1 // =============================================================================
2 // PROJECT CHRONO - http://projectchrono.org
3 //
4 // Copyright (c) 2014 projectchrono.org
5 // All rights reserved.
6 //
7 // Use of this source code is governed by a BSD-style license that can be found
8 // in the LICENSE file at the top level of the distribution and at
9 // http://projectchrono.org/license-chrono.txt.
10 //
11 // =============================================================================
12 // Authors: Alessandro Tasora
13 // =============================================================================
14 //
15 // Demo code about
16 // - using IRRLICHT as a realtime 3D viewer of a four-bar mechanism
17 // - using the IRRLICHT graphical user interface (GUI) to handle user-input
18 // via mouse.
19 //
20 // =============================================================================
21
22 #include "chrono/physics/ChLinkMotorRotationSpeed.h"
23 #include "chrono/physics/ChSystemNSC.h"
24
25 #include "chrono_irrlicht/ChIrrApp.h"
26
27 // Use the namespaces of Chrono
28 using namespace chrono;
29 using namespace chrono::irrlicht;
30
31 // Use the main namespaces of Irrlicht
32 using namespace irr;
33 using namespace irr::core;
34 using namespace irr::scene;
35 using namespace irr::video;
36 using namespace irr::io;
37 using namespace irr::gui;
38
39 // Some static data (this is a simple application, we can do this ;) just to allow easy GUI manipulation
40 IGUIStaticText* text_motorspeed = 0;
41
42 // The MyEventReceiver class will be used to manage input
43 // from the GUI graphical user interface (the interface will
44 // be created with the basic -yet flexible- platform
45 // independent toolset of Irrlicht).
46
47 class MyEventReceiver : public IEventReceiver {
48 public:
MyEventReceiver(ChSystemNSC * system,IrrlichtDevice * device,std::shared_ptr<ChLinkMotorRotationSpeed> motor)49 MyEventReceiver(ChSystemNSC* system, IrrlichtDevice* device, std::shared_ptr<ChLinkMotorRotationSpeed> motor) {
50 // store pointer to physical system & other stuff so we can tweak them by user keyboard
51 msystem = system;
52 mdevice = device;
53 mmotor = motor;
54 }
55
OnEvent(const SEvent & event)56 bool OnEvent(const SEvent& event) {
57 // check if user moved the sliders with mouse..
58 if (event.EventType == EET_GUI_EVENT) {
59 s32 id = event.GUIEvent.Caller->getID();
60
61 switch (event.GUIEvent.EventType) {
62 case EGET_SCROLL_BAR_CHANGED:
63 if (id == 101) // id of 'motor speed' slider..
64 {
65 s32 pos = ((IGUIScrollBar*)event.GUIEvent.Caller)->getPos();
66 double newspeed = 10 * (double)pos / 100.0;
67 // set the speed into motor object
68 if (auto mfun = std::dynamic_pointer_cast<ChFunction_Const>(mmotor->GetSpeedFunction()))
69 mfun->Set_yconst(newspeed);
70 // show speed as formatted text in interface screen
71 char message[50];
72 sprintf(message, "Motor speed: %g [rad/s]", newspeed);
73 text_motorspeed->setText(core::stringw(message).c_str());
74 }
75 break;
76 default:
77 break;
78 }
79 }
80
81 return false;
82 }
83
84 private:
85 ChSystemNSC* msystem;
86 IrrlichtDevice* mdevice;
87 std::shared_ptr<ChLinkMotorRotationSpeed> mmotor;
88 };
89
main(int argc,char * argv[])90 int main(int argc, char* argv[]) {
91 GetLog() << "Copyright (c) 2017 projectchrono.org\nChrono version: " << CHRONO_VERSION << "\n\n";
92
93 // 1- Create a Chrono physical system
94 ChSystemNSC my_system;
95
96 // Create the Irrlicht visualization (open the Irrlicht device,
97 // bind a simple user interface, etc. etc.)
