wip, effort_group_position_controller

Signed-off-by: Karsten Knese <[email protected]>

effort_controllers/CMakeLists.txt

@@ -12,16 +12,21 @@ endif()
 
 # find dependencies
 find_package(ament_cmake REQUIRED)
+find_package(angles REQUIRED)
+find_package(control_toolbox REQUIRED)
 find_package(forward_command_controller REQUIRED)
 find_package(pluginlib REQUIRED)
 find_package(rclcpp REQUIRED)
 
 add_library(effort_controllers
   SHARED
   src/joint_group_effort_controller.cpp
+  src/joint_group_position_controller.cpp
 )
 target_include_directories(effort_controllers PRIVATE include)
 ament_target_dependencies(effort_controllers
+  angles
+  control_toolbox
   forward_command_controller
   pluginlib
   rclcpp

effort_controllers/effort_controllers_plugins.xml

@@ -4,4 +4,9 @@
       The joint effort controller commands a group of joints through the effort interface
     </description>
   </class>
+  <class name="effort_controllers/JointGroupPositionController" type="effort_controllers::JointGroupPositionController" base_class_type="controller_interface::ControllerInterface">
+    <description>
+      The joint position controller commands a group of joints through the effort interface
+    </description>
+  </class>
 </library>

effort_controllers/include/effort_controllers/joint_group_position_controller.hpp

@@ -0,0 +1,74 @@
+// Copyright 2020 PAL Robotics S.L.
+//
+// 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.
+
+#ifndef EFFORT_CONTROLLERS__JOINT_GROUP_POSITION_CONTROLLER_HPP_
+#define EFFORT_CONTROLLERS__JOINT_GROUP_POSITION_CONTROLLER_HPP_
+
+#include <string>
+
+#include "control_toolbox/pid.hpp"
+#include "forward_command_controller/forward_command_controller.hpp"
+#include "effort_controllers/visibility_control.h"
+
+namespace effort_controllers
+{
+
+/**
+ * \brief Forward command controller for a set of effort controlled joints (linear or angular).
+ *
+ * This class forwards the commanded efforts down to a set of joints.
+ *
+ * \param joints Names of the joints to control.
+ *
+ * Subscribes to:
+ * - \b command (std_msgs::msg::Float64MultiArray) : The effort commands to apply.
+ */
+class JointGroupPositionController : public forward_command_controller::ForwardCommandController
+{
+public:
+  EFFORT_CONTROLLERS_PUBLIC
+  JointGroupPositionController();
+
+  EFFORT_CONTROLLERS_PUBLIC
+  controller_interface::return_type
+  init(const std::string & controller_name) override;
+
+  EFFORT_CONTROLLERS_PUBLIC
+  controller_interface::InterfaceConfiguration
+  state_interface_configuration() const override;
+
+  EFFORT_CONTROLLERS_PUBLIC
+  CallbackReturn
+  on_configure(const rclcpp_lifecycle::State & previous_state) override;
+
+  EFFORT_CONTROLLERS_PUBLIC
+  CallbackReturn
+  on_activate(const rclcpp_lifecycle::State & previous_state) override;
+
+  EFFORT_CONTROLLERS_PUBLIC
+  CallbackReturn
+  on_deactivate(const rclcpp_lifecycle::State & previous_state) override;
+
+  EFFORT_CONTROLLERS_PUBLIC
+  controller_interface::return_type
+  update() override;
+
+private:
+  std::vector<control_toolbox::Pid> pids_;
+  std::chrono::time_point<std::chrono::system_clock> t0;
+};
+
+}  // namespace effort_controllers
+
+#endif  // EFFORT_CONTROLLERS__JOINT_GROUP_POSITION_CONTROLLER_HPP_

effort_controllers/package.xml

@@ -10,6 +10,8 @@
 
   <buildtool_depend>ament_cmake</buildtool_depend>
 
+  <depend>angles</depend>
+  <depend>control_toolbox</depend>
   <depend>forward_command_controller</depend>
   <depend>rclcpp</depend>
 

