MBsysPy.mbsyspy.mbs_data module

Main class for Multibody systems.

Summary

Define the class MbsData based on the MbsData structure of MBsysC. This class has the functions required to manipulate the Data (set the number of user constraints, set the independent or dependent variables…).

class MBsysPy.mbsyspy.mbs_data.MbsData(name, user_path=None, symbolic_path=None, prj_functions_c=None, prj_lib_path=None)

Bases: object

Class containing geometrical and dynamical information of robotran Mbs.

Variables

• body_id (dict) – Dictionary containing the names of the bodies as keys and their ids as values.

• DonePart (int) – Flag that indicates if the coordinate partitioning module has been executed (default: 0=not done; 1=done).

• DoneEquil (int) – Flag that indicates if the equilibrium module has been executed (default: 0=not done; 1=done).

• DoneModal (int) – Flag that indicates if the modal module has been executed (default: 0=not done; 1=done).

• dpt (numpy.ndarray) – Numpy array containing the coordinates of all anchor points in body fixed frame: [X_i,Y_i,Z_i] = dpt[1:4,i]

• extforce_id (dict) – Dictionary containing the names of the extforces as keys and their ids as values.

• Fl (numpy.ndarray) – Numpy array containing the current values of the forces on each link.

• frc (numpy.ndarray) – Numpy array containing the components of the resultant external forces (in the body fixed frame) applied to the center of mass of each body.

• g (numpy.ndarray) – The 3 gravity components in the inertial frame: g[1:4]=[g_x, g_y, g_z]

• In (numpy.ndarray) – Numpy array containing the inertia tensor component of each body (in the body fixed frame, relative to the center of mass). For body k: In[1:10, k]=[I_11,I_12,I_13,I_21,I_22,I_23,I_31,I_32,I_33]

• joint_id (dict) – Dictionary containing the names of the joints as keys and their ids as values.

• l (numpy.ndarray) – Numpy array containing the center of mass coordinates in the body fixed frame. For body k: l[1:4, k]=[gc_x, gc_y, gc_z]

• lambda_ (numpy.ndarray) – Numpy array containing the values of the Lagrange Multipliers related to the constraints. The sequence is the same sequence as the constraint definition.

• link_id (dict) – Dictionary containing the names of the links as keys and their ids as values.

• lrod (numpy.ndarray) – Numpy array containing the length of each rod.

• m (numpy.ndarray) – Numpy array containing the mass of each body.

• mbs_filename (str) – Path to mbs file including the file with the extension (.mbs).

• mbs_name (str) – Filename of the mbs file (excluding path and “.mbs” extension).

• nbody (int) – Number of bodies in the system. The fictitious bodies are not taken into account.

• Ncons (int) – Number of algebraic constraints.

• nhu (int) – Number of independent constraints.

• njoint (int) – Number of joints in the system.

• Nlink (int) – Number of forces acting between two points of the system.

• Nloopc (int) – Number of loop constraints.

• npt (int) – Number of anchor points.

• nqa (int) – Number of actuated articulations.

• nqc (int) – Number of driven articulations, it includes qlocked and qdriven.

• nqdriven (int) – Number of driven articulations.

• nqlocked (int) – Number of locked articulations.

• nqu (int) – Number of independent articulations.

• nqv (int) – Number of dependent articulations.

• nqrot (int) – Number of rotational joint (R1, R2 or R3)

• flag_stop (int) – Stop the simulation. For dirdyn, equil, invdyn and solvekin only.

• flag_optim_symb_sin_cos (int) – allow the optimized computation of the sine/cosine w.r.t. the symbolic files. Needs specific symbolic files, i.e. Rtime flag to ON. For advanced use of Robotran Only ! default is 0.

• NRerr (float) – Maximal error on constraint allowed in Newton-Raphson algorithm, default 1.0e-9.

• MAX_NR_ITER (int) – Maximal number of iterations for NR procedure, default 100, default is 100.

