Adaptive and Nonlinear Control of Discharge Pressure for Variable Displacement Axial Piston Pumps

2017 ◽  
Vol 139 (10) ◽  
Author(s):  
Janne Koivumäki ◽  
Jouni Mattila
Keyword(s):  
Controller Design ◽  
Design Method ◽  
Pressure Control ◽  
Feedback Signal ◽  
Hydraulic Systems ◽  
Axial Piston Pumps ◽  
Highly Nonlinear ◽  
Variable Displacement ◽  
Discharge Pressure ◽  
Axial Piston

This paper proposes, for the first time without using any linearization or order reduction, an adaptive and model-based discharge pressure control design for the variable displacement axial piston pumps (VDAPPs), whose dynamical behaviors are highly nonlinear and can be described by a fourth-order differential equation. The rigorous stability proof, with an asymptotic convergence, is given for the entire system. In the proposed novel controller design method, the specifically designed stabilizing terms constitute an essential core to cancel out all the stability-preventing terms. The experimental results reveal that rapid parameter adaptation significantly improves the feedback signal tracking precision compared to a known-parameter controller design. In the comparative experiments, the adaptive controller design demonstrates the state-of-the-art discharge pressure control performance, enabling a possibility for energy consumption reductions in hydraulic systems driven with VDAPP.

Leakage Based Condition Monitoring and Pressure Control of the Swashplate Axial Piston Pump

2019 ◽  
Author(s):  
Neeraj Kumar ◽  
Bikash Kumar Sarkar ◽  
Subhendu Maity
Keyword(s):  
Hydraulic System ◽  
Pressure Control ◽  
Piston Pump ◽  
Chamber Pressure ◽  
Leakage Flow ◽  
Axial Piston Pump ◽  
Highly Nonlinear ◽  
Displacement Pump ◽  
Variable Displacement ◽  
Axial Piston

Abstract This research mainly focused on the axial piston variable displacement pump, which is the most important part of the fluid power system. The variable displacement axial piston has been found as versatile and flexible for electro-hydraulic applications. Heavy industries such as automobile, aircraft, and mining use an axial piston pump due to its high power to weight ratio, continuous variable power transmission, low inertia, self-lubricating properties, and good controllability. The main challenges with the hydraulic system are highly nonlinear, leakages, unknown external disturbance, etc. The mathematical model of the variable displacement pump along with swashplate control has been developed. The model is used to identify the pump health condition with pressure and flow measurement, i.e., ripple pattern. The pressure and flow ripple will vary from the regular pattern due to wear and tear, i.e., increased leakage flow. The main source of the increase in leakage flow is due to wear in piston and cylinder bore. The piston chamber pressure, kinematical flow, and discharge area model of the pump has been validated with the existing results. The pump pressure control is very much essential for the enhancement of the performance of the electro-hydraulic system. In the present study, a conventional PID controller has been used as a backup to maintain system performance within the permissible faults. The electro-hydraulic system has been employed for swash-plate control of the pump to obtain desire pressure flow at the exit of the pump. MATLAB Simulink has been used for the simulation study of the pump.

scholarly journals A Methodology Based on Cyclostationary Analysis for Fault Detection of Hydraulic Axial Piston Pumps

Energies ◽  
2018 ◽  
Vol 11 (7) ◽  
pp. 1874 ◽  
Author(s):  
Paolo Casoli ◽  
Andrea Bedotti ◽  
Federico Campanini ◽  
Mirko Pastori
Keyword(s):  
Power Systems ◽  
Operating Conditions ◽  
Fault Identification ◽  
Hydraulic Systems ◽  
Axial Piston Pumps ◽  
Data Driven Approach ◽  
Variable Displacement ◽  
Fluid Power Systems ◽  
Axial Piston ◽  
Acceleration Signals

Condition monitoring has been an active area of research in many industrial fields during the last decades, particularly in fluid power systems. This paper presents a solution for the fault diagnosis of a variable displacement axial-piston pump, which is a critical component in many hydraulic systems. The proposed methodology follows a data-driven approach including data acquisition and feature extraction and is based on the analysis of acceleration signals through the theory of cyclostationarity. An experimental campaign was carried out on a laboratory test bench with the pump in the flawless state and in faulty states. Different operating conditions were considered and each test was repeated several times in order to acquire a suitable population to verify data repeatability. Results showed the capability of the proposed approach of detecting a typical fault related to worn slippers. Future works will include tests in order to apply the approach to a wider set of faults and the development of a classifier for accurate fault identification.

