Robotic Explorer

[jamesker]

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.

[Guest]

Robotic Explorer

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

[jamesker]

Robotic Explorer

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

[woody]

Robotic Explorer

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

[_jl_]

Robotic Explorer

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 $).

[blazerbotics]

Robotic Explorer

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.

[jamesker]

Robotic Explorer

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.

[woody]

Robotic Explorer

How many different operations do you require James?

Perhaps a Futaba FF6 ( 6 channels ).

[jamesker]

Robotic Explorer

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.

[woody]

Robotic Explorer

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

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

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

[jamesker]

Robotic Explorer

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

[blazerbotics]

Robotic Explorer

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

[jamesker]

Robotic Explorer

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.

[Guest]

Robotic Explorer

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

[_jl_]

Robotic Explorer

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).