Mechanism State Matrices for Spatial Reconfigurable Mechanisms

This paper improves augmented mechanism state matrices by replacing joint code with screw system notation. The proposed substitution allows for a more specific description of the joints in the mechanism and the capability to describe both spatial and planar mechanisms. Examples are provided which elucidate the proposed approach

A Novel Approach to the Part Orientation Problem for Robotic Assembly Applications

SCARA (Selective Compliant Assembly Robot Arm) type robots are the most common type of assembly robots. These robots have four degrees of freedom (three rotational and one translational). Typically these robots are used for assembly tasks that take place along a vertical axis. Many times, however, assembly tasks take place along a non-vertical axis. To account for non- vertical axis assembly, parts must be fed in a proper orientation to allow for correct assembly. Parts feeders and specialized end-effectors are typically used to feed parts in their proper orientation. This thesis investigates a novel end-effector that can be used to feed parts for industrial assembly applications. Specifically, the purpose of the novel end-effector is to provide a SCARA robot with an added selectable degree of freedom. This end-effector aims to bridge the gap between complex anthropomorphic grippers and simple binary grippers. The approach is novel in that the end-effector interacts with the environment to produce the added degree of freedom. New path planning algorithms were developed to work in conjunction with the novel end-effector. A prototype end-effector was designed, built, and tested to prove the validity of this new approach

Profile Synthesis Of Planar Variable Joints

Reconfigurable mechanisms provide quick changeover and reduced costs for low volume manufacturing applications. In addition, these mechanisms provide added flexibility in the context of a constrained environment. A subset of planar reconfigurable mechanisms use variable joints to provide this added adaptability. In this dissertation, the profile synthesis of planar variable joints that change from a rotational motion to a translational motion was investigated. A method was developed to perform automated profile synthesis. It was shown that combinations of higher variable joints can be used to create kinematically equivalent variable joints that are geometrically different. The results were used to create two new reconfigurable mechanisms that utilize the synthesized variable joints. The first reconfigurable mechanism is a four-bar mechanism that performs a rigid body guidance task not possible using conventional four-bar theory. The second mechanism uses variable joints in a 3-RPR parallel mechanism for singularity avoidance without adding redundant actuation

Profile Synthesis of Planar Rotational–Translational Variable Joints

This paper presents an approach to the profile synthesis of planar, variable joints by combining higher variable joints. The possible permutations of planar, variable joints that change from a rotational to translational motion will be enumerated. A method will be provided to determine the profiles of variable joints, and a practical example will be presented to illustrate the proposed method

Synthesis of a Reconfigurable Four-Bar Mechanism with Variable Joints

This article introduces a reconfigurable four-bar mechanism. The mechanism uses a rotational-translational variable joint to switch between a RRRR four-bar and a RRRP1 four-bar. The ability to transition between two types of four-bar mechanisms allows the reconfigurable four-bar mechanism to complete a rigid body guidance task not possible by either a RRRR four-bar mechanism or a RRRP four-bar mechanism. The reconfigurable mechanism reduces the number of required actuators in the mechanism