Python scriptingΒΆ

In the previous tutorials, we have defined our simulation project in xml. But, you can use python script to configure the simulation as well.

Below is the example script:

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import hrpsys
import hrpsysext
import commands

openhrp_dir = commands.getoutput("pkg-config --variable=prefix openhrp3.1")
model_dir="file://"+openhrp_dir+"/share/OpenHRP-3.1/sample/model/"

sim = hrpsysext.Simulator()
sim.initViewer()
box  = sim.loadBody("box",  model_dir+"box.wrl")
box.rootLink().R = [0,0,0]
box2 = sim.loadBody("box2", model_dir+"box2.wrl")
sim.addCollisionCheckPair(box, box2)
sim.initialize()
sim.simulate(1.0)

This script will:

  • Import hrpsys and hrpsysext libraries (line 1-2)
  • Invoke pkg-config command as a child process to get OpenHRP sample folder (line 5-6)
  • Load the simulator (line 8-9)
  • Load two box models and set its locations (line 10-12)
  • Set collision between the boxes (line 13)
  • Initialize and run the simulation for one second time period (line 14-15)

You can also construct whole the simulation world only by python script:

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import hrpsys
import hrpsysext

sim = hrpsysext.Simulator()
sim.initViewer()

body = sim.createBody("body")

root = body.rootLink()
s1 = root.addCube(0.2, 1.0, 0.2)
s1.diffuse = [1,0,0,1]

child = root.addChildLink("child")
child.b = [0,0.5,0]
child.jointType = "rotate"
child.a = [1,0,0]
child.m = 1.0
child.c = [0,0.5,0]
child.I = [1,0,0,0,1,0,0,0,1]
s2 = child.addCube(0.5, 1.0, 0.1)
s2.b = [0,0.5,0]
s2.diffuse = [0,1,0,1]

sim.initialize()
sim.simulate(3)

This script will:

  • Import hrpsys and hrpsysext libraries (line 1-2)
  • Load the simulator (line 4-5)
  • Create the body model by using cube primitive and color it as red (line 7-11)
  • Create rotation joint and set each physical properties (line 13-19)
  • Create second cube connected to the joint (line 20-22)
  • Initialize and run the simulation for three seconds time period (line 24-25)