Project 2: Fluid Machinery/Fluid Power Engineering and Control
Title: Design and Analysis of an excavator for industrial applications
Submission date: Week 12 (pl. see Moodle site)
A hydraulic fluid power system manages large industrial works easily
For industrial applications, an excavator operates on huge concrete pipes, digs large strong soil at construction sites. The excavator is one of the good examples of industrial machines used hydraulic cylinders. There are a few cylinders used for controlling the operations of the excavator (Figure 1). As a fluid power design engineer to design such a system, you have to determine the load on each cylinder for a given position carrying out proper force analysis of the system. For an accurate analysis, the information of weight to be carried and centre of gravity of the boom, stick and bucket system (Figure 1) may be needed.
Figure 1 presents a conventional fluid power hydraulic excavator system. The purpose of this design is to carry a huge concrete pipe load of 100kN. In the excavator system, observe that there are four hydraulic cylinders used to drive three pin-connected members: boom, stick and bucket (Figure 1). The detailed connection information of boom, stick and bucket can be found in the literature (Espositio, 2014, p. 218).
Figure 1: A hydraulic excavator system (Esposito, 2014)
For better analysis, drawing hydraulic circuits is the key to studying fluid power system such as hydraulic excavators. Simulation of a hydraulic circuit in Matlab is a good way to study and analyse the hydraulic circuits you design. In Matlab, you have to use Simulink, SimScape (SimScape Fluid). You have to go to Fluids, then Hydraulics (isothermal). From the library menu, you can draw the circuit. This menu has various components needed to construct a fluid circuit diagram. By choosing the right components, the hydraulic symbols are assembled for analysis.
The aim of this project is to exercise your theoretical knowledge of fluid power systems in excavator operations for practical applications in mechanical engineering using Simscape/SimScape Fluid in Simulink (Matlab).
You are required to study, analyse and assess an existing conventional hydraulic excavator systems considering information available (you can assume some reasonable necessary data). Then design a new hydraulic excavator system or modify the existing design that has better performance. This is a team submission and each team must present their findings in week 12 workshop session.
Your submission should have the following items and headings:
(1) Introduction to fluid power systems relating to hydraulic excavator systems
(2) Literature review on Conventional hydraulic excavator systems using standard papers from journals, conferences, books and reports
(3) Working principles of existing hydraulic excavator systems.
(4) Develop a case based on your research and develop a set of assumptions for your proposed design (maximum load can be about 100kN for example)
(5) Design and analysis of a new or modified hydraulic excavator system capable of safe load carrying capacity that gives better control: flow control, pressure control and directional control using sufficient minimum controlling devices and valves
(6) Safety check of pipes and pressure cylinders (thick-walled or thin-walled analysis)
(7) Prepare an Excel calculation sheet to input data, standard equations, creating plots to compare
(8) Health and safety practices required for maintaining the system.
(9) Use proper drafting tools to show changes in your new design.
(10) Draw necessary hydraulic fluid circuit diagrams
(11) Apply SimScape/SimScape Fluid and carry out analysis of your new design: piston positions, velocity, flow rate etc. vs time.
(12) Prepare team report and submit on time and present the results by presentation of materials
Your report must include executive summary, scope and objectives, methodology, schematic diagrams where necessary, results and discussions and concluding remarks and references in the Harvard system.
4. Submission: It is a team submission. Due date is Friday midnight, week 12
5. Presentation: It is team presentation during workshop time (dress code – not casual). For distance student teams, pl. send a recording (You-tube) in week 12.
6. Reference: Fluid Power with applications, A. Esposito, 2014.