Disturbance-Free-Payload is a novel spacecraft architecture proposed to achieve perfect vibration isolation performance of space applications. In this paper, the object under study is a DFP system in which a flexible umbilical connection between the support module (SM) and the payload module (PM) is introduced for data, power and fluid transfer. Bead model accounting for properties of mass and flexibility, is utilized to model the flexible umbilical. With incorporation of bead model, six degree-of-freedom multibody rigid-flexible dynamics for the DFP system is established via Newtonian mechanics. Along with rotational coupling between solar panels and SM, translational coupling, in particular, is taken into consideration since there is a stringent requirement on relative position between PM and SM. Based on the accurate motion equations of the DFP system, simulation studies are conducted to gain insight of the impact of umbilical connection and translational coupling on pointing performance of the DFP system. Simulation results validate effectiveness of DFP configuration in isolating vibrations transmitted from SM to PM. Besides, umbilical connection plays an important part in degrading pointing performance of PM whereas it exerts little impact on SM. Moreover, translational coupling leads to significant pointing performance degradation for both PM and SM.

A two-axis stabilizing gimbal is a device that ensures a sensor is working properly on a moving platform. When classical mechanics (Newton–Euler and Lagrange) is employed to model a two-axis stable gimbal, its limitations can complicate the modeling process. To address this issue, a method for establishing a dynamic model for a two-axis stabilizing platform based on the Kane method is proposed in this paper. The Kane method offers the advantage of a simple model structure and computational efficiency. Initially, utilizing a generalized coordinate system, expressions of the generalized velocities, deflection velocities and angular velocities are derived. Subsequently, the generalized active forces and inertial forces acting on the two-axis stabilized gimbal are analyzed. Finally, by combining force and velocity with the Kane equation, the dynamic model of the two-axis stable platform is obtained, demonstrating the validity of the Kane method for establishing the two-axis stable platform model. To ensure the pointing accuracy stability of the two-axis stabilizing platform, a Novel Particle Swarm Optimization Proportion Integration Differentiation (NPSO-PID) controller is designed using the PSO algorithm. It is then simulated in MATLAB/Simulink and compared with a classical PID controller. Simulation results demonstrate that NPSO-PID exhibits superior object tracking performance compared to classical PID controllers and better optimization of control parameters compared to traditional PSO-PID controllers.

High-precision collaborative observation is urgently needed due to the increasing demands of space science missions. Based on a conventional DFP (disturbance-free-payload) configuration, this paper presents a novel DFP that has great potential to deal with collaborative observation missions. The novel DFP system is developed, in which two or more payloads are installed via a non-contact unit and installed parallel configuration. Thus, the novel design is a multibody dynamics system. With the incorporation of the dynamics of the flexible umbilical between the PMs (payload modules) and SM (support module), the six-degrees-of-freedom multibody rigid–flexible dynamics of the whole system are derived. To verify the effectiveness of the novel DFP design in a collaborative observation mission, a multi-loop controller is designed for an inertial Earth collaborative observation mission. Simulation studies are conducted, which indicate that the proposed design can complete collaborative observation and achieve high precision.