limiter.cpp

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/*
 * Copyright 2017 Fraunhofer Institute for Manufacturing Engineering and Automation (IPA)
 *
 * 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 <vector>
#include <ros/ros.h>
 
#include "cob_twist_controller/limiters/limiter.h"
 
/* BEGIN LimiterContainer ***************************************************************************************/
KDL::Twist LimiterContainer::enforceLimits(const KDL::Twist& v_in) const
{
    // If nothing to do just return v_in.
    KDL::Twist v_out(v_in);
    for (input_LimIter_t it = this->input_limiters_.begin(); it != this->input_limiters_.end(); it++)
    {
        v_out = (*it)->enforceLimits(v_out);
    }
 
    return v_out;
}
KDL::JntArray LimiterContainer::enforceLimits(const KDL::JntArray& q_dot_ik, const KDL::JntArray& q) const
{
    // If nothing to do just return q_dot.
    KDL::JntArray q_dot_norm(q_dot_ik);
    for (output_LimIter_t it = this->output_limiters_.begin(); it != this->output_limiters_.end(); it++)
    {
        q_dot_norm = (*it)->enforceLimits(q_dot_norm, q);
    }
 
    return q_dot_norm;
}
 
void LimiterContainer::init()
{
    this->eraseAll();
 
    if (limiter_params_.keep_direction)
    {
        if (limiter_params_.enforce_input_limits)
        {
            this->add(new LimiterAllCartesianVelocities(limiter_params_));
        }
 
        if (limiter_params_.enforce_pos_limits)
        {
            this->add(new LimiterAllJointPositions(limiter_params_));
        }
 
        if (limiter_params_.enforce_vel_limits)
        {
            this->add(new LimiterAllJointVelocities(limiter_params_));
        }
 
        if (limiter_params_.enforce_acc_limits)
        {
            this->add(new LimiterAllJointAccelerations(limiter_params_));
        }
    }
    else
    {
        if (limiter_params_.enforce_input_limits)
        {
            this->add(new LimiterIndividualCartesianVelocities(limiter_params_));
        }
 
        if (limiter_params_.enforce_pos_limits)
        {
            this->add(new LimiterIndividualJointPositions(limiter_params_));
        }
 
        if (limiter_params_.enforce_vel_limits)
        {
            this->add(new LimiterIndividualJointVelocities(limiter_params_));
        }
 
        if (limiter_params_.enforce_acc_limits)
        {
            this->add(new LimiterIndividualJointAccelerations(limiter_params_));
        }
    }
}
 
void LimiterContainer::eraseAll()
{
    for (uint32_t cnt = 0; cnt < this->input_limiters_.size(); ++cnt)
    {
        delete(this->input_limiters_[cnt]);
    }
    for (uint32_t cnt = 0; cnt < this->output_limiters_.size(); ++cnt)
    {
        delete(this->output_limiters_[cnt]);
    }
 
    this->input_limiters_.clear();
    this->output_limiters_.clear();
}
 
void LimiterContainer::add(const LimiterCartesianBase* lb)
{
    this->input_limiters_.push_back(lb);
}
void LimiterContainer::add(const LimiterJointBase* lb)
{
    this->output_limiters_.push_back(lb);
}
 
LimiterContainer::~LimiterContainer()
{
    this->eraseAll();
}
/* END LimiterContainer *****************************************************************************************/
 
/* BEGIN LimiterAllJointPositions *******************************************************************************/
KDL::JntArray LimiterAllJointPositions::enforceLimits(const KDL::JntArray& q_dot_ik, const KDL::JntArray& q) const
{
    KDL::JntArray q_dot_norm(q_dot_ik);
    double tolerance = limiter_params_.limits_tolerance / 180.0 * M_PI;
    double max_factor = 1.0;
    int joint_index = -1;
 
    for (unsigned int i = 0; i < q_dot_ik.rows(); i++)
    {
        if ((limiter_params_.limits_max[i] - LIMIT_SAFETY_THRESHOLD <= q(i) && q_dot_ik(i) > 0) ||
           (limiter_params_.limits_min[i] + LIMIT_SAFETY_THRESHOLD >= q(i) && q_dot_ik(i) < 0))
        {
            ROS_ERROR_STREAM("Joint " << i << " violates its limits. Setting to Zero!");
            KDL::SetToZero(q_dot_norm);
            return q_dot_norm;
        }
 
        if (fabs(limiter_params_.limits_max[i] - q(i)) <= tolerance)  // Joint is close to the MAXIMUM limit
        {
            if (q_dot_ik(i) > 0)  // Joint moves towards the MAX limit
            {
                double temp = 1.0 / pow((0.5 + 0.5 * cos(M_PI * (q(i) + tolerance - limiter_params_.limits_max[i]) / tolerance)), 5.0);
                // double temp = tolerance / fabs(limiter_params_.limits_max[i] - q(i));
                if (temp > max_factor)
                {
                    max_factor = temp;
                    joint_index = i;
                }
            }
        }
 
