Adapting move constraints for position based moves in a trajectory generator. Specification of a trajectory may be received. The specification may include a geometry of the trajectory, where the geometry specifies a desired trajectory length. A plurality of constraints for the trajectory may be received. The plurality of constraints may include one or more of a velocity, acceleration, or jerk constraint. A motion control profile may be generated based on the plurality of constraints. The method may include determining if a distance of the motion control profile exceeds the desired trajectory length. If the distance of the motion control profile exceeds the desired trajectory length, one or more values of the plurality of constraints may be decreased to make the distance of the motion control profile less than or equal to the desired trajectory length.