Questions tagged [inverse-kinematics]

Inverse kinematics is a subtopic of kinematics dealing with equations that describe the joint parameters necessary to move a robotic arm to a particular position. Also called motion planning.

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Seeking Advice on a Generic Analytical Method for Inverse Kinematics of Various Robot Manipulators

I’m working on developing a generic analytical method to solve the inverse kinematics (IK) for different types of robotic manipulators. My goal is to create a solution that can handle various robot ...
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1 vote
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Robotic Dog Kinematics & RVIZ

I am working on a summer project involving creating quadruped robot. I am in the process of creating a simple walking gait, to which I have fundamental understanding of the inverse kinematics. I am ...
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MoveIt Inverse Kinematics

I am using MoveIt to control an ABB GoFa, there is a way to get all the inverse kinematics solution given a target pose in cartesian space? I'am using the service GetPositionIK() but it returns just ...
1 vote
56 views

Inverse Kinematics for a 2DOF planar robot

I have a simple 2DOF planar robot with this configuration: L1 and L2 are the lengths of my 2 arms. L1 is 245.5mm and L2 is 160mm. Alpha is the first angle (the one of the base) and beta is the second ...
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Question about inverse kinematics for 2 axis gimbal

If I have a 2 axis gimbal (pitch and yaw) and I want to set the camera to a specific inertial orientation (in the world frame), how can I do this? How do I know what to set each motor to achieve this? ...
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Very high position_tolerance with inverse kinematics

I finally managed to make my manipulator work also with Pose Goal using KDL as Inverse Kinematics plugin. The problem is that I cannot in any way go below a certain level of position tolerance (0.12) ...
54 views

Deviation from real vs nominal DH parameters

some time ago, i built an inverse kinematics solver for industrial 6R robot arm. It work fine and i was able to use different robot brands, usually i took the DH parameters from robot's drawing and ...
25 views

Dexterous Workspace

Can anyone please help me understand how I can get the dexterous workspace I know how to obtain the reachable workspace but in 3D I can't see the dexterous, anyone know of any tricks or tips? Would ...
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Arduino Scara Robot inverse kinematics

I am building a simple scara robot using an Arduino Uno with a CNC shield and for that, I programmed a simple library (Here a normal program for testing purposes). I keep getting back NaN so not a ...
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67 views

Inverse Kinematics, indicate if multiple soltuions exist using a matrix

I'm trying to practice inverse kinematics and I'm having a really tough time understanding how you can indicate if multiple solutions exist just using a matrix. I also don't know how I would indicate ...
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Is ROS capable of inverse kinematics for a 6 DOF robotic manipulator of general geometry?

If a 6 DOF robotic manipulator does not have a spherical wrist (the axis of rotation of joints 4, 5, and 6 coincide at the same point), the inverse kinematics are incredibly difficult. Is ROS (Robot ...
47 views

OpenRAVE IKFast scipy error

I'm attempting to use the python app pyikfast to generate an analytic solution to my 6 DOF arm. I was able to successfully run the pyikfast solver on the PUMA 560 arm so I know the solver can work. It ...
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IK numerical vs analytical solutions and singularities

Currently I'm using the Robotics-Toolbox python library by Peter Corke to perform inverse kinematics calculations for a 6 DOF (non-spherical wrist) robot arm. I'm using the robotics-toolbox ctraj ...
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Kinematics for tricycle drive robot

I have a tricycle drive robot with propulsion and steering in the front wheel, and the rear wheels are fixed. I want to calculate the robot's steering angle and front wheel velocity from the twist ...
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Biped Kinematics (HTM)

Some notations: IRF: inertia reference frame or world frame CoM: center of mass DoF: degree of freedom [x y z roll pitch yaw] I'm trying to implement the simplest kind of biped walking using 3D ...
54 views

How can I accurately calculate the robot configuration for a desired cartesian position, given manfuacturing discrepancies?

This is a question I have wrestled with for a while now and would appreciate any advice. I am writing an application which allows programming of different 6DOF industrial robotic arms. The output of ...
1 vote
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Inverse kinematics for an unusual system

I'd like to use inverse kinematics for an unusual system. Basically it looks like this: I have a bunch of small objects (let's say A,B,C,D... which can be modeled as points) connected with revolute ...
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Problem about create IKfast plugin for moveit in ROS noetic and Ubuntu 20.04

According the tutorial from MoveIt website There can't install openrave on ROS noetic, so I use the docker to pull this image from this website I can install this image successly, but I don't know how ...
1 vote
196 views

Getting preferred (elbow-up/down) IK solution in PyKDL

I am using PyKDL to compute IK solutions for the UR3e arm. However, as we know, multiple solutions are available for IK of the 6-DoF arm, and I need to identify the preferred one. Industrial arms have ...
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Three finger robotic arm history

I have a picture with robotic arm which comes from lego video (Lego Mindstorms Robotics Invention System 2.0 tour) and I was wondering when and where it was created. Very interesting stuff. It was ...
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What is the preferred approach to derive the kinematics/dynamics of a floating base 3-link robot?