• n_rod (int) – Number of rod constraints defined on the system.

• Nsensor (int) – Number of kinematic sensors.

• Nuserc (int) – Number of user constraints.

• Nux (int) – Number of user variable.

• Nxfrc (int) – Number of points where an external force is applied into a body.

• points_id (dict) – Dictionary containing the ids of the anchor points of each bodies. The first key is the body name and the second key is the anchor point name. The retrieve value is the id of the requested anchor point. Example: my_id = mbs_data.points_id[“body_1”][“point_0”]

• process (int) –

  Flag that indicates which module is currently running:

  • 1: partitioning

  • 2: equilibrium

  • 3: direct dynamic

  • 4: modal

  • 5: inverse kinematic

  • 6: inverse dynamic

  At loading the process is set to 1.

• flag_stop – Stop the simulation. For dirdyn, equil, invdyn and solvekin only.

• flag_safety_checks (int) – Flag to activate safety checks everywhere in mbsysc core. Faster computation if this flag is put to 0. default = 1.

• zero_division_thrs (float) – Value from which a warning is raised if a division by zero (or close to) occurs. default 1.0e-9.

• project_path (str) – Path to the mbs project folder.

• q (numpy.ndarray) – Numpy array containing the current values of the generalized coordinates.

• q0 (numpy.ndarray) – Numpy array containing the initial values of the generalized coordinates.

• qa (numpy.ndarray of int) – Numpy array of integers containing the indices of actuated articulations (only for inverse dynamic). Those articulations are controlled by an actuator.

• Qa (numpy.ndarray) – Numpy array containing the value of actuation forces.

• qc (numpy.ndarray of int) – Numpy array of integers containing the indices of driven (locked and driven) articulations.

• Qc (numpy.ndarray) – Numpy array containing the value of joint force introduced in driven joints to respect the user function. The driven forces/torques are saved in the entries given by index vector ‘qc’.

• qd (numpy.ndarray) – Numpy array containing the current values of the generalized velocities.

• qd0 (numpy.ndarray) – Numpy array containing the initial values of the generalized velocities.

• qdd (numpy.ndarray) – Numpy array containing the current values of the generalized accelerations.

• qdd0 (numpy.ndarray) – Numpy array containing the initial values of the generalized accelerations.

• q_sin (numpy.ndarray) – Array with the sine values of the generalized coordinates, if rotational (if translational, contains ‘-2.0’), size = 1 x njoint

• q_cos (numpy.ndarray) – Array with the cosine values of the generalized coordinates, if rotational (if translational, contains ‘-2.0’), size = 1 x njoint

• qdriven (numpy.ndarray of int) – Numpy array of integers containing the indices of driven articulations. Those articulations are controlled by a user function: q[qdriven]=f(tsim)

• qrot (numpy.ndarray of int) – Numpy array of integers containing the indices of the rotational articulations

• qlocked (numpy.ndarray of int) – Numpy array of integers containing the indices of locked articulations. Those articulations have a constant position defined by the user: q[qlocked]=cte

• Qq (numpy.ndarray) – Numpy array containing the values of the joint forces.

• qu (numpy.ndarray of int) – Numpy array of integers containing the indices of the independent articulations.

• qv (numpy.ndarray of int) – Numpy array of integers containing the indices of the dependent articulations.

• sensor_id (dict) – Dictionary containing the names of the sensors as keys and their ids as values.

• sensors (list of MbsSensor) – List containing one instance of MbsSensor (without defined id). User can append as many as needed sensor in the list. Sensors defined in this list can be used by the user for various computation.

• SWr (numpy.ndarray) –

  Numpy array containing the Swr vector for each external forces. for force k, Swr[k,1:10] = [Fx, Fy, Fz, Mx, My, Mz, dxF] with

  • Force components (expressed in the inertial frame) : Fx,Fy,Fz

  • Pure torque components (expressed in the inertial frame) : Mx,My,Mz

  • Application point local coordinates vector (expressed in the body fixed frame): dxF[1:4]

• t0 (scalar) – Initial time of the simulation [s]. For dirdyn and invdyn only. This parameter is set from dirdyn/invyn option at start of time simulation.

