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University of Florida - Design and Manufacturing LaboratoryAndres Flores
This is a team-driven course in which Mechanical Engineering students are placed in teams of four and tasked with developing a cost-efficient and robot that collects tennis balls and golf balls in a small arena designed by the course instructor. The two types of balls are placed in a single bucket and the robot is tasked with collecting the balls in a ball hopper. While in the ball hopper, the balls are to be sorted (tennis balls and golf balls are to be separated), then transported to the two buckets at the arena exit. The tennis balls are dispensed into one bucket and the golf balls are dispensed into the other bucket.
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1. Ball screws achieve high efficiency with low friction between rolling balls in the screw shaft and nut.
2. They are composed of a screw, nut, and balls, and screws are classified by manufacturing method (rolled or ground) while nuts are classified by recirculation method.
3. Key specifications for ball screws that must be considered include screw diameter, lead, ball diameter, screw thread dimensions, ball center diameter, and accuracy grades for lead and mounting surfaces.
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Baseball is an exciting sport in terms of CFD. Depending on how the pitcher throws the ball, the ball moves in an unexpected direction. From a spinless knuckleball to a four-seam fastball with very high speed and rotation. Such various pitches and conditions are a very interesting subject in terms of CFD.
In this slide, a basic analysis of the knuckleball, two-seam, and four-seam fastballs is performed and the pitching conditions for a more effective two-seam fastball are shown.
The simulations were performed by using the OpenFOAM.
Great plains precision seeding system 2010 p & 2020p PartCatalogs Net
This document is a parts manual for Great Plains Precision Seeding Systems models 2010P and 2020P from 2010-2020. It contains 14 sections that provide exploded diagrams and part lists for the major components of the seeder, including the box assembly, metering system, drive, openers, press wheels, decals, optional markers and more. Safety warnings are included to note potential hazards. Copyright and trademark information is also provided.
Great plains precision seeding system 2010 p & 2020p
Golf Chipper RobotV1.6
1. Golf Chipper Robot
Sponsor: Dr. Tom Mase
Advisor: Dr. James Meagher
Date: March 14, 2009
Kevin Ebberts Kebberts@gmail.com
Samson Holmes Stholmes@calpoly.edu
Kevin Swanson Kejardon@gmail.com
Jason Swartz Jswartz86@gmail.com
2. Executive Summary
Testing golf shots at low impact speeds is a problem for
existing equipment. The traditional Iron Byron, a robot
used to recreate golf swings, cannot recreate shots of
20 to 50 yards. A consistent way of testing golf clubs
for shots of these yardages is needed. Worm Burner
Dynamics proposes to construct a mobile two bar
mechanism to hit these golf shots. The mechanism will
rely on a gearing system to deliver the club head to the
golf ball in a repeatable and adjustable way. The
chipper is adjustable in different ways to account for
subtle changes in actual player’s golf swings. After
construction, the chipper will go through a verifying
stage to determine if the chipper meets the design
requirements.
3. Table of Contents
Introduction.................................................................................................. 6-7
Sponsor Background.........................................................................................6
Problem Statement...........................................................................................6
Objective..........................................................................................................6
Design Specifications .................................................................................... 6-7
Existing Equipment.......................................................................................8-9
Top Swing ........................................................................................................8
Iron Byron.....................................................................................................8-9
Design Development ............................................................................... 10-16
Conceptual Designs................................................................................... 10-13
Base.................................................................................................. 10-11
Power................................................................................................ 11-12
Grip................................................................................................... 12-13
Concept Selection...........................................................................................13
Preliminary Analysis .................................................................................. 14-15
Launch Angles .........................................................................................14
Necessary Club Head Speed .....................................................................14
Swing Kinematics............................................................................... 15-16
Description of Final Design ..................................................................... 17-27
Nomenclature.................................................................................................17
Power....................................................................................................... 17-19
Gearing System........................................................................................ 19-20
Grip System ............................................................................................. 21-23
Ratchet and Crank .................................................................................... 23-24
