The Craftmans Shop > Radio Control Models
Bruder Manitou 2150 - RC conversion
ddmckee54:
Well, I’ve got good news and bad news.
The good news is that all the parts have come in so I can start experimenting with the 6050 IMU and my Nano clone, to see if I can work out an auto leveling system for the Manitou.
The bad news is that last night I did some drawing to determine how much of a pitch and roll angle the crane could be at and I would be able to level it using the outriggers with no blocking. Turns out it’s not so much. I’ve attached a JPG of the 3D PDF since some people seem to not be able to view the PDF.
In its’ current configuration the outrigger pad, circled in brown, will extend about another 3” to the right, actually 77mm for those of you that are Imperially challenged. The outrigger will pivot around the location circled in blue. The outrigger assembly is driven up and down by the ram, the yellow part right above the outrigger. The ram will have about 3/4” of travel, call it 20mm. This translates to about a 1-1/4”, call it 30mm, vertical travel of the leveling pad. In itself, this is not bad. However there’s almost 1” of ground clearance to the leveling pad, call it 24-25mm, so there’s less that 1/4” of actual vertical movement before the ram reaches the end of its’ stroke. I’m going to have to either use blocks almost all the time, or I need to redesign the outrigger rams.
I think I’ve got 3 options on the redesign:
1) Raise the ram motors a lot – maybe 20-25mm! I don’t know if I’ve got room to do this and still clear the molded in counterweight.
2) Move the ram motor assembly from centered on the outrigger to the far side of the outrigger. The far side would be away from the 2 outriggers. This would allow me to move the point where the ram attaches to the outrigger from the top of the outrigger to the bottom. This would give me approximately an additional 20mm of ram travel. The additional ram travel would give me an additional 30mm of vertical travel on the pad. The problem with this option is I’m not sure I’ve got enough clearance between the wheel and the outrigger for the ram.
3) Move the ram motor assembly from centered on the outrigger to the inside of the outriggers. The inside would be between the 2 outriggers. The problem with this option is I’m not sure where the ram would be in relation to the outrigger extension motor.
If I can get another 20mm of ram travel, that translates to 30mm of vertical movement for the leveling pad at full extension. I could lower the leveling pad about 1-1/2". Which if I measured it right means I would be able to correct for a +/-13° roll angle and/or a +/-9° pitch angle on the crane.
Don
WeldingRod:
Move the blue circled pivot point inward?
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ddmckee54:
WeldingRod:
That might help, what might help more is dropping the outriggers down so that they're even with the bottom of the axles. This would move the pivot down not in. That would effectively give me 10-12mm more of vertical travel just by eliminating some of the ground clearance under the outriggers. But it wouldn't be eliminating any of the crane's ground clearance since the axles are that low already. When you add in the additional 10-12mm of ram stroke that would give me I'm probably close to the 1-1/2" movement that redesigning the ram placement would have given me - with a lot less hassle.
It's a change from the Bruder original, but they were designed as toys - not scale models. I can live with it.
Don
ddmckee54:
I looked at the model last night, both the 3D version and physical one, and I came to the conclusion that my options 1-3 will NOT work. I can't raise the outrigger ram motor, option 1, because that will interfere with the crane counterweight as it swings around. I can move the rams to what I called the outside, option 2, because that will interfere with the fenders and wheels. And I can't move the rams to the inside, option 3, because that will interfere with the outrigger extension motor.
WeldingRod suggested moving the outrigger pivot point in, and I thought about that, but I wasn't sure if that would be a help or a hinderance. It did get me to thinking about moving things though. Last night I played worked with the 3D model and lowered the outriggers 11mm so that the bottom of the outrigger was even with the bottom of the axle.
That way I can accomplish several things. I don't lose any ground clearance on the model, I reduce the amount of travel between the UP position of the outrigger and the ground, and I extend the outrigger ram - giving me more travel on the ram. I'm gonna give WeldingRod the blame credit for this idea. I've attached a screenshot of the revised 3D model. Ignore all the extra crap - I forgot to turn it off before I saved the PDF last night.
The second attachment is a HIGHLY simplified front view of the Manitou. Can’t see it? Well, at least all the important bits are there anyway. The white rectangle at the top is the upper frame of the crane. Below the upper frame is the outrigger, it is shown in with the outrigger fully extended, The horizontal line that runs all the way across from one side of the screen to the other is the level “ground”. The vertical line on the left is the outside of the tires on that side.
Inside the orange blobby-circly-thingy is the outrigger pivot point, this point never moves with respect to the upper frame.
Inside the magenta blobby-circly-thingy is the outrigger ram lower pivot point when the ram is retracted, the angled white line is the ram centerline when retracted. The small white circle to the upper-left of the magenta thing is the outrigger ram upper pivot point – this point never moves with respect to the upper frame. The green circle shows the path the end of the outrigger ram would follow as it is swung around the ram’s upper pivot point. The cyan circle shows the path that the ram’s lower pivot point will follow at the outrigger is swung around it’s pivot point. The white line, the green circle, and the cyan circle all conveniently intersect at the same spot, the fully retracted position of the ram.
I determined that the outrigger ram has 27mm of usable travel. Offsetting the green circle 27mm. and I get the red circle. The stuff shown in green is with the ram fully retracted. The stuff in red is with the ram fully extended.
The tan blobbish thing on the right contains the simplified outrigger pad, that’s the green inverted T, the pad pivot point, and line that shows the center-to-center distance between the pad pivot point and the outrigger pivot point. The large white circle is the path the pad pivot point will follow as the outrigger ram extends and retracts. All this crap just to get a couple of angles, and we’re still not done.
