Generic Modeling and Control of an Open-Circuit Piston Pump—Part II: Control Strategies and Designs

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Shu Wang
Keyword(s):  
State Space ◽  
Control Strategies ◽  
State Space Model ◽  
Control Valve ◽  
Open Circuit ◽  
The State ◽  
Operating Conditions ◽  
Torque Control ◽  
Space Representation ◽  
Load Pressure

Hydromechanical compensators are often integrated with piston-type pumps to produce various control behavior, for example, pressure, load-sensing, power, or torque control. Various hydromechanical mechanisms (e.g., spring forces and load pressure) are found in the industry to ensure the desired effect of the system outputs: swash angle, discharge pressure, and input torque following the reference inputs. In a companion paper (Part I of this paper), a generic linearized state-space model is derived to investigate the pump dynamics and determine the design criteria and parameters. In the study, the state-space equations are used to propose and define the generic compensating control pump to conduct the similar strategies as hydromechanical pumps do. The different control purposes (pressure/flow/power compensating) are accomplished by only manipulating the generic regulate inputs given by an electrical proportional control valve. In the open-circuit pump, the generic controllers are proposed to generate these inputs by using one unique mechanical and electronic architecture to establish various purposes of flow, pressure, torque desired control, and even more control objectives. The controller is developed in accordance with the state-space representation and by following the models of the hydromechanical compensators that can facilitate the correlation verification. The proposed controllers are able to offer more intelligent and cost-saving control strategies for open-circuit piston pumps. To achieve the similar performance as hydromechanical compensators do and implement the comparative study, control gains and settings in the controller can be determined from ones that hydromechanical compensators have. The difference is that electronic signals (swash plate position, pressure, etc.) work as feedbacks together with other control gains to regulate the input signals. For the different control purposes, control gains are able to be set conveniently for the various control operating conditions with combining the certain feedbacks on the same hardware platform that will be value efficient and capable of control intelligence. In the paper, results of predictions made by the model are presented and compared with some experimental data of hydromechanical designs. Further work on the advanced model-based control and estimation is anticipated to be addressed.

Optimal State-Space Control of a Gas Turbine Engine

1992 ◽  
Vol 114 (4) ◽  
pp. 763-767 ◽  
Author(s):  
J. W. Watts ◽  
T. E. Dwan ◽  
C. G. Brockus
Keyword(s):  
State Space ◽  
Gas Turbine ◽  
State Space Model ◽  
Gas Turbine Engine ◽  
The State ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Analog Control ◽  
Linear State ◽  
High Level

An analog fuel control for a gas turbine engine was compared with several state-space derived fuel controls. A single-spool, simple cycle gas turbine engine was modeled using ACSL (high level simulation language based on FORTRAN). The model included an analog fuel control representative of existing commercial fuel controls. The ACSL model was stripped of nonessential states to produce an eight-state linear state-space model of the engine. The A, B, and C matrices, derived from rated operating conditions, were used to obtain feedback control gains by the following methods: (1) state feedback; (2) LQR theory; (3) Bellman method; and (4) polygonal search. An off-load transient followed by an on-load transient was run for each of these fuel controls. The transient curves obtained were used to compare the state-space fuel controls with the analog fuel control. The state-space fuel controls did better than the analog control.

Optimal State Space Control of a Gas Turbine Engine

1991 ◽  
Author(s):  
J. W. Watts ◽  
T. E. Dwan ◽  
C. G. Brockus
Keyword(s):  
State Space ◽  
Gas Turbine ◽  
State Space Model ◽  
Gas Turbine Engine ◽  
The State ◽  
Operating Conditions ◽  
Turbine Engine ◽  
Analog Control ◽  
Linear State ◽  
High Level

An analog fuel control for a gas turbine engine was compared with several state space derived fuel controls. A single spool, simple cycle gas turbine engine was modeled using ACSL (high level simulation language based on FORTRAN). The model included an analog fuel control representative of existing commercial fuel controls. The ACSL model was stripped of non-essential states to produce an 8 state linear state space model of the engine. The A, B, and C matrices, derived from rated operating conditions, were used to obtain feedback control gains by the following methods: (1) state feedback; (2) LQR theory; (3) Bellman method; and (4) polygonal search. An off-load transient followed by an on-load transient was run for each of these fuel controls. The transient curves obtained were used to compare the state space fuel controls with the analog fuel control. The state space fuel controls did better than the analog control.