I would like to derive the kinematics and dynamics of a floating planar robot with two leg links and a hip link while the robot is in free-fall (i.e. no ground contact at the "feet"). This ...
81 views

Relationship between Lie Algebra (Murray, Lynch) and spatial vector (Featherstone) approaches

I am curious about the relationship between the Lie algebra/group approach to robot kinematics given by Murray (et al.) in "An Introduction to Mathematical Robotic Manipulation" and Lynch (...
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Issues with cube stacking controller for Panda Robot using Behavior Trees and Task Space Control

I have been working on a controller for a Panda (Franka Emika) robot (simulation, RobotDART and py_trees) and i can't figure out why the gripping mechanism doesn't work correctly. Initially the robot ...
122 views

Motion planning for non-serial chain robotic arms

I am trying to do position motion planning with inverse kinematics for the MeArm model. I followed MoveIt tutorials and was able to achieve what I wanted with their provided robot example. However, I ...
126 views

How to calculate error for inverse kinematics?

I am implementing inverse kinematics on a robot, and I am confused about how to calculate error from my desired pose to my current estimated pose. Both are orocos-kdl frames that consist of a 3x3 ...
63 views

Finding shoulder joint orientation

Ok so I have been trying to find out shoulder joint angles from a kinect RGB-D camera.My end goal is to acquire these angles to feed them to a robotic arm (7DoF - 3 shoudler 1 elbow 3 wrist) and ...
150 views

Steer to a pose for a differential drive robot

I am working on a diff-drive robot that needs to go and dock into a docking station to charge when the battery is low. The charging socket is on the back of the robot, like a vacuum cleaner, so this ...
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Calculate joint torques in 3 joint RRR mechanism

I don't know if I could upload these things here, but I want solve the following exercise:. I undestand that I should use the following formula: But, I have to solve every joint torque, so how could ...
378 views

Redundancy, Null Space and joint limit avoidance

I am developing a controller for a Franka Emika with 7 DoF. The cartesian motion is working, but I'd like to add some constraints in the joint movement range, with the values described by the ...
480 views

How to control a 4 wheel mechanum wheel robot with PID?

I have a robot with 4 mechanum wheels. I implemented a pid controller on each wheel and as a result it doesn't drive straight. When I send a command to simply move in the x direction forward, it ends ...
744 views

3R Planar robot arm singularity

To find the situation where singularity occurs, the determinant of the Jacobian is used. For the RRR planar robot with angles $q_1$, $q_2$, and $q_3$ and the length $L_1$, $L_2$, and $L_3$ as shown ...
1 vote
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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 ...
23 views

Meaning of p(q) in the expression for minimum clearance from obstacle for redundant robotic manipulators

Can somebody who has studied Industrial manipulators or has worked on Industrial manipulators using Jacobian Inverse and Jacobian Pseudo inverse algorithm for Inverse Kinematics please explain what ...
94 views

Inverse Kinematics with SE(3) Target Derivation

Why are there square brackets around [V_b] when deriving it, but not when using it in the update?
392 views

Can MoveIT framework be used separately from ROS, i.e. "as a standalone library"?

As far as I understand, MoveIT can act as a IK/FK solver one can supply input into (i.e. end-effector xyz) and get an output (joint angle values). I'd like to utilize this aspect of MoveIT (version 1) ...
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1 vote
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KDL Inverse kinematic and initial guess

I am using KDL Inverse Kinematic Solver (LMA) for a kinematic chain of 8 DOF. The problem is that the convergence to solution depends on the initial values. I run the algorithm with many initial ...
1 vote
68 views

What could be the unit ( dimension) of the vectors spanning the Jacobian matrix?

Let the general forward rate kinematics equation for a serial mechanism be given as follows:  \begin{bmatrix} \boldsymbol{v} \\ \boldsymbol{\omega} \end{bmatrix} = \begin{bmatrix} \boldsymbol{J}...
188 views

definition of self motion

From my understanding, self motion refers to a set of joint velocities which doesn't cause any cartesian motion on the end-effector. Here, by motion it is meant both linear and angular components or ...
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angle rates wrt another frame

My manipulator has a gyroscope attached to its end-effector (ee). The sensor provides angular velocity in the form of angular rates. Those rates are wrt fixed axis, so they effectively represent roll-...
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1 vote