Design And Implementation Of Large-format Printer Paper Feeding Mechanism

Motion control is a multi-disciplinary technology associated with the development of motor control technology. Generally speaking it refers to turn the specified control flow and instruction sequences into a desired mechanical movement to achieve precise monitoring of mechanical movement, the speed adjustment and other targets in complex condition. Especially in the case of printer system multi-axis feeding paper motion control, it requires interaction between multiple paper axis linkages, smooth and reliable movement of the entire feed motion process requirement, acceleration and deceleration process is stable, as well as to meet a certain precision and speed, and ultimately to achieve efficient continuous feeding paper process. With the rapid development in recent years, the popularity of FPGA technology and related applications, FPGA programming with its simple, flexible, and gradually replace the PLC to become the core components of the motion controller. So, this paper mainly studies the design and implementation of FPGA as the main controller in printer paper feeding mechanism.This paper first introduces the FPGA and PLC respective characteristics, after in comparison to each other show that the rationality of FPGA + MCU architecture to realize the system functions. Then according to the characteristics of the feeding transmission structure, main shaft transmission ratio coefficient is deduced. And coupled with the main shaft drive subdivision number and the transmission of friction axis, finally, the system's pulse equivalent value is obtained. At the same time, the relationship between the pulse equivalent and other parameters is also described. Facilitate the framework of scalability and portability later stage. On the basis of the above, the relationship between all of the feed axis drive subdivision number with the main shaft drive subdivision number is determined. Equivalent to the establishment of a mathematical model on the existing paper feeding mechanism, blocked each feed axis different reduction ratio, different axis diameter and other mechanical differences. For the FPGA to achieve a unified multi-axis motion control feed flow laid a theoretical basis.The paper mainly introduces the design idea and control method of motor motion curve, including stepping motor drive method and common acceleration and deceleration curve, and the PWM control principle of DC motor. Combining the pulse generating principle and feed paper pulse equivalent value, the corresponding function is derived between feeding system stepper motor velocity and the module internal counter value, and draw out the speed and the count value curve based on the deduced function. So it can be more intuitive to adjust the curve segments, it is convenient that for later in the optimized feeding process fully consider compromise the stability and the time of the acceleration or deceleration. Later in order to improve the reliability of the system internal signal, propose a method to enhance the system stability from software design.According to the integrated motor characteristics and mechanical structure of the actual situation in the design process, determine the whole system function of the detailed logic tasks. The system uses top-down design approach, make the continuously print tasks as center, refine and extend functional modules gradually. Within the software architecture uses the modular design thought, MCU cooperate with upper computer and FPGA in synchronous design process, integrated into a fully functional printer paper delivery system eventually. And achieve the Modbus communication protocol in the end, making the lower computer and the upper computer communicate with each other, completing the joint commissioning of the whole machine, achieving the entire development of large format printer. The final test shows that the paper system can complete a variety of feed assignments required during printing task, and meet the design requirements.