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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Is it possible to estimate a torque input to fit the robot arm to markers in world coordinates?

I'd like to control a humanoid in a physics engine to fit it to markers given as Cartesian worldspace coordinates. I'd like to realize this by estimating inputs to PD controller using some gradient-...
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Finding center of mass and support polygon for quadruped robot

I intend to find the center of mass of a quadruped robot and find the convex of the CoM inside the support polygon. I want to make a model of this, which is further going to help me develop stable ...
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OpenGL C++: Inverse kinematics using Jacobian Transpose doesnt work

I am using glm library and OpenGl for this. This is might not be directly related to Robotics but I guess Inverse kinematics is used there I have 3 joints Here is my code ...
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Robotic Manipulator 3-RRP v2

I recently asked a question about a 3-RRP manipulator but the only answer didn't work for my robot. I would describe the manipulator as an arm that rotates around the shoulder over the x-y axis, the ...
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3-RRP manipulator robot

I'm having some issues with a planar manipulator I have to deal with. The first two moves are rotational and the third one is a prismatic one. The shoulder and elbow move around the X-axis, while the ...
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How to find inverse kinematic equations for a quadruped robot to make it walk?

I have made a model of quadruped robot (sprawling/spider type and not dog type) in V-rep and now I want to make it walk by using creep gait. (i.e moving 1 leg at a time) As I understand, I have to ...
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Building trac_ik_python for Windows 10 using VisualStudio2019

I’m trying to build TracIK-python with Microsoft Visual Studio 2019 for Windows 10 and am making use of the available trac_ik_wrap.i file in the swig folder to ...
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38 views

Having trouble getting correct homogeneous transformation matrices for my robotic arm

I am working on a project to build and program a robotic arm. And, no, this is not a HW problem. I have watched a ton of tutorials on the HTM, but its still not fully clicking. The image shows my ...
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IK - 3dof - iterative

I want to solve for a 3dof planar arm using gradient descent to approximate end position. Now I am a little confused about the formula and was wondering if someone can help me out. This is my thought ...
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Inverse kinematics of a sun tracker with swapped axes

I am realizing a sun tracker based on latitude, longitude, and date-time. The system calculates the azimuth and elevation angles to track the sun. In a classic sun tracker, the azimuth axis is ...
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44 views

Jumping motion in point to point movement

I have one question about point to point movement. Let's say the end-effector is placed at $(0,0,0)$ and the goal position is at $(10,0,10)$. The corresponding joint angle value changes $d\theta$ can ...
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Do I need to use Inverse Kinematics if I have the coordinates of all joints?

So I have the positions of all the joints (x,y,z) of a robot arm. I need to calculate the angles of the joints to feed them to another similar robot arm. I cannot get the angles from the robot I need ...
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Looking for solution to 6R inverse kinematics

I graduated from college a few years ago and over that past year have been trying to self-study robot kinematics. My long term goal is to purchase a used industrial robot and retrofit it with a real-...
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Help understanding decoupled inverse kinematics

I've been researching decoupled inverse kinematics with respect to industrial robots. The assumptions made in the decoupled equations greatly simply the equations, however I am having a hard time ...
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Tips/Tricks for Initial Guess of the Joint Variables in Inverse Kinematics

It seems like there should be a set of best practices or something to reduce the iterations of the Newton-Raphson method to the inverse kinematics. Does anyone have any tips or tricks for choosing an ...
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Inverse Kinematics of Puma 566 giving low angle results with DH convention

I am new at the robotics area, and i need to deliver an activity until this week in my college based to solve the inverse kinematics problem from an article that doesn't have any code done, and after, ...
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Number of inverse kinematics closed form solutions for ABB IRB 140

I've read that 6 dof manipulators give eight closed form solutions, according to a paper. What is the number of iK solutions for the ABB IRB 140? (last three axes intersect but there is a offset ...
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Home position of robot created using modified DH Parameters doesn't match the real robot

