Problems getting roboter arm joint into closed loop angle control

hardware support
1

Hi, so for quite some time now I have been trying to get my roboter axis into closed loop control using the simple foc library, but I have stumbled into quite some issues :melting_face:

Here you can see my gimbal bldc motor (GM7008H) in open loop control:

Note that when I enter the target velocity when I run the code the motor starts oscilating and not moving at the desired speed. I have to also put the current limit down using the command prompt, which I find is pretty weird :upside_down_face:

The AS5047p magnetic encoder, which I read out via SPI works great and I already tested it seperately using the code from the github examples.

So here is the code I use for the angle control loop:

#include <SimpleFOC.h>

// magnetic sensor instance - SPI
MagneticSensorSPI sensor = MagneticSensorSPI(34, 14, 0x3FFF);
// magnetic sensor instance - MagneticSensorI2C
//MagneticSensorI2C sensor = MagneticSensorI2C(AS5600_I2C);
// magnetic sensor instance - analog output
// MagneticSensorAnalog sensor = MagneticSensorAnalog(A1, 14, 1020);

// BLDC motor & driver instance
BLDCMotor motor = BLDCMotor(11, 10.8, 28);
BLDCDriver3PWM driver = BLDCDriver3PWM(1, 2, 3, 4);
// Stepper motor & driver instance
//StepperMotor motor = StepperMotor(50);
//StepperDriver4PWM driver = StepperDriver4PWM(9, 5, 10, 6,  8);

// angle set point variable
float target_angle = 0;
// instantiate the commander
Commander command = Commander(Serial);
void doTarget(char* cmd) { command.scalar(&target_angle, cmd); }

void setup() {

  // initialise magnetic sensor hardware
  sensor.init();
  // link the motor to the sensor
  motor.linkSensor(&sensor);

  // driver config
  // power supply voltage [V]
  driver.voltage_power_supply = 24;
  driver.init();
  // link the motor and the driver
  motor.linkDriver(&driver);

  // choose FOC modulation (optional)
  motor.foc_modulation = FOCModulationType::SpaceVectorPWM;

  // set motion control loop to be used
  motor.controller = MotionControlType::angle;

  // contoller configuration
  // default parameters in defaults.h

  // velocity PI controller parameters
  motor.PID_velocity.P = 0.2f;
  motor.PID_velocity.I = 20;
  motor.PID_velocity.D = 0;
  // maximal voltage to be set to the motor
  motor.voltage_limit = 20;
  motor.current_limit = 1;

  // velocity low pass filtering time constant
  // the lower the less filtered
  motor.LPF_velocity.Tf = 0.01f;

  // angle P controller
  motor.P_angle.P = 20;
  // maximal velocity of the position control
  motor.velocity_limit = 10;

  // use monitoring with serial
  Serial.begin(9600);
  // comment out if not needed
  motor.useMonitoring(Serial);


  // initialize motor
  motor.init();
  // align sensor and start FOC
  motor.initFOC();

  // add target command T
  command.add('T', doTarget, "target angle");

  Serial.println(F("Motor ready."));
  Serial.println(F("Set the target angle using serial terminal:"));
  _delay(1000);
}


void loop() {
  // main FOC algorithm function
  // the faster you run this function the better
  // Arduino UNO loop  ~1kHz
  // Bluepill loop ~10kHz
  motor.loopFOC();

  // Motion control function
  // velocity, position or voltage (defined in motor.controller)
  // this function can be run at much lower frequency than loopFOC() function
  // You can also use motor.move() and set the motor.target in the code
  motor.move(target_angle);


  // function intended to be used with serial plotter to monitor motor variables
  // significantly slowing the execution down!!!!
  // motor.monitor();

  // user communication
  command.run();
}

The bldc motor inits no problem, but then it doesn’t move to the desired position… If I send a target angle it does nothing. But what is interesting if I help with the hand it will move to a position and then hold this position.

Thanks for the help in advance…