Hydraulic actuation systems are widely applied in the modern industry, such as robots, excavators, vehicle suspension systems, machine tools, and testing of structural systems, because hydraulic actuation systems are able to provide with large loading capacity. However, the design parameters and control techniques related to temperature, flow volume, flow resistance, etc., affect the stable performance of hydraulic pressure and need to be concerned with. In addition, while an unexpected external loading is applied, which makes a reaction force to the hydraulic oil and results in pressure variations, advanced real-time control techniques is required, in order to maintain a high-level stability and accuracy of the output pressure. To this end, a hydraulic power system is developed in this work, which installs two proportional valves for real-time adjustment of hydraulic pressure.
In this paper, the performance compensation of hydraulic pressure involves two steps of control development; the first step is to establish the mathematical model of the hydraulic adjustment system, and the second step is to simulate the pressure response of hydraulic adjustment system with controller design. In this first step, real-time dSPACE control system is utilized to implement identification work, for the purpose of establishing a multi-input/multi-output (MIMO) dynamic model of the active hydraulic adjustment system. Then, based on the dynamic model, the second step develops a feedforward-feedback and a PID controller for the active hydraulic adjustment system; the dynamic responses and control performance are verified via numerical simulation studies.
Seasonal patterns of grazing and nutrient limitation of phytoplankton in a eutrophic lake
