WEBVTT 00:00.080 --> 00:02.510 We are now at the last step for this project. 00:02.540 --> 00:03.620 Step number six. 00:03.620 --> 00:07.070 And here we are not going to add any new functionality. 00:07.100 --> 00:12.830 We are just going to make the application more dynamic and scalable with parameters and launch files. 00:12.860 --> 00:13.160 Okay. 00:13.190 --> 00:16.790 So you can start the application with different values for different parameters. 00:16.790 --> 00:18.830 You don't need to change the code at all. 00:18.830 --> 00:22.370 And you can also start everything from just one file. 00:22.370 --> 00:24.290 And let's start with the parameters. 00:24.290 --> 00:31.340 So we are going to go to the code of Total controller and Total Spawner and see what could be a parameter. 00:31.370 --> 00:36.200 And well here for example you see that we have a catch closest total first. 00:36.200 --> 00:37.850 So that's something we can choose. 00:37.850 --> 00:40.940 But it's hard coded in the nodes. 00:40.940 --> 00:42.830 So we will need to modify the code. 00:42.830 --> 00:45.380 Instead of that we can add a parameter. 00:45.380 --> 00:50.810 So I'm going to do self dot declare parameter. 00:50.990 --> 00:59.810 And let's name it simply catch closest total first. 00:59.840 --> 01:03.240 And let's put a default value of true. 01:03.510 --> 01:04.050 Okay. 01:04.050 --> 01:09.060 So then we can just going to reverse the order here. 01:13.140 --> 01:26.430 So this one instead of true we can say self get parameter with the name and then dot value. 01:26.670 --> 01:28.860 And again no parentheses here. 01:28.890 --> 01:29.280 All right. 01:29.280 --> 01:31.320 So you can see it's very easy to create a parameter. 01:31.320 --> 01:34.740 You declare it and then you do get parameter dot value. 01:34.770 --> 01:36.900 Okay let's save that. 01:36.900 --> 01:39.480 And then we can go to turtle spawner. 01:39.480 --> 01:41.910 And here I'm going to add two parameters. 01:41.940 --> 01:42.240 Okay. 01:42.270 --> 01:47.190 We're going to be able to change the turtle prefix I have just used turtle for now. 01:47.190 --> 01:50.790 But let's say you want to use my turtle or any other name. 01:50.790 --> 01:53.160 You can choose it with the parameters. 01:53.160 --> 01:58.530 And also well, that's something I have actually changed in the code to make some different tests. 01:58.560 --> 02:03.220 The frequency at which we're gonna spawn turtles. 02:03.250 --> 02:06.340 Okay, that could be very useful as a parameter. 02:06.850 --> 02:08.920 So let's start here. 02:09.370 --> 02:11.800 Self declare parameter. 02:12.130 --> 02:14.620 So let's name this one turtle. 02:14.650 --> 02:16.150 Name prefix. 02:17.020 --> 02:18.130 The default value. 02:18.160 --> 02:21.250 We're going to use the same one as in the code turtle. 02:21.850 --> 02:25.750 And then self declare parameter with. 02:25.780 --> 02:29.410 So for example spawn frequency. 02:29.440 --> 02:33.400 Here I'm going to use frequency instead of period. 02:33.430 --> 02:33.610 Okay. 02:33.640 --> 02:35.080 It's just the opposite. 02:35.080 --> 02:43.450 To get the frequency you do one divided by the period. 02:43.990 --> 02:44.410 Okay. 02:44.410 --> 02:51.400 So to get the period you will need to do actually one divided by frequency. 02:51.430 --> 02:52.030 All right. 02:52.030 --> 02:54.460 So it's basically the same thing. 02:54.460 --> 02:57.610 We just need to modify something here in the code. 02:57.970 --> 03:01.880 And let's say the default frequency is going to be one hertz. 03:01.880 --> 03:11.660 So then I have my turtle name prefix which is going to be so self get parameter. 03:12.350 --> 03:13.640 The name is here. 03:15.830 --> 03:20.630 Dot value and then self dot. 03:20.690 --> 03:23.360 Here I'm going to create a spawn frequency. 