Wyniki wyszukiwania - BazTech

1

Introduction of serial architecture for small CNC facilities

Mahdavineja R. A.

Journal of Achievements in Materials and Manufacturing Engineering

|

2009

|

Vol. 36, nr 1

57-64

EN

Purpose: The concept of open-architecture control, which has been used as a main method of control in many branches such as automatic systems of machining, robotics, testing and control, causes a great increment in efficiency and precision of control systems and dynamic capability to industrial control networks. Design/methodology/approach: The high execution costs in one hand and unnecessary usage of all OAC standard components on the other hand, makes the modeling of OAC concept impossible for such systems. Findings: This paper tries to represent a simple system based on elimination of unessential elements of open-architecture to reach a limited and efficient control system. Research limitations/implications: In hierarchical architecture systems, regarding to the synchronous processes of calculation and controlling, the total execution time is very low in comparison with similar serial system. In spite of this, the execution time of synchronous processes in serial architecture is lower than hierarchical one. Practical implications: The utilization of one processor instead of multiple one, merging the industrial control network layer into system management layer and omission of processor execution layer in each axis and optimized using of multi-tasking capability of processor. Originality/value: The analysis of simulated data in motions with higher degrees of freedom shows that the usage of CNC machines with serial architecture for higher than 3-degrees of freedom is unaccepted due to large increment in total machining time.

2

Heat loss optimisation in CNC motors

Mahdavinejad R.

Archives of Materials Science and Engineering

|

2009

|

Vol. 35, nr 1

47-53

EN

Purpose: Heat loss plays very important role in CNC systems, especially in suspension systems with permanent load that are usually used for testing, detection and automatic cutting, the adjusting of motor torque in each axis is based on starting by maximum current required to overcome against resistant torque on the motion surface of the system. Design/methodology/approach: In this research a new control method is introduced for the minimization of heat loss in CNC motors. In these systems the misdirected current that causes magnetic misalignment and reduces the torque is converted to heat in the motor winding, thus reducing the motor continuous torque capability. Findings: This method is based on an open-architecture of a dynamic control to optimize the input current in order to dissipate the minimal heat loss. So that, it reaches the requested velocity-position condition with the lowest amount of misaligned magnetic field and current converted to heat. Research limitations/implications: The dynamic performance implications are more important than the steady-state torque disadvantage. Practical implications: An algorithm for the dynamic torque control is given and a simulation is carried out using this algorithm for a two axis CNC cutting system with two-guider bars suspension. Reaching to the actual requested motor current is practical implication. From this point of view, the enhanced free running of pulse width modulated (PWM) is represented. Originality/value: Results obtained in this work show that using the proposed procedure the heat loss is minimized while the speed errors are reduced and the surface finish is improved. Finally, the results of this dynamic control method is represented on CNC two axes cutting machine and extended the results on the other systems.

3

Minimization of heat loss in CNC motors via a dynamic control method

Mahdavinejad R. A.

Journal of Achievements in Materials and Manufacturing Engineering

|

2006

|

Vol. 14, nr 1-2

163--170

EN

Purpose: The aim of this paper is to optimize the input current so that it reaches the requested velocity-position condition with the lowest amount of misaligned magnetic field and current converted to heat. Design/methodology/approach: A new control method based on open architecture is introduced. Then the enhanced free running of pulse width modulated (PWM) driver is represented. Findings: The actual requested motor current is reached. Practical implications: The result of this dynamic control method is represented on CNC two axes cutting machine and extended to the other systems. Originality/value: 1. Execution simple and powerful algorithms with sufficient accuracy and speed and also manufacturing a sample one. 2. The current is being controlled by data output of positioning sensors. 3. Regarding to database updating of resistance force versus to the distance of each axis, it is possible to define a periodic control method to determine resistance forces of suspension CNC systems. 4. Reduction in speed error and also increasing in machined surface quality via analysis of linear speed’s error in a system of two axes which are executed by free-running PWM driver circuit with constant and variable reference voltages. 5. Increasing in working efficiency, decreasing in energy loss and long lasting of motor drives.