Sorry for the late reply!
Let me try to help out if still necessary.
Differences between Motion commander and High level commander
It is technically all closed loop but it is mostly where the trajectory is generated and where the setpoint handling lies. The Motion commander generates the trajectory on the pc site and send each setpoint over radio. With the high level commander, it will only receive an high level command from the cflib (like take off), and onboard will handle all the trajectory and setpoint handling. The
second hour of this lecture we did for EPFL explains the differences between these commanders.
the difference between position hl commander and high level commander:
Technically the HL commander and HL position commander are doing exactly the same thing, but for the HL position commander, there are some added functionality from CFLIB to make things easier. In the simple example script, you see that we send a take off command, wait for a little bit and than land again and wait for that as well. Those functions are none blocking but we always need to add a time.sleep to it to prevent the script to send another command 'too soon'. The HL position commander class actually incorporates those sleeps already in their command functions, so these function block until the full action (taking off, go forward 1 meter, landing) is fully executed.
So technically all is fine to try out your drone, however you have to make sure that it also sends the external position at the same time. I have a simple example of the regular HL commander here which only takes off, hovers a bit and lands:
Code: Select all
import sys
import time
import cflib.crtp
from cflib.crazyflie import Crazyflie
from cflib.crazyflie.log import LogConfig
from cflib.crazyflie.syncCrazyflie import SyncCrazyflie
from cflib.crazyflie.syncLogger import SyncLogger
from cflib.utils import uri_helper
# URI to the Crazyflie to connect to
uri = uri_helper.uri_from_env(default='radio://0/80/2M/E7E7E7E7E7')
def wait_for_position_estimator(scf):
print('Waiting for estimator to find position...')
log_config = LogConfig(name='Kalman Variance', period_in_ms=500)
log_config.add_variable('kalman.varPX', 'float')
log_config.add_variable('kalman.varPY', 'float')
log_config.add_variable('kalman.varPZ', 'float')
var_y_history = [1000] * 10
var_x_history = [1000] * 10
var_z_history = [1000] * 10
threshold = 0.001
with SyncLogger(scf, log_config) as logger:
for log_entry in logger:
data = log_entry[1]
var_x_history.append(data['kalman.varPX'])
var_x_history.pop(0)
var_y_history.append(data['kalman.varPY'])
var_y_history.pop(0)
var_z_history.append(data['kalman.varPZ'])
var_z_history.pop(0)
min_x = min(var_x_history)
max_x = max(var_x_history)
min_y = min(var_y_history)
max_y = max(var_y_history)
min_z = min(var_z_history)
max_z = max(var_z_history)
# print("{} {} {}".
# format(max_x - min_x, max_y - min_y, max_z - min_z))
if (max_x - min_x) < threshold and (
max_y - min_y) < threshold and (
max_z - min_z) < threshold:
break
def reset_estimator(cf):
cf.param.set_value('kalman.resetEstimation', '1')
time.sleep(0.1)
cf.param.set_value('kalman.resetEstimation', '0')
wait_for_position_estimator(cf)
def activate_high_level_commander(cf):
cf.param.set_value('commander.enHighLevel', '1')
def run_sequence(cf):
commander = cf.high_level_commander
commander.takeoff(1.0, 2.0)
time.sleep(6.0)
commander.land(0.0, 2.0)
time.sleep(2)
commander.stop()
if __name__ == '__main__':
cflib.crtp.init_drivers()
with SyncCrazyflie(uri, cf=Crazyflie(rw_cache='./cache')) as scf:
cf = scf.cf
activate_high_level_commander(cf)
reset_estimator(cf)
run_sequence(cf)
What you have to add is to implement the external position send to the crazyflie.