Development of an electrohydraulic actuator for agricultural equipment

The main actuators in most models of agricultural and special equipment are hydraulic linear motion drives, united by a common system of hydraulic lines and controlled by a valve system. Despite of many advantages of this solution, such a system has low positioning accuracy and energy efficiency. An alternative to hydraulic drives are electric actuators, which solve the disadvantages described above. However, the use of such actuators in the design of agricultural machinery is limited due to low resistance to shock overloads. The most promising type of drives are electrohydraulic actuators (EHA), which allow combining the advantages of these systems. The article describes the design of an EHA with a one-sided rod, its structural and fundamental hydrokinematic diagrams are given. Mathematical and simulation modeling of EHA is described. The structure and technical characteristics of the main component of the the developed motor driver EHA are presented separately. The results of laboratory tests of the control system for an electrohydraulic linear actuator and a prototype of the EHA on the Don-1500 combine produced by Rostselmash to regulate the position of the grain harvester deck are presented. As a result of tests of the EHA prototype, it was found that the developed actuator allows achieving high speeds of movement of working elements (up to 10 mm/s) and control and positioning accuracy (up to 0.25 mm), contains protection from impact loads, and also 2.2 times superior to electric drives of actuators used in agricultural machinery.