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Save flyboy74/2176de46d5777dafa6fcee891d230637 to your computer and use it in GitHub Desktop.
from picamera.array import PiRGBArray | |
from picamera import PiCamera | |
import time | |
import cv2 | |
import numpy as np | |
import RPi.GPIO as GPIO | |
GPIO.setmode(GPIO.BOARD) | |
GPIO.setup(40, GPIO.OUT) | |
GPIO.output(40, GPIO.HIGH) | |
camera = PiCamera() | |
camera.resolution = (640, 360) | |
camera.rotation = 180 | |
rawCapture = PiRGBArray(camera, size=(640, 360)) | |
time.sleep(0.1) | |
for frame in camera.capture_continuous(rawCapture, format="bgr", use_video_port=True): | |
image = frame.array | |
Blackline = cv2.inRange(image, (0,0,0), (60,60,60)) | |
kernel = np.ones((3,3), np.uint8) | |
Blackline = cv2.erode(Blackline, kernel, iterations=5) | |
Blackline = cv2.dilate(Blackline, kernel, iterations=9) | |
img_blk,contours_blk, hierarchy_blk = cv2.findContours(Blackline.copy(),cv2.RETR_TREE,cv2.CHAIN_APPROX_SIMPLE) | |
if len(contours_blk) > 0: | |
blackbox = cv2.minAreaRect(contours_blk[0]) | |
(x_min, y_min), (w_min, h_min), ang = blackbox | |
if ang < -45 : | |
ang = 90 + ang | |
if w_min < h_min and ang > 0: | |
ang = (90-ang)*-1 | |
if w_min > h_min and ang < 0: | |
ang = 90 + ang | |
setpoint = 320 | |
error = int(x_min - setpoint) | |
ang = int(ang) | |
box = cv2.boxPoints(blackbox) | |
box = np.int0(box) | |
cv2.drawContours(image,[box],0,(0,0,255),3) | |
cv2.putText(image,str(ang),(10, 40), cv2.FONT_HERSHEY_SIMPLEX, 1, (0, 0, 255), 2) | |
cv2.putText(image,str(error),(10, 320), cv2.FONT_HERSHEY_SIMPLEX, 1, (255, 0, 0), 2) | |
cv2.line(image, (int(x_min),200 ), (int(x_min),250 ), (255,0,0),3) | |
cv2.imshow("orginal with line", image) | |
rawCapture.truncate(0) | |
key = cv2.waitKey(1) & 0xFF | |
if key == ord("q"): | |
break | |
GPIO.output(40, GPIO.LOW) |
do you use the veriable error or angle
The error is used as the P input and the angle is used like the D input. I personally didn't uses a PID but rather used something similar to a PD controller. I used corrention = Kp * errror + Ka * angle. To understand how a PID works: P is a proportional correction, I is the integal or the accumulative error and used to correct in cases of steady state errors and D is the derivative or the trend the error is heading in and used to predict what will happen in the future to stop over shoot. So for line following you don't need the I part of a PID because u can't get steady state error in line following. I didn't use the D part of a PID because the angle tells you the same thing, the tend it is heading to in the future. So when I used the error and the angle it does the same thing as a PD controller but a little bit of a different way.
how did you calculate the speed of the motor? to make the forward movement and the turns : left and right
Hello
thx for the reply.
which veriable do you use as input for the pid