Archive for October 2012

Fourth Meeting

Dr. L#### suggested to use DC motors because of their low cost and it may required at easier circuit and manipulation from the pic18f26j11. The reality after researching in this matter seems to be that we will reduce accuracy to gain in price and time.

In the link below you can find a definition in the types the motors you can use and their characteristics. Until now I still think the steeper motors are the most accurate.

All On Robots Website

After researching prices for motors  and baring in mind that micro-motors will be better for the project since we thinking to go for the smaller and more precise adding a gearbox to the motor but their cost is too high for our project.

In his book Robot Builder’s Bonanza, Gordon McComb mentioned how you can create robot from recycling parts, what he calls “Building Bots from found parts”. There are lots of other people which recycle material from people waist, normally hobbies. The decision was to trying to minimize the cost of the motors and get the more efficient, in this case talking about accuracy. This could be archived by using unwanted printer motors. We have dismantle and old Epson printer and taking the two motors. Printers are really accurate and for this prototype will be perfect to use them.

Printer motors are accurate the only negative site is difficult to find the specifications of the motors since there is not model number the only description found is; EM462 for one of the stepper motors and EM463 for the other stepper motors.

(There will be required some testing to get the values of the motors.)

Solidworks first design.

This is the first finished design created in Solidworks, which is a cad software provided by university.

robot1

First Robot Design using Solidworks

 

I decided to use the Planetary Gearbox Stepper: 42BYGH40(M)-160-4A NEMA 17 Bipolar 99.55:1. After looking in libraries for a design of those for cad software solidworks and since I am still developing my skills in Solidworks  the decision was created my own, it will be required a cad software to view or manipulate this file (Solidworks eDrawings free for viewing this file).

The dimensions of the motors were taken from the mechanical drawing from Active robots websiteThe motor was intended for demonstration purposes, after realizing their price with our budget been £50; it was required to find another solution.

Third meeting

Group meeting where Dr. L#### told us a general approach of the projects and he also mention that we all have similar parts in our projects. We all using same microprocessor the pic18f26j11.

He mention that some people will be using wireless communication RF650 (433Mhz)  , other will use an ADXL325 accelerometer with 3 axes, the rs232 will be use for serial communication for those that we don’t have to use necessarily wireless communication

I will be testing a ADXL325 for my project I will need to check the values of X and Y and identify the most accurate value. The ADXL325 will be provided by Dr. ####, I have asked him be he will provided me with a pcb to connect to the pic and read the values that will be send to the computer throughout a usb using rs232.

I need to decided the types of motors I will be using for the project. I think this is essential for my project. The motors could be:

  • DC motors;
  • Stepper motors; unipolar or bipolar
  • Serve motors;

Dr. L#### will help me given a session on Solidworks.

Second meeting

The second meeting was to approach Dr. L#### to discuses about the details of the project and my concerns about the difficulty of it, I am not that comfortable with the electronic side of the project.

Dr. L#### has been really positive about this project and seems that I will not have any problem with it at all. He will send me a brief description for the project to be able to write my project proposal.

During the meeting its been decided that I will have to use the pic18f26j11, this is the one we currently using in class for this term project in Integrated systems design, which I think is in my advantage since we been programming similar functions in the pic for a completely different project.

I been told the interface will be created with vb (visual basic), the design of the robot I been told to use Solidworks even I am comfortable with Autocad seems that solidworks will be much easier and quicker.

The idea is to created a 3d arm robot which will be cut in a laser cutter. Dr. L#### has mention that he can provided the parts if I give him the files in solidworks.

Mark which is a technician from the department has provided me with some good books in Solidworks, he was the one who told me autocad in the first year.

The lab at the moment has not licenses for this software and Mark will add those to a few computers in the library at the same time I have asked Solidwork if they could provided me with a student trial licenses for 60 days.

Working in the lab is not always easy.

From today I will be meeting Panos L#### every Wednesday at 14:00 in the lab.