pidMotor

Connection to motors in closed-loop PID control on Arduino MKR Motor Carrier or Nano Motor Carrier

Description

This object represents a connection to motors running in closed-loop PID control with the specified motor number on the MKR Motor Carrier or Nano Motor Carrier. You can control the DC motors M1 and M2 in closed-loop PID control using the functions in Object Functions.

Creation

Syntax

pidObj = pidMotor(mcObj,PIDNumber)

pidObj = pidMotor(mcObj,PIDNumber,controlmode)

pidObj = pidMotor(mcObj,PIDNumber,controlmode,ppr)

pidObj = pidMotor(mcObj,PIDNumber,controlmode,ppr,[PIDGains])

Description

pidObj = pidMotor(mcObj,PIDNumber) creates a connection to the PID motor at the specified port number on the Arduino^® MKR Motor Carrier or the Nano Motor Carrier.

pidObj = pidMotor(mcObj,PIDNumber,controlmode) creates a connection to the PID motor at the specified port number and the specified control mode on the Arduino MKR Motor Carrier or the Nano Motor Carrier.

pidObj = pidMotor(mcObj,PIDNumber,controlmode,ppr) creates a connection to the PID motor at the specified port number with the specified pulses per revolution on the Arduino MKR Motor Carrier or the Nano Motor Carrier.

pidObj = pidMotor(mcObj,PIDNumber,controlmode,ppr,[PIDGains]) creates a connection to the PID motor at the specified port number and specified PID gains on the Arduino MKR Motor Carrier or the Nano Motor Carrier.

Input Arguments

mcObj — MKR Motor Carrier or Nano Motor Carrier connection

object

Connection to the MKR Motor Carrier or Nano Motor Carrier, specified as an object.

Example: pidObj = pidMotor(mcObj,1) creates a connection to the motor number 1.

PIDNumber — PID motor number

1 | 2

Motor number where the PID motor is connected on an MKR Motor Carrier or Nano Motor Carrier, specified as a number. The PIDNumber 1 implies a connection to the motor number 1 (M1) and the encoder 1 whereas the PIDNumber 2 implies a connection to the motor number 2 (M2) and the encoder 2.

Example: pidObj = pidMotor(mcObj,2) creates a connection to the motor number 2.

controlmode — Mode of control

'speed' (default) | 'position'

The mode of control of the PID motor, specified as a character vector. To drive the DC motor at the specified speed, create the connection to the PID motor in speed control mode. To rotate the motor by the specified angle, create the connection to the PID motor in position control mode.

Example: pidObj = pidMotor(mcObj,1,'Position'); creates a connection to the motor number 1 in the position control mode.

ppr — Number of pulses per revolution

3 (default)

Number of pulses per revolution of the rotary encoder, specified as a number.

Example: pidObj = pidMotor(mcObj,1,'Position',3); sets the pulses pulse per revolution to 3.

[PIDGains] — Proportional, intergral and derivative gains

1-by-3 vector

Proportional (Kp), integral (Ki), and derivative (Kd) gains of the PID motor specified as a 1-by-3 vector. The following are the default values of [Kp,Ki,Kd] in the speed and position control modes:

Board	speed Control Mode	position Control Mode
Arduino MKR Motor Carrier	[2000,200, 0]	[25,0,3]
Arduino Nano Motor Carrier	[5.2,0.3,0.0]	[0.18, 0.0, 0.01]

Note

Tuning gains can lead to the motor and board getting burnt in case of excess current. Also, the Arduino firmware does not allow setting MaxSpeed to ensure safety.

Example: pidObj = pidMotor(mcObj,1,'Position',3,[25,0,3]); sets the PID gains of the PID motor on the MKR Motor Carrier to 25, 0, and 3.

Data Types: double

Properties

PIDNumber — PID Motor number

1 | 2

This property is read-only.

PID motor number corresponding to DC motor number and encoder channel number on an MKR Motor Carrier or Nano Motor Carrier, specified as a number.

