ActionModel.h

Go to the documentation of this file.

/*******************************************************************************
 Copyright (c) 2020, Fabio Muratore, Honda Research Institute Europe GmbH, and
 Technical University of Darmstadt.
 All rights reserved.

 Redistribution and use in source and binary forms, with or without
 modification, are permitted provided that the following conditions are met:
 1. Redistributions of source code must retain the above copyright
    notice, this list of conditions and the following disclaimer.
 2. Redistributions in binary form must reproduce the above copyright
    notice, this list of conditions and the following disclaimer in the
    documentation and/or other materials provided with the distribution.
 3. Neither the name of Fabio Muratore, Honda Research Institute Europe GmbH,
    or Technical University of Darmstadt, nor the names of its contributors may
    be used to endorse or promote products derived from this software without
    specific prior written permission.

 THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 DISCLAIMED. IN NO EVENT SHALL FABIO MURATORE, HONDA RESEARCH INSTITUTE EUROPE GMBH,
 OR TECHNICAL UNIVERSITY OF DARMSTADT BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
 PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
 OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER
 IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 POSSIBILITY OF SUCH DAMAGE.
*******************************************************************************/

#ifndef _ACTIONMODEL_H_
#define _ACTIONMODEL_H_

#include "../util/BoxSpaceProvider.h"

#include <Rcs_MatNd.h>
#include <Rcs_graph.h>
#include <Rcs_typedef.h>

namespace Rcs
{

/*! Combination method for tasks a.k.a. movement primitives
 * Determines how the contribution of each task is scaled with its activation.
 */
enum class TaskCombinationMethod
{
    Sum, Mean, SoftMax, Product
};


/**
 * The ActionModel component encapsulates the translation from the generic action passed from Python to actual joint
 * space commands required by the physics simulation or the robot.
 * Inherits from BoxSpaceProvider to provide a space for valid action values.
 */
class ActionModel : public BoxSpaceProvider
{
public:
    /**
     * Constructor
     * @param graph graph being commanded
     */
    explicit ActionModel(RcsGraph* graph);
    
    virtual ~ActionModel();
    
    /**
     * Create a deep copy of this action model.
     * @return deep copy.
     */
    inline ActionModel* clone() const { return clone(graph); }
    
    /**
     * Create a deep copy of this action model. The graph the action model operates on is replaced with newGraph.
     * @param newGraph optionally, replace the graph used with newGraph.
     * @return deep copy with new graph.
     */
    virtual ActionModel* clone(RcsGraph* newGraph) const = 0;
    
    /**
     * Compute the joint commands from a specified action and the current state.
     * @param[out] q_des desired joint positions
     * @param[out] q_dot_des desired joint velocities
     * @param[out] T_des desired joint torques
     * @param[in]  action input action values
     * @param      dt difference in time since the last call.
     */
    virtual void computeCommand(MatNd* q_des, MatNd* q_dot_des, MatNd* T_des, const MatNd* action, double dt) = 0;
    
    /**
     * Called at the start of a rollout to reset any state modified by computeCommand().
     * This allows to reuse the ActionModel for a new simulation rollout. The graph state will already be reset,
     * so it can be used safely.
     * It will be called before the first rollout too, so it can also be used to setup internals that depend on
     * operations in subclass constructors.
     */
    virtual void reset();
    
    /**
     * Obtain action values which would keep the system in the current state.
     * For action variables which are velocities or accelerations, this should be 0.
     * For action variables which are positions, this should be the current position.
     * @param[out] action matrix to write the values into
     */
    virtual void getStableAction(MatNd* action) const = 0;
    
    /**
     * Get the graph this action model operates on.
     */
    RcsGraph* getGraph() { return graph; }
    
    void setGraph(RcsGraph* newGraph) { graph = newGraph; }
    
    /*!
     * If this ActionModel is a wrapper for another action model, return the wrapped action model.
     * Otherwise, return NULL.
     * @return wrapped action model or NULL if none.
     */
    virtual ActionModel* getWrappedActionModel() const;
    
    /*!
     * Descend the wrapper chain to it's end.
     * Returns this action model if unwrap() returns NULL.
     * @return innermost action model
     */
    const ActionModel* unwrapAll() const;
    
    /*!
     * Descend the wrapper chain to it's end.
     * Returns this action model if unwrap() returns NULL.
     * @return innermost action model
     */
    ActionModel* unwrapAll();
    
    /*!
     * Find action model of a specific type in the wrapper chain.
     * @tparam AM type of action model to locate
     * @return typed action model or if not found.
     */
    template<typename AM>
    const AM* unwrap() const
    {
        const ActionModel* curr = this;
        // Loop through the chain
        while (true) {
            // Try to cast current action model
            auto cast = dynamic_cast<AM*>(curr);
            if (cast) {
                return cast;
            }
            
            // Obtain next wrapped action model
            const ActionModel* wrapped = curr->getWrappedActionModel();
            if (wrapped == NULL) {
                // end of chain
                return NULL;
            }
            // Descend
            curr = wrapped;
        }
    }
    
    /*!
     * Find action model of a specific type in the wrapper chain.
     * @tparam AM type of action model to locate
     * @return typed action model or if not found.
     */
    template<typename AM>
    AM* unwrap()
    {
        ActionModel* curr = this;
        // Loop through the chain
        while (true) {
            // Try to cast current action model
            auto cast = dynamic_cast<AM*>(curr);
            if (cast) {
                return cast;
            }
            
            // Obtain next wrapped action model
            ActionModel* wrapped = curr->getWrappedActionModel();
            if (wrapped == NULL) {
                // End of chain
                return NULL;
            }
            // Descend
            curr = wrapped;
        }
    }

protected:
    // Graph this action model operates on
    RcsGraph* graph;
};

} /* namespace Rcs */

#endif /* _ACTIONMODEL_H_ */