Questions tagged [robot-model]

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Define system forward dynamics with sympy

I would like to model the dynamics of a robot via the usual discretized system of equations $$ x_{k+1} = f(x_k, u_k) \qquad x\in\mathbb{R}^{n_x}, \quad f:\mathbb{R}^{n_x}\times\mathbb{R}^{n_u} \to \...
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1 answer
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Peter Corke Robotics Matlab Toolbox the problem of inverse dynamics in the Franka Emika Panda model

I have the following question about the Franka Emika Panda dynamic model. In case I perform the solution of the inverse dynamics problem using Robotics Toolbox (Peter Corke) I get different results ...
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2 answers
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Generate robot model for openrave

Is there another way to generate a collada model to work with openrave other than converting an URDF file with ROS' collada_urdf software? The problem I'm encountering is with the setup needed to use ...
2 votes
1 answer
92 views

Modelling/Theory for Quadraped Robot Leg Example

I have been working on attempting to replicate the following robot developed by some MIT graduates. https://dspace.mit.edu/handle/1721.1/98948 Presently, I am trying to work out the model for a single ...
1 vote
0 answers
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Alternative Landmark Observation Model for Fast SLAM using 3D Point Clouds

I am in the process of implementing a Fast-SLAM Algorithm as it is described in Chapter 13 of Probabilistic Robotics by Thrun, Burgard and Fox or this publication by Thrun, Koller and Wegbreit however,...
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1 answer
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Steering wheel angle control

I am working on an autonomous vehicle's control, specifically the steering angle control. Knowing that I used kinematic bicycle model, my questions are: How do I choose the actuator for my steering ...
1 vote
0 answers
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Ideas on how to create kinematic model of skid-steered rocker bogie mobile robot

I'm trying to derive the inverse kinematics of a skid-steered mobile robot with rocker-bogie mechanism. I learned how to derive the kinematics via transformation matrices as per "Kinematic ...
3 votes
1 answer
319 views

DC motor modelling with Bond Graph

I am trying to construct an equation that describes the output torque as a function of lambda and omega I have obtained the following bond graph but I am unsure of how to proceed.
1 vote
1 answer
2k views

Denavit-hartenberg parameters sign 6-DOF

Trying to understand how does the Denavit-Hartenberg work. While I understood how is the table constructed, I however don't understand how are the signs for the orientation parameters (theta, joint ...
2 votes
1 answer
404 views

URDF for a real robot

I have been making robots in ROS/Gazebo simulation before, which makes use of the URDF to understand the robot model, different frames and transformations. For a real robot, do I need a URDF as well? ...
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1 answer
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DH Parameters of a 2 DOF RP Robot

How can I determine the DH parameters of the robot shown in the figure ? As i know, the z axis should show the rotation axis for rotary joints and direction of extension for prismatic joints, so the ...
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1 answer
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Choose the structure of the dynamic model for the generalized equations of motion of the robot

I ask the robotics specialists for help as I am a little confused. I have two subsystems which are shown in the picture below: One of them is a system of stable and controlled differential equations ...
1 vote
1 answer
236 views

4 Axis Gimbal Nodal Robot DH Parameters

I'm working on a robot gimbal where there are 4 revolute joints (4th axis for gimbal lock, reducing inertia etc). The robot is nodal such that all axes have the same nodal point and rotating any axes ...
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2 answers
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Webots to URDF Model Converter

Is there any existing work out there on a converter that allows generating URDF from Webots models? I´d be interested in anything useful for that task (also partial implementations, hints, etc.). ...
1 vote
2 answers
154 views

Equations of motion in matrix form and energy consumption

I am working on Lagrangian derived high-dimensional motion equations for a robot in matrix form. The structure of such an equation is known: $M(q)\ddot{q}+C(q,\dot{q})\dot{q}+G(q)=0$ In here, $M(q)$, $...
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Spherical Parallel Manipulator Lagrangian problem

