Hi,
I have slightly modified the example code for ESP32 + I2C magnetic sensor to allow motor commands as suggested by @Antun_Skuric.
here is the code (just for tracability, nothing special)
/**
ESP32 position motion control example with magnetic sensor
*/
#include <SimpleFOC.h>
// SPI Magnetic sensor instance (AS5047U example)
// MISO 12
// MOSI 9
// SCK 14
//MagneticSensorSPI sensor = MagneticSensorSPI(10, 14, 0x3FFF);
// I2C Magnetic sensor instance (AS5600 example)
// make sure to use the pull-ups!!
// SDA 21
// SCL 22
//MagneticSensorI2C(chip_address,bit_resolution, angle_register_msb, bits_used_msb)
MagneticSensorI2C sensor = MagneticSensorI2C(0x36, 12, 0x0E, 4);
// Analog output Magnetic sensor instance (AS5600)
// MagneticSensorAnalog sensor = MagneticSensorAnalog(A1, 14, 1020);
// Motor instance
// BLDCMotor( pin_pwmA, pin_pwmB, pin_pwmC, pole_pairs, enable (optional))
BLDCMotor motor = BLDCMotor(25, 26, 27, 14);
void setup() {
// initialise magnetic sensor hardware
sensor.init();
// link the motor to the sensor
motor.linkSensor(&sensor);
// power supply voltage
// default 12V
motor.voltage_power_supply = 12;
// choose FOC modulation (optional)
motor.foc_modulation = FOCModulationType::SpaceVectorPWM;
// set motion control loop to be used
motor.controller = ControlType::angle;
// contoller configuration
// default parameters in defaults.h
// velocity PI controller parameters
motor.PID_velocity.P = 0.5;
motor.PID_velocity.I = 20;
// maximal voltage to be set to the motor
motor.voltage_limit = 6;
// velocity low pass filtering time constant
// the lower the less filtered
motor.LPF_velocity.Tf = 0.01;
// angle P controller
motor.P_angle.P = 1;
// maximal velocity of the position control
motor.velocity_limit = 30;
// use monitoring with serial
Serial.begin(115200);
// comment out if not needed
motor.useMonitoring(Serial);
// initialize motor
motor.init();
// align sensor and start FOC
motor.initFOC();
Serial.println("Motor ready.");
Serial.println("Set the target angle using serial terminal:");
_delay(1000);
}
// angle set point variable
float target_angle = 0;
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);
motor.move();
// function intended to be used with serial plotter to monitor motor variables
// significantly slowing the execution down!!!!
// motor.monitor();
// // user communication
//serialReceiveUserCommand();
// user communication
motor.command(serialReceiveUserCommand());
}
// utility function enabling serial communication with the user to set the target values
// this function can be implemented in serialEvent function as well
//void serialReceiveUserCommand() {
//
// // a string to hold incoming data
// static String received_chars;
//
// while (Serial.available()) {
// // get the new byte:
// char inChar = (char)Serial.read();
// // add it to the string buffer:
// received_chars += inChar;
// // end of user input
// if (inChar == '\n') {
//
// // change the motor target
// target_angle = received_chars.toFloat();
// Serial.print("Target angle: ");
// Serial.println(target_angle);
//
// // reset the command buffer
// received_chars = "";
// }
// }
//}
// utility function enabling serial communication the user
String serialReceiveUserCommand() {
// a string to hold incoming data
static String received_chars;
String command = "";
while (Serial.available()) {
// get the new byte:
char inChar = (char)Serial.read();
// add it to the string buffer:
received_chars += inChar;
// end of user input
if (inChar == '\n') {
// execute the user command
command = received_chars;
// reset the command buffer
received_chars = "";
}
}
return command;
}
I have noticed a strange behavior (or side effect ?) (or still a bug on my side ?) that I would like to share with you.
When the target position is set to 0, then I can feel a dead zone (very small) where the motor seems to be unpowered. I can’t feel force feedback and even hear a small “clac” as if it was a mechanical backlash.
If I set target at 0.1 (or any other value) then this “backlash” disappears and the force feedback is immediatly present.
Any idea please ? Is it something that you already noticed or am I alone with this “dead spot” ?
Thanks in advance
JP
