A Modeling and Simulation Method for Preliminary Design of an Electro-Variable Displacement Pump

Summary

A simulation model specifically supporting the preliminary design of an electro-variable displacement pump (EVDP) is developed and partially verified by experiments. The control performance, life, reliability, etc., can all be evaluated using the proposed model, which covers the main performance requirements under the EVDP preliminary design task.

Abstract

Electro-hydrostatic actuators (EHAs) have been considerably researched in academia, and their applications in various industrial fields are expanding. The variable-speed EHA has now taken priority over the variable-displacement EHA, but its driving motor and associated electronics encounter issues when applied in high-power applications: low-dynamics, high thermal dissipation, high price, etc. Therefore, a variable-displacement EHA equipped with an electro-variable displacement pump (EVDP) has been considered. The EVDP itself is a mechatronic system that integrates a piston pump, a ball screw, a gearbox, and a permanent magnet synchronous motor (PMSM). Consequently, the EVDP needs to be investigated to ensure its system-level performance when applied in an EHA. In addition to the previous research on the technical parameters of the EVDP, a dedicated design method is necessary for further reducing the cost of using the EVDP and exploring its performance potential. Here, a simulation based EVDP preliminary design method is selected for designing a 37 kW EVDP. Firstly, a previously proposed multidisciplinary model of the EVDP is extended by improving the parameter generation, including the EVDP life, reliability, control models, etc. Secondly, the proposed model is partially verified using a downsized prototype. Thirdly, the EVDP is simulated at a system level, supported by the proposed model. The EVDP performance is evaluated according to the specified design requirements. The temperature, bandwidth and accuracy, reliability and lifetime, etc., are all predicted for the EVDP. The simulation results demonstrate the EVDP's applicability in variable-displacement EHA. The proposed modeling and simulation method can be used to evaluate diverse EVDP performance and respond to general design requirements. The method can also support the resolution of the preliminary design challenges in terms of limited information and robustness. Therefore, the proposed method is appropriate for the realization of the simulation-based EVDP preliminary design method.

Introduction

Electro-hydrostatic actuators (EHAs) are receiving increasing interest for applications such as industrial presses, large mobile machinery, crane manipulators, and primary aircraft control due to their combination of the advantages of both electric actuators and hydraulic actuators¹. Two basic types of EHAs can be identified: variable-speed EHAs and variable-displacement EHAs². Currently, the variable-speed EHA is more popular than the variable-displacement EHA due to its higher efficiency and simplicity. However, along with the higher power level of the EHA, which is needed in heavy vehicles, such as heavy launch vehicl....

Protocol

NOTE: Matlab and Simcenter Amesim (referred to as system simulation platform hereafter) were used in this protocol and are listed in the Table of Materials. However, the proposed protocol is not limited to implementation in these two software applications.

1. Selecting and classifying the EVDP design parameters (Step 1 in Figure 2).

1. Dismantle the architecture of the EVDP in Figure 1 into a piston pump unit, a ball screw, a gearbox, a PMSM, and a controller. Check the performance requirements of the EVDP.
   NOTE: Part....

Results

This section presents the results obtained from performing all the protocol steps, which constitute part of Step 1, all of Step 2, and all of Step 5 of the EVDP preliminary design method in Figure 2. The input information in the protocol includes the EVDP schematics in Figure 1, the optimized active parameters (clarified in Step 5.1.1.) of the EVDP from Step 4 of Figure 2, and the EVDP performance simulation tasks, which relate to t.......

Discussion

The concept and other technical components of the EVDP have been presented in previous publications^6,31, demonstrating the applicability and advantages of the EVDP. Instead of studying the EVDP itself, this paper continued to study the design method in relation to future real application needs. A specific design method is necessary for this type of highly integrated and multidisciplinary coupling product, which calls for delicate performance trade-offs and optimi.......

Materials

List of materials used in this article

Name	Company	Catalog Number	Comments
Ball screw	NSK	PSS
EVDP prototype	Beijing Institute of Precision Mechatronics and Controls	customized	7.4 mL/rev, 7000 rpm, 21 Mpa
EVDP testrig	Beijing Institute of Precision Mechatronics and Controls	customized	Refer to Figure 7, can be adapted upon individual needs. Including Power PMAC controller, ELMO Whistle Driver, etc.
Gearhead	Maxon	GP
Matlab	Mathworks	R2020a
Permannet magnet synchronous motor	Maxon	393023
Piston pump	Bosch Rexroth	A10VZO
Simcenter Amesim	Siemens	2021.1	system simulation platform