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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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Implementation of inverse kinematics solution in c++

I am having some issue with implementing a least square solution of the inverse kinematics problem. The q configuration I get are rather large, or makes no sense, so I was hoping someone here could ...
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Performing inverse kinematics based on a displacement of the end effector?

I think i have an simple problem, but can't my head around how i should resolve it... My setup looks like this: The grey box on end effector is supposed to be an camera, which measures a dx,dy,dz ...
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Implementing an analytic version of an inverse kinematic

People have recommended me implement an analytic version of inverse Jacobian solver, such that I won't be forced only the least square solution, but would have an local area of solution near to the ...
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inverse kinematics for 6 jointed robots

I am a uncertain about how to compute the right homogeneous transformation matrix to compute an inverse kinematic Q-configuration. Looking at robot like this Where at the end of this robot I have ...
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Extracting as many possible end configurations as possible

I am trying to implement a path planner to generate a path that moves the robot from q_start to q_goal. Q_goal is extracted from a stereo camera mounted on the tool, from which I extract x,y,z ...
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Most accurate rotation representation for small angles

Assume that I have a rigid body for which I know that it can rotate with respect to a global reference frame (which is considered fixed and already given) for only a few degrees of angle, so I can ...
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174 views

Hand-eye calibration?

I am having an issue with some hand-eye calibration. So i am using a simple robot which at its tool point has an stereo camera mounted on it. I want to perform some visual serving/tracking based ...
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What is the common process to place a robotic arm gripper

I implemented a simulation for a robotic arm that has to grab things. This arm has a 6DOF structure and a simple gripper on the top. I made a simple CCD IK algorithm to control the arm. I can use it ...
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354 views

Jacobian for Inverse Kinematics with quaternion of end effector

Quaternion has four parameters. Calculating Jacobian for inverse-kinematics, 3 positions and four quaternion parameters make Jacobian $7\times7$ instead of $6\times6$. How to reduce Jacobian to $6\...
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Inverse kinematics with singularity in MATLAB

I want to find the general coordinates q=[alpha,beta,gamma] (3 revolute joints) that minimizes the norm ||rGoal - r||_2 with rGoal not included in the manipulator workspace. The problem is already ...
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Evaluating the similarity of two 7 Degree of Freedom Arms

I am working on the Baxter robot where I have a first arm configuration and a bunch of other arm configurations, where I want to find the closest arm configuration to the first among the many other ...
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2answers
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Inverse kinematics after calibration

I am working on a 6DOF robot arm project and I have one big question. When I first derived the inverse kinematics (IK) algorithm after decoupling (spherical wrist), I could easily get the equations ...
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List of books similar to Thrun's Probabilistic Robotics for robot mechanics and manipulation [closed]

What? Put together here a list of books (like the one for C/C++ on StackOverflow) that are spiritually similar to Sebastian Thrun's Probabilistic Robotics for robotic manipulation and mechanics. Why?...
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Finding Center of Mass for Humanoid Robot

I've been working on Humanoid Robot, and I face the problem of finding the Center of Mass of the Robot which will help in balancing the biped. Although COM has a very simple definition, I'm unable to ...
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Inverse Kinematics of DLR/HIT II Hand

I am trying to find the inverse kinematics formulation of DLR/HIT II hand. Till now I had success in finding an analytical method described in the thesis of Mavrogiannis, Christoforos I. named Grasp ...
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2answers
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q-state vector used to define the transformation matrix? how?

How can it be used to determine the transformation matrix? an example could be at computing the inverse kinematics for small displacements: J(q)$\Delta$q = $\Delta$u $\Delta$U is a vector defining ...
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Phantom Omni type robot Inverse kinematics solution

Guys my robot looks like this, Thanks to @croco I came to know that it looks much similar to Phantom Omni. Since it looks similar to the phantom Omni I am trying to get the inverse kinematics ...
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BiRRT: Getting path from an array of 7 DOF angle configurations

I've kind of finished implementing a BiRRT for a 7 DOF arm, using a KD-tree from numpy.spatial in order to get nearest queries. A picture is below: I'm currently having trouble with the fact that it ...
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inverse kinematics osciliations..

