add MIT racecar URDF, meshes and racecar.py quick test

examples/pybullet/examples/racecar.py

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+import pybullet as p
+import time
+
+cid = p.connect(p.SHARED_MEMORY)
+if (cid<0):
+	p.connect(p.GUI)
+	
+p.resetSimulation()
+p.setGravity(0,0,-10)
+
+useRealTimeSim = 1
+
+#for video recording (works best on Mac and Linux, not well on Windows)
+#p.startStateLogging(p.STATE_LOGGING_VIDEO_MP4, "racecar.mp4")
+p.setRealTimeSimulation(useRealTimeSim) # either this
+#p.loadURDF("plane.urdf")
+p.loadSDF("stadium.sdf")
+
+car = p.loadURDF("racecar/racecar.urdf")
+for i in range (p.getNumJoints(car)):
+	print (p.getJointInfo(car,i))
+
+wheels = [2,3,5,7]
+steering = [4,6]
+
+targetVelocitySlider = p.addUserDebugParameter("wheelVelocity",-10,10,0)
+maxForceSlider = p.addUserDebugParameter("maxForce",0,10,10)
+steeringSlider = p.addUserDebugParameter("steering",-0.5,0.5,0)
+while (True):
+	maxForce = p.readUserDebugParameter(maxForceSlider)
+	targetVelocity = p.readUserDebugParameter(targetVelocitySlider)
+	steeringAngle = p.readUserDebugParameter(steeringSlider)
+	#print(targetVelocity)
+	
+	for wheel in wheels:
+		p.setJointMotorControl2(car,wheel,p.VELOCITY_CONTROL,targetVelocity=targetVelocity,force=maxForce)
+		
+	for steer in steering:
+		p.setJointMotorControl2(car,steer,p.POSITION_CONTROL,targetPosition=steeringAngle)
+		
+	steering
+	if (useRealTimeSim==0):
+		p.stepSimulation()
+	time.sleep(0.01)