Hydrostatic fluid power actuators are versatile tools that have wide and varied applications to real-world engineering problems. Their high stiffness, haptic feedback, and force/displacement scaling can be harnessed to solve issues other actuators struggle with. This research presents the creation of two novel actuators and their applications: a piezo-hydraulic fast tool servo (FTS) and a Magnetic Resonance (MR) compatible actuator for remote robotic interventions. The FTS device, featuring motion amplification of the piezoelectric displacement, was designed and modeled, then fabricated and controlled to track a non-circular engine piston profile by Iterative Learning Control and Repetitive Control. The actuators for the MR robotic system---featuring back-drivable motion and force transmission over a significant distance---are designed, fabricated, and characterized to show many desirable properties. These actuators are the basis for a 1DOF stage for the emulation of respiratory motion in-bore, which was characterized, controlled, and shown to track recorded motion with acceptable error. These actuators were then used to realize co-robotic control of a 1DOF manipulator, demonstrating multiple modes of collaboration. Finally, a master-slave pair comprised part of a hardware-in-the-loop simulation of closed-loop control under MR image feedback using adaptive control. Results were analyzed to provide recommendations for a time when the full system, complete with image feedback, can be assembled.