User:Youssef Walid/sandbox

The Superbs Team members:  Youssef Walid, Mostafa Hazem, Mohammed Akram, Tariq Mohammed and Bahaa Shalakany Purpose: Documenting the project progress and Details, The way of thinking and strategy and Implementations

Overview

The first step that we took into determining which field will the project be about is a research on each topic, every team member had to do a research on 3 of the subjects. Step 2 was for everyone to read the reports and an election phase was executed. The result of this phase was that we decided to start a Prosthetic hand project. Now that the idea was agreed upon, tasks were to be assigned accordingly to the team members, the result was as follows: Tariq: Mechanical Design Mostafa: Electrical Design Mohammed: Co-Electrical Bahaa: Co-Mechanical Youssef: Documentation We work together, make reports, find videos of past projects and gather Ideas until we reach the phase of buying and integrating the final product.

Samples of the researches as for links:

1.	https://www.youtube.com/watch?v=uWL13vvi94s

2.	https://www.youtube.com/watch?v=Al5RhaJgxxU

3.	https://pdfs.semanticscholar.org/a6f4/a43d1c5e344db13997eb6ea62d30ead0efdf.pdf

4.	https://www.youtube.com/watch?v=WQlzt7uLi0k&list=PL8E1323BBD86C3FE4&index=9

5.	http://smpp.northwestern.edu/downloads/Design%20Of%20Artificial%20Arms%20And%20Hands%20For%20Prosthetic%20Applications.pdf

6.	https://www.youtube.com/watch?v=tLyRJc87KDY&list=PL8E1323BBD86C3FE4&index=4

Detailed Documentations

THE NATURE OF THE PROBLEM:

There are over 30 muscles acting on the forearm and hand. The human hand has 27 major bones, and at least 18 joint articulations with 27 or more (DOF). The arm contributes another 7 degrees of freedom. The primary role of the arm is to position the hand in space. The primary role of the hand is to enable a person to interact with the environment. Control of a person’s arm is directed at controlling the position of the arm’s hand. Even though people control their arms with great facility, this is a highly complex and demanding task. A backhoe is essentially a mechanical arm that is under the control of an operator. To control a mechanical arm the operator uses both arms, both feet, both eyes, and all his or her concentration.

GENERAL DESIGN CONSIDERATIONS:

Shape & function

The role of form, or cosmetics, in prosthetics cannot be overstated. Often the design team will sacrifice cosmetic appeal to achieve increased prehensile function. However, the relative importance of appearance versus function is highly dependent on the person with the amputation. Some people may be solely concerned with visual presentation and reject a highly functional body-powered, cable-operated prosthesis because of the unacceptable appearance of the control harness or of a hook-shaped terminal device. Others might find the function provided by these devices sufficient to outweigh their concerns about their appearance. Still others prefer a more tool-like appearance believing a prosthesis that looks like a natural arm or hand but is not is a deception.

Weight

Final weight of a prosthesis is critical to the success of any prosthetic fitting. Contrary to what one might think, one should not make an artificial limb replacement the same weight as the limb it replaces. The weight of an adult male arm is about 10 kg (20 lb). Total arm replacements that exceed 3.5 kg (~7.5 lb) cannot be expected to be worn and used for a full day because of the discomfort associated with suspending that much weight from the body. Artificial arms need to be as light as possible or else they will end up in a closet. The lack of an intimate connection between amputee and limb replacement means that the prosthesis is perceived as an external load and therefore as something that must be carried. To be effective, artificial arms should be worn by their users for periods more than 8 to 12 hours a day. To gain some insight into how this might feel, consider carrying a 6-lb laptop computer slung from your shoulder for a day.

Power Sources:

As is the case for all portable devices, power is scarce. Choice of power source defines a prosthesis; in that it determines the choice of actuator. If the power source is to be the person, i.e., body power, then the actuator is the person’s own musculature and the prosthesis should not require excessive effort to use. Mechanical mechanisms need to be efficient and frictional losses need to be minimized to avoid tiring the user over the course of a day. If the artificial limb is externally powered (i.e., uses a power source other than the body, usually electric storage), the limb should be able to run for a day from the same power source without needing to be replaced or recharged. In addition, it is desirable for the power source to be contained within the prosthesis. Electrochemical batteries are the main source of energy for modern externally powered prosthetic arms, although pneumatic gas cylinders have been used in the past. There are a number of other technologies that could replace batteries as portable sources of electricity in the future. These include electromechanical flywheel systems that store energy in a rotating disk, and miniature Wankel type rotary combustion engines. However the most promising technology is that of ethanol- or methanolbased fuel cells. These devices are already moving into production for interim cell phone products. All are heavy and occupy excessive space. If electricity is the power source, then for the foreseeable future, dc electric motors will be the actuators.

DC Electric Motors:

By far the most common actuator for electrically powered prostheses is the permanent magnet dc electric motor with some form of transmission. While there is much research into other electrically powered actuator technologies, such as shape memory alloys and electroactive polymers, none is to the point where it can compete against the dc electric motor. For electrically powered prosthetic hand mechanisms, a coreless, or ironless, dc motor with a fitted gear head transmission is the actuator of choice. For elbows, coreless dc motors, or brushless dc motors and a transmission are used. Brushless dc motors are becoming more common now that both the motor and its electronics are small enough to be accommodated in a prosthetic elbow (they are still too large for hand mechanisms, but this is likely to change). Although brushless motors require much more complicated control electronics, their use is justified because they have substantially higher performance than their coreless counterparts. In addition, recent advances in surface mounted integrated circuit (IC) technology greatly facilitate the design of controllers for these motors. A broad range of driver and controller ICs are available in surface-mount forms from companies like Texas Instruments, International Rectifier, ST Electronics, Vishay-Siliconix, Zetex, among others, and application notes explaining the use of these chips are readily available on company Web pages.

These are some points of the detailed Documentations that are yet progress.