TECHNICAL PROJECT FINAL REPORT FOR ET 493 SENIOR DESIGN 1

PROJECT TITLE:3D Robotic Hand Continuation

Southeastern Louisiana UniversityDepartment of Computer Sciences and Industrial Technology

Submission date: December 2, 2016-FALL

BY: Jace Babin, Andrew Brouillette, Bach Nguyen, Bryce Schell, and Alex Stein

ET 493 SENIOR DESIGN 1-INTERIM REPORTInstructor: Dr. Cris KoutsougerasAdvisor: Dr. Cris Koutsougeras

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TABLE OF CONTENTS

1. Table of Contents…………………………………………………………………...….…1

2. Abstract………………………………………………………………………...................2

3. Introduction……………………………………………………………...………….….…3

4. Current Status……………………………….…………………………...………….….…4

5. Issues & Progress……………………………………………………………….………...6

6. Peronal Progress………………………………………………………………………......7

7. References……………………………………………………………...…....……....…...22

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ABSTRACT

This project is a continuation of a previous senior project that was worked on by David

Cothell, Chad Newberry, and Steven Walker under the supervision of Dr. Koutsougeras. The

goal of the current project is to complete the mechanical limb that is functional to be able to

mimic the movement of the human hand. The hand was designed in Solidworks, and because the

last physical design was only a proof of concept, there is room for improvement in the design.

The whole hand will be redesigned in SolidWorks to a better standard which allows a more

visual look, along with better functionality and a greater degree of freedom for the fingers to

allow for a more natural movement. When it’s complete, this device is expected to mimic the

human hand. This is done by the articulate, function, operation, and response through a series of

actuators, motors, and servos. The control of this arm will be controlled remotely by a capable

user either through VR, real time in a containment chamber or through a camera that is mounted

on the body of the robot. There will be a revisit on the materials (PLA and ABS plastic), a resize

and a redesign of the hand that will be fabricated in SolidWorks (3D modeling software) and use

of the university’s 3D printer to reconstruct the remodeled parts of the project. The main priority

will be the hand and glove functionality and communication with each other, as well as having a

finished robotic hand that completely improves upon all aspects of the previous hand. If the

deliverables have been finished with additional time to work on the project, the construction of

the arm and a wrist will be attempted. Attaching an arm on the hand will provide additional

movements for the location and rotation of the hand.

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INTRODUCTION

There is a remote location that has been put under a quarantine zone due to a highly

contagious Ebola virus. These people will require supplies and medicines in this quarantine zone.

Sometimes a real person has come into close contact to do all of these intricate tasks, putting

themselves in danger of contamination. The design of this robotic hand mechanization or

“RHM” project aims to be an alternative to this problem, consequently reducing further

contamination to other people in this work environment. This project is geared towards making a

mechanized hand that will have the full dexterity of a normal hand and be remotely controlled,

giving it the opportunity to enter hazardous conditions and carry out various and endangering

human duties.

The robotic hand can also theoretically help weaker individuals grab and operate objects

with more precision that would be either too dangerous of a situation for an individual or, with

further improvements, too heavy. With advances in technology, robotics have begun to become

more capable and are able to go where humans can not or should not go. The concept of the

finished project has many uses and would be a great way to demonstrate the knowledge of

Engineering Technology.

Examples of robotic application:

Unmanned submersibles EOD robots (Explosive Ordnance Disposal) Robotic Surgical Systems Chemical Testing Robots UAVs (Unmanned Aerial Vehicle)

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DESIGN

The previous design was a good step forward towards copying the motion of a real

human hand, and the improvements that we’ve added to their design will bring it even closer to

our goal. One of the more crucial components that has been changed is the rotating screw that

controls the opening and closing of the fingers. This has been modified to have the capability of

completing this motion much quicker in a more compact form. The bracket for the rotating screw

and sheath were separated for more flexibility. Holes were added to the bottom digit of the

fingers to allow a servo motor to control an extra degree of freedom, circular motion of the

fingers. The palm should be a more accurate representation of a realistic human hand by adding

more freedom to the thumb and possibly some further improvements.

