Robotic Explorer

Hi, Im currently desining a robot for a school project which would have a robotic arm on the top of a 4 wheel drive chassis. The chassis size is still to be decided but im estimating it to be about 100cm byt 75cm. The chassis would be made up of 1 inch box steel welded together. I am curerently finding it very difficult to obtain any infomation on robotic arms particulary controling and powering it. The whole point of the robot is to be a replacement for a journalist to veiw images in dangerous zones. It will run on 2 bosch 750 watt motors turning 4 rear go kart wheels via sprockets. The end effector of the arm would contain the video camera which would send the video via a modem or wirelessly. Please could someone advise me on how to power the arm and how to control it also where to buy the components from ? It will have a some weight on the end of the arm so I am unsure weather I should use low pressure pneumatics or stepper motors. The biggest problem is acheiving the arm action to be as smooth as possible without any sudden movement. Thnak you for taking your time in reading this message and I would appreciate any feedback regarding this. Thanks alot.

You have the choice between linear actuators, pneumatics and hydraulics. Linear actuators will probably be your best bet.

HI, thanks for the reply, are the linear actuators expensive and do you know where they are sold ? Thanks.

http://www.robotstuff.freehomepage.com/http://www.robotstuff.freehomepage.com/

I guess buying an industrial robotic arm is too expensive, so I agree on linear actuators (unless you could find a used industrial arm).

And for the rotational movement (of the camera) you want a slow motor/gearbox set (for steady motion).

Stepper motors work fine, with proper control...but how do you get proper control without lots of £ (or possibly $).

try http://www.milinst.com/robotics/robotics.htm#tecarmhttp://www.milinst.com/robotics/robotics.htm#tecarm dunno if its big enough for what you want.

I have to completely make the project and so I cannot buy just buy the arm. It would make it alot easier if that was the case though. Is the only way to control the arm by radio control and if so which remote has that many channels which can be used to control the tank track steering and the movement of the arm ? Thanks again.

How many different operations do you require James?

Perhaps a Futaba FF6 ( 6 channels ).

That might be an option. I need all 6 channels though and some of the channels on the FF6 are not controlled by the joystick. They are just switchs any ideas ? Thanks.

James ....Please could you specify your requirements.

2 Channels for drive ( one joystick )....

Then what ? ...Pan & Tilt of arm ? ... etc

Hi, the robot arm will have 4 degrees of movement for the waist, shoulder, elbow and end effector.

why do you need so many controls over the camera, surely just pan and tilt is all you need? channels could be with a 6 channel system;

Fwd/Bck
Lft/Right
Tilt (up and down)
Pan (scan left and right)
Video power control
and one spare

I really dont want to do that because the robot is suppose to simulate a real journalist using all the degrees of movement that a camera man would use. thanks.

Then use two radios? One person would drive, while the other operates the camera.

You propably want some form of customized joystick, you can get joysticks with 4 axis per stick, then you can control the entire camera with your right hand and then drive with your left.

Two radios is an option (if you want 2 peole to drive it), but in that case I thint it would be cheaper to extend some of the channels with a cable to the second person. That is, if you are satisfied with 7 channels (max if you do not look at extreme things).

Hi, does anyone know where I can get customised joysticks with the 4 axis per stick? thanks.

Oh...I did not mean customised as custom built, I ment using a joystick not intended for radio transmitters. Like a PC joystick (which is propably an expensive option, you cant use the electronics anyway).

Have you got a laptop? If so, you could use Bluetooth to control the robot. It would be possible to use a PC joystick for control, and view the image from the camera on the laptops screen. You would need a Bluetooth transmiiter card plugged into the laptop, and a reciever in the robot. However, you would have to write your own software to control everything. Ive got no idea how much it would all cost, though.

Thanks for all the ideas but I think that writing my own software will be much to hard for me. I think I will have to use 2 radio controls. If anyone has any ideas please can you post it as I need as much feedback as possible to make my project possible. Does anyone know which radio is best and as this is a school project would it mater if i use 35mhz or will I have to use 40mhz ? Thanks again.

Would you think i would be able to adapt these linear actuators to control all of the degrees of movement? If so it would work out to be alot cheaper than I expected also does anyone else know of any places which sell used/referbished stepper motors suitable for this project reasonbally priced? Thanks. http://www.robotstuff.freehomepage.com/catalog.htmlhttp://www.robotstuff.freehomepage.com/catalog.html

35mhz is for aircraft only, use 40Mhz.

http://www.bullnet.co.uk/shops/test/http://www.bullnet.co.uk/shops/test/ all sorts of stuff.

Can you buy 8 channel 40mhz radios if not whixh is the best 6 channel one? Thanks again.

I have Multiplex 7 channel Cockpit and a Multiplex 9 channel Commander, just because I like multiplex.Not that I need the channels.

Can you buy the Multiplex in the UK. Thanks

I dont know, as I live in belgium.

yes you can i got one in sheffield

Lee, how much did you pay for it and is it 40mhz. Thanks.

http://www.ss16.dial.pipex.com/Multiplex/Radio%20Equipment/Transmitters/Royalevo.htmhttp://www.ss16.dial.pipex.com/Multi...tters/Royalevo .htm


Ideal for what you propose....

it was 2 yrs ago and i think it was around £140 yes it is 40 meg

yer that looks ideal nice looking set too

there website is down at the mo but this is there no 0114 2511761 it is called model shack

Price for this level of technology is however off putting ...
ROYAL evo9 Vario-Set with HFM-4 40/41MHz, £421.70

ROYAL evo12 Int.-Set with HFM-S 40/41MHz m.Scanner,£924.38

With various configurations and prices in between.

the one i have is just the basic model 4 chnl it as the chnl mix and the normal bits simple to use come to think of it it as to be for me to use it :)

That evo 9 looks ideal but it comes at a price. What could I do on that which I couldnt do on a 6 Channel Fieldforce since I really only need 6 channel but i would want the channels as joystick movement not as switches. I might just have to resource to using 2 controls. Thanks for all this advice.

In the worst case you can buy 2 Graupner X412 RX TX sets; ‚140 each, so about £220. 2 6 proportinal channels and 2 on/of channels at your service then.

Does anyone have any second hand radio controls which they would be willing to sell? Thanks.

Im very nasty, but the Multiplex Cockpit 7 channel can be obtained. But not cheapely, P&P is a real killer.

How do you mean? thanks.

look on ebay there is normaly some on there

Hi, if i was to use tank sterring is it possible to use pistol grip radio controls? thanks.