Continuous signal with crazyflie_ros

[eduardo-del]

Hello guys

I would like to know if you can help me with something, I am working with crazyflie_ws in the crazyflie_ros folder, https://github.com/whoenig/crazyflie_ros specifically there is a file named pose.publish.py https://github.com/whoenig/crazyflie_ro ... sh_pose.py and this generates the desired points for x, y and z, but these are only constants, I would like to know if I can enter a variant signal in time as it is a signal sine,

thank you very much.

[eduardo-del]

I try to do a sine signal with the next pose.publish.py file, I modify this file in the lines

t = rospy.get_time() x = 0 y = 0 z = 0.3*math.sin(2*3.1416*0.05*t) + 0.6

#!/usr/bin/env python

import rospy import math import tf from geometry_msgs.msg import PoseStamped

if name == 'main': rospy.init_node('publish_pose', anonymous=True) worldFrame = rospy.get_param("~worldFrame", "/world") name = rospy.get_param("~name") r = rospy.get_param("~rate") t = rospy.get_time()

x = 0 y = 0 z = 0.3*math.sin(2*3.1416*0.05*t) + 0.6

msg = PoseStamped()
msg.header.seq = 0
msg.header.stamp = rospy.Time.now()
msg.header.frame_id = worldFrame
msg.pose.position.x = x
msg.pose.position.y = y
msg.pose.position.z = z
quaternion = tf.transformations.quaternion_from_euler(0, 0, 0)
msg.pose.orientation.x = quaternion[0]
msg.pose.orientation.y = quaternion[1]
msg.pose.orientation.z = quaternion[2]
msg.pose.orientation.w = quaternion[3]

pub = rospy.Publisher(name, PoseStamped, queue_size=1)

while not rospy.is_shutdown():
    msg.header.seq += 1
    msg.header.stamp = rospy.Time.now()
    pub.publish(msg)
rate.sleep()

`

But really i haven't good result, maybe some one did some like this, can you help me? thank you

[eduardo-del]

I see my topic crazyflie/goal on rosbag and this only have a constat like z_goal = 0.6

[whoenig]

Your approach is correct, but make sure you update your message inside the main while loop (right before pub.publish(msg).

Please post code as file, or inside the code environment on github (you can use the "Preview" tab to check if what you post gets rendered correctly before commenting).

[eduardo-del]

Thank you for the answer @whoenig and for the advice :) i will tell you if this is working.

I have another quesiton, can you help me?

Do you think that I may the same with demo1.py file https://github.com/whoenig/crazyflie_ros/blob/master/crazyflie_demo/scripts/demo1.py ?

#x , y, z, yaw, sleep [0.0 , 0.0, 0.3*math.sin(2*3.1416*0.05*t), 0, 60]

[whoenig]

Sure, you can create an appropriate array using either numpy or Python list comprehension.

[eduardo-del]

Thank you so much @whoenig I will tray all this :)

[eduardo-del]

HI @whoenig

Again with other question Can I write a line with the acceleration of the z desired in crazyflie2.yaml file https://github.com/whoenig/crazyflie_ros/blob/master/crazyflie_controller/config/crazyflie2.yaml

for example in crazyflie2.yaml file

` Z:

kp: 5100.0
kd: 6900.0
ki: 3500.0
g: 9.81 
ed: -0.3*2*3.1416*0.05*2*3.1416*0.05*math.sin(2*3.1416*0.05*t)
m: 0.032
minOutput: 10000.0
maxOutput: 60000.0
integratorMin: -1000.0
integratorMax: 1000.0

`

ed is the acceleration

[eduardo-del]

Hi @whoenig I try the next code with publish_pose.py file

`

while not rospy.is_shutdown():
    msg.header.seq += 1
    msg.header.stamp = rospy.Time.now()
    msg = PoseStamped()  # add line
    msg.pose.position.z = z  # add line
    pub.publish(msg)
rate.sleep()

when I add two lines my joystick don't do anything my crazyflie don't receive commands like crazyflie/cmd_vel however my nodes exist

[eduardo-del]

I checked my crazyflie/cmd_vel and this is cero, i will check all the lines on my file thank you @whoenig

[whoenig]

• yaml files do not allow equations
• For your code, make sure you actually change the value of local variable z in every loop iteration.

In general, I recommend learning Python well first, then learn ROS in simulation only, and finally switch to real hardware.

[eduardo-del]

Thank you for the answer @whoenig :)

[aviad719]

Hii @whoenig . I am new to Python and to ROS and i want to do a project in ROS using Crazyflie. can you recommend on relevant tutorials ??

[whoenig]

In general I recommend first learning Python, then learning ROS in simulation, and afterwards picking up projects with real hardware. For both Python and ROS are good books available, which is perhaps easier/more structured than following tutorials online.