In recent years, multilayer control has been identified as the more effective control technique when compared with the centralized control discussed in Chapter 7. Application of the multilayer control brings a number of benefits, amongst which are: (1) facilitating the modular design of chassis control systems; (2) mastering complexity by masking the details of the individual subsystems at the lower layer; and (3) favoring scalability[1,2].
As described in Chapter 7, the design of the upper layer controller is crucial in the construction of the multilayer control structure. The upper layer controller determines the appropriate control commands and then distributes to the individual lower layer controllers through the coordinating control strategy. Therefore, this chapter mainly focuses on the development of the coordinating control strategy to create synergies among the different subsystems.
8.1 Multilayer Coordinating Control of Active Suspension System (ASS) and Active Front Steering (AFS)
In this section, the multilayer coordinating control of ASS and AFS is studied. It is noted that the system models developed in Chapter 7 are used in the study, including the dynamic model equipped with ASS, the road excitation model, and the tyre model. The AFS model is developed as follows.
8.1.1 AFS Model
Traditional steering systems are designed such that the ratio from the hand wheel angle to the ...