kinematicTreePendulum.py

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  1#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
  2# This is an EXUDYN python utility library
  3#
  4# Details:  test of MarkerKinematicTreeRigid in combination with loads and joint
  5#
  6# Author:   Johannes Gerstmayr
  7# Date:     2022-05-29
  8#
  9# 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.
 10#
 11#+++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 12
 13import exudyn as exu
 14from exudyn.utilities import *
 15from exudyn.FEM import *
 16
 17import numpy as np
 18
 19from math import pi, sin, cos#, sqrt
 20from copy import copy, deepcopy
 21from exudyn.robotics import *
 22
 23SC = exu.SystemContainer()
 24mbs = SC.AddSystem()
 25
 26useGraphics = True
 27
 28gGround =  GraphicsDataCheckerBoard(point= [0,0,-2], size = 12)
 29objectGround = mbs.AddObject(ObjectGround(referencePosition = [0,0,0],
 30                                          visualization=VObjectGround(graphicsData=[gGround])))
 31
 32L = 0.5 #length
 33w = 0.1 #width of links
 34
 35gravity3D = [0,-9.81*1,0]
 36graphicsBaseList = [GraphicsDataOrthoCubePoint(size=[L*4, 0.8*w, 0.8*w], color=color4grey)] #rail
 37
 38newRobot = Robot(gravity=gravity3D,
 39              base = RobotBase(visualization=VRobotBase(graphicsData=graphicsBaseList)),
 40              tool = RobotTool(HT=HTtranslate([0,0.5*L,0]), visualization=VRobotTool(graphicsData=[
 41                  GraphicsDataOrthoCubePoint(size=[w, L, w], color=color4orange)])),
 42              referenceConfiguration = []) #referenceConfiguration created with 0s automatically
 43
 44linksList = []
 45
 46nChainLinks = 1 #5
 47for i in range(nChainLinks):
 48    Jlink = InertiaCuboid(density=1000, sideLengths=[w,L,w]) #w.r.t. reference center of mass
 49    Jlink = Jlink.Translated([0,0.5*L,0])
 50    preHT = HT0()
 51    if i > 0:
 52        preHT = HTtranslateY(L)
 53
 54    link = RobotLink(Jlink.Mass(), Jlink.COM(), Jlink.InertiaCOM(),
 55                     jointType='Rz', preHT=preHT,
 56                     #PDcontrol=(pControl*0, dControl*0),
 57                     visualization=VRobotLink(linkColor=color4blue))
 58    newRobot.AddLink(link)
 59    linksList += [copy(link)]
 60
 61#newRobot.referenceConfiguration[0] = 0.5*0
 62# for i in range(nChainLinks):
 63#     newRobot.referenceConfiguration[i+1] = (2*pi/360) * 5
 64newRobot.referenceConfiguration[0] = -(2*pi/360) * 90 #-0.5*pi
 65# newRobot.referenceConfiguration[2] = (2*pi/360) * 12 #-0.5*pi
 66
 67
 68dKT = newRobot.CreateKinematicTree(mbs)
 69oKT = dKT['objectKinematicTree']
 70
 71sCoords=mbs.AddSensor(SensorBody(bodyNumber=oKT, storeInternal=True,
 72                    outputVariableType=exu.OutputVariableType.Coordinates))
 73
 74mbs.Assemble()
 75
 76simulationSettings = exu.SimulationSettings()
 77
 78tEnd = 2000
 79h = 1e-2#*0.01
 80#tEnd = h
 81
 82simulationSettings.timeIntegration.numberOfSteps = int(tEnd/h)
 83simulationSettings.timeIntegration.endTime = tEnd
 84simulationSettings.solutionSettings.writeSolutionToFile=False
 85simulationSettings.solutionSettings.sensorsWritePeriod = 0.05
 86simulationSettings.timeIntegration.verboseMode = 1
 87
 88simulationSettings.timeIntegration.generalizedAlpha.spectralRadius = 0.95 #SHOULD work with 0.9 as well
 89
 90SC.visualizationSettings.general.autoFitScene=False
 91SC.visualizationSettings.window.renderWindowSize = [1600,1200]
 92SC.visualizationSettings.general.drawCoordinateSystem=True
 93SC.visualizationSettings.general.drawWorldBasis=True
 94SC.visualizationSettings.openGL.multiSampling=4
 95SC.visualizationSettings.nodes.showBasis = True
 96SC.visualizationSettings.nodes.basisSize = 0.5
 97
 98if useGraphics:
 99
100    exu.StartRenderer()
101    if 'renderState' in exu.sys: SC.SetRenderState(exu.sys['renderState']) #load last model view
102
103    mbs.WaitForUserToContinue() #press space to continue
104
105
106
107
108mbs.SolveDynamic(simulationSettings, solverType = exu.DynamicSolverType.ExplicitMidpoint)
109mbs.PlotSensor(sensorNumbers=sCoords, components=0, labels='Explicit Midpoint', colorCodeOffset=2, closeAll=True)
110
111mbs.SolveDynamic(simulationSettings, solverType = exu.DynamicSolverType.RK33)
112mbs.PlotSensor(sensorNumbers=sCoords, components=0, labels='Heun', colorCodeOffset=1, newFigure=False)
113
114mbs.SolveDynamic(simulationSettings, solverType = exu.DynamicSolverType.RK44)
115mbs.PlotSensor(sensorNumbers=sCoords, components=0, labels='Runge Kutta 44', newFigure=False)
116
117
118#mbs.SolveDynamic(simulationSettings)
119
120simulationSettings.timeIntegration.numberOfSteps = int(7/h)
121simulationSettings.timeIntegration.endTime = 7
122mbs.SolveDynamic(simulationSettings, solverType = exu.DynamicSolverType.ExplicitEuler)
123mbs.PlotSensor(sensorNumbers=sCoords, components=0, yLabel='pendulum angle', labels=['Explicit Euler'], colorCodeOffset=3, newFigure=False)
124
125if useGraphics:
126    #SC.WaitForRenderEngineStopFlag()
127    exu.StopRenderer() #safely close rendering window!