RTAI is utilized as the running platform for NC software. The softwarearchitecture of three-dimension laser cutting machine is designed and several keyfunctions are implemented. These results can improve our own research anddevelopment capabilities of three-dimension laser cutting special NC system.After function and requirement analysis of three-dimension laser cutting NCsoftware is conducted, NC tasks are classified and planned according to therequirement of real-time. Accordingly, entire structure of NC software is determinedand divided into Human-computer Interaction Module, User Function Module,Communication Module and Kernel Function Module. User Function Module runsin user space while Kernel Function Module does in kernel space, they can notcommunicate directly. FIFO and shared memory technology are used inCommunication Module to realize the communication between User FunctionModule and Kernel Function Module.On the basis of the basic numerical control functions of man-machine interface,process control and auxiliary function are developed, researched on the offset laserhead axis interpolation control algorithm, track speed smooth control function andthree-dimensional display and dynamic simulation function. Establish thecoordinate transformation model of offset laser head, Calculate the displacementsof each axises in one interpolation cycle by the synthetic point coordinates and theotary shaft angles; because of the high speed of laser cutting, to ensure thestabilization of the machine and the calm of the speed, using read-ahead method,analyse the limiting factors of speed and acceleration during the machine motion,before actual interpolation, programming the speed and acceleration of the track,confirm the motion state of each section; because of the three-dimensionalprocessing path curve is complex, and in the thesis, the three-dimensional display and dynamic simulation capabilities are developed, which is able to display themodel and the expected trajectory, and simulates the spot position and the directionof the laser beam in the real-time process, helping users to see the processing status.Verification of3D laser cutting CNC software by simulation. The real-timeperformance of CNC software depends on RTAI-Linux system platform. Themaximum response delay was tested by loading the system with simulation load.Software simulation protocol consists of verification of software structure,inter-process communications and the completion of CNC verification. CNC controlcode is read by simulation program developed in Matlab. Velocity and accelerationfor the manufacturing process are planned with the same trajectory velocitysmoothing control algorithm which applied in the Matlab program. The featuresof trajectory velocity smoothing control algorithm are verified by analyzing on thegenerated velocity and acceleration.