force.hpp

//
// Copyright (c) 2020 INRIA
//

#ifndef __pinocchio_algorithm_utils_force_hpp__
#define __pinocchio_algorithm_utils_force_hpp__

#include "pinocchio/spatial/se3.hpp"
#include "pinocchio/spatial/force.hpp"
#include "pinocchio/multibody/fwd.hpp"

namespace pinocchio
{
 template<typename Scalar, int Options, typename ForceIn, typename ForceOut>
 void changeReferenceFrame(
 const SE3Tpl<Scalar, Options> & placement,
 const ForceDense<ForceIn> & f_in,
 const ReferenceFrame rf_in,
 const ReferenceFrame rf_out,
 ForceDense<ForceOut> & f_out)
 {
 if (rf_in == rf_out)
 {
 f_out = f_in;
 return;
 }

 // case: LOCAL/WORLD and WORLD/LOCAL
 if (rf_in == LOCAL && rf_out == WORLD)
 {
 f_out = placement.act(f_in);
 return;
 }
 if (rf_in == WORLD && rf_out == LOCAL)
 {
 f_out = placement.actInv(f_in);
 return;
 }

 // case: LOCAL/LOCAL_WORLD_ALIGNED and LOCAL_WORLD_ALIGNED/LOCAL
 if (rf_in == LOCAL && rf_out == LOCAL_WORLD_ALIGNED)
 {
 f_out.angular().noalias() = placement.rotation() * f_in.angular();
 f_out.linear().noalias() = placement.rotation() * f_in.linear();
 return;
 }
 if (rf_in == LOCAL_WORLD_ALIGNED && rf_out == LOCAL)
 {
 f_out.angular().noalias() = placement.rotation().transpose() * f_in.angular();
 f_out.linear().noalias() = placement.rotation().transpose() * f_in.linear();
 return;
 }

 // case: WORLD/LOCAL_WORLD_ALIGNED and LOCAL_WORLD_ALIGNED/WORLD
 if (rf_in == WORLD && rf_out == LOCAL_WORLD_ALIGNED)
 {
 f_out.linear() = f_in.linear();
 f_out.angular().noalias() = f_in.angular() + f_in.linear().cross(placement.translation());
 return;
 }
 if (rf_in == LOCAL_WORLD_ALIGNED && rf_out == WORLD)
 {
 f_out.linear() = f_in.linear();
 f_out.angular().noalias() = f_in.angular() - f_in.linear().cross(placement.translation());
 return;
 }

 assert(false && "This must never happened.");
 }

 template<typename Scalar, int Options, typename ForceIn>
 typename ForceIn::ForcePlain changeReferenceFrame(
 const SE3Tpl<Scalar, Options> & placement,
 const ForceDense<ForceIn> & f_in,
 const ReferenceFrame rf_in,
 const ReferenceFrame rf_out)
 {
 typedef typename ForceIn::ForcePlain ReturnType;
 ReturnType res;

 changeReferenceFrame(placement, f_in, rf_in, rf_out, res);

 return res;
 }

} // namespace pinocchio

#endif // #ifndef __pinocchio_algorithm_utils_force_hpp__