friction_cone.hpp

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#ifndef ROBOTOC_FRICTION_CONE_HPP_
#define ROBOTOC_FRICTION_CONE_HPP_
 
#include "Eigen/Core"
 
#include "robotoc/robot/robot.hpp"
#include "robotoc/robot/contact_status.hpp"
#include "robotoc/core/split_solution.hpp"
#include "robotoc/core/split_direction.hpp"
#include "robotoc/core/split_kkt_residual.hpp"
#include "robotoc/core/split_kkt_matrix.hpp"
#include "robotoc/constraints/constraint_component_base.hpp"
#include "robotoc/constraints/constraint_component_data.hpp"
 
 
namespace robotoc {
 
class FrictionCone final : public ConstraintComponentBase {
public:
  using Vector5d = Eigen::Matrix<double, 5, 1>;
 
  FrictionCone(const Robot& robot);
 
  FrictionCone();
 
  ~FrictionCone();
 
  FrictionCone(const FrictionCone&) = default;
 
  FrictionCone& operator=(const FrictionCone&) = default;
 
  FrictionCone(FrictionCone&&) noexcept = default;
 
  FrictionCone& operator=(FrictionCone&&) noexcept = default;
 
  KinematicsLevel kinematicsLevel() const override;
 
  void allocateExtraData(ConstraintComponentData& data) const override;
 
  bool isFeasible(Robot& robot, const ContactStatus& contact_status, 
                  ConstraintComponentData& data, 
                  const SplitSolution& s) const override;
 
  void setSlack(Robot& robot, const ContactStatus& contact_status, 
                ConstraintComponentData& data, 
                const SplitSolution& s) const override;
 
  void evalConstraint(Robot& robot, const ContactStatus& contact_status, 
                      ConstraintComponentData& data, 
                      const SplitSolution& s) const override;
 
  void evalDerivatives(Robot& robot, const ContactStatus& contact_status, 
                       ConstraintComponentData& data, const SplitSolution& s,
                       SplitKKTResidual& kkt_residual) const override;
 
  void condenseSlackAndDual(const ContactStatus& contact_status, 
                            ConstraintComponentData& data, 
                            SplitKKTMatrix& kkt_matrix,
                            SplitKKTResidual& kkt_residual) const override;
 
  void expandSlackAndDual(const ContactStatus& contact_status, 
                          ConstraintComponentData& data, 
                          const SplitDirection& d) const override; 
 
  int dimc() const override;
 
  template <typename VectorType1, typename VectorType2>
  static void frictionConeResidual(const double mu, 
                                   const Eigen::MatrixBase<VectorType1>& f_world,
                                   const Eigen::Matrix3d& R_surface,
                                   const Eigen::MatrixBase<VectorType2>& res) {
    assert(mu > 0);
    assert(f_world.size() == 3);
    assert((R_surface*R_surface.transpose()).isIdentity());
    assert(res.size() == 5);
    const Eigen::Vector3d f_local = R_surface.transpose() * f_world;
    const_cast<Eigen::MatrixBase<VectorType2>&>(res).coeffRef(0) = - f_local.coeff(2);
    const_cast<Eigen::MatrixBase<VectorType2>&>(res).coeffRef(1) 
        = f_local.coeff(0) - mu * f_local.coeff(2) / std::sqrt(2);
    const_cast<Eigen::MatrixBase<VectorType2>&>(res).coeffRef(2) 
        = - f_local.coeff(0) - mu * f_local.coeff(2) / std::sqrt(2);
    const_cast<Eigen::MatrixBase<VectorType2>&>(res).coeffRef(3) 
        = f_local.coeff(1) - mu * f_local.coeff(2) / std::sqrt(2);
    const_cast<Eigen::MatrixBase<VectorType2>&>(res).coeffRef(4) 
        = - f_local.coeff(1) - mu * f_local.coeff(2) / std::sqrt(2);
  }
 
  EIGEN_MAKE_ALIGNED_OPERATOR_NEW 
 
private:
  int dimv_, dimc_, max_num_contacts_;
  std::vector<int> contact_frame_;
  std::vector<ContactType> contact_types_;
 
  static Eigen::VectorXd& fW(ConstraintComponentData& data, 
                             const int contact_idx) {
    return data.r[contact_idx];
  }
 
  Eigen::VectorXd& r(ConstraintComponentData& data, 
                     const int contact_idx) const {
    return data.r[max_num_contacts_+contact_idx];
  }
 
  static Eigen::MatrixXd& dg_dq(ConstraintComponentData& data, 
                                const int contact_idx) {
    return data.J[contact_idx];
  }
 
  Eigen::MatrixXd& dg_df(ConstraintComponentData& data, 
                         const int contact_idx) const {
    return data.J[max_num_contacts_+contact_idx];
  }
 
  Eigen::MatrixXd& dfW_dq(ConstraintComponentData& data, 
                          const int contact_idx) const {
    return data.J[2*max_num_contacts_+contact_idx];
  }
 
  Eigen::MatrixXd& r_dg_df(ConstraintComponentData& data, 
                           const int contact_idx) const {
    return data.J[3*max_num_contacts_+contact_idx];
  }
 
  Eigen::MatrixXd& cone_local(ConstraintComponentData& data, 
                              const int contact_idx) const {
    return data.J[4*max_num_contacts_+contact_idx];
  }
 
  Eigen::MatrixXd& cone_world(ConstraintComponentData& data, 
                              const int contact_idx) const {
    return data.J[5*max_num_contacts_+contact_idx];
  }
 
};
 
} // namespace robotoc
 
#endif // ROBOTOC_FRICTION_CONE_HPP_