Kevin Lomeli restored a clunker car as a teenager, sparking his interest in mechanical engineering. In college, he worked on several engineering projects including designing a drink dispensing fridge called the Beverator. He also worked on a virtual path simulator and steering technology projects. After graduating, he assisted UC Berkeley research groups by designing camera mounts for small aircraft and UAV server racks. He has experience in mechanical design, product development, control systems, and unmanned aircraft technology.

1. KEVIN LOMELI
Mechanical Engineer
Early Day &
Undergraduate
Portfolio
photos taken by Kevin Lomeli
all rights reserved

2. At 14, I found a clunker and turned it into a usable ride
I restored the car from the inside out. This sparked my interest to pursue engineering in college.

3. THE BEVERATOR
PRODUCT DEVELOPMENT, UC BERKELEY
FALL 2007

4. Initial
Concept
Sketches
Door
Hinge Sliding
Door
Drink dispensing fridge for home use
 Miguel'Christophy'
 Kevin'Lomeli' Drawer
Option
 Jahon'Khorsandi'
Dispensing
Mechanism
Product Development, UC Berkeley, Fall 2007
Round
or
Flat
Front

5. Final
Design
and
Functionality
Polycarbonate containers with Magnetic display with whiteboard
removable nozzles functionality
ball bearing locks into place upon
sliding for easy container removal
Easy-glide rails with insulating
Bottom drawer with can rack rubber
holds 4.5 US Gal. or up to 14 cans.
Standard mini fridge cooling
system
Magnetic studs for catch drain
make clean up a breeze

6. The success of this project
was a result of the following:
• Group collaboration &
brainstorming sessions
• Mission statement and proposal
• Gantt chart & task assignments
• Financial analysis
• Technical specifications and
requirements
• Product portfolio
• Material selection, manufacturing
process, & bill of materials
• Engineering drawings via
SolidWorks
• CAD rendition & animation
• Technical report

7. THE VIRTUAL PATH
SIMULATOR
SENIOR MECHATRONICS, UC BERKELEY
SPRING 2008

8. Virtual Path Simulator
Objective: Guide the user’s hand along a specified two-dimensional path to reach a
desired final position.
Motivation: Guide physical motion without the aid of visual feedback.
Key Design Factors:
• easure the user’s free movement in the forward direction (Green Arrows)
M
• alculate the desired horizontal position (Red Path)
C
• pply torque via motor control to move the hand to the desired position (Blue Arrows)
A

9. Virtual Path Simulator
Mechanical Description
DC Motor & Gear Box Pulley (x2) Slide Rail (x2) Encoder
(Lateral Position)
Timing Belt
Hand Strap
Encoder
(Forward Position) Control Panel DSP
(Path Options)

10. Virtual Path Simulator
Control Algorithm Ymeas Lateral
Encoder
Forward Xmeas f(x) Ydes e Controller Plant
X Encoder (Path) (DSP) (Motor)
Yact
X
Y = f(x)

11. SENIOR YEAR & POST GRADUATION
I assisted some of Berkeley’s
renowned research groups

12. SENSOR TECHNOLOGY
UNDERGRAD RESEARCH, UC BERKELEY
FALL 2008 - SPRING 2009

13. Sensor Technology
EXPLOSIVES (DNT) DETECTION
As humid air and DNT pass over a quartz crystal, the crystal vibrates with varying
frequency.
If DNT sticks to the sensor and changes the sensor’s natural frequency by ~10X of its
standard deviation, then detection is successful...

14. Sensor Technology
RESULTS
Humidity Effect Temperature Effect
The interaction between humidity and temperature drastically changed the sensor’s
frequency. Due to the presence of humidity, the resulting frequency readings were
non-repeatable. As a result, the detection requirement was not met.
Next, we took a different approach. We redesigned
the test apparatus using two sensors, with one of
the two sensors as a reference.

