Problems with /cmd_vel_legacy.

[Wallat1]

Hi.

Could you please help me telling me what could be wrong with the following program,

#!/usr/bin/env python3

import rclpy
from rclpy.node import Node
from geometry_msgs.msg import Twist
import time

class vel(Node):
    def __init__(self):
        super().__init__('cmd')
        self.publisher_ = self.create_publisher(Twist, '/cf231/cmd_vel_legacy', 10)
        
        
        timer_period = 0.01  # seconds
        self.timer = self.create_timer(timer_period, self.timer_callback)
        

    def timer_callback(self):
        
        
        msg = Twist()          
        msg.linear.x = 0.0
        msg.linear.y = 0.0
        msg.angular.z = 0.0
        msg.linear.z = 0.0
        time.sleep(0.01)
  
        msg.linear.x = 1.0
        msg.linear.y = 1.0
        msg.angular.z = 0.0
        msg.linear.z = 40000.0

        self.publisher_.publish(msg)
        self.get_logger().info('Publishing: "%s"' % msg)
        
        
def main(args=None):
    rclpy.init(args=args)
    cmd = vel()
    rclpy.spin(cmd)
    cmd.destroy_node()
    rclpy.shutdown()

if __name__ == "__main__":
    main()

since I can't get the Crazyflie motors to turn on, as a capture system I use Optitrack with VRPN, in Rviz the position data and the quaternion are shown, so I think that this part is well configured, on the other hand, when executing 'ros2 topic echo /cf231/cmd_vel_legacy', I can see that the values ​​established in the code are published but even so the crazyflie does not do anything, I would appreciate your help.

Regards.

[whoenig]

The firmware has a safety feature to prevent sudden flights. Send a few messages with 0 target values first to "arm" the motors.

[Wallat1]

Hi.

Thank you so much for your help, this problem has been fixed.

Regards.

[ntukenmez3]

• I would like to ask one more question at that point, how could you access /cmd_vel topic? I would like to send roll, pitch, yaw rate and thrust to crazyflie.

[knmcguire]

@ntukenmez3 start a new discussion please. An answer has already been selected for this one so it is considered 'handled'