Pressure-Based Force Control for Hydraulic Actuators with Proportional Flow Valves

Effective force tracking performance at the joint level is essential for robots to interact dynamically with their environment, responding to external influences while performing actions. Despite their utility, proportional flow hydraulic valves are limited by their inability to engage in reactive inverse correlation, thus reducing their effectiveness in these applications. In this paper, we explore strategies to overcome this limitation, such as the design and implementation of pressure-based controllers for force tracking, with an emphasis on analyzing the response time, intensity, and behavior of the hydraulic actuation system. In comparison to a force PID, we could reduce the steady-state error and the overshoot of the response by introducing an inner pressure control loop within the force control framework, enhancing its performance under realistic conditions and broadening the scope of potential applications.