Experimental Study on Fast and Energy-Efficient Direct Driven Hydraulic Actuator Unit

Abstract

In this experimental study, a Direct Driven Hydraulics (DDH) system of the closed circuit type was utilized for cyclic vertical actuation in heavy load material handling. The actuator was controlled by a speed-controlled fixed displacement pump. The high energy saving potential of this system has been demonstrated in previous studies by the authors, but the dynamic characteristics of the ramped and P-controlled base system were considered unsatisfactory. Therefore, the system was implemented with an open-loop S-curve control that utilized a pre-calculated RPM (revolutions per minute) profile for the electric motor in order to realize a smooth actuator and load transition as a function of time. The results indicate that S-curve control is exceptionally well suited for producing a controlled lifting–lowering rapid motion with a heavy load, while still keeping the actuator chamber pressures within acceptable limits. In comparison, the motion produced by P-control was characterized by large unwanted pressure peaks together with velocity fluctuations and vibrations at the end of the stroke. Using a combination of S-curve control and hydraulic load compensation, a mass of 1325 kg could be moved 0.26 m in less than 0.5 s. The load compensation reduced the energy consumption by 64%, which would allow downsizing the electric motor and enable cost-efficient DDH implementation.

A review on integral evolution of electro-hydraulic actuation in three momentous domains: aerospace, engineering machinery, and robotics

“…Moreover, the dynamic characteristics of the Ramp-controlled and P-controlled base system were considered unsatisfactory. Because of this, the performance and operational characteristics of the pump speed-controlled DDH system utilizing two different motion controllers: a Pcontroller and an S-controller is present in paper [52]. It can be seen that a combination of S-curve control and hydraulic load compensation can reduce energy consumption and achieve high efficiency by the ultimate endings.…”

Investigasi Lift Cylinder Rod Drift Pada Wheel Loader Wa 600-3a

“…Sebaliknya, perkembangan alat berat saat ini sangat berorientasi terhadap efisiensi energi, baik terhadap kerja sistem hidrolik maupun engine sebagai penggerak utama. Sistem hidrolik harus mampu meminimalisir kehilangan tenaga (efisien energi), serta akurat terhadap tekanan dan laju aliran dalam pergerakan actuator (rod cylinder) [4], [5]. Penggunaan fuel pada alat berat, berkaitan dengan tenaga engine yang dihasilkan juga harus efisien, dan rendah emisi [6,7,8].…”

Energy-saving strategies on power hydraulic system: An overview

“…The authors have derived the system dynamics and concluded that the new type of P FD EM VS -EHA system has a faster dynamical response in comparison to the traditional variable speed control hydraulic system. Also, Koitto et al 154 have presented an S-curve controller DDH system where the traditional piston position control scheme is replaced by the S-curve controller. But, still, this system has some other issues such as frequency bandwidth and stiffness that require appropriate solutions.…”