Example:

>> pidObj.PIDNumber
ans = 
      1 

Data Types: double

ControlMode — Mode of control

'speed' (default) | 'position'

This property is read-only.

The mode of control of the PID motor, specified as a string.

Example:

>> pidObj.ControlMode
ans = 
      'speed' 

Data Types: char

PulsesPerRevolution — Number of pulses per revolution

3 (default)

This property is read-only.

Number of pulses per revolution of encoder, specified as a number.

Example:

>> pidObj.PulsesPerRevolution
ans = 
      3 

Data Types: double

Kp — Proportional gain

numeric

Proportional gain of the PID control.

Example:

>> pidObj.Kp
ans = 
       2000

Data Types: double

Ki — Integral gain

numeric

Integral gain of the PID control.

Example:

>> pidObj.Ki
ans = 
       200

Data Types: double

Kd — Derivative gain

numeric

Derivative gain of the PID control.

Example:

>> pidObj.Kd
ans = 
       0

Data Types: double

MaxAcceleration — Maximum acceleration

scalar

This property is read-only.

Maximum acceleration in radians per seconds squared.

Example:

>> pidObj.MaxAcceleration
ans = 
       2094400000 (rad/s2)

Data Types: double

MaxSpeed — Maximum speed

scalar

This property is read-only.

Maximum acceleration in revolutions per minute.

Example:

>> pidObj.MaxSpeed
ans = 
       25000 RPM

Data Types: double

Object Functions

Use these object functions to create a connection to the PID motor:

readAngularPosition	Read angular position of DC Motor in closed-loop control
readSpeed	Read current rotational speed of DC Motor in closed loop control
writeAngularPosition	Rotate DC motor by specified angle in closed loop position control
writeSpeed	Write speed of PID motor

Examples

Create Connection to PID Motor on Nano Motor Carrier

Create an arduino object with the 'MotorCarrier' library.

arduinoObj = arduino('/dev/ttyACM0','Nano33IoT','Libraries','MotorCarrier')

arduinoObj = 
  arduino with properties:

                  Port: '/dev/ttyACM0'
                 Board: 'Nano33IoT'
         AvailablePins: {'D0-D13', 'A0-A7'}
  AvailableDigitalPins: {'D0-D13', 'A0-A7'}
      AvailablePWMPins: {'D2-D6', 'D9-D10'}
   AvailableAnalogPins: {'A0-A3', 'A6-A7'}
    AvailableI2CBusIDs: [0]
AvailableSerialPortIDs: [1]
             Libraries: {'MotorCarrier'}
Show all properties

Create a connection to the Nano Motor Carrier.

mcObj = motorCarrier(arduinoObj)

mcObj = 
  MotorCarrier with properties:

          SCLPin: 'A5'
          SDAPin: 'A4'
      I2CAddress: 102 ('0x66')

Create a connection to the PID motor.

pidObj = pidMotor(mcObj,1)

pidObj = 
  PIDMotor with properties:

             PIDNumber: 1
           ControlMode:'speed'
   PulsesPerRevolution: 3
                    Kp: 5.200000
                    Ki: 0.300000
                    Kd: 0.000000
       MaxAcceleration: 2094400000 (rad/s^2)
              MaxSpeed: 25000 (RPM)

Specify Mode of Control

Create an arduino object with the 'MotorCarrier' library.

arduinoObj = arduino('/dev/ttyACM0','Nano33IoT','Libraries','MotorCarrier')

arduinoObj = 
  arduino with properties:

                  Port: '/dev/ttyACM0'
                 Board: 'Nano33IoT'
         AvailablePins: {'D0-D13', 'A0-A7'}
  AvailableDigitalPins: {'D0-D13', 'A0-A7'}
      AvailablePWMPins: {'D2-D6', 'D9-D10'}
   AvailableAnalogPins: {'A0-A3', 'A6-A7'}
    AvailableI2CBusIDs: [0]
AvailableSerialPortIDs: [1]
             Libraries: {'MotorCarrier'}
Show all properties