I faced a very serious problem and I urgently need the help of specialists in robotics, mechanics, physics and mathematics. I am trying to derive equations of motion from the Lagrangian of a spherical ...
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ICP results as command in odometry motion model

im going through the odometry motion model proposed by Thurn in Probabilistic Robotics famous book and i have some questions concerning the kind of command that we can use. I will explain more my ...
1 vote
3 answers
103 views

Occupancy grid maps

Why do we take probabilistic approch to model the environment for robots in occupancy grid maps.The assumption is always taken that each cell on the grid map is either free or occupied.So why have ...
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1 answer
235 views

Estimation of pitch, roll, yaw angles: synthesis of an observer or IMU?

Dear Robotics Specialists, I want to contact you for advice. I am developing a control system for complex parallel mechanisms like what I presented in this thread. Formulas for calculating the ...
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1 answer
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My robot keeps getting saved as one cylinder leaving out the bottom cube

I created a robot in the model editor that is made up of a cube and a cylinder with a revolute joint between them but after saving it and inserting another instance into the world, I only get the ...
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1 answer
112 views

How to simulate a quadcopter using robotics simulator?

I am building my own autonomous quadcopter. I wish to simulate it using V-REP/Gazebo in order to tune the flight controller. I see that there are inbuilt models but they have properties(physical ...
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1 answer
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Forward kinematics of spherical parallel manipulators with revolute joints

I found an article that can help in my investigations. Forward kinematics of spherical parallel manipulators with revolute joints The problem is solved for the following system of vectors, which is ...
0 votes
1 answer
71 views

Why are the angular velocities of concentrated masses in Lagrangian independent?

There is an ordinary linear three-mass system. If we write its Lagrangian, we get the following equation. where $W_k$ and $W_n$ - kinetic and potential energy. To find the moment of rotation of the ...
1 vote
2 answers
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Dynamic models of parallel robots in the form of multi-mass systems with stiffness coefficients

I want to develop a dynamic model of a parallel robot for control tasks. It is known that equations of motion based on Lagrange equations can be transformed into a state space and use such a model. ...
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2 answers
558 views

Model of two link rigid manipulator

I am working on parameter estimation of a rigid two-link manipulator as shown in the picture below. Unlike the cylindrical links shown in the above image, my robot has links of oval shape. So the ...
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1 answer
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Problem with MoveGroupInterface::getRobotModel() providing only const version

I'm trying to get my own instance of JointModelGroup from code equivalent to this: ...
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1 answer
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Second instance of robot model for constraints planning

Hi every one! I'm working on a dual_arm planner to use 2 UR-10 for manipulation. I'm coding it in c++, but i'm still learning every day about coding, so please be gentle :) Using ROS Indigo on Ubuntu ...
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5 answers
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How can I use the navigation stack on a carlike robot?

AFAIK the navigation stack in its current state does not work for a carlike robot. The last time I checked, base_local_planner required the robot to be able to turn in place. Would I have to implement ...
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1 answer
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Confused about Xacro and URDF

Hey together, I am a little bit confused about the use case of xacro and urdf. I my case I have an robot equipped with 3 laserscanner and modeled a urdf file for it following the build your URDF ...
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1 answer
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footstep_planner model problem

Hi, i'm new in ROS. I'm trying to start with footstep_planner. According footstep_planner and Getting-Started tutorials install all packages that we need. Then i'm running ...
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1 answer
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Dynamic Robot Model Implementation

I'm wondering if anyone can offer advice on how to approximate a non-rigid robot model. I'm implementing a model of a 3 DOF arm for a university independent study that uses a rollable prestressed tube ...
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1 answer
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Pioneer3-AT Rviz/urdf model

Hi everyone! I am running a SLAM simulation using a Pioneer3-AT and it would be usefull if I had the pioneer's model on Rviz. That is, is there a way or a place where I can get a model of the P3-AT ...
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1 answer
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Using osg (OpenSceneGraph) models in rviz?

