Goes the Monkey V3.0
I think this will be the next-to-last version of
this robot. I decided on the general principal in version 2
and decided to improve on it and make it more reliable. I used
Solidworks to design the
basic pieces and layout of the robot. The goal is to have this
ready for Robothon in early
October but the 12lb robot is taking priority. This version
has AL side and wedge struts as well as .04 Ti armor for the sides
and the front wedge. I think it is still a bit big for all of
the components but I'll find that out when I put the thing together.
If things go as planned I'll be able to use this design to make
minor refinements and hopefully have thicker TI for the wedge for
the "final" version.
Solidworks picture of the robot. The rear of the pneumatic arm
has been moved to fit above the motors to reduce the overall length
of the robot a bit.
Solidworks the robot base (entire body + motors and wheels) comes in
at 2 pounds. In a prior version of the robot the pneumatic
system came in at 10oz, so this should leave about 6oz for
batteries, wiring and the receiver. I'll have to find out when
it's done but I think it should come in at about 3 pounds when it is
done. Hopefully I don't have to do much "lightening" of the
robot to have it make weight.
still uses the relatively heavy Lynx Motion motors but since I
already have many of them and the weight seems to be ok I decided to
stick with them. If I can't reduce the weight by an oz or two
in the next version I'll probably go with smaller motors to beef up
the front wedge. .04 Ti is likely to get penetrated by some of
the bigger spinners.
I managed to get the regulator and 12gram CO2 tank to fit crossways
in the robot, near the motors and underneath the pneumatic cylinder.
This has freed up a lot of room for the rest of the components.
I think I'll be able to further narrow the front part of the bot in
a future version.
The entire front
wedge should flip up. It is difficult to say how high it can
throw another 3 pound robot but it should be more than sufficient to
turn them over. We'll see if I need to add a self-righting
horn onto the wedge like I did for the 12lb
Goes the Monkey V2.0 (No pictures available)
I didn't get any pictures of this version, but it
competed at da vinci days in 2005. It was a more basic design
with the wheels in the back and a flipping wedge up front. It
went 1 and 1 in the competition and the basic design seemed very
promising. It served as an inspiration for
Goes the Monkey V1.0
- Mostly made of HDPE and Garolite
- Titanium Wedge on the front
- Big-Pneumatic Pop! I'm trying
to make the weapon have as much bang as I can get. My initial
estimates is that it will be able to throw another 3lb bot 18" into the air.
I'm going to play around with the arm geometry to see if I can get this
- About 1lb dedicated to the pneumatic
system (not including the arm)
Most of the pneumatic parts arrived a few days ago. Last night I had a
few hours to myself and was able to put the parts together to see if
it works. The pneumatic cylinder seems to have a lot of speed
and force behind it but it is difficult to say since it doesn't have
any load on it. I got about 75% done with creating a flipping
platform to test out different arm geometries. Hopefully I can
get it done by this weekend and start throwing things around!
By drilling different holes in
the arm and wood pivot base, I can try out different arm
I finished the flipping platform and tried out a few different setups.
I didn't design it very well so it isn't as flexible as I'd like. Also, I
was having problems with the regulator and the valve. I don't have the
fitting to attach the pressure gage yet, so I wasn't sure what PSI it was
running at. If I put it up to high, the valve wouldn't work, too low it
didn't have very much pop. The fitting should arrive soon so I can fine
tune it. Overall the current setup is functional but not very exciting.
It threw a 3 pound block of iron about 3 inches above the tip of the arm, which
reaches about a foot in the air. So ~15 inches total, which is more
than enough to tip an opponent over, but it doesn't have much exciting flip
power. I'll have to see if I can improve things. The current weight
of the pneumatic system is 10oz... I still need to add the servo for
the toggle valve + the mounting of the components. It should
be easy to come in under the 1 pound that I had figured for the
Close up of the 5/8"
Close up of the CO2
cartridge and regulator
It looks like there will be a BBQ on June 18th at Fergs place so I
need to get this puppy built!
