Time-varying force tracking in impedance control a case study for automatic cell manipulation

Compared with the general compliance control problem where the manipulator-environment interaction force is often assumed to be a fixed value, a time-varying manipulation force of impedance control is studied upon a newly automatic cell injection system. The position-based impedance control method is deeply discussed, and two new controllers, a nonlinear PID controller for inner-loop position tracking and an adaptive impedance regulator for the outer force control loop, are well talked and introduced. Two conditions for time-varying force tracking in position-based impedance control are preliminarily given, and large amount of simulations are performed to verify the efficacy of the proposed methods in both trajectory and force control.