27-03-2014, 02:38 PM
Pick and Place Robotic Arm Controlled By Computer
Pick and Place Robotic.pdf (Size: 1.7 MB / Downloads: 80)
ABSTRACT
Robot manipulator is an essential motion subsystem component of robotic system for
positioning, orientating object so that robot can perform useful task. In the field of
robotics, there are five types of robot configurations that are SCARA, articulated,
Cartesian, cylindrical and spherical. In this research, the focus is on 5 DOF articulated
arm since it mimic to human arm. Articulated arm consists of revolute joints that allowed
angular movement between adjacent joint. The arm's rotating base is powered by a single
large-scale servo. Mounted to the base is an elevation joint, or shoulder, that can move
the arm through 180 degrees, from horizontal to vertical on each side. The shoulder uses
two large-scale servos, working together to provide the torque needed to lift the rest of
the arm, as well as any object that it may be grasping. Attached to the shoulder piece is an
elbow that can move through 180 degrees, also powered by a large-scale servo. The wrist
is made up of three standard servos and can move through 180 degrees, as well as
rotating the gripper clockwise and counterclockwise. Attached to the wrist is a three-
fingered gripper that utilizes a unique design built around a single standard servo. The
revolute geometry allows the robot arm to reach any point within a half-sphere, having
the shape of an inverted bowl. The radius of the half-sphere should be the length of the
arm when its shoulder, elbow, and wrist are straightened out.
Introduction
Robot is an integral part in automating the flexible manufacturing system that one
greatly in demand these days. Robots are now more than a machine, as robots have
become the solution of the future as cost labour wages and customers' demand. Even
though the cost of acquiring robotic system is quite expensive but as today's rapid
develooment and a verv high demand in uualilv with I S 0 (International Standard
Organization) standards, human are no longer capable of such demands. Research and
develooment of Suture robots is movinlr at a verv raoid oace due lo the constanllv
imoroving and uograding of the aualitv standards of oroducts.
Project Background
The arm's rotating base is powered by a single large-scale servo that
m in a half-circle (180 degree) arc. Mounted to the base is an
rotates the rest of the a
elevation joint, or shoulder, that can move the arm through 180 degrees, from
horizontal to vertical on each side. The shoulder uses two large-scale servos, working
together to provide the torque needed to lift the rest of the arm, as well as any object
that it may be grasping. Attached to the shoulder piece is an elbow that can move
through 180 degrees, also powered by a large-scale servo. The wrist is made up of
three standard servos and can move through 180 degrees, from a straight position to
doubled back, as well as rotating the gripper clockwise and counterclockwise.
Attached to the wrist is a three-fingered gripper that utilizes a unique design built
around a single standard servo. The revolute geometry allows the robot arm to reach
any point within a half-sphere, having the shape of an inverted bowl. The radius of the
half-sphere should be the length of the a
m when its shoulder, elbow, and wrist are
straightened out.
Material Selection and Considerations
The most suitable material to fabricate the structure of the arm has to be light
and strong. Otherwise, the servo motor will not be able to pull up the arm and to
perform the desired turning degree. Among the materials that can be considered to
fabricate the structure are aluminum, perspex, plastic polymer and carbon fiber. In
choosing the fabrication materials, the aspect of availability of the materials, the
overall cost and the flexibility to be shaped, should also be taken into consideration.
Thus among the four materials considered, the aluminum is the most ideal material to
be chosen as fabrication material.
Design The Mechanism and Fabrication of the Robot Arm
The mechanical structure of shoulder, elbow and wrist form the main part of
the robot arm.The main problem in this part is on how to attach the servo motor onto
the section or joint to achieve the desired turning degree level. Besides, the way on
how to combine the a
m component should also be considered in order to achieve the
intended degree of freedom. Autodesk Inventor and Autodesk AutoCAD are used to
draw and to simulate the mechanical design of the robot arm.
Robot Geometry
In the field of robotics, there are five types of commonly used robot arm
configurations, each named according to the combination of shoulder, elbow and
wrist joints. Each of the commonly used types employs simple revolute or prismatic
joints. The five types are the rectangular coordinate (this includes both floor and
gantry mounts), spherical coordinate (polar), cylindrical coordinate, revolute
coordinate and the Self Compliance Automatic Robot Assembly (SCARA).
Design Evaluation
The evaluation stage is to review the design whether it has met the requirement or not.
If the design has not meet the requirement especially in terms of stability, then the
redesign step is done and the structure will be modified. If necessary, the redesigning
step will also involve literature review until the requirement is fulfilled. When the
requirements have been fulfilled, the mechanical part is completed.