Which is a good way to send robot states between different ROS nodes?

Question

I am implementing a robotic system based on ROS. I have different nodes which send data multiple times per second. However, I don't need that. I want to send the robot state only when it is at a new location. What technique of ROS do you suggest to use?

Answer 1

Dependent on your requirements, you can either use the ROS Services or the Parameter Server.

ROS Service: The publish / subscribe model is a very flexible communication paradigm, but its many-to-many one-way transport is not appropriate for RPC request / reply interactions, which are often required in a distributed system. Request / reply is done via a Service, which is defined by a pair of messages: one for the request and one for the reply.

Parameter Server: A parameter server is a shared, multi-variate dictionary that is accessible via network APIs. Nodes use this server to store and retrieve parameters at runtime. As it is not designed for high-performance, it is best used for static, non-binary data such as configuration parameters.