During this semester, many advances were made. While shields were ordered for the RaspberryPi, smooth movement algorithms were tested using an Arduino. The algorithm can be found below. In order to achieve a smooth movement, the servo motors have to step one step at a time until it reaches its final position. These steps require a 20 ms delay to make the prosthetic move smoothly. All of the servos can move individually and make basic gestures. Issues arose when three servo motors were driven to make more complex gestures. The two wrist servos (HITEC HS-422) can be powered together to have an output of a waving motion (a video is attached below along with the program). Issues arose when a third servo was introduced to raise the elbow. The servo in the elbow is an Alturn ABDS-996HTG+HV. The Arduino powered these servos with different duty cycles, which leads me to believe that this causes the issue. The elbow motion video below is supposed to incorporate the waving motion as the elbow bends like a humanlike wave. Along with these achievements, the RaspberryPi was received with all of the required shields for this project. The Pi’s Linux operating system was installed and is now up and running.

The next steps for over break are to transfer the servo movement from the Arduino to the Pi along with correcting the duty cycle error so different servos can be driven at once. Then, EEG/EMG signals will be analyzed and mapped for certain movement patterns using PowerLab 8/35. Lastly, if the shoulder servo is received it will be installed on the prosthetic. 

To begin next semester, the Pi’s A/D converter shield will be experimented with. Once the hardware is understood, databases will be created for the EEG/EMG signals. This will set everything up for creating the full algorithm for the prosthetic.

Videos:

Waving Motion

Elbow Motion

Program:

SmoothServoProgram

Servo:

BephaMart High Voltage High Torque Servo

This is the last week of the semester. The servo motors on the arm had to be readjusted so the arm is actually a right arm and can move like one. Tests were done to check the proper angles of each servo to make the movements lifelike. These notes can be found below in the scanned notebook. Also during this week, basic smooth gestures using the arm were made (allowing the wrist and hand to wave). When applying more complex gestures issues arose. The two wrist servos and the one elbow servo wouldn’t run together. Therefore, the arm couldn’t lift at the elbow and wave. I believe it is due to the different duty cycles being received by the servos. Tests can be found in the notebook. Lastly, data was given to Karissa and I based on the brain signals. The results can be found in the scanned notebook below. It shows that the electrode placements on channels 3 and 5 produce the same signal. One final update will be made for the progress at the end of the semester and the next steps.

Scanned Notebook: Week-15

Project Proposal

Week 14 was limited to one class. During this period, a draft of the project proposal was written up and can be seen in the scanned notebook below. This includes the project deliverables, milestones, and WBS.

Scanned Notebook: Week-14

Week 13 consisted of project management information. Information was given to the students about the project proposal and what should be included when the document is written up. Additionally, DC motors will not be used to drive the shoulder. This is due to limitations in the movement. Instead higher torque servo motors that can rotate 180 degrees will be ordered. As of now it is the HITEC HS-805MG. 

Scanned Notebook: Week-13

This week was designated to achieve a smooth movement of the hand and arm. We found that it is best to use a 20 ms delay between steps of the servos to make the movement look more smooth. We found that the shoulder servos will not support the desired movement. It doesn’t have enough torque to support the weight of the arm and also doesn’t rotate a full 180 degrees. This limits the use of the prosthetic arm and doesn’t fully mimic a human arm. Therefore, we decided to replace the shoulder servos with DC motors. Research was done this week too to find what servos are attached to the arm and the voltage range they are allowed. The last page in the scanned notebook found below is the week update presented to the class and instructor. 

Scanned Notebook: Week-12

This week was used to research frequencies related to EMG/EEG signals. We found from the brain stem study results that the signals send at 1 kHz and the values range from +- 1.3 mV. Also, we found that we need an analog to digital converter and the Raspberry Pi does not have one so a shield that offered this function was ordered. 

Scanned Notebook: Week-11

This week began by discussing every project as a class to get insight. This day, the beginning process for starting the arm and hand project has been outlined. This can be found in the scanned notebook found below. The second class of the week was designated to thinking about what type of hardware would be best to use such as processor and sensors. Along with this I learned how beneficial it is to record all documentation to return back to in the future if needed.

Scanned Notebook: Week-10

Weeks 8 and 9 were designated to determining what my next project for the rest of ECE 454 will be. Ideas presented to the students can be found in the attached notebook. I soon chose to work on the prosthetic arm and hand. Some notes regarding the assisting hardware and software for recording EEG/EMG signals were taken in the notebook. Lastly, the template for the project questionnaire can be found in the notebook. This questionnaire was started in the notes for the prosthetic arm and hand. The final copy of the questionnaire is attached below. 

Scanned Notebook: Weeks-8-9

Project Questionnaire: Arm&Hand-Questionnaire

Week 7 was reserved for project closeout. This included a final project update(post) to inform the next user where he/she can pick up from. The next steps will be to write the Final Project Report and post it for the sumo bot. The scanned notebook found below has information regarding the final report and what should be included in it. The second log in the notebook for the week was for the upcoming project and what needs to be incorporated. The next steps are to come up with a project idea for the rest of the semester and next semester. 

Scanned Notebook: Week-7