Obstacle Avoidance Controller for Robot | Webots Simulator | [Tutorial 8]

[@floriksz]

For people who don't turn, check to see if the wheels are in the right order. The correct order of wheels in the code is left front (1), right front (2), left rear (3), right rear (4). Also if your wheels are not spinning but rolling, turn the robot in the direction where the wheels are spinning, also the red line is the direction of the wheels.

[@anprabh1]

Thank you very much! Not changing the anchor parameters caused the wheels to revolve instead of rotate.

[@christophkastner1357]

nice

[@coolrobotics]

Thank you

[@jokercrazy3330]

For my 4-wheel robot, when I set the velocity for all four wheels to the same value then my robot can move forward as expected but if I would set the velocity for four wheels with different values, for example when I want it to move right or left, it doesn't work so my robot can only go straight forever. Can you guess where I might have gone wrong that resulted in this error?

[@coolrobotics]

You can set both right wheels with same velocity and left wheel with the same(but can be different then right wheel) in order to steer

[@jokercrazy3330]

@@coolrobotics yes, i have tried to do that but it doesn’t work. Is it because my design or friction or may be something else?

[@coolrobotics]

@@jokercrazy3330 Have you made any changes in friction

[@robotics9965]

Same my problem 🥲

[@bd9249]

What is the setting it tells that the robot would move in the direction of the sensor and not in opposite direction? Also, could you explain the logic of IF and FOR loop constructs.

[@coolrobotics]

Direction of robot is defined with sign of velocity is set-velocity. Or if you are doing position controller then value of position you give in set-position.

[@coolrobotics]

If loop is for making sure there is are no obstacles while we are going forward. And for loop is for checking obstacles through all the sensors.( In our case it is 2)

[@bd9249]

@@coolrobotics What I mean as how to ensure that the direction of move of the Robot is aligned with the position of the distance sensor put on the front i.e. how does it know that the robot should move(assuming + velocity) in the direction the distance sensors are positioned(Front of.the robot)

[@jingjing8081]

in the code about the distance sensor，i am wondering why 950 is used. The code like: “if (ds_values < 950.0) ”, if seting 1000, the car robot turn left wherever there are obstacles or not, and

[@coolrobotics]

We can choose any value below 1000 because if there is no obstacle it gives the value of 1000. If we choose a very small value it will result in detecting obstacles when it reaches too close to the robot. So you can choose your value and see how the simulation works and make changes accordingly.

[@yatishv8063]

When obstacles is detected then robot turns almost 360° and move but I wanted robot to just take either left or right and move in same direction which it was moving before detecting obstacle. I am not getting wat to change in program to do like that. Plz help me out as soon as possible, don't have much time.

[@coolrobotics]

For that case you will need to implement navigation algorithms. You will need to know the map before hand and will need to use planners for achieving the goal. Shorter way can be if you see and obstacle make a 90 degree turn. Go straight for some distance again make a 90 degree turn so that you are back on your direction. If you see obstacles again repeat the loop

[@coolrobotics]

You will need IMU for this application.

[@yatishv8063]

@@coolrobotics Der is a video wch is tutorial 11 wch is about IMU.... I vl try that once. For navigation can I program in Aruduno itself in case of prototype model.

[@coolrobotics]

If you are good at aurdino sure

[@yatishv8063]

@@coolrobotics Thank you very much for clarification bro

[@tomf6920]

Hi, nice tutorial, whenever i click play the whole robot sinks into the ground as if the ground is like water. Any ideas on how to fix it?

[@coolrobotics]

Add bounding objects to your nodes

[@tomf6920]

@@coolrobotics hi, I have however it's still falling through the floor

[@coolrobotics]

Did you add a bounding object of same size as node.

[@tomf6920]

@@coolrobotics I've just changed the physics to have mass of +1 as it was originally -1 and it's now working. However it is moving backwards not forwards aha

[@tomf6920]

@@coolrobotics okay I've moved the sensors to the other side but they dont stop the robot and turn it around it just keeps moving?

[@himansusekhardash5140]

can you make any video regarding the robot should reach the goal point after avoiding obstacles

[@kevantrade7649]

hi,is it possible to do a video on lidar?

[@emnaayari8238]

hi, how can i get a navigation controller to a specific target without collision with obstacles, thanks a lot for help

[@bd9249]

How to mark one tile with some letter('P') or image to denote parking area so that the robot can park only there. Any easy way to find the exact co-oridinates of corners of a tile

[@coolrobotics]

A very good question... You can use IMU and GPS readings. 1. Keep robot on that tile. (Which you want to mark as P). 2. Save the IMU and GPS data of that point. 3. Compare robot co-ordinates with the tile values. 4. If it is near the value trigger stop.

[@bd9249]

@@coolrobotics Thank You very much for the response. You are really a motivator for a learner like me. I have GPS and IMU filtted in to the robot. Is it possible I can compare the (X,Z) of GPS between the co-ordinates of a tile so as to stop on the designated tile, rather than comparing exactly one GPS co-ordinates as the robot may not reach that 'saved' point exactly but could be nearer. 2) I should the get the distance covered by the robot by multiplying the position sensor value of 1 front wheel(for example) at any given time by the radius of the wheel. Also, how can I rotate the robot on Z Axis by 90 when a certain condition is met e.g. the robot has travelled 30 meter and I would like to make the robot stand upright. Can I apply 0(zero velocity) to both rear wheels to make that possible?

[@teetanrobotics5363]

Video 6,8,9 of the Webots playlist not loading above 360p. I have tried it on multiple computers and multiple networks. Could you please check it out once ?

[@coolrobotics]

Omg, yes you are right. It had been loading in full HD all these days. Something has surprisingly gone wrong only on these 3 videos. I am looking into the issue, just contacted KZbin. Thank You so much for letting us know.

[@teetanrobotics5363]

@@coolrobotics Hey I need help in adding lidar to the 4 this robot. Could you please tell me the exact steps or if possible make a short video on the same ?

[@coolrobotics]

You can add lidar. Similar to GPS or IMU sensor. Just make a solid and make lidar as children of that solid

[@teetanrobotics5363]

@@coolrobotics I saw the code for the lidar on the website documentation. It is very short and I am not able to understand how to add it

[@GiuseppeGiu96]

@@coolrobotics I was became mad ahhah, it isn t my proplem only

[@marceltorne2985]

Hi, could you share some info on how to create an OpenAI gym using Webots and then train the RL agent efficiently please? It would be awesome if you could, Thanks!

[@coolrobotics]

This is a great application. I will suggest you to follow webots discord which link can be found in cyberbotics website You will get expert advise there .

[@josephcampugan2439]

good day, do you have a python version of this tutorial? godbless and stay safe

[@coolrobotics]

Sorry for that but nope

[@josephcampugan2439]

@@coolrobotics okay sir, thank you

[@pal432-m5v]

My robot passes right through the walls i made from your earlier tutorials.

[@alaaskender2502]

Thank you for great tutorial, when I run the simulation the robot does not move , it stays immobile!!

[@enbakomghebremichael5406]

Could you show as Obstacle Avoidance controller with python

[@shridhardodamani2728]

can you please help me in creating proto file.

[@coolrobotics]

cyberbotics.com/doc/guide/tutorial-7-your-first-proto You can refer this link. And let me know if any issue.

[@shridhardodamani2728]

@@coolrobotics Thank you , I have referred it. But unable to get proto file. But I have empty proto folder

[@valeriasalas4700]

Is the code available for use?

[@coolrobotics]

The code is available in the description of the video.

[@Ahmadtar-no6sz]

please CAN YOU SHARE THE FILES OF THIS PROJECT