example.cc

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#include <cmath>

#include <towr/towr.h>
#include <towr/models/centroidal_model.h>


using namespace towr;


// Generate even ground.
class FlatGround : public HeightMap {
public:
  virtual double GetHeight(double x, double y) const override { return 0.0; };
};


// The kinematic limits of a one-legged hopper
class MonopedKinematicModel : public KinematicModel {
public:
  MonopedKinematicModel () : KinematicModel(1)
  {
    nominal_stance_.at(0) = Eigen::Vector3d( 0.0, 0.0, -0.58);
    max_dev_from_nominal_ << 0.25, 0.15, 0.2;
  }
};


// The Centroidal dynamics of a one-legged hopper
class MonopedDynamicModel : public CentroidalModel {
public:
  MonopedDynamicModel()
  : CentroidalModel(20,                              // mass of the robot
                    1.2, 5.5, 6.0, 0.0, -0.2, -0.01, // base inertia
                    1) {}                            // number of endeffectors
};


int main()
{
  // Kinematic limits and dynamic parameters of the hopper
  RobotModel model;
  model.dynamic_model_   = std::make_shared<MonopedDynamicModel>();
  model.kinematic_model_ = std::make_shared<MonopedKinematicModel>();


  // set the initial position of the hopper
  BaseState initial_base;
  initial_base.lin.at(kPos).z() = 0.5;
  Eigen::Vector3d initial_foot_pos_W = Eigen::Vector3d::Zero();


  // define the desired goal state of the hopper
  BaseState goal;
  goal.lin.at(towr::kPos) << 1.0, 0.0, 0.5;


  // Parameters that define the motion. See c'tor for default values or
  // other values that can be modified.
  Parameters params;
  params.t_total_ = 1.6; // [s] time to reach goal state
  // here we define the initial phase durations, that can however be changed
  // by the optimizer. The number of swing and stance phases however is fixed.
  // alternating stance and swing:     ____-----_____-----_____-----_____
  params.ee_phase_durations_.push_back({0.4, 0.2, 0.4, 0.2, 0.4, 0.2, 0.2});
  params.ee_in_contact_at_start_.push_back(true);


  // Pass this information to the actual solver
  TOWR towr;
  towr.SetInitialState(initial_base, {initial_foot_pos_W});
  towr.SetParameters(goal, params, model, std::make_shared<FlatGround>());

  towr.SolveNLP();
  auto x = towr.GetSolution();


  // Print out the trajecetory at discrete time samples
  using namespace std;
  cout.precision(2);
  cout << fixed;
  cout << "\n====================\nMonoped trajectory:\n====================\n";

  double t = 0.0;
  while (t<=params.t_total_+1e-5) {

    cout << "t=" << t << "\n";
    cout << "Base linear position x,y,z:   \t";
    cout << x.base_linear_->GetPoint(t).p().transpose()     << "\t[m]" << endl;

    cout << "Base Euler roll, pitch, yaw:  \t";
    Eigen::Vector3d rad = x.base_angular_->GetPoint(t).p();
    cout << (rad/M_PI*180).transpose()                      << "\t[deg]" << endl;

    cout << "Foot position x,y,z:          \t";
    cout << x.ee_motion_.at(0)->GetPoint(t).p().transpose() << "\t[m]" << endl;

    cout << "Contact force x,y,z:          \t";
    cout << x.ee_force_.at(0)->GetPoint(t).p().transpose()  << "\t[N]" << endl;

    bool contact = x.phase_durations_.at(0)->IsContactPhase(t);
    std::string foot_in_contact = contact? "yes" : "no";
    cout << "Foot in contact:              \t" + foot_in_contact << endl;

    cout << endl;

    t += 0.2;
  }
}