PyBullet tutorial - Control

Default motor

for revolute and prismatic joint pybullet automatically create motor that tries to hold the joint at its current position

to disabled the motor we changed to Velocity control and force=0 on request joint

Demo:

• load robot urdf
• disabled default motor

robot urdf

import pybullet as p
import pybullet_data
import time
import pathlib

# setup
p.connect(p.GUI)
p.resetSimulation() # type: ignore
p.setGravity(gravX=0, gravY=0, gravZ=-9.8)
p.setAdditionalSearchPath(path=pybullet_data.getDataPath())
plane = p.loadURDF("plane.urdf")

# add current file location and its 'urdf' subfolder to search paths
cwd = pathlib.Path(__file__).parent.resolve()
cwd = cwd.joinpath("urdf")
p.setAdditionalSearchPath(cwd.as_posix())

# load URDF
robot = p.loadURDF("rrbot.urdf", basePosition=[0, 0, 0.5], useFixedBase=True)
p.setJointMotorControl2(robot, 0, p.VELOCITY_CONTROL, force=0)  # free joint
p.resetJointState(robot, 0, 0.2)  # small initial angle so gravity can act

p.setRealTimeSimulation(True)
try:
    while True:
        keys = p.getKeyboardEvents()

        # 27 = ESC
        if 27 in keys and keys[27] & p.KEY_WAS_TRIGGERED:
            print("ESC pressed, exiting...")
            break

        time.sleep(1/240)

finally:
    p.disconnect()

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Position control