I am trying to show meshes in rviz and the mesh is originally an OpenSceneGraph model (.osg). My previous conversion pipeline was to use osgconv to convert to 3ds and wings3d to convert to collada dae....
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1 answer
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Compile problem in robot_model (catkin_package)

Hello, When I try to compile the robot_model it shows that: " CMake Error at CMakeLists.txt:6 (catkin_package): Unknown CMake command "catkin_package". " I am using Ubuntu 12.04 &...
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problem in building package 3d_navigation

Hi, I am using ros-diamondback with ubuntu version 10.10. The package '3d_navigation' has dependency on stack 'pr2_mechanism'. While trying to built this stack, it needs 'urdf_interface' from stack '...
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1 answer
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How to use navigation stack in simulation using .dae and rviz

To use and learn navigation stack, I'd like to simulate 2D navigation (path planning and collision avoidance) using a robot model(e.g. PR2.dae) and rviz. Are there any tutorials for that? What are ...
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1 answer
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How to modify the turtlebot robot model in rviz?

Hi, I have remodeled my turtlebot with additional hardware to increase the height of the kinect location. I would like to model the same in rviz. I want to know which urdf file i should edit in order ...
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1 answer
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How to fix SIA10D ROS industrial robot loading model fail in RViz?

I followed ROS-Industrial Tutorial. I run: roslaunch sia10d_mesh_arm_navigation planning_scene_warehouse_viewer_sia10d_mesh.launch And get partly loaded model of ...
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1 answer
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robot description in turtlebot

Hi, I am trying to push everithing related to my robot under the name of the robot, but when it comes to the topic robot_description I can't, the description keeps the original tree for the transform ...
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1 answer
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How to debug gazebo

Hi all, I'm migrating to electric and i have some issues setting my gazebo simulation on, i can launch gazebo and my .world map and i seem to works fine (i had to make some changes to remove some ...
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2 answers
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Is there a list of free available robot models for gazebo?

Hi, I wanted to know if there is a list of free available robots to play with in gazebo; such as turtlebot, PR2, erratic-robot? Maybe there are some models for the Pioneer, Care-O-bot, Roomba, ...
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1 answer
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3d mesh model of robot based on joint states

I want to determine the projection of the robot arms (PR2) onto its cameras so that I can mask these regions out of the images. Has anyone done this before? I see some relevant code in the ...
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3 answers
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Multiple visual entries in urdf

Is it possible to have multiple visual entries in an urdf link? If yes, how? For me, it seems to only take the first entry. The same would go for collision models and maybe inertia. Originally posted ...
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1 answer
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displaying COLLADA 1.4 models in rviz

Thanks Ryohei (and Rosen) for your suggestions - after re-compiling rviz/robot_model from trunk, I was able to see the Barrett hand COLLADA model in rviz. Then I had our summer intern work furiously ...
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4 answers
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Converting SolidWorks stuff to URDF. STL and Meshlab problems

We have hard time converting our very cool robot SolidWorks files into URDF. They are way too complicated to make it somehow manually from scratch. As much I know there is no way to draw 3D model with ...
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2 answers
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what might cause the shoulder_lift_joint not to go all the way up?

Hi, I'm using JointTrajectoryAction to control the arm to follow a trajectory that can be executed well by openrave's controller. Most of the time, it works. But I found one case where the trajectory ...
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1 answer
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ROS Answers SE migration: URDF in Python

Has anyone written a class that does URDF parsing/output in Python yet? I'm debating putting one together, but don't want to replicate work. Originally posted by David Lu on ROS Answers with karma: ...
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2 answers
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How to import stl files into urdf files

I am trying to use stl files with the tag mesh with this code: ...
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1 answer
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Is it possible to replace colladadom dependence with macports?

robot_model contains a colladadom build, but it doesn't work in OS X (apparently because it's 32-bit instead of 64). However there's also collada-dom in macports. Is it possible to use the macports ...
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Why does robot_model fail in rosinstall

I get the following when rosinstall hits the robot_model line in .rosinstall: ...