PRE2015 3 Groep2 week5
Experiment 1: Landing distance
The variable landing distance is about the distance that users are still comfortable with the drone around. The optimal distance that users like and the nearest distance that people are comfortable with drones around are determined with an experiment. The subject (an user) stands on a given spot (l=0). The distances 0.5, 1, 1.5…7 meters are marked with masking tape (distance to test subject) on the ground. The drone will start at a distance of 7 meters (= lstart) as seen in figure 1. The drone will approach the person at a steady speed of approximately v = 1 m/s. It does so at a height of h = 1 meter. Whenever the test subject feels like the current distance between him and the drone is the most comfortable distance to land, the test subject will give off a sign and the drone will be given the order to land (lend). The subject will redo the test to determine the nearest distance where he or she feels comfortable. Those distances are measured and rounded per 0.25m. The results are seen below.
|Optimal distance (m)
|Nearest distance (m)
The mean value of the optimal distance is 2.47m with an standard deviation of 0.67. The nearest distance has a mean of 1.00m with an standard deviation of 0.53. These means give the landing distance from this experiment, the optimal landing distance is 2.5m with a nearest landing distance of 1.0m. The drone should be programmed to keep these distances as first option and starting point of the landing procedure.
Points of improvement
Though the experiment came with a clear conclusion, with a few outliners, some variables that might influence the results have not been touched upon. The experiment above gives a general idea for a distance to keep from the users, but does for instance not distinguish between different users. These differences may for example concern:
- Experience (with drones)
- Length of the user
- And even general (in)security or character of the user
But also the drone itself can have influence on results:
- Approaching speed
- Size of the drone
- Appearance of the drone
- Wind generated
Further research will have to point out to what extend these factors play a role in approaching users with drones.
Experiment 2: Way of approach
It's not only interesting to look at the best landing distance, but also at the way the drone approaches the user. For this, a distinction is made between three different situations. For a description of these situation see the list below and figure 2. In all these situations the test person is positioned at l = 0m. The drone starts at a distance lstart and height hstart.
- Situation A
- The drone flies horizontally to a certain distance lend then the drone lands vertically.
- Situation B
- The drone flies diagonally, at an angle α, to a certain point at distance lend and height hend. Then the drone lands vertically.
- Situation C
- The drones lowers itself vertically to a certain height hend. It then flies horizontally to a certain distance lend before it lands vertically on the ground.
For the distance lstart a distance of 8m is chosen. The ending distance lend is chosen according to the results of experiment 1 at roughly 2.5 meters.
After each test variation the test person is asked to rate the experience with the values very bad/bad/neutral/good/very good.
Point of improvement
During the experiment some notes ware mate about the quality of the experiment.
- The drone has been flown manually, so the same ways of approaching are different with each test subject
- The test group only exists of males
- The test group only involves three people, so the result aren't trustworthy
As can be seen from figure 3 the best way of approaching the user is while flying at an angle. Flying horizontally to the user seems better at first, but since the error is bigger than it is at approaching at an angle it's safer to use this way of approaching. Keep in mind that their where only three test subjects used, the results aren't trustworthy and more test subjects have to be used to give a trustworthy conclusion.
Something that is clear is that the user prefers an approach at which the drone is under the eye level at close distances. A possible explanation for this is that when the drone is under eye level the user has to look down. Looking down unto the drone gives people the feeling that their more dominant, i.e. in control of the situation. Looking upwards, when the drone tries to land vertical for example, gives the opposite feeling, that the drone is in control. In a situation where the user isn't into control it can be wise to at least give the user the feeling their into control.
During the experiment the landing distance of 2,5 meters is chosen, but maybe the way of approach differs at different landing distance. Do find this out their will also be looked at the likability of approaches with a landing distance of 1,5 and 3,5 meters.
A major problem during the autonomous landing phase is that the drone needs to know where it is on the map it is creating. It's not wise to assume that the drone flies at a constant speed, since it doesn't. Doing so would create an error which can result in complete disaster.
