No description available.

No description available.

No description available.

An object model based on the principle of duality where a plane has a point as a dual and a point has a plane as a dual is presented. Using this representation we present methods for performing intersection detection and face overlap checks to determine if a parallel jaw gripper is in a position to execute a valid grasp. Valid grasps are ones physically realizable and can lift an object when it is assumed that the gripping forces and the friction coefficients are large enough to keep the object from slipping. The objects considered are polyhedra and valid grip checks for both convex and concave objects are developed. A generate and test method for synthesizing valid grasp positions is also presented. / Master of Science

A novel robot gripper control system is presented which uses PVDF piezoelectric sensors to actively damp exerted force. By using a low-input-resistance amplifier to sense the current developed by the PVDF sensor, an output proportional to the rate of change of the force exerted by the gripper is obtained. The signals from the PVDF sensor and a strain gauge force sensor are arranged in a proportional and derivative (PD) control system for the control of force. The control system was tested on an instrumented Rhino XR-1 manipulator hand. The capabilities of the control system are analyzed analytically, and verified experimentally. The results for this particular gripper indicate that as much as 900% improvement in force step response rise time, and 300% reduction in overshoot are possible by inclusion of the PVDF sensor. / Master of Engineering

Parallel robotic manipulators are generally believed to be stiffer under load and more precise than conventional serial manipulators. This is because of their closed loop construction which allows forces to be shared through multiple paths to the ground. Unfortunately, most proposed parallel manipulator designs have severe workspace restrictions. The introduction of Variable Geometry Trusses (VGT’s) represents an opportunity to overcome this limitation. The lack of stiffness in many serial manipulators is primarily due to compliance at the joints. The disadvantage of the series connected device include limitations in lilting capacity and vibration problems. Difficulties of this sort result from the cantilever structure of the device. These factors often limit the degrees of freedom that can be provided in the serial configuration. By replacing the revolute joints with the ‘VGT joints’, it may be possible to add considerable rigidity at the joints and hence design a highly dextrous manipulator. The objective of this thesis is to study the feasibility of a design of manipulators using Variable Geometry Trusses. A modeling scheme capable of solving the inverse problem in closed form and finding the range of all possible solutions for a planar VGT has been presented. Another aspect that has been dealt with is in utilizing the extra degree of freedom that becomes available in the proposed manipulator. Enhancing the performance of the manipulator by optimizing relevant parameters has been carried out for a demonstrative case involving a planar truss. / Master of Science

Robotic mechanisms are defined in this dissertation to be closed-loop, in-parallel actuated mechanical devices possessing several degrees-of-freedom. Parallel robotic mechanisms have recently received attention in the robotics literature as a potential alternative to the existing serial industrial robot. Serial robots are in a cantilever configuration which makes them relatively compliant and Ieads to poor accuracy. Many serial manipulators have motors that are carried on moving links which limits dynamic performance. Robotic mechanisms are in a parallel configuration which provides excellent stiffness, load-bearing, and accuracy. Robotic mechanisms combine the advantages of serial robots and closed-loop single-degree-of-freedom mechanisms to form a versatile new robotic tool. This dissertation presents theoretical kinematic analysis and design of planar robotic mechanisms. The topics covered are type and number synthesis, kinematic position solution, velocity and acceleration analysis, kinetostatic analysis, workspace optimization, and link interference avoidance. Throughout this work, comparisons are made among three general manipulator configurations: serial, parallel-serial, and fully parallel. Strengths and limitations are discussed for each configuration type. This investigation provides the analytical foundation for implementation of planar robotic mechanisms. Closed-form solutions to the kinematic position, velocity, and acceleration problems are presented. Manipulator reachable hand areas are maximized. An underlying theme of this work is tradeoffs between competing factors relating to various configurations of parallel robotic mechanisms; these tradeoffs are important design considerations. The recommendation of this dissertation is to pursue practical development of robotic mechanisms for general industrial manipulation tasks. / Ph. D.

In this research we develop an integrated approach to optimally sequence robot operation in a workcell. The workcell represents a f1owshop operation with multiple robots transporting jobs among machines. A buffer of infinite capacity is available ahead of each machine. A robot transports jobs from buffers to machines and from machines to buffers. The robots used in the system are 5 jOint cylindrical coordinate robots. All the robots are identical in design and capability. For the type of robot used in this study its closed form inverse kinematic solution is known. The objective is to determine the sequence of robot operations so as to minimize the total time needed to complete all jobs (known as makespan). The integrated approach consists of determining optimal robot task sequences using a branch and bound procedure. and a graphical simulation procedure to display the robots as they perform transport operation. The branch and bound algorithm, which is an implicit enumeration scheme, is used to derive several near optimal robot task sequences. For the branch and bound algorithm. each node is a transport operation. Lower bound on the makespan is machine based and is computed at each node for further branching. The graphical simulation is used to detect interference among robots which is hard to be incorporated in the branch and bound procedure. Infeasible robot sequences are discarded and other solutions from the branch and bound procedure are displayed using the graphical simulation procedure to determine a near optimal and feasible sequence. The integrated approach is implemented on a prototype system. A command driven general purpose graphics system MOVIE.BYU is used for the graphical simulation of the robotic workcell and robot motion. The entire system is available in an integrated environment. A powerful programming language Rexx is used to manage various programs and data. Also, intermediate Rexx programs are generated during execution to allow MOVIE.BYU to edit and display animation data on the Tektronix 41XX series of terminals. The entire system is flexible and modular to be able to be used for various different applications. / Master of Science

Typescript (photocopy). / Digitized by Kansas Correctional Industries

Call number: LD2668 .T4 1985 R42 / Master of Science