Cost Analysis ..................................................................................................25
Safety Considerations .....................................................................................26
Maintenance and Repair ..................................................................................26
Design Verification Plan.................................................................................27
Strain Gauge Correlation.................................................................................27
Management Plan.......................................................................................... 28
4. Figure List
Iron Byron Figure (1)...........................................................................................8
Iron Byron’s Gearing System Figure (2)................................................................9
Base Figure (3)..................................................................................................10
Floor Locker Disengaged Figure (4) ....................................................................11
Floor Locker Engaged Figure (5).........................................................................11
Torsion Spring Figure (6) ...................................................................................12
Gripping Mechanism Figure (7)..........................................................................13
Carry Distance vs. Club Head Speed Figure (8) ..................................................15
Samson Holmes hitting a 60 yard wedge shot Figure (9) ....................................16
General nomenclature for the golf chipper robot Figure (10) ...............................17
Exploded view of the hub assembly Figure (11) ................................................. 18
Hub assembly with torsion spring, main shaft, and roller bearing Figure (12) ......19
Rotated view of arm mechanism. Figure (13) .....................................................19
Chipper from rest to top of back swing position. Figure (14) ...............................20
Professional golfer J.J. Henry’s swing[2] Figure (15) ...........................................20
“Wrist” system comprising of grip plate and grip clamp. Figure (16) ...................21
Grip mechanism rotated to different relative hand positions. Figure (17) .............21
Grip clamp bottom with tapered slot for golf club grip. Figure (18) ......................22
Grip Clamp Bottom (bottom face) with counter bores. Figure (19) ......................22
Grip clamp in different height positions along grip plate slot. Figure (20) .............23
Back side of hub with ratchet and pawl. Figure (21) ...........................................24
Hazard sticker placed in various locations on the Chipper Figure (22) ..................26
5. Table List
Design specifications and tolerances Table (1) ......................................................7
Decision Matrix Categories and Choices Table(2).................................................12
Winning Concept Selections Table (3) ................................................................13
Bill of Materials and cost breakdown for the Golf Chipper Table (4) .....................25
6. - 6 -
Introduction
Sponsor Background
Dr. Tom Mase conducts product testing at California State Polytechnic
University as an unbiased source for various companies and magazines. He
has been featured multiple times in Golf Magazine in a section called, “Ask
Dr. Tom,” in which he answers golfer’s queries related to club design and
function.
Problem Statement
Testing golf shots at low impact speeds is a problem for existing equipment.
The traditional Iron Byron, a robot used to recreate golf swings, cannot
recreate shots of 20 to 50 yards. Shots in this range are of increasing
interest because of the United States Golf Association’s new restrictions on
cross sectional area and edge sharpness of golf club grooves. Also, the
effect of groove deterioration on spin rate is of interest. A consistent way of
testing golf clubs for shots of 20 to 50 yards is needed.
Objective
The main goal of this project is to produce a mechanism capable of hitting
pitch shots so Dr. Tom Mase can use it to analyze the effects of wedge
groove geometry, and groove deterioration. In order to meet this goal, we
have developed design specifications from our sponsor’s functional
requirements in order to meet our customer’s needs.
Design Specifications
1. Launch the ball at speeds between 25 and 55 mph
2. Launch the ball at an angle of 28 to 40 degrees
3. Launch the ball between 10 to 50 yards
4. Land the ball within 2 yards of its target
5. Adjustable range in increments of 5 yards or less
6. Adjustable shoulder height
7. Lockable wheels
8. Triggered remotely
9. Low time of club change
10. Low time of test reset
11. Controlled follow through
12. Black
13. Base within an area of 4x4 feet
7. - 7 -
Table 1 Design specifications and tolerances.
Spec.
#
Description Target Tolerance Risk Compliance
1 Ball Speed 25-55 mph - H A, T, S
2a Ball Angle 28-30 degrees - H A, T, S
2b Ball Angle 30-35 degrees - M A, T, S
2c Ball Angle 35-40 degrees - L A, T, S
3 Chip Range 10-50 yds - H A, T
4 Error in Range 2 yds Max H T
5 Adjustability 5 yds Min M A, T
6 Height Range 10 in. Min H I
7 Lockable Wheels - - M I
8 Remote Trigger - - M I
9 Club Change
speed
35 seconds Max M T, I
10 Reset Speed 10 seconds Max M T, I
11 Rebound 3 inches Max L T, I
12 Color Black - L I
13a Footprint Width 4 feet Max M I
13b Footprint Width 4 feet Max M I
8. - 8 -
Existing Products
Top Swing
Per our research, there exist two categories of testing robots currently on
the market. One product, Top Swing, uses the kinematics of a golf swing to
mimic a human swing for training purposes. This product grips the club
while the golfer grips the club and slowly moves along the path of a textbook
swing. In the interest of safety, Top Swing moves at a speed slower than a
typical swing, in order not to damage the golfer. This product is not suitable
for our task because it cannot hit a ball at full swing for the purpose of ball
testing.
