EscapeController.cpp

Go to the documentation of this file.

/*
 * Copyright © 2012, United States Government, as represented by the
 * Administrator of the National Aeronautics and Space Administration.
 * All rights reserved.
 * 
 * The NASA Tensegrity Robotics Toolkit (NTRT) v1 platform is 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.
 */

// This module
#include "EscapeController.h"
// This application
#include "EscapeModel.h"
// This library
#include "core/tgBasicActuator.h"
// For AnnealEvolution
#include "learning/Configuration/configuration.h"
#include "learning/AnnealEvolution/AnnealEvolution.h"
#include "learning/Adapters/AnnealAdapter.h"
// File helpers to use resources folder
#include "helpers/FileHelpers.h"
// The C++ Standard Library
#include <cassert>
#include <cmath>
#include <stdexcept>
#include <vector>
#include <string>

# define M_PI 3.14159265358979323846 
                               
//Constructor using the model subject and a single pref length for all muscles.
//Currently calibrated to decimeters
EscapeController::EscapeController(const double initialLength,
                                    std::string args,
                                    std::string resourcePath,
                                    std::string config) :
    m_initialLengths(initialLength),
    m_totalTime(0.0),
    maxStringLengthFactor(0.50),
    nClusters(8),
    musclesPerCluster(3),
    suffix(args),
    configPath(resourcePath),
    configName(config)
{
    clusters.resize(nClusters);
    for (int i=0; i<nClusters; i++) {
        clusters[i].resize(musclesPerCluster);
    }
}

void EscapeController::onSetup(EscapeModel& subject)
{
    m_totalTime = 0;
    double dt = 0.0001;

    //Set the initial length of every muscle in the subject
    const std::vector<tgBasicActuator*> muscles = subject.getAllMuscles();
    for (size_t i = 0; i < muscles.size(); ++i) {
        tgBasicActuator * const pMuscle = muscles[i];
        assert(pMuscle != NULL);
        pMuscle->setControlInput(this->m_initialLengths, dt);
    }

    populateClusters(subject);
    initPosition = subject.getBallCOM();
    setupAdapter();
    initializeSineWaves(); // For muscle actuation

    std::vector<double> state; // For config file usage (including Monte Carlo simulations)

    //get the actions (between 0 and 1) from evolution (todo)
    actions = evolutionAdapter.step(dt,state);
 
    //transform them to the size of the structure
    actions = transformActions(actions);

    //apply these actions to the appropriate muscles according to the sensor values
    applyActions(subject,actions);
}

void EscapeController::onStep(EscapeModel& subject, double dt)
{
    if (dt <= 0.0) {
        throw std::invalid_argument("dt is not positive");
    }
    m_totalTime+=dt;

    setPreferredMuscleLengths(subject, dt);
    const std::vector<tgBasicActuator*> muscles = subject.getAllMuscles();
    
    //Move motors for all the muscles
    for (size_t i = 0; i < muscles.size(); ++i)
    {
        tgBasicActuator * const pMuscle = muscles[i];
        assert(pMuscle != NULL);
        pMuscle->moveMotors(dt);
    }
}

// So far, only score used for eventual fitness calculation of an Escape Model
// is the maximum distance from the origin reached during that subject's episode
void EscapeController::onTeardown(EscapeModel& subject) {
    std::vector<double> scores; //scores[0] == displacement, scores[1] == energySpent
    double distance = displacement(subject);
    double energySpent = totalEnergySpent(subject);

    //Invariant: For now, scores must be of size 2 (as required by endEpisode())
    scores.push_back(distance);
    scores.push_back(energySpent);

    std::cout << "Tearing down" << std::endl;
    evolutionAdapter.endEpisode(scores);

    // If any of subject's dynamic objects need to be freed, this is the place to do so
}

std::vector< std::vector <double> > EscapeController::transformActions(std::vector< std::vector <double> > actions)
{
    bool usingManualParams = false;
    std::vector <double> manualParams(4 * nClusters, 1); // '4' for the number of sine wave parameters
    if (usingManualParams) { 
        std::cout << "Using manually set parameters\n"; 
        std::string filename = "logs/paramSortedBestTrials.dat";
        int lineNumber = 1;
        manualParams = readManualParams(lineNumber, filename);
    } 

    double pretension = 0.90; // Tweak this value if need be
    // Minimum amplitude, angularFrequency, phaseChange, and dcOffset
    double mins[4]  = {m_initialLengths * (pretension - maxStringLengthFactor), 
                       0.3, //Hz
                       -1 * M_PI, 
                       m_initialLengths};// * (1 - maxStringLengthFactor)};

