user_Link3DForces module

Module for the definition of user 3D links forces.

user_Link3DForces.user_Link3DForces(PxF, RxF, VxF, OMxF, AxF, OMPxF, mbs_data, tsim, ixF)

Compute the force in the given 3Dlink.

Link 3D are not yet supported in MBsysPy

This function (and its description) may be erroneous

Do not use

A 3D link is defined by it’s starting point A (on body_A) and the ending point B (on body_B).

The force and torque applied on both body is located on point A.

Parameters

  • PxF (numpy.ndarray) – Position vector (index starting at 1) from point A to point B expressed the inertial frame: PxF[1:4] = [P_x, P_y, P_z]

  • RxF (numpy.ndarray) – Rotation matrix (index starting at 1) from body_A frame to the body_B frame: Frame_sbody_B = RxF[1:4,1:4] * Frame_body_A

  • VxF (numpy.ndarray) – Relative velocity vector (index starting at 1) between point A and B expressed in the inertial frame: VxF[1:4] = [V_x, V_y, V_z]

  • OMxF (numpy.ndarray) – Relative angular velocity vector (index starting at 1) between point A and B expressed in the inertial frame: OMxF[1:4] = [OM_x, OM_y, OM_z]

  • AxF (numpy.ndarray) – Relative acceleration vector (index starting at 1) between point A and B expressed in the inertial frame: AxF[1:4] = [A_x, A_y, A_z]

  • OMPxF (numpy.ndarray) – Relative angular acceleration vector (index starting at 1) between point A and B expressed in the inertial frame: OMPxF[1:4] = [OMP_x, OMP_y, OMP_z]

  • mbs_data (MBsysPy.MbsData) – The multibody system associated to this computation.

  • tsim (float) – The current time of the simulation.

  • ixF (int) – The ID identifying the computed 3Dlink.

Returns

Swr – An array of length 7 equal to [0., Fx, Fy, Fz, Mx, My, Mz]. F_# are the forces components expressed in inertial frame. M_# are the torques components expressed in inertial frame.

Return type

numpy.ndarray