• tf (scalar) – Final time of the simulation [s]. For dirdyn and invdyn only. This parameter is set from dirdyn/invyn option at start of time simulation.

• trq (numpy.ndarray) – Numpy array containing the components of the resultant external torques (pure torque and couple produced by forces displacement in the body fixed frame) applied to each body.

• tsim (scalar) – The time value.

• user_model (dict) – Dictionary containing the names of the user models as keys and a second dictionary with their parameters as values. The second dictionary contains the names of the parameters as keys and their values as values

• ux (numpy.ndarray) – Numpy array containing the values of the user variables.

• ux0 (numpy.ndarray) – Numpy array containing the initial values of the user variables.

• uxd (numpy.ndarray) – Numpy array containing the values of the time derivative of the user variables.

• xfidpt (numpy.ndarray of int) – Numpy array of integers containing the indices of the points defined as force application points.

• Z (numpy.ndarray) – Numpy array containing the current values of the distances between of the points of a link.

• Zd (numpy.ndarray) – Numpy array containing the current values of the speed (spreading) between of the points of a link.

• opt_load_c (int) –

  MBsysPy specific flag indicating if the project user and/or symbolic function are python modules or c-libraries:

  • 0: Symbolic and user functions are Python modules.

  • 1: Symbolic functions are loaded from a C library while and user functions are Python modules.

  • 2: Symbolic and user functions are loaded from C libraries.

Examples

Here are some basic usages.

>>> mbs_data = MBsysPy.MbsData("../dataR/ExampleProject.mbs")
>>> mbs_data.user_model["MyUserModel"]["MyScalar"] = 3.0
>>> mbs_msg(mbs_data.user_model["MyUserModel"]["MyScalar"])
    3.0
>>> # Get a copy of the scalar
>>> a = mbs_data.user_model["MyUserModel"]["MyScalar"]
>>> a = 2
>>> mbs_msg(mbs_data.user_model["MyUserModel"]["MyScalar"])
    3.0
>>> print(mbs_data.user_model["MyUserModel"]["MyVector"])
    array([1.0, 3.0])
>>> mbs_data.user_model["MyUserModel"]["MyVector"] = [1.0, 2.0]
>>> print(mbs_data.user_model["MyUserModel"]["MyVector"])
    array([1.0, 2.0])
>>> b = mbs_data.user_model["MyUserModel"]["MyVector"]
>>> b[1] = 10.0
>>> print(mbs_data.user_model["MyUserModel"]["MyVector"])
    array([1.0, 10.0])
>>> b = np.array([2.0, 4.0])
>>> print(mbs_data.user_model["MyUserModel"]["MyVector"])
    array([1.0, 10.0])

The usage of C-structures is a bit more complex. This is mainly used in the case of using a external C-library doing computation on the structure. Such structures must be allocated by the user, either in the c function user_load_post() (requires ‘prj_functions_c=”SU”’) or in python script.

it is assumed that the user model [‘um’][‘struct’] is dedicated to structure named ‘my_struc’.

>>> import ctypes
>>> class MyStruct(ctypes.Structure):
...     _fields_ = [("x", ctypes.c_int),
...                 ("y", ctypes.c_int)]
...
>>> my_struct_ptr = ctypes.pointer(MyStruct(10, 20))
>>> mbs_data.user_model['um']['struct'] = my_struct_ptr
... # If using C library for user function, the structure is ready to use.
... # To retrieve the structure object (and not the pointer to it) and contents
... # for further modifications see next lines.
>>> my_struct = MyStruct.from_address(mbs_data.user_model['um']['struct'])
>>> my_struct.x = 127

In this example, a pointer to MyStruct instance was created. However the python object of the structure is retrieved, allowing easy fields access.

