This ROS package contains simple yet mandatory scripts to move a differential mobile robot.

The motor driver script uses 6 wire, 2 PWM mode to drive two motors through an H-bridge. It subscribes to two power motor topics:

rmotor_pwr_rob1
lmotor_pwr_rob1

The encoders script interfaces with quadrature encoders, calculates distances covered by each wheel and the velocities of each wheel

Distance are published on the topics:

rwheel_dist_rob1
lwheel_dist_rob1

Velocities are published on the topics:

rwheel_spd_rob1
lwheel_spd_rob1

The topics need to have a value from -100,100 as a duty cycle for the motor. The script handles the negative input as a reversing direction

It then transforms the twist message into required wheel velocities by using the base width as w in the beginning of the script The script subscribes to a twist message on the following topic

cmd_vel_rob1

The velocity pid script is a simple pid loop. When running, the output is published to the motor power topics, to which the motor driver is suscribed to. These are:

rmotor_pwr_rob1
lmotor_pwr_rob1

The script subscribes to the wheel velocities topics to run the pid algorithm:

rwheel_spd_rob1
lwheel_spd_rob1

The odometry script subscribes to wheel velocities and distances, and then publishes the current position of the robot on:

CurrentPosition_rob1