tsid_biped.py

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import os
import subprocess
import time
 
import numpy as np
import pinocchio as pin
 
import tsid
 
 
class TsidBiped:
    """Standard TSID formulation for a biped robot standing on its rectangular feet.
    - Center of mass task
    - Postural task
    - 6d rigid contact constraint for both feet
    - Regularization task for contact forces
    """
 
    def __init__(self, conf, viewer=pin.visualize.MeshcatVisualizer):
        self.conf = conf
        self.robot = tsid.RobotWrapper(
            conf.urdf, [conf.path], pin.JointModelFreeFlyer(), False
        )
        robot = self.robot
        self.model = robot.model()
        pin.loadReferenceConfigurations(self.model, conf.srdf, False)
        self.q0 = q = self.model.referenceConfigurations["half_sitting"]
        v = np.zeros(robot.nv)
 
        assert self.model.existFrame(conf.rf_frame_name)
        assert self.model.existFrame(conf.lf_frame_name)
 
        formulation = tsid.InverseDynamicsFormulationAccForce("tsid", robot, False)
        formulation.computeProblemData(0.0, q, v)
        data = formulation.data()
        contact_Point = np.ones((3, 4)) * (-conf.lz)
        contact_Point[0, :] = [-conf.lxn, -conf.lxn, conf.lxp, conf.lxp]
        contact_Point[1, :] = [-conf.lyn, conf.lyp, -conf.lyn, conf.lyp]
 
        contactRF = tsid.Contact6d(
            "contact_rfoot",
            robot,
            conf.rf_frame_name,
            contact_Point,
            conf.contactNormal,
            conf.mu,
            conf.fMin,
            conf.fMax,
        )
        contactRF.setKp(conf.kp_contact * np.ones(6))
        contactRF.setKd(2.0 * np.sqrt(conf.kp_contact) * np.ones(6))
        self.RF = robot.model().getFrameId(conf.rf_frame_name)
        H_rf_ref = robot.framePosition(data, self.RF)
 
        # modify initial robot configuration so that foot is on the ground (z=0)
        q[2] -= H_rf_ref.translation[2] - conf.lz
        formulation.computeProblemData(0.0, q, v)
        data = formulation.data()
        H_rf_ref = robot.framePosition(data, self.RF)
        contactRF.setReference(H_rf_ref)
        if conf.w_contact >= 0.0:
            formulation.addRigidContact(contactRF, conf.w_forceRef, conf.w_contact, 1)
        else:
            formulation.addRigidContact(contactRF, conf.w_forceRef)
 
        contactLF = tsid.Contact6d(
            "contact_lfoot",
            robot,
            conf.lf_frame_name,
            contact_Point,
            conf.contactNormal,
            conf.mu,
            conf.fMin,
            conf.fMax,
        )
        contactLF.setKp(conf.kp_contact * np.ones(6))
        contactLF.setKd(2.0 * np.sqrt(conf.kp_contact) * np.ones(6))
        self.LF = robot.model().getFrameId(conf.lf_frame_name)
        H_lf_ref = robot.framePosition(data, self.LF)
        contactLF.setReference(H_lf_ref)
        if conf.w_contact >= 0.0:
            formulation.addRigidContact(contactLF, conf.w_forceRef, conf.w_contact, 1)
        else:
            formulation.addRigidContact(contactLF, conf.w_forceRef)
 
        comTask = tsid.TaskComEquality("task-com", robot)
        comTask.setKp(conf.kp_com * np.ones(3))
        comTask.setKd(2.0 * np.sqrt(conf.kp_com) * np.ones(3))
        formulation.addMotionTask(comTask, conf.w_com, 1, 0.0)
 
        copTask = tsid.TaskCopEquality("task-cop", robot)
        formulation.addForceTask(copTask, conf.w_cop, 1, 0.0)
 
        amTask = tsid.TaskAMEquality("task-am", robot)
        amTask.setKp(conf.kp_am * np.array([1.0, 1.0, 0.0]))
        amTask.setKd(2.0 * np.sqrt(conf.kp_am * np.array([1.0, 1.0, 0.0])))
        formulation.addMotionTask(amTask, conf.w_am, 1, 0.0)
        sampleAM = tsid.TrajectorySample(3)
        amTask.setReference(sampleAM)
 
        postureTask = tsid.TaskJointPosture("task-posture", robot)
        postureTask.setKp(conf.kp_posture * conf.gain_vector)
        postureTask.setKd(2.0 * np.sqrt(conf.kp_posture * conf.gain_vector))
        postureTask.setMask(conf.masks_posture)
        formulation.addMotionTask(postureTask, conf.w_posture, 1, 0.0)
 
