Multi-DOF Motion Control System Design and
Realization Based on EtherCAT
Jie Ma
Control and Simulation Center
Harbin Institute of Technology
Harbin, China
majie@hit.edu.cn
Baoxiang Xing
Control and Simulation Center
Harbin Institute of Technology
Harbin, China
6110410418@hit.edu.cn
Songlin Chen
Control and Simulation Center
Harbin Institute of Technology
Harbin, China
songlin@hit.edu.cn
Abstract—EtherCAT (Ethernet for Control Automation
Technology) is gaining wide spread popularity in the automation
industry as a real time field bus based on low cost. This paper
describes design and realization for a multi degree of freedom
(Multi-DOF) motion control system including nine rotation or
rectilinear motions where EtherCAT real-time Ethernet was
selected as the communication bus. The communication model,
master and slave of EtherCAT is provided. The multi-
controller design for the single rotation motion is described in
detail. Finally, some experiment results indicates the effectiveness
and technical benefits applying the design and realization
methods in this paper.
Keywords—EtherCAT; Motion Control System; Multiple Loop;
Parameter Design
I. INTRODUCTION
With the rapid development of science technology and
social demand, industrial control systems are developing in the
direction of digitalization, intelligent and networked [1]. And
the multi degree of freedom (Multi-DOF) motion control
system is expected to have the ability of highly synchronized
actuation and below millisecond scale control periodic [2].
Typically, a cycle time less than 1 ms and a synchronization
time in micro-second level is needed. However, the traditional
Ethernet technology has been unable to meet the requirements
of the industrial control system for real-time performance and
the synchronization performance due to its non
-predictable
medium access mechanism. Besides, the classical motion
control system usually adopt the dedicated analog links for the
connection of the motion controller and the drives, and the D/A
converter is connected to the PC by ISA or PCI interface, and
its structure is shown in Fig. 1 [3]. But the motion control
system based on analog links have a series of drawbacks:
analog links are susceptible to external noise, besides, the
complex and bulky analog cabling is a g
limit for the
transmission distance and the scalability [4]. Thus, the analog
link-based motion control system is no longer proper for the
implementation of Multi-DOF motion control system [5].
In recent years, with the perfection and standardization of
the real-time Ethernet for industrial automation, and military
machinery, the motion control system based on real-time
Ethernet are gaining increasing interest, particularly, the
sed on EtherCAT [6]. EtherCAT, an open
Ethernet protocol offering very high real-time performance and
originally presented by Beckhoff, has obtained the widespread
attention recently. The EtherCAT offers many advantages over
the traditional Ethernet and the analog links. Firstly, owing to
the high transmission speed, the cycle time has been
significantly reduced. Secondly, the synchronized clock
mechanism makes it possible to design the highly synchronized
motion control system over numbers of drives. Thirdly, the low
development cost and high reliability can greatly contribute to
the competitiveness of EtherCAT.
Controller
D/A Driver Motor Load
Encoder
Signal Processing
Board
Computer
Permanent magnet
synchronous motor system
Fig. 1. Classical motion control system structure
Although the benefits of the EtherCAT-based motion
control system, however, the study in China is still in its
infancy. Reference [7] has proposed a master station scheme
based on DSP and PowerPC, but the operation ability and
storage space is limited and it is difficult to upgrade and extend
the product. Reference [8] has put forward a kind of
implementation method of the EtherCAT control system based
on STM32 processor, it takes 2 milliseconds for the EtherCAT
message from sending to receiving, which can’t satisfy the
real-time requirement of industrial motion control system. And
reference [9] and reference [10]
presented the
scheme for a uniaxial or biaxial motion control system.
In view of the problems mentioned above, this paper has
presented the implementation and analysis of the EtherCAT-
based Multi-DOF motion control system. And this paper is
organized as follows. Section II introduces the background to
the EtherCAT. Section III presents the structure of EtherCAT-
Based Multi-DOF motion control system. And in section IV,
the concrete implementation scheme of the Multi-DOF motion
control system is clarified. Section V describes the multi-loop
controller design for the single rotation motion in detail. And
finally in section VI, some experiments have been carried out
and the results have verified the effectiveness and technical
benefits applying the design and realization methods in this
paper.
This research work is partially supported by the National Natural Science
Foundation of China (Grant No. 61333001, 61427809).
2016 Sixth International Conference on Instrumentation & Measurement, Computer, Communication and Control
978-1-5090-1195-7/16 $31.00 © 2016 IEEE
DOI 10.1109/IMCCC.2016.132
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