Raspi Servo抖动，在应该静止的时候来回移动

Question

(关于格式的问题很抱歉)我正在尝试写一个opencv程序来跟踪红色。到目前为止，它工作正常，但伺服是抖动的，当对象静止和中心时，伺服来回移动。我有一个470uf的电容器和一个外部电源。任何让它变得更顺畅的帮助都将是天赐的！

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from picamera.array import PiRGBArray 
from picamera import PiCamera
import time 
import cv2
import numpy as np
import RPi.GPIO as GPIO
import time


###SERVO SETUP###
servoPIN_x = 17
servoPIN_y = 18
GPIO.setmode(GPIO.BCM)
GPIO.setup(servoPIN_x, GPIO.OUT)
GPIO.setup(servoPIN_y, GPIO.OUT)
px = GPIO.PWM(servoPIN_x, 50)
py = GPIO.PWM(servoPIN_y, 50)
position_x = 7.5
position_y = 7.5
px.start(position_x)
py.start(position_y)

x_gain = 0.1#0.01 - 5.00
y_gain = 0.3#0.01 - 5.00

xon = True
yon = True

###CAMERA SETUP##
camera = PiCamera()
camera.resolution = (640, 480)
camera.framerate = 32
raw_capture = PiRGBArray(camera, size=(640, 480))
time.sleep(0.1)


###VIDEO CAPTURE LOOP### 
for frame in camera.capture_continuous(raw_capture, format="bgr", use_video_port=True):
    #cv2 video init
    image = frame.array
    hsv_frame = cv2.cvtColor(image,cv2.COLOR_BGR2HSV)
#color parameters
low_red = np.array([161,155,84])
high_red = np.array([179,255,255])

#find color
red_mask = cv2.inRange(hsv_frame, low_red, high_red)#create black/white mask for all reds
contours,_ = cv2.findContours(red_mask,cv2.RETR_TREE, cv2.CHAIN_APPROX_SIMPLE)#find different red contours
contours = sorted(contours, key=lambda x:cv2.contourArea(x), reverse=True)#sort contours from largest to smallest

#set line x/y var to center
x_medium=320
y_medium=240

#loop sets x/y_medium
for cnt in contours:
    (x,y,w,h) = cv2.boundingRect(cnt)
    y_medium = int((y+y+h)/2)
    x_medium = int((x+x+w)/2)
    cv2.rectangle(image,(x,y),(x+w,y+h),(0,255,0),2)
    break

#draw lines
cv2.line(image,(x_medium,0),(x_medium,480), (0,255,0),2)
cv2.line(image,(0,y_medium),(640,y_medium), (0,255,0),2)

#cv2.imshow('mask', red_mask)
#show regular frame
cv2.imshow("Frame", image)
key = cv2.waitKey(1) & 0xFF
raw_capture.truncate(0)

#quit 
if key == ord("q"):
    cv2.waitKey(1)
    px.stop()
    py.stop
    break



#servoX travels to place postion_x in center frame
if not xon and x_medium != 320:
    px.start(position_x)


if x_medium > 320:
    position_x = position_x - x_gain
    
elif x_medium < 320:
    position_x = position_x + x_gain
elif x_medium == 320:
    position_x = position_x
    xon = False
else:
    position_x = 7.5
    
if xon:
    px.ChangeDutyCycle(position_x)
else:
    px.stop



px.stop()
py.stop()
cv2.destroyAllWindows()
exit(0)

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Answer 1

在建造机器人时，我也遇到了这种伺服电机的问题。我用另一个名为"pigpio“的库解决了这个问题，用来控制rasperry pi的引脚。从那时起，伺服系统就不再无缘无故地移动了。这些命令非常相似。看一看：

http://abyz.me.uk/rpi/pigpio/