APM Planner 2.0.15 for keyboard command

My project needs me to control my copter on PC-terminal, which mainly based on keyboard way. What i want is letting GCS read the input stream from keyboard and Planner send the corresponding MAVLink command to the copter. I dont know how to get it and even dont know whether it is possible to reach it. Is there anyone who tried to do the same thing before? I need some advice.
Thank you.

Yes, we use an app like ControllerMate for MacOs that can map keyboard commands to a virtual joystick. Then you can control the autopilot using the joystick override feature.