Research in developing Robotic Sanding.

1. Goals
Summary
HawgScuff Progress Report
HawgScuff
Mark Center
University of Arkansas
Sanding Evaluation
Mark Center HawgScuff Progress Report

2. Goals
Results
Summary
Goals
Progress
Size end effector
Need full torque curve of target motor for comparison
0.75 Hp seems sufficient
Evaluate production parameters
Speed S Rev , feed-rate f min , and Depth of Cut d in
min
in
Sanding Action
Flat Surfaces
Contoured Surfaces
Protrusions
f S
r
θ
x1 x2 d
lc
Mark Center HawgScuff Progress Report

3. Goals
Results
Summary
Challenges
2 axis control, with provision for expansion
Data Acquisition
Integration
Develop Model
Verify Model
Make Recommendations
Mark Center HawgScuff Progress Report

4. Goals
Results
Summary
Control
LinuxCNC
Real-Time control
Standard RS-274NGC ( G & M codes)
Open source, open code
Active Community, very quick response for help
Expandable, configurable, reliable, robust
5i25
Real-time motion 7i77
control
Up to 6 servos
FPGA,
32 isolated 5-32V
programmable for a
inputs
variety of IO tasks
16 isolated 5-32V
Can use two
300 mA outputs
breakouts like the
7i77
Mark Center HawgScuff Progress Report

5. Goals
Results
Summary
Data Acquisition
Needed A/D to read Hp on Spindle Drive
Arduino microcontroller card
Python program PC to read Arduino and LinuxCNC
Record values into spreadsheet
Motor speed 3 S 2
x position (in)
y position (in)
time elapsed (sec)
Spindle Motor relative hp
Mark Center HawgScuff Progress Report

6. Goals
Results
Summary
Integration
PC
Spreadsheet
LinuxCNC X&Y
5i25 7i77
Drives
Python
Program Spindle
Drive
Arduino
Python to control Arduino and write Spreadsheet
"Processing" language (like C) to program Arduino
RS-274 to interact with Python and control machine
HAL to connect LinuxCNC to Python
Mark Center HawgScuff Progress Report

7. Goals
Results
Summary
Sanding Action
µ ∼ Force against surface × Distance abrasive travels
Sanding Action relation
2r arccos( r −d )
µ ∼ hpm × r
f
Contour of hp function
hpm = (A(S − B)4 + C)Sd 3 + DS 3 + E
Current model
hpm =(1.9714 × 10−15 (S − 544.06)4 + (1.0988 × 10−4 )Sd 3
+ 6.0776 × 10−8 S 3 + 1.331 × 10−2
Mark Center HawgScuff Progress Report

8. Goals
Results
Summary
(graphics/meshlab/ubfit.u3d)
Mark Center HawgScuff Progress Report

9. Goals
Results
Summary
1.6
1.4
Touch off Distance (Inches)
1.2
1
0.8
0.6
0.4
0.2
0
0 1000 2000 3000 4000
Motor Speed (RPM)
Figure: Free-running change of length by speed.
Mark Center HawgScuff Progress Report

10. Goals
Summary
Summary
We have 2 axis control with Data Aquisition
We have a working model, but it needs refinement.
Need model with Open loop spindle drive.
Have Closed loop for Sanding action comparison.
Each subsequent trial adds data for the model.
Need closer estimation of maximum sanding action.
Add third axis for evaluation of contoured surfaces
Develop test rig for Wheel life (testing done elsewhere)
Mark Center HawgScuff Progress Report