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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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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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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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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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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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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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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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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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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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})\\ \...
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Assigning Frames and Deriving Link Parameters

The textbook I'm using doesn't have the answers to the practice questions, so I'm not sure how I'm doing. Are the following DH parameters correct given the frames I assigned? The original question is ...
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How to invert D-H parameters

I currently have a working kinematic chain made by a set of ten links in D-H convention (with usual parameters [ $A_i, D_i, \alpha_i, \theta_i$]). But my task currently requires the inversion of some ...
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Is there a tool for building and analysing robots (kinematics, control) visually?

I am reading research papers about robotics and many of them follow the same pattern: some construction is established kinematical formulas are read from the mechanical structure the state space is ...
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Inverse kinematics with joint contraints

I have a manipulator having 4 revolute joints with some movement limitations. So, when I apply inverse kinematics, I'm getting results which are out of limits. Please provide me an algorithm that ...
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Decision trees for solving 2D inverse kinematics?

While experimenting with the OpenCV Machine Learning Library, I tried to make an example to learn the inverse kinematics of a 2D, 2 link arm using decision trees. The forward kinematics code looks ...
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Computing the Jacobian matrix for Inverse Kinematics

When computing the Jacobian matrix for solving an Inverse Kinematic analytically, I read from many places that I could use this formula to create each of the columns of a joint in the Jacobian matrix: ...
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Inverse Kinematics in Java

I'm planning to write an Inverse Kinematics controlled 6 dof virtual robot for Android. I did some research on packages avaliable and couldn't choose the right one which will satisfy my needs on this ...
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Processor and command interface preference for a robot arm

I want to build a robot arm that'll be approximately 1.25 meter long and will be able to lift up to 2 kilograms. It'll have 6 dof and it is an expensive project. And most importantly, i am the only ...
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Are inverse kinematics and reinforcement learning competitive techniques?

Are inverse kinematics and reinforcement learning techniques contending techniques to solve the same problem viz. movement of robotic manipulators or arm? By a glance through the wikipedia article, ...
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With a 6-axis robot, given end-effector position and range of orientations, how to find optimal joint values

Given a six-axis articulated robot arm holding a tool at its end-effector, if I have a desired tool position and tool orientation, there will be exactly 1 solution to the inverse kinematics equation ...
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How can the inverse kinematics problem be solved?

The forward kinematics of a robot arm can be solved easily. We can represent each joint using Denavit–Hartenberg transformation matrices. For example, if the $i^{th}$ joint is a linear actuator, it ...

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