.. _examples-rigidbodytutorial3withmarkers: ******************************** rigidBodyTutorial3withMarkers.py ******************************** You can view and download this file on Github: `rigidBodyTutorial3withMarkers.py `_ .. code-block:: python :linenos: #+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ # This is an EXUDYN example # # Details: 3D rigid body tutorial with 2 bodies and revolute joints, using Marker-style approach # # Author: Johannes Gerstmayr # Date: 2021-08-05 # Date: 2024-06-04 (updated to MainSystem Python extensions) # # Copyright:This file is part of Exudyn. Exudyn is free software. You can redistribute it and/or modify it under the terms of the Exudyn license. See 'LICENSE.txt' for more details. # #+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++ import exudyn as exu from exudyn.utilities import ObjectGround, InertiaCuboid, MarkerBodyRigid, GenericJoint, \ VObjectJointGeneric, SensorBody #to be sure to have all items and functions imported, just do: #from exudyn.utilities import * #includes itemInterface and rigidBodyUtilities import exudyn.graphics as graphics #only import if it does not conflict import numpy as np SC = exu.SystemContainer() mbs = SC.AddSystem() #%%++++++++++++++++++++++++++++++++++++++++++++++++++++ #physical parameters g = [0,-9.81,0] #gravity L = 1 #length w = 0.1 #width bodyDim=[L,w,w] #body dimensions p0 = [0,0,0] #origin of pendulum pMid0 = np.array([L*0.5,0,0]) #center of mass, body0 #ground body oGround = mbs.CreateGround() #%%++++++++++++++++++++++++++++++++++++++++++++++++++++ #first link: #create inertia paramters (mass, center of mass (COM) and inertia tensor at reference point) iCube0 = InertiaCuboid(density=5000, sideLengths=bodyDim) iCube0 = iCube0.Translated([-0.25*L,0,0]) #transform COM, COM not at reference point! #graphics for body graphicsBody0 = graphics.RigidLink(p0=[-0.5*L,0,0],p1=[0.5*L,0,0], axis0=[0,0,1], axis1=[0,0,0], radius=[0.5*w,0.5*w], thickness = w, width = [1.2*w,1.2*w], color=graphics.color.red) graphicsCOM0 = graphics.Basis(origin=iCube0.com, length=2*w) #create rigid body; we could use other formulation, e.g., by selecting nodeType = exu.NodeType.RotationRotationVector b0=mbs.CreateRigidBody(inertia = iCube0, #includes COM referencePosition = pMid0, gravity = g, graphicsDataList = [graphicsCOM0, graphicsBody0]) #%%++++++++++++++++++++++++++ #revolute joint (free z-axis) #markers for ground and rigid body (not needed for option 3): markerGround = mbs.AddMarker(MarkerBodyRigid(bodyNumber=oGround, localPosition=[0,0,0])) markerBody0J0 = mbs.AddMarker(MarkerBodyRigid(bodyNumber=b0, localPosition=[-0.5*L,0,0])) # revolute joint option 1: mbs.AddObject(GenericJoint(markerNumbers=[markerGround, markerBody0J0], constrainedAxes=[1,1,1,1,1,0], visualization=VObjectJointGeneric(axesRadius=0.2*w, axesLength=1.4*w))) #revolute joint option 2: # mbs.AddObject(ObjectJointRevoluteZ(markerNumbers = [markerGround, markerBody0J0], # rotationMarker0=np.eye(3), # rotationMarker1=np.eye(3), # visualization=VObjectJointRevoluteZ(axisRadius=0.2*w, axisLength=1.4*w) # )) #%%++++++++++++++++++++++++++ #second link: graphicsBody1 = graphics.RigidLink(p0=[0,0,-0.5*L],p1=[0,0,0.5*L], axis0=[1,0,0], axis1=[0,0,0], radius=[0.06,0.05], thickness = 0.1, width = [0.12,0.12], color=graphics.color.lightgreen) iCube1 = InertiaCuboid(density=5000, sideLengths=[0.1,0.1,1]) pMid1 = np.array([L,0,0]) + np.array([0,0,0.5*L]) #center of mass, body1 b1=mbs.CreateRigidBody(inertia = iCube1, referencePosition = pMid1, gravity = g, graphicsDataList = [graphicsBody1]) #revolute joint (free x-axis) # #alternative with GenericJoint: # #markers for rigid body: markerBody0J1 = mbs.AddMarker(MarkerBodyRigid(bodyNumber=b0, localPosition=[ 0.5*L,0,0])) markerBody1J0 = mbs.AddMarker(MarkerBodyRigid(bodyNumber=b1, localPosition=[0,0,-0.5*L])) mbs.AddObject(GenericJoint(markerNumbers=[markerBody0J1, markerBody1J0], constrainedAxes=[1,1,1,0,1,1], visualization=VObjectJointGeneric(axesRadius=0.2*w, axesLength=1.4*w))) #position sensor at tip of body1 sens1=mbs.AddSensor(SensorBody(bodyNumber=b1, localPosition=[0,0,0.5*L], fileName='solution/sensorPos.txt', outputVariableType = exu.OutputVariableType.Position)) #%%++++++++++++++++++++++++++++++++++++++++++++++++++++++ #assemble system before solving mbs.Assemble() if False: mbs.systemData.Info() #show detailed information if False: mbs.DrawSystemGraph(useItemTypes=True) #draw nice graph of system simulationSettings = exu.SimulationSettings() #takes currently set values or default values tEnd = 4 #simulation time h = 1e-3 #step size simulationSettings.timeIntegration.numberOfSteps = int(tEnd/h) simulationSettings.timeIntegration.endTime = tEnd simulationSettings.timeIntegration.verboseMode = 1 #simulationSettings.timeIntegration.simulateInRealtime = True simulationSettings.solutionSettings.solutionWritePeriod = 0.005 #store every 5 ms SC.visualizationSettings.window.renderWindowSize=[1600,1200] SC.visualizationSettings.openGL.multiSampling = 4 SC.visualizationSettings.general.autoFitScene = False SC.visualizationSettings.nodes.drawNodesAsPoint=False SC.visualizationSettings.nodes.showBasis=True # uncomment to start visualization during simulation # exu.StartRenderer() # if 'renderState' in exu.sys: #reload old view # SC.SetRenderState(exu.sys['renderState']) #mbs.WaitForUserToContinue() #stop before simulating mbs.SolveDynamic(simulationSettings = simulationSettings, solverType=exu.DynamicSolverType.TrapezoidalIndex2) # SC.WaitForRenderEngineStopFlag() #stop before closing # exu.StopRenderer() #safely close rendering window! #start post processing mbs.SolutionViewer() if False: #plot sensor sens1, y-component [1] mbs.PlotSensor(sensorNumbers=[sens1],components=[1],closeAll=True)