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adams液压系统仿真

Overview

Welcome to ADAMS/Hydraulics. ADAMS/Hydraulics is a plugin to ADAMS/View, ADAMS/Solver, ADAMS/Car, and ADAMS/Engine. ADAMS/Hydraulics is a plugin to ADAMS/View, ADAMS/Solver,

ADAMS/Car, and ADAMS/Engine. It lets you model and simulate fluid-powered circuits and control how the circuits interact with mechanical models. ADAMS/Hydraulics contains all of the hydraulic components you need to model your hydraulic circuits: valves, pumps, cylinders, and so on. The components take advantage of the parameterization and function capabilities of

ADAMS/View and ADAMS/Solver. The result is a powerful open environment for complete modeling of complex hydraulic-driven mechanisms and systems.

■Introducing ADAMS/Hydraulics 3

■Introducing the Problem 5

■Creating a Hydraulic Circuit 11

■Testing Your Model 39

The information in this document is furnished for informational use only, may be revised from time to time, and should not be construed as a commitment by MSC.Software Corporation. MSC.Software Corporation assumes no responsibility or liability for any errors or inaccuracies that may appear in this document.

This document contains proprietary and copyrighted information. MSC.Software Corporation permits licensees of MSC.ADAMS? software products to print out or copy this document or portions thereof solely for internal use in connection with the licensed software. No part of this document may be copied for any other purpose or distributed or translated into any other language without the prior written permission of MSC.Software Corporation.

Trademarks

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NASTRAN is a registered trademark of the National Aeronautics Space Administration. MSC.Nastran is an enhanced proprietary version developed and maintained by MSC.Software Corporation. All other trademarks are the property of their respective owners.

Government Use

Use, duplication, or disclosure by the U.S. Government is subject to restrictions as set forth in FAR 12.212 (Commercial Computer Software) and DFARS 227.7202 (Commercial Computer Software and Commercial Computer Software Documentation), as applicable.

Overview

This chapter introduces you to ADAMS/Hydraulics and explains how you can benefit from using it.

This chapter contains the following sections:

■What This Guide Assumes, 4

■Getting Help Online, 4

What This Guide Assumes

This guides assumes the following:

■You have working knowledge of ADAMS/View and ADAMS/Solver (knowledge of hydraulic theory is helpful, but not required).

■ADAMS/Hydraulics is installed on your computer or network, your path variable contains the location where ADAMS/Hydraulics is installed, and

you have permission to execute ADAMS/Hydraulics.

If you do not know if ADAMS/Hydraulics is installed or where it is located,

see your local ADAMS/Hydraulics expert or system administrator.

■You can read in the standard model provided with this tutorial and run through a basic simulation of the model without the hydraulics added.

Getting Help Online

When working in ADAMS/Hydraulics, you can get help as follows:■From the Help menu, select ADAMS/Hydraulics Help.

■While working in any dialog box, press the F1 key.

Overview

This tutorial teaches you how to use ADAMS/Hydraulics to perform a design study of a mechanism combined with a hydraulic circuit. The design study will find the proper counter-balance valve pilot area ratio to maximize the stability of the boom on a construction backhoe.

In this tutorial you will build the hydraulic circuit, combine the circuit with a mechanical model, test the system through static and dynamic analyses, parameterize the counter-balance valve, and run a design study.

This chapter provides details about the model you will use, and the problem you will address. It includes the following sections:

■The Problem Statement, 6

■What You Will Learn, 6

■What You Will Create and Analyze, 8

This part of the tutorial takes about 90 minutes to

complete.

The Problem Statement

For construction equipment, faster and smoother operating equipment can mean much lower construction costs. The problem in this tutorial is to design a hydraulic circuit to drive a lift mechanism for a construction backhoe. You will also determine the proper counter-balance valve pilot area ratio for maximum stability.

What You Will Learn

The tutorial leads you through the design process steps outlined in Figure1 on page 7. These are the basic steps you should follow whenever you use ADAMS/Hydraulics to build and test models:

■Step 1 - Build: Create hydraulic components and junction elements to connect the circuit. Connect components and junction elements into a

complete circuit.

■Step 2 - Test: Run static and dynamic analyses to determine settling point, transient response, and performance.

■Step 3 - Review: Examine flow rates and achievable cylinder velocity. Run static and dynamic analyses to determine the transient response of slow

movement. Examine the cylinder velocity and counter-balance valve spool

movement.

