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A new reactionless space robot design concept was put forward to overcome the shortcomings of the current drive types. Control moment gyros (CMGs) were mounted on each part mechanical arm and system platform as movement actuators. Mechanical arms were connected with spherical hinges. Platform attitude and angular displacement were measured by the Rodrigues parameters (RPs). Based on system dynamics model built with Kane method, a gradually stable trajectory tracking control law was designed to track the platform attitude and mechanical arm angular displacement, and a CMGs steering law was designed to output exact expected control torque. Moreover, the designed control laws can be further extended to track and control the workspace trajectory by studying the trajectory planning algorithms between the mechanical arms workspace and joints space. The simulation results from the three joints systems have verified the feasibility of design and effectiveness of the proposed trajectory algorithms. [ABSTRACT FROM AUTHOR]

The existing collision-free motion planning algorithms based on configuration space (C-Space) need to find the boundaries of C-space obstacles by solving C-space, which will cost much computation and memories for redundant manipulators with larger degrees of freedom (DOF). A novel algorithm was proposed to find the collision-free path in C-space by testing motion directions without solving @space. This algorithm contained four sul>algorithms, the collision detection algorithm, the collision-free target configuration solver, the collision-free path-searching algorithm and the path smoothing algorithm. Given the desired position and attitude of the end-effector, the target configuration solver calculated a collision-free target configuration. Then the path-searching algorithm found a collision-free path with C-space obstacle boundaries unknown. Finally, the path-smoothing algorithm smoothed the obtained path. To verify the effectiveness of the algorithm, two numerical examples were carried out. And the results indicate that the algorithm is efficient and can be used in fast motion planning for redundant manipulators in space applications. [ABSTRACT FROM AUTHOR]

A method which providing three-axis attitude control by the gimbaled thruster gimbal and yaw attitude control thruster was proposed. Firstly, the multi-body dynamics equations with the upper stage body, gimbaled thruster and gimbal support were built based on the Kane equation. The gimbaled thruster s disturbance torque and gimbal angle formulas when the gimbaled thruster working were derived. Sceondly, the upper stage attitude control law was designed based on the variable structure control law, that not only achieved 10-3 attitude control precision, but allowed the gimbaled thruster's thrust direction achieve the direction determined by the guidance system as well as was via the mass center of upper stage. Finally, the validity of the proposed method was verified by numerical simulations. [ABSTRACT FROM AUTHOR]