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#ifndef SimTK_SIMBODY_SMOOTH_SPHERE_HALFSPACE_FORCE_IMPL_H_
#define SimTK_SIMBODY_SMOOTH_SPHERE_HALFSPACE_FORCE_IMPL_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) 2008-19 Stanford University and the Authors. *
* Authors: Antoine Falisse, Gil Serrancoli *
* Contributors: Peter Eastman *
* *
* 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/SmoothSphereHalfSpaceForce.h"
#include "ForceImpl.h"
namespace SimTK {
class SmoothSphereHalfSpaceForceImpl : public ForceImpl {
public:
class Parameters {
public:
Parameters() : stiffness(1), dissipation(0), staticFriction(0),
dynamicFriction(0), viscousFriction(0), transitionVelocity(0.01),
cf(1e-5), bd(300), bv(50) {
}
Parameters(Real stiffness, Real dissipation, Real staticFriction,
Real dynamicFriction, Real viscousFriction,
Real transitionVelocity, Real cf, Real bd, Real bv) :
stiffness(stiffness), dissipation(dissipation),
staticFriction(staticFriction), dynamicFriction(dynamicFriction),
viscousFriction(viscousFriction),
transitionVelocity(transitionVelocity), cf(cf), bd(bd), bv(bv) {
}
Real stiffness, dissipation, staticFriction, dynamicFriction,
viscousFriction, transitionVelocity, cf, bd, bv;
};
Real contactSphereRadius;
Vec3 contactSphereLocation;
Transform contactHalfSpaceFrame;
MobilizedBody bodySphere;
MobilizedBody bodyHalfSpace;
Parameters parameters;
SmoothSphereHalfSpaceForceImpl(GeneralForceSubsystem& subsystem);
SmoothSphereHalfSpaceForceImpl* clone() const override {
return new SmoothSphereHalfSpaceForceImpl(*this);
}
// Set the contact material parameters.
void setParameters(Real stiffness, Real dissipation, Real staticFriction,
Real dynamicFriction, Real viscousFriction, Real transitionVelocity,
Real cf, Real bd, Real bv);
// Get parameters.
const Parameters& getParameters() const;
// Update parameters.
Parameters& updParameters();
// Set the stiffness constant (i.e., plain strain modulus), default is 1
// N/m^2.
void setStiffness(Real stiffness);
// Set the dissipation coefficient, default is 0 s/m.
void setDissipation(Real dissipation);
// Set the coefficient of static friction, default is 0.
void setStaticFriction(Real staticFriction);
// Set the coefficient of dynamic friction, default is 0.
void setDynamicFriction(Real dynamicFriction);
// Set the coefficient of viscous friction, default is 0.
void setViscousFriction(Real viscousFriction);
// Set the transition velocity, default is 0.01 m/s.
void setTransitionVelocity(Real transitionVelocity);
// Set the constant that enforces non-null derivatives, default is 1e-5.
void setConstantContactForce(Real cf);
// Set the parameter that determines the smoothness of the transition
// of the tanh used to smooth the Hertz force. The larger the steeper the
// transition but also the more discontinuous, default is 300.
void setHertzSmoothing(Real bd);
// Set the parameter that determines the smoothness of the transition of
// the tanh used to smooth the Hunt-Crossley force. The larger the steeper
// the transition but also the more discontinuous, default is 50.
void setHuntCrossleySmoothing(Real bv);
// Set the MobilizedBody to which the contact sphere is attached.
void setContactSphereBody(MobilizedBody bodyInput1);
// Set the location of the contact sphere in the body frame.
void setContactSphereLocationInBody(Vec3 locationContactSphere);
// Set the radius of the contact sphere.
void setContactSphereRadius(Real radius);
// Set the MobilizedBody to which the contact half space is attached.
void setContactHalfSpaceBody(MobilizedBody bodyInput2);
// Set the transform of the contact half space in the body frame.
void setContactHalfSpaceFrame(Transform halfSpaceFrame);
// Get the MobilizedBody to which the contact sphere is attached.
MobilizedBody getBodySphere();
// Get the MobilizedBody to which the contact half space is attached.
MobilizedBody getBodyHalfSpace();
// Get the location of the contact sphere in the body frame.
Vec3 getContactSphereLocationInBody();
// Get the radius of the contact sphere.
Real getContactSphereRadius();
// Get the transform of the contact half space.
Transform getContactHalfSpaceTransform();
// Get the normal to the contact half space.
void getNormalContactHalfSpace(const State& state,
UnitVec3& normalContactHalfSpace) const;
// Get the location of the contact sphere origin in the ground frame.
void getContactSphereOrigin(const State& state,Vec3& contactPointPos)const;
// Calculate contact force.
void calcForce(const State& state, Vector_<SpatialVec>& bodyForces,
Vector_<Vec3>& particleForces, Vector& mobilityForces) const override;
// Calculate potential energy.
Real calcPotentialEnergy(const State& state) const override;
void realizeTopology(State& state) const override;
private:
const GeneralForceSubsystem& subsystem;
mutable CacheEntryIndex energyCacheIndex;
};
} // namespace SimTK
#endif // SimTK_SIMBODY_SMOOTH_SPHERE_HALFSPACE_FORCE_IMPL_H_
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