I am trying to run a motor in Closed-loop velocity control this is my setup
ESP32
DRV8302 driver board
Maxon EC I 30 motor using Hall sensors as feedback
I have had the motor run in Open-loop and Closed-loop control voltage with no problem
My problem is after the motor has run through its initial alignment and calibration routine (without any problems) the motor just goes mad for a second then stops.
The Volt_Q returns nan and Vel return inf in the monitor.
I have try turning the P term down very low wit the I and D terms set to 0 but this has no affect
What am I doing wrong?
here is my code
#include <SimpleFOC.h>
//define Pinout DRV8302
#define INH_A 25 //PWM_A
#define INH_B 26 //PWM_B
#define INH_C 27 //PWM_C
#define EN_GATE 16
#define M_PWM 17
#define M_OC 18
#define OC_ADJ 19
// Postion Sensor Hall's
#define HallA 21
#define HallB 22
#define HallC 23
#define PP 4 //Pole Pairs
// BLDC motor & driver instance
// BLDCMotor motor = BLDCMotor(pole pair number, phase resistance (optional) );
BLDCMotor motor = BLDCMotor(PP);
// BLDC driver instance
BLDCDriver3PWM driver = BLDCDriver3PWM(INH_A, INH_B, INH_C, EN_GATE);
// Hall sensor instance
HallSensor sensor = HallSensor(HallA, HallB, HallC, PP);
// Interrupt routine intialisation
// channel A and B callbacks
void doA(){sensor.handleA();}
void doB(){sensor.handleB();}
void doC(){sensor.handleC();}
// velocity set point variable
float target_velocity = 0;
// instantiate the commander
Commander command = Commander(Serial);
void doTarget(char* cmd) { command.scalar(&target_velocity, cmd); }
/////////////////////////////////////////////////////////////////////////////////////////////////
void setup() {
// DRV8302 specific code
// M_OC - enable overcurrent protection
pinMode(M_OC,OUTPUT);
digitalWrite(M_OC,LOW);
// M_PWM - enable 3pwm mode
pinMode(M_PWM,OUTPUT);
digitalWrite(M_PWM,HIGH);
// OC_ADJ - set the maximum overcurrent limit possible
// Better option would be to use voltage divisor to set exact value
pinMode(OC_ADJ,OUTPUT);
digitalWrite(OC_ADJ,HIGH);
// initialize sensor hardware
sensor.pullup = Pullup::USE_EXTERN;
sensor.init();
sensor.enableInterrupts(doA, doB, doC);
// link the motor to the sensor
motor.linkSensor(&sensor);
// pwm frequency to be used [Hz]
// esp32 configurable
driver.pwm_frequency = 50000;
// power supply voltage [V]
driver.voltage_power_supply = 12;
driver.init();
// link the motor and the driver
motor.linkDriver(&driver);
// aligning voltage [V]
motor.voltage_sensor_align = 1;
// index search velocity [rad/s]
motor.velocity_index_search = 1;
// set motion control loop to be used
motor.torque_controller = TorqueControlType::voltage;
motor.controller = MotionControlType::velocity;
// contoller configuration
// default parameters in defaults.h
// velocity PI controller parameters
motor.PID_velocity.P = 1.0f;
motor.PID_velocity.I = 0;
motor.PID_velocity.D = 0;
// default voltage_power_supply
motor.voltage_limit = 6;
// jerk control using voltage voltage ramp
// default value is 300 volts per sec ~ 0.3V per millisecond
motor.PID_velocity.output_ramp = 1000;
// velocity low pass filtering time constant
motor.LPF_velocity.Tf = 0.01f;
// Setup for monitor
Serial.begin(115200); // the higher the better
motor.useMonitoring(Serial);
//display variables
motor.monitor_variables = _MON_TARGET | _MON_VOLT_Q | _MON_VEL; // set monitoring of d and q currents
// downsampling
motor.monitor_downsample = 100; // default 10
// initialize motor
motor.init();
// align sensor and start FOC
motor.initFOC();
// add target command T
command.add('T', doTarget, "target velocity");
Serial.println(F("Motor ready."));
Serial.println(F("Set the target velocity 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_velocity);
// function intended to be used with serial plotter to monitor motor variables
// significantly slowing the execution down!!!!
motor.monitor();
// user communication
command.run();
}
Start with PID values of Zero and using the commander interface start changing their values. I also had a similar issue and found out that the Hall sensor required a pull-up resistor after adding the pull-up resistor, I was able to tune the PID parameter.