PROPOSED TIMELINE & DELIVERABLES’ CURRENT STATUSDeliverables :

1. Finish a redesign of the handa. Design new parts - on goingb. Assemble SolidWorks parts - on goingc. Assemble wiring throughout hand

2. Programing finger movementa. Redesign the DC motor screw - on goingb. Controls for wires(3) for a fingers(4) - finishedc. Controls for wires(3) for thumb - on going

3. Control glovea. Design new glove - on goingb. Assemble glovec. Program glove readingsd. Connection to fingers

Timeline:Oct 5th - 19th:

Research and design the fingers for more articulate method-finished Design fingers in SolidWorks-finished Assemble fingers/wiring- on going activity Research new glove sensors/communication-finished Research replacement for DC screws for fingers-finished

Oct 20th - Nov 4th:

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Assemble glove sensors Start coding glove sensors-on going activity Implement/test improved microcontroller for the hand -on going activity Assemble replacement for DC screws for fingers-finished

Nov 5th - Nov 19th: Connect finger wires to DC replacement - N/A since we decided to use the same

DC motor Program all finger movement functions- on going activity Create working glove-on going activity

Nov 20th - Dec 2nd: Connect fingers to glove Finalize the code the glove sensors to fingers Prepare/critique end of semester final presentation

REVISED TIMELINE:We started to deviate from our initial timeline. We ran into some roadblocks that took

more time than expected. We also formatted our initial timeline to yield a completed project at the end of the first semester. Our revised time line is:

1st Semester: Research and design the fingers for more articulate method-finished Design fingers in SolidWorks Assemble fingers/wiring Research new glove sensors/communication Research replacement for DC screws for fingers First Final Presentation

2nd Semester Start coding glove sensors/ create program for the Leap Continue and Refine the 3D printed hand Design Implement/test improved microcontroller for the hand Assemble replacement for DC screws for fingers Connect finger wires to DC replacement Program all finger movement functions Create working glove Establish connection to all fingers to glove Finalize the code the glove sensors to fingers Prepare/critique end of semester final presentation

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ISSUES & PROGRESS

Instead of using two Raspberry Pi's, we have decided to use just one Raspberry Pi 3 as a

central hub, or the master, to control 2 Arduino, or the slaves. Originally, we decided to do 2

raspberry pis and one arduino for the glove, but we hit a roadblock when trying to communicate

between the 3 also the raspberry pi doesn’t have enough pin out this would cost complication

when we program the hand. We decided this is not the way to go and we decided to use a

arduino mega instead. This will give us more option in circuit design plus since we don’t need

the microcontroller that drive the motors to do that much calculation, the mega is a good fit for

this purpose. This process is achieved by assigning the 2 Arduino to a specific channel created

by the Wireless transceiver, NRF24L01 will be assigned as slaves and 1 more of the transceiver

will be the master, this will be the one connect to the Raspberry Pi. The decision of using the Pi

for the hub came because we know how difficult it is for Arduino to fail. So it’s best just to let

Arduino send out and receive simple signal rather than do some complicated calculation. We

have successfully control a servo motor with a flex sensor locally. For the articulation sensing

process, right now we are deciding to use an EMG sensor. It’s a muscle sensor that send a signal

to a microcontroller when a muscle is moved. We are also looking for alternative solution despite

choosing the EMG sensor. So far, we are considering ways to track the movement of the finger

rather than trying to find the position of it. After resizing the actuator and consult with our

advisor, we decide to find a better solution for our actuator. Some of the issues that we ran into

while trying to design the fingers and the actuator. The learning curve that we have to

compensate was more than we thought. Our experiences with SolidWorks are limited and that’s

also one of the reason why our timeline is being delay. We spent more time than expected

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researching components to fix some of the issues experienced by the previous group and also to

adapt to our control methods. This made us fall behind on our initial timeline.

PERSONAL PROGRESS

JACE BABIN- At the start of the semester, we went over this project with the students that

previously worked on it and talked with them about what they did and how they went about it.

From there we talked about the issues they were having and what they were trying to do. We

have talked with our advisor Cris Koutsougeras about what he thought about the project and how

it can be improved. After talking with Bach on what we should do, we decided that we want to

do wireless communication with the glove and the 3d printed hand.

So, I have been working on was to establish the wireless communication. At first, I tried

considering ways of having two Raspberry Pi 3s but as I did research and considered was to

accomplish this type of communication. There weren’t any practical ways of connecting two

Raspberry Pi's wirelessly. It just became too difficult and impractical to go about the

communication this way.

I spent a couple of days of researching ways to do some wireless communication with

microcontrollers and found a few ways to communicate with each other. The first way involves

using a NRF24L01 transceiver module, one would be setup as a transmitter and the other would

be a receiver. The second way to communicate would be with a HC-05 or HC-06 Bluetooth

module and pair the two microcontrollers another option to the module would be a Bluetooth

shield. The third way that I consider was to use a ESP8266 module which is like the NRF24L01

module but has a longer initializing phase before it starts transmitting and receiving.

