Dear Readers,

when launching the experiment “DVS Drone Experiment” (available in Templates when ?dev is added to the url), the drone is crashing instead of going first up and waiting for events to fly.

A fix is to modify the “launch_trajectory” tranfer function with :

from geometry_msgs.msg import Twist

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Example of the way to control the quadrotor’s motion.

The drone should always start with a positive linear speed on the z-axis, simulating its take-off

‘’’

from geometry_msgs.msg import Twist

‘’’

Example of the way to control the quadrotor’s motion.

The drone should always start with a positive linear speed on the z-axis, simulating its take-off

‘’’

@nrp.MapRobotPublisher(‘trajectory’,Topic(’/quadrotor/cmd_vel’, Twist))

def launch_trajectory(t, trajectory):

from geometry_msgs.msg import Twist, Vector3

```
z_speed = 0. # m/s
y_speed = 0.
angular_speed = 0. # rad/s
# going up to engage motors
if t < 3:
z_speed = 0.5 # m/s
trajectory.send_message(Twist(linear=Vector3(x=0., y=y_speed, z=z_speed),
angular=Vector3(x=0., y=0., z=angular_speed)))
elif t < 4:
z_speed = 0 # m/s
trajectory.send_message(Twist(linear=Vector3(x=0., y=y_speed, z=z_speed),
angular=Vector3(x=0., y=0., z=angular_speed)))
return None
```