SmartMotor Class Reference

Class used to control DC motors at a constant speed. More...

#include <SmartMotor.h>

Public Member Functions
	SmartMotor (byte pwm, byte dir, byte enc_a, byte enc_b, bool invert=false, PIO pio=pio0)
	Create SmartMotor object, creating all necessary objects.
void	begin ()
	Initialize SmartMotor and necessary components.
void	update ()
	Update routine, updating the PID and the motor speed.
void	setSpeed (float value)
	Set the desired speed of the motor.
float	getSpeed ()
	Get the current speed of the motor.
void	stop ()
	Stop the motor.
void	calibrate (float target=45.f)
	Calibrate the PID controller.

Detailed Description

Class used to control DC motors at a constant speed.

Relies on a PID controller receiving data from a rotary encoder that uses a PIO state machine to reduce CPU usage and increase reliability.

Constructor & Destructor Documentation

SmartMotor()

SmartMotor::SmartMotor	(	byte	pwm,
		byte	dir,
		byte	enc_a,
		byte	enc_b,
		bool	invert = false,
		PIO	pio = pio0
	)

Create SmartMotor object, creating all necessary objects.

Parameters

pwm	PWM pin.
dir	Direction pin.
enc_a	Pin A of the encoder.
enc_b	Pin B of the encoder.
invert	Invert motor direction, usuful when motors are mounted opposite to one another.
pio	PIO to use for the encoder. Each PIO can handle up to 4 encoders.

Member Function Documentation

begin()

void SmartMotor::begin

(

)

Initialize SmartMotor and necessary components.

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calibrate()

void SmartMotor::calibrate

(

float

target = 45.f

)

Calibrate the PID controller.

This function will set the PID parameters to values that should work for the motor. The method used is based on Åström–Hägglund tuning method, while using Ziegler-Nichols formulas to compute the gains. Only the Kp and Ki gains are computed while the Kd gain is set to 0 since it doesn't have a positive effect on controlling the motor.

Parameters

target

Target speed to use for calibration.

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getSpeed()

float SmartMotor::getSpeed

(

)

Get the current speed of the motor.

The value is only updated at a fixed rate, defined by DT_ENC, to avoid losing precision.

Returns

float Current speed of the motor between -MAX_SPEED and MAX_SPEED.

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setSpeed()

void SmartMotor::setSpeed

(

float

value

)

Set the desired speed of the motor.

Parameters

value

Desired motor speed between -MAX_SPEED and MAX_SPEED.

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stop()

void SmartMotor::stop

(

)

Stop the motor.

This function will stop the motor and reset the PID.

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update()

void SmartMotor::update

(

)

Update routine, updating the PID and the motor speed.

This function will be executed at a fixed rate, defined by DT_PID, and should therefore be called as often as possible.

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The documentation for this class was generated from the following files:

• lib/SmartMotor/src/SmartMotor.h
• lib/SmartMotor/src/SmartMotor.cpp