PRE2015 3 Groep2 week4

Drone Specifications

The Parrot AR.Drone 2.0 is a remote controlled flying quadcopter. It was designed to be controlled by mobile or tablet with operating systems such as iOS or Android.

Dimensions:	451x451	(517x517 with Indoor Hull)
Weight:	380 g	(420 g with Indoor Hull)
Battery life:	12 min	(in theory)
Charging time:	60 to 90 minutes
Interfaces:	USB and Wi-Fi

The drone comes with a frontal HD camera (720p, 30FPS) and a QVGA bottom camera (480p, 60FPS), both with the possibility of direct streaming. The height of the drone is measured with onboard ultrasound sensors.

Approaching Users

Multiple factors can play a role for users to feel safe and comfortable with the drone approaching them. Little research has been done regarding approaching people in a user friendly way, as can be seen in the chapter Research from week 3. In order to be able to construct constrains and preferences for the approaching, four variables have been devised:

• Variable 1: Flying speed
• Variable 2: Approaching height
• Variable 3: Landing distance
• Variable 4: Flying path

The first two variables are technical constraints and thus attached to the approach. Variables 3 and 4 are coming from 2 experiments where values are computed for the optimal landing distance (relative to the user) and for a preferred flying path when approaching the user.

Flying speed

The flying speed of the drone is important for approaching people. If the drone flies to hard, people can get afraid but if it flies to slow it would take to long. Humans average walking speed is researched to be 1.4 m/s second, and it is assumed that it is the right speed to test with. For safety and the accuracy reasons of the experiments however, the speed of the drone has been set slightly lower; approx v = 1 m/s.

Approaching height

For the approaching height, a height of 1 meter is chosen. This is because of the following: Lower heights would result in issues with obstacle avoidance, whereas higher heights might pose danger for the user. Eye-height of possible users might vary from 1.50 m to 2.20 m, making this domain unsuitable for flight. Given the accuracy of the drone for keeping the height another 0.5 meter is implemented as safety feature.

Experiment 1: Landing distance

Figure 1: Foto of the first experiment for determining the landing distance. Strips on the ground are giving the distance per 0.5m.

The variable landing distance is about. Have the test subject stand on a given spot (l=0). The distances 1, 2, 3…7 meters are marked with masking tape (distance to test subject). The drone will start at a distance of 7 meters (= l_start) and 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 (l_end).

Experiment	Optimal distance (m)	Nearest distance (m)
1	2.25	1.0
2	2.75	0.75
3	2.5	1.0
4	2.25	0.75
5	2.0	0.75
6	1.75	0.5

Experiment 2: Way of approach

Figure 2: Schematic representation of the experiment setup. Situation A, displayed in red. Situation B, displayed in green. Situation C, displayed in blue.

It's not online interesting to look at the best landing distance, but also at the way the drone approaches the user. A distinction is made between three different situations. For a description of these situation see the list below and figure 1. In all the situations the test person is positioned at l = 0. The drone starts at a distance l_start and height h_start.

Situation A

The drone flies horizontally to a certain distance l_end then the drone lands vertically.

Situation B

The drone flies diagonally, at an angle α, to a certain point at distance l_end and height h_end. Then the drone lands vertically.

Situation C

The drones lowers itself vertically to a certain height h_end. It then flies horizontally to a certain distance l_end before it lands vertically on the ground.

During the experiment the three situation will get different values for the distance l_start and l_end. These distances will be 6, 4 and 2 meters. Note that the drone will never fly away from the test person. So when the distance l_start equals 4 meters, only the values of 4 and 2 meter will be used for l_end.

After each test variation the test person is asked to rate the experience with the values very bad/bad/neutral/good/very good.