An Integrated Design for a CNC Machine

Author(s):  
Amro Shafik ◽  
Salah Haridy

Computer Numerical Control (CNC) is a technology that converts coded instructions and numerical data into sequential actions that describe the motion of machine axes or the behavior of an end effector. Nowadays, CNC technology has been introduced to different stages of production, such as rapid prototyping, machining and finishing processes, testing, packaging, and warehousing. The main objective of this chapter is to introduce a methodology for design and implementation of a simple and low-cost educational CNC prototype. The machine consists of three independent axes driven by stepper motors through an open-loop control system. Output pulses from the parallel port of Personal Computer (PC) are used to drive the stepper motors after processing by an interface card. A flexible, responsive, and real-time Visual C# program is developed to control the motion of the machine axes. The integrated design proposed in this chapter can provide engineers and students in academic institutions with a simple foundation to efficiently build a CNC machine based on the available resources. Moreover, the proposed prototype can be used for educational purposes, demonstrations, and future research.

Author(s):  
Salah Haridy ◽  
Zhang Wu ◽  
Amro Shafik

Computer numerical control (CNC) involves machines controlled by electronic systems designed to accept numerical data and other instructions, usually in a coded form. CNC machines are more productive than conventional equipment and consequently produce parts at less cost and higher accuracy even when the higher investment is considered. This article proposes an educational scheme for designing a CNC machine for drilling printed circuit boards (PCB) holes with small diameters. The machine consists of three-independently move-fully controlled tables. Output pulses from the personal computer (PC) parallel port are used to control the machine after processing by an interface card. A flexible, responsive and real-time visual C # program is developed to control the motion of the stepper motors. The educational scheme proposed in this article can provide engineers and students in academic institutions with a simple foundation to efficiently build a CNC machine based on the available resources.


2010 ◽  
Vol 43 ◽  
pp. 207-210 ◽  
Author(s):  
Ju Li ◽  
Hui Ping Shen ◽  
Y.X. Jiang ◽  
Jia Ming Deng ◽  
Shan Shu Liu ◽  
...  

This paper studied a novel 3-DOF hybrid robot, and invented a new hybrid structure which was composed of 2-DOF parallel structure and 1-DOF serial structure. The structure of this mechanism was simple, stiffness and positioning accuracy was high. The control system based on ARM micro-controller was a step motor open-loop control system, which features compact and low cost while the control accuracy can be guaranteed. In this paper, the body composition of the robot was described, and its inverse kinematics were derived and further simplified. Hardware and software of the motion control system was designed in detail and experimented through prototype.


2014 ◽  
Vol 602-605 ◽  
pp. 1157-1160
Author(s):  
Mei Yu ◽  
Guo Wei Liu ◽  
Bing Kong

In view of the present mining spraying manipulator operation is not flexible ,spraying effect is poor, susceptible to interference and other issues, this paper studies and realizes a kind of low cost, strong practicability of spraying manipulator control system. Using S7-200PLC and 2MA860H drive to control the 86BYG250A stepper motor open-loop control system, and the precise position control is realized. By controlling of the x-y axis mine spraying manipulator. Validate the system operation is simple, highly efficient and stable, energy conservation and environmental protection, strong anti-jamming capability, it can be widely used in all kinds of mining equipment.


Author(s):  
E. I. Umez-Eronini

Abstract A model of a conventional, manually driven machine tool slide which is retrofitted for Numerical Control by merely incorporating high-power stepping motor drives, is developed. This model includes the relatively large amount of stick-slip friction in the slideways, and backlash in the drive chain, which characterize the conventional slide. Simulation results obtained using this model highlight the peculiar dynamic behavior, at low speed positioning and contouring operations, of such large stepping motor drive systems under electronically damped open-loop control. The results also demonstrate the feasibility of this low-cost approach to the retrofitting problem, given adequate open- or closed-loop controllers, and provide useful insight into the design of such control systems.


Electronics ◽  
2018 ◽  
Vol 7 (10) ◽  
pp. 242 ◽  
Author(s):  
Stefano Ricci ◽  
Valentino Meacci

Stepper motors are employed in a wide range of consumer and industrial applications. Their use is simple: a digital device generates pulse-bursts and a direction bit towards a power driver that produces the 2-phase currents feeding the motor windings. Despite its simplicity, this open-loop approach fails if the torque load exceeds the motor capacity, so the motor and driver should be oversized at the expense of efficiency and cost. Field-Oriented closed-loop Control (FOC) solves the problem, and the recent availability of low cost electronics devices like Digital Signal Processors, Field Programmable Gate Arrays (FPGA), or even Microcontrollers with dedicated peripherals, fostered the investigation and implementation of several variants of the FOC method. In this paper, a simple and economic FOC torque control method for hybrid stepper motors is presented. The load angle is corrected accordingly to the actual shaft position through pulse-bursts and direction commands issued towards a commercial stepper driver, which manages the 2-phase winding currents. Thanks to the FPGA implementation, the control loop updates the electrical position every 50 μs only, thus allowing a load angle accuracy of −1/100 rad for a rotor velocity up to 750 rev/min, as shown in the reported experiments.


