Dynamic pointing and tracking accuracy are the most relevant indicators of dynamic performance for satellite antenna driving mechanism. Multi-clearance coupling in joints will incur high-frequency vibration errors system. Joints existing analytical models generally oversimplified as planar revolute hinges, which ignore effect multi-clearance. It cannot proficiently predict behavior mechanism wi...

The singularities for a class of kinematically simple 7-jointed revolute manipulators are found. Within the class, unnecessary lengths and 4-jointed spherical groups of joints are avoided, and successive joints are perpendicular or parallel. Four different joint layouts are required to complete this class. The concept of screw reciprocity is used to find the singular (velocity-degenerate) confi...

This paper studies the geometric design of spatial two degrees of freedom, open loop robot manipulators with revolute joints that perform tasks, which require the positioning of the end-effector in three spatial locations. This research is important in situations where a robotic manipulator or mechanism with a small number of joint degrees of freedom is designed to perform higher degree of free...

In this paper an attempt has been made to design a three legged vertical robot. Each leg of the robot is considered to have two links connected each other and with the trunk by revolute joint. The legs are symmetrically distributed over the trunk body. Movement of the Center of Gravity (CG) of the robot has been ensured considering one leg is moving at a time and other two are providing necessa...

In this paper we propose a simple model for the coupling behavior of the human spine that is capable of exhibiting anatomically correct motions of the vertebrae in virtual mannequins. Such a model transparently integrates in our inverse kinematics framework as it couples standard swing and revolute joint models. The adjustment of the joints due to the coupling is made with several simple (in)eq...

This paper examines joint coupling in underactuated robotic grippers for unstructured environments where object properties and location may not be well known. A simplified grasper consisting of a pair of two-link planar fingers with compliant revolute joints was simulated as it was actuated after contact with a target object. The joint coupling configuration of the gripper was varied in order t...

This paper studies motion planning from one zero-velocity state to another for a three-joint robot in a horizontal plane with a passive revolute third joint. Such a robot is small-time locally controllable on an open subset of its zero-velocity section, allowing it to follow any path in this subset arbitrarily closely. However, some paths are “preferred” by the dynamics of the manipulator in th...

To meet the special requirements of third mirror adjustment system for an optical telescope, a 6-P-RR-R-RR parallel platform using offset RR-joints is designed with high precision, large load-to-size ratio and stiffness. In order to improve accuracy stiffness whole mechanism, each rotating joint in subchain as zero-gap bead shaft system. When compared traditional Hooke joint, RR has certain cha...

Recursive matrix relations for kinematics and dynamics of a spatial three-degrees-of-freedom 3-RPS parallel mechanism are established in this paper. Three identical legs connect the moving platform by revolute joints. Knowing the motion of the platform, we develop first the inverse kinematical problem and determine the positions, velocities and accelerations of the robot. Further, the inverse d...