Generate polynomial trajectories through waypoints

**Library:**Robotics System Toolbox / Utilities

The Polynomial Trajectory block generates trajectories to travel through
waypoints at the given time points using either cubic, quintic, or B-spline polynomials. The
block outputs positions, velocities, and accelerations for achieving this trajectory based on
the **Time** input. For B-spline polynomials, the waypoints actually define
the control points for the convex hull of the B-spline instead of the actual waypoints, but
the first and last waypoint are still met.

The initial and final values are held constant outside the time period defined in
**Time points**.

[1] Farin, Gerald E. *Curves
and Surfaces for Computer Aided Geometric Design: A Practical Guide*. San Diego,
CA: Academic Press, 1993.