2001 ◽  
Vol 24 (3) ◽  
pp. 303-306
Author(s):  
Mandayam N. Anandaram ◽  
B.A. Kagali ◽  
S.P. Bhatnagar

AbstractWe have constructed a computer controlled telescope using a 0.36-m f/11 Celestron optical tube assembly for teaching and research applications. We have constructed a heavy duty fork-type equatorial mount fitted with precision machined 24 inch drive disks for both axes. These are friction driven by stepper motors through one inch rollers. We have used an open loop control system triggerable by an ST-4 CCD camera to acquire and track any target object. Our telescope can home in on any target within a range of two arc-minutes. We have employed a commercial stepper motor controller card for which we have written a user friendly pc based telescope control software in C. Photometry using a solid state photometer, and imaging by an ST-6 CCD camera are possible.We consider that this project is suitable for those wishing to construct some parts of a telescope and understand the principles of operation. A simpler model of this telescope could use DC motors instead of stepper motors. We shall be happy to send our design diagrams and details to those interested. This project was funded by the DST, and was assisted by IUCAA, Pune.


This paper presents design and control of dual-switch non-inverting buck-boost converter (CBB). This converter is designed to simplify the compatibility of electronic ballast with simple and low cost LED drivers. The converter provides starting voltage and current limitation of electronic ballasts, which operates at continuous conduction mode (C.C.M.). The voltage of load terminal is controlled by adjusting the duty cycle of the PWM regulator. Although both converter switches are controlled separately, one feedback control loop is needed to obtain the desired compensator level. Appropriate control requirements have been defined by analyzing open-loop characteristic of converter transfer function through the small-signal model of CBB, which lets decide about the control strategy and analyse the stability and performance of the closed loop control system. In order to obtain the desired output voltage, Type-III rational controller is preferred because of the non-minimum phase feature in the converter boost mode. The performance of the synthesized voltage controller is verified by comparing of the pre-determined performance requirements and the obtained simulation results.


2011 ◽  
Vol 418-420 ◽  
pp. 1865-1868
Author(s):  
Ming Jin Yang ◽  
Xi Wen Li ◽  
Zhi Gang Wang ◽  
Tie Lin Shi

The performance of speed regulating is very important to the mixing process with safe, efficient operation and high quality of production. Strategies and practices of responses and optimization of a PID-based speed regulating system of a planetary mixer were presented in this paper. Research results show that: by means of the signal constraint function presented by Simulink Response Optimization, optimization PID parameters of the 2-DOF-PID controller can be obtained, and the response of close-loop control system has quite good performance of overshoot, response time, and stability compared with an open-loop control system.


2016 ◽  
Vol 28 (04) ◽  
pp. 1650026
Author(s):  
K. Rouhollahi ◽  
M. Emadi Andani ◽  
S. M. Karbassi ◽  
M. Mojiri

Deep brain stimulation (DBS) is one of the most effective neurosurgical procedures to reduce Parkinsons tremor. The conventional method of DBS is open loop stimulation of one area of basal ganglia (BG). On the other hand, existing feedback causes the reduction of additional stimulatory signal delivered to the brain which results in the reduction of the side effects caused by the excessive stimulation intensity. Actually, the stimulatory intensity of the controllers is reduced proportionally by the reduction of hands tremor, which is in fact the intended rehabilitation of the disease. The meaningful objective of this study is to design an architecture of controllers to decrease three criteria. The first one is the hand’s tremor, the second one is the level of delivered stimulation signal to brain in disease condition and the third one is the ratio of the level of delivered stimulation signal in health condition to disease condition. In order to achieve these objectives, a new architecture of a closed loop control system to stimulate two areas of BG at the same time is presented. One area (STN: subthalamic nucleus) is stimulated with a state feedback (SF) controller (pole placement method) and the other area (GPi: globus pallidus internal) is stimulated with a partial state feedback controller (PSFC). Considering these criteria, the results illustrate that stimulating two areas leads to a suitable performance. Simulation results show that the PSF and SF controllers are robust enough to the variations of the system parameters. Moreover, we are able to estimate the parameters of BG model in real time; it is a valuable method to update the time variable parameters of this model.


Author(s):  
Roberto Strada ◽  
Alberto Oldani

Electro-hydraulic elevators are widely used systems, especially in low level buildings, due to their very good ratio between power generation and dynamic response. Generally, the goal of an elevator system is just to reach the floor with a precision enough to be comfortable for the passengers, without the need to follow a specific law of motion; hence an open-loop control system could be enough. Otherwise such a kind of solution reduces the number of components, bringing down the costs of production. On the other hand a complete knowledge of the mechanical system’s behaviour is required. In this work we deal with the analysis of the behaviour of a commercial hydraulic elevator driven by an open loop control that monitors the downstream pressure of the proportional valve supplying the cylinder. At the end of the paper, a closed loop solution based on the pressure measurement and on the motion time is proposed.


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