1 00:00:00,480 --> 00:00:01,920 The third section of this course. 2 00:00:02,250 --> 00:00:09,660 In this section, we are going to be dealing with real time things, meaning we are going to first interact 3 00:00:09,660 --> 00:00:13,890 with the software that is visible and without any delay. 4 00:00:13,890 --> 00:00:14,790 Let's get into it. 5 00:00:15,120 --> 00:00:23,880 I am going to create a new launch file and name it to be gazebo dot launch start by its contents are 6 00:00:23,880 --> 00:00:24,720 already copied. 7 00:00:24,720 --> 00:00:27,360 So I would just paste it and I will explain. 8 00:00:27,360 --> 00:00:29,010 What is it containing? 9 00:00:31,350 --> 00:00:36,900 A lot of import libraries and these two are the previous launch Wild Things. 10 00:00:37,020 --> 00:00:41,670 The new things are from this point to this point. 11 00:00:42,940 --> 00:00:51,290 Oh, because he was basically just a software and gazebo and Ross needs to talk to each other with some 12 00:00:51,290 --> 00:00:52,190 sort of API. 13 00:00:52,760 --> 00:01:01,320 And Gazebo also provides a service that requires a call and it brings a robot from a USDA to a gazebos 14 00:01:01,330 --> 00:01:02,780 into gazebo simulation. 15 00:01:03,250 --> 00:01:04,160 These two things. 16 00:01:04,160 --> 00:01:09,560 First, Gazebo needs to talk to ROS, which is very important for us. 17 00:01:09,860 --> 00:01:11,840 It can automatically. 18 00:01:11,840 --> 00:01:13,340 It can without the. 19 00:01:14,370 --> 00:01:15,090 It can. 20 00:01:16,740 --> 00:01:25,650 It can bring a robot into its simulation, but without any Ross interference, without any Ross communication 21 00:01:25,650 --> 00:01:25,980 stuff. 22 00:01:26,160 --> 00:01:28,770 And we don't we don't need to do that. 23 00:01:29,900 --> 00:01:31,130 We don't need that. 24 00:01:31,520 --> 00:01:34,330 So first thing is execute command. 25 00:01:35,440 --> 00:01:36,450 Execute process. 26 00:01:36,460 --> 00:01:42,790 This is basically straight away a command which can be written in a terminal and it is just executing. 27 00:01:42,790 --> 00:01:48,010 If you write this command in the terminal, it is the same is equal minuses. 28 00:01:48,610 --> 00:01:49,440 Live busy for us. 29 00:01:49,480 --> 00:01:54,040 It's not calling any function or any node or any launch file. 30 00:01:54,040 --> 00:01:55,420 It is just a simple command. 31 00:01:56,170 --> 00:02:04,300 It is going to call this live legacy factory that will enable us to make visible and communicate with 32 00:02:04,300 --> 00:02:04,840 each other. 33 00:02:04,870 --> 00:02:15,530 Okay, then there is a next package which makes us able to spawn the robot invisible using rice stream 34 00:02:15,530 --> 00:02:20,170 for cooking, and that requires the name of the robot and the fight. 35 00:02:20,590 --> 00:02:20,960 Okay. 36 00:02:21,220 --> 00:02:28,730 This file is automatically being provided by this bot that we give it to that you you. 37 00:02:28,830 --> 00:02:37,150 If I think we did the same that yes, in our resort launch file we provided exact path to share package 38 00:02:37,750 --> 00:02:44,640 share shareholder of the package to launch files for to these join state publishing and go forward state. 39 00:02:44,950 --> 00:02:51,250 Similarly, we are going to provide that you are but in this you fold it to the spawn entity so it can 40 00:02:51,250 --> 00:02:52,780 spawn the robot in gazebo. 41 00:02:53,140 --> 00:03:01,780 And that's what the basic solution looks like, bringing the robot into gazebo right now let's perform. 42 00:03:03,690 --> 00:03:11,370 The execution of I'll close all the gazebo servers available that we're already running across to our 43 00:03:11,370 --> 00:03:17,370 before that we need to perform all can build a new gazebo that launched or firefly has been created 44 00:03:17,370 --> 00:03:21,270 in the launch folder so it needs to be copied into the shared folder. 45 00:03:21,630 --> 00:03:25,500 Rose to launch Baseboard Gazebo. 46 00:03:26,520 --> 00:03:27,480 Launched by. 47 00:03:27,510 --> 00:03:28,440 Let's take a look. 48 00:03:28,710 --> 00:03:30,180 It is going to be a little funny. 49 00:03:31,400 --> 00:03:35,120 It's sponsored and brings the robot in gazebo simulation. 50 00:03:35,130 --> 00:03:36,890 And here we have our robot. 51 00:03:37,520 --> 00:03:38,120 Whoa. 52 00:03:38,660 --> 00:03:46,910 It is flying in the simulation, although was the simulation to take a look onto the robot. 