Need help with stepper motor

E

exelsion112

New member
Hi everyone! I am new to using a teensy 4.1, I am familiar to the arduino and esp32. I am building a 6dof robotic arm and using normal stepper motors and limit switches.

I am using sn74hct245n level shifter for the signals and it is working fine. But I am having trouble to get the robot to home. When the motor hits the limit switch it does not stop but rather slow down and just go through the limit switch and then go go to normal speed.
I wired the limit as NC, I took the COM pin and wired it to the GND of the teensy and the NC pin I wired it to the teensy pin to track the state. When I tested the limit switch by hand, it worked fine. I am following the pinout provided on the left of the photo for the level shifter. And for the signals I wired the +5v pins all to the power supply +5v and took the -signal pins to the teensy.

I am using plateformIO and arduino framework for the teensy, and using fastAccelStepper Library to control the stepper.
 

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It might help if we could see your code.
When you paste it (the code) use the </> button, which ensures that code formatting is maintained.
 
BriComp said:
It might help if we could see your code.
When you paste it (the code) use the </> button, which ensures that code formatting is maintained.
Click to expand...
I tried a test to see the live state when the motor is moving, I noticed that the state is clear when the switch is engaged but when it is engaged the state is changing very fast between 1 and 0. So the signal is not clear, I think this is what is causing the slow movement when the stepper touches the limit switch. Here is the code:

Code: 
#include <Arduino.h>

#include <AccelStepper.h>

#include <string.h>



/*

  The step resolution for all drivers : 6400 step/revolution

  J1 10:1

  J2 25:1

  J3 25:1

  J4 15:1

  J5 9:1

  J6 6:1



  J2-J3: 230mm

  J4-J6: 230mm

  Total reach : 460mm



  homing:

  J1: 40deg from limit

  J2: 25deg from limit

  J3: 130deg from limit

  J4: 150deg from limit

  J5: around 90deg from limit

  J6: home position at limit

*/





//States Definitions

// #define ESTOP 4

// #define KEYED_SWITCH_L 2

// #define KEYED_SWITCH_R 15



//Steppers Definitions

#define MOTOR_DRIVER 1

#define MAX_ACCELERATION 750

#define MAX_SPEED 3000



//Limit Switches Definitions

#define L1 23

#define L2 22

#define L3 19

#define L4 18

#define L5 15

#define L6 14



AccelStepper J1(MOTOR_DRIVER, 0, 1);

AccelStepper J2(MOTOR_DRIVER, 2, 3);

AccelStepper J3(MOTOR_DRIVER, 4, 5);



AccelStepper J4(MOTOR_DRIVER, 6, 7);

AccelStepper J5(MOTOR_DRIVER, 8, 9);

AccelStepper J6(MOTOR_DRIVER, 10, 11);



long stepsToAngle(double angle, double gearRatio){

  const int microstep = 32;

  const int stepsPerRev = 200;



  double stepsPerDegree = (stepsPerRev * microstep * gearRatio) / 360.0;



  return (long)(angle * stepsPerDegree);

}





void homeAllJoints() {

  Serial.println("START HOME SEQUENCE");



  // Arrays for 5 joints only

  AccelStepper* mainJoints[] = {&J2, &J3, &J1};

  int mainLimitPins[] = {L2, L3, L1};

  double mainRatios[] = {25.0, 25.0, 10.0};

  double mainHomePos[] = {25.0, 130.0, 40.0};



  for (int i = 0; i < 3; i++){

    mainJoints[i]->setSpeed(-2000);

    while(digitalRead(mainLimitPins[i]) == LOW){

      mainJoints[i]->runSpeed();

    }



    mainJoints[i]->stop();

    delay(200);

    mainJoints[i]->setCurrentPosition(0);



    long clearance = stepsToAngle(5.0, mainRatios[i]);

    mainJoints[i]->moveTo(clearance);

    while(mainJoints[i]->distanceToGo() != 0)

      mainJoints[i] ->run();



    mainJoints[i]->setSpeed(-500);

    while (digitalRead(mainLimitPins[i]) == LOW) {

      mainJoints[i]->runSpeed();

    }

   

    // 4. SET ZERO: This is now the official 0 point

    mainJoints[i]->stop();

    mainJoints[i]->setCurrentPosition(0);

    delay(100);



    // 5. MOVE TO HOME POSITION: Move to your desired "Starting Pose"

    long homeSteps = stepsToAngle(mainHomePos[i], mainRatios[i]);

    mainJoints[i]->moveTo(homeSteps);

   

    // IMPORTANT: Wait for move to finish before starting next joint

    while (mainJoints[i]->distanceToGo() != 0) {

      mainJoints[i]->run();

    }

  }



  AccelStepper *wristJoints[] = {&J5, &J4};

  int wristLimitPins[] = {L5, L4};

  double wristRatios[] = {9.0, 15.0};

  double wristHomePos[] = {90.0, 150.0};



  for (int i = 0; i < 2; i++){

    wristJoints[i]->setSpeed(-2000);

    while(digitalRead(wristLimitPins[i]) == LOW){

      wristJoints[i]->runSpeed();

