Hydraulic Servo-systems: Modelling, Identification and Control

'1 Introduction.- 1.1 Historical View and Motivation for Hydraulic Systems.- 1.2 Aims and Focus of the Book.- 1.3 Outline of the Chapters.- 1.4 Background of the Work and Bibliographical Notes.- 2 General Description of Hydraulic Servo-systems.- 2.1 Basic Structure of Hydraulic Servo-systems.- 2.2 Description of the Components.- 2.2.1 Valves.- 2.2.2 Pumps and Actuators.- 2.2.3 Power Supplies.- 2.3 Classification of Hydraulic Servo-systems.- 2.4 Measurement and Control Devices.- 2.4.1 Control Loops.- 2.4.2 Sensors/Transducers.- 2.5 Application Examples.- 2.5.1 Hydraulically Actuated Manipulators.- 2.5.2 Hydraulic Automatic Gauge Control for Rolling Mills.- 3 Physical Fundamentals of Hydraulics.- 3.1 Physical Properties of Fluids.- 3.1.1 Viscosity and Related Quantities.- 3.1.2 Mass Density, Bulk Modulus and Related Quantities.- 3.1.3 Effective Bulk Modulus.- 3.1.4 Section Summary.- 3.2 General Equations of Fluid Motion.- 3.2.1 Continuity Equation and Pressure Transients.- 3.2.2 Navier-Stokes Equation.- 3.2.3 Bernoulli's Theorem.- 3.2.4 Section Summary.- 3.3 Flow Through Passages.- 3.3.1 Flow Establishment in Pipelines.- 3.3.2 Flow Through Orifices.- 3.3.3 Flow Through Valves.- 3.3.4 Section Summary.- 3.4 Spool Port Forces.- 3.5 Electro-hydraulic Analogy.- 3.5.1 Hydraulic Capacitance.- 3.5.2 Hydraulic Resistance.- 3.5.3 Hydraulic Inductance.- 4 Physically Based Modelling.- 4.1 Introduction.- 4.1.1 Characterisation of Subsystems.- 4.1.2 Model Complexity and Applications.- 4.2 Elementary Models.- 4.2.1 Valves.- 4.2.2 Hydraulic Cylinders.- 4.2.3 Hydraulic Pumps and Motors.- 4.2.4 Power Supplies.- 4.2.5 Pipelines.- 4.3 Typical Non-linear State-space Models.- 4.4 Structured and Simplified Models of Valve-controlled Systems.- 4.4.1 Relevance of Valve and Pipeline Dynamics.- 4.4.2 Approximation of Pressure Dynamics.- 4.4.3 Introduction of Load Pressure.- 4.4.4 Linearised Models.- 4.5 Determination of Specific Model Parameters.- 4.5.1 Static Valve Characteristics.- 4.5.2 Dynamic Valve Characteristics.- 4.5.3 Actuator Dimensions and Mass.- 4.5.4 Friction Forces.- 4.5.5 Leakage Coefficients and Valve Underlap.- 4.6 Implementation and Software Tools.- 4.6.1 Simulation of Frietion Forces.- 4.6.2 Simulation of Mechanical Saturations.- 4.6.3 Simulation Packages.- 4.7 Section Summary.- 5 Experimental Modelling (Identification).- 5.1 Introduction.- 5.1.1 Generic Identification Procedure.- 5.1.2 Linear vs. Non-linear Identification.- 5.1.3 Online vs. Offline Identification.- 5.2 Pre-identification Process.- 5.2.1 Design of Input Signals.- 5.2.2 Pre-computations.- 5.3 Overview of Model Structures.- 5.3.1 Introductory Remarks and Definitions.- 5.3.2 Review of Linear Model Structures.- 5.3.3 Non-linear Input-output Models.- 5.3.4 Non-linear State-space Models.- 5.4 Description of Selected Non-linear Model Structures.- 5.4.1 Continuous-time Special (Canonical) Models.- 5.4.2 Fuzzy Models.- 5.4.3 Artificial Neural Networks.- 5.5 Parameter Estimation Methods.- 5.5.1 Prediction Error Methods.- 5.5.2 Classical Least-squares Analysis.- 5.5.3 Orthogonal Least-squares Estimator.- 5.5.4 Maximum Likelihood Method.- 5.5.5 Bias/Nariance Dilemma and Regularisation Concepts.- 5.6 Optimisation Algorithms.- 5.6.1 Newton's Method.- 5.6.2 Damped Gauss-Newton Method.- 5.6.3 Levenberg-Marquardt Algorithrn.- 5.6.4 Computational Aspects.- 5.7 Grey-box Identification ofNon-linear Hydraulic Servo-system Models.- 5.7.1 Identification of Pressure Dynamics Model.- 5.7.2 Identification of Load Dynamics Model.- 5.7.3 Online Identification for Adaptive Control.- 5.7.4 Identification of General Models.- 5.8 Fuzzy Identification.- 5.8.1 Introduction and Model Parameter Overview.- 5.8.2 Structure Identification.- 5.8.3 Parameter Identification (Premise).- 5.8.4 Parameter Identification (Conclusion).- 5.8.5 Optimisation.- 5.9 Identification with Artificial Neural Networks.- 5.9.1 Sele