Questions tagged [dh-parameters]

Denavit–Hartenberg parameters are the parameters associated with a particular convention for attaching reference frames to the links of spatial kinematic chains, or robot manipulators.

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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 ...
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31 views

Roy Featherstone toolbox robot model

I want to model these D-H parameters in spatial toolbox: Link: alpha, a, theta, d Link 1 : -90 0 theta1* d1 Link 2 : 0 a2 ...
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Resolved Motion Rate Control, Rotational Part

I'm controlling 6 DOF robot arm based on image processing. Robot arm will grab the object. Below what my system looks I can control the translational part of robot very well. But i cant control the ...
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89 views

Matlab Code for Lynx Robot

In this section, you will need to write a function lynx_fk which returns the positions of 10 points along the robot arm as defined later, given the joint angles of the robot. For this question, ...
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62 views

Rotation Matrices Using DH Parameters

I need to find rotation matrices between the frames of references of the vertices of the cube, and the DH parameters. For the rotation between the first to second frame of reference, I got alpha as pi/...
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59 views

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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128 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 to determine the direction of X-Axis in Denavit Hartenberg process? [Sketch inside]

The rules of assigning axes for DH parameters are (as I know them): 1- Z: in the direction of the axis of rotation/translation of revolute/prismatic joints. 2- X: perpendicular to the previous Z axis ...
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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-...
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DH parameters for lynx robot

Can anyone help me out with DH parameters and axis placement for below kinematic chain?
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D-H parameters verification

This robot has 2 revolute joints in advance then one cylindrical joint, then one revolute joint, then another cylindrical joint, then three revolute joints at the end. There is no D-H table for that ...
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326 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 : ...
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106 views

DH parameters for offseted elbow joint

Below is the axis setup for the elbow joint manipulator. I am trying to workout the DH parameters for the manipulator. Green frame represents the base and frame1. Starting from there, I am able to get ...
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696 views

Coordinate system of SCARA Manipulator

I am trying to understand how to draw coordinate system for forward kinematics. Figure is Could someone please explain how is the coordinate system drawn as per DH parameter? Basically when do we ...
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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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Robot Calibration using DH parameters

I'm new in robotics. My problem is the next one: I have a 6DOF robot manipulator and because the implementation was for real-time application my calculation time had to be really fast so that I used ...
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241 views

Between which joints does a given DH table row represent?

Say for example __ _____ | | ____ --------|_____|----------| |---------|____ |__| ...
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228 views

DH Parameters with offset base

I'm looking at a pan tilt (RR) system. I want to define the kinematics between a world frame and the end effector. Every example I've seen looks at the world frame as being at the first joint (the ...
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327 views

Validation of dh parameters

I am working on a concept of robotic arm for which I have fixed DH frames and parameters. Is there any way to validate the correctness of DH parameters and frames ?
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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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350 views

DH- Parameters of BCN3D Arm

Consider the following Arm: https://www.bcn3dtechnologies.com/en/bcn3d-moveo-the-future-of-learning/ I looked for the DH-Parameters of this arm and I found this: ...
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DH parameters solution for forward kinematics

I am stuck at a problem of solving DH parameters for a simple test mechanism. I know that the given mechanism is a structure but just for pure academic purposes assume that it's a real system. I only ...
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334 views

DH parameters to solve forward kinematics problem

When solving the kinematics problem for a robot using DH parameters, if there are some passive joints between the actuator and the end effector, do I have to define the axis and transformations of ...
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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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396 views

DH parameters of a PUMA-type manipulator

I'm struggling to find the DH parameters for this PUMA-type manipulator that yield the same results as the author (1): The way I'm checking if the parameters I have are correct is by comparing the ...
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177 views

For the second Paden-Kahan Sub-problem, how is 'r' determined?

When using Paden-Kahan Sub-problems to solve the inverse kinematics of manipulators, 'r' is described as the intersection point between the first and second twist axes. But how is this r actually ...
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How do the joint angles of a 4-legged impact the body's position with respect to the world frame?