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The NRF24L01 module are good for sending data but the problem with them is that they

can be hard to work with. They have power issues that can cause the signal to be distorted

because of inconsistent power draw. The HC-05 or HC-06 Bluetooth module would be a good

option if we go the route of using the LEAP motion because currently the Raspberry Pi does not

support the LEAP motion. In that we could use the LEAP and have a python script running that

would collect the information about the hands and finger positions and send it via Bluetooth to

an Arduino with a motor shield. The ESP8266 module is another consideration that could work

in a similar manor as the NRF24L01 but they also have unreliable power needs and would

require additional circuitry to get the required amount of power for the module to work properly.

After talking with Bach on which wireless module to use. We decided to give the NRF24L01 a

try and see if it could accomplish what we want to do.

I spend a few days with the NRF24L01 transceivers to try and get them working with

each other. Most of my concern with the module is that it has been unreliable. What I thought to

be communicating with each other was just interference that the receiving transceiver was

picking up. I have been going through some guides online where people have used the

transceivers to transmit data, and they have been using 0.1uf to 10uf to solve the problem. So far

this has not solved the issues that I am having with the transceivers. I have tried multiple

transceivers thinking that one of the ones I was using was a broken but I was getting the same

results even after switching out multiple modules. I was trying to send data from one Arduino to

another using the following code.

Sending code:

#include <SPI.h>#include <RF24.h>

RF24 radio(7,8);byte addresses[][6] = {"0"};

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struct package { int id = 1; float pos = 10.0; char text[100] = "Text to be transmitted";};

typedef struct package Package;Package data;

void setup()  { Serial.begin(115200); delay(1000); radio.begin(); radio.setChannel(115); radio.setPALevel(RF24_PA_MAX); radio.setDataRate(RF24_250KBPS); radio.openWritingPipe(addresses[0]); delay(1000);}

void loop() { Serial.print("\nPackage: "); Serial.print(data.id); Serial.print("\n"); Serial.println(data.temperature); Serial.println(data.text); data.id = data.id + 1; data.pos = data.pos + 0.1; delay(1000);}

Receiving Code:

#include <SPI.h>#include <RF24.h>

RF24 radio (7,8);byte addresses[][6] = {"0"};

struct package { int id = 0; float pos = 0.0; char text[100] = "empty";};

typedef struct package Package;Package data;

void setup()  { Serial.begin(115200); delay(1000); radio.begin(); radio.setChannel(115);

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 radio.setPALevel(RF24_PA_MAX); radio.setDataRate(RF24_250KBPS); radio.openWritingPipe(addresses[0]); radio.startListening();}

void loop() { if(radio.available()) {   while(radio.available()) {     radio.read(&data, sizeof(data));   }    Serial.print("\nPackage: ");   Serial.print(data.id);   Serial.print("\n");   Serial.println(data.pos);   Serial.println(data.text); }}

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ANDREW BROUILLETTE

This semester I have started taking the old hand apart and playing with the screws to see

if there are any design ideas we can add to improve the design. Bach and I consulted Alex and

Bryce that some design improvements would be to make the DC motor shaft fit into the screw

rather than having a screw drilled in on the top of the screw to hold the shaft in place, and by

adding two extruding pieces at the end of each screw to prevent the screw from being pushed out

of the holder when the DC motor pushes or pulls. These designs have been implemented in our

most recent design. I have tested different types of tubing to protect the wire. I am finding that

the tubing makes it very difficult for the hand to fully close. I am looking for ways to prevent the

tubing from getting in the way of the hand opening and closing. I have considered using linear

actuators instead of the DC motor rotating the designed screws, but all of them are far too slow

for our purposes. I have been working on Arduino motor control. I have started to program the

Arduino to read a flex resistor and activate a DC motor. I can get the flex resistor to control a DC

motor. Now, I am attaching the resistor to glove and begin to test and see if the resistor will

perform as expected. The biggest issue will be if the flex resistor will unfold completely back to

the upright position or if it will stay slightly bent. The flex resistor will need to be fastened down

securely to prevent any play of the resistor so it will not be giving off false readings. The EMG

muscle sensor has come in, but I have not had a chance to get my hands on it yet. I will start

testing it as soon as possible. This sensor will be placed inside the glove to read the potential

difference of the muscle when it is activated or not.  If this sensor fails, I have researched a few

other options. I have considered using an accelerometer however this sensor has lead me to a

dead end because the position would just be an estimate and would have inaccurate results. The

accuracy will be very poor. After this dead end, I started to look at position tracking rather than

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finding the position from a sensor. This would require the use of IR tracking. This will allow us

to find the position of the finger in real time. This method is starting to run into a dead end as the

LEAP motion capture will be a more streamlined approach. We are currently considering both

ideas. We are still planning to use the micro servo to control the articulation of the fingers.

