Cannot moving AR model......

[allanjjj]

I would like to animate AR model by keyboard input after the model is shown by detecting marker. The model is shown correctly in the center of marker but it cannot move. It just sticks on the marker no matter what key I pressed. Here is the code:

import viz
import vizact
viz.go()

ar = viz.add('artoolkit.dle')
camera = ar.addWebCamera()
marker = camera.addMarker('ar/patt.worldviz',width=1000)
wheel = viz.add('wheelbarrow.ive')
viz.link(marker,wheel)

moveForward = vizact.move(0,0,2,1)
moveBack = vizact.move(0,0,-2,1)
turnRight = vizact.spin(0,1,0,90,1)
turnLeft = vizact.spin(0,1,0,-90,1)

def mykeyboard(whichKey):
if whichKey == viz.KEY_UP:
wheel.addAction(moveForward)
elif whichKey == viz.KEY_DOWN:
wheel.addAction(moveBack)
elif whichKey == viz.KEY_LEFT:
wheel.addAction(turnLeft)
elif whichKey == viz.KEY_RIGHT:
wheel.addAction(turnRight)

viz.callback(viz.KEYDOWN_EVENT, mykeyboard)


Can anyone help me out? many thanks~