Module: dualHingedRigidBodyStateEffector

Executive Summary

Class to represent a solar array of two panels. The first panel is hinged on a single axis to the spacecraft body. The second panel is hinged to the first panel by a parallel axis on the opposite end of the first panel from the spacecraft body.)

Message Connection Descriptions

The following table lists all the module input and output messages. The module msg variable name 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.

../../../../_images/moduleIODualHingedRigidBodyStateEffector.svg — Figure 1: `DualHingedRigidBodyStateEffector()` Module I/O Illustration

Module I/O Messages
Msg Variable Name	Msg Type	Description
motorTorqueInMsg	ArrayMotorTorqueMsgPayload	(Optional) Input message of the two hinge motor torque values
dualHingedRigidBodyOutMsgs	HingedRigidBodyMsgPayload	vector of output message containing the panel 1 and 2 hinge state angle and angle rate
dualHingedRigidBodyConfigLogOutMsgs	SCStatesMsgPayload	vector of output messages containing the panel 1 and 2 inertial position and attitude states

Detailed Module Description

The module PDF Module Description contains further information on this module’s function, as well as testing.

User Guide

This section is to outline the steps needed to setup a Hinged Rigid Body State Effector in python using Basilisk.

Import the dualHingedRigidBodyStateEffector class:

from Basilisk.simulation import dualHingedRigidBodyStateEffector

Create an instantiation of a Dual Hinged Rigid body:

panel1 = dualHingedRigidBodyStateEffector.DualHingedRigidBodyStateEffector()

Define all physical parameters for a Dual Hinged Rigid Body. For example:
```
IPntS1_S1 = [[100.0, 0.0, 0.0], [0.0, 50.0, 0.0], [0.0, 0.0, 50.0]]
```
Do this for all of the parameters for a Dual Hinged Rigid Body seen in the public variables in the .h file.

Define the initial conditions of the states:

panel1.theta1Init = 5*numpy.pi/180.0
panel1.theta1DotInit = 0.0
panel1.theta2Init = 5*numpy.pi/180.0
panel1.theta2DotInit = 0.0

(Optional) Define a unique name for each state:

panel1.nameOfTheta1State = "dualHingedRigidBodyTheta1"
panel1.nameOfTheta1DotState = "dualHingedRigidBodyThetaDot1"
panel1.nameOfTheta2State = "dualHingedRigidBodyTheta2"
panel1.nameOfTheta2DotState = "dualHingedRigidBodyThetaDot2"

Define an optional motor torque input message with panel1.motorTorqueInMsg
The module creates two output messages with the panel angular states. The messages are stored in the vector dualHingedRigidBodyOutMsgs.
The module creates two output messages with each panel inertial position and attitude states. The messages are stored in the vector dualHingedRigidBodyConfigLogOutMsgs.
Add the panel to your spacecraft:
```
scObject.addStateEffector(panel1)
```

Add the module to the task list:

unitTestSim.AddModelToTask(unitTaskName, panel1)

class DualHingedRigidBodyStateEffector : public StateEffector, public SysModel 

#include <dualHingedRigidBodyStateEffector.h>

dual hinged rigid body state effector

Public Functions

DualHingedRigidBodyStateEffector()

~DualHingedRigidBodyStateEffector()

void registerStates(DynParamManager &statesIn): class method

void linkInStates(DynParamManager &states): class method

void updateEffectorMassProps(double integTime): class method

void updateContributions(double integTime, BackSubMatrices &backSubContr, Eigen::Vector3d sigma_BN, Eigen::Vector3d omega_BN_B, Eigen::Vector3d g_N): — Back-sub contributions

void updateEnergyMomContributions(double integTime, Eigen::Vector3d &rotAngMomPntCContr_B, double &rotEnergyContr, Eigen::Vector3d omega_BN_B)

— Energy and momentum calculations

This method is for calculating the contributions of the DHRB state effector to the energy and momentum of the s/c

void computeDerivatives(double integTime, Eigen::Vector3d rDDot_BN_N, Eigen::Vector3d omegaDot_BN_B, Eigen::Vector3d sigma_BN): — Method for each stateEffector to calculate derivatives

void Reset(uint64_t CurrentSimNanos)

This method is used to reset the module.

