Research On The Fixed Length Flying Saw Control System Based On DSP

China is a country with high production and processing of pipes, of which the volume is highest in the world. However, due to outdated technology and equipment, when those enterprises cut and product pipes, the loss rate of pipes remains high. And the precision, efficiency and stability is far from satisfactory, which therefore greatly reduces profit margins. Fixed length flying saw control system, in which TMS320F28069 is the motion controller and three-phase asynchronous motor is driven by the inverter, can meet the requirements of enterprises in precision, efficiency and stability, and has a price advantage compared with the equipment of the same performance.In this paper, the fixed length flying saw control system consists of a motion controller with core of TMS320F28069 processor, servo inverter, touch screen, the saw car systems and speed measuring system. The system introduces pulse length to simplify the calculation and operation, which improves efficiency of changing instruments. When measuring the speed of each moving assembly the method of M/T weighted average transition is taken so that smooth transition of measuring rotate speed is guaranteed, and the measurement error is more stable without fluctuations, thereby enhancing the stability of the system. Speed controlling of the saw car takes different strategies at each stages:at the phase of acceleration and deceleration, speed control functions are based on the function "sin2x" and "cosx1", which can reduce the impact on controlling the motor; at the phase of synchronous adjustment phase, take double-loop PID control strategy whose inner ring takes partition of PID control strategy, to meet the higher requirements of the dynamic characteristics of the system; at the phase of zero point adjustment, take the double-loop PID control strategy. When cutting the pipe, the blade speed is adjusted in real time, and positively correlated with the contact area of blade and pipe, which can effectively reduce the incision burrs.In this paper, hardware circuit and software of fixed length flying saw control system is designed, and experimental platform to obtain the following results:operating on a touch screen interface achieves functions such as parameter setting, status monitoring, manual test, automatic operation and simulation operation; the execution of each test action is correct; the traveling length and speed measurement of movement components are accurate and stable; process of cutting pipes as the length of 2m-6m is simulated, whose fixed length accuracy is up to 3mm, the saw car speed control curve consistent with the design plan.