Program Listing for File SpringDamper.h#
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/**
* @file
* @brief Contains the declarations for the SpringDamper KModel.
*/
#pragma once
#include "Karana/Frame/ChainedFrameToFrame.h"
#include "Karana/SOADyn/KModel.h"
#include "Karana/SOADyn/Node.h"
namespace Karana::Models {
namespace km = Karana::Math;
namespace kd = Karana::Dynamics;
namespace kf = Karana::Frame;
/**
* @class SpringDamperParams
* @brief Parameters for the SpringDamper model.
*/
class SpringDamperParams : public KModelParams {
public:
/**
* @brief Constructor
* @param name - Name of the params.
*/
SpringDamperParams(std::string_view name);
/**
* @brief Used to ensure the params are ready.
*
* @return `true` if the params are ready, `false` otherwise.
*/
bool isReady() const final;
std::string
dumpString(std::string_view prefix,
const Karana::Core::Base::DumpOptions *options = nullptr) const override;
/// Unsprung length
double unsprung_length;
/// Spring constant
double k;
/// Damper constant
double d;
};
/**
* @class SpringDamperScratch
* @brief Scratch variables for the SpringDamper model.
*/
class SpringDamperScratch : public KModelScratch {
public:
/**
* @brief Constructor
* @param name - Name of the scratch.
*/
SpringDamperScratch(std::string_view name);
/// Translation from node1 to node2
km::Vec3 offset;
/// Signed length offset from the unsprung length
double position_error = km::notReadyNaN;
/// Relative linear velocity across the spring
km::Vec3 velocity_error;
/// Signed scalar force due to spring stiffness
double stiffness_force = km::notReadyNaN;
/// Linear force due to spring damping
km::Vec3 damping_force;
/// Total linear spring force
km::Vec3 total_force;
std::string
dumpString(std::string_view prefix,
const Karana::Core::Base::DumpOptions *options = nullptr) const override;
};
/**
* @class SpringDamper
* @brief Adds a spring-damper between two nodes.
*/
class SpringDamper : public KModel<SpringDamper, SpringDamperParams, SpringDamperScratch> {
public:
/**
* @brief SpringDamper constructor. The constructor is not meant to be called directly.
* Please use the create(...) method instead to create an instance.
* The SpringDamper model applies an equal and opposing force to two
* nodes based on their current distance apart.
*
* @param name The name of the model.
* @param mm The ModelManager to register this model with.
* @param nd1 The first node in the spring damper model.
* @param nd2 The second node in the spring damper model.
*/
SpringDamper(std::string_view name,
const kc::ks_ptr<kd::ModelManager> &mm,
const kc::ks_ptr<kd::Node> nd1,
const kc::ks_ptr<kd::Node> nd2);
/**
* @brief Destructor for SpringDamper.
*/
~SpringDamper();
/**
* @brief Constructor. The SpringDamper model applies an equal and opposing force to two
* nodes based on their current distance apart.
*
* @param name The name of the model.
* @param mm The ModelManager to register this model with.
* @param nd1 The first node in the spring damper model.
* @param nd2 The second node in the spring damper model.
* @return A ks_ptr to the newly created instance of the SpringDamper model.
*/
static kc::ks_ptr<SpringDamper> create(std::string_view name,
const kc::ks_ptr<kd::ModelManager> &mm,
const kc::ks_ptr<kd::Node> nd1,
const kc::ks_ptr<kd::Node> nd2);
/**
* @brief Calculate and apply the spring/damper force.
* @param t Current time. Not used.
* @param x Current state. Not used.
*/
void preDeriv(const km::Ktime &t, const km::Vec &x);
/**
* @brief Get the first node of the spring-damper
*
* @return The node
*/
const kc::ks_ptr<kd::Node> &sourceNode() const;
/**
* @brief Get the second node of the spring-damper
*
* @return The node
*/
const kc::ks_ptr<kd::Node> &targetNode() const;
private:
/// The first node of the spring-damper.
kc::ks_ptr<kd::Node> _nd1;
/// The second node of the spring-damper.
kc::ks_ptr<kd::Node> _nd2;
/// FrameToFrame between the newtonian frame and node1
kc::ks_ptr<kf::ChainedFrameToFrame> _f2f1;
/// FrameToFrame between the newtonian frame and node2
kc::ks_ptr<kf::ChainedFrameToFrame> _f2f2;
/// The newtonian frame of the multibody
kc::ks_ptr<kf::Frame> _newton;
};
} // namespace Karana::Models