98 ChIrrApp application(&my_system, L"Example of integration of Chrono and Irrlicht, with GUI",
99 core::dimension2d<u32>(800, 600));
100
101 // Easy shortcuts to add camera, lights, logo and sky in Irrlicht scene:
102 application.AddTypicalLogo();
103 application.AddTypicalSky();
104 application.AddTypicalLights();
105 application.AddTypicalCamera();
106
107 // 2- Create the rigid bodies of the four-bar mechanical system
108 // (a flywheel, a rod, a rocker, a truss), maybe setting
109 // position/mass/inertias of their center of mass (COG) etc.
110
111 // ..the truss
112 auto my_body_A = chrono_types::make_shared<ChBody>();
113 my_system.AddBody(my_body_A);
114 my_body_A->SetBodyFixed(true); // truss does not move!
115
116 // ..the flywheel
117 auto my_body_B = chrono_types::make_shared<ChBody>();
118 my_system.AddBody(my_body_B);
119 my_body_B->SetPos(ChVector<>(0, 0, 0)); // position of COG of flywheel
120
121 // ..the rod
122 auto my_body_C = chrono_types::make_shared<ChBody>();
123 my_system.AddBody(my_body_C);
124 my_body_C->SetPos(ChVector<>(4, 0, 0)); // position of COG of rod
125
126 // ..the rocker
127 auto my_body_D = chrono_types::make_shared<ChBody>();
128 my_system.AddBody(my_body_D);
129 my_body_D->SetPos(ChVector<>(8, -4, 0)); // position of COG of rod
130
131 // 3- Create constraints: the mechanical joints between the
132 // rigid bodies. Doesn't matter if some constraints are redundant.
133
134 // .. a motor between flywheel and truss
135 auto my_link_AB = chrono_types::make_shared<ChLinkMotorRotationSpeed>();
136 my_link_AB->Initialize(my_body_A, my_body_B, ChFrame<>(ChVector<>(0, 0, 0)));
137 my_system.AddLink(my_link_AB);
138 auto my_speed_function = chrono_types::make_shared<ChFunction_Const>(CH_C_PI); // speed w=3.145 rad/sec
139 my_link_AB->SetSpeedFunction(my_speed_function);
140
141 // .. a revolute joint between flywheel and rod
142 auto my_link_BC = chrono_types::make_shared<ChLinkLockRevolute>();
143 my_link_BC->Initialize(my_body_B, my_body_C, ChCoordsys<>(ChVector<>(2, 0, 0)));
144 my_system.AddLink(my_link_BC);
145
146 // .. a revolute joint between rod and rocker
147 auto my_link_CD = chrono_types::make_shared<ChLinkLockRevolute>();
148 my_link_CD->Initialize(my_body_C, my_body_D, ChCoordsys<>(ChVector<>(8, 0, 0)));
149 my_system.AddLink(my_link_CD);
150
151 // .. a revolute joint between rocker and truss
152 auto my_link_DA = chrono_types::make_shared<ChLinkLockRevolute>();
153 my_link_DA->Initialize(my_body_D, my_body_A, ChCoordsys<>(ChVector<>(8, -8, 0)));
154 my_system.AddLink(my_link_DA);
155
156 //
157 // Prepare some graphical-user-interface (GUI) items to show
158 // on the screen
159 //
160
161 // ..add a GUI text and GUI slider to control motor of mechanism via mouse
162 text_motorspeed =
163 application.GetIGUIEnvironment()->addStaticText(L"Motor speed:", rect<s32>(300, 85, 400, 100), false);
164 IGUIScrollBar* scrollbar =
165 application.GetIGUIEnvironment()->addScrollBar(true, rect<s32>(300, 105, 450, 120), 0, 101);
166 scrollbar->setMax(100);
167
168 // ..Finally create the event receiver, for handling all the GUI (user will use
169 // buttons/sliders to modify parameters)
170 MyEventReceiver receiver(&my_system, application.GetDevice(), my_link_AB);
171 // note how to add the custom event receiver to the default interface:
172 application.SetUserEventReceiver(&receiver);
173
174 //
175 // Configure the solver with non-default settings
176 //
177
178 // By default, the solver uses the EULER_IMPLICIT_LINEARIZED stepper, that is very fast,
179 // but may allow some geometric error in constraints (because it is based on constraint
180 // stabilization). Alternatively, the timestepper EULER_IMPLICIT_PROJECTED is slower,
181 // but it is based on constraint projection, so gaps in constraints are less noticeable
182 // (hence avoids the 'spongy' behaviour of the default stepper, which operates only
183 // on speed-impulse level and keeps constraints'closed' by a continuous stabilization).
