Editing Trajectory planner

Trajectory planner in GD drives is an internal function to produce smooth acceleration and velocity trajectories based on user input, that may be just a rapid [[setpoint]] value change. The main purpose of trajectory planner is to allow creating simple point-to-point motion with minimal complexity from the [[controller]].

==Operation==
Trajectory planner has two main parameters which define the motion profile limits:
*{{param|CVL}}
*{{param|CAL}}

Following example illustrates a case where user setpoint changes instantly, and causes trajectory planner to generate acceleration & velocity limited motion.
{{picturebox|Trajectory planner.svg|caption=Signal change inside Trajectory planner}}

Trajectory planner has no limit of how often setpoint may be changed. It is possible to give new setpoint even when motion has not reached it's target position, and output motion still follows the given speed limits.

==Application==
===When to use===
Trajectory planner is mostly used in following cases:
*Point-to-point positon control
*Velocity control (such as spindle)
*Velocity limiting for safety reasons on all position & velocity control mode applications
===When to avoid===
As trajectory planner causes limited rate of change, it is not desirable in applications that demand high bandwidth position or velocity control such as:
*[[Dual-loop feedback position control]], or any system where setpoint of drive is output of another closed loop system
*Systems where external motion controller takes care of acceleration limit calculation and trajectory generation

To prevent trajectory planner from distorting or causing lag in such systems, it can be effectively disabled by setting {{param|CAL}} to maximum value. Velocity limit may be still used for safety reasons as it will not alter the signal unless setpoint velocity exceeds the {{param|CVL}} limit.

==See also==
*[[Signal path of motor drive]]