Iron Byron
The other category of testing robots hit full golf shots. The most famous
product in this market is the commonly dubbed the “Iron Byron,” see Figure
1.
Figure 1. Iron Byron
The “Iron Byron” is named after famous golfer Byron Nelson, who was
known for his remarkably technical golf swing. The robot version is now the
gold standard in golf testing equipment. According to Golf Laboratories, a
manufacturer of the robot, the robot can simulate different types of swings.
It can mimic hook and slice type golf swings as well as low to high shot
trajectories. The robot mimics a human’s wrist break and rotation with the
gearing system shown in Figure 2. The wrist rotates the club a full 180° in
two axes (wrist axis and toe axis) relative to the arm. The position of the toe
axis is dependent on the position of the wrist axis (and vice versa) via the
9. - 9 -
stationary and rotating gear relationship. This dependency is linear, meaning
1' of wrist rotation equates to 1' of the toe axis rotation.
Figure 2. Gearing of wrist
The downfall with the “Iron Byron” is when it is required to hit chip or pitch
shots. The robot is incapable of hitting a high lofted wedge shot of 60 yards
or less.
10. - 10 -
Design Development
Conceptual Designs
Base
Our base plays a critical role in the design of our overall system.
Requirements include lockable wheels and being no larger than four foot
square. It must also be stable enough to give repeatable shots while
withstanding the momentum change of the swing of the golf club. A rough
drawing of the base is shown in figure 3.
Figure 3. SolidWorks rendering of Base
From this drawing, you can see the base is fairly robust, with 3 in square
steel bar stock. Pending further analysis, square tubing may be used. The
shaft which is connected to the main drive mechanism will be threaded
through the hole at the top with either a bearing or bushing. We have a
couple different options for the wheels. There are many different types of
casters available, locking and non-locking. For the non-locking type there is
a locking mechanism available as seen in Figure 4 and Figure 5 which is
bolted next to the casters and will raise up the base just to clear the wheels.
This option will be more desirable because it will provide more stability than
simply locking the wheels.
11. - 11 -
Figure 4. Locker in disengaged position
Figure 5. Locker in engaged position
Power
Power is a critical element of our design. If we cannot successfully store
enough potential energy, our design will fail its fundamental purpose, hitting
a golf ball an acceptable distance. In order to focus on a few avenues of
investigation, each team member constructed a “decision matrix” or bracket
of ideas that competed in multiple weighted areas of our functional
requirements to find the best concept for the overall design. Each matrix
had various methods of achieving desired club head speeds including
motors, pendulums, linear springs, and torsion springs. When comparing
our individual decision matrices, it became apparent that the team agreed
on two designs – one utilizing a motor and one utilizing a torsion spring.
Using a motor for this application has an array of issues. Motors require
some consumption of power – electricity, combustion gas, or photovoltaic
panels – none of which are feasible for our design. Electric power requires
use of a power cord/ generator and limits the mobility of the design. Gas
combustion and photovoltaic panels are each expensive increase the
12. - 12 -
complexity of our design, an unfavorable circumstance. Consequently, we
decided on a design utilizing torsion springs. Torsion springs are compact,
simple, can be easily hidden, and have immense energy storage capability.
We are currently calculating the required torque for our desired club head
speed. A torsion spring similar to what our design calls for is shown below in
Figure 6.
We plan to attach the middle of the spring to the structure and the free end
to a pad that will be deflected by the club arm. With this orientation, the
club will separate from the spring as opposed to deflecting it in the opposite
direction, avoiding damage to the spring. Until we determine a required
torque, we cannot speculate about dimension and cost, as many companies
do not post pricing on their websites, and we would prefer to know more
about the spring specification before contacting vendors. In the case that a
single torsion spring is not cost feasible, we have considered a second
option. Attached is a preliminary sketch of several smaller torsion springs,
in parallel, to achieve the same torque as one larger torsion spring. Aligned
along a shared shaft, several smaller torsion springs could potentially offer
the torque of a larger spring, but at the cost of space. Both configurations
satisfy functional requirements of power increments, simplicity, and ease of
construction.
