cached_ik_kinematics_plugin.h

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/* Author: Mark Moll */
 
#pragma once
 
#include <moveit/kinematics_base/kinematics_base.h>
#include <moveit/kdl_kinematics_plugin/kdl_kinematics_plugin.h>
#include <moveit/robot_model/robot_model.h>
#include <tf2/LinearMath/Vector3.h>
#include <tf2/LinearMath/Quaternion.h>
#include <moveit/cached_ik_kinematics_plugin/detail/NearestNeighborsGNAT.h>
#include <boost/filesystem.hpp>
#include <unordered_map>
#include <mutex>
#include <utility>
 
namespace cached_ik_kinematics_plugin
{
class IKCache
{
public:
  struct Options
  {
    Options() : max_cache_size(5000), min_pose_distance(1.0), min_joint_config_distance(1.0), cached_ik_path("")
    {
    }
    unsigned int max_cache_size;
    double min_pose_distance;
    double min_joint_config_distance;
    std::string cached_ik_path;
  };
 
  struct Pose
  {
    Pose() = default;
    Pose(const geometry_msgs::Pose& pose);
    tf2::Vector3 position;
    tf2::Quaternion orientation;
    double distance(const Pose& pose) const;
  };
 
  using IKEntry = std::pair<std::vector<Pose>, std::vector<double>>;
 
  IKCache();
  ~IKCache();
  IKCache(const IKCache&) = delete;
 
  const IKEntry& getBestApproximateIKSolution(const Pose& pose) const;
  const IKEntry& getBestApproximateIKSolution(const std::vector<Pose>& poses) const;
  void initializeCache(const std::string& robot_id, const std::string& group_name, const std::string& cache_name,
                       const unsigned int num_joints, const Options& opts = Options());
  void updateCache(const IKEntry& nearest, const Pose& pose, const std::vector<double>& config) const;
  void updateCache(const IKEntry& nearest, const std::vector<Pose>& poses, const std::vector<double>& config) const;
  void verifyCache(kdl_kinematics_plugin::KDLKinematicsPlugin& fk) const;
 
protected:
  double configDistance2(const std::vector<double>& config1, const std::vector<double>& config2) const;
  void saveCache() const;
 
  unsigned int num_joints_;
 
  double min_pose_distance_;
  double min_config_distance2_;
  unsigned int max_cache_size_;
  boost::filesystem::path cache_file_name_;
 
  mutable std::vector<IKEntry> ik_cache_;
  mutable NearestNeighborsGNAT<IKEntry*> ik_nn_;
  mutable unsigned int last_saved_cache_size_{ 0 };
  mutable std::mutex lock_;
};
 
class IKCacheMap : public std::unordered_map<std::string, IKCache*>
{
public:
  using IKEntry = IKCache::IKEntry;
  using Pose = IKCache::Pose;
 
  IKCacheMap(const std::string& robot_description, const std::string& group_name, unsigned int num_joints);
  ~IKCacheMap();
  const IKEntry& getBestApproximateIKSolution(const std::vector<std::string>& fixed,
                                              const std::vector<std::string>& active,
                                              const std::vector<Pose>& poses) const;
  void updateCache(const IKEntry& nearest, const std::vector<std::string>& fixed,
                   const std::vector<std::string>& active, const std::vector<Pose>& poses,
                   const std::vector<double>& config);
 
protected:
  std::string getKey(const std::vector<std::string>& fixed, const std::vector<std::string>& active) const;
  std::string robot_description_;
  std::string group_name_;
  unsigned int num_joints_;
};
 
// Helper class to enable/disable initialize() methods with new/old API
// HasRobotModelApi<T>::value provides a true/false constexpr depending on KinematicsPlugin offers the new Api
// This uses SFINAE magic: https://jguegant.github.io/blogs/tech/sfinae-introduction.html
template <typename KinematicsPlugin, typename = bool>
struct HasRobotModelApi : std::false_type
{
};
 
template <typename KinematicsPlugin>
struct HasRobotModelApi<KinematicsPlugin, decltype(std::declval<KinematicsPlugin&>().initialize(
                                              std::declval<const moveit::core::RobotModel&>(), std::string(),
                                              std::string(), std::vector<std::string>(), 0.0))> : std::true_type
{
};
 
template <typename KinematicsPlugin, typename = bool>
struct HasRobotDescApi : std::false_type
{
};
 
template <typename KinematicsPlugin>
struct HasRobotDescApi<KinematicsPlugin,
                       decltype(std::declval<KinematicsPlugin&>().KinematicsPlugin::initialize(
                           std::string(), std::string(), std::string(), std::vector<std::string>(), 0.0))>
  : std::true_type
{
};
 
template <class KinematicsPlugin>
class CachedIKKinematicsPlugin : public KinematicsPlugin
{
public:
  using Pose = IKCache::Pose;
  using IKEntry = IKCache::IKEntry;
  using IKCallbackFn = kinematics::KinematicsBase::IKCallbackFn;
  using KinematicsQueryOptions = kinematics::KinematicsQueryOptions;
 
  CachedIKKinematicsPlugin();
 
  ~CachedIKKinematicsPlugin() override;
 
