Encoder class with helper functions, derived from QEI. More...

#include <encoder.h>

Inheritance diagram for Encoder:

Collaboration diagram for Encoder:

Public Member Functions
	Encoder (PinName A, PinName B)
	Constructor. More...

void	start ()
	Start the routine to measure pulses periodically. More...

int	getCounter () const
	Get current running sum of pulses. More...

void	resetCounter ()
	Reset the running sum of pulses used for getDistance(). More...

double	getVelocity () const
	Get current velocity. More...

double	getDistance () const
	Get total distance travelled. More...

double	getPPS () const
	Get current pulses per unit second (PPS). More...

Public Member Functions inherited from QEI
	QEI (PinName channelA, PinName channelB, PinName index, int pulsesPerRev, Encoding encoding=X2_ENCODING)
	Constructor. More...

void	reset (void)
	Reset the encoder. More...

int	getCurrentState (void)
	Read the state of the encoder. More...

int	getInvalidCount (void)
	Read the number of invalid counts. More...

int	getPulses (void)
	Read the number of pulses recorded by the encoder. More...

int	getRevolutions (void)
	Read the number of revolutions recorded by the encoder on the index channel. More...

void	setPulses (int newCount)
	Set the current pulse count in case you want to init it. More...

void	setRevolutions (int newRevs)
	Set the current revolution count in case you want to init it. More...

Static Public Member Functions
static double	getAverageAngular (const Encoder &right_encoder, const Encoder &left_encoder)
	Get average of angular velocity between two wheels. More...

static double	getAverageVelocity (const Encoder &right_encoder, const Encoder &left_encoder)
	Get average of linear velocity between two wheels. More...

static double	getAverageDistance (const Encoder &right_encoder, const Encoder &left_encoder)
	Get average of total distance between two wheels. More...

Static Public Attributes
static constexpr double	CIRCUMFERENCE = DIAMETER * M_PI
	Circumference of the wheel. More...

static constexpr double	FULL_ROTATION_SIDE_PIVOT = 2.0 * M_PI * WHEEL_DISTANCE
	Distance covered in full rotation when turning only using one wheel. More...

static constexpr double	FULL_ROTATION_CENTER_PIVOT = M_PI * WHEEL_DISTANCE
	Distance covered in full rotation when turning using both wheels. More...

Private Member Functions
void	m_calculateSpeed (const double &time_elapsed)
	Calculate the velocity of the wheel. More...

void	m_stop ()
	Stop the timer and get current pulse. More...

Private Attributes
volatile int	m_start_pulse
	Counter for previous pulse. More...

volatile int	m_end_pulse
	Counter for latest pulse. More...

volatile int	m_pulse_width
	Counter for pulse difference. More...

volatile int	m_pulse_counter
	Counter for total pulses from start. More...

volatile double	m_pulse_per_sec
	Pulse per unit second. More...

volatile double	m_velocity
	Velocity. More...

Timer	m_t
	Timer for high-precision clocking. More...

Timeout	m_to
	Timeout to interrupt every POLLING_PERIOD. More...

Additional Inherited Members
Public Types inherited from QEI
enum	Encoding { X2_ENCODING , X4_ENCODING }

typedef enum QEI::Encoding	Encoding

Detailed Description

Encoder class with helper functions, derived from QEI.

This class call a function periodically to measure the speed of wheel. It features return values in terms of pulse per second, distance, and velocity.

Constructor & Destructor Documentation

◆ Encoder()

Encoder::Encoder	(	PinName	A,
		PinName	B
	)

Constructor.

Construct a new Encoder object.

Parameters

A	Channel A pin.
B	Channel B pin.

Member Function Documentation

◆ start()

void Encoder::start ( )

Start the routine to measure pulses periodically.

Start timer and get current pulse. Timeout for every POLLING_PERIOD.

◆ getCounter()

int Encoder::getCounter ( ) const

Get current running sum of pulses.

Returns: int Total number of pulses after start.

◆ resetCounter()

void Encoder::resetCounter ( )

Reset the running sum of pulses used for getDistance().

◆ getVelocity()

double Encoder::getVelocity ( ) const

Get current velocity.

Returns: double Velocity of the wheel.

◆ getDistance()

double Encoder::getDistance ( ) const

Get total distance travelled.

The distance can be calculated from known values of COUNTS_PER_REV and CIRCUMFERENCE which is defined by \(distance = \frac{pulse\ counter\ \cdot\ cirmcumference}{2\ \cdot\ CPR}\\\)

Returns: double Total distance (metre) travelled by the wheel.

