7/12/2021
Description:
Custom messages in the Robot Operating System.
Synopsis:
Methods to create custom message types will be researched.
Data:
Custom messages were created and implemented into the existing nodes. Custom messages can hold any number of variables, of different types. Custom messages will be used to hold the data in the software.
7/13/2021
Description:
Custom data messages sent between nodes.
Synopsis:
Two custom messages types will be created to match the data that will be sent in the software tool.
Data:
Custom messages, according to the data structures, were created.
7/14/2021
Description:
Publishing and receiving data messages.
Synopsis:
The custom message types will be implemented into the nodes.
Data:
Custom messages were created and implemented into the existing nodes.
7/15/2021
Description:
Calling callbacks in subscriber nodes.
Synopsis:
Methods to call callbacks in subscribers nodes will be researched and implemented.
Data:
In subscriber nodes, callbacks are called in order to received messages that are published to a certain topic. The standard method of doing this is with rospy.spin(), which keeps a node from exising until it has been shutdown. However, this method is blocking and the user cannot take full control of the node. Therefore, an alternate method, that is not blocking, must be found. It was found that in C++ nodes, there is rospy.spinOnce(), which can be put into a loop. However, this method does not exist in python nodes.
7/16/2021
Description:
Alternative methods to call callbacks in subscriber nodes.
Synopsis:
Other ways to call callbacks in subsciber nodes will be found and tested.
Data:
An alternate method to rospy.spin() was found: while not rospy.core.is_shutdown():
rospy.rostime.wallsleep(0.5)