Gimbal BLDC Motor with InstaSpin

that URL is not working

if this is a direct drive motor, where a rotation of the shaft gives the same rotation of the gimbal, then you need a mechanical rotor sensor, at least Hall sensors and usually an encoder or resolver for more accurate position

if the motor is geared down, where you run the motor shaft at a higher speed and the gimbal moves slowly, it could be possible to do sensorlessley (without a mechanical rotor sensor) but it depends on the gearing and accuracy you require. Especially dealing with start-up and if any backwards rotation of the rotor shaft is allowed at any time.  I would think this would be challenging for a gimbal applications.

Hello Chris,

Can you please try this link below.

http://www.iflight-rc.com/product/iPower-Brushless-Motor-iPower-GBM-Series-iPower-Gimbal-Brushless-Motor-GBM4008-150T.html

This is the BLDC motor we are going to use and the sensor we have selected is AS5045B

http://www.ams.com/eng/Products/Position-Sensors/Magnetic-Rotary-Position-Sensors/AS5045B

Please let me know your thoughts and suggestion on this.

Tushar

it certainly appears that this will be used as a direct drive, the camera directly mounted to the outer rotor and moving in syncronization with the rotor.  this is very unlikely to be good enough to do sensorlessly today just with FAST.  This looks like it has a fair amount of poles, so assuming you have proper resolution you might be able to run in the 1 Hz range.  This could get you into the ~10 RPM range, but not sure that's slow enough. Also as mentioned the initial start-up of movement each time may not be good enough.  I would give it a try though. Some recommendations.

1. When trying slow speed go ahead and multiply the current control Kp values by 4x (by default they have a 0.25x factor included, so essentially remove this. You'll see this in the calcgains function starting in lab05a)

2. For best performance use InstaSPIN-MOTION SpinTAC suite. This will let you tune the speed controller much better than the PI controller in FOC. 

Worst case you can use InstaSPIN-MOTION proj_lab12 for sensored feedback.  Solution is completely achievable using a sensor, no question.

Thanks Chris for your reply.

I will explain in detail the whole idea of our project.

we need to control Gimbal Motor using Wireless Network possibly WiFi.

1) we will be using this motor with gear ratio of 13:64 (not a direct drive)

2) The motor will updated with 30 times per seconds

3) The encoder sensor we will be using is AS5045B (Please give comment on this sensor)

4) The commands to the C2000 control card will come through serial interface(SPI/UART/USB)

5) we will be using  DRV8312-69M-KIT for testing purpose.

Questions

-> Can these gear ratio would provide enough precise and stability.

-> Is this sensor encoder enough for our application.

->  Is there any demo project which we can modify so that we can input command or data to C2000 control card which it can process to control motor.

P.S. : You can always suggest some changes or modification with this design

Tushar

Thank you!