Rolling and spinning friction example (demo_IRR_friction.cpp)

A benchmark that show the feature of spinning friction (aka 'drilling' friction) and rolling friction.

These types of frictions are useful for rolling objects like wheels, spheres etc. and can be optionally turned on.

This tutorial shows how to:

• enable rolling and spinning friction.
• impose initial velocity and angular velocity to objects.
  

// =============================================================================
// PROJECT CHRONO - http://projectchrono.org
//
// Copyright (c) 2014 projectchrono.org
// All rights reserved.
//
// Use of this source code is governed by a BSD-style license that can be found
// in the LICENSE file at the top level of the distribution and at
// http://projectchrono.org/license-chrono.txt.
//
// =============================================================================
// Authors: Alessandro Tasora
// =============================================================================
//
// Demo code about
// - using rolling friction (not only sliding and static friction, available in
//   all objects by default)
// - optional sharing of some assets (visualization stuff)
//
// =============================================================================
 
#include "chrono/physics/ChSystemNSC.h"
#include "chrono/physics/ChBodyEasy.h"
 
#include "chrono_irrlicht/ChIrrApp.h"
 
// Use the namespaces of Chrono
using namespace chrono;
using namespace chrono::irrlicht;
 
// Use the main namespaces of Irrlicht
using namespace irr;
using namespace irr::core;
using namespace irr::scene;
using namespace irr::video;
using namespace irr::io;
using namespace irr::gui;
 
 
int main(int argc, char* argv[]) {
    GetLog() << "Copyright (c) 2017 projectchrono.org\nChrono version: " << CHRONO_VERSION << "\n\n";
 
    // Create a ChronoENGINE physical system
    ChSystemNSC mphysicalSystem;
 
    // Create the Irrlicht visualization (open the Irrlicht device,
    // bind a simple user interface, etc. etc.)
    ChIrrApp application(&mphysicalSystem, L"Contacts with rolling friction", core::dimension2d<u32>(800, 600), false,
                         true);
 
    // Easy shortcuts to add camera, lights, logo and sky in Irrlicht scene:
    ChIrrWizard::add_typical_Logo(application.GetDevice());
    ChIrrWizard::add_typical_Sky(application.GetDevice());
    ChIrrWizard::add_typical_Lights(application.GetDevice());
    ChIrrWizard::add_typical_Camera(application.GetDevice(), core::vector3df(0, 14, -20));
 
 
    // Create all the rigid bodies.
 
    double mradius = 0.5;
    double density = 1000;
 
    // Create a texture asset. It can be shared between bodies.
    auto textureasset = chrono_types::make_shared<ChTexture>(GetChronoDataFile("bluwhite.png"));
 
    // Create some spheres that roll horizontally,
    // with increasing rolling friction values
    for (int bi = 0; bi < 10; bi++) {
        double initial_angspeed = 10;
        double initial_linspeed = initial_angspeed * mradius;
 
        auto msphereBody = chrono_types::make_shared<ChBodyEasySphere>(mradius,           // radius size
                                                              1000,              // density
                                                              true,              // collide enable?
                                                              true);             // visualization?
        // Set some properties
        msphereBody->SetPos(ChVector<>(-7, mradius - 0.5, -5 + bi * mradius * 2.5));
        msphereBody->GetMaterialSurfaceNSC()->SetFriction(0.4f);
        msphereBody->AddAsset(textureasset);  // assets can be shared
 
        // Set initial speed: rolling in horizontal direction,
        msphereBody->SetWvel_par(ChVector<>(0, 0, -initial_angspeed));
        msphereBody->SetPos_dt(ChVector<>(initial_linspeed, 0, 0));
 
        // Set a non zero value of rolling friction to have a rolling resisting torque:
        msphereBody->GetMaterialSurfaceNSC()->SetRollingFriction(((float)bi / 10) * 0.05f);
 
        // Add to the system
        mphysicalSystem.Add(msphereBody);
    }
 
    // Create some spheres that spin on place, for a 'drilling friction' case,
    // with increasing spinning friction values
    for (int bi = 0; bi < 10; bi++) {
        auto msphereBody = chrono_types::make_shared<ChBodyEasySphere>(mradius,           // radius size
            1000,              // density
            true,              // collide enable?
            true);             // visualization?
        // Set some properties
        msphereBody->SetPos(ChVector<>(-8, 1 + mradius - 0.5, -5 + bi * mradius * 2.5));
        msphereBody->GetMaterialSurfaceNSC()->SetFriction(0.4f);
        msphereBody->AddAsset(textureasset);  // assets can be shared
 