Attributes

DoneEquil

Access to DoneEquil attribute (read-write).

DoneModal

Access to DoneModal attribute (read-only).

DonePart

Access to DonePart attribute (read-only).

Fl

Access to Fl attribute, only value in the vector can be written.

In

Access to In attribute, only value in the matrix can be written.

Jac_user

Access to Jac_user attribute, only value in the matrix can be written.

MAX_NR_ITER

Access to MAX_NR_ITER attribute (read-write).

NRerr

Access to NRerr attribute (read-write).

Ncons

Access to Ncons attribute (read-only).

Nlink

Access to Nlink attribute (read-only).

Nlink3D

Access to Nlink3D attribute (read-only).

Nloopc

Access to Nloopc attribute (read-only).

Nsensor

Access to Nsensor attribute (read-only).

Nuser_model

Access to Nuser_model attribute (read-only).

Nuserc

Access to Nuserc attribute (read-only).

Nux

Access to Nux attribute (read-only).

Nxfrc

Access to Nxfrc attribute (read-only).

Qa

Access to Qa attribute, only value in the vector can be written.

Qc

Access to Qc attribute, only value in the vector can be written.

Qq

Access to Qq attribute, only value in the vector can be written.

SWr

Access to SWr attribute, only value in the matrix can be written.

Z

Access to Z attribute, only value in the vector can be written.

Zd

Access to Zd attribute, only value in the vector can be written.

build_path

Access to build_path attribute (read-only).

dpt

Access to dpt attribute, only value in the matrix can be written.

flag_optim_symb_sin_cos

Access to flag_optim_symb_sin_cos attribute (read-write).

flag_safety_checks

Access to flag_safety_checks attribute (read-write).

flag_stop

Access to flag_stop attribute (read-write).

frc

Access to frc attribute, only value in the matrix can be written.

g

Access to g attribute, only value in the vector can be written.

hu

Access to hu attribute, values should not be modified.

jdqd_user

Access to jdqd_user attribute, only value in the vector can be written.

l

Access to l attribute, only value in the matrix can be written.

l3DWr

Access to l3DWr attribute, only value in the matrix can be written.

lambda_

Access to lambda_ attribute, only value in the vector can be written.

lrod

Access to lrod attribute, only value in the vector can be written.

m

Access to m attribute, only value in the vector can be written.

mbs_filename

Access to mbs_filename attribute (read-only).

mbs_name

Access to mbs_name attribute (read-only).

n_rod

Access to n_rod attribute (read-only).

nbody

Access to nbody attribute (read-only).

nhu

Access to nhu attribute (read-only).

njoint

Access to njoint attribute (read-only).

npt

Access to npt attribute (read-only).

nqa

Access to nqa attribute (read-only).

nqc

Access to nqc attribute (read-only).

nqdriven

Access to nqdriven attribute (read-only).

nqlocked

Access to nqlocked attribute (read-only).

nqrot

Access to nqrot attribute (read-only).

nqu

Access to nqu attribute (read-only).

nqv

Access to nqv attribute (read-only).

process

Access to process attribute (read-write).

project_path

Access to project_path attribute (read-only).

q

Access to q attribute, only value in the vector can be written.

q0

Access to q0 attribute, only value in the vector can be written.

q_cos

Access to q_cos attribute, values should not be modified.

q_sin

Access to q_sin attribute, values should not be modified.

qa

Access to qa attribute, values should not be modified.

qc

Access to qc attribute, values should not be modified.

qd

Access to qd attribute, only value in the vector can be written.

qd0

Access to qd0 attribute, only value in the vector can be written.

qdd

Access to qdd attribute, only value in the vector can be written.

qdd0

Access to qdd0 attribute, only value in the vector can be written.

qdriven

Access to qdriven attribute, values should not be modified.

qlocked

Access to qlocked attribute, values should not be modified.

qrot

Access to qrot attribute, values should not be modified.

qu

Access to qu attribute, values should not be modified.