Generic Modeling and Control of an Open-Circuit Piston Pump—Part I: Theoretical Model and Analysis

2016 ◽  
Vol 138 (4) ◽  
Author(s):  
Shu Wang
Keyword(s):  
Control Strategies ◽  
State Space Model ◽  
Open Circuit ◽  
Operating Conditions ◽  
Piston Pump ◽  
Generic Model ◽  
Parameter Uncertainties ◽  
Pump Design ◽  
Swash Plate ◽  
Proposed Model

Since variable-displacement open-circuits piston pumps are equipped with diverse compensators or controllers, many different modeling approaches and representations have been developed in the previous research. In the industry, the type of pump design (with an offset between the driving shaft and rotating center of the swash plate to neutralize the swash plate which replaces the bias piston) becomes more popular to reduce manufacturing costs that will be addressed in the research. To facilitate designs of electrohydraulic (EH) controllers and comparison studies of performance, the study proposes a generic state-space model of piston pumps acting in an open-circuit configuration by using generic regulator and unique reference inputs. One major contribution of the work is typical control strategies (including the pressure control, load-sensing control, and power control) in open-circuits pumps, which are described in one generic model. Thus, the model can be expediently used for investigations and improving piston pump designs. Even more important, the model can contribute as a unique and efficient plant to apply various model-based EH control that will be more convenient, intelligent, and less cost than current designs in the industry. Also, most previous modeling work of open-circuit piston pumps only concerns the steady-state results of the pump dynamics to simply the calculations that may ignore some important dynamics. The proposed model considers the high-order dynamics of the pump, such as swash plate velocity and accelerations. The variations caused by these terms are embedded in the model coefficients and regarded as the parameter uncertainties so that the model can take advantage of both modeling linearization and transient dynamics. It is highly challenging to analyze the stability and controllability issues during the design of piston pumps because they are impacted by many nonlinear parameters and operating conditions. So, the study presents another important methodology to analyze and define the critical design specification, such as stability, controllability, and observability. In the proposed model, the dynamical characteristics can be examined and compared by pumping subsystems and overall system in a single consistent platform. The controller gain scheduling and design performance are also able to assessed and determined while defining and specifying design criteria of the pump itself.

An investigation into a state space model for an attenuator in automotive hydraulic systems

2003 ◽  
Vol 217 (1) ◽  
pp. 63-67 ◽  
Author(s):  
J-C Lee
Keyword(s):  
State Space ◽  
Time Domain ◽  
State Space Model ◽  
The State ◽  
Dynamic Responses ◽  
Space Representation ◽  
Response Analysis ◽  
Space Model ◽  
Electrical Analogy ◽  
The Time Domain

A hydraulic attenuator has been used in hydraulic active suspension systems of automotive vehicles to reduce high amplitude ripple pressure of a pump. The hydraulic attenuator considered in this study is so highly non-linear and of high order that the analysis in the time domain has been performed infrequently, although the frequency response analysis with the transfer matrix method was applicable. In this paper, a state space representation of the dynamics for a hydraulic attenuator is presented, utilizing the electrical analogy. The results of the experiment are compared with those of the simulation to validate the state space model proposed. The comparison reveals that the state space model proposed is practically applicable for estimating the dynamic responses of the hydraulic attenuator in the time domain.

