OPTIMIZING CONSUMPTION IN AGRICULTURAL MACHINES AND INSTALLATIONS BY USING DIGITAL HYDRAULICS

The proposed pieces of eguipment are: (1) a Digital Hydraulic Pumping System (DHPS) consisting of 4fixed flow pumps driven by a biaxial motor, 4 3/2 on/off electrohydraulic directional valves connected on the pump outlets, a 4/2 control valve, 4 one-way valves and a rotary hydraulic motor and (2) a Digital Flow Control Unit (DFCU) consisting of 5 electrohydraulic directional valves type 2/2, of different flow rates, connected to a fixed flow pump, connected to a hydraulic motor. According to Zang et al., (2020), the main features for digital systems are: = Active control of outputs. = Use of electrohydraulic directional valves on/off type. = Intelligent system control (use of microprocessors or PLCs). etc., or Fibonacci number is called Pulse Code Modulated (PCM). o Coding using series 1, 1, 1, etc. is called Pulse Number Modulated (PNM). = Hydraulic systems that use a single PWM operated electrohydraulic directional valve where the flow variation results from the sum of the open or closed periods. Figure 1 - If one electrohydraulic directional valve fails, the remaining valves are automatically reconfigured to produce a response curve that allows the machine to continue to run (***wpp_digihydraulics) The advantages of digital hydraulic systems are: = Due to the fact that digital systems use simple electrohydraulic directional valves that do not have high requirements on the working fluid, they increase the reliability of the system. = Using a programmable logic controller (PLC) and the fact that several components are used to adjust it, if one of them fails, the system will still be able to operate, even if not with the same high characteristics, as one can see in figure 1. = The acquisition cost is lower than other servo or propo systems.