Project ScratchDuinoRobotKit blackline

Name of author (s)

User:Elena Vostrikova

Description of the ROBBO Scratch project

Trip time	Sketch	Power supply	ROBBO Scratch	Trip time	Arduino IDE
Algorithm 1. The robot uses ONE numerical value of the line sensor — the AVERAGE of two extreme values, obtained when the sensor is positioned above the white area and above the black line. If the sensor shows a value greater than the average, then the robot turns to the left during 0.1 second and goes forward during 0.1 second. If the sensor shows a value less than the average, then the robot turns to the right during 0.1 second and goes forward during 0.1 second. The trajectory the robot follows is a zigzag.
38 seconds		USB	ROBBO Scratch Video Download the sketch	30 seconds	To turn the robot on and off, two touch sensors are used: analogRead(A3) – right-hand rear sensor — ON, analogRead(A1) — left-hand rear sensor — OFF Download the sketch
13 seconds	The high speed causes numerous errors. At a high speed, the robot misses the turns in half the cases.	Battery 7.4V	ROBBO Scratch Video Download the sketch	11 seconds	Arduino IDE Video Download the sketch
Algorithm 2. The robot uses SEVEN (FIVE, in case of USB) numerical values of the line sensor — these are values between two extreme values, obtained when the sensor is positioned above the white area and above the black line. The readings of the line sensor are as follows: » 0 means the position above the white area. Both motors are on and in full swing (255), the left-hand motor is rotating forward, the right-hand motor is rotating backward. The robot turns in place during 0.1 second. » 1 means the position above the white area, closer to the black line. The left-hand motor is on and in full swing (255), rotating forward, while the right-hand motor is off. The robot turns on the fly during 0.1 second. » 2 means the position at the border of the white and black areas, even more closer to the black line. The left-hand motor is on and in full swing (255), rotating forward, while the right-hand motor is at its half power (120), rotating forward, too. The robot goes ahead and turns a bit, on the fly, during 0.1 second. » 3 means the position at the border of the white and black areas, already above the black line. The left-hand and the right-hand motors are on and in full swing (255), both rotating forward. The robot goes ahead during 0.1 second. » The rest of the values (4, 5, and 6) are mirroring the 0, 1, and 2 options, respectively. The trajectory the robot follows is a smooth curve with long tangent sections, so the robot can travel all along without slowing down.
25–26 seconds	ROBBO Scratch handles the timing data with worse quality than Arduino IDE, therefore we have reduced the number of the ranges to 5 and simplified the action of motors. The motors are rotating forward all the time, with varying power.	USB	Download the sketch	18 seconds	Arduino IDE Video Download the sketch
12 seconds	At a high speed, the robot misses the turn in 4 of 5 cases.	Battery 7.4V	It is important to modify the sketch coded for USB, because at a high speed, the intermediate values of the sensor cannot be handled. We join all the intermediate values. Download the sketch	9.5 seconds	It is important to immediately modify the sketch, coded for a 5V power supply (USB). Replace the robot's turning time of 0.1 seconds by 0.01 seconds. And increase the time of going ahead up to 0.2 seconds. It is necessary because at a high speed, the robot rushes too fast along the path section where the values of the sensors are changing.
Algorithm 3. The robot uses EIGHT numerical values of the line sensor — these are values between two extreme values, obtained when the sensor is positioned above the white area and above the black line. The trajectory the robot follows is a line with long straight sections, and the robot can travel all along without slowing down.
XX seconds
XX seconds				8.5 seconds (track record!)	Arduino IDE Video Download the sketch

Description of travelling along the black line with TWO sensors

It is impossible to travel along a complicated track with crossings, forks, "zebras", and inverted sections using only one sensor.
When two sensors are used, special algorithms are needed to automate the robot's motion.

XX seconds XX seconds XX seconds

Trip time	Sketch	Power supply	ROBBO Scratch	Trip time	Arduino IDE
Algorithm 4. Relay controller. This algorithm is intended to keep the robot in the position "Both sensors of the robot are above the white line", that is, to the left and to the right from the black line. If both sensors are above the black line, the robot stops.
XX seconds		USB	When powered by USB, the robot stops at the turn, because both sensors get above the black line. Download the sketch	XX seconds	analog0 = analogRead(A0); // Got a value from the sensor analog1 analog4 = analogRead(A4); // Got a value from the sensor analog4 limit = 50; time1 = 200; power = 255; //if both sensors "see" white, the robot moves straight: if (analog0 < limit && analog4 < limit) { move_robbo (power, power, 0, 0, time1); } //if the left sensor "sees" black, the robot turns to the left: if (analog0 > limit && analog4 < limit) { move_robbo (0, power, 0, 0, time1); } //if the right sensor "sees" black, the robot turns to the right: if (analog0 < limit && analog4 > limit) { move_robbo (power, 0, 0, 0, time1); }
10 seconds		7.4 V	When extra powered from the battery, the robot misses the sharp turns, because at a speed, the sensors cannot be above the black line both at the same time. ROBBO Scratch Video Download the sketch	XX seconds	Arduino IDE Video. If the battery is run down, the robot stops at the turn. Download the sketch - sensor readings Download the sketch - relay controller + ON/OFF by touch sensors
Algorithm 5. Proportional controller. Proportional controller is a device whose controlling action depends on the его отклонению от заданного состояния. Принцип действия П-controller основывается на том, что мы находим значение отклонения от заданного состояния, которое назовем error и обозначим буквой E. Ошибка – это разница между показаниями датчиков линии: E = S1 – S2. To obtain the value of controlling action U, we multiply this value by a chosen ratio kp: U = kp⋅E. U is the momentum that we have to add to one motor and extract from other motor. Thus, the robot will control its position itself — that is, for turning or taxing to the required direction.
XX seconds.		USB	ROBBO Scratch Video	XX seconds	[[1] Download the sketch]
	7.4 V	[[Media:ROBBO Scratch Video Download the sketch]]	XX seconds	[[Media:Arduino IDE Video Download the sketch]]
<center>Algorithm 6. Пропорционально-дифференциальный controller
	USB
	7.4 V	ROBBO Scratch Video Download the sketch	XX seconds	Arduino IDE Video Download the sketch
Algorithm 7. ПИД-controller
XX seconds		USB
XX seconds		Battery 7.4 V	ROBBO Scratch Video Download the sketch	XX seconds	Arduino IDE Video Download the sketch