You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
84 lines
3.1 KiB
84 lines
3.1 KiB
import math
|
|
from common.numpy_fast import clip
|
|
|
|
MAX_ANGLE_OFFSET = math.radians(10.)
|
|
MAX_ANGLE_OFFSET_TH = math.radians(9.)
|
|
MIN_STIFFNESS = 0.5
|
|
MAX_STIFFNESS = 2.0
|
|
MIN_SR = 0.5
|
|
MAX_SR = 2.0
|
|
MIN_SR_TH = 0.55
|
|
MAX_SR_TH = 1.9
|
|
|
|
DEBUG = False
|
|
|
|
|
|
class ParamsLearner():
|
|
def __init__(self, VM, angle_offset=0., stiffness_factor=1.0, steer_ratio=None, learning_rate=1.0):
|
|
self.VM = VM
|
|
|
|
self.ao = math.radians(angle_offset)
|
|
self.slow_ao = math.radians(angle_offset)
|
|
self.x = stiffness_factor
|
|
self.sR = VM.sR if steer_ratio is None else steer_ratio
|
|
self.MIN_SR = MIN_SR * self.VM.sR
|
|
self.MAX_SR = MAX_SR * self.VM.sR
|
|
self.MIN_SR_TH = MIN_SR_TH * self.VM.sR
|
|
self.MAX_SR_TH = MAX_SR_TH * self.VM.sR
|
|
|
|
self.alpha1 = 0.01 * learning_rate
|
|
self.alpha2 = 0.0005 * learning_rate
|
|
self.alpha3 = 0.1 * learning_rate
|
|
self.alpha4 = 1.0 * learning_rate
|
|
|
|
def get_values(self):
|
|
return {
|
|
'angleOffsetAverage': math.degrees(self.slow_ao),
|
|
'stiffnessFactor': self.x,
|
|
'steerRatio': self.sR,
|
|
}
|
|
|
|
def update(self, psi, u, sa):
|
|
cF0 = self.VM.cF
|
|
cR0 = self.VM.cR
|
|
aR = self.VM.aR
|
|
aF = self.VM.aF
|
|
l = self.VM.l
|
|
m = self.VM.m
|
|
|
|
x = self.x
|
|
ao = self.ao
|
|
sR = self.sR
|
|
|
|
# Gradient descent: learn angle offset, tire stiffness and steer ratio.
|
|
if u > 10.0 and abs(math.degrees(sa)) < 15.:
|
|
self.ao -= self.alpha1 * 2.0*cF0*cR0*l*u*x*(1.0*cF0*cR0*l*u*x*(ao - sa) + psi*sR*(cF0*cR0*l**2*x - m*u**2*(aF*cF0 - aR*cR0)))/(sR**2*(cF0*cR0*l**2*x - m*u**2*(aF*cF0 - aR*cR0))**2)
|
|
|
|
ao = self.slow_ao
|
|
self.slow_ao -= self.alpha2 * 2.0*cF0*cR0*l*u*x*(1.0*cF0*cR0*l*u*x*(ao - sa) + psi*sR*(cF0*cR0*l**2*x - m*u**2*(aF*cF0 - aR*cR0)))/(sR**2*(cF0*cR0*l**2*x - m*u**2*(aF*cF0 - aR*cR0))**2)
|
|
|
|
self.x -= self.alpha3 * -2.0*cF0*cR0*l*m*u**3*(ao - sa)*(aF*cF0 - aR*cR0)*(1.0*cF0*cR0*l*u*x*(ao - sa) + psi*sR*(cF0*cR0*l**2*x - m*u**2*(aF*cF0 - aR*cR0)))/(sR**2*(cF0*cR0*l**2*x - m*u**2*(aF*cF0 - aR*cR0))**3)
|
|
|
|
self.sR -= self.alpha4 * -2.0*cF0*cR0*l*u*x*(ao - sa)*(1.0*cF0*cR0*l*u*x*(ao - sa) + psi*sR*(cF0*cR0*l**2*x - m*u**2*(aF*cF0 - aR*cR0)))/(sR**3*(cF0*cR0*l**2*x - m*u**2*(aF*cF0 - aR*cR0))**2)
|
|
|
|
if DEBUG:
|
|
# s1 = "Measured yaw rate % .6f" % psi
|
|
# ao = 0.
|
|
# s2 = "Uncompensated yaw % .6f" % (1.0*u*(-ao + sa)/(l*sR*(1 - m*u**2*(aF*cF0*x - aR*cR0*x)/(cF0*cR0*l**2*x**2))))
|
|
# instant_ao = aF*m*psi*sR*u/(cR0*l*x) - aR*m*psi*sR*u/(cF0*l*x) - l*psi*sR/u + sa
|
|
s4 = "Instant AO: % .6f Avg. AO % .6f" % (math.degrees(self.ao), math.degrees(self.slow_ao))
|
|
s5 = "Stiffnes: % .6f x" % self.x
|
|
s6 = "sR: %.4f" % self.sR
|
|
print("{0} {1} {2}".format(s4, s5, s6))
|
|
|
|
|
|
self.ao = clip(self.ao, -MAX_ANGLE_OFFSET, MAX_ANGLE_OFFSET)
|
|
self.slow_ao = clip(self.slow_ao, -MAX_ANGLE_OFFSET, MAX_ANGLE_OFFSET)
|
|
self.x = clip(self.x, MIN_STIFFNESS, MAX_STIFFNESS)
|
|
self.sR = clip(self.sR, self.MIN_SR, self.MAX_SR)
|
|
|
|
# don't check stiffness for validity, as it can change quickly if sR is off
|
|
valid = abs(self.slow_ao) < MAX_ANGLE_OFFSET_TH and \
|
|
self.sR > self.MIN_SR_TH and self.sR < self.MAX_SR_TH
|
|
|
|
return valid
|
|
|