| Because of its excellent speed control performance, brushless direct current motor (BLDCM) is widely used in various fields. Recently, the motor control technology has been investigated intensively and a series of significant results have been obtained. Internet is introduced to the control system with the development. However, due to its uncertainty and randomness, many new issues emerge. The present paper aims to set up an internet-based BLDCM control system and research on some questions of networked control system (NCS).Firstly, A DSP-based BLDCM control system is designed with TMS320LF2407A as microprocessor and IR2136 as core driver. It implements precise close loop control for speed or position and provides enough protection circuit such as over-voltage, low-voltage and thermal. The control system can be connected to web server via the RS232 bus.Secondly, as time delay is one of the key technological issue in NCS, this paper analyzes the composition of the time delay, uses the ICMP protocol to test time delay. Some of its corresponding factors, such as transmission distance, period of time and digital package are analyzed as well. In order to solute those issues, this paper provides an event-timing combined model. Based on the model, an event variable parameter, independent of time and ensuring real-time regulation in terminal part, is produced.The whole control system is accomplished in the third step. It chooses the B/S communication mode, adopts holding and man-machine interactive complex control way. Distance user can access the field through the Web-Browser. In this way, the whole system can be easily operated, maintained and expanded. Different from the traditional way, this control technology conquers the limit of the space and realizes the sharing of resources and technology.Finally, some experiments on the platform are carried out, including internet real-time data acquisition, step response of speed loop based on event-timing control mode, trapezoidal graph operation, faults disposal and monitor. These experiments indicate that event-timing control mode is both effective and reliable for the issue of delay time on Internet. |