■Step 4 - Improve: Parameterize components for a design study. Run a design study.

Figure 1. Design Process Steps for the Excavator Model

Build

◆Create the components for the hydraulic circuit

◆

Create junction elements to connect the circuit

◆Connect the components and junction elements into a complete circuit

◆

Connect the hydraulic cylinder to the boom mechanism of the backhoe

Validate

Test Improve

Review

◆

Run a static analysis to determine the combined hydraulic/mechanical settling point

◆

Run a dynamic analysis to determine the transient response and performance of the system

◆Examine the valve flow rates ◆

Examine the cylinder velocity

◆

Parameterize the counter-balance pilot valve area ratio for a design study

◆

Run a design study to determine the best area ratio for stability

What You Will Create and Analyze

In this tutorial, you build a hydraulic circuit that duplicates the interaction between the hydraulics and the mechanics of an excavator model, as shown in Figure 2. The hydraulic circuit, shown in Figure3 on page 9, models a pump and control valve circuit to regulate the force applied on a hydraulic cylinder within the excavator model. The control valve is adjusted by a control function, which actuates the valve and causes the excavator model to perform as intended. The stability of the excavator model is most affected by the counter-balance valve. The counter-balance valve characteristics affect the speed of response of the overall system. Once you build the circuit and connect it to the mechanism, you run a simple design study to explore the effects of the counter-balance valve pilot area ratio on the smoothness of cylinder motion.

Figure 2. Excavator Model

Hydraulic circuit defines the force

applied by this actuator.

Figure 3. Hydraulic Circuit as Modeled in ADAMS

A Tank (tank)

Pressure source (pressure_source)

Directional control valve

(dcv43)

Counter balance valve

(cbv)

Cylinder (cyl2)

(jctn1)

Junction1(jctn2)Junction2(jctn3)

Junction3A

A B

B A

C X

B T P

Check valve (cv)

Overview

This chapter teaches you how to start working with

ADAMS/Hydraulics, and how to create and connect hydraulic components to each other and to a mechanical system. Note:We recommend that you refer to the guide,

ADAMS/Hydraulics Component Reference as you go

through this tutorial.

This chapter includes the following sections:

■Starting ADAMS/View and Importing your Model, 12

■Running Preliminary Analyses, 15

■Creating the Hydraulic Components, 19

■Connecting the Hydraulic Components, 35

Starting ADAMS/View and Importing your Model

In this section, you learn how to start ADAM/Hydraulics from within ADAMS/View in the UNIX and Windows environments. You will also set up your ADAMS/View environment.

Because ADAMS/Hydraulics is a plugin for ADAMS/View, ADAMS/Car, ADAMS/Rail, and ADAMS/Engine, you need to load ADAMS/Hydraulics when you use ADAMS/Hydraulics with any of these products.

In the UNIX environment, you start ADAMS/View from the MSC.ADAMS Toolbar, and then load the ADAMS/Hydraulics plugin. For information on the MSC.ADAMS Toolbar, see the guide, Running and Configuring MSC.ADAMS on UNIX.

In the Windows environment, you start ADAMS/View from the Start menu, and then load the ADAMS/Hydraulics plugin. For more information, see the guide, Running MSC.ADAMS on Windows.

To start MSC.ADAMS and import your model:

1Create a working directory, and copy the contents of

install_dir/hydraulics/examples/excavator/ to that directory (where install_dir is the directory where ADAMS/Hydraulics is installed).

1Do either of the following depending on the platform on which you are running ADAMS/View:

■In UNIX, type the command to start the MSC.ADAMS Toolbar at the

command prompt, and then press Enter. Select the ADAMS/View tool .

■In Windows, from the Start menu, point to Programs, point to

MSC.Software, point to MSC.ADAMS 2003, point to AView, and then select

ADAMS - View.

The Welcome dialog box appears, in the ADAMS/View main window.

2Select Import a file.

3Select the Find Directory tool next to the Start in text box. This displays the Find Directory dialog box.

Note:The Start in text box specifies the working directory that

ADAMS/Hydraulics uses as the default directory for reading and

writing files.

4Navigate to the working directory that you created in step 1.

5Select OK.

This ensures that all your work gets stored in the working directory.

6Select OK.

The File Import dialog box appears.

7Right-click the File to Read text box, and select Browse.

8Select excavator.cmd.