03:24.560 --> 03:37.610 We don't have this variable yet is equal to self get parameter with spawn frequency and dot value. 03:38.150 --> 03:39.050 All right. 03:39.050 --> 03:45.410 So then turtle name prefix is correctly set the spawn frequency I don't use it. 03:45.410 --> 03:47.150 So I'm going to have to use it here. 03:47.150 --> 03:56.630 I'm going to simply do 1.0 divided by self dot spawn frequency. 03:56.630 --> 03:59.520 So if I give ten it means ten hertz. 03:59.550 --> 04:01.950 It means ten turtles per second. 04:01.950 --> 04:04.770 And this is going to be 0.1. 04:04.800 --> 04:05.190 Okay. 04:05.220 --> 04:06.720 That's how the frequency works. 04:06.750 --> 04:07.170 All right. 04:07.170 --> 04:09.570 And that's basically it. 04:09.570 --> 04:10.710 So I can save. 04:10.740 --> 04:12.300 Now you could already. 04:12.330 --> 04:17.790 Well if you want you can start the nodes already here and start with the parameters. 04:17.790 --> 04:22.230 I'm going to go directly to the next thing which is to create the launch file. 04:22.230 --> 04:24.330 And so where do we create launch files. 04:24.330 --> 04:27.390 Well you need a dedicated bringup package for that. 04:27.390 --> 04:32.520 So you can either create one new package for that and set it up and everything. 04:32.520 --> 04:35.970 But I already have my robot bring up in this workspace. 04:35.970 --> 04:37.320 So I'm going to use that. 04:37.320 --> 04:44.010 And in the launch folder I'm going to create a new file named turtle SIM. 04:44.280 --> 04:46.170 Catch them all. 04:46.170 --> 04:50.640 Well you can name it as you want dot launch dot XML. 04:51.180 --> 05:00.280 Let's open and close the launch tag And then what nodes do we need to start? 05:00.310 --> 05:04.000 Well, the first node is actually the turtle sim node. 05:04.000 --> 05:08.590 So if I come back here you see we do restaurant turtle sim. 05:08.620 --> 05:09.760 Turtle sim node. 05:10.210 --> 05:11.710 So node with pig. 05:12.580 --> 05:15.340 Turtle SIM exec. 05:16.540 --> 05:18.460 Turtle sim node. 05:19.300 --> 05:19.570 Okay. 05:19.600 --> 05:21.190 That's the first node we need. 05:21.550 --> 05:25.300 The second node where we could start both. 05:25.330 --> 05:29.950 It doesn't matter the order, but we're going to start the controller from turtle SIM. 05:29.950 --> 05:30.820 Catch them all. 05:30.850 --> 05:31.690 That's the package. 05:31.690 --> 05:34.060 And controller is the executable. 05:34.840 --> 05:42.490 So node, pig turtle sim catch them all. 05:43.510 --> 05:46.540 Exec controller. 05:47.260 --> 05:54.070 And the third node is also going to be from the same package here. 05:54.070 --> 06:01.550 And the executable you can see Ease if I come back is spawner. 06:06.290 --> 06:06.740 All right. 06:06.740 --> 06:12.620 So we've just that we can start what we started in those three terminals here. 06:12.740 --> 06:14.660 And now I'm going to add the parameters. 06:14.660 --> 06:23.090 So you could add the parameters as we saw previously here with param and then name and then value. 06:23.090 --> 06:28.850 But what I'm going to do instead is I'm going to create a YAML file that I will load directly for all 06:28.850 --> 06:29.690 the nodes. 06:29.690 --> 06:31.790 So how to create a YAML file. 06:31.790 --> 06:34.220 I'm going to go to my config folder here. 06:34.220 --> 06:44.240 And I don't know let's name this catch them all config dot YAML for example. 06:44.240 --> 06:47.450 And let's put the parameters for each nodes. 06:47.480 --> 06:50.120 Do we need parameters for the turtle sim node? 06:50.150 --> 06:50.810 No. 06:50.810 --> 06:54.680 You could actually add parameters if you wanted to change the background. 06:54.710 --> 06:54.890 Okay. 06:54.920 --> 06:58.210 You know that you have three colors red blue and green. 