The adaptor to fit the pressure
gage to the system arrived, and after some messing around I finally
got it to work ok. I had to use some Teflon tape to seal up
the connection. Without the tape, the fitting slowly leaked
air and prevented the pressure from properly building up.
Also, I may be having a problem with the regulator. Sometimes
it seems to fail to deliver any pressure to the system. I have
to slightly loosen, then re-tighten the cartridge to get it to work.
I'm not sure what is going on. It may be the rubber seal is
deforming and blocking the CO2.
|More Pictures Soon
I am tired of waiting for the SolidWorks program to arrive, so I
decided to do it the old fashion way, with graph paper. After
designing what the arm must look like and what the body must look
like to contain the components yet be as small as possible to save
weight, this thing will look weird. I'll post a picture of the
detailed drawing, but I drew up a rough sketch in Paint. With
the arm mostly above the body of the bot, I should be able to
enclose the internal components pretty well and keep the bots body
fairly stiff. I'm off to buy the UHMW today!
|Sunday June 5th
I spent some time this weekend on
the robot. I'm hoping I can get it done in time for the June 8th
BBQ. The HDPE plastic was fairly easy to cut. I cut out
both of the side walls, and the arm. The arm is a bit rougher
that I would like but it should do. This is a version 1 bot,
so I'm not expecting it to be perfect. The good news is that I
messed up the weight calculations for the sides and arm, and they
came in about 2 oz less than what I was expecting. I may
actually have enough weight to put a magnet on this monkey.
|Here is a picture
of the mounted valve. It was actually easier to do than I
expected. The plastic mount will be easy to attach to the side
of the robot. The top of the mount is likely to stick out the
top a bit, but it shouldn't be a problem. With the orientation
of the switch and how the servo needs to be mounted to activate it,
I'm more worried about the hose sticking out.
One thing I did discover with more testing is that the single-barb
hose connectors aren't really adequate for the higher pressures that
I'm planning on running things. Every little movement of the
hose causes a small (but temporary leak). I've ordered a bunch
of 3-barb connectors which are longer and should provide a better
|I couldn't get a
clear picture of this, I need a better camera for close up things.
This is the servo arm that will be mounted next to the valve.
I haven't tried it out yet, but I think the servo will have more
than enough torque to move the valve. If things are difficult
I can always use a bigger servo.
Sunday June 12th
Here is a picture of the internal layout. The CO2 cartridge
has a plastic cradle that it's base fits into, then a couple of
cable ties to secure it down. The servo is mounted to the base
and easily activates the toggle valve. In this picture the
electronics aren't yet secured. There is going to be a bit of
a wire nest inside the bot but It shouldn't be too bad to secure
them down with some cable ties. After some measuring problems,
I also managed to get the drive motors mounted and wired up.
The offset output shaft and non-symmetrical mounting holes made it
difficult. I need to make sure I have more caffeine on the
is a profile picture of the 80% complete bot. It drives around
and I can activate the cylinder. The arm seems to return to
the down position most of the time, but I still need to add some
sort of elastic retract. Also, when the arm is activated, the
bot pops onto it's back and turtles. I need to add some sort
of bar to the back to prevent it from becoming immobilized by it's
own flipper. I originally had a Garolite mount for the flipping arm
fulcrum but it broke under the stress of the flipper so I replaced
it with a huge hunk of aluminum.
Currently the bot is 7 oz underweight, and that is with the HUGE
battery 1350mh Li-poly battery that I'm using. I may go buy a
smaller one to save on weight and to more easily fit it into the
bot. There are still quite a few little things I need to do to
get it ready, but the main thing at this point is to make the foot
for the arm. I'm going to cut back the
Garolite base a bit and fashion a metal foot to attach to the arm.
Overall the arm shape isn't quite right, so I may end up making a
new one if this one doesn't hold up well in testing.