Pre/Post-Processing

UR3 Robot Arm

Configuration files:

  • FENGSim/starter/mbdyn/robot/robot_arm.mbd

This example is for a 6-dof robot arm, though without the end effector, the final dof is disregarded.

To define angle constraints using time-dependent scalar funtions in robot_arm.mbd:

#-----------------------------------------------------------------------------
# Scalar Functions
scalar function: "Fun_Motor_JoTotp_Stage",
multilinear,
    0.0, 0.0,
    1.0, 0.0,
    2.0, -1./2.*pi;

scalar function: "Fun_Motor_JoTotj_Stage_UpperArm",
multilinear,
    0.0, 0.0,
    1.0, 0.0,
    2.0, -2./6.*pi;

scalar function: "Fun_Motor_JoTotj_UpperArm_LowerArm",
multilinear,
    0.0, 0.0,
    1.0, 0.0,
    2.0, -4./6.*pi;

scalar function: "Fun_Motor_JoTotj_LowerArm_Wrist",
multilinear,
    0.0, 0.0,
    1.0, 0.0,
    2.0, 1./6.*pi;

scalar function: "Fun_Motor_JoTotj_Wrist_Hand",
multilinear,
    0.0, 0.0,
    1.0, 0.0,
    2.0, pi;

  • Line 7: the first number 2.0 is a time step and the second number -1./2.*pi is an angle value.

Geometry files (base path:FENGSim/starter/mbdyn/robot/):

  • .stp file: UR3.STEP

  • .stl files: down.stl, hand.stl, stage1.stl, stage2.stl, upper.stl, wrist.stl

  • .traj files: ur3.traj, line segments with the pose and velocity values

  • UR3E technical file: ur3e_e-series_datasheets_web.pdf

The parameter (131.05mm) shown in the figure below from ur3e_e-series_datasheets_web.pdf does not match the corresponding one (110.4mm) in UR3.STEP.

alternate text

Results:

  • .mov files: FENGSim/starter/mbdyn/robot/robot_arm.mov

More details for .mov format in Section 2.1 of https://github.com/mmorandi/MBDyn-web/raw/main/userfiles/documents/tutorials.pdf :

  • the node label

  • the three coordinates of the position of the node

  • the three Euler-like angles that define the orientation of the node (following the 1, 2, 3 convention)

  • the three components of the velocity of the node

  • the three components of the angular velocity of the node