        self.leftFootTask = tsid.TaskSE3Equality(
            "task-left-foot", self.robot, self.conf.lf_frame_name
        )
        self.leftFootTask.setKp(self.conf.kp_foot * np.ones(6))
        self.leftFootTask.setKd(2.0 * np.sqrt(self.conf.kp_foot) * np.ones(6))
        self.trajLF = tsid.TrajectorySE3Constant("traj-left-foot", H_lf_ref)
        formulation.addMotionTask(self.leftFootTask, self.conf.w_foot, 1, 0.0)
 
        self.rightFootTask = tsid.TaskSE3Equality(
            "task-right-foot", self.robot, self.conf.rf_frame_name
        )
        self.rightFootTask.setKp(self.conf.kp_foot * np.ones(6))
        self.rightFootTask.setKd(2.0 * np.sqrt(self.conf.kp_foot) * np.ones(6))
        self.trajRF = tsid.TrajectorySE3Constant("traj-right-foot", H_rf_ref)
        formulation.addMotionTask(self.rightFootTask, self.conf.w_foot, 1, 0.0)
 
        self.tau_max = conf.tau_max_scaling * robot.model().effortLimit[-robot.na :]
        self.tau_min = -self.tau_max
        actuationBoundsTask = tsid.TaskActuationBounds("task-actuation-bounds", robot)
        actuationBoundsTask.setBounds(self.tau_min, self.tau_max)
        if conf.w_torque_bounds > 0.0:
            formulation.addActuationTask(
                actuationBoundsTask, conf.w_torque_bounds, 0, 0.0
            )
 
        jointBoundsTask = tsid.TaskJointBounds("task-joint-bounds", robot, conf.dt)
        self.v_max = conf.v_max_scaling * robot.model().velocityLimit[-robot.na :]
        self.v_min = -self.v_max
        jointBoundsTask.setVelocityBounds(self.v_min, self.v_max)
        if conf.w_joint_bounds > 0.0:
            formulation.addMotionTask(jointBoundsTask, conf.w_joint_bounds, 0, 0.0)
 
        com_ref = robot.com(data)
        self.trajCom = tsid.TrajectoryEuclidianConstant("traj_com", com_ref)
        self.sample_com = self.trajCom.computeNext()
 
        q_ref = q[7:]
        self.trajPosture = tsid.TrajectoryEuclidianConstant("traj_joint", q_ref)
        postureTask.setReference(self.trajPosture.computeNext())
 
        self.sampleLF = self.trajLF.computeNext()
        self.sample_LF_pos = self.sampleLF.pos()
        self.sample_LF_vel = self.sampleLF.vel()
        self.sample_LF_acc = self.sampleLF.acc()
 
        self.sampleRF = self.trajRF.computeNext()
        self.sample_RF_pos = self.sampleRF.pos()
        self.sample_RF_vel = self.sampleRF.vel()
        self.sample_RF_acc = self.sampleRF.acc()
 
        self.solver = tsid.SolverHQuadProgFast("qp solver")
        self.solver.resize(formulation.nVar, formulation.nEq, formulation.nIn)
 
        self.comTask = comTask
        self.copTask = copTask
        self.amTask = amTask
        self.postureTask = postureTask
        self.contactRF = contactRF
        self.contactLF = contactLF
        self.actuationBoundsTask = actuationBoundsTask
        self.jointBoundsTask = jointBoundsTask
        self.formulation = formulation
        self.q = q
        self.v = v
 
        self.contact_LF_active = True
        self.contact_RF_active = True
 
        if viewer:
            self.robot_display = pin.RobotWrapper.BuildFromURDF(
                conf.urdf, [conf.path], pin.JointModelFreeFlyer()
            )
            if viewer == pin.visualize.GepettoVisualizer:
                launched = subprocess.getstatusoutput(
                    "ps aux |grep 'gepetto-gui'|grep -v 'grep'|wc -l"
                )
                if int(launched[1]) == 0:
                    os.system("gepetto-gui &")
                time.sleep(1)
                self.viz = viewer(
                    self.robot_display.model,
                    self.robot_display.collision_model,
                    self.robot_display.visual_model,
                )
                self.viz.initViewer(loadModel=True)
                self.viz.displayCollisions(False)
                self.viz.displayVisuals(True)
                self.viz.display(q)
 