Returns:: void

void UpdateState(uint64_t CurrentSimNanos)

This method is used so that the simulation will ask DHRB to update messages.

Parameters:: CurrentSimNanos – The current simulation time in nanoseconds
Returns:: void

void writeOutputStateMessages(uint64_t CurrentClock)

This method takes the computed theta states and outputs them to the m messaging system.

Parameters:: CurrentClock – The current simulation time (used for time stamping)
Returns:: void

Public Members

double mass1: [kg] mass of 1st hinged rigid body

double mass2: [kg] mass of 2nd hinged rigid body

double d1: [m] distance from hinge point H1 to hinged rigid body center of mass S1

double d2: [m] distance from hinge point H2 to hinged rigid body center of mass S2

double l1: [m] distance from hinge point H1 to hinged point H2

double k1: [N-m/rad] torsional spring constant of hinge

double k2: [N-m/rad] torsional spring constant of hinge

double c1: [N-m-s/rad] rotational damping coefficient of hinge

double c2: [N-m-s/rad] rotational damping coefficient of hinge

double theta1Init: [rad] Initial hinged rigid body angle for first panel

double theta1DotInit: [rad/s] Initial hinged rigid body angle rate for first panel

double theta2Init: [rad] Initial hinged rigid body angle for second panel

double theta2DotInit: [rad/s] Initial hinged rigid body angle rate for second panel

Eigen::Matrix3d IPntS1_S1: [kg-m^2] Inertia of hinged rigid body about point S in S frame components

Eigen::Matrix3d IPntS2_S2: [kg-m^2] Inertia of hinged rigid body about point S in S frame components

Eigen::Vector3d r_H1B_B: [m] vector pointing from body frame origin to Hinge location

Eigen::Matrix3d dcm_H1B: [-] DCM from body frame to hinge frame

double thetaH2S1: [-] theta offset of H2 frame with respect to S1 frame

std::string nameOfTheta1State: [-] Identifier for the theta state data container

std::string nameOfTheta1DotState: [-] Identifier for the thetaDot state data container

std::string nameOfTheta2State: [-] Identifier for the theta state data container

std::string nameOfTheta2DotState: [-] Identifier for the thetaDot state data container

BSKLogger bskLogger: — BSK Logging

ReadFunctor<ArrayMotorTorqueMsgPayload> motorTorqueInMsg: — (optional) motor torque input message

std::vector<Message<HingedRigidBodyMsgPayload>*> dualHingedRigidBodyOutMsgs: — state output message vector for all panels

std::vector<Message<SCStatesMsgPayload>*> dualHingedRigidBodyConfigLogOutMsgs: panel state config log message vector for all panels

Private Functions

void computePanelInertialStates()

This method computes the panel states relative to the inertial frame

Returns:: void

void prependSpacecraftNameToStates(): class method

Private Members

Eigen::Vector3d r_H1P_P: [m] vector pointing from primary body frame P origin to Hinge 1 location. If a single spacecraft body is modeled than P is the same as B

Eigen::Matrix3d dcm_H1P: — DCM from primary body frame to hinge 1 frame

double u1: [N-m] motor torques on panel 1

double u2: [N-m] motor torques on panel 2

Eigen::Matrix3d rTildeH1B_B: [-] Tilde matrix of rHB_B

Eigen::Matrix3d dcm_S1P: [-] DCM from primary body to S1 frame

Eigen::Matrix3d dcm_S2P: [-] DCM from primary body to S2 frame

Eigen::Vector3d omega_PN_S1: [rad/s] omega_PN in S1 frame components

Eigen::Vector3d omega_PN_S2: [rad/s] omega_PN in S2 frame components

Eigen::Vector3d sHat11_P: [-] unit direction vector for the first axis of the S frame