qv

Access to qv attribute, values should not be modified.

t0

Access to t0 attribute (read-write).

tf

Access to tf attribute (read-write).

trq

Access to trq attribute, only value in the matrix can be written.

tsim

Access to tsim attribute (read-write).

udd

Access to udd attribute, only value in the vector can be written.

ux

Access to ux attribute, only value in the vector can be written.

ux0

Access to ux0 attribute, only value in the vector can be written.

uxd

Access to uxd attribute, only value in the vector can be written.

xfidpt

Access to xfidpt attribute, values should not be modified.

zero_division_thrs

Access to zero_division_thrs attribute (read-write).

Methods

define_output_vector(self, label, size)	Initialize the memory for a vector as output.
empty_qa(self)	Remove all joints from the actuated partition.
exe_dirdyn(self, **kwargs)	Run a dirdyn module with a specified set of options.
exe_equil(self, **kwargs)	Run a equil module with a specified set of options.
exe_invdyn(self, **kwargs)	Run a invdyn module with a specified set of options.
exe_modal(self, **kwargs)	Run a modal module with a specified set of options.
exe_part(self, **kwargs)	Run a partitioning module with the specified set of options.
exe_solvekin(self, **kwargs)	Run a solvekin module with a specified set of options.
load_state(self[, baseFileName, …])	Load a state to MbsData instance from files for specific time.
print_joint_configuration(self)	Print the joint configuration.
reset(self[, verbose])	Reset mbs_data fields to its inital value.
set_nb_userc(self, nb)	Set the number of user constraints.
set_output(self, value, label)	Save a value during time integration.
set_output_value(self, value, val_index, label)	Send a value at a specific location of an output vector.
set_output_vector(self, vec, label)	Send an entire vector as output.
set_qa(self, indices)	Set the specified joints as actuated.
set_qdriven(self, indices)	Set the specified joints as driven.
set_qu(self, indices)	Set the specified joints as independent.
set_qv(self, indices)	Set the specified joints as dependent.
unset_qa(self, indices)	Remove the specified joints from the actuated joints.

property DoneEquil

Access to DoneEquil attribute (read-write).

property DoneModal

Access to DoneModal attribute (read-only).

property DonePart

Access to DonePart attribute (read-only).

property Fl

Access to Fl attribute, only value in the vector can be written.

property In

Access to In attribute, only value in the matrix can be written.

property Jac_user

Access to Jac_user attribute, only value in the matrix can be written.

property MAX_NR_ITER

Access to MAX_NR_ITER attribute (read-write).

property NRerr

Access to NRerr attribute (read-write).

property Ncons

Access to Ncons attribute (read-only).

property Nlink

Access to Nlink attribute (read-only).

property Nlink3D

Access to Nlink3D attribute (read-only).

property Nloopc

Access to Nloopc attribute (read-only).

property Nsensor

Access to Nsensor attribute (read-only).

property Nuser_model

Access to Nuser_model attribute (read-only).

property Nuserc

Access to Nuserc attribute (read-only).

property Nux

Access to Nux attribute (read-only).

property Nxfrc

Access to Nxfrc attribute (read-only).

property Qa

Access to Qa attribute, only value in the vector can be written.

property Qc

Access to Qc attribute, only value in the vector can be written.

property Qq

Access to Qq attribute, only value in the vector can be written.

property SWr

Access to SWr attribute, only value in the matrix can be written.

property Z

Access to Z attribute, only value in the vector can be written.

property Zd

Access to Zd attribute, only value in the vector can be written.

__init__(self, name, user_path=None, symbolic_path=None, prj_functions_c=None, prj_lib_path=None)

Load a specific *.mbs file into a MbsData class instance.

Parameters

• name (str) – The path to the .mbs file to load, including the file extension.

• user_path (str, optional) – The path to the folder containing the user functions if the default project structure are not used.

• symbolic_path (str, optional) – The path to the folder containing the symbolic functions if the default project structure are not used.

