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# Questions tagged [forward-kinematics]

Forward kinematics refers to the use of the kinematic equations of a robot to compute the position of the end-effector from specified values for the joint parameters

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### What is a simple way to assign frames to a robot manipulator using D-H convenction?

I am studying the forward kinematics for robot manipulators, and I am focusing on the Denavit Hartenberg convenction for assigning frames to the various joints of the manipulator. The problem is that ...
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### Finding orientation angles of end-effector from the DH parameter table and transformation matrices

Let's say we have a manipulator with the following DH parameter table: and transformation matrices: A_{01}= \begin{bmatrix} \cos(q_1) & \sin(q_1) & 0 & 95\cos(q_1)\\ \sin(q_1) & -\...
12 views

### Forward kinematics of spherical parallel manipulators with revolute joints

I found an article that can help in my investigations. Forward kinematics of spherical parallel manipulators with revolute joints The problem is solved for the following system of vectors, which is ...
47 views

### Using gyroscope to calculate forward kinematics

I want to measure the end-effector position of the robot that I attached. I'm using both gy-25 and gy-521 for calculation of the angle. As shown in the picture, joint 1 has 2 DOF, one for spatial ...
8 views

### FlexiTimer giving errors in servo motion

I am working on a quadruped bot, spiderbot and I am trying to make a creep gait using Forward kinematics however, for some reason my code stops working after the execution of the line - ...
50 views

### Converting from Modified to Standard Denavit Hartenberg

This is probably a noob question. But as of right now I am having difficulty converting from the Modified DH to a Standard DH parameters for the Franka Emika Panda. I need standard because it allows ...
18 views

### 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 ...
16 views

### KUKA KR6 R900 sixx (Agilus) robot - Space frame screw axis

how do I find the space (and body) frame screx axis (s1..s6) of this agilus robot?
42 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 ...
102 views

### Null space of the Jacobian matrix for a robotic arm

I have doubts on how to find all the joint velocities that don't produce any linear velocity, so are in the Null space, when we are in a singular configuration. For example, suppose we have a 2R ...
41 views

### Why my kinematic diagram is not giving the same position and orientation while forward kinematics test?

I am sharing my matlab code so that you can also generate the simulation . ...
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### Is there any fault in my kinematic diagram?

I was doing forward kinematic test on a 6 D.O.F anthropomorphic robotic manipulator. So I modeled my kinematic diagram by D-H notation. But I am confused. Because I have simplified some terms here. I ...
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### DH Parameter for OpenManipulator X from Robotis

I try to solve forward kinematics problem for OpenManipulator X from Robotis by using standard DH convention. The figure and dimension of the robot like this pic I try to find DH parameter and got ...
43 views

### Forward Kinematics of non-planar robot using Roy Featherstone's Spatial Toolbox

I have a non-floatbase 3 DOF non-planar robot whose forward kinematics I need to compute using Spatial Toolbox. The code for this purpose is p = fbkin(q) but as my ...
32 views

### Can Swedish wheels be used in two wheeler configuration?

Can we use any of the Swedish 90°/45° Omni or Mecanum wheels in two wheeler configurations?
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### Calculate Roll Pitch Yaw from Modified Denavit Hartenberg

I'm using modified denavit hartenberg to represent my robot end-effector. But i couldnt find equation to calculate rpy if im using mdh. Below my MDH. I try use rpy equation for dh paramater(from ...
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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 ...
248 views

### DH parameters for a PPP arm

I found this picture on the web and was working through it to make sure I understood the derivation for a PPP arm. I believe for link 2, alpha_2 ought to be -90 and not +90. Additionally, I don't ...
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### How can Denavit-Hartenberg representation with only 4 variables describe rototranslations with 6 DOF?

I am wondering how the Denavit-Hartenberg representation is able to describe rototranslations with 6 DOF with only 4 parameters? Some context: Denavit-Hartenberg representations can be used to ...
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### Calculating the cartesian position of each joint with DH transform

Premise: I am by no means an expert on Robotics, I have to deal with this project where we use a robotic arm (franka emika), so feel free to assume that I got the basics wrong! I have this arm ( ...
51 views

### 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 ...
111 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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### Can a neural network emulate a physics engine?

