VelocitySmoothing.hpp

/****************************************************************************
 *
 *   Copyright (c) 2018 PX4 Development Team. 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 PX4 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 THE
 * COPYRIGHT OWNER OR CONTRIBUTORS 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.
 *
 ****************************************************************************/

#pragma once

class VelocitySmoothing
{
public:
    VelocitySmoothing(float initial_accel = 0.f, float initial_vel = 0.f, float initial_pos = 0.f);
    ~VelocitySmoothing() = default;

    void reset(float accel, float vel, float pos);

    void updateDurations(float dt, float vel_setpoint);

    void integrate(float &accel_setpoint_smooth, float &vel_setpoint_smooth, float &pos_setpoint_smooth);
    void integrate(float dt, float integration_scale_factor, float &accel_setpoint_smooth, float &vel_setpoint_smooth,
               float &pos_setpoint_smooth);

    /* Get / Set constraints (constraints can be updated at any time) */
    float getMaxJerk() const { return _max_jerk; }
    void setMaxJerk(float max_jerk) { _max_jerk = max_jerk; }

    float getMaxAccel() const { return _max_accel; }
    void setMaxAccel(float max_accel) { _max_accel = max_accel; }

    float getMaxVel() const { return _max_vel; }
    void setMaxVel(float max_vel) { _max_vel = max_vel; }

    float getCurrentJerk() const { return _jerk; }
    void setCurrentAcceleration(const float accel) { _accel = accel; }
    float getCurrentAcceleration() const { return _accel; }
    void setCurrentVelocity(const float vel) { _vel = vel; }
    float getCurrentVelocity() const { return _vel; }
    void setCurrentPosition(const float pos) { _pos = pos; }
    float getCurrentPosition() const { return _pos; }

    static void timeSynchronization(VelocitySmoothing *traj, int n_traj);

    float getTotalTime() const { return _T1 + _T2 + _T3; }
    float getT1() const { return _T1; }
    float getT2() const { return _T2; }
    float getT3() const { return _T3; }
    float getVelSp() const { return _vel_sp; }

private:

    void updateDurations(float T123 = -1.f);
    inline float computeT1(float accel_prev, float vel_prev, float vel_setpoint, float max_jerk);
    inline float computeT1(float T123, float accel_prev, float vel_prev, float vel_setpoint, float max_jerk);
    inline float saturateT1ForAccel(float accel_prev, float max_jerk, float T1);
    inline float computeT2(float T1, float T3, float accel_prev, float vel_prev, float vel_setpoint, float max_jerk);
    inline float computeT2(float T123, float T1, float T3);
    inline float computeT3(float T1, float accel_prev, float max_jerk);

    inline void integrateT(float dt, float jerk, float accel_prev, float vel_prev, float pos_prev,
                   float &accel_out, float &vel_out, float &pos_out);

    /* Inputs */
    float _vel_sp{0.0f};
    float _dt = 1.f;

    /* Constraints */
    float _max_jerk = 22.f;
    float _max_accel = 8.f;
    float _max_vel = 6.f;

    /* State (previous setpoints) */
    float _jerk = 0.f;
    float _accel = 0.f;
    float _vel = 0.f;
    float _pos = 0.f;

    float _max_jerk_T1 = 0.f; 

    /* Duration of each phase */
    float _T1 = 0.f; 
    float _T2 = 0.f; 
    float _T3 = 0.f; 

    static constexpr float max_pos_err = 1.f; 
};