Create a connection to the Nano Motor Carrier.

mcObj = motorCarrier(arduinoObj)

mcObj = 
  MotorCarrier with properties:

          SCLPin: 'A5'
          SDAPin: 'A4'
      I2CAddress: 102 ('0x66')

Create a connection to the PID motor in 'Position' control mode.

pidObj = pidMotor(mcObj,1,'position')

pidObj = 
  PIDMotor with properties:

             PIDNumber: 1
           ControlMode:'position'
   PulsesPerRevolution: 3
                    Kp: 0.180000
                    Ki: 0.000000
                    Kd: 0.010000
       MaxAcceleration: 2094400000 (rad/s^2)
              MaxSpeed: 25000 (RPM)

Specify Pulses Per Revolution

Create an arduino object with the 'MotorCarrier' library.

arduinoObj = arduino('/dev/ttyACM0','Nano33IoT','Libraries','MotorCarrier')

arduinoObj = 
  arduino with properties:

                  Port: '/dev/ttyACM0'
                 Board: 'Nano33IoT'
         AvailablePins: {'D0-D13', 'A0-A7'}
  AvailableDigitalPins: {'D0-D13', 'A0-A7'}
      AvailablePWMPins: {'D2-D6', 'D9-D10'}
   AvailableAnalogPins: {'A0-A3', 'A6-A7'}
    AvailableI2CBusIDs: [0]
AvailableSerialPortIDs: [1]
             Libraries: {'MotorCarrier'}
Show all properties

Create a connection to the Nano Motor Carrier.

mcObj = motorCarrier(arduinoObj)

mcObj = 
  MotorCarrier with properties:

          SCLPin: 'A5'
          SDAPin: 'A4'
      I2CAddress: 102 ('0x66')

Create a connection to the PID motor in 'Position' control mode.

pidObj = pidMotor(mcObj,1,'position',3)

pidObj = 
  PIDMotor with properties:

             PIDNumber: 1
           ControlMode:'position'
   PulsesPerRevolution: 3
                    Kp: 0.180000
                    Ki: 0.000000
                    Kd: 0.010000
       MaxAcceleration: 2094400000 (rad/s^2)
              MaxSpeed: 25000 (RPM)

Specify PID Gains

Create an arduino object with the 'MotorCarrier' library.

arduinoObj = arduino('/dev/ttyACM0','Nano33IoT','Libraries','MotorCarrier')

arduinoObj = 
  arduino with properties:

                  Port: '/dev/ttyACM0'
                 Board: 'Nano33IoT'
         AvailablePins: {'D0-D13', 'A0-A7'}
  AvailableDigitalPins: {'D0-D13', 'A0-A7'}
      AvailablePWMPins: {'D2-D6', 'D9-D10'}
   AvailableAnalogPins: {'A0-A3', 'A6-A7'}
    AvailableI2CBusIDs: [0]
AvailableSerialPortIDs: [1]
             Libraries: {'MotorCarrier'}
Show all properties

Create a connection to the Nano Motor Carrier.

mcObj = motorCarrier(arduinoObj)

mcObj = 
  MotorCarrier with properties:

          SCLPin: 'A5'
          SDAPin: 'A4'
      I2CAddress: 102 ('0x66')

Create a connection to the PID motor in 'Position' control mode.

pidObj = pidMotor(mcObj,1,'position',3,[0.18, 0.0, 0.01])

pidObj = 
  PIDMotor with properties:

             PIDNumber: 1
           ControlMode:'position'
   PulsesPerRevolution: 3
                    Kp: 0.180000
                    Ki: 0.000000
                    Kd: 0.010000
       MaxAcceleration: 2094400000 (rad/s^2)
              MaxSpeed: 25000 (RPM)