好的，我还想问下，怎样让转向低速转变的和正常一样，改那个h-pid还是该最后的数值，怎样让他不低速

import sensor, image, time
import car
from pid import PID
sensor.reset()
sensor.set_pixformat(sensor.RGB565)
sensor.set_framesize(sensor.QQVGA)
sensor.skip_frames(10)
sensor.set_auto_whitebal(False)
clock = time.clock()
green_threshold   = (14, 83, -128, 86, 20, 62)
size_threshold = 2000
x_pid = PID(p=0.5, i=1, imax=100)
h_pid = PID(p=0.5, i=0.1, imax=50)
def find_max(blobs):
	max_size=0
	for blob in blobs:
		if blob[2]*blob[3] > max_size:
			max_blob=blob
			max_size = blob[2]*blob[3]
	return max_blob
while(True):
	clock.tick()
	img = sensor.snapshot()
	blobs = img.find_blobs([green_threshold])
	if blobs:
		max_blob = find_max(blobs)
		x_error = max_blob[5]-img.width()/2
		h_error = max_blob[2]*max_blob[3]-size_threshold
		print("x error: ", x_error)
		img.draw_rectangle(max_blob[0:4])
		img.draw_cross(max_blob[5], max_blob[6])
		x_output=x_pid.get_pid(x_error,1)
		h_output=h_pid.get_pid(h_error,1)
		print("h_output",h_output)
		car.run(-h_output-x_output,-h_output+x_output)
	else:
		car.run(20,-20)

我用了舵机扩展板，扩展板那个可以

# These pins control our direction while the other PWN pins
# below control the speed. The direction for each motor
# is set by an H-Bridge where A0/1 are the two sides of
# one H-Bridge driver. B0/1 are another H-Bridge.
pinADir0 = pyb.Pin('P3', pyb.Pin.OUT_PP, pyb.Pin.PULL_NONE)
pinADir1 = pyb.Pin('P2', pyb.Pin.OUT_PP, pyb.Pin.PULL_NONE)
pinBDir0 = pyb.Pin('P1', pyb.Pin.OUT_PP, pyb.Pin.PULL_NONE)
pinBDir1 = pyb.Pin('P0', pyb.Pin.OUT_PP, pyb.Pin.PULL_NONE)

# Dir0/1 must be not equal to each other for forward or backwards
# operation. If they are equal then that's a brake operation.
# If they are not equal then the motor will spin one way other the
# other depending on it's hookup and the value of dir 0.
pinADir0.value(0)
pinADir1.value(1)

# Dir0/1 must be not equal to each other for forward or backwards
# operation. If they are equal then that's a brake operation.
# If they are not equal then the motor will spin one way other the
# other depending on it's hookup and the value of dir 0.
pinBDir0.value(0)
pinBDir1.value(1)

# Create a timer object running at 1KHz which which will power the
# PWM output on our OpenMV Cam. Just needs to be created once.
tim = pyb.Timer(4, freq=1000)

# Use the timer object to create two PWM outputs on the OpenMV Cam.
# These timers control the speed of the motors. You will be setting
# the PWM percentage of these timers repeatedly in your loop.
chA = tim.channel(1, pyb.Timer.PWM, pin=pyb.Pin("P7"))
chB = tim.channel(2, pyb.Timer.PWM, pin=pyb.Pin("P8"))
import sensor, image, time

from pid import PID
from pyb import Servo

pan_servo=Servo(1)

pan_servo.calibration(500,2500,500)

red_threshold  = (20, 60, 78, -127, 57, 8)

pan_pid = PID(p=0.07, i=0, imax=90) #脱机运行或者禁用图像传输，使用这个PID
#pan_pid = PID(p=0.1, i=0, imax=90)#在线调试使用这个PID

sensor.reset() # Initialize the camera sensor.
sensor.set_pixformat(sensor.RGB565) # use RGB565.
sensor.set_framesize(sensor.QQVGA) # use QQVGA for speed.
sensor.skip_frames(10) # Let new settings take affect.
sensor.set_auto_whitebal(False) # turn this off.
clock = time.clock() # Tracks FPS.

def find_max(blobs):
    max_size=0
    for blob in blobs:
        if blob[2]*blob[3] > max_size:
            max_blob=blob
            max_size = blob[2]*blob[3]
    return max_blob
while (True):
    chA.pulse_width_percent(80)
    chB.pulse_width_percent(80)
    clock.tick() # Track elapsed milliseconds between snapshots().
    img = sensor.snapshot() # Take a picture and return the image.

    blobs = img.find_blobs([red_threshold])
    if blobs:
        max_blob = find_max(blobs)
        pan_error = max_blob.cx()-img.width()/2

        print("pan_error: ", pan_error)

        img.draw_rectangle(max_blob.rect()) # rect
        img.draw_cross(max_blob.cx(), max_blob.cy()) # cx, cy

        pan_output=pan_pid.get_pid(pan_error,1)/2
        print("pan_output",pan_output)
        pan_servo.angle(pan_servo.angle()+pan_output)