• prj_functions_c (None or str, optional) – Option to load some of the project functions from the project C library. Accepted values are:

  • None : All project function are defined in python

  • “symbolic_only” or “S” : Symbolic function comes from C library

  • “symbolic_and_user” or “SU” : Symbolic and user functions come from C library

  default is None

• prj_lib_path (None or str, optional) – Required if ‘prj_functions_c’ is not None - In Linux, it gives the location of the folder containing the

  “symbolicR/” and, or “userfctR/” folders. Each one of the subfolder have to contain the corresponding library (ie: libProject_symbolic.so).

  • In Windows, it gives the location of the folder containing the project libraries (Project_symbolic.dll and/or Project_userfct.dll).

  • In MacOs the expected behavior is the same as Linux. It must be tested.

  default is None

Returns

out – A loaded mbs file in a MbsData instance.

Return type

MBsysPy.MbsData

property build_path

Access to build_path attribute (read-only).

define_output_vector(self, label, size)

Initialize the memory for a vector as output.

This function must be called in the user init function dedicated to an analysis module. The value are defined during the computation thank to the function ‘set_output_vector()’ or ‘set_output_value()’

Parameters

• label (str) – The name of the output. It is used as part of the filename and as identifier when filling the values in the output.

• size (int) – The size of the output vector, which correspond to the maximum value to be saved at each time step.

Notes

In case of error, ‘MbsData.flag_stop’ is set to 1 and the return value of the function is -2 or less. Reset the ‘MbsData.flag_stop’ to 0 if you want to start again a new Robotran module instance. A returned value of “-1” means that the output are currently disable.

Returns

status – Status of the operation, negative if an error occurred.

Return type

int

property dpt

Access to dpt attribute, only value in the matrix can be written.

empty_qa(self)

Remove all joints from the actuated partition.

exe_dirdyn(self, **kwargs)

Run a dirdyn module with a specified set of options.

Also run a partitioning module if needed. Partioning options are set to default values expect rowperm = 1

Parameters

kwargs – Options to user for the analysis (see ‘set_options’ in MbsDirdyn).

Returns

results – This object contains the results of the dirdyn analysis.

Return type

MbsResults instance

exe_equil(self, **kwargs)

Run a equil module with a specified set of options.

Also run a partitioning module if needed. Partioning options are set to default values expect rowperm = 1

Parameters

kwargs – Options to user for the analysis (see ‘set_options’ in MbsEquil).

Returns

results – This object contains the results of the dirdyn analysis.

Return type

MbsResults instance

exe_invdyn(self, **kwargs)

Run a invdyn module with a specified set of options.

Also run a partitioning module if needed. Partioning options are set to default values expect rowperm = 1

Parameters

kwargs – Options to user for the analysis (see ‘set_options’ in MbsInvdyn).

Returns

results – This object contains the results of the invdyn analysis.

Return type

MbsResults instance

exe_modal(self, **kwargs)

Run a modal module with a specified set of options.

Also run a partitioning module if needed. Partioning options are set to default values expect rowperm = 1

Note: A modal analysis should only be run on a equilibrium configuration.

Parameters

kwargs – Options to user for the analysis (see ‘set_options’ in MbsModal).

Returns

results – This object contains the results of the dirdyn analysis.

Return type

MbsResults instance

exe_part(self, **kwargs)

Run a partitioning module with the specified set of options.

Parameters

kwargs – Options of the partitioning module (see ‘set_options’ in MbsPart).

exe_solvekin(self, **kwargs)

Run a solvekin module with a specified set of options.

Also run a partitioning module if needed. Partioning options are set to default values expect rowperm = 1

Parameters

kwargs – Options to user for the analysis (see ‘set_options’ in MbsSolvekin).

Returns

results – This object contains the results of the solvekin analysis.