        if (fabs(q(i) - limiter_params_.limits_min[i]) <= tolerance)  // Joint is close to the MINIMUM limit
        {
            if (q_dot_ik(i) < 0)  // Joint moves towards the MIN limit
            {
                double temp = 1.0 / pow(0.5 + 0.5 * cos(M_PI * (q(i) - tolerance - limiter_params_.limits_min[i]) / tolerance), 5.0);
                // double temp = tolerance / fabs(q(i) - limiter_params_.limits_min[i]);
                if (temp > max_factor)
                {
                    max_factor = temp;
                    joint_index = i;
                }
            }
        }
    }
 
    if (max_factor > 1.0)
    {
        ROS_ERROR_STREAM_THROTTLE(1, "Position tolerance surpassed (by Joint " << joint_index << "): Scaling ALL VELOCITIES with factor = " << max_factor);
        for (unsigned int i = 0; i < q_dot_ik.rows(); i++)
        {
            q_dot_norm(i) = q_dot_ik(i) / max_factor;
        }
    }
 
    return q_dot_norm;
}
/* END LimiterAllJointPositions *********************************************************************************/
 
/* BEGIN LimiterAllJointVelocities ******************************************************************************/
KDL::JntArray LimiterAllJointVelocities::enforceLimits(const KDL::JntArray& q_dot_ik, const KDL::JntArray& q) const
{
    KDL::JntArray q_dot_norm(q_dot_ik);
    double max_factor = 1.0;
    int joint_index = -1;
 
    for (unsigned int i = 0; i < q_dot_ik.rows(); i++)
    {
        if (max_factor < std::fabs(q_dot_ik(i) / limiter_params_.limits_vel[i]))
        {
            max_factor = std::fabs(q_dot_ik(i) / limiter_params_.limits_vel[i]);
            joint_index = i;
        }
    }
 
    if (max_factor > 1.0)
    {
        ROS_WARN_STREAM_THROTTLE(1, "Velocity limit surpassed (by Joint " << joint_index << "): Scaling ALL VELOCITIES with factor = " << max_factor);
        for (unsigned int i = 0; i < q_dot_ik.rows(); i++)
        {
            q_dot_norm(i) = q_dot_ik(i) / max_factor;
        }
    }
 
    return q_dot_norm;
}
/* END LimiterAllJointVelocities ********************************************************************************/
 
/* BEGIN LimiterAllJointAccelerations ******************************************************************************/
KDL::JntArray LimiterAllJointAccelerations::enforceLimits(const KDL::JntArray& q_dot_ik, const KDL::JntArray& q) const
{
    KDL::JntArray q_dot_norm(q_dot_ik);
 
    ROS_WARN("LimiterAllJointAccelerations not yet implemented");
 
    return q_dot_norm;
}
/* END LimiterAllJointAccelerations *****************************************************************************/
 
/* BEGIN LimiterAllCartesianVelocities ********************************************************************/
KDL::Twist LimiterAllCartesianVelocities::enforceLimits(const KDL::Twist& v_in) const
{
    KDL::Twist v_out(v_in);
 
    double max_factor = 1.0;
    max_factor = std::max( max_factor, std::fabs(v_in.rot.x()/limiter_params_.max_rot_twist) );
    max_factor = std::max( max_factor, std::fabs(v_in.rot.y()/limiter_params_.max_rot_twist) );
    max_factor = std::max( max_factor, std::fabs(v_in.rot.z()/limiter_params_.max_rot_twist) );
    max_factor = std::max( max_factor, std::fabs(v_in.vel.x()/limiter_params_.max_lin_twist) );
    max_factor = std::max( max_factor, std::fabs(v_in.vel.y()/limiter_params_.max_lin_twist) );
    max_factor = std::max( max_factor, std::fabs(v_in.vel.z()/limiter_params_.max_lin_twist) );
 
    if (max_factor > 1.0)
    {
        ROS_WARN_STREAM_THROTTLE(1, "Cartesian velocity limit surpassed: Scaling ALL VELOCITIES with factor = " << max_factor);
        v_out.rot.x(v_in.rot.x()/max_factor);
        v_out.rot.y(v_in.rot.y()/max_factor);
        v_out.rot.z(v_in.rot.z()/max_factor);
        v_out.vel.x(v_in.vel.x()/max_factor);
        v_out.vel.y(v_in.vel.y()/max_factor);
        v_out.vel.z(v_in.vel.z()/max_factor);
        
    }
 
    return v_out;
}
/* END LimiterAllCartesianVelocities **********************************************************************/
 
