TwistMux Node dies in ROS2 Jazzy

[BrainBoxTayo]

[twist_mux-10] terminate called after throwing an instance of 'twist_mux::ParamsHelperException'
[twist_mux-10] what(): could not load parameter 'use_stamped'. (namespace: /)

[ERROR] [twist_mux-10]: process has died [pid 188290, exit code -6, cmd '/opt/ros/jazzy/lib/twist_mux/twist_mux --ros-args --params-file /tmp/launch_params_gvyag67m --params-file /home/brainboxtayo/bumperbot_ws/install/bumperbot_controller/share/bumperbot_controller/config/twist_mux_locks.yaml --params-file /opt/ros/jazzy/share/twist_mux/config/twist_mux_topics.yaml -r /cmd_vel_out:=bumperbot_controller/cmd_vel_unstamped'].

[BrainBoxTayo]

Had to build from source, I made the following changes:

twist_mux.cpp
void TwistMux::init()
{
  // Get use stamped parameter
  bool use_stamped = false; //changed here, since params are not working
  auto nh = std::shared_ptr<rclcpp::Node>(this, [](rclcpp::Node *) {});
  // fetch_param(nh, "use_stamped", use_stamped);

  /// Get topics and locks:
  if(use_stamped)
  {
    velocity_stamped_hs_ = std::make_shared<velocity_stamped_topic_container>();
    getTopicHandles("topics", *velocity_stamped_hs_);
  }
  else
  {
    velocity_hs_ = std::make_shared<velocity_topic_container>();
    getTopicHandles("topics", *velocity_hs_);
  }
  lock_hs_ = std::make_shared<lock_topic_container>();
  getTopicHandles("locks", *lock_hs_);

  /// Publisher for output topic:
  if(use_stamped)
  {
    cmd_pub_stamped_ =
      this->create_publisher<geometry_msgs::msg::TwistStamped>(
        "cmd_vel_out",
        rclcpp::QoS(rclcpp::KeepLast(1)));
  }
  else
  {
    cmd_pub_ =
      this->create_publisher<geometry_msgs::msg::Twist>(
      "cmd_vel_out",
      rclcpp::QoS(rclcpp::KeepLast(1)));
  }

---

twist_marker.cpp
class TwistMarkerPublisher : public rclcpp::Node
{
public:
  TwistMarkerPublisher()
  : Node("twist_marker")
  {
    std::string frame_id;
    double scale;
    bool use_stamped = false; //made use_stamped a boolean value for the if check
    double z;

    this->declare_parameter("frame_id", "base_footprint");
    this->declare_parameter("scale", 1.0);
    // this->declare_parameter("use_stamped", false); //changed this line
    this->declare_parameter("vertical_position", 2.0);

    this->get_parameter<std::string>("frame_id", frame_id);
    this->get_parameter<double>("scale", scale);
    // this->get_parameter<bool>("use_stamped", use_stamped); //and this
    this->get_parameter<double>("vertical_position", z);

    marker_ = std::make_shared<TwistMarker>(frame_id, scale, z);

    if (use_stamped)
    {
      sub_stamped_ = this->create_subscription<geometry_msgs::msg::TwistStamped>(
        "twist", rclcpp::SystemDefaultsQoS(),
        std::bind(&TwistMarkerPublisher::callback_stamped, this, std::placeholders::_1));
    }
    else
    {
      sub_ = this->create_subscription<geometry_msgs::msg::Twist>(
        "twist", rclcpp::SystemDefaultsQoS(),
        std::bind(&TwistMarkerPublisher::callback, this, std::placeholders::_1));
    }

    pub_ =
      this->create_publisher<visualization_msgs::msg::Marker>(
      "marker",
      rclcpp::QoS(rclcpp::KeepLast(1)));
  }

---

include/twist_mux/twist_mux_diagnostics_status.hpp
#include <memory>

namespace twist_mux
{
struct TwistMuxDiagnosticsStatus
{
  typedef std::shared_ptr<TwistMuxDiagnosticsStatus> Ptr;
  typedef std::shared_ptr<const TwistMuxDiagnosticsStatus> ConstPtr;

  double reading_age;
  rclcpp::Time last_loop_update;
  double main_loop_time;

  LockTopicHandle::priority_type priority;

  bool use_stamped;

  std::shared_ptr<TwistMux::velocity_topic_container> velocity_hs;
  std::shared_ptr<TwistMux::velocity_stamped_topic_container> velocity_stamped_hs;
  std::shared_ptr<TwistMux::lock_topic_container> lock_hs;

  TwistMuxDiagnosticsStatus()
  : reading_age(0),
    last_loop_update(rclcpp::Clock().now()),
    main_loop_time(0),
    priority(0),
    use_stamped(false) //changed this line
  {
    velocity_hs = std::make_shared<TwistMux::velocity_topic_container>();
    velocity_stamped_hs = std::make_shared<TwistMux::velocity_stamped_topic_container>();
    lock_hs = std::make_shared<TwistMux::lock_topic_container>();
  }
};

[TWALL9]

Hey @BrainBoxTayo I see that this is a closed issue that you addressed by removing the use_stamped parameter entirely. You could have also added that parameter to your twist_mux_params.yaml file like so

twist_mux:
  ros__parameters:
    use_stamped: true
    topics:

or even in the launch file that starts twist_mux like so:

twist_mux = Node(
        package='twist_mux',
        executable='twist_mux',
        parameters=[twist_mux_params, {'use_sim_time': use_sim_time}, {'use_stamped': True}]
)

I'm also working on setting the param to default to false in this PR: #55

[BrainBoxTayo]

Hi @TWALL9 , that was the approach I took first. But for some reason it wasn't working. Maybe I had a syntax issue. Thanks so much though. This would come in handy to people facing the same error.
Why do you think the use_stamped param kills the node?

[TWALL9]

The node is dying because the fetch_param() method is throwing an exception which isn't being handled in init(). The exception is that the use_stamped parameter isn't being found, and because it's required to have a value further down in init(). Trouble is that use_stamped is not being declared as a parameter, but the node expects it to be there, set by whatever is launching twist_mux. So the node is looking for a parameter that the user is just supposed to know needs to be set, but without declaring that this parameter needs to exist in the first place. I guess an analogy is if you're in a restaurant and order a glass of water from a waiter. Instead of asking if you'd like ice with your water, the waiter expected you to order the water with or without ice and because you never said you did or didn't want ice, the waiter simply explodes.

…

On Sun, Dec 29, 2024, 04:27 Akanbi-Bello Temitayo ***@***.***> wrote: Hi @TWALL9 <https://github.com/TWALL9> , that was the approach I took first. But for some reason it wasn't working. Maybe I had a syntax issue. Thanks so much though. This would come in handy to people facing the same error. Why do you think the use_stamped param kills the node? — Reply to this email directly, view it on GitHub <#53 (comment)>, or unsubscribe <https://github.com/notifications/unsubscribe-auth/ABPG3SELXFUKK2TEDY6HGPT2H7TETAVCNFSM6AAAAABRWN4FSGVHI2DSMVQWIX3LMV43OSLTON2WKQ3PNVWWK3TUHMZDKNRUG4YDSMBWGQ> . You are receiving this because you were mentioned.Message ID: ***@***.***>

[BrainBoxTayo]

Ahh ok thank you!