I have created a 6-DOF robot using RigidBodyTree() method and modified D-H parameters using robotics toolbox in MATLAB. The modified DH parameters for the robot are as follows: I have followed the ...
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Parallel Inverse Kinematics for Multithreaded Architecture (or GPU)

Here, you can find a nice academic paper about this topic. What I am looking for it is a real implementation of it or, instead, any other implementation of IK algorithm that can run in a many-core or ...
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55 views

Explanations about inverse kinematic

I am currently designing a 2D simulation of a 3DOFs robotic arm in order to develop a better understanding of inverse kinematic (so as to avoid breaking more components than necessary) but despite my ...
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Kinematics with Product-of-Exponentials terminology: not forward, not inverse

I'm working on a kinematic estimation algorithm, and am trying to come up with the right terminology. I'm using the Product-of-Exponentials formulation for kinematic chains (and ignoring position ...
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2answers
107 views

Inverse Kinematics “Can not converge” issue

I'm a complete beginner with LabView and I have been practicing forward kinematics with the help of a tutorial I found. It's been a learning curve but I've managed to understand a few things. However,...
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3D Inverse Kinematics Jacobian Construction

I am following this article: Overview of Jacobian IK From the link, an example says: O is a pose vector which represents the initial orientation of every joint And following this, it gives an ...
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3D Inverse Kinematics Jacobian

I am reading up on inverse kinematics and have a few questions I hope could be answered. This example is from a 3-revolute-joint, where $ E $ is the end effector and $ G $ is the goal position of the ...
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Question about programming approach of a dog like quadruped robot

I and my friends are planning to build a dog like quadruped robot. We have designed it like MIT Cheetah Mini like legs structure, each leg having 3 Servos, 3rd DOF for rotation. We have calculated ...
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Add control and planning trajectory to double pendulum [closed]

How do I control a double pendulum to get the end effector link to go in the trajectory shaped in a perfect circle? I have the equation of the circle to go in but I don't know how to get the double ...
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108 views

Is it correct to think of forward kinematics as merely a 'check' for the inverse kinematics?

When the only inputs to your robot are the next x,y,z coordinates of the next point on and on, I can simply just calculate IK to find the angles and make my actuators move to these angles. Whats the ...
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underactuated robot problem

Lets say the robot has 4Dof and the operator gives (x,y,z,roll,pitch,yaw ) as control input( rank(J) < dim(task) ). Now the robot is overwhelmed and will probably show some jerky movement. But can ...
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Path Planning for Spherical Wrist (RRR)

I have found the inverse kinematics of a spherical wrist. The wrist is not attached to any other type of arm, it is the sole controller. Based on this IK solution, how can I generate a path plan for ...
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731 views

Inverse Kinematics Problem of Articulated Manipulators Arm

I have a robotic arm consist of three joints (servomotor for each joint), as shown in the figure below: Notes: Each servomotor rotates around 180 degrees. The angles of the theta2 and theta3 ...
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Singularity problem at Inverse kinematic solver

I am struggling with this problem for days. I really hope that someone could give me a hint what the problem is. The robot consists of 5 axes. The first axis rotates around the z-axis and other 4 ...
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1answer
139 views

Arm path planning with obstacle avoidance in Unity

My application is not specifically in Robotics, but the problem that I'm trying to solve seems to have been studied primarily from the viewpoint of Robotics, so I am hoping to get an answer here. ...
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300 views

Inverse kinematics for differential robot knowing linear and angular velocities

I have a differential robot and I am using ROS to run it. When I need to move the robot, I can send commands to it, specifically linear X and angular Z velocities. Linear X is in m/s whereas angular Z ...
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379 views

How do I find the inverse kinematics of a 5-DOF manipulator having the following DH parameters?

alpha = [ -90, 0, 0, 90, 0] a = [ 0, 400, 200, 0, 0] d = [63.5, 0, 0, 90, 100] I am trying to calculate the joint angles but I am stuck ...
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76 views

