Abstract: By taking a foldable 6-dof parallel mechanism as an example, an approach of mechanism modelling and analysis of the ship-based stabilized platform in non-inertial system is presented. This approach can be implemented by three steps. By analysing the motions of ship and stabilized platform in inertial system, the synthesize transformation formulae of pose, velocity and acceleration of the moving platform between inertial system and non-inertial system are deduced, and the adjoin transformation matrixes are given. The mapping between input motions and generalized motions of the moving platform in non-inertial system is derived based on the influence coefficient method, and the influence coefficient matrixes in non-inertial system are built respectively. The relationship between virtual displacements of each particle of stabilized platform is given, and the coupling dynamic model of stabilized platform in non-inertial system is built by virtual work principle. The performance distributions of the stabilized platform in non-inertial system are depicted by numerical examples, and the effect of the motions in non-inertial system to the system is analysed. The method is not only available for the mechanism modelling and analysis, but also can be extended to optimization design and control of parallel stabilized platform in non-inertial system.

Key words: Adjoint transformation, Foldable mechanism, Jacobian matrices, Non-inertial system, Robotic