CableSpring.h

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#ifndef SimTK_SIMBODY_CABLE_SPRING_H_
#define SimTK_SIMBODY_CABLE_SPRING_H_

/* -------------------------------------------------------------------------- *
 *                               Simbody(tm)                                  *
 * -------------------------------------------------------------------------- *
 * This is part of the SimTK biosimulation toolkit originating from           *
 * Simbios, the NIH National Center for Physics-Based Simulation of           *
 * Biological Structures at Stanford, funded under the NIH Roadmap for        *
 * Medical Research, grant U54 GM072970. See https://simtk.org/home/simbody.  *
 *                                                                            *
 * Portions copyright (c) 2012-13 Stanford University and the Authors.        *
 * Authors: Michael Sherman                                                   *
 * Contributors:                                                              *
 *                                                                            *
 * Licensed under the Apache License, Version 2.0 (the "License"); you may    *
 * not use this file except in compliance with the License. You may obtain a  *
 * copy of the License at http://www.apache.org/licenses/LICENSE-2.0.         *
 *                                                                            *
 * Unless required by applicable law or agreed to in writing, software        *
 * distributed under the License is distributed on an "AS IS" BASIS,          *
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.   *
 * See the License for the specific language governing permissions and        *
 * limitations under the License.                                             *
 * -------------------------------------------------------------------------- */

#include "SimTKcommon.h"
#include "simbody/internal/common.h"
#include "simbody/internal/Force.h"
#include "simbody/internal/CablePath.h"

namespace SimTK {

class SimTK_SIMBODY_EXPORT CableSpring : public Force {
public:

CableSpring(GeneralForceSubsystem&  forces, 
            const CablePath&        path, 
            Real                    defaultStiffness, 
            Real                    defaultSlackLength, 
            Real                    defaultDissipationCoef);

CableSpring() {}


//------------------------------------------------------------------------------
CableSpring& setDefaultStiffness(Real stiffness);
CableSpring& setDefaultSlackLength(Real slackLength);
CableSpring& setDefaultDissipationCoef(Real dissipation);

Real getDefaultStiffness() const;
Real getDefaultSlackLength() const;
Real getDefaultDissipationCoef() const;
//------------------------------------------------------------------------------
const CableSpring& setStiffness(State&      state, 
                                Real        stiffness) const;
const CableSpring& setSlackLength(State&    state, 
                                  Real      slackLength) const;
const CableSpring& setDissipationCoef(State&    state, 
                                      Real      dissipationCoef) const;

Real getStiffness(const State& state) const;
Real getSlackLength(const State& state) const;
Real getDissipationCoef(const State& state)   const;
//------------------------------------------------------------------------------
Real getLength(const State& state) const;
//------------------------------------------------------------------------------
Real getLengthDot(const State& state) const;

//------------------------------------------------------------------------------
Real getTension(const State& state) const;
//------------------------------------------------------------------------------
Real getPotentialEnergy(const State& state) const;

Real getPowerDissipation(const State& state) const;

Real getDissipatedEnergy(const State& state) const;

void setDissipatedEnergy(State& state, Real energy) const;
const CablePath& getCablePath() const; // Don't show this in Doxygen.
class Impl;
SimTK_INSERT_DERIVED_HANDLE_DECLARATIONS
    (CableSpring, CableSpring::Impl, Force);
};

} // namespace SimTK

#endif // SimTK_SIMBODY_CABLE_SPRING_H_