For a four-legged robot (like Big Dog or the one shown here) how are the joint angles and "feet" position related to the body's frame in the world/inertial frame? For example, if I know the body's ...
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840 views

Modified DH Parameters for Puma 560 - Wrong Results

In continuation of my question on modified parameter for Puma 560 posted here Modified DH Parameters for Puma 560. Further I used a available dimension for Puma 560 here (FYI: the figure shows ...
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4k views

Modified DH Parameter for Puma 560

I'm trying to apply modified DH parameters (from Craig's version) to Puma 560. As per modified DH says, And the robot Puma 560 with axes and frame are, As per above sign convention, the sign of d2 ...
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258 views

Denavit-Hartenberg Humanoid robot

In humanoid robot, Which way we determine DH Parameter: DH parameter for each leg separability. Or, DH-Parameter for two leg together. and if I can calculate from any way, what about trunk how can ...
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908 views

Which is best way to calculate inverse kinematics for scara robot?

I am working on scara robot project and I have one big confusion. I am using simple trigonometric way(tan inverse traingl formula) to calculate inverse kinematics . But lot of people suggested me to ...
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410 views

Confusion between wrist, tool and end effector

I have a confusion between the wrist frame, the tool frame and the end effector as used in the unmodified DH conventions. Can you differentiate with diagrams?
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722 views

DH parameters for PRP manipulator

Can anyone share their DH parameters for a simple PRP manipulator. I have some confusion in setting up the axes and obtaining a solution.
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Assigning parameters in perpendicular axes: D-H is a must

So I was given a course assignment to assign frames and write D-H parameters for this robot using only 5+1 frames (with Frame $\{5\}$ at $P$ and Frame $\{0\}$ at $O$). And I assigned them like this: ...
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153 views

Do DH parameters change for a scaled robot 3d model?

I have the actual DH parameters of a robot: d1 = 0.4865 m d2 = 0.600 m d3 = 0.065 m a1 = 0.150 m a2 = 0.475 m all other di's and ai's are zero. Can I use these ...
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688 views

Find orientation through Transformation matrix

I have a robot with 3 rotational joints that I am trying to simulate in a program I am creating. So I have 4 frames, one base frame, and each joint has a frame. I have 3 transformation functions to go ...
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328 views

Modified DH Parameters?

Is the notation of the geometry of robots from Khalil and Kleinfinger be considered as one of the probably "many" Modified DH Parameters?
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DH parameters and Kinematic Decoupling

Is it possible to decouple a 5DOF manipulator? This question I asked earlier and I believe I got the right answers but I never show the drawings of the manipulator and now I'm hesitating during setup ...
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Getting pitch, yaw and roll from Rotation Matrix in DH Parameter

I've calculated a DH Parameter matrix, and I know the top 3x3 matrix is the Rotation matrix. The DH Parameter matrix I'm using is as below, from https://en.wikipedia.org/wiki/Denavit%E2%80 Above is ...
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821 views

Denavit Hartenberg parameters

Can anybody help figure out HD parameters for the case where two links with a revolute joint are in the same plane, thus that the variable angle is 0, but the twist is not 0. This is a simple drawing. ...
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714 views

Solving for DH Parameters

Given three sets of joint angles in which the end effector is in the same position, is it possible to find the DH parameters? If the robot has 2 DOF in shoulder, 2 DOF in elbow, and 1 dof in wrist, ...
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How to convert between classic and modified DH parameters?

I currently have a description of my 22 joint robot in "classic" DH parameters. However, I would like the "modified" parameters. Is this conversion as simple as shifting the $a$ and $alpha$ columns ...
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How to determine x-axis if the two z-axis are intersecting in Denavit Hartenberg representation

Suppose I have a 3 link(1 dimensional) chain in which all the joints are revolutes, the axis of first revolute joint is along Z-axis(global) and axis of second joint is along X-axis(global). The first ...
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Why do we generally prefer DH parameters over other kinematic representations of robot arms?

I am specifically interested in DH parameters versus other representations in terms of kinematic calibration. The best (clearest) source of information I could find on kinematic calibration is in the ...
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552 views

DH-Parameters for Forward Kinematics for Translatory Motion only

I am fairly new to the DH-transformation and I have difficulties to understand how it works. Why are not all coordinates (X+Y+Z) incorporated into the parameters? It seems to me that at least one ...
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Homogenous Transformation Matrix for DH parameters

I'm studying Introduction to robotic and found there is different equations to determine the position and orientation for the end effector of a robot using DH parameters transformation matrix, they ...
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629 views

DH Forward Kinematics for a Cartesian Robot (CNC Mill)

I am implementing a Denavit-Hartenberg forward transform for a 3-axes CNC mill. I know that the kinematic for such a machine is trivial and doesn't need DH, but I need to make appliable for other ...