        // Set initial speed: spinning in vertical direction
        msphereBody->SetWvel_par(ChVector<>(0, 20, 0));
 
        // Set a non zero value of spinning friction that brakes the spinning on vertical axis
        // of the contact:
        msphereBody->GetMaterialSurfaceNSC()->SetSpinningFriction(((float)bi / 10) * 0.02f);
 
        // Add to the system
        mphysicalSystem.Add(msphereBody);
 
        // Notes:
        // - setting nonzero spinning friction and/or setting nonzero rolling friction
        //   affects the speed of the solver (each contact eats 2x of CPU time repsect to the
        //   case of simple sliding/staic contact)
        // - avoid using zero spinning friction with nonzero rolling friction.
    }
 
    // Create the five walls of the rectangular container, using
    // fixed rigid bodies of 'box' type:
 
    // floor:
 
    auto mfloorBody = chrono_types::make_shared<ChBodyEasyBox>(20, 1, 20,  // x,y,z size
                                                      2000,       // density
                                                      true,       // collide enable?
                                                      true);      // visualization?
    mfloorBody->SetPos(ChVector<>(0, -1, 0));
    mfloorBody->SetBodyFixed(true);
    mfloorBody->GetMaterialSurfaceNSC()->SetRollingFriction(
        1);  // the min. of the two coeff. of the two contact surfaces will be used
    mfloorBody->GetMaterialSurfaceNSC()->SetSpinningFriction(
        1);  // the min. of the two coeff. of the two contact surfaces will be used
 
    mfloorBody->AddAsset(chrono_types::make_shared<ChTexture>(GetChronoDataFile("blu.png")));
 
    mphysicalSystem.Add(mfloorBody);
 
    // four walls:
 
    auto mwallBody1 = chrono_types::make_shared<ChBodyEasyBox>(1, 2, 20.99,  // x,y,z size
        2000,         // density
        true,         // collide enable?
        true);       // visualization?
    mwallBody1->SetPos(ChVector<>(-10, 0, 0));
    mwallBody1->SetBodyFixed(true);
    mwallBody1->AddAsset(chrono_types::make_shared<ChColorAsset>(0.6f, 0.3f, 0.0f));
    mphysicalSystem.Add(mwallBody1);
 
    auto mwallBody2 = chrono_types::make_shared<ChBodyEasyBox>(1, 2, 20.99,  // x,y,z size
        2000,         // density
        true,         // collide enable?
        true);       // visualization?
    mwallBody2->SetPos(ChVector<>(10, 0, 0));
    mwallBody2->SetBodyFixed(true);
    mwallBody2->AddAsset(chrono_types::make_shared<ChColorAsset>(0.6f, 0.3f, 0.0f));
    mphysicalSystem.Add(mwallBody2);
 
    auto mwallBody3 = chrono_types::make_shared<ChBodyEasyBox>(20.99, 2, 1,  // x,y,z size
        2000,         // density
        true,         // collide enable?
        true);       // visualization?
    mwallBody3->SetPos(ChVector<>(0, 0, -10));
    mwallBody3->SetBodyFixed(true);
    mwallBody3->AddAsset(chrono_types::make_shared<ChColorAsset>(0.6f, 0.3f, 0.0f));
    mphysicalSystem.Add(mwallBody3);
 
    auto mwallBody4 = chrono_types::make_shared<ChBodyEasyBox>(20.99, 2, 1,  // x,y,z size
        2000,         // density
        true,         // collide enable?
        true);       // visualization?
    mwallBody4->SetPos(ChVector<>(0, 0, 10));
    mwallBody4->SetBodyFixed(true);
    mwallBody4->AddAsset(chrono_types::make_shared<ChColorAsset>(0.6f, 0.3f, 0.0f));
    mphysicalSystem.Add(mwallBody4);
 
 
    // Use this function for adding a ChIrrNodeAsset to all already created items.
    // Otherwise use application.AssetBind(myitem); on a per-item basis.
    application.AssetBindAll();
    application.AssetUpdateAll();
 
    // Modify some setting of the physical system for the simulation
    mphysicalSystem.SetSolverType(ChSolver::Type::APGD);
    mphysicalSystem.SetSolverMaxIterations(100);
 
    // Simulation loop
 
    application.SetStepManage(true);
    application.SetTimestep(0.01);
    application.SetTryRealtime(true);
 
    while (application.GetDevice()->run()) {
        application.BeginScene(true, true, SColor(255, 140, 161, 192));
 
        application.DrawAll();
 
        application.DoStep();
 
        application.EndScene();
    }
 
    return 0;
}