    // Maximum amplitude, angularFrequency, phaseChange, and dcOffset
    double maxes[4] = {m_initialLengths * (pretension + maxStringLengthFactor), 
                       20, //Hz (can cheat to 50Hz, if feeling immoral)
                       M_PI, 
                       m_initialLengths};// * (1 + maxStringLengthFactor)}; 
    double ranges[4] = {maxes[0]-mins[0], maxes[1]-mins[1], maxes[2]-mins[2], maxes[3]-mins[3]};

    for(int i=0;i<actions.size();i++) { //8x
        for (int j=0; j<actions[i].size(); j++) { //4x
            if (usingManualParams) {
                actions[i][j] = manualParams[i*actions[i].size() + j]*(ranges[j])+mins[j];
            } else {
                actions[i][j] = actions[i][j]*(ranges[j])+mins[j];
            }
        }
    }
    return actions;
}

void EscapeController::applyActions(EscapeModel& subject, std::vector< std::vector <double> > actions)
{
    assert(actions.size() == clusters.size());

    // Apply actions by cluster
    for (size_t cluster = 0; cluster < clusters.size(); cluster++) {
        amplitude[cluster] = actions[cluster][0];
        angularFrequency[cluster] = actions[cluster][1];
        phaseChange[cluster] = actions[cluster][2];
        dcOffset[cluster] = actions[cluster][3];
        dcOffset[cluster] = 1;
    }
    //printSineParams();
}

void EscapeController::setupAdapter() {
    //std::string suffix = "_Escape";
    
    std::string path;
    if (configPath != "")
    {
        path = FileHelpers::getResourcePath(configPath);
    }
    else
    {
        path = "";
    }
    
    std::string configAnnealEvolution = path + configName;
    AnnealEvolution* evo = new AnnealEvolution(suffix, configName, configPath);
    bool isLearning = true;
    configuration configEvolutionAdapter;
    configEvolutionAdapter.readFile(configAnnealEvolution);

    evolutionAdapter.initialize(evo, isLearning, configEvolutionAdapter);
}

double EscapeController::totalEnergySpent(EscapeModel& subject) {
    double totalEnergySpent=0;

    std::vector<tgBasicActuator* > tmpStrings = subject.getAllMuscles();
    for(int i=0; i<tmpStrings.size(); i++)
    {
        tgSpringCableActuator::SpringCableActuatorHistory stringHist = tmpStrings[i]->getHistory();

        for(int j=1; j<stringHist.tensionHistory.size(); j++)
        {
            const double previousTension = stringHist.tensionHistory[j-1];
            const double previousLength = stringHist.restLengths[j-1];
            const double currentLength = stringHist.restLengths[j];
            //TODO: examine this assumption - free spinning motor may require more power         
            double motorSpeed = (currentLength-previousLength);
            if(motorSpeed > 0) // Vestigial code
                motorSpeed = 0;
            const double workDone = previousTension * motorSpeed;
            totalEnergySpent += workDone;
        }
    }
    return totalEnergySpent;
}

// Pre-condition: every element in muscles must be defined
// Post-condition: every muscle will have a new target length
void EscapeController::setPreferredMuscleLengths(EscapeModel& subject, double dt) {
    double phase = 0; // Phase of cluster1
    
    int nMuscles = 24;
    int oldCluster = 0;
    int cluster = 0;

    for(int iMuscle=0; iMuscle < nMuscles; iMuscle++) {

        const std::vector<tgBasicActuator*> muscles = subject.getAllMuscles();
        tgBasicActuator *const pMuscle = muscles[iMuscle];

        assert(pMuscle != NULL);

        // Determine cluster
        oldCluster = cluster;
        if (iMuscle < 4) {
            cluster = 0;
        } else if (iMuscle < 8) {
            cluster = 1;
        } else if (iMuscle < 12) {
            cluster = 2;
        } else if (iMuscle < 16 ) {
            cluster = 3;
        } else if (iMuscle < 18) {
            cluster = 4;
        } else if (iMuscle < 20) {
            cluster = 5;
        } else if (iMuscle < 22) {
            cluster = 6;
        } else { // iMuscle < 24
            cluster = 7;
        }

        double newLength = amplitude[cluster] * sin(angularFrequency[cluster] * m_totalTime + phase) + dcOffset[cluster];
        double minLength = m_initialLengths * (1-maxStringLengthFactor);
        double maxLength = m_initialLengths * (1+maxStringLengthFactor);
        if (newLength <= minLength) {
            newLength = minLength;
        } else if (newLength >= maxLength) {
            newLength = maxLength;
        }
        pMuscle->setControlInput(newLength, dt);
        if (oldCluster != cluster) {
            phase += phaseChange[cluster];
        }
    }