9Select OK.

ADAMS/View opens the excavator model and displays it.

Note that the model units are kiloNewtons, kilograms, meters, and seconds. To set up the ADAMS/View environment:

1If they’re not already on, turn on the visibility of icons.

2Set the orientation view of the model so that your vantage point is from the right, along the global x-axis.

Your ADAMS/View environment should look like the one in Figure4 on page

14.

Figure 4. Right View with Initial Settings

Running Preliminary Analyses

Before creating a hydraulic circuit for the excavator, you’ll use a motion to drive the mechanism and gather some baseline results.

First you add motion and a measure to the mechanical system, and then you run an analysis to see what the force requirements are for the motion. Later, you deactivate the motion and design a hydraulic circuit to generate the required force levels to duplicate the motion results.

Next you run a preliminary static and a dynamic analysis, and then plot the results. To add a motion:

■Create a translational motion on JOINT_D (see Figure5 on page 16).

■Change motion type to velocity.

■Define the motion function as: step (time, 0.0, 0.0, 0.4, -0.3).

■Rename the motion lift_motion.

Figure 5. Locations of JOINT_C and JOINT_D

JOINT_C (revolute)

JOINT_D (translational)

To create a measure:

1Create a measure on motion_force.

2Name the measure lift_force.

3Set Characteristic to force.

4Set Component to mag.

5Set From/At to boom_cylrod.D.

6Select OK.

To run the analyses:

1Run a static analysis.

2Run a 1.0-second, 50-step dynamic analysis.

To plot the results:

1From the Review menu, select Postprocessing.

ADAMS/Hydraulics launches ADAMS/PostProcessor, a post-processing tool that lets you view the results of a simulation. Take a minute to familiarize

yourself with ADAMS/PostProcessor.

Figure6 on page 18 shows a conceptual sketch of the ADAMS/PostProcessor window.

Figure 6. ADAMS/PostProcessor Window

2From the dashboard, set Source to Objects .3From the Filter list, select constraint .4From the Object list, select lift_motion .

5From the Characteristic list, select Element _Force .6From the Component list, select Mag .7

Select Add Curves .

The plot shows a static force magnitude level of approximately 66 kN and a peak level of 107 kN.

8Return to the ADAMS/Hydraulics main window.

To deactivate the motion:1Right-click lift_motion .2Select (De)activate .

Clear the selection of Object Active .

Menu bar

4Clear the selection of Object’s Dependents Active.

5Select OK.

6Close the strip chart for lift_force.

Creating the Hydraulic Components

The hydraulic circuit you build in this tutorial consists of several components: ■fluid

■tank

■pressure source

■directional control valve

■counter-balance valve

■check valve

■three three-port junctions

■two-way cylinder

Figure3 on page 9 shows the components that you will create. You later connect the components into a circuit and connect the circuit to the mechanical system.

Once you’ve created the hydraulic circuit, you can analyze the combined mechanical and hydraulic systems with static, linear, and dynamic simulations.

You must create the fluid first because it is used for all other components. You can create the other components in any order, but for this tutorial, we recommend that you create them in the order presented.

Note:To drag an object in ADAMS/Hydraulics, you must press the Ctrl and Shift keys simultaneously while holding down the left mouse button.

You create the hydraulic components as described in the following sections:■Loading ADAMS/Hydraulics and Checking Defaults, 20

■Loading ADAMS/Hydraulics and Checking Defaults, 20

■Setting Up the Working Grid, 23

■Creating the Fluid, 25

■Creating the Tank, 26

■Creating the Pressure Source, 27

■Creating the Directional Control Valve 4/3, 28

■Creating the Counter-Balance Valve, 29

■Creating the Check Valve, 30

■Creating the Cylinder, 31

■Creating Junctions, 33

Loading ADAMS/Hydraulics and Checking Defaults

In this section, you will load ADAMS/Hydraulics and check the defaults for the program.

To load ADAMS/Hydraulics and check defaults:

1From the Tools menu, point to Plugin Manager.

2Select the Load checkbox next to ADAMS/Hydraulics.

3Select OK.

ADAMS/View loads the ADAMS/Hydraulics plugin. If you receive an error message, you might have a problem with your licensing. Contact your system administrator or local MSC.ADAMS expert.

Note:To automatically load ADAMS/Hydraulics each time ADAMS/View starts up, select the Load at Startup checkbox.