New control signal

[mich-pest]

Implementation of the new policy for controller-related message publication.

What changed?

Before a generic controller had to send ControlSignal message (encoding the torques) to the ControlLayer - that was responsible for sending DesiredTorques messages to the robot HAL - AND to send directly TrajectoryGenerator messages (encoding desired position and velocity, kp, kd) to HAL on different topics.

In the new structure ControlSignal has been modified as follows:

uint8 control_mode;
sequence<double> joints_position;
sequence<double> joints_velocity;
sequence<double> joints_torques;
sequence<double> kp;
sequence<double> kd;

With control_mode spanning the following supported modes:

• TORQUE_MODE
• IMPEDANCE_MODE
• POSITION_MODE
• VELOCITY_MODE

The generic controller publishes directly a ControlSignal message to the ControlLayer. Then the ControlLayer is responsible to publish a ControlSignal message read by the HAL.

More details in iit-DLSLab/dls2#334