My Custom Built Camera Crane

GREAT WORK. The only part Im not to crazy about is how the head attatches to the crane. It looks a bit weird with the angle piece. But other than that little part, I love it!
 
Paul F said:
Here is a sample of my jib with no head pan/tilt movement; just jib pan/tilt. You will notice that the camera is not level when at the high point. It also wobbles a bit. This was my first test. I found out that the stabilizer that holds the head level had an interference that caused the whole head to tilt when it was up near the top. So the whole head is at an angle and wobbling around. I've fixed it, but have not run another test.

In that shot, it is going 16' high, 14mm focal length (28mm equivalent on 35mm camera)

http://www.youtube.com/watch?v=qCx0azIM1e0&feature=channel_video_title
Click to expand...

I notice a lot of wobble in lower shots as well. Sounds like the overall system needs more weight on both ends to keep from those little movements happening. As I've been studying cranes, steadyarm systems, that was the biggest thing I noticed. Many of the expensive systems that work with heavy cameras have weight that helps to stabilize movement. The OP system was REALLY REALLY smooth. I was VERY impressed by it. Can't wait to see all the electronic stuff you guys are doing. I'd also add that Kessler that makes the Revolution head sells different motors for different speeds. Looks like others are seeing the same problems you all area seeing. Also, a lot of people are concerned with noise of the motor/gear assembly as well. VERY important.
 
quick update

made a couple extra supports to stop the tube flex

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and got a package in the mail ;)

curious...
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looks like a suspicious package...
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nope (luckly)
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yay!
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lcd mount is on its way along with an extra battery, gears, motors and mini hdmi cables!
 
Here is a sample of head movement using the types of motors and gear ratios we've discussed. I am quite disappointed with the speed range, the inability to get the motors to creep very slowly, and the abrupt start and stop.

The clip shows:

An example of pan and tilt fastest speed vs motor RPM and gear ratio
An example of the slowest pan or tilt with these motors and gear ratios
The limited range between slowest and fastest
The abruptness of the start and stop due to the fact that these types of motors don't start until the controller is outputting about 15% duty cycle
A poor demo of the sound level of the motors. They are making some noise, but there was some wind making some background noise. But the motor noise is quite low. I don't think the noise would ever be an issue in an outdoor location. It could be an issue indoors.

http://www.youtube.com/user/1941taylor#p/a/u/0/LhaY-Lrbfa4

Oh, and you get to enjoy that bloody auto iris step function.
 
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Paul F said:
Here is a sample of head movement using the types of motors and gear ratios we've discussed. I am quite disappointed with the speed range, the inability to get the motors to creep very slowly, and the abrupt start and stop.

The clip shows:

An example of pan and tilt fastest speed vs motor RPM and gear ratio
An example of the slowest pan or tilt with these motors and gear ratios
The limited range between slowest and fastest
The abruptness of the start and stop due to the fact that these types of motors don't start until the controller is outputting about 15% duty cycle
A poor demo of the sound level of the motors. They are making some noise, but there was some wind making some background noise. But the motor noise is quite low. I don't think the noise would ever be an issue in an outdoor location. It could be an issue indoors.

http://www.youtube.com/user/1941taylor#p/a/u/0/LhaY-Lrbfa4

Oh, and you get to enjoy that bloody auto iris step function.
Click to expand...

paul i think you are kicking yourself for no good reason. What you have accomplished on a budget (prob the same as mine) is incredible. Once your head is moving its VERY smooth. I will be very happy with that if im able to get that kind of smoothness. On another note, after doing some more research i think ive nailed down the reason for the jerky start/stop.

The motors we are using (i assume we are using the same simple motors) are cheap. simple as that. if you look at some maxon motors. im pretty sure some of the cheaper ones are over 200 apiece. Those motors are so much more engineered to start stop at extremely low rpms. Better bearings allow the motor to overcome its own friction sooner, better balanced, more efficient electronics, lighter weight internals. brushless perhaps??? <---- i can see that making a huge difference. They use the maxon motors i believe in the proaim jib units.

http://www.maxonmotor.com/

i was also thinking, since the end result is always an edited video, you could always shoot a little wide, zoom in a small amount in post, find the start/stop point on the shot and smooth it out with some panning in edit work. either way i find most of my shots will start end while the jib is on the move. i wont need to show the beginning or ending.

would you be able to show me some videos or pics of the rig in action?
 
I've read up on the Maxon motors. Video Robotics uses a Maxon motor that costs $500. http://www.maxonmotorusa.com/downloads/Video_robotics_maxon.pdf.

Yes, we are using the same type motors.

Agreed. Planetary gears probably help. Good bearings certainly help. Brushless may help. But I've talked to a motor manufacturer (not Maxon) that makes expensive geared motors with planetary gears and bearings (brushed DC) and they got the same results in their lab; no motion until 15% PWM. So I'm thinking there is some minimum torque that needs to be present to get the motor moving. It doesn't seem to matter much what the load is.

But then I took apart a Fujinon servo lens. It has a tiny motor. About .4" in diameter and 2" long. It can creep a zoom at an almost infinitely slow rate. So there is some magic somewhere. But i want to know what the secret is. I'm willing to spend some money, but I don't want to buy 2 or 3 $500 motors trying to find the right one.

Yes, I agree that we can work around it. But of course, we always want more.

