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implement 'mimic' joint constraint or 'gear' constraint for btMultiBody, add example in pybullet/examples/mimicJointConstraint.py

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Erwin Coumans
2017-06-07 16:22:02 -07:00
parent 60e3887456
commit 46f2f3db4e
7 changed files with 329 additions and 9 deletions
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19
examples/pybullet/examples/mimicJointConstraint.py
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@@ -1,16 +1,19 @@
#mimic joint currently only works for 'maximal coordinate' rigid bodies
#one way to use it would be to attach maximal coordinate rigid bodies to multibody links using
#fixed constraints
#a mimic joint can act as a gear between two joints
#you can control the gear ratio in magnitude and sign (>0 reverses direction)
import pybullet as p
import time
p.connect(p.GUI)
wheelA = p.loadURDF("wheel.urdf",[0,0,0],useMaximalCoordinates=1)
wheelB = p.loadURDF("wheel.urdf",[0,0,1],useMaximalCoordinates=1)
c = p.createConstraint(wheelA,-1,wheelB,-1,jointType=p.JOINT_GEAR,jointAxis =[0,1,0],parentFramePosition=[0,0,0],childFramePosition=[0,0,0])
p.changeConstraint(c,gearRatio=-0.1)
wheelA = p.loadURDF("wheel.urdf",[0,0,0])
wheelB = p.loadURDF("wheel.urdf",[0,0,1])
p.setJointMotorControl2(wheelA,0,p.VELOCITY_CONTROL,targetVelocity=0,force=0)
p.setJointMotorControl2(wheelB,0,p.VELOCITY_CONTROL,targetVelocity=1,force=1)
c = p.createConstraint(wheelA,0,wheelB,0,jointType=p.JOINT_GEAR,jointAxis =[0,1,0],parentFramePosition=[0,0,0],childFramePosition=[0,0,0])
p.changeConstraint(c,gearRatio=-0.1, maxForce=10000)
p.setRealTimeSimulation(1)
while(1):
time.sleep(0.01)
p.removeConstraint(c)
#p.removeConstraint(c)