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Drone Crashed!

bucko
Fri, 19 Jan 2018 03:01:03 GMT

As per my previous post I did go do another mission which resulted in a crash. Technically it was my fault due to a tree. However this did reveal a flaw with Harmony. At takeoff my drone ascended to the 1st WP set at 10 meters. The tree was between this WP and was 15 meters. So My drone flew right into it. Amazingly I chopped up a lot of tree but managed to fly it out! But once I let go of the controls, the programming took control again and flew it right back in, this time with fatal results. The P4's VPS did not avoid the tree because of Harmony. So this part I do blame you guys. My P4 took off and aimed itself based on the 1st WP camera direction, so the P4 VPS was not looking the direction of flight. Part of your waypoint settings should include fly to waypoint looking forward (unless defined to look at a POI), arrive at WP, THEN point the cam. I should have the option between WP to tell the UAV which way to look. My accident would not have happened otherwise.

davidadjiashvili
Fri, 19 Jan 2018 09:38:38 GMT

Hi bucko, We are very sorry to read that you crashed your drone! We are always working on ways to increase the safety of flight with DH and feedback like your is very valuable to us. From your description, however, the app acted as we would have expected it to. Since you seemingly did not switch modes on the controller when you started using the sticks, the pre-programmed flight continued when you left the sticks. It also seems right that the drone did not necessarily face the direction of flight-- the direction of the drone is determined by the camera angle that was set of the two waypoints between which the drone is traveling. We might add an option in the future to always fly in "forward", but then the camera angles that were initially set will be ignored. Finally, it is important to understand the concept of obstacle avoidance used in DH: unlike the obstacle avoidance sensors on the drone that reacts to the environment in real time, DHs obstacle avoidance is happening in the planning phase, based on the input the user supplies about the environment. In other word s, DH computes plans around the obstacles that the user has defined. The user can then use the 3D view to preview the flight and verify that it is safe (again, assuming that the relevant obstacles in the scene have been outlined). Here are some tips that can help you avoid such situations in the future: 1. The most important thing to remember when using DH (and for this matter any other flight planner) is that you can and SHOULD take over the per-programmed flight if something goes wrong. The best and most reliable way to do this is to switch modes on the controller (in the P4 case to "sport" mode). Once you've done the drone immediately starts hovering in place and the pre-planned flight is aborted. You can then calmly navigate the drone to safety by flying it manually. By only using the sticks WITHOUT switching modes, you are not stopping the pre-programmed flight. This way you are only affecting it, e.g. by accelerating or decelerating the speed of execution. We try to warn the user and various ways about this option (e.g. when you launch there is a message in the dialogue reminding you of this, and it is also covered in the tutorial about flying). There are other ways to halt the flight of the drone: you can tap on the pause icon during the execution, but this option is intended for non-emergency situations. 2. When you use DH Obstacle avoidance you need to be sure to outline all relevant obstacles in the scene and then create a mission. If you forget some obstacle, or you manually move waypoints into obstacles after you generated a mission, DH does not intervene. If the obstacles are correctly outlines, using the 3D preview to see the entire mission is a good way of verifying that all obstacles are indeed avoided, whether some waypoints have been moved after mission generation or not. It is important to remember that DH knows about the environment only what the user tells it about it, so and obstacle that is not outlined, or a height that is miscalculated will not be otherwise "spotted" by DH. 3. DH does not override the obstacle avoidance sensors in the DJI drones. Having them on is an additional safety measure that we are happy to incorporate the in the entire process. since you crash seems to have happened while flying the drone upwards, there were no sensors on the P4 to help it react to this. 4. If you are not sure about the safety of the flight you are about to execute, we recommend to first fly it in minimal speed to allow ample time to react (see point 1.). You can then either restart the mission at a higher speed, or just accelerate with with the tachometer tool. I truly hope that this is the last time you crash a drone and are happy to continue the discussion with you to see what we can all do better in the future. Best David

bucko
Sat, 20 Jan 2018 00:09:23 GMT

Hi David, Thanks for the reply. As I said originally, I accept fault for this crash. However please understand that my takeoff point had about a 10 meter column of clear space set around a stand of trees. By the time my UAV started to the 1st waypoint, there was little time for me to react. Yes I forgot to switch modes after the 1st save, so it just went back into the tree again. My fault. Lesson learned. I still stand that it is better by default you should have the UAV pointing in the direction of travel on it's way to the 1st waypoint. If a planner wants a different cam angle, he would have to just change his plan. I think you have this part backwards. This makes a lot more sense for safety sake. A plan actually starts at WP #1 anyway. My 2nd argument for this change is relative to another test I did yesterday. I did a simple orbit pan . I wanted the UAV to just circle me @10m altitude. I was forced to set a takeoff point outside of my orbit pan as per your software restrictions. So my UAV takes off and starts to the takeoff point . It started flying to the takeo ff point BEFORE getting to altitude! That could have been a bad thing, but I was in an open field to test this out. This behavior to takeoff point relates somewhat to the same issue of my crash. Under any plan the UAV should go to altitude of the plan BEFORE moving. For myself, I will now always add a WP directly above my takeoff point for added safety . I would set it's altitude another 10 meters higher than my plan AND set the cam view right along the path to the 1st WP. BTW, I do fly the mission at minimum speed and use my stick to speed it up traveling to the 1st WP. You guys do have a nice product. I am anxious to see a polished final product having used several others that just don't work well enough for me to support. Keep up the good work.

davidadjiashvili
Thu, 25 Jan 2018 15:15:00 GMT

Hi bucko, Thanks for the clarifications and your good feedback! Now I understand better what has happened. I agree, the way that the drone approaches the first waypoint can indeed be improved. We have noted down to consider your suggestion to, at least for the flight from take off location to the first waypoint always fly facing forward. I agree that it is rare that the user need to capture data in this initial part of the flight, and making it fly forward should result in a safer flight due to obstacle avoidance on the drone. Thanks for this feedback! The orbit flight plan (just as many others in DH) does not let you set takeoff and landing waypoints inside 3D volumes that you define. I see that you have noticed that. We are working on refining this aspect as well, letting the user more flexibility without allowing dangerous situations to happen. Regarding first flying to the height of the first waypoint and only then flying to it in the x-y coordinates- we have thought about this and for now decided against doing this in every plan. There are situations in which th is is counter-intuitive behavior, while in others it is intuitive. In the future we will perhaps allow the user to choose which behavior to use, but for now we strongly recommend to use the 3D view to inspect the flight trajectory before takeoff. This gives a very good visual idea of trajectory to be flown. Again, many thanks for the feedback on this point that we debated extensively. I do hope that you, from now on, have only very positive experiences with DH. We are looking forward to more feedback from you. Best, David

bucko
Fri, 26 Jan 2018 00:48:24 GMT

I appreciate your response and comments. I think you got yourself a good product for us flyers and look forward to working with it more.