                self.gui = self.viz.viewer.gui
                # self.gui.setCameraTransform(0, conf.CAMERA_TRANSFORM)
                self.gui.addFloor("world/floor")
                self.gui.setLightingMode("world/floor", "OFF")
            elif viewer == pin.visualize.MeshcatVisualizer:
                self.viz = viewer(
                    self.robot_display.model,
                    self.robot_display.collision_model,
                    self.robot_display.visual_model,
                )
                self.viz.initViewer(loadModel=True, open=True)
                self.viz.display(q)
 
    def display(self, q):
        if hasattr(self, "viz"):
            self.viz.display(q)
 
    def integrate_dv(self, q, v, dv, dt):
        v_mean = v + 0.5 * dt * dv
        v += dt * dv
        q = pin.integrate(self.model, q, dt * v_mean)
        return q, v
 
    def get_placement_LF(self):
        return self.robot.framePosition(self.formulation.data(), self.LF)
 
    def get_placement_RF(self):
        return self.robot.framePosition(self.formulation.data(), self.RF)
 
    def set_com_ref(self, pos, vel, acc):
        self.sample_com.pos(pos)
        self.sample_com.vel(vel)
        self.sample_com.acc(acc)
        self.comTask.setReference(self.sample_com)
 
    def set_RF_3d_ref(self, pos, vel, acc):
        self.sample_RF_pos[:3] = pos
        self.sample_RF_vel[:3] = vel
        self.sample_RF_acc[:3] = acc
        self.sampleRF.pos(self.sample_RF_pos)
        self.sampleRF.vel(self.sample_RF_vel)
        self.sampleRF.acc(self.sample_RF_acc)
        self.rightFootTask.setReference(self.sampleRF)
 
    def set_LF_3d_ref(self, pos, vel, acc):
        self.sample_LF_pos[:3] = pos
        self.sample_LF_vel[:3] = vel
        self.sample_LF_acc[:3] = acc
        self.sampleLF.pos(self.sample_LF_pos)
        self.sampleLF.vel(self.sample_LF_vel)
        self.sampleLF.acc(self.sample_LF_acc)
        self.leftFootTask.setReference(self.sampleLF)
 
    def get_LF_3d_pos_vel_acc(self, dv):
        data = self.formulation.data()
        H = self.robot.framePosition(data, self.LF)
        v = self.robot.frameVelocity(data, self.LF)
        a = self.leftFootTask.getAcceleration(dv)
        return H.translation, v.linear, a[:3]
 
    def get_RF_3d_pos_vel_acc(self, dv):
        data = self.formulation.data()
        H = self.robot.framePosition(data, self.RF)
        v = self.robot.frameVelocity(data, self.RF)
        a = self.rightFootTask.getAcceleration(dv)
        return H.translation, v.linear, a[:3]
 
    def remove_contact_RF(self, transition_time=0.0):
        H_rf_ref = self.robot.framePosition(self.formulation.data(), self.RF)
        self.trajRF.setReference(H_rf_ref)
        self.rightFootTask.setReference(self.trajRF.computeNext())
 
        self.formulation.removeRigidContact(self.contactRF.name, transition_time)
        self.contact_RF_active = False
 
    def remove_contact_LF(self, transition_time=0.0):
        H_lf_ref = self.robot.framePosition(self.formulation.data(), self.LF)
        self.trajLF.setReference(H_lf_ref)
        self.leftFootTask.setReference(self.trajLF.computeNext())
 
        self.formulation.removeRigidContact(self.contactLF.name, transition_time)
        self.contact_LF_active = False
 
    def add_contact_RF(self, transition_time=0.0):
        H_rf_ref = self.robot.framePosition(self.formulation.data(), self.RF)
        self.contactRF.setReference(H_rf_ref)
        if self.conf.w_contact >= 0.0:
            self.formulation.addRigidContact(
                self.contactRF, self.conf.w_forceRef, self.conf.w_contact, 1
            )
        else:
            self.formulation.addRigidContact(self.contactRF, self.conf.w_forceRef)
 
        self.contact_RF_active = True
 
    def add_contact_LF(self, transition_time=0.0):
        H_lf_ref = self.robot.framePosition(self.formulation.data(), self.LF)
        self.contactLF.setReference(H_lf_ref)
        if self.conf.w_contact >= 0.0:
            self.formulation.addRigidContact(
                self.contactLF, self.conf.w_forceRef, self.conf.w_contact, 1
            )
        else:
            self.formulation.addRigidContact(self.contactLF, self.conf.w_forceRef)
 
        self.contact_LF_active = True