Start trajectory synchronously for several crazyfile

[CYDXYYJ]

I try to start trajectory synchronously for several crazyfile by this code:

    swarm = Crazyswarm()
    allcfs = swarm.allcfs

    traj = uav_trajectory.Trajectory()
    
    for i in range(Num):
        traj.input_trajectory(agent[i].traj)
        allcfs.crazyflies[i].uploadTrajectory(0, 0, traj)

    allcfs.startTrajectory(0,relative=False)

But I find they ran a false trajectory even if they did not run the same trajectory.

However, I used following code and they ran the correct trajectory even if it is not synchronous.

    for i in range(Num):
        traj.input_trajectory(agent_list[i].traj)
        allcfs.crazyflies[i].uploadTrajectory(0, 0, traj)

    for i in range(Num):  
        allcfs.crazyflies[i].startTrajectory(0,relative=False)

Therefore, how to start a correct trajectory synchronously for several crazyfile?

[whoenig]

What does .input_trajectory do in this case - this is non-standard? Also, you should create the traj object inside your first for-loop, see https://github.com/USC-ACTLab/crazyswarm/blob/master/ros_ws/src/crazyswarm/scripts/swap6v.py#L36-L52 for an example. Finally, in your first code snipped, you use agent[i], while the second has agent_list[i] - is that intentional?

[CYDXYYJ]

.input_trajectory is a function defined by myself as a member of class Trajectory in uav_trajectory.py as following :

  def input_trajectory(self, data):
    self.polynomials = [Polynomial4D(row[0],row[1],row[2],row[3],row[4]) for row in data]
    self.duration = 0
    for i in range(len(data)):
      self.duration+=data[i][0]

It is similar to def loadcsv(self, filename):.
agent[i].traj is the trajectory data like figure8.csv in your demo.

agent_list[i] and agent[i] are the same variables, they have no difference.

[whoenig]

Your two code versions should be equivalent. The only problem I see is that you use allcfs.crazyflies[i] rather than allcfs.crazyfliesById[i]. The former is an array that has potentially a random order (depending on how you used chooser.py last). The second one is a dictionary and probably what you want in this case.

[CYDXYYJ]

You say I should input trajectory by allcfs.crazyfliesById[i].uploadTrajectory(0, 0, traj)?

[whoenig]

Yes, otherwise you may get a random order which is not what you intended.