Breezemont
Member
I don't know - I did some preliminary experiments with it, but dropped it once I saw the brushless DD gimbal potential.
General Camera mount theory (open discussion)
- Thread starter DennyR
- Start date
aerialshots
New Member
This would have to be one of the most interesting threads I have read on a forum yet, I prefer to fly without tilt and roll servos trying to control a heavy camera on a gimbal. I am just one of those pilots that cannot stand a heavy DSLR swaying underneath, I just fly better throwing a large Octo around the sky knowing there is no servo to seize or break and overload the MK FC board which we all know that means everything returns to the ground very quickly. Obviously I am only talking about still photos here, I know the more expensive gimbals would work the best and if the servos are fast enough it cannot "sway", but check my website aerialshots.com.au , every photo on there is taken with a Nikon D5000 secured by velcro on a rigid aluminium frame below a MK Octocopter. The standard 18-55 mm lens has VR, (vibration reduction). The aluminium frame is only held by 2 velcro straps, the weight of 3 Lipo batteries attached to the aluminium frame reduce vibration even more. 90 percent of photos are clear and sharp, The only problem I have is on high wind days when the Octo is leaning into the wind I lose part of the horizon, that is a matter of levelling the photo in photoshop. But does anyone know of a camera that can keep the horizon level without having to have a heavy gimbal system to keep the whole camera level ? Only other way I can think of is having the Octo always level and using a motor and prop mounted on a 360 degrees servo to draw the octo into the direction you want to go, that way the multirotor never leans or tilts, bit extreme but it might give someone a idea.
View attachment 12140
View attachment 12140
Attachments
It is some time since I was able to contribute anything to this thread but I think what I have here should be of interest to those who have a willingness to take the bull by the horns and make their own gimbal. First a little history. Before the brushless gimbal there was the servo driven gimbal and then I came up with the brushed indirect drive gimbal. Eureka It looked a bit messy but at last the technology was there to produce cineflex performance at a sensible price. Well whilst contemplating how could I produce it in this part of the world along comes DJI with another solution based on different electronics and motors. Just as we all thought that was it, along comes Alex with something really clever and so cheap. I'm so glad I did not invest in my production Indirect drive brushed solution. which worked on a similar principle.
So what is next ?Well IMHO this is it. THE BRUSHLESS INDIRECT DRIVE GIMBAL
Basically it is a brushless 3 axis board with a 4-1 and a 5-1 reduction gear on the motors. This is what I used with my Brushed gimbals and it has a few advantages over direct drive. The main one being that it is much more powerful and is less effected by balance and other issues that can knock it out os sync. So, direct drive for your GoPro's but if you want to move a heavy DSLR or Red Epic then this is better.
The images below are of a prototype drive unit for the pan axis. Powerful and accurate with the alexmos board but the Martinez just didn't cut the mustard as it just does not yet have the refinement of the Alexmos software to adjust for the different parameters. I am running 5-1 on the roll and the pan and 4-1 on the tilt. Don't worry about the speed of response, it is still blisteringly fast. Gain values can be doubled.
One aspect that I thought the likes of DJI and indeed just about everybody else would pick up on is the pan axis function as a means to rotate the image through 90 deg. so that a portrait shot can be tilted downwards. When I hear people banging on about the relative pixel counts of Canon Vs. Nikon etc. These are the same guys that have to crop the sides out of a landscape image. Why is this important, well that is simple as most publications are sold in portrait format. I got around the electronics problem by having an imu on each axis, What you have to consider is that what you see from the cameras point of view is still the same. In terms of movements. For example a pan movement on a Zenmuse will track a curve on the ground when it is pointed down at 45Deg. but with my system it will be a straight line. View attachment 12212View attachment 12213View attachment 12214 but now with 6 and 9 DoF imu's it is no problem
If you have the pan axis on the camera base plate as opposed to the first motion axis then all that is possible and for less weight gain.