Grip
In order to be able to repeatedly test a golf club, our design must be able to
hold a golf club without it moving during a test. In addition, it has to be
adjustable for various sizes of clubs, and preferably be easy to switch clubs
in and out, without requiring extra small parts that might be lost. A number
of ideas were considered for this, including tapers, vice grips, and even a
material to wrap around the club then tighten and latch down.
Currently, the kind of grip we expect to use is illustrated by Figure 7. It will
be two half-cylinders with a joint, with threads on one half and nuts on the
Figure 6. Torsion Spring
13. - 13 -
Figure 7. Half of grip clamp
other half to tighten the cylinder grip to the club. With this kind of design,
there would be no parts that would even come off the robot, except possibly
ordinary nuts that would be purchasable anywhere. In addition, the grip can
be plenty tight for any club size, so it won't move around during a swing.
Concept Selection
Our method of concept selection involved what we have been calling a
“Decision Matrix,” which is a weighted bracket, used to compare the
effectiveness of all design concepts at meeting the design’s functional
requirements (Appendix A). The first step was to split up the design into
subsystems, as noted in the previous section, where different possible
design choices were chosen for each, shown in Table 2.
Table 2. Decision Matrix Categories and Choices
Power Base Grip
Torsion Spring Wheels Quick Release
Pendulum Tripod
Vice Grip
Pliers
Pulley Quad pod Screw/Bolts
Linear Spring Cone Taper
Motor
Locking
Wheels
Solid
The design features in italics in Table 2 are features possessed by the
current chipper; these became the baseline in the decision matrix. Each
concept’s predicted effectiveness was then compared to the baseline of the
14. - 14 -
feature currently fulfilling that role. If the concept is predicted to be more
effective than the current part, it was given a “+,” if it was predicted to be
less effective it was given a “-,” and if it was predicted to be equally as
effective, it was given a “S” (meaning SAME). The concept tallies were
weighted and scored at the bottom of the matrix. The winning concept
selection is shown in Table 3.
Table 3. Winning Concept Selections
Power Base Grip
Torsion
Spring
Quad pod
Quick
Release
Preliminary Analysis
Launch angles
At the Cal Poly Golf Lab a launch monitor was used to determine the range
of golf ball launch angles for low to high launch characteristics. Multiple
scratch, zero handicap, golfers hit balls using a 56 degree sand wedge in
front of a launch monitor. They were asked to hit a 50 yard golf shot, and to
strike the ball using a wide range of attack angles, ranging from very steep
to very shallow. The launch angle range for a typical 20-60 yard shot is 28-
34 degrees.
Necessary club head speed
Using a coefficient of restitution, COR or smash factor, of about one, there is
a direct correlation between the ball speed and club head speed.
Furthermore, neglecting the effects of lift and drag on the golf balls flight
results in a simple relationship between distance, launch angle, and ball/club
head speed, shown in equation (1).
𝑉 = √
𝑥𝑔
2 cos 𝜃 sin 𝜃
(1)
Where V is the ball/club head speed [ft/s], x is the carry distance [ft], g is
the gravitational constant [ft/s2], and 𝜃 is the launch angle in degrees. This
relationship gives us a good estimate of the necessary head speed required
to hit different yardage golf shots at different launch angles, seen in figure
8.
15. - 15 -
Figure 8. Relationship between carry distance and necessary club head speed for
various launch angles
Kinematics of the Golf Swing
In order to create a robot to mimic a human golf chip, the kinematics of a
human golf chip shot must be quantified. We quantified the kinetics of
multiple golf swings through motion capture technology, developed during a
senior project last year. The specific data that was of interest were the
rotational speed of the extended arm, the left arm for right handed golfers,
and the rotational speed of the wrists relative to the arm. Through analysis
of videos taken of low handicap golfers, specific conclusions were made
pertaining to recreating a human’s golf swing. Through the hitting area a
golfer’s wrists are rotating about twice as fast as the arms are.
0
10
20
30
40
50
60
70
0 10 20 30 40 50 60 70
Ball/ClubHeadSpeed[mph]
Carry Distance [Yards]
26 Degrees
30 Degrees
34 Degrees
40 Degrees
16. - 16 -
Figure 9. Samson Holmes frame by frame hitting a 60 yard wedge shot near
impact from 1 to 4 being impact
Most of the club head speed generation occurs very near the hitting area, as
can be seen by the little arm movement, and high wrist rotation in figure 9.
