cliport/tasks/primitives.py

"""Motion primitives."""

import numpy as np
from cliport.utils import utils


class PickPlace():
    """Pick and place primitive."""

    def __init__(self, height=0.32, speed=0.01):
        self.height, self.speed = height, speed

    def __call__(self, movej, movep, ee, pose0, pose1):
        """Execute pick and place primitive.
    
        Args:
          movej: function to move robot joints.
          movep: function to move robot end effector pose.
          ee: robot end effector.
          pose0: SE(3) picking pose.
          pose1: SE(3) placing pose.
    
        Returns:
          timeout: robot movement timed out if True.
        """

        pick_pose, place_pose = pose0, pose1

        # Execute picking primitive.
        prepick_to_pick = ((0, 0, 0.32), (0, 0, 0, 1))
        postpick_to_pick = ((0, 0, self.height), (0, 0, 0, 1))
        prepick_pose = utils.multiply(pick_pose, prepick_to_pick)
        postpick_pose = utils.multiply(pick_pose, postpick_to_pick)
        timeout = movep(prepick_pose)

        # Move towards pick pose until contact is detected.
        delta = (np.float32([0, 0, -0.001]),
                 utils.eulerXYZ_to_quatXYZW((0, 0, 0)))
        targ_pose = prepick_pose
        while not ee.detect_contact():  # and target_pose[2] > 0:
            targ_pose = utils.multiply(targ_pose, delta)
            timeout |= movep(targ_pose)
            if timeout:
                return True

        # Activate end effector, move up, and check picking success.
        ee.activate()
        timeout |= movep(postpick_pose, self.speed)
        pick_success = ee.check_grasp()

        # Execute placing primitive if pick is successful.
        if pick_success:
            preplace_to_place = ((0, 0, self.height), (0, 0, 0, 1))
            postplace_to_place = ((0, 0, 0.32), (0, 0, 0, 1))
            preplace_pose = utils.multiply(place_pose, preplace_to_place)
            postplace_pose = utils.multiply(place_pose, postplace_to_place)
            targ_pose = preplace_pose
            while not ee.detect_contact():
                targ_pose = utils.multiply(targ_pose, delta)
                timeout |= movep(targ_pose, self.speed)
                if timeout:
                    return True
            ee.release()
            timeout |= movep(postplace_pose)

        # Move to prepick pose if pick is not successful.
        else:
            ee.release()
            timeout |= movep(prepick_pose)

        return timeout


def push(movej, movep, ee, pose0, pose1):  # pylint: disable=unused-argument
    """Execute pushing primitive.
  
    Args:
      movej: function to move robot joints.
      movep: function to move robot end effector pose.
      ee: robot end effector.
      pose0: SE(3) starting pose.
      pose1: SE(3) ending pose.
  
    Returns:
      timeout: robot movement timed out if True.
    """

    # Adjust push start and end positions.
    pos0 = np.float32((pose0[0][0], pose0[0][1], 0.005))
    pos1 = np.float32((pose1[0][0], pose1[0][1], 0.005))
    vec = np.float32(pos1) - np.float32(pos0)
    length = np.linalg.norm(vec)
    vec = vec / length
    pos0 -= vec * 0.02
    pos1 -= vec * 0.05

    # Align spatula against push direction.
    theta = np.arctan2(vec[1], vec[0])
    rot = utils.eulerXYZ_to_quatXYZW((0, 0, theta))

    over0 = (pos0[0], pos0[1], 0.31)
    over1 = (pos1[0], pos1[1], 0.31)

    # Execute push.
    timeout = movep((over0, rot))
    timeout |= movep((pos0, rot))
    n_push = np.int32(np.floor(np.linalg.norm(pos1 - pos0) / 0.01))
    for _ in range(n_push):
        target = pos0 + vec * n_push * 0.01
        timeout |= movep((target, rot), speed=0.003)
    timeout |= movep((pos1, rot), speed=0.003)
    timeout |= movep((over1, rot))
    return timeout