dragonpilot - 基於 openpilot 的開源駕駛輔助系統
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#!/usr/bin/env python3
import sys
import numpy as np
import sympy as sp
from selfdrive.locationd.models.constants import ObservationKind
from rednose.helpers.ekf_sym import gen_code, EKF_sym
class LaneKalman():
name = 'lane'
@staticmethod
def generate_code(generated_dir):
# make functions and jacobians with sympy
# state variables
dim = 6
state = sp.MatrixSymbol('state', dim, 1)
dd = sp.Symbol('dd') # WARNING: NOT TIME
# Time derivative of the state as a function of state
state_dot = sp.Matrix(np.zeros((dim, 1)))
state_dot[:3,0] = sp.Matrix(state[3:6,0])
# Basic descretization, 1st order intergrator
# Can be pretty bad if dt is big
f_sym = sp.Matrix(state) + dd*state_dot
#
# Observation functions
#
h_lane_sym = sp.Matrix(state[:3,0])
obs_eqs = [[h_lane_sym, ObservationKind.LANE_PT, None]]
gen_code(generated_dir, LaneKalman.name, f_sym, dd, state, obs_eqs, dim, dim)
def __init__(self, generated_dir, pt_std=5):
# state
# left and right lane centers in ecef
# WARNING: this is not a temporal model
# the 'time' in this kalman filter is
# the distance traveled by the vehicle,
# which should approximately be the
# distance along the lane path
# a more logical parametrization
# states 0-2 are ecef coordinates distance d
# states 3-5 is the 3d "velocity" of the
# lane in ecef (m/m).
x_initial = np.array([0,0,0,
0,0,0])
# state covariance
P_initial = np.diag([1e16, 1e16, 1e16,
1**2, 1**2, 1**2])
# process noise
Q = np.diag([0.1**2, 0.1**2, 0.1**2,
0.1**2, 0.1**2, 0.1*2])
self.dim_state = len(x_initial)
# init filter
self.filter = EKF_sym(generated_dir, self.name, Q, x_initial, P_initial, x_initial.shape[0], P_initial.shape[0])
self.obs_noise = {ObservationKind.LANE_PT: np.diag([pt_std**2]*3)}
@property
def x(self):
return self.filter.state()
@property
def P(self):
return self.filter.covs()
def predict(self, t):
return self.filter.predict(t)
def rts_smooth(self, estimates):
return self.filter.rts_smooth(estimates, norm_quats=False)
def init_state(self, state, covs_diag=None, covs=None, filter_time=None):
if covs_diag is not None:
P = np.diag(covs_diag)
elif covs is not None:
P = covs
else:
P = self.filter.covs()
self.filter.init_state(state, P, filter_time)
def predict_and_observe(self, t, kind, data):
data = np.atleast_2d(data)
return self.filter.predict_and_update_batch(t, kind, data, self.get_R(kind, len(data)))
def get_R(self, kind, n):
obs_noise = self.obs_noise[kind]
dim = obs_noise.shape[0]
R = np.zeros((n, dim, dim))
for i in range(n):
R[i,:,:] = obs_noise
return R
if __name__ == "__main__":
generated_dir = sys.argv[2]
LaneKalman.generate_code(generated_dir)