Before a motion controller for a robot can be created, a step before is needed, called “system identification”. The aim is to create a prediction model which can say, what will happen if a certain ...
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### 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 ...
131 views

### Forward Kinematics with matrices

From the image, I would like to find out how joint 1, 2 and 3 can be computed by using forward kinematics? (Assuming a theta value was given) I understand that to get point 3 to origin (...
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### Wrong forward-kinematic after calculating from DH-parameters

I'm working on an exercise about DH-parameters for my robotics course in university and I ran into a problem, because my solution is different from the one given by my professor. I calculated the DH-...
213 views

### Forward Kinematics Frame Simulation in MATLAB

I've worked out the T matrix of the tip (position and orientation) with respect to the base frame of a 6 DoF robot for 2 seconds at 1kHz. So the size of the total T matrix is 4*4*1000. How can I ...
516 views

### DH parameters for lynx robot

Can anyone help me out with DH parameters and axis placement for below kinematic chain?
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### Forward kinematics: Findling the positions of points on lynx robot

I have a task to find position of 5 points on lynx robot. I need to write below function. This function takes theta values as input. function [ pos ] = lynx_fk( theta1, theta2, theta3, theta4, ...
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### Using pre multiply or post multipy for rotational matrix to get a new homogenous transformation matrix?

I am confused about how do I multiply the rotational matrix in this case. I know that both T1 and T2 needs to be multiplied by a rotational matrix but I don't know how to multiply the rotational ...
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### Getting position from joint angles in Matlab RigidBodyTree

I want to use matlab for estimating the position of end effector given joint angles. I saw convenient tool to build robot model using RigidBodyTree. My manipulator is planar, with only revolute joints ...
468 views

### Transformation matrix using DH parameters

I want to write a Matlab function which takes the DH parameters as input and outputs a 4X4 transformation matrix. The code I have written is : ...
367 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 ...
507 views

### Forward kinematics on Stanford manipulator

I recently had an exam in robotics and one of the questions was about forward kinematics on the Stanford manipulator below. The DH parameters were given and we were asked to calculate the angular ...
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### Significance of link length ratio in serial manipulator

I am formulating a problem to optimize link lengths of 3R serial manipulator shown below : I do not assume any explicit relationship between the link lengths, but in one of the papers (http://www....
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### Using jacobian of arm robot to calculate transformation matrices?

I have been given a Jacobian for a 3 revolute joint robot. I need to obtain the origins of each of the joint. Origins of the joints can be obtained once I get $T^0_1$, $T^0_2$, $T^0_3$ and $T^0_4$. ...
629 views

### How to check reachability of manipulator to a point?

I have written a MATLAB code for inverse kinematics of 3R robotic arm, which returns value of joint angles for given link lengths and end effector position and orientation. But if location of point is ...
328 views

### Optimization of link lengths for 3R serial manipulator

I am trying to formulate an optimization problem for determining link lengths of 3R manipulator shown in picture below, Following are the constraints, Robot arm should be reachable at point x = 100, ...
465 views

### Confusion in fixing DH frames

I am analyzing a concept of a surgical robot with 4 revolute joints and one sliding joint. I am not able to fix the coordinate frame for last prismatic joint. Following are the schematics of robot and ...
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### Inferring joint orientation on multi-joint arm

Not a robotics question in the strictest sense, I guess, but related closely enough, I hope: I have an arm-like articulated two(-plus-one)-joint appliance that I want to use as a 3D input device. It ...
156 views

### Converting product of exponentials from base frame to end-effector frame

This is a homework question from edx course Robot Mechanics and Control, Part II Given the following and expressing its forward kinematics as $T = e^{[S_1]\theta_1} ... e^{[S_6]\theta_6}M$ It is ...
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### How do CAD programs solve for Inverse/Forward Kinematics problem in Assembly?

I am trying to solve for the Forward kinematics of a spatial parallel manipulator. Its loop closure (LC) equations are pretty long, and are being solved using numerical methods. As I am adding more ...
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### forward and inverse kinematics of arm

I'm trying to figure out to a problem with a planar manipulator. The manipulator has a base effector and L1 and L2 with 3 joints. Question: INVERSE KINEMATICS Given the ...
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### How to update the cartesian target when the robotic arm has a communication delay?

My robot system uses a 3D mouse to teleoperate the robotic arm's TCP. The robot returns its TCP's position every 10-20 milliseconds to the remote PC. The remote PC returns the new destination based on ...
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### DH Parameters of RRP planar manipulator

I have been learning forward kinematics and having some trouble with coordinate systems and dh parameters with prismatic joints. Trying to work through this question. Trying to work this out I ended ...
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### Get the arm joint angles with kinect 1

I am Carlos Barreiro and I am studying a Robotics Master. Now I am working with my Thesis. The project consists in the teleoperation of the a robot with Kinect (model 1). More specifically, I am ...
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### Forward kinematics equations

I'm stuck at computing forward kinematics equations. I have configuration of the first two joints like on the following image: Transformation from the origin to the first joint basis is trivial: ...
285 views

### How to relate forward kinematics into PWM/speed?

I am having a hard time understanding how to relate forward kinematics to things one can control in a robot like PWM and reading encoder values. For example, how to relate the encoder values from ...