BACH NGUYEN- For this semester, my focus as group leader is to get everyone on board,

focusing on attempt to get some better designs for the hand and screws; in addition, I have been

working on getting the glove to work with the hand with Andrew Brouillette, research ways to

capture the most of the motion of the finger and the hand, and Jace on communication between

the devices. I also consulted Bryce and Alex with the current design of the hand.  I'm also in

charge of the designing the glove, researching components and the parts we needed for the

project.

After researching and comparing to other alternative, angle sensors like the TLE5009

E1000 needs a magnet as a reference point. From there it use this relative position to calculate its

cosine and sine in which can be translate to an angle.

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If we want to use this sensor we would have to have one for every joint. In addition, we would

need a separate sensor. We were suggested to consider encoders to control the articulation but

with the current encoder technology encoder they are still too big to use to measure angle and

such. Not to mention it would cost a fortune to purchase the Ultra-small encoder which is 1.0 cm

in diameter.

The device above is made by the Microtech Laboratory Lab. It’s the most precise rotary encoder

to be used to measure the rotation of electronics. For this device to be able to measure the human

finger movement it would have been half the size and would have to be an implant. I found out

there are 2 reliable option for the motion sensing. The first is to try to use the EMG sensor which

is a muscle sensor. It works by sending a signal after a muscle movement. The weakness of using

the EMG sensor is that there is not really a way to tell that if it’s moving a finger or the whole

hand because the sensor itself is quite big. But it can still be use for the forearm movement

sensing if we ever got that far.

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The second option is LEAP motion capture.

The picture above is the barebone visualizer for the Leap Motion Controller.

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The Leap consist of 2 cameras and 3 multi-sensors. The Leap Motion Visualizer only made to

detect hands and fingers. It can also track the wrist movement. The rest of the motion for the

hand it uses a complicated algorithm to calculate the best position of the hand and project it on a

computer screen. The limitation for this device is that it’s bound to a computer as of right now

because of the large load of computing that it needed to guess the position of the hands and the

fingers. We won’t be able to use a raspberry pi for this device. Because the SDK for it is so

versatile with a wide range of languages, we are planning to use this and python to control the

arduino via bluetooth. During the next month, I would like to have a better design for the screw

and the way it works. Also, I’ll be continuing to assist Jace with his connection problems or find

a new way to connect the hand to a control device.  

BRYCE SCHELL- Essentially, there’s always improvements to be made. The main goal of this

semester is to work on improving the 3d robotic hand that was previously shown as a proof of

concept by editing the last group’s work. I created a few holes in the bottom digit of the finger

which will be used to increase the articulation of the fingers via an added servo motor. In the

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previous design, the rotating screw scraped up against metal screws that were holding the dc

motor to the bracket. I’ve accommodated for this by making indentations for the metal screw

heads to sit into to as well as shrink the rotating screw. The rotating screw and coupled sheath

were resized and modified in order to make a more capable and quicker movement via reducing

the number of turns that it had to complete. The inside of the ball socket was rounded off, for

easier movement. After printing these parts out, it was decided that the screw needs further

modification. It should be more compact and strengthened with a double helical spiral. I’d also

like to implement a way to stop the screws from popping out of the sheath, as suggested by

Andrew and Bach. We discovered that the ball socket was too brittle to force the ball joint into. I

split it into two halves, which will be fitted around the ball joint and then we’ll glue the two

halves together. More work will need to be done over the winter break and in the next semester

to finish these designs and implement them into a working robotic hand.

ALEX STEIN- The beginning of the semester, my focus was to remodel the previous

SolidWorks parts. After obtaining the old SolidWorks files from the old model, I formatted them

to the current SolidWorks 2016 and fixed the main files being worked on that were having issues

being suppressed or files that were unable to be located. When the parts were ready to be worked

on, we researched how to modify/create the parts needed to make a more advanced robotic arm.

Next, all the parts had to be resized to a smaller and more proportionate and realistic hand size,

while keeping some of the main features like screw holes the same size to be able to use.

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The DC motor bracket along with the screw linear actuator bracket was completely

remodeled which would increase the speed while decreasing the size and material used. The

linear actuator has went through many different designs leading up to a double helix look alike

model that our advisor wanted it to be.

After deciding to stick with the gear motors used by the last group, I went and got the

GM25-370CA gear motor dimensions online and remade the DC motors on SolidWorks to make

sure that there would be no problem with anything not fitting correctly and to accurately have a

perfect bracket and Linear Actuators that could accommodate the gear motors.

