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Lucien Renaud 2022-05-25 19:07:22 +02:00
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@ -6,7 +6,7 @@ The aim of this project is to be able to use the 3-axis DJI gimbal with a custom
<img src="docs/working.gif" height=250> <img src="docs/working.gif" height=250>
## Pinout identification ## Pinout identification
The Gimbal is composed of a flex PCB with a main connector and 3 smaller for each motor. The main end connector is a 40-pin mezzanine board to board connectors. In order to work easily I have designed a breakout board which open to a 2.54" header. The Gimbal is composed of a flex PCB with a main connector and 3 smaller for each motor. The main end connector is a 40-pin mezzanine board to board connectors. In order to work easily I have designed a breakout board which open to a 2.54" header. (Kicad folder)
Here is the strategy I followed to find the pinout: Here is the strategy I followed to find the pinout:
1. Find all equipotential pins with a multimeter set to continuity tests, and test all the combinations 1. Find all equipotential pins with a multimeter set to continuity tests, and test all the combinations
@ -33,7 +33,7 @@ Each motor is composed of two ratiometric linear hall sensors. (Texas Instrument
<img src="docs/Hallmotor.jpg" height=300> <img src="docs/Hallmotor.jpg" height=300>
Ratiometric means that the output signal is proportional to the voltage supply to the sensor. In this setup, with 5V supply, the output measured is between 520mV and 1.5V, so a 1V amplitude. Ratiometric means that the output signal is proportional to the voltage supply to the sensor. In this setup, with 5V supply, the output measured is between 520mV and 1.5V, so a 1V amplitude signal.
### 2. Measures ### 2. Measures
@ -101,6 +101,5 @@ To achive position control it is necessary to have first, a velocity controller
![Closed loop position diagram from SimpleFOC](docs/angle_loop_v.png) ![Closed loop position diagram from SimpleFOC](docs/angle_loop_v.png)
However, the motors of the gimbal have hard stop and can only rotate of around a half turn. It was so necessary to remove these mecanical stops. I drilled with a 1.6mm drill the two little holes to remove it. Then the motor was able to rotate freely and PID can be tuned. However, the motors of the gimbal have hard stop and can only rotate of around a half turn. It was so necessary to remove these mecanical stops. I drilled with a 1.6mm drill the two little holes to remove it. Then the motor was able to rotate freely and PID can be tuned.
<img src="docs/drilling.jpg" height=250> <img src="docs/freeturn.gif" height=250> <img src="docs/drilling.jpg" height=250> <img src="docs/freeturn.gif" height=250>