I'm designing a piston that I need to expand a few cm in <100ms to load energy into a spring-mass system with around a pound of force (as shown below). Based on power specs alone, high-end hobby servos are light, strong and cheap enough for my needs: they simulate well when I'm able to push max voltage into them right away (i.e. operating them on the max torque-speed curve).
What I'm concerned about is the torque behavior in real-world servos. I'm interested in digital high-torque, high-frequency servos, typically used for steering in RC vehicles, that are either coreless or brushless. As a representative example, consider something like the Savox SV1272 or SB2274 (resp.), with refresh rates of 333Hz.
Is anyone aware if servos like this hold back on their power output with some kind of integrating control/loop delay in response to a step function? The tight timing of the stroke is what really concerns me: even if they wait for ~50ms I could lose most of the energy.
Looking around for clues, I've seen this comment here that links to this linearized position model of a Futaba servo as an example. This model is a PID controller in position rather than torque, so I imagine this is the response you get from operating below the torque-speed ceiling, while I really want to know the delta → torque behavior along that ceiling.