Module: rateServoFullNonlinear

Executive Summary

This module implements a nonlinear rate servo control uses the attiude steering message and determine the ADCS control torque vector.

The module PDF Description contains further information on this module’s function, how to run it, as well as testing.

Message Connection Descriptions

The following table lists all the module input and output messages. The module msg connection is set by the user from python. The msg type contains a link to the message structure definition, while the description provides information on what this message is used for.

Module I/O Messages

Msg Variable Name	Msg Type	Description
cmdTorqueOutMsg	CmdTorqueBodyMsgPayload	commanded torque output message
guidInMsg	AttGuidMsgPayload	attitude guidance input message
vehConfigInMsg	VehicleConfigMsgPayload	vehicle configuration input message
rwSpeedsInMsg	RWSpeedMsgPayload	(optional) RW speed input message
rwAvailInMsg	RWAvailabilityMsgPayload	(optional) RW availability input message
rwParamsInMsg	RWArrayConfigMsgPayload	(optional) RW configuration parameter input message
rateSteeringInMsg	RateCmdMsgPayload	commanded rate input message

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Functions

void SelfInit_rateServoFullNonlinear(rateServoFullNonlinearConfig *configData, int64_t moduleID)

selfInit method

Parameters:

• configData – The configuration data associated with this module

• moduleID – The module identifier

Returns:

void

void Update_rateServoFullNonlinear(rateServoFullNonlinearConfig *configData, uint64_t callTime, int64_t moduleID)

This method takes and rate errors relative to the Reference frame, as well as the reference frame angular rates and acceleration, and computes the required control torque Lr.

Parameters:

• configData – The configuration data associated with the servo rate control

• callTime – The clock time at which the function was called (nanoseconds)

• moduleID – The module identifier

Returns:

void

void Reset_rateServoFullNonlinear(rateServoFullNonlinearConfig *configData, uint64_t callTime, int64_t moduleID)

This method performs a complete reset of the module. Local module variables that retain time varying states between function calls are reset to their default values.

Parameters:

• configData – The configuration data associated with the servo rate control

• callTime – The clock time at which the function was called (nanoseconds)

• moduleID – The module identifier

Returns:

void

struct rateServoFullNonlinearConfig

#include <rateServoFullNonlinear.h>

The configuration structure for the rateServoFullNonlinear module.

Public Members

double P

[N*m*s] Rate error feedback gain applied

double Ki

[N*m] Integration feedback error on rate error

double knownTorquePntB_B[3]

[N*m] known external torque in body frame vector components

double integralLimit

[N*m] Integration limit to avoid wind-up issue

uint64_t priorTime

[ns] Last time the attitude control is called

double z[3]

[rad] integral state of delta_omega

double ISCPntB_B[9]

[kg m^2] Spacecraft Inertia

RWArrayConfigMsgPayload rwConfigParams

[-] struct to store message containing RW config parameters in body B frame

CmdTorqueBodyMsg_C cmdTorqueOutMsg

commanded torque output message

AttGuidMsg_C guidInMsg

attitude guidance input message

VehicleConfigMsg_C vehConfigInMsg

vehicle configuration input message

RWSpeedMsg_C rwSpeedsInMsg

(optional) RW speed input message

RWAvailabilityMsg_C rwAvailInMsg

(optional) RW availability input message

RWArrayConfigMsg_C rwParamsInMsg

(optional) RW configuration parameter input message

RateCmdMsg_C rateSteeringInMsg

commanded rate input message

BSKLogger *bskLogger

BSK Logging.