Since the test setup has been moved inside, the situation created won't be realistic, but very controllable. Determining the location of the drone will be done with markers placed on the ground or objects which the drone can detected with its down facing camera. These markers will be placed 50cm from its neighboring marker.
In the first situation the system will be developed in a two dimensional world. Their will be height differences and the drone can be front- and backwards. No movement to the left or right will be possible. If the drone succeeds to land in such a randomized environment their will be looked at the second situation.
In the second situation a third dimension will be added, the left and right movement. This will be a more realistic environment, but far from the environment a drone will encounter in a real world scenario.
In both the situations their will only be objects the drone can detected from the height it uses to scan the environment. Since the markers are used to determine the location of the drone, they will be placed on a level surface. This could be an object or the ground. Their will also be enough space to land the drone in a user friendly way.
In designing a technique it is not merely about finding a technical working system that solves the problem. User preference play a big role in the success or failure of such a technique. The first question appears: What are the user preferences concerning this system? Two user preferences that will be tested for are: The distance to keep between the user and the drone, also the optimal distance for landing. And the way of approaching the user. These experiments will be further explained in the chapter 4 Research. Below the question of 'Who is this user and what are his or her preferences?' is answered.
Users can be categorized into three different categories. Primary users are the users that the technique is aimed at, the main people to interact with. In the case of the delivery drone these are the people that will have their package handed over by the drone:
- Consumers, people who order online
Secondary users are the people who also will be making use of the technique, but have less direct contact with the drone than the primary users. Some secondary users of the delivery drone are listed below.
- Companies and shopkeepers
- Drone developers
- Drone manufacturers
The last group of users are the tertiary users. This group often contains the users that are only incidentally confronted with the technique, people working in the same environment or people who perform maintenance on the drones for example:
- Safety instances (in case of accidents)
- People walking/using the streets
- Other airspace users
- Government instances (new laws)
The main focus of the project will be interaction with the drones of the primary users. Therefor an in depth analysis of these users and their needs is needed. Other users however may play a part in this project as well, so for some their needs will be illustrated briefly as well.
General primary user needs for drone delivery are fast, trustworthy and safe delivery of their packages. Note that no discrete values can be given to what is fast, trustworthy or safe delivery. In the scope of the project these needs however are slightly different. Safety still remains a priority, the user should in no way be exposed to risky and or dangerous situation regarding the drone. Since the flight of the drone to the address is assumed to be no problem, fast delivery falls a little more to the background. Trustworthy delivery remains an user need, but its meaning changes with the context. Here trustworthy delivery is not so much about not damaging or losing the package on the way, but rather about a being able to find a location to land no matter the environment. Last an extra user desire comes within focus, the comfortability of the delivery. This involves the drone's behavior towards the user which should not only be safe, but also feel safe and comfortable.
Companies and shopkeepers will be the ones providing the service of drone delivery. Therefor they will take a large portion of the responsibility for the drones. Their needs will lay in reliability of the drones. Another important need for companies is for the drones to be cheap, or at least affordable. A right balance between price and quality must be found. Also for they are to provide the service to the consumers, consumers needs automatically become needs for companies and shopkeepers as well.
Of course with the increasing use of drones, developers and drone-producingcompanies will be able to make money with it. Also new developments will be stimulated. For companies producing drones, the ease of producing will be an important need as well as the expense of separate parts.
Generally, taking full responsibility as the drone producer can be seen as a generous gesture towards customers and will also push the development of autonomous vehicles onto the main audience. Other autonomous machine producers have already done so: "Volvo, Google and Mercedes have now all said that they will accept full liability if their self-driving vehicles cause a collision".
The primary need for mechanics is that the drones are easy to repair or preform maintenance on, as well as safety doing.
A need or wish for safety instances it to have the drones to be able to fly without accidents, for their priority is to provide a safe living environment. And in case of an accident, which will unfortunately be inevitable, the damage must be minimal.
For people walking/using the streets the main need concerning drone delivery is to be able to walk the streets safely without the fear or risk of an accident.