Ariy at 09:17, 24 March 2019

2019-03-24T09:17:57Z

Ariy: Created page with "=== Python Example 2 === Detect right/left turn from IMU * IMU angles are represented in Quaternions https://en.wikipedia.org/wiki/Quaternion hence translated to RPY (roll..."

2019-03-24T09:04:26Z

Created page with "=== Python Example 2 === Detect right/left turn from IMU * IMU angles are represented in Quaternions https://en.wikipedia.org/wiki/Quaternion hence translated to RPY (roll..."

New page

=== Python Example 2 ===
Detect right/left turn from IMU
* IMU angles are represented in Quaternions [[https://en.wikipedia.org/wiki/Quaternion]] hence translated to RPY (roll pitch yaw)
* RPY are in radians, translated to degrees

<syntaxhighlight lang="python" line='line'>

#!/usr/bin/env python
import rospy
import math
from sensor_msgs.msg import Imu
from tf.transformations import euler_from_quaternion, quaternion_from_euler

def calculate_robot_angle(orientation):
quaternion = (
orientation.x,
orientation.y,
orientation.z,
orientation.w)
euler = euler_from_quaternion(quaternion)
roll = euler[0]
pitch = euler[1]
yaw = euler[2]
return math.degrees(yaw)

prev_angle = 0
def callback(msg):
global prev_angle
curr_angle = calculate_robot_angle(msg.orientation)
if curr_angle > prev_angle :
print "TURINING LEFT"
else:
print "TURINIGN RIGHT"
prev_angle = curr_angle

rospy.init_node('imu_values')

#Put your Hamster number instead of agent<number>
#The agent number is printed on the Hamster cover
sub = rospy.Subscriber('/agent14/imu', Imu, callback)

rospy.spin()
</syntaxhighlight>

To execute save this example in example2.py and type in the terminal

<syntaxhighlight lang="bash" line='line'>
$ python example2.py
</syntaxhighlight>

@@ Line 1: / Line 1: @@
 === Python Example 2 ===
-Detect right/left turn from IMU
+Detect right/left turn from Inertial Measurement Unit (IMU)
 * IMU angles are represented in Quaternions [[https://en.wikipedia.org/wiki/Quaternion]] hence translated to RPY (roll pitch yaw)
 * RPY are in radians, translated to degrees
@@ Line 51: / Line 52: @@
   $ python example2.py
 </syntaxhighlight>

HamsterPythonExample2 - Revision history

Ariy at 09:17, 24 March 2019

Ariy: Created page with "=== Python Example 2 === Detect right/left turn from IMU * IMU angles are represented in Quaternions https://en.wikipedia.org/wiki/Quaternion hence translated to RPY (roll..."