def test_rigid_body_tree_collision_api(self):
# This test creates a simple RBT with two spheres in simple
# collision and verifies collision-detection APIs.
rbt = RigidBodyTree()
world_body = rbt.world()
# Both bodies are unit-diameter spheres
# spaced 0.5m from each other along the x axis.
for k in range(2):
body = RigidBody()
body.set_name("body_{}".format(k))
joint = PrismaticJoint("x", np.eye(4), np.array([1.0, 0., 0.]))
body.add_joint(world_body, joint)
body.set_spatial_inertia(np.eye(6))
rbt.add_rigid_body(body)
sphere_element = shapes.Sphere(0.5)
sphere_collision_element = CollisionElement(
sphere_element, np.eye(4))
sphere_collision_element.set_body(body)
rbt.addCollisionElement(sphere_collision_element, body, "default")
rbt.compile()
self.assertTrue(rbt.initialized())
self.assertEqual(rbt.get_num_positions(), 2)
q0 = np.array([-0.25, 0.25])
kinsol = rbt.doKinematics(q0)
# One point in each region of overlap:
# Sphere one is (), sphere two is []
# p0 ( p2 [ p3 ) p4 ] p5
points = np.array([[-1., -0.6, 0., 0.6, 1.], [0., 0., 0., 0., 0],
[0., 0., 0., 0., 0]])
n_pts = points.shape[1]
phi, normal, x, body_x, body_idx = rbt.collisionDetectFromPoints(
cache=kinsol, points=points, use_margins=False)
# Check phi, but leave the other fields as API checks.
self.assertTrue(
np.allclose(phi, np.array([0.25, -0.15, -0.25, -0.15, 0.25])))
self.assertEqual(phi.shape[0], n_pts)
self.assertEqual(normal.shape, (3, n_pts))
self.assertEqual(x.shape, (3, n_pts))
self.assertEqual(normal.shape, (3, n_pts))
point_pairs = rbt.ComputeMaximumDepthCollisionPoints(
cache=kinsol, use_margins=False, throw_if_missing_gradient=True)
self.assertEqual(len(point_pairs), 1)
pp = point_pairs[0]
self.assertEqual(rbt.FindCollisionElement(pp.idA), pp.elementA)
self.assertEqual(rbt.FindCollisionElement(pp.idB), pp.elementB)
possible_points = [np.array([0.5, 0., 0.]), np.array([-0.5, 0.0, 0.0])]
for pt in [pp.ptA, pp.ptB]:
self.assertTrue(
np.allclose(pt, np.array([0.5, 0., 0.]))
or np.allclose(pt, np.array([-0.5, 0., 0.])))
self.assertTrue(np.allclose(np.abs(pp.normal), np.array([1., 0., 0.])))
self.assertEqual(pp.distance, -0.5)
def test_rigid_body_tree_programmatic_construction(self):
# Tests RBT programmatic construction methods by assembling
# a simple RBT with a prismatic and revolute joint, with
# both visual and collision geometry on the last joint.
rbt = RigidBodyTree()
world_body = rbt.world()
# body_1 is connected to the world via a prismatic joint along
# the +z axis.
body_1 = RigidBody()
body_1.set_name("body_1")
body_1_joint = PrismaticJoint("z", np.eye(4),
np.array([0., 0., 1.]))
body_1.add_joint(world_body, body_1_joint)
rbt.add_rigid_body(body_1)
# body_2 is connected to body_1 via a revolute joint around the z-axis.
body_2 = RigidBody()
body_2.set_name("body_2")
body_2_joint = RevoluteJoint("theta", np.eye(4),
np.array([0., 0., 1.]))
body_2.add_joint(body_1, body_2_joint)
box_element = shapes.Box([1.0, 1.0, 1.0])
box_visual_element = shapes.VisualElement(
box_element, np.eye(4), [1., 0., 0., 1.])
body_2.AddVisualElement(box_visual_element)
body_2_visual_elements = body_2.get_visual_elements()
rbt.add_rigid_body(body_2)
box_collision_element = CollisionElement(box_element, np.eye(4))
box_collision_element.set_body(body_2)
rbt.addCollisionElement(box_collision_element, body_2, "default")
# Define a collision filter group containing bodies 1 and 2 and make
# that group ignore itself.
rbt.DefineCollisionFilterGroup(name="test_group")
rbt.AddCollisionFilterGroupMember(
group_name="test_group", body_name="body_1", model_id=0)
rbt.AddCollisionFilterGroupMember(
group_name="test_group", body_name="body_2", model_id=0)
rbt.AddCollisionFilterIgnoreTarget("test_group", "test_group")
self.assertFalse(rbt.initialized())
rbt.compile()
self.assertTrue(rbt.initialized())
# The RBT's position vector should now be [z, theta].
self.assertEqual(body_1.get_position_start_index(), 0)
self.assertEqual(body_2.get_position_start_index(), 1)
self.assertIsNotNone(
rbt.FindCollisionElement(
body_2.get_collision_element_ids()[0]))