  // virtual methods that need to be wrapped:
 
  bool initialize(const moveit::core::RobotModel& robot_model, const std::string& group_name,
                  const std::string& base_frame, const std::vector<std::string>& tip_frames,
                  double search_discretization) override
  {
    return initializeImpl(robot_model, group_name, base_frame, tip_frames, search_discretization);
  }
 
  bool initialize(const std::string& robot_description, const std::string& group_name, const std::string& base_frame,
                  const std::string& tip_frame, double search_discretization) override
  {
    return initializeImpl(robot_description, group_name, base_frame, tip_frame, search_discretization);
  }
 
  bool getPositionIK(const geometry_msgs::Pose& ik_pose, const std::vector<double>& ik_seed_state,
                     std::vector<double>& solution, moveit_msgs::MoveItErrorCodes& error_code,
                     const KinematicsQueryOptions& options = KinematicsQueryOptions()) const override;
 
  bool searchPositionIK(const geometry_msgs::Pose& ik_pose, const std::vector<double>& ik_seed_state, double timeout,
                        std::vector<double>& solution, moveit_msgs::MoveItErrorCodes& error_code,
                        const KinematicsQueryOptions& options = KinematicsQueryOptions()) const override;
 
  bool searchPositionIK(const geometry_msgs::Pose& ik_pose, const std::vector<double>& ik_seed_state, double timeout,
                        const std::vector<double>& consistency_limits, std::vector<double>& solution,
                        moveit_msgs::MoveItErrorCodes& error_code,
                        const KinematicsQueryOptions& options = KinematicsQueryOptions()) const override;
 
  bool searchPositionIK(const geometry_msgs::Pose& ik_pose, const std::vector<double>& ik_seed_state, double timeout,
                        std::vector<double>& solution, const IKCallbackFn& solution_callback,
                        moveit_msgs::MoveItErrorCodes& error_code,
                        const KinematicsQueryOptions& options = KinematicsQueryOptions()) const override;
 
  bool searchPositionIK(const geometry_msgs::Pose& ik_pose, const std::vector<double>& ik_seed_state, double timeout,
                        const std::vector<double>& consistency_limits, std::vector<double>& solution,
                        const IKCallbackFn& solution_callback, moveit_msgs::MoveItErrorCodes& error_code,
                        const KinematicsQueryOptions& options = KinematicsQueryOptions()) const override;
 
private:
  IKCache cache_;
 
  void initCache(const std::string& robot_id, const std::string& group_name, const std::string& cache_name);
 
  /* Using templates and SFINAE magic, we can selectively enable/disable methods depending on
     availability of API in wrapped KinematicsPlugin class.
     However, as templates and virtual functions cannot be combined, we need helpers initializeImpl(). */
  template <class T = KinematicsPlugin>
  typename std::enable_if<HasRobotModelApi<T>::value, bool>::type
  initializeImpl(const moveit::core::RobotModel& robot_model, const std::string& group_name,
                 const std::string& base_frame, const std::vector<std::string>& tip_frames,
                 double search_discretization)
  {
    if (tip_frames.size() != 1)
    {
      ROS_ERROR_NAMED("cached_ik", "This solver does not support multiple tip frames");
      return false;
    }
 
    // call initialize method of wrapped class
    if (!KinematicsPlugin::initialize(robot_model, group_name, base_frame, tip_frames, search_discretization))
      return false;
    initCache(robot_model.getName(), group_name, base_frame + tip_frames[0]);
    return true;
  }
 
  template <class T = KinematicsPlugin>
  typename std::enable_if<!HasRobotModelApi<T>::value, bool>::type
  initializeImpl(const moveit::core::RobotModel& /*unused*/, const std::string& /*unused*/,
                 const std::string& /*unused*/, const std::vector<std::string>& /*unused*/, double /*unused*/)
  {
    return false;  // API not supported
  }
 
  template <class T = KinematicsPlugin>
  typename std::enable_if<HasRobotDescApi<T>::value, bool>::type
  initializeImpl(const std::string& robot_description, const std::string& group_name, const std::string& base_frame,
                 const std::string& tip_frame, double search_discretization)
  {
    // call initialize method of wrapped class
    if (!KinematicsPlugin::initialize(robot_description, group_name, base_frame, tip_frame, search_discretization))
      return false;
    initCache(robot_description, group_name, base_frame + tip_frame);
    return true;
  }
 
  template <class T = KinematicsPlugin>
  typename std::enable_if<!HasRobotDescApi<T>::value, bool>::type
  initializeImpl(const std::string& /*unused*/, const std::string& /*unused*/, const std::string& /*unused*/,
                 const std::string& /*unused*/, double /*unused*/)
  {
    return false;  // API not supported
  }
};
 
template <class KinematicsPlugin>
class CachedMultiTipIKKinematicsPlugin : public CachedIKKinematicsPlugin<KinematicsPlugin>
{
public:
  using Pose = IKCache::Pose;
  using IKEntry = IKCache::IKEntry;
  using IKCallbackFn = kinematics::KinematicsBase::IKCallbackFn;
  using KinematicsQueryOptions = kinematics::KinematicsQueryOptions;
 
  bool initialize(const moveit::core::RobotModel& robot_model, const std::string& group_name,
                  const std::string& base_frame, const std::vector<std::string>& tip_frames,
                  double search_discretization) override;
 
  bool initialize(const std::string& robot_description, const std::string& group_name, const std::string& base_frame,
                  const std::vector<std::string>& tip_frames, double search_discretization) override;
 
  bool searchPositionIK(const std::vector<geometry_msgs::Pose>& ik_poses, const std::vector<double>& ik_seed_state,
                        double timeout, const std::vector<double>& consistency_limits, std::vector<double>& solution,
                        const IKCallbackFn& solution_callback, moveit_msgs::MoveItErrorCodes& error_code,
                        const KinematicsQueryOptions& options = KinematicsQueryOptions(),
                        const moveit::core::RobotState* context_state = nullptr) const override;
};
}  // namespace cached_ik_kinematics_plugin
 
#include "cached_ik_kinematics_plugin-inl.h"