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emros-em5
emros-em5

emros overview

Last edited by Christian Sponfeldner
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EMROS an Overview

The EMROS software is based on the ROS (Robot Operating System) open-source platform, which was developed for robotics applications. It enables to control Nanotec's "drive and technology platform RP-NTH-2D01-C1-Sx-Px" from ROS.

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The key tasks of the EMROS software are:

  • The conversion of ROS topic cmd_vel (travel commands that are sent by your higher-level ROS system) into movements of the motors of Nanotec's "drive and technology platform RP-NTH-2D01-C1-Sx-Px"
  • Providing the odometry data to your higher-level ROS system under the topic odom. The odometry data is an estimate of the position based on the actual movements of the vehicle.
  • The interaction with the powerboard of RP-NTH (display and forwarding of the data, e.g., of the battery status) The following figure shows the general design of the drive and technology platform:

image

Part of the software, EMROS-ROS, runs on your on-board computer with Linux and is responsible for calculating the necessary drive speeds. EMROS-ROS sends the target values for the individual wheel drives to the EMROS-EM5 part of the software via Ethernet (using a simple self defined UDP based protocoll named "EtherProtocol").

EMROS-EM5 is the software within the freely programmable part of the EM5 CANopen master. Because ROS (ROS 1) is not currently real-time capable, the EM5 controls the drives in a temporally precise cycle via CANopen.

The drives (CANopen slaves) receive the target values (target velocity) via CANopen and perform the movements. Their current data (actual velocity) is processed by EMROS-EM5 and sent to EMROS-ROS. The following figure shows the communication sequence between the components of the system:
image