I am the moment having some issues with an Jacobian going towards a singularity (i think)as some of its values becomes close to zero, and my robot oscillates, and therefore thought that some form of ...
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Robotic Manipulator [closed]

I have started working on robotic manipulators and got into a project which deals with control of robotic manipulator using artificial neural networks (solution of inverse kinematics and trajectory ...
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Visual servoing - tracking a point

I am trying resolve some issues i am having with some inverse kinematics. the robot arm i am using has a camera at the end of it, at which an object is being tracked. I can from the the camera frame ...
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1answer
344 views

Finding cubic polynomial equation for 3 joints

My professor gave us an assignment in which we have to find the cubic equation for a 3-DOF manipulator. The end effector is resting at A(1.5,1.5,1) and moves and stops at B(1,1,2) in 10 seconds. How ...
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871 views

Manipulator end-effector orientation with quaternions

I have the following problem: Given 3 points on a surface, I have to adjust a manipulator end-effector (i.e. pen) on a Baxter Robot, normal to that surface. From the three points I easily get the ...
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Forward kinematic and inverse kinematic… When to use what?

I am not quite sure if I quite understand the difference between these two concepts, and why there is a difference between these two concept. Yesterday I was trying to compute the jacobian needed ...
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Denavit Hartenberg parameters - 3DOF articulated manipulator

I am trying to solve a forward kynematics problem for a 3DOF manipulator. I am working with the Robotics Toolbox for MatLab created by Peter Corke and after calculte the DH parameters and introduce ...
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Running my 3 DOF Inverse Kinematics Code: Works in MATLAB, not in Python

I asked a question similar to this earlier, but I believe I have a new problem. I've been working on figuring out the inverse kinematics given an x,y,z coordinate. I've adopted the Jacobian method, ...
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3 DOF Inverse Kinematics Implementation: What's wrong with my code?

I am currently trying to implement an Inverse Kinematics solver for Baxter's arm using only 3 pitch DOF (that is why the yGoal value is redundant, that is the axis of revolution). I for the most part ...
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Robot arm reachability of a pose in Cartesian space

Given a set of robot joint angles (i.e. 7DoF) $\textbf{q} = [q_1, ... , q_n]$ one can calculate the resulting end-effector pose (denoted as $\textbf{x}_\text{EEF}$), using the foward kinematic map. ...
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1answer
729 views

Inverse kinematics solution for 6DOF serial arm

My 6 joint robot arm structure doesn't meet the requirements for a closed form solution (no 3 consecutive axes intersecting at a point or 3 parallel axes...). What would be best method to adopt to ...
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3answers
489 views

Which joints to discretize for IK

I am using ikfast in OpenRave for my inverse kinematics. This is an analytical solver, so if your robot's DOF matches the IK type's DOF, then you get all possible solutions. But if your robot has ...
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597 views

7DOF inverse kinematics spherical wrist

Is it possible to apply kinematic decoupling for a 7 DOF 7R manipulator with spherical wrist? If it is possible, can anyone suggest a reference on how to apply this approach with a redundant ...
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1answer
391 views

Human arm inverse kinematics

Hi I want to implement an human arm robot and a task such as moving a glass between two points using Robotic Toolbox for Matlab by Peter Coorke. I'm a student and I'm a newbie in this kind of things ...
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Assuming I have the angle with respect to two beacons, and know the distance between them, can I localize myself?

Let's assume I have the following situation, and need to find (x,y). Is it possible? There does not appear to be more than one solution to the system, but my trigonometry is a bit rusty. I feel ...
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Is the geometric inverse problem's solution “continuous” for a redundant robot?

