In this paper, we present the dynamics, control, and preliminary experiments on a wearable upper arm exoskeleton intended for human users with four degrees-of-freedom (dof), driven by six cables. The control of this cable-driven exoskeleton is complicated because the cables can transmit forces to the arm only under tension. The standard PD controllers or computed torque controllers perform only moderately since the cables need to be in tension. Future efforts will seek to refine these control strategies and their implementations to improve functionality of a human user.

Freely moving systems in space conserve linear and angular momentum. As moving systems collide, the velocities get altered due to transfer of momentum. The development of strategies for assembly in a free-floating work environment requires a good understanding of primitives such as self motion of the robot, propulsion of the robot due to onboard thrusters, docking of the robot, retrieval of an object from a collection of objects, and release of an object in an object pool. The analytics of such assemblies involve not only kinematics and rigid body dynamics but also collision and impact dynamics of multibody systems. This paper presents analytical models of assembly primitives and strategies for overall assembly.>

Biological systems such as human spine, elephant trunk, snakes, and earthworms possess very high maneuverability during motion. Analogous mechanical devices are useful for applications such as inspection, exploration, manipulation, and locomotion in restricted spaces. An important feature which high mobility devices possess is small motion limits at the joints. The objectives of this paper are: (i) to present an algorithm for motion planning of planar hyper-redundant manipulator systems with limited joint motion using a discrete modal summation procedure; (ii) to apply the algorithm for motion in free space as well as retrieve objects through holes in the work environment; and (iii) to show results of application of this algorithm for motion planning of a mechanical spine with many active motion segments.>