338-0506/04 – Hydraulic Mechanisms Control (Řízhy)
| Gurantor department | Department of Hydromechanics and Hydraulic Equipment | Credits | 5 |
| Subject guarantor | Ing. Adam Bureček, Ph.D. | Subject version guarantor | Ing. Adam Bureček, Ph.D. |
| Study level | undergraduate or graduate | Requirement | Compulsory |
| Year | 2 | Semester | winter |
| | Study language | Czech |
| Year of introduction | 2020/2021 | Year of cancellation | |
| Intended for the faculties | FS | Intended for study types | Follow-up Master |
Subject aims expressed by acquired skills and competences
Students will be acquainted with three qualitative grades of hydraulic mechanism control: classical control technique, proportional control technique, and servo technique. Students will learn to distinguish two basic methods of hydraulic mechanisms control: valve control and volumetric control. They are able to analyze both of these methods especially in terms of control accuracy, dynamic characteristics, energy performance, and price. In the case of proportional control are able to perform design the control system (synthesis) for a specific application. In the case of servomechanisms, they will be able to do the same for simpler applications.
Teaching methods
Lectures
Tutorials
Experimental work in labs
Project work
Summary
In the subject of Hydraulic Mechanisms Control, the students will learn about volumetric control and variable resistance control, dynamics of the controlled system, thermal balance of controlled hydrostatic drive and applications of control technique in hydrostatic mechanisms. Proportional control technique and servo technique are discussed in detail, where the knowledge of the subject of Fundamentals of Automation and Dynamics of Fluid Mechanisms is used. Students will learn the composition of speed and position servomechanisms. Furthermore, they will learn the principles of commissioning and maintenance of hydraulic proportional components and electrohydraulic servo valves and the issues of filtration of hydraulic devices with servo valves and proportional valves.
Compulsory literature:
[1] EWALD, R. et al. Proportional and Servo-valve Technology. Lohr am Main, Germany: Bosch Rexroth AG, 2003. 300 p.
[2] GÖTZ, W. Hydraulics. Theory and Applications. Ditzingen, Germany: OMEGON, 1998. 291 s. ISBN 3-980-5925-3-7.
Recommended literature:
Way of continuous check of knowledge in the course of semester
Credit: during the semester will be enter 4 programs for which it is possible to get up to 32 points. Minimum for obtaining credit is 20 points, max. 32 points.
Examination: oral exam - 2 questions, each for max 25 points, defense of programs for max. 18 points.
E-learning
The following study materials are available on the department website:
https://www.fs.vsb.cz/338/cs/studium/skripta/
Other requirements
Exam questions:
1. Variable resistance control (one-edge): control principle, static M-n, and F-v drive characteristics.
2. Pressure-dependent throttle valves. Throttle valves dependent and independent of viscosity. Throttle valves location at the inlet and outlet of the hydraulic motor.
3. Energy balance of variable resistance drive control.
4. Two-way flow control valves: function, construction, applications, energy balance.
5. Three-way flow control valves: function, construction, applications, energy balance.
6. Realization of constant pressure sources.
7. Proportional directional control valves (direct-actuated): construction, properties, applications. Types of spools. Flow Q-I characteristic.
8. Proportional directional control valves (pilot-actuated): construction, properties, applications.
9. Proportional pressure control valves. Proportional directional control valves with two-way and three-way flow control valve.
10. Selection of a suitable proportional directional control valve with respect to the system dynamics.
11. Volumetric drive control. Variable displacement pumps and methods of displacement control: mechanical, electrical, hydraulic direct-actuated and pilot-actuated, electrohydraulic.
12. Variable displacement pump with constant flow control. Hydraulic pump with LS regulation.
13. Servomechanisms: definitions, types, typical features, general block diagram. Example of copying machine.
14. Dynamic properties of servo drives: transfer properties of simple blocks.
15. Transient response, frequency response, magnitude and phase response of single blocks.
16. Servo valves: control spool, static characteristics, mathematical description.
17. Servo valves: 1st stage of servo valves, feedback types. Three-stage servo valves.
18. Servo valves: mathematical models of dynamic behavior. Dynamic characteristics.
19. Hydraulic motors of servo drives: construction, mathematical models of dynamic behavior.
20. Controllers, position and speed sensors.
21. Speed servomechanism: hydraulic diagram, control block diagram, properties, applications.
22. Positional servomechanism: hydraulic diagram, control block diagram, properties, applications.
23. Dynamic stability and methods of stabilization of positional servomechanisms.
24. Secondary control of hydraulic motors.
Prerequisities
Subject has no prerequisities.
Co-requisities
Subject has no co-requisities.
Subject syllabus:
Lectures
1. The definition of term control. Hydraulic mechanisms control: controlled variables, methods of control - classification. Variable resistance control (one-edge), which depends on the pressure drop on the motor. Sources of constant pressure.
2. Variable resistance control (one-edge), which is independent of the pressure drop on the motor. Two-way flow control valves. Viscosity-independent throttle valves. Three-way flow control valves.
3. Variable resistance control (two-edge). Four-edge control spool valve. Proportional directional control valves mechanically actuated.
4. Proportional directional control valves electrically actuated. The control electronics. Proportional directional control valves with two-way and three-way flow control valves, LS (load sensing) systems.
5. Design of hydraulic systems with proportional directional control valves.
6. Servo valves.
7. Servo drives. Application of servo drives in aviation, robotics, machine tools, thermal and nuclear power engineering.
8. Dynamics of servo drives. Methods of the description of control circuit components, mathematical-physical models of control circuit components.
9. Rotary servo drives: mathematical description of dynamic behavior, control methods, dynamic stability.
10. Positional servomechanisms with mechanical feedback. Electro-hydraulic positional servomechanisms. Mathematical description of dynamic behavior, control methods, dynamic stability.
11. Stabilization of positional servomechanisms.
12. Volumetric control.
13. Secondary control of hydraulic motors. Pressure, force, torque control.
14. Principles of assembly, operation, and maintenance of servomechanisms. Filtration and temperature stabilization.
Contents of exercises and seminars
1. Repetition of basic terms of fluid mechanisms.
2. Variable resistance control: hydraulic systems with throttle valves.
3. Variable resistance control: hydraulic systems with two-way and three-way flow control valves.
4. Program 1: Measurement of throttle valve characteristics. Measurement of two-way flow control valve characteristics.
5. Program 2: Measurement of the torque M dependence on the speed n of the drive with variable resistance control.
6. Program 3: Design of hydraulic circuit with proportional directional control valve. Example from the metallurgical industry.
7. Design of hydraulic circuit with proportional directional control valve - completion.
8. Design of hydrostatic transmission with volumetric control of the pump and the hydraulic motor.
9. Transient response, transfer functions, frequency response.
10. Mathematical-physical models of hydraulic components of control hydraulic system.
11. Program 4: Design of rotary servo drive. An example of the lifting equipment.
12. Measurement of rotary servo drive - to program No.4.
13. Design of positional servomechanism. An example from the field of nuclear energy engineering.
14. Demonstration of positional servomechanism in the laboratory. Credit.
Conditions for subject completion
Occurrence in study plans
Occurrence in special blocks
Assessment of instruction