Let's say my redundant robot is at an operationnal position $x$. Is the set of all possible joint configuration "continuous", which would mean that it is possible to explore all the possible ...
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Jacobian transpose: how to calculate orientation error

I'm confused about how to compute the error in orientation. All the documents I've read don't explain how to do it. The error in position is simply the difference between the points. Let's assume ...
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How to find the body jacobain, for each link in a robot manipulator?

The links twist could be obtained, and thus The spatial manipulator Jacobian could be done, but when it comes to the body Jacobian, it is becomes difficult. Moreover, the adjoint transformation ...
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Can a Jacobian be used to determine required joint angles for end effector velocity/position?

I'm in the early stages of working with a simple robot arm, and learning about the Jacobian and inverse kinematics. From my understanding, the Jacobian can be used to determine the linear and angular ...
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2D Robot Arm Inverse Kinematics with minimum joint loads

Suppose I have a robot arm with $n$ linkages of fixed length and equal density whose motion constrained within a 2D plane. I want the end effector to reach a particular pose $(x^*,y^*,\theta^*)$. ...
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Inverse Kinematics Constant End Effector Angle

I have a simple RRR manipulator where one motor controls the base rotation, and the other two allow movement in a plane extending forward from the base and upwards/downwards. Are there any standard ...
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Numerical-Example for Paden-Kahan subproblems?

I am writing a kinematics library in Go as part of my final year project. I am working with Product of Exponentials method and have successfully implemented the Forward Kinematics part of this. I need ...
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Inverse Kinematics of Parallel Manipulator (Delta Robot)

Let me start off by saying that I am currently going to university majoring in computer engineering. I love software/hardware and I especially love robotics and I want to apply my knowledge of ...
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“Smooth” inverse kinematics model for 2-wheeled differential drive robot

I have been reading about kinematic models for nonholonomic mobile robots such as differential wheeled robots. The texts I've found so far all give reasonably decent solutions for the forward ...
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Computing inverse kinematic with jacobian matrices for 6 dof manipulator

I'm trying to calculate the inverse kinematic for an 6 dof manipulator. Task: A target point $p_{target} = (x,y,z)^T$ and the orientation $o_{target} = (a, b, c)^T$ are given and I want to get the ...
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Is there an analytical solution for inverse kinematics of a 6 DOF serial chain?

Let's take a 6 DOF robotic structure. It's consisting of the 3 DOF global structure for the position - and the 3 DOF local structure for the orientation of the endeffector. If the last 3 axis (of the ...
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3answers
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Jacobian method for inverse kinematics

I have big problem. I have to solve inverse kinematics for a manipulator with 6-DOF using jacobian method. From what I know to do that I need to have matrix of transformation and Denavit–Hartenberg ...
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2answers
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Kinematics of a 4 wheeled differential drive robots

I have a 4 wheeled differential drive robot, like the Pioneer 3-AT. There are only two motors, one for left wheels and one for right wheels. I want to send velocity commands to the robot, I'm using ...
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Power Model for humanoids

I am in the process of creating a Power Prediction Model for the Hubo Robot. The Robot has 38 Degrees of Freedom and has a computer some sensors and motor boards. The motors are powered through Motor ...
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3answers
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Finding inverse kinematics algorithm for a specific manipulator

I need to find a way to solve invrese kinematics for Comau SMART-3 robot. Could you give me a few hints where to start looking? I have no idea about robotics and I couldn't find an algorithm for this ...
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Algebraic and geometric in inverse kinematic

I'm just wondering that is there any case that when algebraic way can't solve the problem while the geometric can ? Cause I'm working on a 2DOF robotics arm This one, I know the length of L1 and L2, ...
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Is there a way to determine which degrees of freedom are lost in a robot at a singularity position by looking at the jacobian?

For a 6DoF robot with all revolute joints the Jacobian is given by: $$ \mathbf{J} = \begin{bmatrix} \hat{z_0} \times (\vec{o_6}-\vec{o_0}) & \ldots & \hat{z_5} \times (\vec{o_6}-\vec{o_5})\\ \...