The brackets for the DC motors have been completely redesigned to be one bracket

instead of five. Before the five DC motors had too much width that could not fit into an robotic

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arm, but having the bracket stacking the DC motors on top of each other will make the setup fit

into the robotic arm. Also, with the rework of the bracket, better support of the DC motors have

been added at the back of the bracket to prevent wear and tear on the bracket.

Along with working on SolidWorks parts for the project, I have been meeting with the

whole group have been meeting up in the lab discussing as a team about the project and helping

each other if needed.

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As for coding, earlier this semester I have made a code in Python 3 using inverse

kinematics that could move two segments of different lengths to get to a targeted point on a two

dimensional surface.  I then used the formulas I learned for the Python code to control a four

degrees of freedom robotic arm in a real world environment that I made this semester using an

Arduino. The following code is part of my arduino code that uses inverse kinematics that

controls two segments to go as close to the targeted position given by an input of an x and y

value as possible to drop off whatever the hand was holding.

void Dropoff(double xe, double ye){double y = ye - 4.5;        // base is raised 4.5double x = xe - 2;          //first segment is shifted to the left approx 2cmdouble b = 19.5;    //first segmentdouble a = 13;      //second segmentdouble D = atan2(y,x)*180/pi;  //degree of Ddouble c = sqrt((x*x)+(y*y));  //lenght of c//if it is out of distance if (c > a + b){   double  x = x * .999;   double  y = y * .999;   double c = sqrt((x*x)+(y*y)); } double  A2 = acos((-(a*a)+(b*b)+(c*c))/(2*b*c))* 180 / pi; double  A = A2 + D; double  C = acos(((a*a)+(b*b)-(c*c))/(2*a*b))* 180 / pi;  A = abs(A - 180); //convert it to servo  if(A >180){ //servo only goes to 180 degrees     A = 180;  }    C = abs(C - 180); //convert it to servo  if(C >105){ //servo only goes to 105 degrees    C = 105;  } elbow.write(C + EIncrements); delay(1000);  shoulder.write(A * SIncrements); delay(1000); hand.write(180); }

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The code should be able to be used for positioning the arm if we get to that point in the

project, or as of now can be used to help position the fingers of the hand to mimic the glove

sensor readings by calculating all the lengths together that have to change in size and control the

DC motors to increase or decrease the amount of wiring in the fingers that creates the pull to

close the hand into a fist.  

The next steps for the project next semester is to print and add some wiring room to

control the movement for the redesigned hand. The old palm still needs more work for next

semester to have the wiring coming from the linear actuators fit into the palm correctly. The

fingers could be redesigned and arm could be designed along with any other programming that

will need to be done like accommodating some of my inverse kinematics once the sensor

readings from the glove work. After the parts have been completed, I will help continue to help

the team’s progress towards the project’s completion.

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CONCLUSION

This was a very exciting and a different semester for the group. Not fully knowing what

to expect coming into senior design, I think everyone in our group working on the ‘3D Robotic

Hand Continuation’ project had put in a lot of work into this course. All of us had a part to do

and each of us put countless hours into researching, for each task and dilemma that was ahead of

us, meeting up together all over campus, especially in McGehee Hall, to talk about the project

with each other and understand exactly what must happen this semester for the course, and trying

to finish our own assigned tasks to make sure that the group stays productive and finishes on top.

For Spring, we are determined to finish what we have started. All of us have learned from

this semester how to handle senior design and know what should be done for next Spring. The

difference in the amount of time we will have for senior design II will be vast compared to the

late start we had this Fall. Also, knowing exactly what to do on the first day will be a big factor.

This project has certainly helped us realize what it takes to be an engineer, requiring problem

solving skills and teamwork. This insight will give us more determination towards completing

this project in the future semester.

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References

Ackerman, E. (2016). This Is the Most Amazing Biomimetic Anthropomorphic Robot HandWe've Ever Seen. Retrieved October 06, 2016, fromhttp://spectrum.ieee.org/automaton/robotics/medical-robots/biomimetic-anthropomorphic-robot-hand

Dexterous Hand. (n.d.). Retrieved October 06, 2016, from https://www.shadowrobot.com/products/dexterous-hand/

Guizzo, E. (2011). Building a Super Robust Robot Hand. Retrieved October 06, 2016, from http://spectrum.ieee.org/automaton/robotics/humanoids/dlr-super-robust-robot-hand

GM, NASA Jointly Developing Robotic Gloves for Human Use. (n.d.). Retrieved October 06,2016, fromhttp://media.gm.com/media/us/en/gm/news.detail.html/content/Pages/news/us/en/2012/Mar/0313_roboglove.html