Can end-effectors track a pre-defined (e.g. sinusoidal) trajectory?

[stephane-caron]

For starters, you can set the position or orientation of your end-effectors directly using the corresponding functions. Assuming for instance that you configured a left hand task in your current stance, stance.left_hand.set_pos([0.0, 0.5, 0.8]) sets the position of the left hand manipulator in the world frame. From there, you can track a pre-defined trajectory by writing a small process that sets the end effector position at each simulation tick:

class LeftHandSineTrajectory(pymanoid.Process):

    def __init__(self, left_hand):
        super(LeftHandSineTrajectory, self).__init__()  # mandatory for any process
        self.init_y = left_hand.y
        self.left_hand = left_hand
        self.time = 0

    def on_tick(self, sim):
        self.time += sim.dt
        self.left_hand.set_y(self.init_y + 0.1 * numpy.sin(self.time))

You can start or stop trajectory tracking by scheduling the corresponding process:

sine = LeftHandSineTrajectory(stance.left_hand)
sim.schedule(sine)  # start tracking
sim.start()  # if not started yet
sim.unschedule(sine)  # stop tracking