ExponentialSpringForce.h

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#ifndef SimTK_SIMBODY_EXPONENTIAL_SPRING_FORCE_H_
#define SimTK_SIMBODY_EXPONENTIAL_SPRING_FORCE_H_
 
/*-----------------------------------------------------------------------------
                               Simbody(tm)
-------------------------------------------------------------------------------
 Copyright (c) 2021-22 Authors.
 Authors: Frank C. Anderson
 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 "SimTKmath.h"
#include "simbody/internal/ExponentialSpringParameters.h"
#include "simbody/internal/Force.h"
 
namespace SimTK {
 
class MultibodySystem;
class MultibodySubsystem;
class MobilizedBody;
class ExponentialSpringForceImpl;
 
//=============================================================================
class SimTK_SIMBODY_EXPORT ExponentialSpringForce : public Force {
public:
    ExponentialSpringForce(GeneralForceSubsystem& forces,
        const Transform& X_GP,
        const MobilizedBody& body_B, const Vec3& station_B,
        ExponentialSpringParameters params = ExponentialSpringParameters());
 
    const Transform& getContactPlaneTransform() const;
 
    const MobilizedBody& getBody() const;
 
    const Vec3& getStation() const;
 
    void setParameters(const ExponentialSpringParameters& params);
 
    const ExponentialSpringParameters& getParameters() const;
 
    void setMuStatic(State& state, Real mus);
 
    Real getMuStatic(const State& state) const;
 
    void setMuKinetic(State& state, Real muk);
 
    Real getMuKinetic(const State& state) const;
 
    Real getSliding(const State& state) const;
 
    Vec3 getAnchorPointPosition(const State& state,
        bool inGround = true) const;
 
    void resetAnchorPoint(State& state) const;
 
    Vec3 getNormalForceElasticPart(const State& state,
        bool inGround = true) const;
 
    Vec3 getNormalForceDampingPart(const State& state,
        bool inGround = true) const;
 
    Vec3 getNormalForce(const State& state,
        bool inGround = true) const;
 
    Real getMu(const State& state) const;
 
    Real getFrictionForceLimit(const State& state) const;
 
    Vec3 getFrictionForceElasticPart(
        const State& state, bool inGround = true) const;
 
    Vec3 getFrictionForceDampingPart(
        const State& state, bool inGround = true) const;
 
    Vec3 getFrictionForce(const State& state, bool inGround = true) const;
 
    Vec3 getForce(const State& state, bool inGround = true) const;
 
    Vec3 getStationPosition(const State& state, bool inGround = true) const;
 
    Vec3 getStationVelocity(const State& state, bool inGround = true) const;
 
 
    // ADVANCED METHODS BELOW HERE
 
 
    DiscreteVariableIndex getMuStaticStateIndex() const;
 
    DiscreteVariableIndex getMuKineticStateIndex() const;
 
    DiscreteVariableIndex getSlidingStateIndex() const;
 
    DiscreteVariableIndex getAnchorPointStateIndex() const;
 
 
private:
    SimTK_INSERT_DERIVED_HANDLE_DECLARATIONS(
        ExponentialSpringForce, ExponentialSpringForceImpl, Force);
    Stage getStage(const State& state) const {
        return getForceSubsystem().getStage(state);
    }
};
 
 
} // namespace SimTK
#endif // SimTK_SIMBODY_EXPONENTIAL_SPRING_FORCE_H_