Robust two-degrees-of-freedom control of hydraulic drive with remote wireless operation

In this paper, a controller design targeting the remotely operated hydraulic drive system is presented. A two-degrees-of-freedom PID position controller is used, which is designed so that to maximize the integral action under robust constraint. A linearized model of the system plant, affected by the parameters uncertainties such as variable communication time-delay and overall system gain, is formulated and serves for the control design and analysis. The performed control synthesis and evaluation are targeting the remote operation where the wireless communication channel cannot secure a deterministic real-time of the control loop. The provided analysis of uncertainties makes it possible to ensure system stability under proper conditions. The theoretically expected results are confirmed through laboratory experiments on the standard industrial hydraulic components.