Page 290 - Distributed model predictive control for plant-wide systems

264 Distributed Model Predictive Control for Plant-Wide Systems

on the global optimization, in which every subsystem controller has to connect with other
subsystem controllers, which can result in high network load. The algorithm is complex and not
convenient for engineering applications; the article in [138] improves the existing longitudinal
multibody mass dynamic model, which optimizes the distribution of the train’s aerodynamics,
and then designs a MPC based on the global optimization. It comes across the same problem
as the article in [137]; since the N-DMPC with information constraints can lower the high
network load and high calculated load caused by the global optimization, the N-DMPC is
adopted here in the control of the high-speed train.

12.2 System Description
The movement of EMUs is a very complicated process, which is affected by different forces.
The driving of EMUs considers longitudinal movement. Influence of the longitudinal move-
ment includes traction, rolling resistance, and brake force. There are many types of EMUs
in the cavil’s train systems, such as CRH1, CRH2, CRH3, CRH5, CRH380A, CRH380B,
CRH380C, CRH380D, CRH6, and so on. The CRH2 is first used in the sixth time of improv-
ing speed of the Chinese railway systems in the year 2007 when the EMUs are first used in
Chinese dedicated passenger lines. This type has been the largest amount among the imported
other types of EMUs.
Different types of EMUs have different group organizations. In this chapter, we take the
CRH2 as our research antetype.

12.3 N-DMPC for High-Speed Trains

12.3.1 Three Types of Force
12.3.1.1 The Traction of EMUs
EMUs are driven by tractions, which are generated by the electricity of the catenary [139].
The calculation of the traction uses the method of linear interpolation by the characteristics of
tractions for the CRH2 given in Figure 12.1.
The traction is constrained by the adhesive force. When the force on the wheel rim is bigger
than the adhesive force between wheels and rails, the wheel is idling. Thus, the adhesive force
determines the upper bound of the traction.

12.3.1.2 The Resistance of EMUs
The resistance of EMUs includes two parts: basic resistance and additive resistance. The fric-
tion and concussion among components, surface and air, wheels, and rails are the main reasons
of basic resistance. The additive resistance is caused by the path.
It is difficult to analyze the resistance theoretically because the resistance of the EMUs has
a lot of parts. Generally, we find an approximate resistance formula for some EMUs from a
lot of traction experiments which can be formulated by the following equation [139]:

w = c + c v + c v 2 (12.1)
1
2
0
0