why do we need the (pid) controllers in ros_control?
For example, I have a robot with a motor controlled by a embeded board and I want to use ros applications to control the robot. Usually, there is a pid , let's say, speed controller implemented in the embeded board(or in the driver of motor). The SBC send(write) speed control signals to the embeded board. So I believe all we need is a hardware interface to translate ros msgs to embeded's control signal. what is the point of controllers in ros_control? Can I only implement a hardware interface and how?