effort_controllers/src/joint_group_position_controller.cpp

@@ -0,0 +1,160 @@
+// Copyright 2020 PAL Robotics S.L.
+//
+// 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 <inttypes.h>
+#include <string>
+
+#include "angles/angles.h"
+#include "hardware_interface/types/hardware_interface_type_values.hpp"
+#include "effort_controllers/joint_group_position_controller.hpp"
+#include "rclcpp/logging.hpp"
+#include "rclcpp/parameter.hpp"
+
+namespace effort_controllers
+{
+using CallbackReturn = JointGroupPositionController::CallbackReturn;
+
+JointGroupPositionController::JointGroupPositionController()
+: forward_command_controller::ForwardCommandController()
+{
+  logger_name_ = "joint effort controller";
+  interface_name_ = hardware_interface::HW_IF_EFFORT;
+}
+
+controller_interface::return_type
+JointGroupPositionController::init(
+  const std::string & controller_name)
+{
+  auto ret = ForwardCommandController::init(controller_name);
+  if (ret != controller_interface::return_type::OK) {
+    return ret;
+  }
+
+  try {
+    // undeclare interface parameter used in the general forward_command_controller
+    get_node()->undeclare_parameter("interface_name");
+  } catch (const std::exception & e) {
+    fprintf(stderr, "Exception thrown during init stage with message: %s \n", e.what());
+    return controller_interface::return_type::ERROR;
+  }
+
+  return controller_interface::return_type::OK;
+}
+
+controller_interface::InterfaceConfiguration
+JointGroupPositionController::state_interface_configuration() const
+{
+  controller_interface::InterfaceConfiguration state_interfaces_config;
+  state_interfaces_config.type = controller_interface::interface_configuration_type::INDIVIDUAL;
+
+  for (const auto & joint : joint_names_) {
+    state_interfaces_config.names.push_back(joint + "/position");
+  }
+
+  return state_interfaces_config;
+}
+
+CallbackReturn JointGroupPositionController::on_configure(
+  const rclcpp_lifecycle::State & previous_state)
+{
+  auto ret = ForwardCommandController::on_configure(previous_state);
+
+  fprintf(stderr, "got %zu joints\n", joint_names_.size());
+  pids_.resize(joint_names_.size());
+  std::string gains_prefix = "gains";
+  for (auto k = 0u; k < joint_names_.size(); ++k) {
+    auto p = get_node()->get_parameter(gains_prefix + "." + joint_names_[k] + ".p").as_double();
+    auto i = get_node()->get_parameter(gains_prefix + "." + joint_names_[k] + ".i").as_double();
+    auto d = get_node()->get_parameter(gains_prefix + "." + joint_names_[k] + ".d").as_double();
+    pids_[k].initPid(p, i, d, 0.0, 0.0);
+    fprintf(stderr, "got gains for %s as (%f, %f, %f)\n", joint_names_[k].c_str(), p, i, d);
+  }
+
+  return ret;
+}
+
+CallbackReturn JointGroupPositionController::on_activate(
+  const rclcpp_lifecycle::State & /* previous_state */)
+{
+  if (command_interfaces_.size() != state_interfaces_.size()) {
+    fprintf(stderr, "state interfaces don't match with command interfaces\n");
+    return CallbackReturn::ERROR;
+  }
+  t0 = std::chrono::system_clock::now();
+
+  return CallbackReturn::SUCCESS;
+}
+
+CallbackReturn JointGroupPositionController::on_deactivate(
+  const rclcpp_lifecycle::State & previous_state)
+{
+  auto ret = ForwardCommandController::on_deactivate(previous_state);
+
+  // stop all joints
+  for (auto & command_interface : command_interfaces_) {
+    command_interface.set_value(0.0);
+  }
+
+  return ret;
+}
+
+controller_interface::return_type JointGroupPositionController::update()
+{
+  auto period = std::chrono::duration_cast<std::chrono::nanoseconds>(
+      std::chrono::system_clock::now() - t0).count();
+  t0 = std::chrono::system_clock::now();
+
+  auto joint_position_commands = *rt_command_ptr_.readFromRT();
+  // no command received yet
+  if (!joint_position_commands) {
+    return controller_interface::return_type::OK;
+  }
+
+  if (joint_position_commands->data.size() != command_interfaces_.size()) {
+    RCLCPP_ERROR_THROTTLE(
+      get_node()->get_logger(),
+      *node_->get_clock(), 1000,
+      "command size (%zu) does not match number of interfaces (%zu)",
+      joint_position_commands->data.size(), command_interfaces_.size());
+    return controller_interface::return_type::ERROR;
+  }
+
+  for(auto i = 0u; i < joint_names_.size(); ++i)
+  {
+    double command_position = joint_position_commands->data[i];
+    double current_position = state_interfaces_[i].get_value();
+    auto error = angles::shortest_angular_distance(current_position, command_position);
+
+    // Set the PID error and compute the PID command with nonuniform
+    // time step size.
+    auto commanded_effort = pids_[i].computeCommand(error, period);
+    command_interfaces_[i].set_value(commanded_effort);
+
+    // TODO(karsten1987):
+    /*
+     * enforce joint limits
+     * calculate error terms depending on joint type
+     */
+  }
+
+  t0 = std::chrono::system_clock::now();
+  return controller_interface::return_type::OK;
+}
+
+}  // namespace effort_controllers
+
+#include "pluginlib/class_list_macros.hpp"
+
+PLUGINLIB_EXPORT_CLASS(
+  effort_controllers::JointGroupPositionController, controller_interface::ControllerInterface)