pbio/observer: Servo state observer

Luenberger state observer implementation to estimate motor speed. More...

Classes
struct	_pbio_observer_model_t
	Device-type specific constants that describe the motor model. More...
struct	_pbio_observer_settings_t
	Configurable observer settings. More...
struct	_pbio_observer_t
	Motor state observer object. More...

Typedefs
typedef struct _pbio_observer_model_t	pbio_observer_model_t
	Device-type specific constants that describe the motor model. More...
typedef struct _pbio_observer_settings_t	pbio_observer_settings_t
	Configurable observer settings. More...
typedef struct _pbio_observer_t	pbio_observer_t
	Motor state observer object. More...

Functions
void	pbio_observer_reset (pbio_observer_t *obs, const pbio_angle_t *angle)
	Resets the observer to a new angle. More...
void	pbio_observer_get_estimated_state (const pbio_observer_t *obs, int32_t *speed_num, pbio_angle_t *angle_est, int32_t *speed_est)
	Gets the observer state, which is the estimated state of the real system. More...
void	pbio_observer_update (pbio_observer_t *obs, uint32_t time, const pbio_angle_t *angle, pbio_dcmotor_actuation_t actuation, int32_t voltage)
	Predicts next system state and corrects the model using a measurement. More...
bool	pbio_observer_is_stalled (const pbio_observer_t *obs, uint32_t time, uint32_t *stall_duration)
	Checks whether system is stalled by testing how far the estimate is ahead of the measured angle, which is a measure for an unmodeled load. More...
int32_t	pbio_observer_get_feedback_voltage (const pbio_observer_t *obs, const pbio_angle_t *angle)
	Gets observer feedback voltage that keeps it close to measured value. More...
int32_t	pbio_observer_get_max_torque (void)
	Gets the maximum torque for use by user input validators. More...
int32_t	pbio_observer_get_feedforward_torque (const pbio_observer_model_t *model, int32_t rate_ref, int32_t acceleration_ref)
	Calculates the feedforward torque needed to achieve the requested reference rotational speed and acceleration. More...
int32_t	pbio_observer_torque_to_voltage (const pbio_observer_model_t *model, int32_t desired_torque)
	Converts a torque to a voltage based on the given motor model. More...
int32_t	pbio_observer_voltage_to_torque (const pbio_observer_model_t *model, int32_t voltage)
	Converts a voltage to a torque based on the given motor model. More...

Detailed Description

Luenberger state observer implementation to estimate motor speed.

Typedef Documentation

pbio_observer_model_t

typedef struct _pbio_observer_model_t pbio_observer_model_t

Device-type specific constants that describe the motor model.

pbio_observer_settings_t

typedef struct _pbio_observer_settings_t pbio_observer_settings_t

Configurable observer settings.

pbio_observer_t

typedef struct _pbio_observer_t pbio_observer_t

Motor state observer object.

Function Documentation

pbio_observer_get_estimated_state()

void pbio_observer_get_estimated_state	(	const pbio_observer_t *	obs,
		int32_t *	speed_num,
		pbio_angle_t *	angle_est,
		int32_t *	speed_est
	)

Gets the observer state, which is the estimated state of the real system.

Parameters

[in]	obs	The observer instance.
[out]	speed_num	Speed in millidegrees/second as numeric derivative of angle.
[out]	angle_est	Model estimate of angle in millidegrees.
[out]	speed_est	Model estimate of speed in millidegrees/second.

Definition at line 58 of file observer.c.

pbio_observer_get_feedback_voltage()

int32_t pbio_observer_get_feedback_voltage	(	const pbio_observer_t *	obs,
		const pbio_angle_t *	angle
	)

Gets observer feedback voltage that keeps it close to measured value.

Parameters

[in]	obs	The observer instance.
[in]	angle	Measured angle used to correct the model.

Returns

Feedback voltage in mV.

Definition at line 132 of file observer.c.

pbio_observer_get_feedforward_torque()

int32_t pbio_observer_get_feedforward_torque	(	const pbio_observer_model_t *	model,
		int32_t	rate_ref,
		int32_t	acceleration_ref
	)

Calculates the feedforward torque needed to achieve the requested reference rotational speed and acceleration.

Parameters

[in]	model	The observer model instance.
[in]	rate_ref	The reference rate in mdeg/s.
[in]	acceleration_ref	The reference acceleration in mdeg/s/s.

Returns

The feedforward torque in uNm.

Definition at line 250 of file observer.c.

pbio_observer_get_max_torque()

int32_t pbio_observer_get_max_torque

(

void

)

Gets the maximum torque for use by user input validators.

Returns

The maximum torque in uNm.

Definition at line 236 of file observer.c.

pbio_observer_is_stalled()

bool pbio_observer_is_stalled	(	const pbio_observer_t *	obs,
		uint32_t	time,
		uint32_t *	stall_duration
	)

Checks whether system is stalled by testing how far the estimate is ahead of the measured angle, which is a measure for an unmodeled load.

Parameters

[in]	obs	The observer instance.
[in]	time	Wall time.
[out]	stall_duration	For how long it has been stalled.

Returns

True if stalled, false if not.

Definition at line 220 of file observer.c.

pbio_observer_reset()

void pbio_observer_reset	(	pbio_observer_t *	obs,
		const pbio_angle_t *	angle
	)

Resets the observer to a new angle.

Speed and current are reset to zero.

Parameters

[in]	obs	The observer instance.
[in]	angle	Angle to which the observer should be reset.

Definition at line 36 of file observer.c.

pbio_observer_torque_to_voltage()

int32_t pbio_observer_torque_to_voltage	(	const pbio_observer_model_t *	model,
		int32_t	desired_torque
	)

Converts a torque to a voltage based on the given motor model.

Parameters

[in]	model	The observer model instance.
[in]	desired_torque	The torque in uNm.

Returns

The voltage in mV.

Definition at line 267 of file observer.c.

pbio_observer_update()

void pbio_observer_update	(	pbio_observer_t *	obs,
		uint32_t	time,
		const pbio_angle_t *	angle,
		pbio_dcmotor_actuation_t	actuation,
		int32_t	voltage
	)

Predicts next system state and corrects the model using a measurement.

Parameters

[in]	obs	The observer instance.
[in]	time	Wall time.
[in]	angle	Measured angle used to correct the model.
[in]	actuation	Actuation type currently applied to the motor.
[in]	voltage	If actuation type is voltage, this is the payload in mV.

Definition at line 153 of file observer.c.

pbio_observer_voltage_to_torque()

int32_t pbio_observer_voltage_to_torque	(	const pbio_observer_model_t *	model,
		int32_t	voltage
	)

Converts a voltage to a torque based on the given motor model.

Parameters

[in]	model	The observer model instance.
[in]	voltage	The voltage in mV.

Returns

The torque in uNm.

Definition at line 278 of file observer.c.