The document proposes and summarizes the design of an automated robotic work cell to assemble nut plates. The work cell aims to remove humans from repetitive assembly tasks that cause injuries. It will use a Denso robot with an end effector to place nut plates and set rivets using an air hammer. A rivet feeder and sliding anvil will feed and buck rivets. The process, work cell components, programming, and timeline are described in detail. Feedback is requested on the proposed solution and any potential pitfalls.

1. Design Review
Robotic Work Cell

2. Problem Statement
• Hundreds of nut plate assemblies are built everyday using human
labor.
• This work is monotonous and physically taxing for the workers
involved, often resulting in injury due to repetitive motions.
• In addition to causing workplace injury, the repetitive nature of these
tasks result in an accumulation of process errors.
• The goal of this project is to create an automated work cell centered
on an industrial robot which can tirelessly and consistently perform
these assembly tasks which are ill-suited for human workers.

3. Design Goals and Deliverables
• Safety – remove humans from the manufacturing task, create a
process that adheres to safety requirements where humans may
interact with robot.
• Create a proof of concept for a process that may be adapted for
production.
• Create thorough documentation for future students and design
teams, including robot operation and programming tutorials.

4. Specifications
• Can be adapted to various nut plate assembly tasks
• Depth of rivets must be meet tolerance requirement of -0/+0.010
inches
• Minimum distance of two rivet head diameters between rivets and
part edge
• Nut plates must be clocked within 2 degrees of drawing specifications
• Nut plates must be within 0.030 inches of drawing specifications
• Assembly requires minimal manual operations

5. Robotic Work Cell Capabilities
• Denso Robot
• VS-6577GM-B Six-axis articulated
robot
• High speed and repeatability
• 7 kg maximum payload
• WINCAPS III software
• Allows programming of robot motions
without operating the robot
• Provides a 3D simulation environment
• 3D objects from CAD may be imported
for a more accurate simulation
• Real time robot movement can be
monitored

6. Robotic Work Cell Capabilities
• University of Idaho safety enclosure
• Constructed from 80/20 framing
system and polycarbonate sheets
• eGard system
• Modular safety device which regulates
external control and safety features
• Emergency stop with key lock
• Solenoid locking actuator
• External program control
• Step stop
• Start
• Operating light
• Program selector

7. Changes to Proposed Process
• Primary goal is to move nut plate positioning and rivet setting process
to the robot end effector.
• Uses an air hammer and bucking bar to set the rivets instead of a c-
squeeze.
• Part will be placed in a fixture, which includes a stationary anvil and
rivet feeding system.
• Robot picks and places nut plates, as well as setting the rivets.
• Expands the range of parts to which the process may be adapted.
• Simplified version of a two robot solution where the second robot can
position and advance the bucking bar/rivet feed operation.

8. Setup
• Using a robot to locate and drill holes is a well understood operation
so our process will focus on the nut plate installation process.
• Since adding the capability to perform tool changes will add too much
scope to the project, we will be performing the drilling operation
outside of the work cell using our nut plate drill.
• Once the holes are drilled the part will be placed in a fixture that
includes the combination rivet feed/bucking bar.
• Hole alignment will be performed manually.
• This fixture will be adjustable in order to demonstrate the process in
non-horizontal orientations.

9. Proposed Process
1. Operator
places part in
robot work cell
2. On one side
rivets are fed
and block acts
as bucking bar
3. On other side,
robot places nut
plate and
hammers rivets
4. Operator
moves part to
next location

10. Proposed Process
1. Operator places part
• Operator opens the work cell door and places the part in the clamp.
• Operator makes sure that the part is in the correct orientation.
• Operator closes door for safety and to allow robot to function.
2. Rivet feed and bucking bar
Block is in contact
with part
Lines up rivet
feeder with
countersinks and
feeds rivets
Block slides
slightly to close
off rivet feeder
Block acts as
bucking bar for
impact hammer

11. Proposed Process
3. Nut plate placement and rivet hammering
4. Operator moves part to new location
Robot moves from
home position and
retrieves a nut
plate from
dispenser
Robot positions
nut plate on rivets.
Impact hammer
sets both rivets
Robot pulls off of
nut plate and
returns to home
position

12. Rivet Feed Anvil
• Rivets are
pneumatically fed
• Plate slides to act as
bucking bar for air
hammer
• Thickness of plate
matches length of
rivet so one rivet slides
within the plate

13. Robot End Effector
• Impact hammer is a place holder until
final impact hammer is selected
• Mounts will be modified once final
impact hammer dimensions are
obtained

14. Nut Plate Grabber
• Simulation of the interference fit between the grabber and
the nut plate to confirm that the grabber design should not
fail during normal operation

15. Nut Plate Dispenser
• Gravity fed
• Rails keep nut plates from over lapping
• Allows nut plate grabber to precisely
seat nut plate by pushing it against the
back wall

16. Part Frame
• Operator manually
clamps part into
place
• Able to adjust the
angle of the part

17. Complete Work Cell

18. Complete Work Cell

19. Pneumatic System
• The robot includes air lines for pneumatic control of the end effector,
but we will require additional pneumatics to operate the rivet feed
and actuate the anvil.
• Future teams will likely require additional actuation.

20. Robot Documentation
• Documentation package for future teams to get up to speed on robot
operation and programming.
• There is a huge volume of documentation for the Denso robot, and it
would be helpful to have a basic manual that includes all information
necessary to start working with the robot.
• The documentation will have the following components:
• A quick start guide that runs through the process of starting up the robot and
walks through the basics of manually operating the robot.
• A beginner’s programming guide with example code that breaks down syntax
for clarity.
• A reference guide that can point future teams to the most important/useful
section of the various robot documentation.

21. Project Timeline (Spring 2016)
Deadline Event/Milestone Additional Deliverables
2/1 CAD Drawings of Work Cell/Components Mock part design, models, drafts completed
2/19 Logbook Due
2/22 Detailed Design Review
3/8 WINCAPS Program of Robot Motions Robot motions coded based on current design. Major adjustments anticipated.
3/8 Prototypes of Work Cell Components First functional prototypes of work cell steps built and ready to test on individual basis
3/8
Design Revisions To Prototype
Components Results of prototype testing evaluated, prototype revisions considered and
3/8 Snapshot Day
3/29 Wiki Page Review
4/10 WINCAPS Programming Complete All robot motions completely coded. Further adjustments should be minor.
4/10 Final Work Cell Built All work cell components installed, Final process may be evaluated
4/20 Evaluation of Process (Results of Testing)
4/29 Design Expo
5/6 Course Deliverables Due
Final hardware/software, Design Report/Project Portfolio, Wikipage, Project Poster, Work Area
Checkout

22. Discussion
• Are you satisfied with the solution we have presented?
• Are the process steps selected for our proof of concept appropriate?
• Air hammer/nut plate grabber end effector.
• Nut plate feed device.
• Anvil/rivet feeder.
• Are there any obvious pitfalls that you would like to point out?
• Thank you for your time.