06:58.210 --> 07:02.470 You could change the background if you want to, but I'm not going to do that here. 07:02.530 --> 07:06.730 I'm going to add parameters for the controller and actually the node. 07:06.790 --> 07:11.050 So if you run the node I'm going to run that same node data. 07:11.080 --> 07:14.800 Same with the controller and the spawner. 07:15.070 --> 07:19.360 And if I do Ros two uh node list. 07:20.410 --> 07:23.800 You see that's the node here turtle controller and turtle spawner. 07:25.270 --> 07:25.510 Okay. 07:25.540 --> 07:26.980 So that's what we need. 07:28.150 --> 07:37.690 So slash turtle controller and then Ros underscore underscore parameters. 07:38.260 --> 07:40.120 And what parameters we have. 07:40.120 --> 07:42.040 Well we just take it from here. 07:42.070 --> 07:45.850 Catch closest turtle. 07:46.360 --> 07:48.400 And I'm just going to put it to true. 07:48.430 --> 07:48.730 Okay. 07:48.760 --> 07:51.160 Even if it's the default value I'm going to use. 07:51.160 --> 07:51.520 True. 07:51.520 --> 07:55.240 Because yes I want to catch the closest turtle first. 07:55.450 --> 07:56.960 Then I can do. 07:56.990 --> 07:58.850 So what was the name? 07:59.090 --> 08:00.440 Turtle spawner. 08:03.530 --> 08:06.980 And then Ross parameters. 08:08.150 --> 08:11.150 And here we have two parameters. 08:11.150 --> 08:13.790 So we have turtle name prefix. 08:16.310 --> 08:21.080 Let's name this one my turtle to change it. 08:21.080 --> 08:24.110 And we have the spawn frequency. 08:26.060 --> 08:26.450 Okay. 08:26.480 --> 08:28.490 The default is one hertz. 08:28.970 --> 08:31.220 Let's say 1.5Hz. 08:31.700 --> 08:32.900 So it's a bit faster. 08:32.900 --> 08:36.620 And that's all the parameters that I can provide. 08:36.920 --> 08:38.960 Let's save this file. 08:38.960 --> 08:45.680 And then in that one we are going to provide the parameters directly from that YAML file. 08:45.680 --> 08:50.960 So for that node here I'm going to open and close the node tag. 08:51.380 --> 08:53.300 And I'm going to put the param. 08:53.990 --> 08:57.310 And if you don't remember the syntax we had it here. 08:57.310 --> 09:01.120 So from and then find PG share. 09:01.150 --> 09:05.680 So from and then dollar sign parentheses. 09:05.710 --> 09:08.620 Find pg share. 09:08.620 --> 09:12.100 The name of the package is my robot. 09:12.880 --> 09:18.160 Bring up and then slash config slash. 09:18.190 --> 09:21.550 Catch them all. 09:22.240 --> 09:24.310 Config dot YAML. 09:25.960 --> 09:26.680 All right. 09:26.680 --> 09:30.670 And the good thing about that is we can just duplicate the code. 09:30.670 --> 09:34.240 So I also open and close that node like this. 09:34.270 --> 09:39.100 And I can just basically take the same right here. 09:39.130 --> 09:40.210 It's the same file. 09:40.240 --> 09:40.660 Okay. 09:40.690 --> 09:45.730 So you can see our launch file is now nine lines of code long. 09:45.730 --> 09:50.290 And we start three nodes including parameters for two nodes. 09:50.380 --> 09:50.800 All right. 09:50.830 --> 09:57.100 So the first node the second node so the controller node with the params and the spawner node with the 09:57.100 --> 10:00.040 params that are all in this YAML file. 10:00.070 --> 10:04.210 Now we can go back here and we will need to build this time. 10:05.050 --> 10:09.040 Call and build the packages. 10:09.250 --> 10:13.090 Select my robot. 10:13.300 --> 10:14.590 Bring up. 10:17.410 --> 10:20.590 So yeah actually I miss a space here. 10:21.040 --> 10:28.990 And actually before I build one thing we can do because we are going to use, you see, from that, 10:28.990 --> 10:35.380 uh, launch file, we are starting nodes from the turtle package and the turtle sim catch them all package. 