Analysis of a 5-DOF Robot Manipulator for Agriculture Applications
Date
2021-09-29
Authors
Journal Title
Journal ISSN
Volume Title
Publisher
ORCID
Type
Thesis
Degree Level
Masters
Abstract
A 5 degree of freedom (shown by \theta_{1-5}) robot was analyzed in this thesis for a better understanding of forward kinematic, inverse kinematic, and forward dynamic analyses. Using the forward and inverse kinematics, position of end effector (tip) of the robot can be predicted relative to base of the robot at any time, including while the robot is in motion. The analytical forward kinematic equations were derived using the Denavit-Hartenburg (DH) parameters by creating coordinate transformation matrices from the base of the robot to the tip. The inverse kinematic equations were then derived from the forward kinematic equations.Both sets of kinematic equations were then compared to a simulated model of the robot arm which was created in ANSYS rigid dynamics module.
Forward dynamic equations of the robot are used to determine forces required at each joints to produce motion. original method for determining the forward dynamics is a set of equations where the Newton-Euler equations for motion are applied to individual robot links for a serial robot (Craig 2005). As the robot arm concerned in this thesis is not a serial robot (each link attaches to only 1 following link), additional equations were created by analyzing free body diagram of outer link and upper link of the robot arm. After including additional equations, the analytical dynamic equations of the robot were complete. The same simulated robot arm as above was used to compare analytical results with simulated results.
The last section of this thesis presents a gradient optimization technique. Changing weight of the robot arm to a minimum will reduce torque requirements for joint motors, minimize power consumption, and reduce risk of soil compaction. Using a gradient search optimization, shape of the inner link is optimized subject to maximum deflection and maximum stress constraints. Once the optimization was completed, overall mass of the robot arm was reduced by about 49%. When the old inner link was replaced by the new optimized link the torque required of the inner link motor was reduced by about 11% when following a given trajectory.
Description
Keywords
Robot, optimization
Citation
Degree
Master of Science (M.Sc.)
Department
Mechanical Engineering
Program
Mechanical Engineering