/* BEGIN LimiterIndividualJointPositions ************************************************************************/
KDL::JntArray LimiterIndividualJointPositions::enforceLimits(const KDL::JntArray& q_dot_ik, const KDL::JntArray& q) const
{
    KDL::JntArray q_dot_norm(q_dot_ik);
    double tolerance = limiter_params_.limits_tolerance / 180.0 * M_PI;
 
    for (unsigned int i = 0; i < q_dot_ik.rows(); i++)
    {
        if ((limiter_params_.limits_max[i] - LIMIT_SAFETY_THRESHOLD <= q(i) && q_dot_ik(i) > 0) ||
           (limiter_params_.limits_min[i] + LIMIT_SAFETY_THRESHOLD >= q(i) && q_dot_ik(i) < 0))
        {
            ROS_ERROR_STREAM("Joint " << i << " violates its limits. Setting to Zero!");
            q_dot_norm(i) = 0.0;
        }
 
        double factor = 1.0;
        if (fabs(limiter_params_.limits_max[i] - q(i)) <= tolerance)  // Joint is close to the MAXIMUM limit
        {
            if (q_dot_ik(i) > 0.0)  // Joint moves towards the MAX limit
            {
                double temp = 1.0 / pow((0.5 + 0.5 * cos(M_PI * (q(i) + tolerance - limiter_params_.limits_max[i]) / tolerance)), 5.0);
                // double temp = tolerance / fabs(limiter_params_.limits_max[i] - q(i));
                factor = (temp > factor) ? temp : factor;
            }
        }
 
        if (fabs(q(i) - limiter_params_.limits_min[i]) <= tolerance)  // Joint is close to the MINIMUM limit
        {
            if (q_dot_ik(i) < 0.0)  // Joint moves towards the MIN limit
            {
                double temp = 1.0 / pow(0.5 + 0.5 * cos(M_PI * (q(i) - tolerance - limiter_params_.limits_min[i]) / tolerance), 5.0);
                // double temp = tolerance / fabs(q(i) - limiter_params_.limits_min[i]);
                factor = (temp > factor) ? temp : factor;
            }
        }
        q_dot_norm(i) = q_dot_norm(i) / factor;
    }
 
    return q_dot_norm;
}
/* END LimiterIndividualJointPositions **************************************************************************/
 
/* BEGIN LimiterIndividualJointVelocities ***********************************************************************/
KDL::JntArray LimiterIndividualJointVelocities::enforceLimits(const KDL::JntArray& q_dot_ik, const KDL::JntArray& q) const
{
    KDL::JntArray q_dot_norm(q_dot_ik);
 
    for (unsigned int i = 0; i < q_dot_ik.rows(); i++)
    {
        double factor = 1.0;
        if (factor < std::fabs(q_dot_ik(i) / limiter_params_.limits_vel[i]))
        {
            factor = std::fabs(q_dot_ik(i) / limiter_params_.limits_vel[i]);
            q_dot_norm(i) = q_dot_ik(i) / factor;
        }
    }
 
    return q_dot_norm;
}
/* END LimiterIndividualJointVelocities *************************************************************************/
 
/* BEGIN LimiterIndividualJointAccelerations ********************************************************************/
KDL::JntArray LimiterIndividualJointAccelerations::enforceLimits(const KDL::JntArray& q_dot_ik, const KDL::JntArray& q) const
{
    KDL::JntArray q_dot_norm(q_dot_ik);
 
    ROS_WARN("LimiterIndividualJointAccelerations not yet implemented");
 
    return q_dot_norm;
}
/* END LimiterIndividualJointAccelerations **********************************************************************/
 
/* BEGIN LimiterIndividualCartesianVelocities ********************************************************************/
KDL::Twist LimiterIndividualCartesianVelocities::enforceLimits(const KDL::Twist& v_in) const
{
    KDL::Twist v_out(v_in);
 
    // limiting rotational velocities
    if (v_in.rot.x() >limiter_params_.max_rot_twist)
        v_out.rot.x(limiter_params_.max_rot_twist);
    if (v_in.rot.x() <-limiter_params_.max_rot_twist)
        v_out.rot.x(-limiter_params_.max_rot_twist);
 
    if (v_in.rot.y() >limiter_params_.max_rot_twist)
        v_out.rot.y(limiter_params_.max_rot_twist);
    if (v_in.rot.y() <-limiter_params_.max_rot_twist)
        v_out.rot.y(-limiter_params_.max_rot_twist);
 
    if (v_in.rot.z() >limiter_params_.max_rot_twist)
        v_out.rot.z(limiter_params_.max_rot_twist);
    if (v_in.rot.z() <-limiter_params_.max_rot_twist)
        v_out.rot.z(-limiter_params_.max_rot_twist);
 
    // limiting linear velocities
    if (v_in.vel.x() >limiter_params_.max_lin_twist)
        v_out.vel.x(limiter_params_.max_lin_twist);
    if (v_in.vel.x() <-limiter_params_.max_lin_twist)
        v_out.vel.x(-limiter_params_.max_lin_twist);
 
    if (v_in.vel.y() >limiter_params_.max_lin_twist)
        v_out.vel.y(limiter_params_.max_lin_twist);
    if (v_in.vel.y() <-limiter_params_.max_lin_twist)
        v_out.vel.y(-limiter_params_.max_lin_twist);
 
    if (v_in.vel.z() >limiter_params_.max_lin_twist)
        v_out.vel.z(limiter_params_.max_lin_twist);
    if (v_in.vel.z() <-limiter_params_.max_lin_twist)
        v_out.vel.z(-limiter_params_.max_lin_twist);
 
    return v_out;
}
/* END LimiterIndividualCartesianVelocities **********************************************************************/