◆ getPPS()

double Encoder::getPPS ( ) const

Get current pulses per unit second (PPS).

Returns: double PPS of the wheel.

◆ getAverageAngular()

static double Encoder::getAverageAngular	(	const Encoder &	right_encoder,
		const Encoder &	left_encoder
	)

static

Get average of angular velocity between two wheels.

+ve indicates tilting to the right. -ve indicates tilting to the left.

Parameters

right_encoder	Right Wheel encoder
left_encoder	Left Wheel encoder

Returns: double Angular velocity (deg/s) of the buggy.

◆ getAverageVelocity()

static double Encoder::getAverageVelocity	(	const Encoder &	right_encoder,
		const Encoder &	left_encoder
	)

static

Get average of linear velocity between two wheels.

+ve indicates forward direction. -ve indicates reverse direction.

Parameters

right_encoder	Right Wheel encoder.
left_encoder	Left Wheel encoder.

Returns: double Linear velocity (m/s) of the buggy.

◆ getAverageDistance()

static double Encoder::getAverageDistance	(	const Encoder &	right_encoder,
		const Encoder &	left_encoder
	)

static

Get average of total distance between two wheels.

+ve indicates forward direction. -ve indicates reverse direction.

Parameters

right_encoder	Right Wheel encoder.
left_encoder	Left Wheel encoder.

Returns: double Average distance of the buggy.

◆ m_calculateSpeed()

void Encoder::m_calculateSpeed ( const double & time_elapsed )

private

Calculate the velocity of the wheel.

The velocity can be calculated from known values of COUNTS_PER_REV CPR and CIRCUMFERENCE which is defined by \(velocity = \frac{pulse\ width\ \cdot\ cirmcumference}{2\ \cdot\ CPR \ \cdot \ time}\\\)

Parameters

time_elapsed The elapsed time between two pulse count.

◆ m_stop()

void Encoder::m_stop ( )

private

Stop the timer and get current pulse.

Member Data Documentation

◆ m_start_pulse

volatile int Encoder::m_start_pulse

private

Counter for previous pulse.

◆ m_end_pulse

volatile int Encoder::m_end_pulse

private

Counter for latest pulse.

◆ m_pulse_width

volatile int Encoder::m_pulse_width

private

Counter for pulse difference.

◆ m_pulse_counter

volatile int Encoder::m_pulse_counter

private

Counter for total pulses from start.

◆ m_pulse_per_sec

volatile double Encoder::m_pulse_per_sec

private

Pulse per unit second.

◆ m_velocity

volatile double Encoder::m_velocity

private

Velocity.

◆ m_t

Timer Encoder::m_t

private

Timer for high-precision clocking.

◆ m_to

Timeout Encoder::m_to

private

Timeout to interrupt every POLLING_PERIOD.

◆ CIRCUMFERENCE

constexpr double Encoder::CIRCUMFERENCE = DIAMETER * M_PI

staticconstexpr

Circumference of the wheel.

◆ FULL_ROTATION_SIDE_PIVOT

constexpr double Encoder::FULL_ROTATION_SIDE_PIVOT = 2.0 * M_PI * WHEEL_DISTANCE

staticconstexpr

Distance covered in full rotation when turning only using one wheel.

◆ FULL_ROTATION_CENTER_PIVOT

constexpr double Encoder::FULL_ROTATION_CENTER_PIVOT = M_PI * WHEEL_DISTANCE

staticconstexpr

Distance covered in full rotation when turning using both wheels.

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

/github/workspace/include/QEI/encoder/encoder.h

Public Member Functions

Static Public Member Functions

Static Public Attributes

Private Member Functions

Private Attributes

Additional Inherited Members

Detailed Description

Constructor & Destructor Documentation

◆ Encoder()

Member Function Documentation

◆ start()

◆ getCounter()

◆ resetCounter()

◆ getVelocity()

◆ getDistance()

◆ getPPS()

◆ getAverageAngular()

◆ getAverageVelocity()

◆ getAverageDistance()

◆ m_calculateSpeed()

◆ m_stop()

Member Data Documentation

◆ m_start_pulse

◆ m_end_pulse

◆ m_pulse_width

◆ m_pulse_counter

◆ m_pulse_per_sec

◆ m_velocity

◆ m_t

◆ m_to

◆ CIRCUMFERENCE

◆ FULL_ROTATION_SIDE_PIVOT

◆ FULL_ROTATION_CENTER_PIVOT