Eigen::Vector3d sHat12_P: [-] unit direction vector for the second axis of the S frame

Eigen::Vector3d sHat13_P: [-] unit direction vector for the third axis of the S frame

Eigen::Vector3d sHat21_P: [-] unit direction vector for the first axis of the S frame

Eigen::Vector3d sHat22_P: [-] unit direction vector for the second axis of the S frame

Eigen::Vector3d sHat23_P: [-] unit direction vector for the third axis of the S frame

Eigen::Vector3d r_S1P_P: [-] Vector pointing from body origin to CoM of hinged rigid body in P frame comp

Eigen::Vector3d r_S2P_P: [-] Vector pointing from body origin to CoM of hinged rigid body in P frame comp

Eigen::Matrix3d rTildeS1P_P: [-] Tilde matrix of rSP_P

Eigen::Matrix3d rTildeS2P_P: [-] Tilde matrix of rSP_P

Eigen::Vector3d rPrimeS1P_P: [m/s] Body time derivative of rSP_P

Eigen::Vector3d rPrimeS2P_P: [m/s] Body time derivative of rSBP_P

Eigen::Matrix3d rPrimeTildeS1P_P: [-] Tilde matrix of rPrime_SP_P

Eigen::Matrix3d rPrimeTildeS2P_P: [-] Tilde matrix of rPrime_SP_P

Eigen::Matrix3d IS1PrimePntS1_P: [kg-m^2/s] time body derivative IPntS in primary body frame components

Eigen::Matrix3d IS2PrimePntS2_P: [kg-m^2/s] time body derivative IPntS in primary body frame components

Eigen::Vector3d omega_PNLoc_P: [rad/s] local copy of omegaPN

Eigen::Matrix3d omegaTildePNLoc_P: [-] tilde matrix of omegaPN

double theta1: [rad] hinged rigid body angle

double theta1Dot: [rad/s] hinged rigid body angle rate

double theta2: [rad] hinged rigid body angle

double theta2Dot: [rad/s] hinged rigid body angle rate

Eigen::Matrix2d matrixADHRB: [-] term needed for back substitution

Eigen::Matrix2d matrixEDHRB: [-] term needed for back substitution

Eigen::MatrixXd matrixFDHRB

Eigen::MatrixXd matrixGDHRB

Eigen::Vector2d vectorVDHRB

StateData *theta1State: [-] state manager of theta for hinged rigid body

StateData *theta1DotState: [-] state manager of thetaDot for hinged rigid body

StateData *theta2State: [-] state manager of theta for hinged rigid body

StateData *theta2DotState: [-] state manager of thetaDot for hinged rigid body

Eigen::Vector3d r_SN_N[2]: [m] position vector of hinge CM S relative to inertial frame

Eigen::Vector3d v_SN_N[2]: [m/s] inertial velocity vector of S relative to inertial frame

Eigen::Vector3d sigma_SN[2]: — MRP attitude of panel frame S relative to inertial frame

Eigen::Vector3d omega_SN_S[2]: [rad/s] inertial panel frame angular velocity vector

Eigen::MRPd sigma_BN = {0.0, 0.0, 0.0}: Hub/Inertial attitude represented by MRP of body relative to inertial frame.

Eigen::Vector3d omega_BN_B = {0.0, 0.0, 0.0}: Hub/Inertial angular velocity vector in B frame components.

StateData *v_BN_NState: Hub/Inertial velocity vector in inertial frame components.

Eigen::MatrixXd *inertialPositionProperty: [m] r_N inertial position relative to system spice zeroBase/refBase

Eigen::MatrixXd *inertialVelocityProperty: [m] v_N inertial velocity relative to system spice zeroBase/refBase

Eigen::MatrixXd *g_N: [m/s^2] Gravitational acceleration in N frame components

Private Static Attributes

static uint64_t effectorID = 1: [] ID number of this panel