Robo Explorer ROS Connector

Package Summary

This is a ROS Stack to control the fischertechnik Robo Explorer with ROS using liboboint.

• Author: Erik Andresen
• License: GNU GPL3

• Source: git clone https://github.com/nxdefiant/ros_roboint.git

You need to use the Robo Explorer with Wheels instead of Tracks because the Tracks are too inaccurate for Odometry. I used the Wheel Setup from Mobile Robots 2.

Tutorials

See https://github.com/nxdefiant/ros_roboint

Nodes

1. libft_adapter

libft_adapter accesses the Interface over libroboint.

1.1. Published Topics

ft/get_inputs - (bool[8] inputs, int8[8] outputs, AX, AY, A1, A2, AV, D1, D2 - all int16)

• Digital (Count from zero) and Analog Inputs of the Robo Interface. The current output states are included.

1.2. Subscribed Topics

ft/set_output - (num (int32), speed (int32))

• Individual Outputs of the Robo Interface (Count from zero)

ft/set_motor - (num (int32), speed (int32))

• Motor Outputs of the Robo Interface (Count from zero)

1.3. Parameters

2. robo_explorer.py

robo_explorer.py provides the Robo Explorer functions. Publishes ft/set_motor and subscribes to ft/get_inputs

2.1. Published Topics

scan - (sensor_msgs/LaserScan)

• Laserscan data faked by the Sonar Sensor.

odom - (nav_msgs/Odometry)

• Odometry information.

2.2. Subscribed Topics

cmd_vel - (geometry_msgs/Twist)

• Celocity commands.

2.3. Parameters

~ultrasonic_laser - (boolean, default: True)

• Fake laser scan with ultra sonic range finder.

~wheel_dist - (float, default: 0.1855)

• Distance between both wheels in meter.

~wheel_size - (float, default: 0.02575)

• Size of wheel Diameter in meter. Default: (5.15cm) * gear ratio (0.5) = 2.575cm

~speed_gradiant - (float, default: 64.3)

• Speed to PWM equation gradiant (The m in pwm = speed*m+b)

~speed_constant - (float, default: -1.7)

• Speed to PWM equation constant (The b in pwm = speed*m+b)