ENGR 402.

01
Introduction to Biomechatronics
Research Proposal

EXOSKELETON FOR DAILY USE

Submitted by: Kaya Uras TUZCUOĞLU (EEEN)

Project Advisor: Asst. Prof. İbrahim Başar AKA

1. Objective 2

2. Introduction 2

3. Materials & Methods 2

4. Sub Projects 3

5. Possible future work 3

6. References 4

1. Objective

1
Working with heavy objects or prolonged Exoskeleton, or an electromechanical suit, is a
activities under a heavy load leads to many wearable external device that helps a user in
medical discomforts and injuries. To address
these issues, the human dexterity and machine
power can be combined with the use of a
series of electromechanical and mechanical
compo-nents such as pneumatic artificial
muscles, actuators and microcontrollers to
create a exoskeleton, which would also have
the benefit of increase in strength and
endurance.

2. Introduction
In the history of mankind there has always Fig. 1 Robot bending the pipe with
been tools that helped us do things we could too much applied force [4]
not with our bare hands. In the prehistoric era,
there were hammers and axes made from mobility and other motor activity. It gives
stone. Later, we upgraded them to metal ones. more strength and endurance via (if powered)
To move very large objects or in farming we electric motors, pneumatics, and hydraulics
started using animals instead of man, which principles. Exoskeleton’s goal is not only to
led to more people being unoccupied to do provide support to the paralytic and
other things. handicapped indivi-duals but to also increase
With today’s technology, we can do things the physical capabi-lities of non-disabled
that would have required thousands of people people. Two main types of exoskeletons exist.
and animals with only few machinery. There Powered exoskele-tons use electric motors,
are even robots, which are designed to do tasks pneumatics, levers and hydraulics or
of humans, without needing to sleep or eat, combination of technologies to allow
with better efficiency. Yet still, there are still movement of parts. Passive exoskeletons are
jobs that require humans or at least human mostly mechanical and give less benefits to the
obser-vants, because some human touch is user. They are mostly made of soft materials.
required. As robots cannot think or feel like
we do (Fig 1.), a bridge between us and 3. Materials & Methods
machines is needed. In designing an exoskeleton, a material that is
To address this issue in the 1970s [1], the first light and strong is required to form the frame
exoskeleton was proposed and manufactured. of the exoskeleton. This is because a lighter
Even being crude and encumbering some, it frame means lesser power is required to
showed that human dexterity and machine actuate the body part. However, the frame of
power could be combined. the exoskeleton should be hard enough to
In the 1990s [2] the first lower body withstand the torque generated by the actuator
prosthetics working with microcontrollers and also the bodyweight of the wearer.
were made and in 2005[3] DARPA started its Aluminium alloys are chosen as their main
Revolutionizing Prosthetics program. Both material for the frame of the exoskeleton.
have improved and are still improving the Although different types of aluminium alloys
quality of life for people without limbs or with are used in different studies, the main reason
permanent limb dis-abilities. They also allow aluminium alloys is one of the most popular
them to be as effi-cient, or in some cases even material is because of its lightness and
more efficient than people without disabilities. strength.Aluminium 2024 and stainless steel is
Using stronger, more durable materials with used to construct the structure of the
specifications, improving the software used in exoskeleton.The duralumin is used to from the
their micro-controllers and integrating new frame andthe stainless steel is used to form the
technologies to the existing ones shall allow us joints. On the other hand, a combination of
to improve artificial limbs and electromech- aluminium alloy 7075 and polyamide 6 are
anical suits to the degree of being a must in used to form the structure of the exoskeleton.
our complex industry structure. The aluminium alloy 7075 are used in high
load structure whereas the polyamide 6 are

2
applied in low load structure to make the An alternative approach is represented by
exoskeleton as light as possible. The prosthetic Learning By Demonstration (LbD), where the
aluminium tubing is chosen because it is human subject is observed during the task
designed for human use and is very light. execution and the robotic system replicates the
Carbon fibers are only used in a small portion learnt movement. It allows avoiding motion
because it is very expensive despite the fact planning in the Cartesian space and inverse
that it is lighter than aluminium alloys. The kinematics, but it requires learning the target
yield strength of the material is very important joint configuration to be reached through
as the frame of exoskeleton needs to be strong supervised learning.
enough to actuate limbs without breaking.
Although aluminium 7068 has the highest 5. Workshare
density, the difference is not as significant as Uras Tuzcuoğlu is assigned to deal with
the yield strength. Apart from that, aluminium problems about battery and use of
7068 and 7075 has lower machinability from microcontrollers. Kinematic calculations and
aluminium 2024 which is expected from a mathematical derivations are done by Okan
harder alloy. Aluminium 7068 would be the Taşkara. Trajectory planning is done by Berk
right material to be used to form the frame of Eldem. Toygar Yazıcıoğullar deals with
an exoskeleton due to its strength despite the materials. Mughees Hussain is the head of
fact that it has the highest density and lower research and future projects.
machinability among the others. However, due
to its low availability, the aluminium 7075 6. Possible future work
with higher availability, lower yield strength We would like to look into different ways to
as well as density is chosen to be the material control the exoskeleton i.e Brain-Controlled
to form the exoskeleton in this project. System, A.I controlled System, Haptic-Feed-
back System, etcWe can try to find other
4. Sub Projects applications of the exoskeleton in our every-
Understanding trajectory planning in human day lives and modify the design accordingly.
movements plays a huge role in upper-limb Currently, the external power source is
exoskeletons for rehabilitation and assistive limiting the design and we would like to
purposes because of the close physical human- remedy that with suitable alternatives.
robot interaction. A typical strategy for
determining the desired trajectory to be
tracked by the exoskeleton in complex tasks,
such as the Activities of Daily Living (ADLs),
is to replicate human movements. Joint
trajectories from volunteers, caregivers, or
therapists can be pre-recorded and later
executed by the robotic system throughout
specific mapping methods.
For ADLs in an unstructured environment, a
Cartesian motion planner can be conveniently
adopted and a purposely developed
mathematical model of human motor behavior
should be formulated in order to plan the
desired trajectories in a way similar to
humans. For the exoskeletons, the approach
based on Cartesian motion planning requires
inverse kinematics. The traditional IK
algorithm with inverse Jacobian allows
exploiting the available DoFs of the robot
kinematic chain to achieve the desired end-
effector pose; however, it does not guarantee
that the whole human-robot workspace is
satisfied.

3
6. References

[1] M. K. Vukobratovic, “WHEN WERE ACTIVE EXOSKELETONS ACTUALLY BORN?”,

[2] S. Kirker, S. Keymer, J. Talbot, S. Lachmann, “An assessment of the intelligent knee prosthesis”,
Clinical Rehabilitation, Aug. 1996. [DOI: 10.1177/026921559601000314]

[3] A. Emondi, “Revolutionizing Prosthetics”, Defense Advanced Research Projects Agency, 2005.
[Online] Available: https://www.darpa.mil/program/revolutionizing-prosthetics [Accessed Nov. 2,
2020]

[4] General Electrics, “Do You Even Lift, Bro? Hardiman Was GE's Muscular Take on the Human-
Machine Interface”, General Electrics, Aug. 25, 2016 [Online] Available: https://www.ge.com/news/
reports/ do-you-even-lift-bro-hardiman-and-the-human-machine-interface [Accessed Nov. 2, 2020]