Analysis and Design of the Stewart Platform-Based Parallel Support Bumper for Inertially Stabilized Platforms

Abstract

Stewart platform-based parallel support bumpers are widely used to prevent external shocks from damaging inertial navigation systems. Aiming at a severe problem that the inertially stabilized platform becomes out of control as soon as a specified shock is posed on the base of the bumper in shock tests, analysis, and design of the 18-leg Stewart platform-based parallel support bumper are conducted in this paper. With the help of generalized coordinate definition, a kinetic model of the parallel support bumper is established, of which inertia, stiffness, and damping matrices are derived based on kinetic energy, elastic potential energy, and damping dissipation function, respectively. The stiffness matrix is subsequently calculated in detail; intensive parameter design of the 18-leg bumpers is carried out according to the principle of stiffness equality and coupled motion reduction, and the corresponding kinetics is analyzed with Laplacian transformation. Theoretical and simulation results show that a half-sinusoidal shock with a magnitude of 25 g along a horizontal axis of the bumper base can cause rotational motion along the perpendicular horizontal axis with maximum acceleration of 2.762 × 10 <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">3</sup> °/s <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sup> , velocity of 42.3 °/s, and displacement of 3.16°, which would cause the aforementioned losing control problem if the inertially stabilized platform were not reasonably designed.