Treadmill/converyor belt surface/contact velocity example in python

[rohit-kumar-j]

Is there a better way to impart contact/surface velocity(treadmill-like?) as compared to the below-mentioned?

desired behavior:

bullet_treadmill.mp4

import pybullet as p
import pybullet_data
import time

client = p.connect(p.GUI)
p.setAdditionalSearchPath(pybullet_data.getDataPath())

tile_1_pos = [0,0,0]
tile_1_orn = [ 0, -0.0008727, 0, 0.9999996]
tile_2_pos = [2,0,-0.001]
tile_2_orn = [0.005, 0, 0, 0.9999875]
tile_3_pos = [2,2,-0.002]
tile_3_orn = [0, 0.0000873, 0, 1]
tile_4_pos = [0,2,-0.002]
tile_4_orn = [-0.0000873, 0, 0, 1]

tile_1 = p.loadURDF("plane.urdf",useFixedBase=True,globalScaling=0.01,basePosition=tile_1_pos,baseOrientation=tile_1_orn)
tile_2 = p.loadURDF("plane.urdf",useFixedBase=True,globalScaling=0.01,basePosition=tile_2_pos,baseOrientation=tile_2_orn)
tile_3 = p.loadURDF("plane.urdf",useFixedBase=True,globalScaling=0.01,basePosition=tile_3_pos,baseOrientation=tile_3_orn)
tile_4 = p.loadURDF("plane.urdf",useFixedBase=True,globalScaling=0.01,basePosition=tile_4_pos,baseOrientation=tile_4_orn)
block_1 = p.loadURDF("block.urdf",useFixedBase=True,globalScaling=40,basePosition=[1,-1,0])
block_2 = p.loadURDF("block.urdf",useFixedBase=True,globalScaling=40,basePosition=[3,1,0],baseOrientation=[0, 0, 0.7071068, 0.7071068])
block_3 = p.loadURDF("block.urdf",useFixedBase=True,globalScaling=40,basePosition=[-1,1,0],baseOrientation=[0, 0, 0.7071068, 0.7071068])
block_4 = p.loadURDF("block.urdf",useFixedBase=True,globalScaling=40,basePosition=[1,3,0])

ball = p.loadURDF("sphere_small.urdf",basePosition=[0,0,0.2],globalScaling=5.0)
cube = p.loadURDF("cube_small.urdf",basePosition=[1,0,0.2],globalScaling=5.0)
p.setGravity(0,0,-9.81)
speed = 2.0
while 1:
    ball_old_pos,ball_old_orn = p.getBasePositionAndOrientation(bodyUniqueId=ball)
    cube_old_pos,cube_old_orn = p.getBasePositionAndOrientation(bodyUniqueId=cube)
    p.stepSimulation()
    time.sleep(1./240.)
    p.resetBasePositionAndOrientation(bodyUniqueId=tile_1,posObj=tile_1_pos,ornObj=tile_1_orn)
    p.resetBasePositionAndOrientation(bodyUniqueId=tile_2,posObj=tile_2_pos,ornObj=tile_2_orn)
    p.resetBasePositionAndOrientation(bodyUniqueId=tile_3,posObj=tile_3_pos,ornObj=tile_3_orn)
    p.resetBasePositionAndOrientation(bodyUniqueId=tile_4,posObj=tile_4_pos,ornObj=tile_4_orn)
    p.resetBaseVelocity(objectUniqueId=tile_1,linearVelocity=[speed,-speed,0])
    p.resetBaseVelocity(objectUniqueId=tile_2,linearVelocity=[speed,speed,0])
    p.resetBaseVelocity(objectUniqueId=tile_3,linearVelocity=[-speed,speed,0])
    p.resetBaseVelocity(objectUniqueId=tile_4,linearVelocity=[-speed,-speed,0])
    ball_new_pos,ball_new_orn = p.getBasePositionAndOrientation(bodyUniqueId=ball)
    cube_new_pos,cube_new_orn = p.getBasePositionAndOrientation(bodyUniqueId=cube)
    p.addUserDebugLine(lineFromXYZ=ball_old_pos,lineToXYZ=ball_new_pos,lifeTime=0.0,lineWidth=1.0,lineColorRGB=[0,0,0])
    p.addUserDebugLine(lineFromXYZ=cube_old_pos,lineToXYZ=cube_new_pos,lifeTime=0.0,lineWidth=1.0,lineColorRGB=[1,1,1])
p.disconnect()

Problem: The surface twitches super fast and when the ball is pulled into the ground, it behaves as follows...

bullet_treadmill_problem.mp4