Where the red circle and the cyan circle intersect will be the position of the outrigger ram lower pivot point when the ram is fully extended. Looking at this in the light of day I can see I made as boo-boo 19.6° does NOT equal 19.21°. I think I know where I screwed up, when I changed the angular dimension style halfway thru the drawing - I changed it from X° to X.XX°. I measured the angle between the two green lines so I could determine where the pad pivot point would be with the ram extended. It measured 5°, but it was actually 5.39° - I just measured it. That means my measured maximum pitch&roll angles will slightly too small, probably by less than ¼ - ½ degree.
OK – focus! Back to draining the swamp. With the pad pivot point‘s lowest position now fixed we can find where the pad touches the ground, the red inverted T.
Assuming that the crane will pivot on the outside of the tire, we draw a line from that point to the pad’s assumed contact point and measure the angle. VIOLA, we get 9.11°-ish, remember I makada slight boo-boo way-back-when. That’s the maximum roll angle I can hope to correct without blocks. The vertical line on the right represents the distance between the front and rear outriggers. When I connect the dots and measure the angle I get 7°-ish degrees as the maximum pitch angle that I’ll be able to correct without blocks.
I actually thought it would be more, but numbers don’t lie.
Don
ddmckee54:
I was looking through this thread from the beginning, and WAAAAYYY back in Post#9 I found that WeldingRod had suggested this...
--- Quote from: WeldingRod on November 21, 2019, 09:08:13 AM ---You could set the legs up to go to fixed positions one at a time. Or, if your insanity knob is broken off, you could make it self leveling ;-)
--- End quote ---
WeldingRod are you physic or sumfin? I think the insanity knob has been turned way past 10 to maybe 15, or 25.
The current plan is for the Arduino to extend/retract, raise/lower the outriggers. To do this without breaking anything I'll need at least a fully retracted limit switch for outrigger extension. I think I can get by with just timing the extend, I'll just have to find the maximum safe extension time. I'll use the fully retracted limit switch so that the outrigger will always be starting its' extension from a known position. I'll need a full up limit and a full down limit for the outrigger raise/lower ram so I don't break anything on it. That's 3 limit switches per outrigger or 12 total for all the outriggers. When you add in the I/O for the lights and communicating with the radio this is WAAAAYYY beyond an Arduino Nano, probably need to go with a Mega.
I'll start the auto leveling sequence by leveling the back of the machine. I was going to start at the lowest corner, but then I realized the rear axle is fixed, while the front axle pivots. If the lowest corner is at the front of the machine and I try to correct the roll angle, then the machine has to pivot on ONE of the rear tires - putting a lot of stress on things. I know, this is a MODEL and the stress will be minimal - but still... Anyhew, lower the high side rear outrigger until the roll angle changes, then lower the low side rear outrigger until the roll angle changes. At that point both the rear outrigger pads are on the ground. Continue to lower the low side outrigger until the roll angle is 0° or at least crose-enuf, or until we hit the outrigger max down limit - which-ever comes first. The low side outrigger will also need to be slowly extended as it is being lowered to keep the pad in approximately the same spot. The end of the outrigger swings in arc as it is lowered which will try to pull the pad closer to the machine - can't have that. (We gots an Arduino, it can keep track of such trivia so we don't have to worry about it.)
Next we lower the front outriggers until they touch the ground. I was planning on lowering one at a time until I saw a change in the roll angle, but with both the rear outriggers planted firmly on the ground I don't think it's going to want to roll much, won't know until I get a test rig built. It'll probably be best to look for a slight change in pitch angle, the outrigger will be lifting the machine after all. Do this for both sides up front.
Once both front outriggers are on the ground we determine from the pitch angle if we're nose up or nose down. If we're nose up then lower and extend both of the rear outriggers until the pitch angle is crose-enuf to 0°. If we're nose down, then do that to the front outriggers instead. We may have to do some correction to the roll angle as we are correcting the pitch angle, but that's for later when we decide to get elegant with this instead of just hitting it with a 2x4 to make it work. Same for alerting the operator that it's too far out of whack to do an auto-level without some help.
I need to do some more digging into the 6050 IMU that I'll be using for the pitch and roll sensor. I need to find out when it initializes, whether it's on power-up, or if it's on command. I think that the pitch, roll, and yaw angle offsets are determined on initialization - and all angles are based on those offsets. I seem to remember one video where the unit was initialized and then yawed 90°, the IMU was showing what was actually a pitch angle as a roll angle, and vice-versa. If it initializes on command then I'm golden as I intend to keep this thing brain-dead until I tell it to level. If it initializes on power-up then I'll have to do what the quad-copter guys do and correct the pitch and roll angles based on the yaw angle.
Meanwhile back at the ranch, I need to figure out what I'm going to use for limit switches, and where I'm going find room to put them. I'm going to need to get plenty of inspirsation from Mick thebass, and the rctractorguy. Mick does Bruder conversions, check out his YouTube channel. https://www.youtube.com/channel/UCbTqmHlFmasSVFomeuu0hsQ He has no problems putting 10 pounds into a 5 pound sack.
The rctractorguy converts 1/32 scale die-cast tractors and equipment to RC, and that's more like putting 25 pounds in a 5 pound sack. This is his channel.https://www.youtube.com/c/rctractorguy
I wanna be just like those guys when I grow up, right down to the cool accents.
Don
I know, I know,,, No pictures so this didn't really happen, but there's been a LOT of skull-sweat involved, does that count?
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