Return type

MbsResults instance

property flag_optim_symb_sin_cos

Access to flag_optim_symb_sin_cos attribute (read-write).

property flag_safety_checks

Access to flag_safety_checks attribute (read-write).

property flag_stop

Access to flag_stop attribute (read-write).

property frc

Access to frc attribute, only value in the matrix can be written.

property g

Access to g attribute, only value in the vector can be written.

property hu

Access to hu attribute, values should not be modified.

property jdqd_user

Access to jdqd_user attribute, only value in the vector can be written.

property l

Access to l attribute, only value in the matrix can be written.

property l3DWr

Access to l3DWr attribute, only value in the matrix can be written.

property lambda_

Access to lambda_ attribute, only value in the vector can be written.

load_state(self, baseFileName='dirdyn', result_path='resultsR', time=- 1, files_to_load=['all'])

Load a state to MbsData instance from files for specific time.

If the time specified is not found in the file, the last time step lower than the specification is taken. The fieds tsim, q, qd, qdd, ux, uxd (and q0, qd0, qdd0, ux0) are set.

If a file is not found a warning is generated and the value in memory are kept back.

Parameters

• baseFileName (str) – The path and resfilename containing the state to load. The suffix _q, _qd, _ux.res will be added. default is “dirdyn”

• result_path (str) – The relative path of the result folder from the project folder. default is “resultsR”

• time (float) – The time corresponding to the state to load. defaut is “-1” (last state of the files).

• files_to_load (list of str) –

  List of the results files to load among:

  • ‘all’: load all results files

  • ‘q’: load the generalized coordinates

  • ‘qd’: load the generalized velocities

  • ‘qdd’: load the generalized acceleration

  • ‘user’: load the user state variables

  • ‘userd’: load the derivative of the user state variables.

  default is “[‘all’]”.

property lrod

Access to lrod attribute, only value in the vector can be written.

property m

Access to m attribute, only value in the vector can be written.

property mbs_filename

Access to mbs_filename attribute (read-only).

property mbs_name

Access to mbs_name attribute (read-only).

property n_rod

Access to n_rod attribute (read-only).

property nbody

Access to nbody attribute (read-only).

property nhu

Access to nhu attribute (read-only).

property njoint

Access to njoint attribute (read-only).

property npt

Access to npt attribute (read-only).

property nqa

Access to nqa attribute (read-only).

property nqc

Access to nqc attribute (read-only).

property nqdriven

Access to nqdriven attribute (read-only).

property nqlocked

Access to nqlocked attribute (read-only).

property nqrot

Access to nqrot attribute (read-only).

property nqu

Access to nqu attribute (read-only).

property nqv

Access to nqv attribute (read-only).

print_joint_configuration(self)

Print the joint configuration.

Print qu, qv, qc, qdriven, qlocked, qa.

Returns

Return type

None.

property process

Access to process attribute (read-write).

property project_path

Access to project_path attribute (read-only).

property q

Access to q attribute, only value in the vector can be written.

property q0

Access to q0 attribute, only value in the vector can be written.

property q_cos

Access to q_cos attribute, values should not be modified.

property q_sin

Access to q_sin attribute, values should not be modified.

property qa

Access to qa attribute, values should not be modified.

property qc

Access to qc attribute, values should not be modified.

property qd

Access to qd attribute, only value in the vector can be written.

property qd0

Access to qd0 attribute, only value in the vector can be written.

property qdd

Access to qdd attribute, only value in the vector can be written.

property qdd0

Access to qdd0 attribute, only value in the vector can be written.

property qdriven

Access to qdriven attribute, values should not be modified.

property qlocked

Access to qlocked attribute, values should not be modified.

property qrot

Access to qrot attribute, values should not be modified.

property qu

Access to qu attribute, values should not be modified.

property qv

Access to qv attribute, values should not be modified.

reset(self, verbose=False)

Reset mbs_data fields to its inital value.

