[Frontiers in Computer Science] Chapter 2 Answers 2022 - Sensors and Control

chapter 2

2.1 Start the car

go (左轮功率，右轮功率，持续时长)

Use the go function to steer the car forward with 50% power for 2 seconds

go(50, 50, 2)	

Action Module -> Forward -> 50 -> 50 -> 2

and so on

2.2 Control the direction of the car

2.2.1 Car's left turn

Left wheel horsepower 20% , right wheel horsepower 90% , running time 1s

go(20, 90, 1)	

2.2.2 Car's right turn

The horsepower of the left wheel is 90% , the horsepower of the right wheel is 20 %**, and the running time is 1s

go(90, 20, 1)	

2.2.3 Rotate in situ

Left wheel horsepower -20% , right wheel horsepower 20%, running time 2s

go(-20, 20, 2)

2.2.4 Learn to control your car

Left wheel horsepower -100% / -80% / -60% / -40% /-20% , right wheel horsepower 100% / 80% / 60% / 40% / 20% , running time 1s

go(-100, 100, 1)
go(-80, 80, 1)
go(-60, 60, 1)
go(-40, 40, 1)
go(-20, 20, 1)

2.3 Control the car through the U-shaped track

Let's not talk about the trial part

go(100, 100, 2)
go(100, 30, 1.9)
go(100, 100, 1)
go(100, 20, 1.7)
go(100, 100, 2.2)

2.4 Control the car to complete the designated road

2.4.1 Advance an edge

go(100, 100, 2.45)

2.4.2 Turn right 90°

def turn_right():
  go(100, (-100), 0.65)
  go(10, (-10), 0.3)

turn_right()

2.4.3 Square route

def turn_right():
  go(100, (-100), 0.65)
  go(10, (-10), 0.3)
    
for count in range(4):
  go(100, 100, 2.45)
  turn_right()

2.5 Understanding and Application of Vehicle Sensors

2.5.1 Understanding Sensors

1 -> 左前传感器
2 -> 右前传感器
3 -> 前传感器
4 -> 后传感器

2.5.2 Ultrasonic sensors

Car stops automatically (1)

setTarget(3)
time = 0.1
while get_ultrasound()[2] > 100:
  go(100, 100, time)

Car stops automatically (2)

setTarget(4)
time = 0.1
while get_ultrasound()[2] < 800:
  go((-100), (-100), time)

2.5.3 Color Sensor

Car color detection (1)

setTarget(6)
while get_color()[0][0] < 128:
  go(100, 100, 0.1)

Car color detection (1)

setTarget(7)
while get_color()[0][0] < 128:
  go(100, 100, 0.1)
while get_color()[1][0] < 128:
  go((-100), (-100), 0.1)

2.6 The trolley patrols the line

2.6.1 Tracking module design

def getLineLoc():
    colors = get_color() #4 * [R,G,B,L]
    res = -1
    res_max = 0
    for i in range(4):
        if colors[i][0] > res_max:
            res_max = colors[i][0]
            res = i
    return res

while get_color()[0][2] < 128:
    res = getLineLoc()
    if res == 0:
        go(-20,40,1/10)
    elif res == 1:
        go(30,50,1/10)
    elif res == 2:      
    	  go(50,30,1/10)
    elif res == 3:       
    	  go(40,-20,1/10)

2.7 Car distance measurement driving

2.7.1 Open loop control walking

go(50, 70, 4)
go(70, 50, 2)

2.7.2 Closed loop control walking

get_distance()

start = get_distance()[0]

if start - get_distance()[0] > 0:
    turn(10)
    
start = get_distance()[0]

if start - get_distance()[0] > 0:
    turn(-10)
    
dt = 50
while get_color()[0][2] < 128:
  if get_ultrasound()[0] - get_ultrasound()[1] > dt:
    go(20,80,1/12)
  elif get_ultrasound()[1] - get_ultrasound()[0] > dt:
    go(80,20,1/12)
  else:
    go(90,90,1/12)

2.8 Ranging of the trolley on complex routes

2.8.1. Turning with ranging sensor

dt = 50
while inCurrentTask():
  if get_ultrasound()[0] - get_ultrasound()[1] > dt:
    go(20,80,1/6)
  elif get_ultrasound()[1] - get_ultrasound()[0] > dt:
    go(80,20,1/6)
  else:
    go(90,90,1/4)