Tony Cheang created several projects related to mechanical design, medical devices, architecture, and photography. For his medical device design class, he worked on a soft exosuit to help Parkinson's patients passively walk through doorways. For his transformations architecture class, he iterated on models using different materials to represent concepts like packing and funneling people through a space. And for his photography class, he learned techniques and created a final project on being alone in urban environments, incorporating both street photos and self-portraits.

1. 1
Harvard College
Engineering Sciences: Mechanical and Materials
115 Thrift St, San Francisco CA
cheangytony@gmail.com
415 370 9860
Tony Cheang
PORTFOLIO

2. Actuation UnitDoorway Detection
Textile Interface
Overview of the system
3SOFT EXOSUIT FOR PARKINSON’S
In this four-person, twelve week project, we sought to aid patients with Parkinson’s
Disease, a neurodegenerative disorder that leads to muscular atrophy.
To find our area innovation, we reviewed medical literature on the disease, met
with clinicians, and examined the body of existing devices for the first four weeks.
We decided to address freezing of gait, a symptom where patients abruptly take
shorter and shorter steps until stopping for a few seconds. Current devices require
too much attention from the user and only prevent up to 80% of freezes.
The next two weeks of ideating led to discovering our space of innovation: me-
chanical cueing with a low-profile soft exosuit that detects and responds to en-
vironments which typically trigger freezing of gait. For our final prototype, we
decided to address the classical “doorway freeze”.
Weeks seven to ten were spent building our device. Specifically, I designed the in-
terface between the doorway and the physical suit: wiring our motors to the motor
controller and Arduino Due, and implementing the PID motor control.
During week eleven, we tested the exosuit to ensure robustness under a variety of
gait lengths and cadences. The last week, we prepared and rehearsed a twenty-five
minute presentation to an audience of fifty.
ES227: Medical Device Design, Instructor Conor Walsh, Spring 2015
SOFT EXOSKELETON
FOR PARKINSON’S PATIENTS

3. RFID
Reader
Arduino
XBee
1
3
2
Torque
r
The suit acts as a spring parallel to the leg
The suit at 0%, 50%, and 100% of the gait cycle
Suit activation as the user approaches the doorway
SOFT EXOSUIT FOR PARKINSON’S 5
The suit aids the user passively by ex-
ploiting the rising and falling of the us-
er’s center of mass while walking.
You can think of the leg as a spring that
contracts when a walker moves his cen-
ter of mass over the leg. It releases its
energy when the leg is behind the walk-
er, powering the “push-off” stage of
walking. While the suit is active, it acts
as a spring in parallel with the leg, in-
creasing the leg-spring systems’s spring
coefficient, allowing it to store more en-
ergy per cycle.
The suit only becomes taut as each leg
moves behind the walker, right before
the push-off stage. This synchronized
activation prevents the suit from inter-
fering with any other part of the gait
cycle.
1) The RFID on the user signals the
RFID reader on the wall next to the door,
and the reader sends a signal to the Ar-
duino XBee wireless communicator.
2) The XBee on the wall communicates
with the actuation unit on the user’s
back, confirming that there’s a doorway
ahead.
3) The motors turn to retract two bowden
cables, contracting the suit and activat-
ing the timer-based passive assistance
through the doorway.
4) Once the user is through the door-
way, the motors reset the cable position,
slackening the suit until another high
risk situation.

4. Two prototypes and the final product
We used a treadmill to keep our tester walking at a constant pace
Load cells placed on the hips and the ankles measure retraction and force
SOFT EXOSKELETON FOR PARKINSON’S 7
To ensure our device would provide the
target 5% of the user’s ankle torque, we
measured the force at the ankle and mul-
tiplied by the distance to the joint.
While we found that gait speed margin-
ally affects the performance of the de-
vice at a constant retraction, step length
variation affected the performance much
more. This can be solved by increasing
the bowden cables’ retraction, thereby
tightening the suit more..
The next step would be to add gait-feed-
back that accounts for step length varia-
tion. From there, other high risk scenar-
ios--crowded spaces, sharp turns--could
be targeted.

5. Funneling is made of three materials: acrylic, cardstock, and bass wood
9TRANSFORMATIONS
In this twelve week class taught at Harvard’s graduate school of design, I iterated on
the initial operational concept of “packing” cubes to create a multi-material model
situated to a specific site: Longfellow Park in Cambridge, Massachusetts. Concepts
from each successive project trickle down to add spatial and logical complexity.
At the beginning of the first seven weeks, I hand-cut cardstock to create eight mod-
els representing various operations (e.g. weaving, packing, aggregating). I then
chose my Packing model to create Pattern, a rotational, logic-driven pattern from
which an acrylic, laser-cut, and hand-assembled model was created. A cross-sec-
tional plane technique was then used to create Intensity, a chipboard model with
varying densities that highlight the logic in the structure. Removing extraneous
walls and boxes while connecting the remaining material yielded Volume.
The next five weeks, I tested techniques for hybridizing materials, analyzed my
physical site, and built the final model. I analyzed my site’s topographic tendency to
direct people to the southern part of the park (funneling). This then informed how I
would use differential material to guide people through my final, spiral-like model.
Digital models were created in Rhino, from which drawings were exported and
edited in Adobe Illustrator. Laser cutters were used extensively to cut surfaces, but
assembly was all done by hand using tasteful amounts of glue and plastruct.
HAA96a: Transformations, Instructor Megan Panzano, Spring 2016
TRANSFORMATIONS:
ARCHITECTURAL ITERATION

