1. Introduction

1.1 Problem Statement:
After people break their arms and their cast is removed, they spend thousands of dollars on physiotherapy but also this comes with the consequence of not being able to do normal work such as lifting things etc. Thus, we are building this exoskeleton to help with physiotherapy as an exoskeleton would let the patient/recovering person do. The long bone of the upper arm is known as the humerus. (PhysioAdvisor.com., 2014)Small fractures of the forearm heal in about four weeks when immobilized in a cast. More severe forearm fractures may need to be repaired surgically, and then immobilized for up to 12 weeks.(Orthopaedic Trauma Association, National Institute of Arthritis and Musculoskeletal and Skin Diseases, & National Rehabilitation Information Center 
(NARIC)., 2013)
Relevant Anatomy for a Humeral Fracture

PhysioAdvisor.com. (Designer). (2014, May 19). Figure 1-
Relevant Anatomy for a Humeral Fracture [Web Photo]. 
Retrieved from 
http://www.physioadvisor.com.au/14987050/humeral-fracture-physioadvisor.htm

1.2 Engineering Goals:

We hope to enable people with weak arms who are undergoing  physiotherapy recover faster by helping them with regaining their movements. It will be able to do basic activities. It shall be lightweight due to the fact that it is going to be used for the whole day. This will make it more help the weak by making their weak arm to more useful activities.
1.3 Specifications:
Using a Servo to help ease the movement by a 1 is to 5 ratio ( 1° moved by user = 5°)

1.4 Alternative Solutions
1.4.1:
Using a piston mechanism to operate the arm. (instead of servos)
A piston can easily replace and take over the capabilities of a servo. A piston can easily overcome the huge moment forces needed to move the exo arm.
1.4.2:
Using a button to operate and control the movement of the arm.
A button is easier to use and has more flexibility in control. It is also easier to be made due to just a button not a sensor.The button mechanism is still programmed using Arduino just that the code is different as each button may represent a degree.
1.4.3:
Using the fingers to make the servo move/rotate.
It is a usually a no choice scenario that if we can’t do anything about it and we just make it this way.

1.4.4:Best Solution and Reason
Our best solution was the servomechanism. The servo first and to be properly programmed and it was the easiest to make the forearm turn according to the programmed degree. It was also the easier one to use as it had a 180˚ capability which was compatible to an ordinary human arm’s capability and also was easier to fix compared to the piston mechanism.


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