#tracking.py
THRESHOLD = (0,100) # Grayscale threshold for dark things...
import sensor, image, time
from pyb import LED
import car
from pid import PID
rho_pid = PID(p=0.4, i=0)
theta_pid = PID(p=0.001, i=0)

BINARY_VISIBLE = True # 首先执行二进制操作，以便您可以看到正在运行的线性回归...虽然可能会降低FPS。

import sensor, image, time

sensor.reset()
sensor.set_pixformat(sensor.GRAYSCALE)
sensor.set_framesize(sensor.QQVGA)
sensor.skip_frames(time = 2000)
clock = time.clock()
# to process a frame sometimes.

while(True):
clock.tick()
img = sensor.snapshot().binary([THRESHOLD])
line = img.get_regression([(255,255) if BINARY_VISIBLE else THRESHOLD])
if (line):
rho_err = abs(line.rho())-img.width()/2
if line.theta()>90:
theta_err = line.theta()-180
else:
theta_err = line.theta()
img.draw_line(line.line(), color = 127)
print(rho_err,line.magnitude(),rho_err)
if line.magnitude()>0:
#if -40<b_err<40 and -30<t_err<30:
rho_output = rho_pid.get_pid(rho_err,1)
theta_output = theta_pid.get_pid(theta_err,1)
output = rho_output+theta_output
car.run(50+output, 50-output)
else:
car.run(0,0)
else:
car.run(50,-50)
pass
#print(clock.fps())

#pid.py
from pyb import millis
from math import pi, isnan

class PID:
_kp = _ki = _kd = _integrator = _imax = 0
_last_error = _last_derivative = _last_t = 0
_RC = 1/(2 * pi * 20)
def init(self, p=0, i=0, d=0, imax=0):
self._kp = float(p)
self._ki = float(i)
self._kd = float(d)
self._imax = abs(imax)
self._last_derivative = float('nan')

def get_pid(self, error, scaler):
    tnow = millis()
    dt = tnow - self._last_t
    output = 0
    if self._last_t == 0 or dt > 1000:
        dt = 0
        self.reset_I()
    self._last_t = tnow
    delta_time = float(dt) / float(1000)
    output += error * self._kp
    if abs(self._kd) > 0 and dt > 0:
        if isnan(self._last_derivative):
            derivative = 0
            self._last_derivative = 0
        else:
            derivative = (error - self._last_error) / delta_time
        derivative = self._last_derivative + \
                                 ((delta_time / (self._RC + delta_time)) * \
                                    (derivative - self._last_derivative))
        self._last_error = error
        self._last_derivative = derivative
        output += self._kd * derivative
    output *= scaler
    if abs(self._ki) > 0 and dt > 0:
        self._integrator += (error * self._ki) * scaler * delta_time
        if self._integrator < -self._imax: self._integrator = -self._imax
        elif self._integrator > self._imax: self._integrator = self._imax
        output += self._integrator
    return output
def reset_I(self):
    self._integrator = 0
    self._last_derivative = float('nan')

#car.py
from pyb import Pin, Timer
inverse_left=False #change it to True to inverse left wheel
inverse_right=False #change it to True to inverse right wheel

ain1 = Pin('P0', Pin.OUT_PP)
ain2 = Pin('P1', Pin.OUT_PP)
bin1 = Pin('P2', Pin.OUT_PP)
bin2 = Pin('P3', Pin.OUT_PP)
ain1.low()
ain2.low()
bin1.low()
bin2.low()

pwma = Pin('P7')
pwmb = Pin('P8')
tim = Timer(4, freq=1000)
ch1 = tim.channel(1, Timer.PWM, pin=pwma)
ch2 = tim.channel(2, Timer.PWM, pin=pwmb)
ch1.pulse_width_percent(0)
ch2.pulse_width_percent(0)

def run(left_speed, right_speed):
if inverse_left==True:
left_speed=(-left_speed)
if inverse_right==True:
right_speed=(-right_speed)

if left_speed < 0:
    ain1.low()
    ain2.high()
else:
    ain1.high()
    ain2.low()
ch1.pulse_width_percent(abs(left_speed))

if right_speed < 0:
    bin1.low()
    bin2.high()
else:
    bin1.high()
    bin2.low()
ch2.pulse_width_percent(abs(right_speed))