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Questions tagged [inverse-kinematics]

Inverse kinematics refers to a set of algorithms used to compute joint parameters necessary to move a robotic arm to a particular position, or more generally to apply geometric constraints on a mechanism (e.g. moving the center of mass of a humanoid robot).

Inverse kinematics is a subtopic kinematics and is a common encountered in robotics. In the simple case of a robot arm, there sections of the arm are connected by joints and there is an end-effector. A kinematic chain is a mathematical model of the rigid bodies and joint connectors in the robotic arm. Inverse kinematics equations are used to determine what joint parameters are required in the kinematic chain to move the end-effector to a particular position.

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How to aim gun using 2D IK with a fixed elbow rotation?

I'm doing an "aim-gun-towards mouse" with a 2D skeletal character with 2 bones, ArmUpper and ArmLower (hand is fixed) and I think I need some kind of IK solver. Here are the parameters: ArmUpper: Fixed position in the shoulder, but can rotate…
Niclas
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How to restrict joint rotations in CCD

I struggle desperately with maths, to try and improve I've been trying to create an IK solution in Unity. I have made a simple CCD algorithm which behaves as intended: https://www.youtube.com/watch?v=tZvdZGUxbbc But when I try adding constraints to…
Wannabe UnityDev
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Why is my avatar editor erroring out when trying to preview muscle settings?

Screen capture of the event happening: https://gfycat.com/ApprehensiveInconsequentialAmethystgemclam I am attempting to familiarize myself with the Unity Inverse Kinematics (IK) system, and so opened the avatar associated with the Ethan character in…
JustLoren
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Modelling a robotic arm motion in 3D, ideas?

I hope you don't mind if I ask for a bit of advice regarding modelling robotic systems. I've recently become rather interested in using inverse kinematics (IK) to control a 5 dof robotic manipulator. I have a solid foundation in IK but what I'm…
user657222
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How to use rotation with inverse kinematics?

I'm new to Unity, I'm doing a project using inverse kinematics, on one hand (with fingers), and I'm receiving hardware rotation data (quaternion), how to move the fingers of my hand if my only input is rotation , a quaternion on the last finger, and…
Donaldo Manzano
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Are there any Open Source AS3 inverse kinematics libraries?

I am looking for leads on an Open Source IK library for AS3. My project involves simple 2D limbs with shoulder/elbow/wrist joints. If I am unable to find anything I am going to try and write one, although my math is not anywhere near up to the…
jkopel
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How does SceneKit constraints work with bones?

I have a rigged character. I can retreive the bones nodes, and if I manually apply a rotation to those bones, I see the character switching to its new pose. Now, if I try to set a constraint to this same bone, it just doesn't move at all. I have…
AirXygène
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How to determine rotation of 2 arm segments based on target point?

I have a 2-segments robotic arm that needs to reach a specific point by setting up its joints (angles). Here is a drawing of the setup: My arm is positioned in the middle of the sketch so my origin is (width/2,0). These are the values that I…
user3458260
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7 DOF Inverse Kinematic with Jacobian and Pseudo inverse

I'm stuck trying to animate a character's arm with pseudo-inverse that has 7 DOFs. The overall FK is like this: (x,y,x) = TrootTshoulderRz(θ3)Ry(θ2)Rx(θ1)TelbowRy(θ5)Rx(θ4)TwristRy(θ7)Rz(θ6) Pendeffector. I'm not sure what I'm doing wrong.…
Esmail
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How to generate random matlab vector with these constraints

I'm having trouble creating a random vector V in Matlab subject to the following set of constraints: (given parameters N,D, L, and theta) The vector V must be N units long The elements must have an average of theta No 2 successive elements may…
CodeFusionMobile
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Vector rotation problem

I'm working on a program with IK and have run into what I had at first thought was a trivial problem but have since had trouble solving it. Background: Everything is in 3d space. I'm using 3d Vectors and Quaternions to represent transforms. I have…
user964426
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find the inverse kinematics for a 6dof articulated robot

I am working on a project to control a 6-axis robot and have successfully implemented the inverse kinematics for the first three joints. However, I am now stuck on how to solve for the inverse kinematics of the last three joints. I have the rotation…
Nico Waser
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"ValueError: `x0` is infeasible." for least_squares.py

I'm trying to use this code in Webots for one of the universal robots. The code works well until I try to the "ikResults" in line 49. The program is trying to use the least_squares.py but I'm getting the error for "'x0' is infeasible". This is the…
Kirito25
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Unity Animation Rigging Local and World Position Problem

I have a problem with changing TwoBone IK target positions. If i move a parent of the constraint targets while previewing as an animation, the moving will work. During runtime manually moving targets is the only working way. If i move a parent,…
506
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Rotate and translate a vector towards a target

I'm trying to learn and understand Inverse Kinematics by making it in PyGame. I've made a Bone class that has members a which is a PyGame Vector2 an angle and length. Finally it has a property b which is the calculated based on the previous 3…
user16541277
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