6. Cardstock model of Packing
Acrylic model of Pattern
Cross sectional planes model of part of Intensity
Cardstock model of Volume
TRANSFORMATIONS 11
The initial operational concept of pack-
ing was created in contrast to aggregat-
ing: while aggregating is the unbounded
coming together of material, packing is
the fitting of material into a container of
fixed size. Packing, a cube containing
various sized smaller cubes became the
basis for Pattern.
In Pattern, a set of instructions gives
rise to the final form. Layers within the
cube rotate clockwise and counterclock-
wise in each successive step. Each step
then generates a new cube that is placed
in a counterclockwise spiral motion next
to prior cubes. When four cubes com-
plete a box, the pattern propagates both
upward and outward.
The final 3d model of Patterns contains
thirteen steps of this logic, but only two
cubes were created to save time.
Propagating the spiral both upward and
outward (when the central four cubes on
each floor complete a square) results in
a central column that contains all cubes
necessary to reproduce the planar spirals
on each floor: a DNA of the structure.
To highlight the intensity of informa-
tion in the central column, the density
of planes in Intensity was increased for
the central four boxes, and decreased for
the outer boxes. This density difference
is shown along the bottom left to upper
right diagonal of the model above.
Preserving the logic of the thirteen steps
required only that I keep the most agi-
tated cube from my model. Joining those
with a ribbon in the x-y and highlighting
interior-exterior interplay with sectional
addition created Volume.

7. -5'
70'
100'
0"
6"
25'
Elevation map of Longfellow Park showcasing “funneling”
Density diagram of the spatial-junction-connected spaces
View of a spatial-junction in Volume
13TRANSFORMATIONS
I extensively surveyed the heights of the
buildings and the elevation changes in
the surrounding block before plotting
the above diagrams in Rhino and export-
ing to Illustrator.
I decided to situate my final model, Fun-
neling, at the junction between the north
and south portions of the park, where
there’s a half-story elevation change.

8. 10’
TONY CHEANG
TRANSFORMATIONS
SPRING 2016
1
2
10’
TONY CHEANG
TRANSFORMATIONS
SPRING 2016
1
10’
2
Differential material leads people through the structure
The basswood acts as the two ground datums Diagrams with ground datums showing elevation change between north and south
TRANSFORMATIONS 15
Placed at the junction of north and south,
Funneling acts as an elevation mediator.
The decision to put glass for the outer
cubes of the second floor but concrete
for the center rooms guides the user to
the center of the spiral using a concept
of differential material, similar to how
light bends across materials. This is
reversed on the first floor; the center is
glass while the edge cubes are concrete.
A person walking in the second floor
would be guided down and out with
glass always on their left side and con-
crete always on their right. Conceptu-
ally, this might be fitting as a school for
the blind.
The model is a 1:8 scale model. Each
cubic room would offer 100 square feet
of space.

9. Tokyo Intersection from ‘Light’ assignment
17PHOTOGRAPHY
This class served as an in-depth introduction to thinking about and creating pho-
tographic art. Studio time was spent analyzing famous photographs and bodies of
work, and critiquing the bimonthly works of fellow students. From this, I learned
the basics of composition, color, lighting, and subject matter.
Workshops were conducted outside of studio time to learn printing and photo edit-
ing techniques like white balancing, masking, and split toning in Adobe Photoshop.
The class culminated in a month-long final project, where I chose to address the
concept of “being alone.” The final deliverable was twelve 16” x 12” prints.
After the conclusion of the class, I purchased my own equipment, and continued
to photograph. Since I no longer had access to a photo studio equipped with color
calibrated monitors and high quality printers, I decided to research the important
elements of color-accurate workflow and set up a small workspace for myself. For
photographing events, I also learned Adobe Lightroom for quicker processing.
While some of my best work so far has come from travel and dance events, I am
currently wrestling with how to photograph more familiar locations such as my
hometown San Francisco. I also look forward to applying these skills at my next
workplace for documentation, presentations, and the creation of other visual ma-
terials.
VES41a: Intro to Photography, Instructor Sharon Harper, Spring 2016
PHOTOGRAPHY

10. Mother and Daughter from ‘Alone’ Passersby from ‘Alone’
PHOTOGRAPHY 19
‘Alone’, comprised of twelve images,
deals with conceptions of being alone in
urban environments.
‘Mother and Daughter’ distances the
viewer from the two subjects, allowing
the tunnel to create a sense of isolation
from their togetherness. ‘Passersby’
deals with how despite high populations,
people can still feel alone in cities.

11. Street photo from ‘Alone’
Response photo from ‘Alone’
PHOTOGRAPHY 21
After taking some of the street photos, I
went out and created corresponding im-
ages by photographing myself in fitting
environments. In this way, ‘Alone’ also
incorporates how I respond to others be-
ing alone.
This method extends the feeling of being
alone to more than the loneliness depict-
ed in the two photos before this; it can
also be quiet, contemplative, peaceful.

12. Asian American Dance Troupe: Solidarity
Ballroom Dancers: Vulnerability
PHOTOGRAPHY 21
As a dancer myself, I use my sense of
rhythm and music to anticipate danc-
ers’ movements and figures. While pho-
tographing, I look for moments with
meaning beyond just dancing.

13. Morning over Tokyo (Tokyo)
Migrant Dreams (New York)
23PHOTOGRAPHY
Some of my favorite photographs have
been made during travels with friends.
In ‘Morning over Tokyo’, a friend
checks whether his laundry has dried.
The condensation on the left captures the
chilly March mornings of Tokyo, while
the bright sun still feels weak. ‘Migrant
Dreams’ shows a boy of color looking
away from the majestic statue of liberty,
while gripping the boat’s railing tightly.