184 my_system.SetTimestepperType(ChTimestepper::Type::EULER_IMPLICIT_LINEARIZED);
185
186 //
187 // THE SOFT-REAL-TIME CYCLE, SHOWING THE SIMULATION
188 //
189
190 // use this array of points to store trajectory of a rod-point
191 std::vector<chrono::ChVector<> > mtrajectory;
192
193 application.SetTimestep(0.001);
194
195 while (application.GetDevice()->run()) {
196 application.BeginScene();
197
198 // This will draw 3D assets, but in this basic case we will draw some lines later..
199 application.DrawAll();
200
201 // .. draw a grid
202 tools::drawGrid(application.GetVideoDriver(), 0.5, 0.5);
203 // .. draw a circle representing flywheel
204 tools::drawCircle(application.GetVideoDriver(), 2.1, ChCoordsys<>(ChVector<>(0, 0, 0), QUNIT));
205 // .. draw a small circle representing joint BC
206 tools::drawCircle(application.GetVideoDriver(), 0.06,
207 ChCoordsys<>(my_link_BC->GetMarker1()->GetAbsCoord().pos, QUNIT));
208 // .. draw a small circle representing joint CD
209 tools::drawCircle(application.GetVideoDriver(), 0.06,
210 ChCoordsys<>(my_link_CD->GetMarker1()->GetAbsCoord().pos, QUNIT));
211 // .. draw a small circle representing joint DA
212 tools::drawCircle(application.GetVideoDriver(), 0.06,
213 ChCoordsys<>(my_link_DA->GetMarker1()->GetAbsCoord().pos, QUNIT));
214 // .. draw the rod (from joint BC to joint CD)
215 tools::drawSegment(application.GetVideoDriver(), my_link_BC->GetMarker1()->GetAbsCoord().pos,
216 my_link_CD->GetMarker1()->GetAbsCoord().pos, video::SColor(255, 0, 255, 0));
217 // .. draw the rocker (from joint CD to joint DA)
218 tools::drawSegment(application.GetVideoDriver(), my_link_CD->GetMarker1()->GetAbsCoord().pos,
219 my_link_DA->GetMarker1()->GetAbsCoord().pos, video::SColor(255, 255, 0, 0));
220 // .. draw the trajectory of the rod-point
221 tools::drawPolyline(application.GetVideoDriver(), mtrajectory, video::SColor(255, 0, 150, 0));
222
223 // HERE CHRONO INTEGRATION IS PERFORMED: THE
224 // TIME OF THE SIMULATION ADVANCES FOR A SINGLE
225 // STEP:
226 // my_system.DoStepDynamics(0.01);
227
228 // We need to add another point to the array of 3d
229 // points describing the trajectory to be drawn..
230 mtrajectory.push_back(my_body_C->Point_Body2World(ChVector<>(1, 1, 0)));
231 // keep only last 150 points..
232 if (mtrajectory.size() > 150)
233 mtrajectory.erase(mtrajectory.begin());
234
235 // THIS PERFORMS THE TIMESTEP INTEGRATION!!!
236 application.DoStep();
237
238 application.EndScene();
239 }
240
241 return 0;
242 }
243