I want to control and drive a real 6-DOF robotic arm.
I have setup my Moveit configuration files using joint_trajectory_controller and MoveItSimpleControllerManager. Here is my moveit controllers.yaml file:
controller_list:
- name: /nymblebot/position_trajectory_controller
action_ns: follow_joint_trajectory
type: FollowJointTrajectory
default: true
joints:
- base_swivel
- arm_joint
- elbow_joint
- wrist_pitch
- wrist_yaw
- wrist_roll
Then I have setup my ros_control files along with hardware interfaces. Here is my ros_control hardware_controllers.yaml file:
generic_hw_control_loop:
loop_hz: 30
cycle_time_error_threshold: 0.01
# Settings for ros_control hardware interface
nymble_hw_interface:
joints:
- base_swivel
- arm_joint
- elbow_joint
- wrist_pitch
- wrist_yaw
- wrist_roll
# Joint Trajectory Controller -------------------------------
# For detailed explanations of parameter see http://wiki.ros.org/joint_trajectory_controller
position_trajectory_controller:
type: position_controllers/JointTrajectoryController
# These joints can likely just be copied from the hardware_interface list above
joints:
- base_swivel
- arm_joint
- elbow_joint
- wrist_pitch
- wrist_yaw
- wrist_roll
# Publish all joint states ----------------------------------
# Creates the /joint_states topic necessary in ROS
joint_state_controller:
type: joint_state_controller/JointStateController
publish_rate: 50
My control interface is based on Adolfo's ROSCON'14 talk. In my main executable, I instantiate a hardware interface class of my robot. Then I instantiate a control_loop class which has read(), write() as member functions and pulls info out from ROS parameter server.
Also I form an instance of the controller manager. Following this I have my main control loop which proceeds as:
- read() 2.update() 3.write()
Unfortunately the process crashes soon after the 2.update() command. And only the joint_state_controller gets loaded.
Started ['joint_state_controller'] successfully
Traceback (most recent call last):
File "/opt/ros/indigo/lib/controller_manager/controller_manager", line 65, in <module>
controller_manager_interface.start_controller(c)
File "/opt/ros/indigo/lib/python2.7/dist-packages/controller_manager/controller_manager_interface.py", line 86, in start_controller
return start_stop_controllers([name], True)
File "/opt/ros/indigo/lib/python2.7/dist-packages/controller_manager/controller_manager_interface.py", line 107, in start_stop_controllers
resp = s.call(SwitchControllerRequest(start, stop, strictness))
File "/opt/ros/indigo/lib/python2.7/dist-packages/rospy/impl/tcpros_service.py", line 525, in call
raise ServiceException("transport error completing service call: %s"%(str(e)))
rospy.service.ServiceException: transport error completing service call: unable to receive data from sender, check sender's logs for details
[nymblebot/nymblebot_hardware_interface-8] process has died [pid 8763, exit code -11, cmd /home/rohin/catkin_ws/devel/lib/hardware/nymble_hw_control_loop __name:=nymblebot_hardware_interface __log:=/home/rohin/.ros/log/4856bd5a-41c5-11e6-b1dc-20689d39eac5/nymblebot-nymblebot_hardware_interface-8.log].
log file: /home/rohin/.ros/log/4856bd5a-41c5-11e6-b1dc-20689d39eac5/nymblebot-nymblebot_hardware_interface-8*.log
[nymblebot/ros_control_controller_manager-7] process has died [pid 8755, exit code 1, cmd /opt/ros/indigo/lib/controller_manager/controller_manager spawn joint_state_controller position_trajectory_controller __name:=ros_control_controller_manager __log:=/home/rohin/.ros/log/4856bd5a-41c5-11e6-b1dc-20689d39eac5/nymblebot-ros_control_controller_manager-7.log].
log file: /home/rohin/.ros/log/4856bd5a-41c5-11e6-b1dc-20689d39eac5/nymblebot-ros_control_controller_manager-7*.log
For reference here is my main control loop in my executable:
int main(int argc, char **argv)
{
// Setup ROS
ros::init(argc, argv, "nymblebot_hw_interface");
ros::NodeHandle n;
// NOTE: We run the ROS loop in a separate thread as external calls such
// as service callbacks to load controllers can block the (main) control loop
ros::AsyncSpinner spinner(2);
spinner.start();
// Create the hardware interface specific to your robot
boost::shared_ptr<NymbleHW> nymble_hw_interface (new NymbleHW(n));
//nymble_hw_interface->init();
// Start the control loop
Nymble_HW_Loop control_loop(n, nymble_hw_interface);
control_loop.init();
boost::shared_ptr<controller_manager::ControllerManager> controller_manager_;
// Create the controller manager
controller_manager_.reset(new controller_manager::ControllerManager(nymble_hw_interface.get(), n));
ros::Rate loop_rate(50); // Hz
ROS_INFO("Controller node initialized.");
ROS_INFO("Namespace: %s", n.getNamespace().c_str());
// Joint state publisher
control_loop.jointStatePub = n.advertise<sensor_msgs::JointState>("nymblebot_joint_states", 1000);
// Goal joint state publisher
control_loop.goalJointStatePub = n.advertise<sensor_msgs::JointState>("nymblebot_goal_joint_states", 1000);
// Command Publisher
control_loop.serial_command = n.advertise<std_msgs::Float64MultiArray>("/ros_serial/command",1000) ;
// Subscriber to encoder feedback
ros::Subscriber readEncoderFeedback = n.subscribe("ros_serial/encoder_feedback", 1000, encoderCallback);
// Main program loop
ros::Time prevTime = ros::Time::now();
ros::Duration(10).sleep(); // sleep for half a second
while (ros::ok())
{
const ros::Time currentTime = ros::Time::now();
ROS_INFO("Current time (ms): %g", (currentTime.toNSec())/pow(10.0, 6));
ROS_INFO("Period (ms): %g", (currentTime - prevTime).toNSec()/pow(10.0, 6));
control_loop.read();
ROS_INFO("Loop started. Values read.");
//control_loop.controller_manager_->update(currentTime, currentTime - prevTime);
controller_manager_->update(currentTime, currentTime - prevTime);
ros::Duration(5).sleep(); // sleep
ROS_INFO("Controller manager updated.");
if (control_loop.getPositionControlEnabled())
control_loop.write();
ROS_INFO("Values written to joints");
prevTime = currentTime;
ros::spinOnce();
loop_rate.sleep();
}
ros::waitForShutdown();
return 0;
}
Originally posted by rohin on ROS Answers with karma: 99 on 2016-07-04
Post score: 0