Humanoid Robot Arm

I have a modeling design for Humanoid robot arm in simscape-SimMechanics in Matlab, I am trying to use the inverse kinematic to make a reaching movement for the arm to the target position; however, I ...
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help to find the bug for calculating inverse kinematic using jacobian

I am calculating inverse kinematic for 5dof robotic arm using Jacobian matrix (first time). i used following formulas to do my calculation and also implemented in my code. for more information please ...
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constraining rotation in jacobian IK algorithm

i'm implementing a damped least squares IK algorithm for an articulated arm, based on the work here. I have the algorithm working well, but it occasionally produces solutions that have segments ...
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253 views

Struggling to understand Jacobian Inverse Kinematics

I'm trying to find a method to control a moveo 5dof arm. My goal is to calculate the right angle to turn for each stepper motor to reach a desired point in real environment. I've spent time looking at ...
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how to normalize PWM if the value exceeds the maximum speed limit

I have implemented inverse kinematics for nonholonomic mobile wheeled robots, and the RPM range of the motor that I used is -50 to 50, while for PWM is from 1300 to 1700. But in certain cases, the RPM ...
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How to implement end effector orientation in generic IK solver

I am trying to script a basic, lightweight IK solver with a Jacobian Transpose method. I have gotten a basic script that reach the desired position very quickly. What I am not able to do is achieve a ...
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python code for closed form inverse kinematics solution

I solved the inverse kinematics of a 4DOF robotic arm (which is not planar) and I wrote this code bellow in python. The coordinates for each joint is: I considered the first three joints as a wrist ...
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264 views

Inverse kinematics with end effector orientation?

I'm trying to implement an inverse kinematics solver, but this time even with the end effector's orientation. I succeeded with the case when the end effector only requires the position. I learned ...
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113 views

Reachable Position with endeffector robotic arm

I have a 7 DOF robotic Arm. All the 7 Joints are rotational and have upper and lower joint angle limits. Now assume my end effector has a certain Pose $x = [X, Y, Z, a, b, c]$. My Question now is ...
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Create path with minimum curvature for Ackerman drive

I'm trying to create a trajectory between two given poses for an Ackerman drive. The poses are defined as follows: Current Pose position $(x_0, y_0)$ rotation on z-axis $\theta_0$ Final Pose ...
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2answers
295 views

Inverse Kinematics - How to only find a unique joint angle solution in 4 dof robot?

I have to develop an algorithm to determine the necessary joint angles to achieve a desired TCP position and orientation in a 4 joint manipulator. I have come across a concept called "degeneracies", ...
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179 views

Help in Computing Inverse Kinematics of a 5 DOF Robot Config

Its is a robot config with 5 DOF. We are provided 2 offsets d1 and d2. d1 and d2 are both 0.04 meter. It is confusing for me alittle bit. I am attending lectures online but I am having trouble ...
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5 DOF robot - Velocity Inverse Kinematics

I am modelling an articulated robot arm with 5 degrees-of-freedom from igus (igus Robolink). I deduced its direct kinematics equations using Denavit-Hartenberg parameters and homogeneous ...
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186 views

Finding Joint speeds for each joint of a 6DOF arm (UR10) using the Inverse Jacobian

Background: I have access to a UR-10, 6DOF robotic arm through my school (I'm very new to robotics). I know the desired set of linear speeds that I want in the x,y, z-direction in terms of the end ...
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ROS: Human to Robot Mapping (Baxter)

I'm having some difficulties understanding the concept of teleoperation in ROS so hoping someone can clear some things up. I am trying to control a Baxter robot (in simulation) using a HTC Vive ...
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333 views

Understanding MoveIt! and OMPL more deeply

I wanted to know the actual mathematics behind the path planners MoveIt! uses for manipulators from OMPL. I tried to look into source codes but couldn't get enough details. I wish to know: How cost ...