# Periodic Jerk in velocity control mode
**URL:** https://community.simplefoc.com/t/periodic-jerk-in-velocity-control-mode/7641
**Category:** applications
**Tags:** esp32, as5600, simplefocmini
**Created:** [September 12, 2025, 11:15pm UTC](https://community.simplefoc.com/t/periodic-jerk-in-velocity-control-mode/7641 "2025-09-12T23:15:46Z")
**Posts on this page:** 7
**Page:** 1
### Author:  [@mig](https://community.simplefoc.com/u/mig)
#### Post date: [September 12, 2025, 11:15pm UTC](https://community.simplefoc.com/t/periodic-jerk-in-velocity-control-mode/7641/1 "2025-09-12T23:15:46Z")
Hi,
New here and have tried to search for this issue without luck, perhaps I didn’t have the correct terminology?
I am running Simple FOC Mini, AS5600 and ESP32-C6 Super Mini.
Overall I can get things working, including angle control. However, when I run velocity control to tune the PID parameters there is a periodic jerk in the motion when the speeds are over approx. 50 r/s.
The period of this disruption is around 2 sec, regardless of the speed.
[https://youtu.be/O66ddPv0T7E](https://youtu.be/O66ddPv0T7E)
Any pointers on where I should start to look for a solution?
Thanks,
Mig
---
### Author:  [@mig](https://community.simplefoc.com/u/mig)
#### Post date: [September 13, 2025, 4:09am UTC](https://community.simplefoc.com/t/periodic-jerk-in-velocity-control-mode/7641/2 "2025-09-13T04:09:29Z")
Seems I found the problem:
[https://www.reddit.com/r/arduino/comments/1iuwcdq/psa\_arduino\_with\_single\_core\_esp32s\_adds\_5ms/](https://www.reddit.com/r/arduino/comments/1iuwcdq/psa_arduino_with_single_core_esp32s_adds_5ms/)
Issue with single core ESP32 and Arduino.
Will try running in a separate task.
---
### Author:  [@loudboy](https://community.simplefoc.com/u/loudboy)
#### Post date: [October 31, 2025, 3:07am UTC](https://community.simplefoc.com/t/periodic-jerk-in-velocity-control-mode/7641/3 "2025-10-31T03:07:43Z")
Did the RTOS solution work for you? I’m experiencing the same 2-second thunk.
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### Author:  [@mig](https://community.simplefoc.com/u/mig)
#### Post date: [October 31, 2025, 3:38am UTC](https://community.simplefoc.com/t/periodic-jerk-in-velocity-control-mode/7641/4 "2025-10-31T03:38:50Z")
Hi,
Yes it solved the problem!
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### Author:  [@loudboy](https://community.simplefoc.com/u/loudboy)
#### Post date: [October 31, 2025, 7:03am UTC](https://community.simplefoc.com/t/periodic-jerk-in-velocity-control-mode/7641/5 "2025-10-31T07:03:44Z")
Wonderful! I’ll give it a shot. Thanks for the feedback.
---
### Author:  [@loudboy](https://community.simplefoc.com/u/loudboy)
#### Post date: [October 31, 2025, 3:12pm UTC](https://community.simplefoc.com/t/periodic-jerk-in-velocity-control-mode/7641/6 "2025-10-31T15:12:16Z")
I think I’ve been sitting here troubleshooting this thing so long that my brain has gone fuzzy and my vision cross-eyed. Would you mind posting your code showing how you implemented the solution?
---
### Author:  [@mig](https://community.simplefoc.com/u/mig)
#### Post date: [November 10, 2025, 10:48am UTC](https://community.simplefoc.com/t/periodic-jerk-in-velocity-control-mode/7641/7 "2025-11-10T10:48:30Z")
Hi, Sorry for delayed response.
Below is the Arduino code that I used just to test if this fixed the problem.
For my actual code I moved all the initialisation out of the task.
[code]
#include \
#define I2C\_SDA 6 // Custom SDA pin
#define I2C\_SCL 7 // Custom SCL pin
TaskHandle\_t TaskHandle\_Motor; //For Motor Control
// BLDC motor & driver instance
BLDCMotor motor = BLDCMotor(7);
BLDCDriver3PWM driver = BLDCDriver3PWM(0, 1, 2, 3);
// encoder instance
//Encoder encoder = Encoder(2, 3, 500);
// Interrupt routine intialisation
// channel A and B callbacks
//void doA(){encoder.handleA();}
//void doB(){encoder.handleB();}
MagneticSensorI2C sensor = MagneticSensorI2C(AS5600\_I2C);
// instantiate the commander
Commander command = Commander(Serial);
void doMotor(char\* cmd) { command.motor(&motor, cmd); }
void setup()
{
// use monitoring with serial
Serial.begin(115200);
xTaskCreate(MyTaskMotor, “TaskMotor”, 2000, NULL, 1, &TaskHandle\_Motor);
}
void loop()
{
vTaskDelete(NULL);
}
/\*--------------------------------------------------\*/
/\*---------------------- Tasks ---------------------\*/
/\*--------------------------------------------------\*/
static void MyTaskMotor(void\* pvParameters)
{
unsigned long timer;
// enable more verbose output for debugging
// comment out if not needed
SimpleFOCDebug::enable(&Serial);
// if SimpleFOCMini is stacked in arduino headers
// on pins 12,11,10,9,8
// pin 12 is used as ground
//pinMode(12,OUTPUT);
//pinMode(12,LOW);
Wire.begin(I2C\_SDA, I2C\_SCL);
// initialise magnetic sensor hardware
sensor.init(&Wire);
// link the motor to the sensor
motor.linkSensor(&sensor);
// driver config
// 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 = 3;
// 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 = 0.17f; [//0.17](https://0.17)
motor.PID\_velocity.I = 0.55; [//0.55](https://0.55)
motor.PID\_velocity.D = 0.0005; [//0.0005](https://0.0005)
// default voltage\_power\_supply
motor.voltage\_limit = 10;
// 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
// default 5ms - try different values to see what is the best.
// the lower the less filtered
motor.LPF\_velocity.Tf = 0.005f; [//0.02](https://0.02)
// angle P controller
motor.P\_angle.P = 6;
motor.P\_angle.D= 0.2; //.2
motor.P\_angle.I= 0.001;
// maximal velocity of the position control
motor.velocity\_limit = 50;
// comment out if not needed
motor.useMonitoring(Serial);
// initialize motor
motor.init();
// align encoder and start FOC
motor.initFOC();
// add target command M
command.add(‘M’, doMotor, “motor”);
Serial.println(F(“Motor ready.”));
Serial.println(F(“Set the target angle using serial terminal:”));
\_delay(1000);
timer = micros();
while(1)
```
{ //Control Loop
if ((micros()-timer) >= 0)
{ timer = micros();
// 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();
// function intended to be used with serial plotter to monitor motor variables
// significantly slowing the execution down!!!!
// motor.monitor();
// user communication
command.run();
}
}
```
}
[/code]
Good luck