To accurately mimic a human’s swing we needed to mimic the wrist action of
the golfer. In order to accommodate this needed wrist action, we
implemented the gearing system described in the final design
17. - 17 -
Description of Final Design
Nomenclature
The general mechanism of the golf chipper is a torsion spring connected via
a main shaft to an arm that holds a golf club. When the torsion spring is
loaded, the mechanism is released causing the arm to swing the golf club.
The golf chipper consists of the main components shown in figure 10. The
hub houses the powering mechanism. The crank bar is used to load the
mechanism, and is removable. The grip secures the golf club to the golf
chipper, and is adjustable in three respects: height, hand position relative to
the ball, and lie angle.
Figure 10. General nomenclature for the golf chipper robot
18. - 18 -
Figure 11. Exploded view of the hub assembly, not including the ratchet and pawl
Power
The power behind the chip shot swing is contained in the system Hub shown
in figure 11. The Hub is fixed around a large torsion spring, which is
attached to a rotating shaft. When the chipper arm is pulled back, the main
shaft deflects the spring in a clockwise direction, and the free end on the
outermost coil is stopped by a ridge on the inside rim of the hub,
constraining the spring and storing energy for the swing. The hub is shown
in Figure 12, the main shaft is highlighted in blue for clarity.
19. - 19 -
Figure 12. Hub assembly shown with torsion spring, main shaft, and roller bearing.
Hub top is not shown
Gearing System
Refer to appendix C in relation to the following for a visual depiction of the
gearing system. The arm of the robot, connected to a central hub, rotates
about a fixed point. The hub contains the torsion spring powering
mechanism described in the power section. Connected to the hub top is a
stationary fixed gear, linked to the rotating gear at the end of the arm by a
chain and sprocket. The “wrist” of the robot is essentially a gear attached to
the gripping mechanism that rotates as a result of the arm gear rotating
(figure 13).
Figure 13. Rotated view of arm mechanism
20. - 20 -
It is important to note that this movement is always in the plane of the
swing motion. The gearing system will allow for control over the position of
the golf club, while maintaining the 2 bar linkage model. The “hand” speed,
or end of the arm, to club head speed ratio of the robot is dependent of the
gearing ratios between the two rotating gears at the end of the arm.
Ideally, the club head speed will be about twice the “hand” speed, which is
not only a factor of the relative lengths of the arm and club, but also the
relative rotational speeds of the “wrist,” and central hub. This gearing also
much resembles the look of a natural golf swing. When the arm of the robot
is parallel with the ground, the club is perpendicular with the ground,
accurately mimicking a golfer’s swing.
Figure 14. Chipper from rest to top of back swing position
The robot will mimic the key positions of a professional golfer’s swing, as
seen by comparing figures 14 and 15.
Figure 15. Professional golfer J.J. Henry’s swing [2]
21. - 21 -
Gripping System
The gripping system is comprised of 3 main components: the grip plate, and
the grip clamp top and bottom (figure 16). The grip plate can rotate a small
amount in the plane of rotation, giving adjustability for relative hand
position. The grip clamp will secure the golf club, and can adjust in the
direction of the arm (at rest), making the effective length of the arm and
club system adjustable up to 4 inches.
Figure 16. “Wrist” system comprising of grip plate and grip clamp
The grip plate is attached to the wrist gear via two bolts. The main
adjustability of the plate is adjusting the relative “hand” position relative to
the ball, influencing the angle of attack. Meaning the hands can be pressed
forward relative to the ball producing a steep aggressive angle of attack, or
the hands can be held back producing a shallow angle of attack (figure 17).
Figure 17. Grip mechanism rotated to different relative hand positions
22. - 22 -
The grip of the golf club is secured to the chipper via the grip clamp. The
grip clamp is two blocks of ultra-high molecular weight polyethylene with
tapered diameters machined along their length, thus leaving a slot for the
club’s grip to rest (figure 18).
Figure 18. Grip clamp bottom with tapered slot for golf club grip
Four bolts, two on each side, secure the club in the grip clamp. The grip
clamp bottom has threaded holes for easy securing of the golf club. The grip
clamp is attached to the grip plate via two bolts in conjunction with two
nuts. The head of the bolts will be located inside a counter bore on the
bottom face of the bottom grip clamp, as seen in figure 19.
