Module: polyhedralGravityModel

class PolyhedralGravityModel : public GravityModel

#include <polyhedralGravityModel.h>

The Polyhedral gravity model.

In this class, a polyhedron is defined by its triangular facets. Each facet is defined by three vertices (they are triangles), and each vertex is defined by its position relative to the center of mass of the body.

Public Functions

std::optional<std::string> initializeParameters() override

Initialize all parameters necessary for the computation of gravity.

The attribute muBody must be set separately.

Will return an error message (string) if xyzVertex or orderFacet were not set. Otherwise, returns an empty optional.

std::optional<std::string> initializeParameters(const GravBodyData&) override

Initialize all parameters necessary for the computation of gravity.

The attribute muBody is read from the given GravBodyData.

Will return an error message (string) if xyzVertex or orderFacet were not set. Otherwise, returns an empty optional.

Eigen::Vector3d computeField(const Eigen::Vector3d &position_planetFixed) const override

Returns the gravity acceleration at a position around this body.

The position is given in the body-fixed reference frame. Likewise, the resulting acceleration should be given in the body-fixed reference frame.

double computePotentialEnergy(const Eigen::Vector3d &positionWrtPlanet_N) const override

Returns the gravitational potential energy at a position around this body.

The current implementation returns the potential energy of a point-mass (the polyhedral shape of the body is ignored)

The position is given relative to the body and in the inertial reference frame.

Public Members

double muBody = 0

[m^3/s^2] Gravitation parameter for the planet

Eigen::MatrixX3d xyzVertex

This matrix contains the position of every vertex of this polyhedron, in meters. Each row corresponds to a different vertex, while each column corresponds to x, y, z respectively.

Eigen::MatrixX3i orderFacet

This matrix defines the facets of the matrix. Each row contains three numbers, each of them corresponding to the index of a vertex, as defined in xyzVertex. These three vertices define a single facet of the polyhedron.

Note that the order of the vertex index is important: the facets must all be outward pointing.

Private Members

double volPoly = 0

[m^3] Volume of the polyhedral

Eigen::MatrixX3d normalFacet

[-] Normal of a facet