guidance

[hiyan]

iam a new member .i wantto make a robotic arm which able to write soem words on board.but i dont have exact idea how to start and what to do.
i know that 1st step i need a presure sensors which able to sense teh weight of pen or chalk .but for writing step kindly guide me .how to complet my project

Thanks

 

[bloody-orc]

does it have to be an arm. i assume you have no exp. in robotics so an arm that is able to write is far to difficult for you... at has to have wery good moverability and also it has to be veeeery acurate at all times.

if you want something that can write then i suggest using a plotter that is kinda like an arm. search google for more details.

 

[hiyan]

Thanks for guidance .but i think i woould be possible that Robotic arm take some weight and put down as a mention place .is it?
and i am sure that in future teacher robot will coem in market not batter and acurate as human but still one of a big step .?

taking some weight like egg or packet and sense it's weight will not use presure sensors and 2nd i would like to ask what teh more circuitry require to complet this process?

 

[hiyan]

:?:

 

[bloody-orc]

well... you have to have wery accurate motors as i sed before and have a lot of feedback. then you need to write a software for the motors to ordinate in x,y,z cordinates and also the rotation of the object that you want to pic up etc... as i cant understand very well what your goal is, then it is hard to tell you anything more specific.

the motors i would use would be i think steppers, that have a worm gear attached to it. this makes is wery accurate, slow and strong. if you want a fast thing, you might use DC motors, but you have to have a lot of feedback and the soft will be a bit harder to create.

 

[hiyan]

brother i saw a robotic arm which hold the egg and show the accurancey look like human hand .similarley i also wantto designa robotic arm which i can use in industry for industrial purpose but i wantto make it just closer to human hand .it's my task .


so what u suggest me about this project

 

[bloody-orc]

plz tell us your budget (how much money you are willing to spend), your skill and exp, arm size, the task this thing must compleat. does it have to have fingers or can there just be a tool (like drill, wich makes the construction much easyer). also how much movemant does it have to have like uman arm? 3 links and one rotation?

 

[suicidalmonkey]

A robot, contrary to popular belief, is a device that can read input from various sensors and then act on that information. A robot that takes the form of a human is called a humanoid robot.

A robot arm does not need to take the form of a human arm to be classified as an arm.

There are four main types of robot arm:

• Revolute Coordinate Arm; I assume this is the type of arm you are trying to build and is modeled on the human arm.
  Polar Coordinate Arm; This is a simplified model of the human arm.
  Cylindrical Coordinate Arm; This arm resembles a forlift on a turnstyle.
  Cartesian Coordinate Arm; The work envelope of this arm resembles a box.

More information about all these arm types is available on google.

I think the best arm type (and most simple to construct) to write on a flat board is the Cartesian Coordinate Arm.

 

[hiyan]

Right now i have 20000 is it enough?

 

[bloody-orc]

in dollars, yes
in pounds, yes
in rubls (russian current), not

but i think yes that is enaugh to construct a mighty arm.

what you should start with is in my opinion drawing an arm.
think over how many links you and what tools it will use (how complikated).
also what weight should ei be able to pick up.
What feedback you need from it.
what is the controlling unit (pic, AVR, PC)
wrom what material will it be built.
what motors shall you use (i think you need DC motors with gear down).
how big it should be (how long the arm)
and as sed before, what task (welding car parts/ armwresling/ just fun)
also it would be nice if we know youd experiance (are you a student or is this what you have to do for living)

i think that's it for now...

 

[hiyan]

iam student .that's way i dont have to much knowledge but i try my best to get more and more knowledge .

so suggest me ur best advice.
2nd if i will design arm for welding car parts what kinds of things is necessary?

 

[bloody-orc]

it must be able to weld :wink:
well those arms have a very complex software so i think you are not able to do that. (also it costs a bit more). you could make a electronic components sorter... you pic up a resistor, read the value and put that in the box that has the same resistors. and also answer the othe questions i rized.

 

[hiyan]

very truley in i did not get any Robotic teacher which able to help .and guide 2nd how can i get experiance 3rd after all that thinks all forced me to do in other subjects but i like robotics and i personally effort to get knowledge about this i do and i read . :?:

 

[bloody-orc]

tell us please what have you done before:
*do you know hot to use electronics?
*can you program microcontrollers (with C or assembler) or PC/Läptop(with any language)
*do you have knolage on mechanics (constructing such a thing)
*what tools can you use? only cordless drill and a screwdriver or machanics shop equipment.
*do you have any idea what it should look like?

 

[hiyan]

yes i have use and made many circuits.

yes i know about programming like Dos GWbasic and C and little bit of Assembly and use microcontroller.


and 3rd i wantto make a good robotic arm not to much expansive but not get teh accurate idea.

Thanks brother for repaly

 

[bloody-orc]

ok as you have experiance then you can start thinking about arms moving parts. where to get motors, how much torque must they have, what power consumption, what voltage. Also about the control cirquit. where to get H-bridges to control your motors, how powerful must they be. after you have made block shematic about all what you need, then you can start constructing more acurate shematic.

but before you start making the shematic, you should build that arm. al the mechanical components, motors etc. so you know if you have to add or discard some things, you didn't think before. When you are constructing an industrial arm, i suggest make it from metal (like alluminum).

you can also look other peoples work over the internet. you can find them through google.

 

[hiyan]

Thank u so much


it will really help me to desgin Arm

 

[hjl4]

This is where i would suggest reading up on servo hydraulics.

You can make your own hydraulic cylinders or purchase small ones.

If you are replicating the human arm and fingers, you have your plans already. Make a copy of the "physical size"of your own arm and hand.
Hydraulics are easy to work with and can be very sensitive, and can have feedback potential and be microcontrolled.

This is the only way to go if you want to maintain a powerful package, in relatively small size.

Just a thought.