Figure 19. Grip Clamp Bottom (bottom face) with counter bores
23. - 23 -
This counter bore will allow for a secure linkage between the grip clamp and
grip plate, while maintaining the necessary clearance underneath the grip
clamp for the gear. This feature will allow the grip clamp and golf club
combination to slide along the slot in the grip plate, making the effective
length of the arm and club system adjustable up to 4 inches (figure 20).
Figure 20. Grip clamp in different height positions along grip plate slot
Ratchet and Crank
Loading and releasing the system is one of the fundamentals of our design.
We chose to use a ratchet and pawl system to load the spring, and trigger
the mechanism. The main benefit to having a ratchet and pawl system is
fine adjustability that comes with having 72 teeth on the ratchet. This will
allow the user to fine tune the power delivered to the ball, and to fine tune
the yardage the ball will travel. The back side of the hub with ratchet and
pawl system is shown in figure 21. Note that the triggering system is not
shown in figure 21. A spring will keep the pawl pressed against the ratchet
while the user loads the spring. A solenoid with a remote trigger is used to
release the pawl from its engaged position.
24. - 24 -
Figure 21. Back side of hub with ratchet and pawl
The main shaft in figure 12 has a through hole fit for a long bar. The bar is
a level to aid in loading the mechanism’s spring. The bar will be
approximately 3 feet long for added leverage.
Feet
Stability and mobility are two of the chipper’s functional requirements which
often conflict with each other. The chipper needs wheels in order to be
transported, but must be completely stable when used as a research tool.
The solution for this dilemma is a matching set of floor-to-frame feet which,
when extended, lift the casters and the structure an inch off of the ground,
as shown in Figure 10. This elevation gives the chipper a firm, stable
platform, allowing it to operate with the highest possible repeatability.
25. - 25 -
Cost analysis
Table 4 shows the predicted cost breakdown of the Golf Chipper. The prices
of the two gears are missing as we are still awaiting pricing quotes from the
manufacturer. The torsion spring quote is also a manufacturer estimate, but
we don’t expect the cost to reach much higher than $100. With a total cost
of $1,385, we are well below our budget of $2000. This breakdown doesn’t
take shipping costs into account, but we expect to purchase most of these
parts in town, avoiding the extra cost of shipping. We will machine the more
elementary parts ourselves, but advanced welds and CNC programmed cuts
will need to be machined, so we have set aside $500 for machining, bringing
our total to $1,885.
Table 4. Bill of Materials and cost breakdown for the completion of the Golf
Chipper
Product Quantity
Unit
Price
Total
Price
Wing Bolts 4 $1.00 $4.00
6"x6"x12" 6061 Aluminum Square 1 $377.55 $377.55
Main Shaft - 5947K32 1 $44.66 $44.66
Arm Shafts 2 $21.08 $42.16
Main Shaft Bearing 2 $20.22 $40.44
Main Shaft Bearing Liners 2 $13.00 $26.00
Arm Bearing 4 $19.46 $77.84
Arm Bearing Liner 4 $10.05 $40.20
Arm 1 $51.02 $51.02
Torsion Spring 1 $800.00 $800.00
Transition Gear 1 $0.00
Club Gear 1 $0.00
Caster 4 $20.00 $80.00
Support Leg 4 $20.00 $80.00
Chain 1 $18.42 $18.42
Fixed Sprocket 1 $24.81 $24.81
Transition Sprocket 1 $17.74 $17.74
Ratchet 1 $18.84 $18.84
Pawl 2 $3.75 $7.50
Steel Tube 3 x 3 x 1/4 thick 4.0 ft 3 $48.44 $145.32
Steel Tube 3 x 3 x 1/4 thick 6.0 ft 2 $72.66 $145.32
Derailleur 1 $69.95 $69.95
Subtotal $1,411.77
Total Labor $500 $2,711.77
26. - 26 -
Safety Considerations
When loaded, the chipper’s torsion spring is capable of upwards of 100 ft/lbs
of torque, and can be very dangerous if the proper safety measures are not
taken. In order to protect the user, a few precautions have been factored
into the design. A ratchet system on the back of the hub keeps the arm
from swinging if the user lets go of the crank bar during loading. The pawl is
then triggered from a safe distance, outside the swing path, by the use of a
small push/pull solenoid that disengages the pawl and releases the arm.
The chipper also has a variety of moving parts (sprockets, gears chains),
which is why hazard stickers are placed on many surfaces warning of the
possibility of injury if any tools or body parts are caught in these parts
during operation as shown in Figure 22.