Here are some pictures of my jib. http://www.dvxuser.com/V6/showthread.php?249955-A-Configurable-Jib&p=2342433#post2342433

I'm looking forward to your project completion and results.
 
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Rick Burnett said:
I notice a lot of wobble in lower shots as well.
Click to expand...

Rick - only the first shot was the jib. The others were my first try with my new (used) Cartoni C15 head. Were you talking about those? Ughh, I need to practice.

Rick Burnett said:
Sounds like the overall system needs more weight on both ends to keep from those little movements happening. As I've been studying cranes, steadyarm systems, that was the biggest thing I noticed. Many of the expensive systems that work with heavy cameras have weight that helps to stabilize movement.
Click to expand...

I agree that weight is helpful for stabilizers; moment of inertia keeps the camera steady. But for the jib, weight is a problem. The more weight, the more rigid the system needs to be; the more it wants to flex. What I think it needs, and I would like to add, is drag, just like a tripod head. Right now, my jib is beautifully smooth and easy to move; too easy.

Rick Burnett said:
I'd also add that Kessler that makes the Revolution head sells different motors for different speeds.
Click to expand...

Very interesting. I'd like to see some shots from a Kessler to see if how far away I am from what they are capable of.


Rick Burnett said:
Also, a lot of people are concerned with noise of the motor/gear assembly as well. VERY important.
Click to expand...

Yes, there is some noise. But it really is nominal. Certainly, much more quiet than an RC servo motor. For outdoors, no issue. For indoors, it might be a problem depending upon what mic is used. You can listen to the motors in the link I previously posted. I took an MKH416T and pointed it straight at the head from 5' away. Your not supposed to aim a shotgun at the head, but I figured that was a worst-case test. The pan motor has a gear issue and is making some noise I could hear in the headphones when running at fast pan. The tilt motor is quieter and I did not hear it. The motors are much quieter at slow speeds than fast speeds.
 
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Yeah, it was the later shots. What focal length were you shooting? When I am up around 85mm on my AF100 I have the same problem, such small little touches of the camera and you see the shake. Horrible when there is wind. I'd say weight also is important on the crane for wind purposes as well, but I agree, then you have to worry about flexing. Systems like the Kessler Crane use a wire that is tightened across the whole top of the crane to lock out the flexing and it works really well.

I also thought your movements were really cool, sure I could see what you were saying, but as said, once it got going, nice! There are LOTS of videos over at Kessler about their motion control systems and they sell their motors, check this page out:

http://www.kesslercrane.com/motors-s/111.htm

If you are happy with their performance, you might consider one of their motors to work with.
 
Most interesting. I'm not quite sure what you have in mind, but I don't think it will do what you want. Here is what I'm thinking it could be used for:

Of course, gyros are used to stabilize camera platforms, but I wonder if anyone has done it for a simple jib setup. What the gyro could do is eliminate the need for the stabilizer bar on the jib; meaning you would only need one crane arm. Put the gyro on the camera platform. Connect it to the tilt control. Then, if the jib tilts up, the gyro would sense it and send a signal to the tilt control to correct for the tilt and keep the platform level. Cool.

The problem is that the helicopter gyro is designed to work with a servo, not a motor. So your back to using servos, which will not do what you want, as you already discovered. BUT, the idea of using a gyro to control a modestly priced crane/jib platform is very intriguing. I'm going to do more reading. Eliminating the guy-wire stabilizer on my jib is interesting. It's way more expensive, but I still find it worth looking into if just as a learning exercise.

Was that what you had in mind or were you thinking of something else?
 
well ya sort of but i was thinking, if u are using the gyro to maintain a horizontal platform for the camera, whats stopping you from putting it on both axis? vibrations, bumps and so on could transfer unwanted movements to the vertical and horizontal pan/tilt of the head. The gyro would counteract those movements and keep the camera level and steady. of coarse you would need a suspension setup to absorb the up down movement of the head. The principal stays the same.

Gyro senses movement not instructed by user = Gyro sends signal to motor/servo to counteract and cancel out unwanted movement.

I see that the gyros i was looking at are for servo use. I dont see how it could be any different replacing the servo with a motor. Both require an electrical signal, both end up turning something. If those dont work im sure there are motor gyros out there...

il finish my head and take the unit down to the hobby shop and try out one of those gyros on the spot.

holy crap
http://www.youtube.com/watch?v=DWMj3stolpQ&feature=related
 
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Great. A wireless head will be cool. When might we see it running? If you get that bugger to have nice speed and start/stop control, I'm going to have to switch to your setup.
 
im waiting on the motors and gears. as soon as those parts arrive il be fabricating mounts and so on as quickly as possible.

although il be able to test motor speed as well as start stop pretty much right when they arrive. - should be this coming week.
 
Looks great Jeremy. Well done. You should be pretty happy with the results.

How happy are you with the motor control? It looks like it worked well. I thought I saw you use the pan, but no tilt.

What is the suspension for?
 
Paul F said:
Looks great Jeremy. Well done. You should be pretty happy with the results.

How happy are you with the motor control? It looks like it worked well. I thought I saw you use the pan, but no tilt.

What is the suspension for?
Click to expand...

i actually didnt have the motor rig built in that video, i was just manually whipping the head around myself.

suspension is for truck mounted video, i will need a buffer between the camera and the truck. but i redesigned it.

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