ROS Resources: Documentation | Support | Discussion Forum | Index | Service Status | ros @ Robotics Stack Exchange
Ask Your Question

Sahand_Rez's profile - activity

2021-12-27 02:19:50 -0500 received badge  Favorite Question (source)
2020-04-03 03:00:46 -0500 received badge  Taxonomist
2020-03-20 10:15:32 -0500 received badge  Famous Question (source)
2019-07-18 10:07:54 -0500 received badge  Famous Question (source)
2019-03-07 00:58:33 -0500 received badge  Notable Question (source)
2019-01-07 18:41:24 -0500 received badge  Famous Question (source)
2019-01-07 18:41:24 -0500 received badge  Notable Question (source)
2018-10-12 03:21:37 -0500 received badge  Notable Question (source)
2018-08-17 09:44:34 -0500 received badge  Popular Question (source)
2018-08-16 12:45:53 -0500 asked a question Gazebo sends wrong velocities when using joint effort controller

Gazebo sends wrong velocities when using joint effort controller Hello Everyone, I am working with Kinova Jaco 2 arm i

2018-08-07 05:41:34 -0500 received badge  Notable Question (source)
2018-07-03 00:59:46 -0500 received badge  Popular Question (source)
2018-06-18 08:10:17 -0500 received badge  Popular Question (source)
2018-06-13 04:37:52 -0500 received badge  Popular Question (source)
2018-06-11 15:35:19 -0500 asked a question How to give MoveIt! waypoints in joint space?

How to give MoveIt! waypoints in joint space? Hi, I have a manipulator which can be commanded through moveit_commander

2018-05-31 07:07:09 -0500 received badge  Enthusiast
2018-05-28 15:20:24 -0500 edited answer Callback function not updating values (Rospy)

Hi, I was having the exact same problem. I was able to find a work around. Just put a rospy.sleep(0.1) at the very begi

2018-05-28 15:16:45 -0500 answered a question Callback function not updating values (Rospy)

Hi, I was having the exact same problem. I was able to find a work around. Just put a rospy.sleep(0.01) at the very beg

2018-05-24 10:24:46 -0500 marked best answer Accessing previous estimated joint states of a robot

Hi,

I am new to ROS and I am trying to implement a Kalman filter for estimating the joints velocity and acceleration of a robotic manipulator.

The angular position of each joint is published to the topic /j2n6s300/joint_states, and the 'estimate_joint_states' node subscribes to that topic to get the data. Now I want the estimation to be done within 'estimate_joint_states' node and published to another topic /j2n6s300/estimated_joint_states. However, in each iteration of the Kalman filter, the previous estimates of the system (angular position, velocity and acceleration) are required. What is the "ROS way" to access that data? Can the node estimate_joint_states subscribe to /j2n6s300/estimated_joint_states (the topic in which it is also publishing) and then use its data in the next time step? Or is there a better way to access the previous estimated states?

I know it is possible to write a node which subscribes and publishes at the same time. But is it also possible to implement a node which subscribes to two topics and publishes in to one of them?

I am implementing in python by the way.

Thanks in advance!

2018-05-24 10:24:46 -0500 received badge  Scholar (source)
2018-05-24 10:24:41 -0500 received badge  Supporter (source)
2018-05-24 10:24:07 -0500 received badge  Editor (source)
2018-05-24 10:24:07 -0500 edited question How to get control outputs from ROS_Control?

How to get control outputs from ROS_Control? Hello, I am working on the Kinova Jaco2 arm. They have provided a ROS pac

2018-05-24 10:23:27 -0500 asked a question How to get control outputs from ROS_Control?

How to get control outputs from ROS_Control? Hello, I am working on the Kinova Jaco2 arm. They have provided a ROS pac

2018-04-07 14:42:00 -0500 commented question Accessing previous estimated joint states of a robot

Thanks a lot for pointing that out! I wasn't at all thinking about something this simple.

2018-04-07 13:53:42 -0500 edited question Accessing previous estimated joint states of a robot

Accessing previous estimated joint states of a robot Hi, I am new to ROS and I am trying to implement a Kalman filter f

2018-04-07 13:52:31 -0500 commented question Accessing previous estimated joint states of a robot

So this is what I wasn't quite sure of. How can I keep a local variable around in a node? the state_estimator class has

2018-04-07 13:50:53 -0500 commented question Accessing previous estimated joint states of a robot

So this is what I wasn't quite sure of. How can I keep a local variable around in a node? My class looks like this:

2018-04-07 13:23:45 -0500 asked a question Accessing previous estimated joint states of a robot

Accessing previous estimated joint states of a robot Hi, I am new to ROS and I am trying to implement a Kalman filter f