Figure 22. Hazard sticker placed in various locations on the Chipper
Maintenance and Repair
The chipper does not have many foreseeable maintenance issues, but for the
sake of assembly and transport, we have made certain design decisions that
make the chipper easier to repair and maintain. We have avoided welds and
press fits whenever possible, choosing to key most fixed shafts, requiring
only the removal of the key to disassemble the mechanism. We have also
added a chain tensioning device, a bike derailleur, to the chain for ease of
replacement and assembly. This way, the chain can slip on and off the arm
by retracting the derailleur, instead of removing a link in the chain or taking
apart any of the assembled mechanisms.
27. - 27 -
Design Verification Plan
Strain Gage Correlation
Students in ME 410, Experimental Methods, are experimenting with strain
gages attached to wedges, measuring the stresses in the shaft when striking
a golf ball. When the chipper construction is completed, we will conduct
similar tests and compare the strain encountered by the club when swung by
the chipper and the students in ME 410. If our chipper can produce similar
results, it will be an indicator that we have successfully simulated a human
swing, our original goal.
28. - 28 -
Management Plan
In order to efficiently complete this task we will adopt a “divide and conquer”
management style. Through personality evaluation and completion of
previous tasks, we have acknowledged different strengths in each of our
team members. We have identified four main aspects of this project:
Technical research, analysis/design, building/testing, and design report. All
four members of this group will participate in each aspect, but each will be
headed by one group member or “Task Lead (TL).” Samson Holmes
possesses prior knowledge pertaining to this project and has already begun
research trials with a high speed camera in order to dissect the human chip
shot, so he will be the Technical Research TL. Kevin Swanson is competent
in MatLab simulation/analysis and will be the Analysis/Design TL. Jacob
Swartz excels in prototyping/fabrication, has the ability to see the project as
a whole – Jacob will be the Building/Testing TL. Kevin Ebberts has an
expressive personality and a solid foundation in writing/literature – Kevin will
be the Design Report TL.
The robot itself is comprised of six subsystems – Base, club clamp, swing
arm, stored energy mechanism (spring, hydraulic cylinder, etc.), triggering
mechanism, and support post. These subsystems may be designed
independently or in concert – at this stage in the design process we are
unable to make a concrete decision pertaining to design order.
In order to plan the design process and project deliverables, we have
created a preliminary Gantt chart – located in the appendix. Currently, the
Gantt chart lacks specific deadlines for sub-system design/completion
because we have not yet decided on a design direction pending further
research and investigation.
29. Appendix
A. Decision Matrix
B. Possible Spring Configuration
C. Gearing Diagram
D. Deflection of Arm Calculation
E. Design Packet
31. Golf Chipper
Robot
Power Base Club Holder
Concepts 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 Torsion Spring
Criteria Wgt 2 Pendulum
Distance 4 + - - S + S S S S S S S S S S 3 Pulley
Increments 5 + S + S + S S S S S S S S S S 4 Linear Spring
Repeatability 5 + S + S + - + + S S + S S S S 5 Motor
Low cost 3 - - + S - + S S - S - + - S + 6 Wheels
Human Factors 3 S - - S + - S + - S - + - S + 7 Tripod
Human Swing 4 + + - S + S S S S S S S S S S 8 Quad pod
Height Adjust 4 S + S S S S S + - S - S S S S 9 Cone
Grip Security 4 S S S S S S S S S S S + + S - 10
Locking
Wheels
Weight 2 S - - S - S S - - S - S - S S 11 Solid
Ease of Assembly 2 S - - S - + - + + S + + - S + 12 Quick Release
Safe 4 + - - S - - S + + S + + + S - 13 Vice Grip Pliers
Club
Interchangeability 4 S S S S S S S S S S S + - S + 14 Screw/Bolts
Stability 4 + - - S S - - + + S + S S S S 15 Taper
Appearance 3 + - - S + S S + + S S S - S +
#+ 7 2 3 0 6 2 1 7 4 0 4 6 2 0 5
#- 1 8 8 0 4 4 2 1 4 0 4 0 6 0 2
#S 6 4 3 14 4 8 11 6 6 14 6 8 6 14 7
Weighted total 26
-
17
-
13 0 13
-
11 -1 23 1 0 3 20 -9 0 7
Decision Matrix