Multiple input disturbance decoupling for suspension control

This paper applies multiple input disturbance decoupling (MIDD) control to vehicle suspension systems, which must deal with two input disturbances: road irregularities and load disturbances. Multi-input systems usually have multiple performance requirements and must compromise system settings to respond satisfactorily to different inputs. For instance, vehicle suspensions need low stiffness to isolate road irregularities but require high impedance to suppress load disturbances. Hence, suspension control becomes typically a trade-off between these conflicting settings. This paper introduces the MIDD control to solve these compromises. First, we introduce the input disturbance decoupling (IDD) lemma, which can adjust specified input responses while keeping others unchanged. Two sets of optimal IDD controllers are designed: one insulates road irregularities and the other represses load disturbances. The MIDD theorem can then combine these IDD controls to achieve optimal performance simultaneously while avoiding cross-influences. Finally, we conduct experiments to demonstrate the practicability and effectiveness of the MIDD control.