Title page for ETD etd-112807-143951

Document Type thesis

Author Name Paradorn, Vasin

URN etd-112807-143951

Title An Impact Model for the Industrial Cam-follower System: Simulation and Experiment

Degree MS

Department Mechanical Engineering

Advisors
Robert L. Norton, Advisor

Keywords
follower
cam
cam-follower system
impact model
dynamic model

Date of Presentation/Defense 2007-10-11

Availability unrestricted

Abstract
Automatic assembly machines have many cam-driven linkages that provide
motion to tooling. Newer machines are typically designed to operate at higher speeds
and may need to handle products with small and delicate features that must be assembled
precisely every time. In order to design a good tooling mechanism linkage, the dynamic
behavior of the components must be considered; this includes both the gross kinematic
motion and self-induced vibration motion.
Current simulations of cam-follower system dynamics correlate poorly to the
actual dynamic behavior because they ignore two events common in these machines:
impact and over-travel. A new dynamic model was developed with these events. From
this model, an insight into proper design of systems with deliberate impact was developed
through computer modeling.
To attain more precise representations of these automatic assembly machines, a
simplified industrial cam-follower system model was constructed in SolidWorks CAD
software. A two-mass, single-degree-of-freedom dynamic model was created in
Simulink, a dynamic modeling tool, and validated by comparing to the model results
from the cam design program, DYNACAM. After the model was validated, a controlled
impact and over-travel mechanism was designed, manufactured, and assembled to a
simplified industrial cam-follower system, the Cam Dynamic Test Machine (CDTM).
Then, a new three-mass, two-degree-of-freedom dynamic model was created. Once the
model was simulated, it was found that the magnitude and the frequency of the vibration,
in acceleration comparison, of the dynamic model matched with the experimental results
fairly well. The two maximum underestimation errors, which occurred where the two
bodies collided, were found to be 119 m/s2 or 45% and 41 m/s2 or 30%. With the
exception of these two impacts, the simulated results predicted the output with reasonable
accuracy. At the same time, the maximum simulated impact force overestimated the
maximum experimental impact force by 2 lbf or 1.3%.
By using this three-mass, two-DOF impact model, machine design engineers will
be able to simulate and predict the behavior of the assembly machines prior to
manufacturing. If the results found through the model are determined to be
unsatisfactory, modifications to the design can be made and the simulation rerun until an
acceptable design is obtained.

Files
vparadorn.pdf

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Document Type	thesis
Author Name	Paradorn, Vasin
URN	etd-112807-143951
Title	An Impact Model for the Industrial Cam-follower System: Simulation and Experiment
Degree	MS
Department	Mechanical Engineering
Advisors	Robert L. Norton, Advisor
Keywords	follower cam cam-follower system impact model dynamic model
Date of Presentation/Defense	2007-10-11
Availability	unrestricted
Abstract Automatic assembly machines have many cam-driven linkages that provide motion to tooling. Newer machines are typically designed to operate at higher speeds and may need to handle products with small and delicate features that must be assembled precisely every time. In order to design a good tooling mechanism linkage, the dynamic behavior of the components must be considered; this includes both the gross kinematic motion and self-induced vibration motion. Current simulations of cam-follower system dynamics correlate poorly to the actual dynamic behavior because they ignore two events common in these machines: impact and over-travel. A new dynamic model was developed with these events. From this model, an insight into proper design of systems with deliberate impact was developed through computer modeling. To attain more precise representations of these automatic assembly machines, a simplified industrial cam-follower system model was constructed in SolidWorks CAD software. A two-mass, single-degree-of-freedom dynamic model was created in Simulink, a dynamic modeling tool, and validated by comparing to the model results from the cam design program, DYNACAM. After the model was validated, a controlled impact and over-travel mechanism was designed, manufactured, and assembled to a simplified industrial cam-follower system, the Cam Dynamic Test Machine (CDTM). Then, a new three-mass, two-degree-of-freedom dynamic model was created. Once the model was simulated, it was found that the magnitude and the frequency of the vibration, in acceleration comparison, of the dynamic model matched with the experimental results fairly well. The two maximum underestimation errors, which occurred where the two bodies collided, were found to be 119 m/s2 or 45% and 41 m/s2 or 30%. With the exception of these two impacts, the simulated results predicted the output with reasonable accuracy. At the same time, the maximum simulated impact force overestimated the maximum experimental impact force by 2 lbf or 1.3%. By using this three-mass, two-DOF impact model, machine design engineers will be able to simulate and predict the behavior of the assembly machines prior to manufacturing. If the results found through the model are determined to be unsatisfactory, modifications to the design can be made and the simulation rerun until an acceptable design is obtained.
Files	vparadorn.pdf