Due to the dynamical character of electromagnetic exciter and the coupling between structure and exciter(s),the actual output force acting on the structure is usually not equal to the exact value that is supposed to be,especially when multi-exciters are used as actuators to precisely actuate large flexible structure.It is necessary to consider these effects to ensure the force generated by each exciter is the same as required.In this paper,a robust control method is proposed for the multi-input and multi-output(MIMO)structural vibration control system to trace the target actuating force of each exciter.A special signal is designed and put into the coupled mul-ti-exciter-structure system,and the input and output signals of the system are used to build a dynamic model involving both the dynamical characters of the exciters and the structure using the subspace identification method.Considering the uncertainty factors of the multi-exciter/structure system,an H-infinity robust controller is designed to decouple the coupling between structure and exciters based on the identified system model.A MIMO vibration control system combined with a flexible plate and three electromagnetic exciters is adopted to demonstrate the proposed method,both numerical simulation and model experiments showing that the output force of each exciter can trace its target force accurately within the requested frequency band. Due to the dynamical character of electromagnetic exciter and the coupling between structure and exciter (s), the actual output force acting on the structure is usually not equal to the exact value that is supposed to be, especially when multi-exciters are used as actuators to precisely actuate large flexible structure. It is necessary to consider these effects to ensure the force generated by each exciter is the same as required. In this paper, a robust control method is proposed for the multi-input and multi-output (MIMO) structural vibration control system to trace the target actuating force of each exciter. A special signal is designed and put into the coupled mul-ti-exciter-structure system, and the input and output signals of the system are used to build a dynamic model both the dynamical characters of the exciters and the structure using the subspace identification method. Consumption of the uncertainty factors of the multi-exciter / structure system, an H-infinity robust controller is designed to decouple the coupling between structure and exciters based on the identified system model. A MIMO vibration control system combined with a flexible plate and three electromagnetic exciters are adopted to demonstrate the proposed method, both numerical simulation and model experiments showing that the output force of each exciter can trace its target force accurately within the requested frequency band.