alphapepper
USA
Asked
— Edited
Hi folks,
I've searched this forum and found some information related to my question, but I'm still experiencing some problems.
The vertical on my pan/tilt camera set-up is having some problems. It still bobs and flops up and down. Sometimes it locks in an up or down position. I don't know if the blue servo just isn't strong enough, or if there's a problem with my set-up.
I replaced the horizontal blue servo with one from the EZ kit, because the first seemed too flimsy. The horizontal tracking for face and color works great.
I uploaded my project file in-case anyone has time to investigate. But it seems fairly simple. I attached a picture of my set-up too. Many thanks!
My1stEZRobot.EZB
Follow these instructions to upgrade...
1) Load ARC
2) Load your project
3) Change your camera resolution to 320x240
4) Save your project
5) Close ARC
6) Upgrade ARC, Download and Install a more recent version
7) Load ARC
8) Load your project
Now, as for your Y axis camera tracking issue... You may need to use the Invert option, but i'm uncertain of that yet. It depends on the direction that the camera moves when it tracks the object.
Also, check the servo port is correct. The Y axis servo is specified for D1, and the others seem to be D17, D18, and D19.
The little servo is fine for the weight. They do break easily if you force their movement by hand, or move past their limit. Always use the servo Calibration tool (found in the tutorial) when attaching things to a servo. The servo Calibration simply centers the servo, so you can predict it's limits.
If the is "flopping" the weight, perhaps one of the gears inside is stripped. If the servo is "moving" toward a direction and holding it's weight, than it's most likely a configuration issue.
Poor lighting is usually an issue with face tracking.
Also, I'm starting to get away from mounting the camera on the servo. I'm starting to mount the camera stationary and use the "Relative Position" option in the Camera Config. Who says robot's need their eyes on their head?
I know I paid next to nothing for my little blue servos and suspect they may be of a lesser quality than what is suggested on the label... in other words, cheap Chinese knock-offs.
The TG9e should have 1.5kg/cm of torque so should be able to tilt the camera in the housing.
If all settings are correct and lighting levels OK check the power supply is providing the EZB with enough voltage and check the bracket isn't stiff to move - I had a similar bracket which was rather stiff when I put it together (I expect I put it together wrong).
Also, not sure if i need to tell you this... but Movement and servo tracking both enabled will not work. Moving the head while moving the body is impossible to do together... Unless Relative servo tracking is used with a stationary camera.
I can assure you that once you have adjusted the grids, specified the min and max positions, adjusted the object color brightness... that it just works - like magic
What object are you attempting to track?
If you're sitting very close to the camera, some objects won't be tracked because they are too close. For example, if you hold a basketball in front of my face, i have no reason to move my eyes or my head to look at it - because it's right there in front of me
I hope that's making sense
simon
The tilt servo on D17 (the Y axis) does not work as well. If I manually control the servo (via a vertical servo control element in ARC) I can move the head up and down pretty well. When the servo has to tilt during camera tracking it will move a little bit up to track an object but that's about it, then it pooters out and won't tilt up or down. Also when setting the min-max values in the camera control for D17 the tilt servo I can make the servo move to the extremes, but not back to a middle position. For example say I set my min position to 10 and my max to 90, but then change the max to 50 the servo does not go back up, it just make noise like it's trying.
But, if I switch to a vertical control servo element I can make the tilt servo move up and down and back to center.
My gut tells me the issue is in the 9g blue servo.
Those 9g servos aren't all that strong. Pan will be fine but lifting anything, you may struggle.
Try an MG90 (or similar) and see if that's any better.
I would agree with you, pan works great, tilt is a little weak. BUT.....
I took a fresh start at the Pan/Tilt camera controls, re-tested the servos for centering and re-adjusted the grids via a ruler and low and behold my little bot is tracking my face and blue wire guard and motion like a champ.
Redoing the grid layout helped a TON. Eyeballing it I thought I had the grid in 3rds but when I used a ruler I could see I was very uneven. I vote for AutoGrid in the next release
Setting up the camera will help a lot with tracking, as will servo speeds. Mine are set to 3 which makes it smooth but experiment, you may need 2 or 4 or maybe something way different.
You could just power the blue ones with 6V to see if that helps (if they go bang don't blame me though, I haven't tested or looked them up to see their voltage ratings).
Yes, all of my servos are now externally powered to save from browning out. It's a little more work, a little more wiring and a bit more hardware but it's worth it in my opinion.