Characterization and Attenuation of Sandwiched Deadband Problem Using Describing Function Analysis and Its Application to Electro-Hydraulic Systems Controlled by Closed-Center Valves

2004 ◽  
Author(s):  
Song Liu ◽  
Bin Yao
Keyword(s):  
Closed Loop ◽  
Controller Design ◽  
Function Analysis ◽  
Nonlinear Behavior ◽  
Hydraulic Systems ◽  
Describing Function ◽  
Widespread Application ◽  
Actuator Dynamics ◽  
Loop Bandwidth ◽  
Highly Nonlinear

Sandwiched deadbands can be seen in a wide variety of systems, such as electro-hydraulic systems controlled by closed-center valves. In such a system, the deadband is between the plant and actuator dynamics and therefore can not be compensated directly like an input deadband. Though this sandwiched deadband problem may be attenuated to certain degree through sophisticated advanced control techniques, the increased cost and the necessity of actuator state feedback prohibit their widespread application in the industry. An economical and popular method is to add an inverse deadband function in the controller to cancel or compensate the highly nonlinear behavior of the deadband. However, such a solution requires that the dynamics before the deadband (eg. the valve dynamics) is fast enough to be neglected — a requirement that can not be met in reality unless the closed loop bandwidth of the overall system is limited very low. To raise the achievable closed loop bandwidth for a much improved control performance, it is essential to be able to precisely characterize the effect of this sandwiched deadband on the stability and performance of the overall closed-loop system, which is the main focus of the paper. Specifically, a describing function based nonlinear analysis will be conducted to predict when the instability will occur and how the resulting limit cycle depends on the actuator dynamics and the targeted closed-loop bandwidth. Based on the analysis, the optimal closed-loop bandwidth can be determined to maximize the achievable overall system performance. The technique is applied to an electro-hydraulic system controlled by closed-center valves to optimize the controller design.

Modelling a Variable Displacement Axial Piston Pump in a Multibody Simulation Environment

2006 ◽  
Vol 129 (4) ◽  
pp. 456-468 ◽  
Author(s):  
Alessandro Roccatello ◽  
Salvatore Mancò ◽  
Nicola Nervegna
Keyword(s):  
Power Systems ◽  
Three Dimensional ◽  
Fluid Power ◽  
Piston Pump ◽  
Axial Piston Pump ◽  
Axial Piston Pumps ◽  
Variable Displacement ◽  
Complex Fluid ◽  
Fluid Power Systems ◽  
Axial Piston

Analysis of a variable displacement axial piston pump, as in other complex fluid power and mechanical systems, requires appropriate insight into three multidisciplinary domains, i.e., hydraulics, mechanics and tribology. In recent years, at FPRL, modelling of axial piston pumps has evolved in AMESim (one-dimensional code) where a three-dimensional mechanical approach has required generation of proprietary libraries leading to the evaluation of internal forces/reactions in all pump subsystems. Tribologic aspects in axial piston pumps modelling are also being investigated but AMESim, in this respect, does not appear as the appropriate computational environment. Consequently, a new approach has been initiated grounded on MSC.ADAMS. In this perspective, the paper details how the model has been developed through proprietary macros that automatically originate all pump subsystems parametrically and further apply required constraints and forces (springs, contacts and pressure forces). The ADAMS environment has also been selected due to co-simulation capabilities with AMESim. Accordingly, the paper elucidates how the entire modelling has been construed where hydraulics is managed in AMESim while ADAMS takes care of mechanics. A comparison between simulated and experimental steady-state characteristics of the axial pump is also presented. As such this paper indicates an innovative methodology for the analysis of complex fluid power systems in the hope that, eventually, tribology will also fit into the scene.

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