Yes, It will, but you can turn the motor on again by changing the P value first. when you see that the motor is moving fine with P-value, start changing the I value and then at the end D value.
That’s my problem, even if I have a really low value (say 0.01) for the P term and I and D set to 0. the motor just goes mad totally random action. The loop seems to crash returning the voltage value as ‘Not a Number’ and the velocity as infinite.
If I change this code MotionControltypr to torque it operates the same way if the target is position it rotates clockwise if the target is negative counterclockwise.
Do you see the messages during motor initialisation? Could you post a copy of these? If you’re not seeing them a while (!Serial) ; after Serial.begin(115200); can help.
// set motion control loop to be used
motor.torque_controller = TorqueControlType::voltage;
motor.controller = MotionControlType::velocity;
// contoller configuration
// default parameters in defaults.h
// velocity PI controller parameters
motor.PID_velocity.P = 0.1f;
motor.PID_velocity.I = 0;
motor.PID_velocity.D = 0;
// default voltage_power_supply
motor.voltage_limit = 6;
// jerk control using voltage voltage ramp
// default value is 300 volts per sec ~ 0.3V per millisecond
motor.PID_velocity.output_ramp = 300;
// velocity low pass filtering time constant
motor.LPF_velocity.Tf = 0.01f;
Did you try the sensor alone?
Using one of the hall sensor stand alone examples?
Can you plot the velocity and the angle value and see if you have the same behavior?
Yes, I have been through all the stages testing the sensor and the driver, also running it in an open loop.
I did initially have a problem with the hall sensor signal (see my other post) but I think this is fixed and I am getting good position data.
Here is a plot of my setup running in torque mode, with the target set to 0.25 (it’s
Small update, I tried going back to an Arduino Mega to see if the problem was with the ESP32. The result was it didn’t even get through the initialisation process the motor just locked in one position during the alignment process
This is very strange. if the motor locks during the init that most probably has nothing to do with the sensor.
Your velocity measurement is very noisy, but it seems ok in the second plot. It is possible that we have an issue witht the HallSensor class somewhere. We did not tuch it for some time now.
However, it was developed on esp32 by @Owen_Williams so it definitely should work both for arduinos and esp32s.
I’ll try to test it tonight and I’ll let you know if I can reproduce it.
I understand. How does it look like when you use velocity control. The motor starts spinning in one direction and then it stops.
Was that the behavior when you took this screenshot?
Did your motor start and stop like it seems like from the velocity profile?
Did you try to use the very very low values of velocity P gain, under 0.01?
You can fix I and D to zero for now.
you can also try using the ramp value, try settting the PID_velocity.ramp=1000
You can also maybe test with a lower value under 200.
You can also try downsampling the motion control loop by using the motor.motion_downsample parameter. Try setting the downsampling between 10 and 100 .
Lots of questions there I’ll try and answer them without disappearing into a rabbit hole.
Yes, this plot is when I try to run the motor in closed-loop velocity mode using hall sensors as feedback. The motor does turn very erratically (as you can see from the velocity profile) until the loop seems to crash. Voltage returns ‘nan’ and velocity returns ‘inf’
I have turned the P term as low as 0.02 with I and D terms set to 0. I can get the motor to run if the target is above 10 rad/s although the motion is very lumpy. If I set the target below this or turn the P term any lower the motor will not run. If I go higher with the P term I just get the erratic behavior.
I have tried changing the motor.PID_velocity.output_ramp to both high and low values (10 to 1000) but this does seem to have any effect.
For the monitoring, I am using motor.monitor_downsample does motor.motion_downsample offer any different functionality?