53 00:03:47,330 --> 00:03:48,530 What is the problem here? 54 00:03:51,490 --> 00:03:52,850 I have a neighbor. 55 00:03:53,790 --> 00:04:01,710 Inertia from this view drop down and we can see there are a lot of lines, but no inertia boxes being 56 00:04:01,710 --> 00:04:02,370 represented. 57 00:04:02,370 --> 00:04:03,390 Oh. 58 00:04:04,380 --> 00:04:08,100 You know, Showbox is being applied on to these bodies. 59 00:04:08,100 --> 00:04:09,620 Let's zoom out and. 60 00:04:09,650 --> 00:04:10,380 Oh, my God. 61 00:04:11,970 --> 00:04:19,920 You see, this is the size of the mesh and the inertia for this mesh is this much bigger. 62 00:04:21,050 --> 00:04:22,640 And this is a huge problem. 63 00:04:22,820 --> 00:04:24,950 They actually forces are applied on the road. 64 00:04:24,950 --> 00:04:29,870 And for this reason, this robot is behaving in such a manner. 65 00:04:30,230 --> 00:04:33,560 The base inertia box is very small. 66 00:04:33,560 --> 00:04:36,230 The wheels and the caster inertia is huge. 67 00:04:36,530 --> 00:04:37,760 We have to fix that. 68 00:04:38,120 --> 00:04:45,410 And I'll show you the simplified form in which the robot does not floats in the air or acts weirdly. 69 00:04:45,890 --> 00:04:49,940 So let me unpause the simulation and let's see what it looks like. 70 00:04:50,590 --> 00:04:51,230 Okay. 71 00:04:52,480 --> 00:04:53,790 It is spinning very fast. 72 00:04:53,800 --> 00:04:59,650 If we disable inertia and see the robot and it is going away just like a ball. 73 00:05:00,170 --> 00:05:00,700 Whoa. 74 00:05:01,790 --> 00:05:03,950 And I have lost it all. 75 00:05:03,980 --> 00:05:05,720 It is going so. 76 00:05:06,820 --> 00:05:09,550 We have some serious problems in our. 77 00:05:11,160 --> 00:05:12,000 You are fine. 78 00:05:12,300 --> 00:05:13,450 We have to fix them. 79 00:05:13,470 --> 00:05:15,770 Okay, let's get to the audio file. 80 00:05:16,320 --> 00:05:19,710 And I have removed the bass frame. 81 00:05:20,040 --> 00:05:20,490 Wow. 82 00:05:21,960 --> 00:05:23,930 Let's start with the first link. 83 00:05:25,700 --> 00:05:27,020 In inertial values. 84 00:05:27,020 --> 00:05:29,450 There are some inertial values randomly given. 85 00:05:29,660 --> 00:05:32,180 Let's not come to the initial value directly. 86 00:05:32,480 --> 00:05:37,670 First, we will take a look into the collision properties which are again, very important. 87 00:05:38,240 --> 00:05:39,740 Now collision properties. 88 00:05:41,000 --> 00:05:44,660 Should be exactly the same as the visual geometric. 89 00:05:44,660 --> 00:05:50,090 In visual geometry, we are providing a mesh and in collision we are providing a box. 90 00:05:50,630 --> 00:05:52,280 So they are very different. 91 00:05:52,290 --> 00:05:57,980 Now I am providing collision for visual and collision same geometries. 92 00:05:57,990 --> 00:06:01,610 Okay, let's check the other things again. 93 00:06:02,240 --> 00:06:04,940 Mesh is provided in visual and in collision. 94 00:06:04,940 --> 00:06:05,960 This is provided. 95 00:06:06,140 --> 00:06:10,780 I'm showing you this for only one reason so you can debug your idea. 96 00:06:10,780 --> 00:06:11,600 ADF issues as well. 97 00:06:11,900 --> 00:06:20,300 I've created many, many, many many you ideas but many of the time in initial stages I was not clear 98 00:06:20,300 --> 00:06:21,440 why this is happening. 99 00:06:21,440 --> 00:06:25,850 So first we will solve the collision issues, visual and collision tags. 100 00:06:25,850 --> 00:06:26,800 Geometry should be same. 101 00:06:26,810 --> 00:06:31,340 Let's take a look on its output as it affects the simulation or not. 102 00:06:33,590 --> 00:06:34,010 Okay. 103 00:06:34,010 --> 00:06:34,580 Logic. 104 00:06:35,890 --> 00:06:39,550 And I think I should keep my mouth on the pause button. 105 00:06:40,600 --> 00:06:45,960 And still we have some serious problems with our robot, if I can posit. 106 00:06:45,970 --> 00:06:46,670 Whoa. 107 00:06:47,470 --> 00:06:50,740 Okay, so are you are if is not ready right now. 108 00:06:51,010 --> 00:06:54,280 So as we have seen, collision properties are safe. 109 00:06:54,430 --> 00:06:57,400 Visual properties are safe, but our robot is not sick. 110 00:06:57,880 --> 00:07:01,780 We need to fix the main thing that is inertial matrix. 111 00:07:02,050 --> 00:07:07,120 And in the next video we are going to see how we are going to utilize MATLAB to solve this problem.