Dynamic Analysis of a Torsional MEMS Scanner Mirror: Part 1 — Disturbance Analysis Framework

2005 ◽  
Author(s):  
Faik Can Meral ◽  
Ipek Basdogan
Keyword(s):  
State Space ◽  
Transfer Functions ◽  
State Space Model ◽  
Time Domain Analysis ◽  
The State ◽  
Space Representation ◽  
Modeling And Analysis ◽  
Lyapunov Approach ◽  
State Space Representation ◽  
Disturbance Analysis

Future optical micro systems such as Micro Electro Mechanical Systems (MEMS) scanners and micro-mirrors will extend the resolution and sensitivity offered by their predecessors. These systems face the challenge of achieving nanometer precision subjected to various disturbances. Predicting the performance of such systems early in the design process can significantly impact the design cost and also improve the quality of the design. Our approach aims to predict the performance of such systems under various disturbance sources and develop a generalized design approach for MEMS structures. In this study, we used ANSYS for modeling and analysis of a torsional MEMS scanner mirror. ANSYS modal analysis results, which are eigenvalues (natural frequencies) and eigenvectors (modeshapes), are used to obtain the state space representation of the mirror. The state space model of the scanner mirror was reduced using various reduction techniques to eliminate the states that are insignificant for the transfer functions of interest. The results of these techniques were compared to obtain the best approach to obtain a lower order model that still contains all of the relevant dynamics of the original model. After the model size is reduced significantly, a disturbance analysis is performed using Lyapunov approach to obtain root-mean-square (RMS) values of the mirror rotation angle under the effect of a disturbance torque. The Lyapunov approach results were validated using a time domain analysis.

Design Methodology for Microelectromechanical Systems. Case Study: Torsional Scanner Mirror

2006 ◽  
Vol 129 (10) ◽  
pp. 1023-1030 ◽  
Author(s):  
Faik Can Meral ◽  
Ipek Basdogan
Keyword(s):  
State Space ◽  
Microelectromechanical Systems ◽  
Transfer Functions ◽  
State Space Model ◽  
The State ◽  
Mode Shapes ◽  
Design Parameters ◽  
Space Representation ◽  
Disturbance Analysis ◽  
Disturbance Torque

Future optical microsystems, such as microelectromechanical system (MEMS) scanners and micromirrors, will extend the resolution and sensitivity offered by their predecessors. These systems face the challenge of achieving nanometer precision subjected to various disturbances. Predicting the performance of such systems early in the design process can significantly impact the design cost and also improve the quality of the design. Our approach aims to predict the performance of such systems under various disturbance sources and develop a generalized design approach for MEMS structures. In this study, we used ANSYS for modeling and dynamic analysis of a torsional MEMS scanner mirror. ANSYS modal analysis results, which are eigenvalues (natural frequencies) and eigenvectors (mode shapes), are used to obtain the state-space representation of the mirror. The state-space model of the scanner mirror was reduced using various reduction techniques to eliminate the states that are insignificant for the transfer functions of interest. The results of these techniques were compared to obtain the best approach to obtain a lower order model that still contains all the relevant dynamics of the original model. After the model size is reduced significantly, a disturbance analysis is performed using Lyapunov approach to obtain root-mean-square values of the mirror rotation angle under the effect of a disturbance torque. The magnitude levels of the disturbance torque are obtained using an experimental procedure. The disturbance analysis framework is combined with the sensitivity analysis to determine the critical design parameters for optimizing the system performance.

Modeling of CCLP in koryo extract production

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Ji Chol ◽  
Ri Jun Il
Keyword(s):  
Process Control ◽  
Medical Care ◽  
State Space ◽  
State Space Model ◽  
The State ◽  
Space Model ◽  
Effective Components ◽  
Counter Current

Abstract The modeling of counter-current leaching plant (CCLP) in Koryo Extract Production is presented in this paper. Koryo medicine is a natural physic to be used for a diet and the medical care. The counter-current leaching method is mainly used for producing Koryo medicine. The purpose of the modeling in the previous works is to indicate the concentration distributions, and not to describe the model for the process control. In literature, there are no nearly the papers for modeling CCLP and especially not the presence of papers that have described the issue for extracting the effective components from the Koryo medicinal materials. First, this paper presents that CCLP can be shown like the equivalent process consisting of two tanks, where there is a shaking apparatus, respectively. It allows leachate to flow between two tanks. Then, this paper presents the principle model for CCLP and the state space model on based it. The accuracy of the model has been verified from experiments made at CCLP in the Koryo Extract Production at the Gang Gyi Koryo Manufacture Factory.

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