diff --git a/README.md b/README.md index 5bf313c..ea7c874 100644 --- a/README.md +++ b/README.md @@ -8,14 +8,12 @@ The aim of this project is to be able to use the 3-axis DJI gimbal with a custom ## 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. - - 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 2. Group remaining pins by motor With the multimeter find all the pins connected to the motor connector. (Reapeat 3 times for the other connectors) - + ### Open-loop control @@ -41,12 +39,11 @@ Ratiometric means that the output signal is proportional to the voltage supply t These oscilloscope traces are the sensor output when rotating the rotor forth and back. (a bit less than 180º on the 3rd motor) The channel 0 (Yellow) is the Hall 1 and the Channel 1 (Green) is the Hall 2 - + + We can see that in the first movement (positive rotation), the green is out of phase of π/2.` - - ### 3. Encoding the position 1. Get the absolute angle within a period @@ -104,7 +101,6 @@ To achive position control it is necessary to have first, a velocity controller ![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. - - +