def setup_ik_from_tasks():
"""
Setup the inverse kinematics task by task.
Note
-----
This function is equivalent to :func:`setup_ik_from_stance` above.
Beginners should take a look at that one first.
Notes
-----
See this `tutorial on inverse kinematics
<https://scaron.info/teaching/inverse-kinematics.html>`_ for details.
"""
from pymanoid.tasks import COMTask, ContactTask, DOFTask, PostureTask
# Prepare targets
lf_target = Contact(robot.sole_shape, pos=[0, 0.3, 0])
rf_target = Contact(robot.sole_shape, pos=[0, -0.3, 0])
# Initial robot pose
robot.set_dof_values([0.8], dof_indices=[robot.TRANS_Z])
com = PointMass(pos=robot.com, mass=robot.mass)
# Prepare tasks
left_foot_task = ContactTask(robot,
robot.left_foot,
lf_target,
weight=1.,
gain=0.85)
right_foot_task = ContactTask(robot,
robot.right_foot,
rf_target,
weight=1.,
gain=0.85)
com_task = COMTask(robot, com, weight=1e-2, gain=0.85)
posture_task = PostureTask(robot, robot.q_halfsit, weight=1e-6, gain=0.85)
# Add tasks to the IK solver
robot.ik.add(left_foot_task)
robot.ik.add(right_foot_task)
robot.ik.add(com_task)
robot.ik.add(posture_task)
# Add shoulder DOF tasks for a nicer posture
robot.ik.add(
DOFTask(robot, robot.R_SHOULDER_R, -0.5, gain=0.5, weight=1e-5))
robot.ik.add(
DOFTask(robot, robot.L_SHOULDER_R, +0.5, gain=0.5, weight=1e-5))
q_init[dof_id] = dof_ref
robot.set_dof_values([-1], [robot.R_SHOULDER_P])
robot.set_dof_values([-1], [robot.L_SHOULDER_P])
robot.set_dof_values([0.8], dof_indices=[robot.TRANS_Z])
init_com = robot.com.copy()
# IK targets
com = Cube(0.05, pos=robot.com, color='g')
lf_target = Contact(robot.sole_shape, pos=[0, 0.3, 0], visible=True)
rf_target = Contact(robot.sole_shape, pos=[0, -0.3, 0], visible=True)
# IK tasks
lf_task = ContactTask(robot, robot.left_foot, lf_target, weight=1000)
rf_task = ContactTask(robot, robot.right_foot, rf_target, weight=1000)
com_task = COMTask(robot, com, weight=10)
reg_task = PostureTask(robot, robot.q, weight=0.1) # regularization task
# IK setup
robot.init_ik(active_dofs=robot.whole_body)
robot.ik.add_tasks([lf_task, rf_task, com_task, reg_task])
for (dof_id, dof_ref) in dof_targets:
robot.ik.add_task(
DOFTask(robot, dof_id, dof_ref, gain=0.5, weight=0.1))
# First, generate an initial posture
robot.solve_ik(max_it=100, conv_tol=1e-4, debug=True)
# Next, we move the COM back and forth for 10 seconds
move_com_back_and_forth(10)
# Finally, we start the simulation with the IK on
robot.set_dof_values([0.8], dof_indices=[robot.TRANS_Z])
com = PointMass(pos=robot.com, mass=robot.mass)
# IK tasks
lf_task = ContactTask(robot,
robot.left_foot,
lf_target,
weight=1.,
gain=0.85)
rf_task = ContactTask(robot,
robot.right_foot,
rf_target,
weight=1.,
gain=0.85)
com_task = COMTask(robot, com, weight=1e-2, gain=0.85)
reg_task = PostureTask(robot, robot.q, weight=1e-6, gain=0.85)
# IK setup
robot.ik.clear_tasks()
robot.ik.add_task(lf_task)
robot.ik.add_task(rf_task)
robot.ik.add_task(com_task)
robot.ik.add_task(reg_task)
# Add some DOFTasks for a nicer posture
robot.ik.add_task(
DOFTask(robot, robot.R_SHOULDER_R, -0.5, gain=0.5, weight=1e-5))
robot.ik.add_task(
DOFTask(robot, robot.L_SHOULDER_R, +0.5, gain=0.5, weight=1e-5))
# First, generate an initial posture