statemachine.h

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#pragma once
 
#include <franka/robot_state.h>
#include <franka_gazebo/joint.h>
 
#include <ros/ros.h>
#include <boost_sml/sml.hpp>
#include <map>
#include <memory>
#include <string>
 
namespace franka_gazebo {
 
using JointMap = std::map<std::string, std::shared_ptr<Joint>>;
 
// States
struct Idle {};
struct Move {};
struct UserStopped {};
 
// Events
struct ErrorRecovery {};
struct SwitchControl {};
struct UserStop {
  bool pressed;
};
 
// Guards
auto contains = [](const auto& haystack, const auto& needle) {
  return haystack.find(needle) != std::string::npos;
};
auto isPressed = [](const UserStop& event) { return event.pressed; };
auto isReleased = [](const UserStop& event, const JointMap& joints) { return not event.pressed; };
auto isStarting = [](const SwitchControl& event, const JointMap& joints) {
  for (auto& joint : joints) {
    if (contains(joint.first, "_finger_joint")) {
      continue;
    }
    if (joint.second->control_method) {
      return true;
    }
  }
  return false;
};
auto isStopping = [](const SwitchControl& event, const JointMap& joints) {
  return not isStarting(event, joints);
};
 
// Actions
auto start = [](franka::RobotState& state) { state.robot_mode = franka::RobotMode::kMove; };
auto idle = [](franka::RobotState& state) { state.robot_mode = franka::RobotMode::kIdle; };
auto stop = [](franka::RobotState& state, JointMap& joints) {
  ROS_WARN("User stop pressed, stopping robot");
  state.robot_mode = franka::RobotMode::kUserStopped;
  state.q_d = state.q;
  state.dq_d = {0};
  state.ddq_d = {0};
 
  for (auto& joint : joints) {
    if (contains(joint.first, "_finger_joint")) {
      continue;
    }
    joint.second->stop_position = joint.second->position;
    joint.second->desired_position = joint.second->position;
    joint.second->desired_velocity = 0;
  }
};
 
struct StateMachine {
  auto operator()() const {
    using namespace boost::sml;
    return make_transition_table(
        // clang-format off
       *state<Idle>        + event<SwitchControl>[isStarting] / start = state<Move>,
        state<Idle>        + event<UserStop>[isPressed]       / stop  = state<UserStopped>,
        state<Idle>        + event<ErrorRecovery>             / start = state<Move>,
        state<Move>        + event<SwitchControl>[isStopping] / idle  = state<Idle>,
        state<Move>        + event<UserStop>[isPressed]       / stop  = state<UserStopped>,
        state<UserStopped> + event<UserStop>[isReleased]      / idle  = state<Idle>
        // clang-format on
    );
  }
};
}  // namespace franka_gazebo