The following fields are reset according to the values storied in the field in parentheses:

• MbsData.q (MbsData.q0)

• MbsData.qd (MbsData.qd0)

• MbsData.qdd (MbsData.qdd0)

• MbsData.ux (MbsData.ux0)

• MbsData.Qq (filled with 0)

• MbsData.Qa (filled with 0)

• MbsData.Qc (filled with 0)

• MbsData.tsim (MbsData.t0)

Parameters

verbose (bool, optional) – Set to ‘True’ to mbs_msg resetting validation message. default is False

set_nb_userc(self, nb)

Set the number of user constraints.

Parameters

nb (int) – The number of user constraints.

set_output(self, value, label)

Save a value during time integration.

Parameters

• value (float) – Value to be saved.

• label (str) – The name of the output, also used as part as the output filename.

Notes

In case of error, ‘MbsData.flag_stop’ is set to 1 and the return value of the function is -2 or less. Reset the ‘MbsData.flag_stop’ to 0 if you want to start again a new Robotran module instance. A returned value of “-1” means that the output are currently disable.

Returns

status – Status of the operation, negative if an error occurred.

Return type

int

set_output_value(self, value, val_index, label)

Send a value at a specific location of an output vector.

Parameters

• value (float) – Value to be saved.

• val_index (int) – index in the output vector where the value must be saved. This index must be at least 1 and maximum equal to the size specified with the function ‘define_output_vector()’.

• label (str) – The name of the output. It must have been defined with the function

• ‘define_output_vector()’.

Notes

In case of error, ‘MbsData.flag_stop’ is set to 1 and the return value of the function is -2 or less. Reset the ‘MbsData.flag_stop’ to 0 if you want to start again a new Robotran module instance. A returned value of “-1” means that the output are currently disable.

Returns

status – Status of the operation, negative if an error occurred.

Return type

int

set_output_vector(self, vec, label)

Send an entire vector as output.

The size of ‘vec’ must be equal to the size defined in the function ‘define_output_vector()’.

Parameters

• vec (list or numpy.ndarray) – Value to be saved as a list or a numpy array.

• label (str) – The name of the output. It must have been defined with the function

• ‘define_output_vector()’.

Notes

In case of error, ‘MbsData.flag_stop’ is set to 1 and the return value of the function is -2 or less. Reset the ‘MbsData.flag_stop’ to 0 if you want to start again a new Robotran module instance. A returned value of “-1” means that the output are currently disable.

Returns

status – Status of the operation, negative if an error occurred.

Return type

int

set_qa(self, indices)

Set the specified joints as actuated.

Actuated joints are only used by equilibrium analysis (in some cases) and inverse dynamics. Actuated joint are also member of one of the other partition (independent or dependent).

Parameters

indices (int, list or numpy.ndarray of int) – The ids of the joints to set as actuated.

set_qdriven(self, indices)

Set the specified joints as driven.

Parameters

indices (int, list or numpy.ndarray of int) – The ids of the joints to set as driven.

set_qu(self, indices)

Set the specified joints as independent.

Parameters

indices (int, list or numpy.ndarray of int) – The ids of the joints to set as independent.

set_qv(self, indices)

Set the specified joints as dependent.

Parameters

indices (int, list or numpy.ndarray of int) – The ids of the joints to set as dependent.

property t0

Access to t0 attribute (read-write).

property tf

Access to tf attribute (read-write).

property trq

Access to trq attribute, only value in the matrix can be written.

property tsim

Access to tsim attribute (read-write).

property udd

Access to udd attribute, only value in the vector can be written.

unset_qa(self, indices)

Remove the specified joints from the actuated joints.

Parameters

indices (int, list or numpy.ndarray of int) – The ids of the joints to be removed from the actuated list.

property ux

Access to ux attribute, only value in the vector can be written.

property ux0

Access to ux0 attribute, only value in the vector can be written.

property uxd

Access to uxd attribute, only value in the vector can be written.

property xfidpt

Access to xfidpt attribute, values should not be modified.

property zero_division_thrs

Access to zero_division_thrs attribute (read-write).