    /*
    for(int cluster=0; cluster<nClusters; cluster++) {
        for(int node=0; node<musclesPerCluster; node++) {
            tgBasicActuator *const pMuscle = clusters[cluster][node];
            assert(pMuscle != NULL);
            double newLength = amplitude[cluster] * sin(angularFrequency[cluster] * m_totalTime + phase) + dcOffset[cluster];
            double minLength = m_initialLengths * (1-maxStringLengthFactor);
            double maxLength = m_initialLengths * (1+maxStringLengthFactor);
            if (newLength <= minLength) {
                newLength = minLength;
            } else if (newLength >= maxLength) {
                newLength = maxLength;
            }
            pMuscle->setControlInput(newLength, dt);
        }
        phase += phaseChange[cluster];
    }*/
}

void EscapeController::populateClusters(EscapeModel& subject) {
    for(int cluster=0; cluster < nClusters; cluster++) {
        std::ostringstream ss;
        ss << (cluster + 1);
        std::string suffix = ss.str();
        std::vector <tgBasicActuator*> musclesInThisCluster = subject.find<tgBasicActuator>("muscle cluster" + suffix);
        clusters[cluster] = std::vector<tgBasicActuator*>(musclesInThisCluster);
    }
}

void EscapeController::initializeSineWaves() {
    amplitude = new double[nClusters];
    angularFrequency = new double[nClusters];
    phaseChange = new double[nClusters]; // Does not use last value stored in array
    dcOffset = new double[nClusters];    
}

double EscapeController::displacement(EscapeModel& subject) {
    std::vector<double> finalPosition = subject.getBallCOM();

    // 'X' and 'Z' are irrelevant. Both variables measure lateral direction
    //assert(finalPosition[0] > 0); //Negative y-value indicates a flaw in the simulator that run (tensegrity went 'underground')

    const double newX = finalPosition[0];
    const double newZ = finalPosition[2];
    const double oldX = initPosition[0];
    const double oldZ = initPosition[2];

    const double distanceMoved = sqrt((newX-oldX) * (newX-oldX) + 
                                      (newZ-oldZ) * (newZ-oldZ));
    return distanceMoved;
}
                                         
std::vector<double> EscapeController::readManualParams(int lineNumber, std::string filename) {
    assert(lineNumber > 0);
    std::vector<double> result(32, 1.0);
    std::string line;
    std::ifstream infile(filename.c_str(), std::ifstream::in);

    // Grab line from input file
    if (infile.is_open()) {
        std::cout << "OPENED FILE\n";
        for (int i=0; i<lineNumber; i++) {
            getline(infile, line);
        }
        infile.close();
    } else {
        std::cerr << "Error: Manual Parameters file not found\n";
        exit(1);
    }

    //cout << "Using: " << line << " as input for starting parameter values\n";

    // Split line into parameters
    std::stringstream lineStream(line);
    std::string cell;
    int iCell = 0;
    while(getline(lineStream,cell,',')) {
        result[iCell] = atof(cell.c_str());
        iCell++;
    }

    bool tweaking = false;
    if (tweaking) {
        // Tweak each read-in parameter by as much as 0.5% (params range: [0,1])
        for (int i=0; i < result.size(); i++) {
            std::cout<<"Entered Cell " << i << ": " << result[i] << "\n";
            double seed = ((double) (rand() % 100)) / 100;
            result[i] += (0.01 * seed) - 0.005; // Value +/- 0.005 of original
        }
    } else {
        std::cerr << "WARNING: Not changing manual input parameters\n";
    }

    return result;
}

void EscapeController::printSineParams() {
    for (size_t cluster = 0; cluster < clusters.size(); cluster++) {
        std::cout << "amplitude[" << cluster << "]: " << amplitude[cluster] << std::endl;
        std::cout << "angularFrequency[" << cluster << "]: " << angularFrequency[cluster] << std::endl;
        std::cout << "phaseChange[" << cluster << "]: " << phaseChange[cluster] << std::endl;
        std::cout << "dcOffset[" << cluster << "]: " << dcOffset[cluster] << std::endl;
    }    
}