Hydraulic robot manipulators are essential for high-load collaborative tasks such as assembly and transport, offering powerful actuation and structural durability. However, their nonlinear dynamics and friction make precise, responsive control difficult during physical interaction with humans.
To address this, a custom 5-DOF hydraulic robot was designed with rotary actuators, electro-servo valves, joint encoders, and a force/torque sensor at the end-effector. A real-time controller based on compactRIO FPGA executes a discrete dynamic compensator that models the coupled leader-follower system as an equivalent mechanical structure. This enables real-time correction of unmodeled dynamics to improve motion tracking accuracy under unknown and varying loads.
Ongoing research focuses on extending this approach to handle hydraulic-specific effects such as internal friction, hysteresis, and actuation delays, aiming to enhance transparency and stability in interaction systems involving heavy-duty systems.