    }



    wristJoints[i]->stop();

    delay(200);

    wristJoints[i]->setCurrentPosition(0);



    long clearance = stepsToAngle(5.0, wristRatios[i]);

    wristJoints[i]->moveTo(clearance);

    while(wristJoints[i]->distanceToGo() != 0)

      wristJoints[i] ->run();



    wristJoints[i]->setSpeed(-500);

    while (digitalRead(wristLimitPins[i]) == LOW) {

      wristJoints[i]->runSpeed();

    }

   

    // 4. SET ZERO: This is now the official 0 point

    wristJoints[i]->stop();

    wristJoints[i]->setCurrentPosition(0);

    delay(100);



    // 5. MOVE TO HOME POSITION: Move to your desired "Starting Pose"

    long homeSteps = stepsToAngle(wristHomePos[i], wristRatios[i]);

    wristJoints[i]->moveTo(homeSteps);

   

    // IMPORTANT: Wait for move to finish before starting next joint

    while (wristJoints[i]->distanceToGo() != 0) {

      wristJoints[i]->run();

    }

  }

  J6.setCurrentPosition(0);



  Serial.println("HOME SEQUENCE COMPLETE");

}





void setup() {

  // put your setup code here, to run once:

  Serial.begin(115200);



  // Stepper Motors Setup


  // Turned the signals into sinking 

  J1.setAcceleration(MAX_ACCELERATION);

  J1.setMaxSpeed(MAX_SPEED);

  J1.setPinsInverted(true, false, false);



  J2.setAcceleration(MAX_ACCELERATION);

  J2.setMaxSpeed(MAX_SPEED);

  J2.setPinsInverted(true, false, false);



  J3.setAcceleration(MAX_ACCELERATION);

  J3.setMaxSpeed(MAX_SPEED);

  J3.setPinsInverted(true, false, false);



  J4.setAcceleration(MAX_ACCELERATION);

  J4.setMaxSpeed(MAX_SPEED);

  J4.setPinsInverted(true, false, false);


  J5.setAcceleration(MAX_ACCELERATION);

  J5.setMaxSpeed(MAX_SPEED);

  J5.setPinsInverted(true, false, false);



  J6.setAcceleration(MAX_ACCELERATION);

  J6.setMaxSpeed(MAX_SPEED);

  J6.setPinsInverted(true, false, false);



  //Limit Switches Setup

  pinMode(L1, INPUT_PULLUP);

  pinMode(L2, INPUT_PULLUP);

  pinMode(L3, INPUT_PULLUP);

  pinMode(L4, INPUT_PULLUP);

  pinMode(L5, INPUT_PULLUP);

  pinMode(L6, INPUT_PULLUP);


}



void loop() {

  // put your main code here, to run repeatedly:

  J1.setSpeed(500);

  while(digitalRead(L1) == LOW){

    J1.runSpeed();

    Serial.println(digitalRead(L1));

  }

}
 
I compressed your code a bit, you seem to be double spacing lines.
Code: 
#include <Arduino.h>
#include <AccelStepper.h>
#include <string.h>

/*
  The step resolution for all drivers : 6400 step/revolution

  J1 10:1
  J2 25:1
  J3 25:1
  J4 15:1
  J5 9:1
  J6 6:1

  J2-J3: 230mm
  J4-J6: 230mm

  Total reach : 460mm

  homing:

  J1: 40deg from limit
  J2: 25deg from limit
  J3: 130deg from limit
  J4: 150deg from limit
  J5: around 90deg from limit
  J6: home position at limit

*/

//States Definitions

// #define ESTOP 4
// #define KEYED_SWITCH_L 2
// #define KEYED_SWITCH_R 15

//Steppers Definitions

#define MOTOR_DRIVER 1
#define MAX_ACCELERATION 750
#define MAX_SPEED 3000

//Limit Switches Definitions

#define L1 23
#define L2 22
#define L3 19
#define L4 18
#define L5 15
#define L6 14

AccelStepper J1(MOTOR_DRIVER, 0, 1);
AccelStepper J2(MOTOR_DRIVER, 2, 3);
AccelStepper J3(MOTOR_DRIVER, 4, 5);

AccelStepper J4(MOTOR_DRIVER, 6, 7);
AccelStepper J5(MOTOR_DRIVER, 8, 9);
AccelStepper J6(MOTOR_DRIVER, 10, 11);

long stepsToAngle(double angle, double gearRatio) {

    const int microstep = 32;
    const int stepsPerRev = 200;
    double stepsPerDegree = (stepsPerRev * microstep * gearRatio) / 360.0;
    return (long)(angle * stepsPerDegree);
}

void homeAllJoints() {

    Serial.println("START HOME SEQUENCE");

