BLDC Motor Not Reaching Rated Speed?

Hi, I am using the ROB-20441 BLDC motor, TMC6300 driver, and ESP32-WROOM-32UE. There should be no compatability issues, and the motor is rated at 2000 rpm at 7.4 V. However when I run the basic example code my velocity peaks at about 50 radians per second. Anything higher and the motor freezes. Am I missing something here?

#include <Arduino.h>

    // Open loop motor control example
#include <SimpleFOC.h>

    // BLDC motor & driver instance
    // BLDCMotor motor = BLDCMotor(pole pair number);
    BLDCMotor motor = BLDCMotor(7); // Motor actually has 8 poles, documentation suggests running with 7 poles
    BLDCDriver6PWM driver = BLDCDriver6PWM(33, 32, 26, 25, 14, 27); // uh, ul, vh, vl, wh, wl  ((16,17,18,23,19,33 example code))

    //target variable
    float target_velocity = 100;

    // // instantiate the commander
    Commander command = Commander(Serial);
    // void doTarget(char* cmd) { command.scalar(&target_velocity, cmd); }
    // void doLimit(char* cmd) { command.scalar(&motor.voltage_limit, cmd); }

    void setup() {

      // driver config
      // power supply voltage [V]
      driver.voltage_power_supply = 9;
      // limit the maximal dc voltage the driver can set
      // as a protection measure for the low-resistance motors
      // this value is fixed on startup
      driver.voltage_limit = 9;
      // pwm frequency to be used [Hz]
      // for atmega328 fixed to 32kHz
      // esp32/stm32/teensy configurable
      driver.pwm_frequency = 20000; 

      // link the motor and the driver

      // limiting motor movements
      // limit the voltage to be set to the motor
      // start very low for high resistance motors
      // current = voltage / resistance, so try to be well under 1Amp
      motor.voltage_limit = 7.4;   // [V]

      // open loop control config
      motor.controller = MotionControlType::velocity_openloop;

      // init motor hardware

      // add target command T
      // command.add('T', doTarget, "target velocity");
      // command.add('L', doLimit, "voltage limit");

      Serial.println("Motor ready!");
      Serial.println("Set target velocity [rad/s]");


    void loop() {

      // open loop velocity movement
      // using motor.voltage_limit and motor.velocity_limit

      // user communication;


I think that the problem is that you are using open loop control, so de driver and the mcu have no feedback about the motor, they don’t care if the motor is moving or not. Probably you are trying to accelerate the motor too fast and it can’t go from 0 to 50 rad/s (or higher) instantaneously and it starts “loosing steps”.
Try implementing some acceleration for it. (You also can do it manually increasing the speed gradually in the terminal)

Wow, you were completely correct. I put a simple loop in to increment velocity +1 until it reaches 200 and it works just fine now. Thanks!

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