Orbit-Attitude-Rotating Coupling Dynamics of Space Manipulator Assembled with Camera

Purpose: A space manipulator assembled with a rotating camera is typically used to capture/take photos of the spacecraft’s surrondings or target being focused in space exploration and satellite services. The rotation of the camera disturbs the position and attitude of the space manipulator. The complicated orbit-attitude-rotating coupling dynamics proposes enormous challenge for dynamic modeling and vibration analysis on it. Method: In this paper, the orbit-attitude-rotating coupling dynamic behaviors of a combined structure idealized as a planar rigid rod with rotating rigid body are investigated via the structure-preserving method. Considering the coupling effects between the planal orbit-attitude motion of the rigid rod and the rotation motion of the camera, the dynamic model of the combined structure is established referring to the well-known Euler-Lagrange equation. A symplectic dimensionality reduction method is proposed to deal with the coupled equations. The energy transfer resulting from the complex coupling effects can be accurately reproduced employing the structure-preserving iteration method. Results and Conclusions: The effects of energy transfer among different mechanical components, the attitude angle and the true anomaly angle on the coupled dynamics are investigated in detail. The numerical results show that, the energy transfer, reflected by the orbit speed, the attitude angular velocity and the attitude angle value, affects the nonlinear dynamic behavior of the system remarkably. When the initial attitude angle exceeds a certain value, a second-order frequency appears in the system. However, the effect of the true anomaly angle on the system dynamics isn’t obvious. The above findings can be used to guide the attitude adjustment scheme and the vibration control strategy design for the space manipulator assembled with a component.