Hi Jack - Here's a couple of papers. Shapers are not a compete solution. They "solve" the mechanical vibration side of things in a simple way, they do not improve jerk, they are like a noise cancelling circuit. You have to identify the potential vibrations of the machine and address those with the cancelling circuit. It does not change the trajectory to improve jerk.

Once machines have accelerometers on the spindles (such as printers do) we can feed back the head accels and use jerk algorithms hand in hand with the shaper to solve it even better. Sophisticated machines have been doing this for some time. Peter

https://www.mdpi.com/1424-8220/22/6/2186