10:35.380 --> 10:37.690 So let's go to package dot XML. 10:37.690 --> 10:49.390 And you see we have an exact deployment here that we can add exact depends with turtle sim exact depend. 10:49.390 --> 10:52.570 And then another exact depend. 10:53.650 --> 10:54.350 Turtle SIM him. 10:54.350 --> 10:55.250 Catch them all. 10:56.690 --> 10:58.760 Okay, so we make things a bit cleaner. 10:58.760 --> 11:05.150 So in case those packages were not installed, then we will get an error directly when we try to do 11:05.150 --> 11:06.170 a call on build. 11:06.770 --> 11:08.030 So let's do that. 11:08.990 --> 11:09.470 Okay. 11:09.500 --> 11:10.520 It was very quick. 11:10.550 --> 11:12.770 And then well actually we don't need to do much. 11:12.770 --> 11:18.050 We just source the environment and we do. 11:18.080 --> 11:20.330 Ros two launch. 11:21.140 --> 11:21.800 Turtle. 11:22.160 --> 11:25.370 No actually it's from my robot. 11:25.610 --> 11:30.380 Bring up and launch file is called turtle SIM. 11:30.380 --> 11:31.430 Catch them all. 11:31.460 --> 11:33.380 Dot launch dot XML. 11:33.410 --> 11:37.130 Let's see what happens if I run this and you see. 11:37.130 --> 11:39.590 Well the application is just working. 11:39.590 --> 11:41.870 We have I'm going to do Ctrl C here. 11:42.380 --> 11:46.100 And let's come back here to the beginning. 11:46.100 --> 11:48.230 You see we start three processes. 11:48.260 --> 11:48.530 Okay. 11:48.560 --> 11:51.110 The turtle SIM node the controller and the spawner. 11:51.380 --> 11:56.820 And we have all the logs here that are mixed together in this launch file. 11:57.060 --> 12:00.300 Okay, so let's start again. 12:03.060 --> 12:03.360 All right. 12:03.360 --> 12:06.450 You can see the turtle is chasing the other turtles. 12:06.450 --> 12:09.990 And even here you see it changed to go to the closest one. 12:10.440 --> 12:11.190 All right. 12:11.220 --> 12:13.800 And that's going to continue again and again. 12:13.800 --> 12:16.290 And you can see the turtle name. 12:16.380 --> 12:18.750 So you see my turtle here. 12:18.780 --> 12:21.360 The prefix is my turtle. 12:21.870 --> 12:22.050 Okay. 12:22.080 --> 12:26.730 So that's because we have provided the configuration here my turtle. 12:26.730 --> 12:32.610 And now the cool thing about that is let's say you want to start the application with different parameters. 12:32.850 --> 12:34.620 You just stop. 12:35.100 --> 12:37.710 And we don't even need to go to the code. 12:37.800 --> 12:40.080 So we don't need to go to turtle spawner. 12:40.080 --> 12:42.450 We don't need to go to turtle controller. 12:42.630 --> 12:45.210 We don't even need to go to the launch file. 12:45.750 --> 12:55.450 We just open the config file and we say okay, instead of my turtle I want test And instead of 1.5, 12:55.450 --> 12:59.110 I want let's say very high frequency 5.0. 12:59.140 --> 13:01.150 I'm going to keep this one to true here. 13:01.150 --> 13:04.090 But you see I just for example, changed those settings. 13:04.450 --> 13:14.020 I save then of course I need to build, I need to source and I can run again. 13:15.250 --> 13:17.530 And you see now what is going very fast. 13:17.530 --> 13:19.960 We have five turtles per second. 13:19.990 --> 13:20.830 Okay. 13:21.040 --> 13:26.980 But you see, it just takes a few seconds to change those values. 13:26.980 --> 13:28.030 Save. 13:28.630 --> 13:30.700 And here. 13:30.880 --> 13:33.310 Well, maybe we had too many things. 13:34.120 --> 13:34.660 Okay. 13:34.690 --> 13:41.770 Build and source and run. 13:42.640 --> 13:43.030 All right. 13:43.030 --> 13:47.590 And we start the same application with a complete different set of configs. 13:49.450 --> 13:49.840 And. 13:49.840 --> 13:50.800 Congratulations. 13:50.800 --> 13:53.110 The project is now finished.