So what is next ?Well IMHO this is it. THE BRUSHLESS INDIRECT DRIVE GIMBAL
Basically it is a brushless 3 axis board with a 4-1 and a 5-1 reduction gear on the motors. This is what I used with my Brushed gimbals and it has a few advantages over direct drive. The main one being that it is much more powerful and is less effected by balance and other issues that can knock it out os sync. So, direct drive for your GoPro's but if you want to move a heavy DSLR or Red Epic then this is better.
The images below are of a prototype drive unit for the pan axis. Powerful and accurate with the alexmos board but the Martinez just didn't cut the mustard as it just does not yet have the refinement of the Alexmos software to adjust for the different parameters. I am running 5-1 on the roll and the pan and 4-1 on the tilt. Don't worry about the speed of response, it is still blisteringly fast. Gain values can be doubled.
One aspect that I thought the likes of DJI and indeed just about everybody else would pick up on is the pan axis function as a means to rotate the image through 90 deg. so that a portrait shot can be tilted downwards. When I hear people banging on about the relative pixel counts of Canon Vs. Nikon etc. These are the same guys that have to crop the sides out of a landscape image. Why is this important, well that is simple as most publications are sold in portrait format. I got around the electronics problem by having an imu on each axis, What you have to consider is that what you see from the cameras point of view is still the same. In terms of movements. For example a pan movement on a Zenmuse will track a curve on the ground when it is pointed down at 45Deg. but with my system it will be a straight line. View attachment 12212View attachment 12213View attachment 12214 but now with 6 and 9 DoF imu's it is no problem
If you have the pan axis on the camera base plate as opposed to the first motion axis then all that is possible and for less weight gain.
Attachments
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None at all, It has to be well engineered with no backlash and much better than belt drives in my experience. Those gears came from servo city many years ago. they are a good gear form that can mesh tightly without any play. An old trick is to mesh them on the tight side and then run em on metal polish. cleaning them well afterwards.
Instrument brgs. in that bearing post. which incidentally must be balanced with the camera attached. (Z Axis)
Instrument brgs. in that bearing post. which incidentally must be balanced with the camera attached. (Z Axis)
Last edited by a moderator:
CrashMaster
Member
AeroXcraft in the UK have achieved balance and reliability with their VTR gimbals specificly built for the GoPro and the NEX5N. They are full ball-raced and belt driven from servos and can be stabilised by either the AC controller or HoverFly Gombal controller.
I can vouch for the VTR-GP GoPro 3 version as I have one. They are very stable but as suggested the heavier the load being moved the more opposite action on the gimbal and craft is exerted. Mounting a Nex5 puts over 3 times the weight of a GoPro into action and a Canon 5 even more. It is worth looking at their set-up as it is very simple, robust and very effective. Getting around the servo jitter by using the servo to power a cogged ball raced wheel rather than directly attached to the servo making the tension load on the wheel baring and not the servo's.
I can vouch for the VTR-GP GoPro 3 version as I have one. They are very stable but as suggested the heavier the load being moved the more opposite action on the gimbal and craft is exerted. Mounting a Nex5 puts over 3 times the weight of a GoPro into action and a Canon 5 even more. It is worth looking at their set-up as it is very simple, robust and very effective. Getting around the servo jitter by using the servo to power a cogged ball raced wheel rather than directly attached to the servo making the tension load on the wheel baring and not the servo's.
SamaraMedia
Active Member
I'm using a Futaba T8FG with the H3-2D and can get the tilt function to work properly but can not get the manual speed control to work. No setting seems to slow it down and the default is way to fast to do a quick slider move and get a slow and steady motion. I've tried everything I can think of to get it working like when I first purchased it over a year ago but it seems like through one of the updates the ability to slow down the tilt speed has proved elusive at best, very frustrating on what otherwise is a nice unit. I have it mounted on a DIY quad I made, not a Phantom. I have not messed with the gains for pitch and roll since that I thought was just for the gimbals reaction time for response in air. I'm connected using s-bus. I've tried turning off the gimbal control but then I can't make any adjustments to the speed control. Suggestions?
Thanks, John
Sent from my iPad using Tapatalk
Thanks, John
Sent from my iPad using Tapatalk