jyoung/selfdrive/controls/lib/lateral_planner.py

import numpy as np
from common.realtime import sec_since_boot, DT_MDL
from common.numpy_fast import interp
from system.swaglog import cloudlog
from selfdrive.controls.lib.lateral_mpc_lib.lat_mpc import LateralMpc
from selfdrive.controls.lib.lateral_mpc_lib.lat_mpc import N as LAT_MPC_N
from selfdrive.controls.lib.drive_helpers import CONTROL_N, MIN_SPEED
from selfdrive.controls.lib.desire_helper import DesireHelper
import cereal.messaging as messaging
from cereal import log

TRAJECTORY_SIZE = 33
CAMERA_OFFSET = 0.04


PATH_COST = 1.0
LATERAL_MOTION_COST = 0.11
LATERAL_ACCEL_COST = 0.0
LATERAL_JERK_COST = 0.04
# Extreme steering rate is unpleasant, even
# when it does not cause bad jerk.
# TODO this cost should be lowered when low
# speed lateral control is stable on all cars
STEERING_RATE_COST = 700.0


class LateralPlanner:
  def __init__(self, CP):
    self.DH = DesireHelper()

    # Vehicle model parameters used to calculate lateral movement of car
    self.factor1 = CP.wheelbase - CP.centerToFront
    self.factor2 = (CP.centerToFront * CP.mass) / (CP.wheelbase * CP.tireStiffnessRear)
    self.last_cloudlog_t = 0
    self.solution_invalid_cnt = 0

    self.path_xyz = np.zeros((TRAJECTORY_SIZE, 3))
    self.velocity_xyz = np.zeros((TRAJECTORY_SIZE, 3))
    self.plan_yaw = np.zeros((TRAJECTORY_SIZE,))
    self.plan_yaw_rate = np.zeros((TRAJECTORY_SIZE,))
    self.t_idxs = np.arange(TRAJECTORY_SIZE)
    self.y_pts = np.zeros(TRAJECTORY_SIZE)

    self.lat_mpc = LateralMpc()
    self.reset_mpc(np.zeros(4))

  def reset_mpc(self, x0=np.zeros(4)):
    self.x0 = x0
    self.lat_mpc.reset(x0=self.x0)

  def update(self, sm):
    # clip speed , lateral planning is not possible at 0 speed
    measured_curvature = sm['controlsState'].curvature

    # Parse model predictions
    md = sm['modelV2']
    if len(md.position.x) == TRAJECTORY_SIZE and len(md.orientation.x) == TRAJECTORY_SIZE:
      self.path_xyz = np.column_stack([md.position.x, md.position.y, md.position.z])
      self.t_idxs = np.array(md.position.t)
      self.plan_yaw = np.array(md.orientation.z)
      self.plan_yaw_rate = np.array(md.orientationRate.z)
      self.velocity_xyz = np.column_stack([md.velocity.x, md.velocity.y, md.velocity.z])
      car_speed = np.linalg.norm(self.velocity_xyz, axis=1)
      self.v_plan = np.clip(car_speed, MIN_SPEED, np.inf)
      self.v_ego = self.v_plan[0]

    # Lane change logic
    desire_state = md.meta.desireState
    if len(desire_state):
      self.l_lane_change_prob = desire_state[log.LateralPlan.Desire.laneChangeLeft]
      self.r_lane_change_prob = desire_state[log.LateralPlan.Desire.laneChangeRight]
    lane_change_prob = self.l_lane_change_prob + self.r_lane_change_prob
    self.DH.update(sm['carState'], sm['carControl'].latActive, lane_change_prob)

    self.lat_mpc.set_weights(PATH_COST, LATERAL_MOTION_COST,
                             LATERAL_ACCEL_COST, LATERAL_JERK_COST,
                             STEERING_RATE_COST)

    y_pts = self.path_xyz[:LAT_MPC_N+1, 1]
    heading_pts = self.plan_yaw[:LAT_MPC_N+1]
    yaw_rate_pts = self.plan_yaw_rate[:LAT_MPC_N+1]
    self.y_pts = y_pts

    assert len(y_pts) == LAT_MPC_N + 1
    assert len(heading_pts) == LAT_MPC_N + 1
    assert len(yaw_rate_pts) == LAT_MPC_N + 1
    lateral_factor = np.clip(self.factor1 - (self.factor2 * self.v_plan**2), 0.0, np.inf)
    p = np.column_stack([self.v_plan, lateral_factor])
    self.lat_mpc.run(self.x0,
                     p,
                     y_pts,
                     heading_pts,
                     yaw_rate_pts)
    # init state for next iteration
    # mpc.u_sol is the desired second derivative of psi given x0 curv state.
    # with x0[3] = measured_yaw_rate, this would be the actual desired yaw rate.
    # instead, interpolate x_sol so that x0[3] is the desired yaw rate for lat_control.
    self.x0[3] = interp(DT_MDL, self.t_idxs[:LAT_MPC_N + 1], self.lat_mpc.x_sol[:, 3])

    #  Check for infeasible MPC solution
    mpc_nans = np.isnan(self.lat_mpc.x_sol[:, 3]).any()
    t = sec_since_boot()
    if mpc_nans or self.lat_mpc.solution_status != 0:
      self.reset_mpc()
      self.x0[3] = measured_curvature * self.v_ego
      if t > self.last_cloudlog_t + 5.0:
        self.last_cloudlog_t = t
        cloudlog.warning("Lateral mpc - nan: True")

    if self.lat_mpc.cost > 20000. or mpc_nans:
      self.solution_invalid_cnt += 1
    else:
      self.solution_invalid_cnt = 0

  def publish(self, sm, pm):
    plan_solution_valid = self.solution_invalid_cnt < 2
    plan_send = messaging.new_message('lateralPlan')
    plan_send.valid = sm.all_checks(service_list=['carState', 'controlsState', 'modelV2'])

    lateralPlan = plan_send.lateralPlan
    lateralPlan.modelMonoTime = sm.logMonoTime['modelV2']
    lateralPlan.dPathPoints = self.y_pts.tolist()
    lateralPlan.psis = self.lat_mpc.x_sol[0:CONTROL_N, 2].tolist()

    lateralPlan.curvatures = (self.lat_mpc.x_sol[0:CONTROL_N, 3]/self.v_ego).tolist()
    lateralPlan.curvatureRates = [float(x/self.v_ego) for x in self.lat_mpc.u_sol[0:CONTROL_N - 1]] + [0.0]

    lateralPlan.mpcSolutionValid = bool(plan_solution_valid)
    lateralPlan.solverExecutionTime = self.lat_mpc.solve_time

    lateralPlan.desire = self.DH.desire
    lateralPlan.useLaneLines = False
    lateralPlan.laneChangeState = self.DH.lane_change_state
    lateralPlan.laneChangeDirection = self.DH.lane_change_direction

    pm.send('lateralPlan', plan_send)