If you want to separate your motor's commands, you can :
- use one plugin and change the message type expected for command topic
- write a plugin that control only one motor. This plugin will be called for each of your motor.
- maybe look at ros_control
With the code that you have posted :
- maybe you can change the plugins name
(conflict between two plugins having
the same name)
- your command topic expected by these plugins should probably be : /labrob/motor1/cmd_vel and /labrob/motor2/cmd_vel