Rov Reboot (3D Printed Rov)
Re: Rov Reboot (3d Printed)
Even though this was just going to be a small observation Rov I still kind of planned on adding a small manipulator to it anyway. The only problem is I will only be able to control either the manipulator or the tilt for the camera at one time. I'm going to try and make the manipulator easily removable and with modular grippers. This is a 50% version of the 3D Printed Manipulator I designed before... ... and this version will be a 3D printed design based off the gripper I made out of a Radio Shack Armatron that I used on my Seafox because I really like the parallel gripper design better I think. The gripper design uses a worm gear setup just like the original Armatron. I added some hooks to the grippers tips to add some versatility so you could close them stick them in a hole and open the gripper to grab the item with the hooks. The main arm and housing will be made from PVC Pipe and Fittings and use a shaft seal much like my Seafox manipulator. (The shaft is not shown in these diagrams.) There are quite a bit of bits and pieces to this design because I am incorporating a clutch into the motor. The Original Armatron Gripper had springs on the fingers that wouldn't let you stall the motor when it was closed all the way, my clutch design will accomplish the same idea. This may limit the gripping force but being as this is such a small Rov I won't be lifting much anyway. The clutch is basically just a slip clutch, the triangle surface on the green part mates with a corresponding cut out on the orange part and when the force is to much the entire motor pushes back against the spring and the mate is broken. This is another view showing the mating surface of the orange part. The modular part will use easily changeable gripper heads. This one being a golf ball grabber. This design could be used as a soil or water sampler. These are easy to print so the possibilities are endless.
Next it's on to the actual construction part.
Re: Rov Reboot (3d Printed)
I always get emails on how I went about making the manipulator for the Seafox so I'll try to give a break down of how this one is made as I go. It does require machining some of the parts so a small lathe is required.
For this one I started by squaring up the ends of a piece of 3/4" PVC Pipe.
Next I trim off a small section of a 1/2" PVC Coupler. (This will be the front section of the main arm housing.)
Then I turn the coupler around in the chuck and chamfer an angle on the front edge. (This is purely for aesthetics.)
Next its on to the seal seat piece. I start by trimming off the flange of a 1/2" PVC Plug.
I then drill and bore out an area to create the seat for the actual seal.
Turning that part around in the chuck I have to turn it down just a bit so it fits inside the 3/4" pipe.
These are the machined parts so far.
The seal is pressed into the seat at this point. I'm using a 3/16" shaft so this is a 5mm Yamaha motorcycle oil seal. (I'll have to find the part number and update this later.)
Using a PVC primer and glue the seat piece gets glued into the pipe (seal facing out) and then the front section gets glued onto the seat piece. (I couldn't take pictures while assembling it because I need to stick the pieces together while the glue is fresh.)
This is how the seal should look.
After that the assembled piece goes back in the lathe just to clean them up.
The main housing all cleaned up and I'm ready to work on the internals.Re: Rov Reboot (3d Printed)
Colored parts explanation from left to right.
- Purple/Grey part is the seal/seal seat part that was glued into the main arm housing.
Yellow is a bushing to hold the shaft centered (I didn't feel a bearing was needed on this one.)
Orange is the shaft side of the slip coupler.
Green is the motor side of the coupler.
Grey is the 10 RPM gear head motor.
Red is the spring cap (this holds the spring centered and away from the motor terminals.
Next is the spring.
Light blue is the internal motor housing.
Re: Rov Reboot (3D Printed Rov)
Well back to the drawing board.....
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- Joined: Jan 3rd, 2014, 10:04 pm
- Location: Vancouver B.C. Canada
Re: Rov Reboot (3D Printed Rov)
That's a great design. I'm looking forward to seeing it in action.
Re: Rov Reboot (3D Printed Rov)
The Saga continues....
Re: Rov Reboot (3D Printed Rov)
Here is the other printed gripper. Everything was printed in PLA with the exception of the pads on the fingers. I printed these out of a flexible rubber material so they would have better grip. It uses some 4-40 and 2-56 screws for assembly and a 1/8" stainless steel rod for the gripper shaft.
The gripper shaft has a flat spot ground in it for the 4-40 set screw on the worm gear.
This smaller shaft of the gripper will mount to the motor shaft though a coupler. This will allow the grippers to be easily changed out when needed.
I next cut a 6" long piece of 1/2" PVC pipe to use as the arm of the manipulator. Using the gripper assembly I mark the location of the mounting holes for the gripper. The first mark is for the mounting screw and the second mark will be the access hole for the coupler set screw.
After drilling several holes through the arm on both the top and bottom the arm is glued to the motor housing portion of the manipulator. (some of the holes are for drainage because the arm portion of the manipulator is not water tight.)
A quick test fit of the gripper is next to make sure the set screw access hole is in the correct position.
I am using a piece of 3/16" stainless steel rod for the motor shaft. Again a flat section is ground into the shaft for the shaft slip clutch coupler set screw.
Next the bushing is placed on the shaft and the shaft is inserted into the housing and through the seal.
I then mark the center location of the set screw in relation to the motor shaft.
I made a coupler out of aluminum to join the smaller gripper shaft to the larger motor shaft. I then mark the location where the motor shaft needs to be cut as well as how far in inserts into the coupler.
After cutting the shaft to size and grinding another flat on that end (not shown) the shaft is reinserted into the motor housing. I temporarily attach the coupler to a scrap piece of the gripper rod so I can insert it into the arm and affix it to the motor shaft.
I secure the set screw in the coupler to the motor shaft through one of the holes in the bottom of the arm.
With the motor shaft and coupler in place I can go back and trim down the gripper shaft to length and grind the set screw flat on the end. (this is done with the shaft removed from the gripper)
Then is just a matter of sliding the gripper in place, securing it with a 4-40 flat head screw, and tighten the gripper shaft to the coupler.
Next it's on to mounting the motor. I first have to print a new motor slip clutch coupler first as this motor shaft is a different size.
Re: Rov Reboot (3D Printed Rov)
Next it's on to figure out how to mount it to the Rov. I have some different ideas for that too I want to try...
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- Posts: 3
- Joined: Jan 13th, 2019, 1:40 pm
Re: Rov Reboot (3D Printed Rov)
Hello Steve great work.
I was wondered what type of plastic you are using to machine your end caps.
( Im very new the the lathe world)
P.S. I was hoping as a hail Mary i would be able to use solid 3D printed end caps but after 12 iterations still no luck.
I was wondered what type of plastic you are using to machine your end caps.
( Im very new the the lathe world)
P.S. I was hoping as a hail Mary i would be able to use solid 3D printed end caps but after 12 iterations still no luck.
Re: Rov Reboot (3D Printed Rov)
Thanks... The end caps on the camera tube were machined from a solid rod of PVC. This was the stuff I used https://www.mcmaster.com/catalog/125/3738 (PVC Rods 2") Any hard plastic should work though.
I tested the 3D printed parts out and yeah unfortunately even at 100% infill they will not work.
-Steve
I tested the 3D printed parts out and yeah unfortunately even at 100% infill they will not work.
-Steve