ur5x4.py

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"""
Load 4 times the UR5 model, plus a plate object on top of them, to feature a simple
parallel robot.
No optimization, this file is just an example of how to load the models.
"""
 
from pathlib import Path
 
import numpy as np
from pinocchio import SE3
from pinocchio.robot_wrapper import RobotWrapper
from pinocchio.utils import eye, rotate, se3ToXYZQUATtuple, urdf, zero
 
PKG = Path("/opt/openrobots/share")
URDF = PKG / "ur5_description/urdf/ur5_gripper.urdf"
 
 
def loadRobot(M0, name):
    """
    This function load a UR5 robot n a new model, move the basis to placement <M0>
    and add the corresponding visuals in gepetto viewer with name prefix given by string
    <name>.
    It returns the robot wrapper (model,data).
    """
    robot = RobotWrapper(urdf, [PKG])
    robot.model.jointPlacements[1] = M0 * robot.model.jointPlacements[1]
    robot.visual_model.geometryObjects[0].placement = (
        M0 * robot.visual_model.geometryObjects[0].placement
    )
    robot.visual_data.oMg[0] = M0 * robot.visual_data.oMg[0]
    robot.initDisplay(loadModel=True, viewerRootNodeName="world/" + name)
    return robot
 
 
robots = []
# Load 4 Ur5 robots, placed at 0.3m from origin in the 4 directions x,y,-x,-y.
Mt = SE3(eye(3), np.array([0.3, 0, 0]))  # First robot is simply translated
for i in range(4):
    robots.append(
        loadRobot(SE3(rotate("z", np.pi / 2 * i), zero(3)) * Mt, "robot%d" % i)
    )
 
# Set up the robots configuration with end effector pointed upward.
q0 = np.array([np.pi / 4, -np.pi / 4, -np.pi / 2, np.pi / 4, np.pi / 2, 0])
for i in range(4):
    robots[i].display(q0)
 
# Add a new object featuring the parallel robot tool plate.
gepettoViewer = robots[0].viewer.gui
w, h, d = 0.25, 0.25, 0.005
color = [red, green, blue, transparency] = [1, 1, 0.78, 1.0]
gepettoViewer.addBox("world/toolplate", w, h, d, color)
Mtool = SE3(rotate("z", 1.268), np.array([0, 0, 0.77]))
gepettoViewer.applyConfiguration("world/toolplate", se3ToXYZQUATtuple(Mtool))
gepettoViewer.refresh()