15. SENSOR TECHNOLOGY
Redesigned the explosives-
detection test environment
w
ir flo
a
•
• Air-tight seal
Assistantship ended
• Well distributed airflow
before I could build a
• Improved signal
prototype

16. STEERING TECHNOLOGY
UNDERGRAD RESEARCH, UC BERKELEY
ALSO FALL 2008 - SPRING 2009

17. STEERING TECHNOLOGY
HUMANS & DRIVING
Modeled the dynamic response of human arms gripping a steering wheel.
Why?
A human model is extremely useful for designing a reliable electronic power steering (EPS) controller.

18. STEERING TECHNOLOGY
SYSTEM ID
!
Measured Torque to Wheel Speed: !
Wheel Torque to Wheel Speed: !
Wheel Speed to Input Torque: !
Estimated Wheel Speed to Input Torque: !

19. STEERING TECHNOLOGY
METHOD
• Measured steering wheel speed and input torque
• Curve fitted frequency response data using least squares regression
• Averaged the response from different hand to steering wheel postures
RESULTS
!
!
!
This model can now be utilized for future research and controller design.

20. STEERING TECHNOLOGY
Steer by Wire
One steering wheel. One motorized rack & pinion.
No steering shaft.

21. Steering Technology
System ID
The model is a 2nd order transfer function of torque input (N) to angular position (rad). The
model includes armature inertia (Jm), viscous friction (B), and time delay (Td).
The following are the results from using system ID techniques:
! !

22. Steering Technology
Control Approach
Implemented a real-time controller with velocity and position feedback using lead-lag compensators
and notch filters.
This is the detailed feedback model:
C*C_notch
H*C_LPF
Utilized classical control theory. Simulation conducted in Matlab & Excel.

23. Steering Technology
Analysis
These are the results of the first controller in simulation:
Step response: ~20% OS & 0.2s settling time. Position error with sinusoidal input
Results were stable and robust, so I implemented the control in real
time.

24. Steering Technology
Real Time Control
Tuned gains based on step and sinusoidal input responses.
Blue: Large loop gain Green: large loop gain
(Good tracking & disturbance rejection) (Good tracking & disturbance rejection)
Green: Not as much as blue Blue: Not as much as green
Tuning yielded a reliable controller with 20%OS and a 0.8 rad error. This is the final controller
for the steer by wire system:

