phoenixgarage.org

 Robotics: A Remote Operated Vehicle (ROV) Project
Posted on 2008-05-29 @ 23:32:04 by r00t

THE CONCEPT:

In the early part of 2005, I began the design and construction of an ROV based on the chassis of a 1/6-scale radio-controlled toy monster truck. Utilizing this and other various items, I managed to implement a working - if not very elegant - ROV system. Though I never obtained any video of it in operation, I did manage to document its construction with a series of photographs.

The ROV started life as a 1/6 scale radio-controlled monster truck manufactured by New Bright. It, and/or similar scale radio-controlled monster truck toys, may still be easily purchased:


New Bright Raminator
Questions or Comments?

Phil's Hobby Shop - New Bright 6684 1/6 Dodge Monster Truck

I purchased the toy from my brother-in-law for a few dollars. Even though it was only two-wheel drive, it seemed like it would make a very sturdy and fairly powerful ROV platform I could experiment with:


Raminator - Before
Questions or Comments?

As you can see, the truck is over 18 inches in length, with the tires around 7 inches in diameter. As mentioned, I didn't take any video of it in operation, but a couple of videos made by others of the same toy show that it seems to be a capable platform for ROV usage:

Raminator Run 2

Phelix The Cat Rides The Raminator

When I originally played with it to determine its effectiveness as an ROV development platform, I had no problem guiding it through dirt, 4-6 inch high grass, or other obstacles. Some larger obstacles couldn't be overcome, mainly due to the lack of four-wheel drive, rather than from any issue of power.

CONSTRUCTION:

Construction of the ROV began with the removal of all the assorted cosmetic parts attached to the chassis. Once removed, I was left with a sturdy plastic tubular frame and drive system. Plenty of mounting points and open spaces for attaching control and other hardware abound:


Raminator - After
Questions or Comments?

Raminator - Leftovers
Questions or Comments?

The majority of the leftover parts were donated for recycling. I did keep the bullbar/skid plate, which I figured may be useful in the future for collision protection and/or for mounting other parts.

I then concentrated on the remote-operation part of my ROV. I decided to utilize a 900-1200 MHz wireless security camera I owned:


JMK Security Camera
Questions or Comments?

The camera has its own built-in low-power transmitter, the signal of which is tuned into and picked up by the silver-cased receiver shown in the picture, which is in turn connected to a TV. This camera, attached to a pan/tilt system, was determined to be the most pratical method for remote usage and control. It would allow for an almost complete 360 degree look-around capability regardless of the orientation of the platform on which it was mounted, which was ideal. Using an old Cox/Sanwa AM radio-control unit and two hobby servos, along with some custom designed aluminium mounting brackets attached to the control horns, I created the pan/tilt unit for the camera:


Pan/Tilt System - Image 1
Questions or Comments?

Pan/Tilt System - Image 2
Questions or Comments?

Pan/Tilt System - Image 3
Questions or Comments?

Pan/Tilt System - Image 4
Questions or Comments?

Pan/Tilt System - Image 5
Questions or Comments?

I stuffed the AM receiver and batteries into a plastic peanut butter jar, mounting the servos to the lid, and the on/off switch to the side. I then attached the security camera to the brackets, and attached the lid:


Pan/Tilt System - Camera Installed
Questions or Comments?

Once the pan/tilt camera was assembled and tested, I turned my attention to the integration of it with the chassis. I decided for ease of assembly to locate the pan/tilt camera unit centrally on the chassis. Double-sided tape was used to secure the bottom of the unit to the chassis and keep it from sliding around:


ROV - Camera Mounted
Questions or Comments?

A piece of thin, 3/16 inch plywood was cut and drilled in such a manner as to provide a secure collar around the lid of the peanut butter jar. The plywood was attached to the chassis using zip ties. The use of double-sided tape and zip ties, while not reccommended for a final implementation, was decided upon in order to effect a temporary yet robust solution, which could be easily removed and/or altered in the future as design needs changed:


Pan/Tilt Collar - Construction
Questions or Comments?

Pan/Tilt Collar - Zip Ties
Questions or Comments?

ROV Version 1 - Complete
Questions or Comments?

TESTING:

This completed the assembly of the initial version of the ROV. By hooking up the camera's receiver to a small television, and using a combination of both radio-control transmitters (one of which controlled the chassis, the other controlled the pan/tilt camera), I managed to navigate the ROV on a circuit around my house. I was quite surprised with how easy it was to control and guide the ROV. I had feared that the limited field-of-view (FOV) of the camera would present an obstacle to control, but this turned out not to be an issue.

THE FUTURE:

When I started the project, I originally had in mind to improve the design of the ROV, with the goal of turning it into something useful for experimentation and learning purposes. Personal issues, however, interferred with those plans during the remainder of 2005, so I was unable to continue with the project. With the recent completion of my web site in 2008, and with no other pressing projects in the queue, I have now decided that it is time to continue with development of the ROV.

My immediate future plans, which I will detail in later articles, include:

These and other planned developments should prove both educational as well as exciting to implement. Stay tuned!

Share This Article

    

Questions or Comments?

If you have any questions or comments about this article, please contact me...

Referencing Articles:
0 comment(s) posted
Post New Thread