  Energy based control methods are at the core of modern robotic control
algorithms. In this paper we present a general approach to virtual
model/mechanism control, which is a powerful design tool to create energy based
controllers. We present two novel virtual-mechanisms designed for robotic
minimally invasive surgery, which control the position of a surgical instrument
while passing through an incision. To these virtual mechanisms we apply the
parameter tuning method of Larby and Forni 2022, which optimizes for local
performance while ensuring global stability.