    // Arrays for 5 joints only

    AccelStepper* mainJoints[] = { &J2, &J3, &J1 };
    int mainLimitPins[] = { L2, L3, L1 };
    double mainRatios[] = { 25.0, 25.0, 10.0 };
    double mainHomePos[] = { 25.0, 130.0, 40.0 };

    for (int i = 0; i < 3; i++) {
        mainJoints[i]->setSpeed(-2000);
        while (digitalRead(mainLimitPins[i]) == LOW) {
            mainJoints[i]->runSpeed();
        }
        mainJoints[i]->stop();
        delay(200);
        mainJoints[i]->setCurrentPosition(0);
        long clearance = stepsToAngle(5.0, mainRatios[i]);
        mainJoints[i]->moveTo(clearance);

        while (mainJoints[i]->distanceToGo() != 0)
            mainJoints[i]->run();

        mainJoints[i]->setSpeed(-500);

        while (digitalRead(mainLimitPins[i]) == LOW) {
            mainJoints[i]->runSpeed();
        }

        // 4. SET ZERO: This is now the official 0 point

        mainJoints[i]->stop();
        mainJoints[i]->setCurrentPosition(0);
        delay(100);

        // 5. MOVE TO HOME POSITION: Move to your desired "Starting Pose"

        long homeSteps = stepsToAngle(mainHomePos[i], mainRatios[i]);
        mainJoints[i]->moveTo(homeSteps);

        // IMPORTANT: Wait for move to finish before starting next joint

        while (mainJoints[i]->distanceToGo() != 0) {
            mainJoints[i]->run();
        }
    }

    AccelStepper* wristJoints[] = { &J5, &J4 };
    int wristLimitPins[] = { L5, L4 };
    double wristRatios[] = { 9.0, 15.0 };
    double wristHomePos[] = { 90.0, 150.0 };

    for (int i = 0; i < 2; i++) {
        wristJoints[i]->setSpeed(-2000);
        while (digitalRead(wristLimitPins[i]) == LOW) {
            wristJoints[i]->runSpeed();
        }
        wristJoints[i]->stop();
        delay(200);
        wristJoints[i]->setCurrentPosition(0);

        long clearance = stepsToAngle(5.0, wristRatios[i]);

        wristJoints[i]->moveTo(clearance);
        while (wristJoints[i]->distanceToGo() != 0)
            wristJoints[i]->run();

        wristJoints[i]->setSpeed(-500);
        while (digitalRead(wristLimitPins[i]) == LOW) {
            wristJoints[i]->runSpeed();
        }

        // 4. SET ZERO: This is now the official 0 point

        wristJoints[i]->stop();
        wristJoints[i]->setCurrentPosition(0);
        delay(100);

        // 5. MOVE TO HOME POSITION: Move to your desired "Starting Pose"

        long homeSteps = stepsToAngle(wristHomePos[i], wristRatios[i]);

        wristJoints[i]->moveTo(homeSteps);

        // IMPORTANT: Wait for move to finish before starting next joint

        while (wristJoints[i]->distanceToGo() != 0) {
            wristJoints[i]->run();
        }
    }

    J6.setCurrentPosition(0);
    Serial.println("HOME SEQUENCE COMPLETE");
}

void setup() {

    // put your setup code here, to run once:

    Serial.begin(115200);

    // Stepper Motors Setup
    // Turned the signals into sinking

    J1.setAcceleration(MAX_ACCELERATION);
    J1.setMaxSpeed(MAX_SPEED);
    J1.setPinsInverted(true, false, false);

    J2.setAcceleration(MAX_ACCELERATION);
    J2.setMaxSpeed(MAX_SPEED);
    J2.setPinsInverted(true, false, false);

    J3.setAcceleration(MAX_ACCELERATION);
    J3.setMaxSpeed(MAX_SPEED);
    J3.setPinsInverted(true, false, false);

    J4.setAcceleration(MAX_ACCELERATION);
    J4.setMaxSpeed(MAX_SPEED);
    J4.setPinsInverted(true, false, false);

    J5.setAcceleration(MAX_ACCELERATION);
    J5.setMaxSpeed(MAX_SPEED);
    J5.setPinsInverted(true, false, false);

    J6.setAcceleration(MAX_ACCELERATION);
    J6.setMaxSpeed(MAX_SPEED);
    J6.setPinsInverted(true, false, false);

    //Limit Switches Setup

    pinMode(L1, INPUT_PULLUP);
    pinMode(L2, INPUT_PULLUP);
    pinMode(L3, INPUT_PULLUP);
    pinMode(L4, INPUT_PULLUP);
    pinMode(L5, INPUT_PULLUP);
    pinMode(L6, INPUT_PULLUP);
}

void loop() {

    // put your main code here, to run repeatedly:

    J1.setSpeed(500);

    while (digitalRead(L1) == LOW) {
        J1.runSpeed();
        Serial.println(digitalRead(L1));
    }
}
 
Internal pullups are very weak - try external 1k pullup resistors on the limit switches so they are more immune to noise from the motors and motor supply wiring?
 
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