25. UNMANNED AIRCRAFT
TECHNOLOGY
UNDERGRAD DESIGN ENGINEERING
ALSO FALL 2008 - SPRING 2009

26. ITEM NO. PART NUMBER DESCRIPTION QTY.
1 back_plate BackPlate 1 ITEM
25.50
Note:
1) #8-32 Threaded through 2 side1 Side Plate 1 1 6 NO.
PART NAME DESCRIPTION QTY.
spaced 1" apart from
each other.
3
4
side2
stud
Side Plate 2
Press-In Stud
1
1 9 1 Rear Wheel Spindle Machined Part 1
#6-32 Allen Head Machine
2) Weld Corners and 5 #6_Screw 4 2 Rear Wheel Rim Available in Lab 2
crossmembers.
Screw
5
Unmanned Aircraft Technology
3 Rear Wheel Bearing Block Machined Part 1
8.50
McMaster-Carr
12.00 12.00 2 4 Rear Wheel Bearing
PN: 2780T56
1
4 5 Rear Wheel Spacer Machined Part 1
6 GR 8 Hex Nylon-Insert 7/16- McMaster-Carr 1
20 LockNut PN: 97135A245
9.00
7 Rear Wheel 1
7 8
GR 8 Alloy Steel Hex Head McMaster-Carr
1
1.00
8.00 8.00 8.00 Cap Screw 1/4 - 20 x 1inch PN: 92620A542
9 Socket Cap Hex 4-40 3/4 in 6
3 10 Hex NylonSteel #4 Stainless
Locknut 6
U
HR
6.50
6T McMaster-Carr
Designed and Built Thermal & Video Camera Mounts for
0.1 11 Rear Wheel Washer 1
PN: 91083A013
10 Note 1: When assembling the bearing and the bearing block, make sure
2 that the side of the bearing block with wall is facing the spindle, facing
away from the side with the GR 8 Hex Locknut (Item No. 6).
0.50
Note 2: Although not shown, there are 7/16-20 threads on the Spindle
1
UNLESS OTHERWISE SPECIFIED: NAME
UNLESS OTHERWISE SPECIFIED: NAME DATE DATE
(Item No. 1) that matches the hex nut (Item No. 6). The thread length is
Kevin
Kevin 3/10/09 DIMENSIONS ARE IN INCHES DRAWN 4/11/09
specified in the drawing for the RearWheelSpindle.
11
DIMENSIONS ARE IN INCHES DRAWN
TOLERANCES:
TOLERANCES:
FRACTIONAL CHECKED TITLE: BAT Payload Rack FRACTIONAL CHECKED TITLE: Camera Mount Assembly
Unmanned Aircraft
ANGULAR: MACH BEND ANGULAR: MACH BEND NAME DATE
C3UV
ENG APPR. ENG APPR. DIMENSIONS ARE IN INCHES
TWO PLACE DECIMAL TWO PLACE DECIMAL
TOLERANCES: DRAWN
THREE PLACE DECIMAL THREE PLACE DECIMAL MFG APPR.
MFG APPR. FRACTIONAL
CHECKED
ANGULAR: MACH BEND
INTERPRET GEOMETRIC Q.A. INTERPRET GEOMETRIC Q.A.
PROPRIETARY AND CONFIDENTIAL TWO PLACE DECIMAL ENG APPR.
PROPRIETARY AND CONFIDENTIAL TOLERANCING PER: TOLERANCING PER:
COMMENTS: Press fit stud into hole THREE PLACE DECIMAL
Rear Wheel Assembly
COMMENTS: MFG APPR.
THE INFORMATION CONTAINED IN THIS MATERIAL PROPRIETARY AND CONFIDENTIAL
THE INFORMATION CONTAINED IN THIS MATERIAL
SIZE DWG. NO. REV 50 Series Aluminum
SIZE DWG. NO. REV
A Assem1
DRAWING IS THE SOLE PROPERTY OF
A
DRAWING IS THE SOLE PROPERTY OF 0.5"X0.5"X.125" L-Shape 6063-T52 AL THE INFORMATION CONTAINED IN THIS MATERIAL Q.A.
Payload Rack Rev3 <INSERT COMPANY NAME HERE>. ANY --
8
<INSERT COMPANY NAME HERE>. ANY DRAWING IS THE SOLE PROPERTY OF
REPRODUCTION IN PART OR AS A WHOLE FINISH: File abrasions from welding REPRODUCTION IN PART OR AS A WHOLE FINISH COMMENTS:
<INSERT COMPANY NAME HERE>. ANY
WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON WITHOUT THE WRITTEN PERMISSION OF NEXT ASSY USED ON round edges and burrs REPRODUCTION IN PART OR AS A WHOLE FINISH
<INSERT COMPANY NAME HERE> IS <INSERT COMPANY NAME HERE> IS WITHOUT THE WRITTEN PERMISSION OF
NEXT ASSY USED ON -- SIZE DWG. NO. REV.
PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:10 WEIGHT: SHEET 1 OF 1 PROHIBITED. APPLICATION DO NOT SCALE DRAWING SCALE: 1:5 WEIGHT: SHEET 1 OF 1 <INSERT COMPANY NAME HERE> IS A
PROHIBITED. APPLICATION DO NOT SCALE DRAWING
SCALE:1:10 SHEET 2 OF 2
5 4 3 2 1 5 4 3 2 1
WEIGHT:
1080p 40x zoom video cameras mounted
to small aircrafts. (Right-Top Pic)
The camera mount on aircraft shown
holds both thermal and video cameras.

27. UNMANNED AIRCRAFT TECHNOLOGY
Designed, machined, and
installed UAV server racks
A crash turned the first prototype into an art piece

28. CONCEPT DESIGN
I created many initial concepts for the research group. One of them is a compact & mobile UAV
engine starter. It’s purpose is to to start any scaled unmanned aircraft with variable propellor
heights.