Questions tagged [manipulator]
manipulator is a device used to manipulate materials without direct contact.
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Developing world-frame Jacobian using product of exponentials [closed]
I am going through different texts (Spong Robot Modeling and Control, Murray Mathematical Introduction to Robotic Manipulations) and I am seeing different Jacobians developed for the same RRRP ...
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Different methods to determine DOF: Chebychev-Kutzbach-Grubler method vs. Screw method
I'm familiar with Chebychev-Kutzbach-Grubler method to determine degree of freedom of a robot arm. But it seems this method fails to calculate the mobility of some parallel robots, as explained here.
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How to calculate potential enegy of manipulator dynamics?
I'm trying to obtain dynamics of a 4 DOF robot. Firstly, I calculated all Transformation matrices and Jacobians. While solving Lagrangian there is two main things one is kinetic energy and the other ...
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Sinusoidal trajectory of each cartesian coordinate for the end effector
Consider a 7-DOF robotic manipulator. I want the end effector to follow a predefined trajectory and suppose I care only about the position and not about the orientation. So, the rotation part of the ...
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Dexterity calculation with dual quaternions
How can the manipulability of a robot arm be calculated when the kinematics are described with screw theory such as dual quaternions? These methods are sigularity-free, but what could we say about ...
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My Pick and Place Program Not Working
hope you are all well.
I am trying to finish a capstone project on Coursera. It asks me to carry a cube object from an initial position to goal. This video shows the movement.
Project website: http://...
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Robotic Platforms Similar to the PiBot(Locobot)
I am brain storming platforms to use for a project I am working on. I'm looking for an mobile platform with a manipulator attached. I originally was focusing on the PiBot, but after doing some ...
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Multi-Link Robot Degrees of Freedom
I want to compute the DOF of this system if it composed of (n) such links grasping this common object using Grubler's formula obtaining the solution as a function of (n), considering this to be a ...
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Is it possible to control a 5 DOF manipulator in the 6 DOF Task Space?
I am referring to pre-computed torque control techniques that are based on the Task Space dynamic model.
Maybe by using pseudo-inverse for the Jacobian and the task space inertia matrix ?
Cheers,
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How to calculate displacement of the end effector by the yaw, pitch, and roll in the spherical joint?
For planar robots, we can calculate how small changes in the angle of each joint corresponds to the displacement of the end effector, by constructing a jacobian consisting of cross products between ...
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Cartesian Velocity Control between Two 3D Poses
I am really struggling to understand how to do Cartesian velocity control when 3D rotations are involved. So, below is a very simple example which I am hoping somebody can help me with.
Let's say the ...
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How do I decide the minimum number of link lengths and joints my manipulator must have from the configuration space?
I have a configuration space in 3D where my manipulator must reach certain points. Taking into account all the factors how do I decide the mininum number of links and joints my arm must have?
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Inverse Kinematics with Orientations
Let's say I have a robot consisting of a base $B$ and a manipulator $M$. The pose of the manipulator can be expressed as the transformation matrix $T_{BM}$. I also have a goal $G$ which I want to move ...
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Controlling the pose of a manipulator using inverse kinematics
I want to control a robotic manipulator in Cartesian space, using inverse kinematics. I know that I can do this using $\omega=J^{-1}v$, where $\omega$ is a vector of joint velocities, $J$ is the ...
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Cartesian Impedance control Damping Design (Double Diagonalization)
In the literature, it is often seen that for a system:
\begin{align}
\Lambda \ddot{e} + D_d \dot{e} + K_d e = F_{ext}
\end{align}
A dynamic damping matrix is required for a robot to take ...
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How do I find the minimum time for computing a trajecotry for a robotic arm?
I am studying robotics and I am focusing on trajectory planning.
I have been struggling with this topic for a while, and I still have some doubts that I cannot solve. One of them is the following:
I ...
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What is the reasoning for solving inverse kinematics problems?
I am a student, and I am studying robotic arm manipulators. I am focusing on the concept of inverse kinematics, I have understood is the process of finding, from the direct kinematics, the joint ...
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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 ...
Ben♦
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Jacobian Derivative (Analytical?)
If I understand this correctly, given the Jacobian Derivative $\dot{J}(q)$ derived using the method presented from the paper by (Rhee, J. Y., & Lee, B., 2017)
where the algorithm summarized ...
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D(q) Inertia Matrix and the Jacobian Matrix
There is something I need to verify.
Say we have the following RPR robot manipulator.
The DH table
yields 3 rotational matrices:
\begin{equation}
R^0_1, R^0_2, R^0_3
\end{equation}
Using these ...
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Can workspace of a manipulator change after considering its dynamics?
As per my knowledge, the workspace of a manipulator can be determined if one knows the forward and inverse kinematics. But is it possible that the workspace of the manipulator can change after ...
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What is canonical grasp?
What is a canonical grasp and how is it different from normal/other grasp? I've searched through internet and forums but haven't found any answers.
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Understanding Impedance Control
I have a question regarding impedance control for a robotic manipulator.
Given that we have a task space trajectory:
$\ddot{x}$, $\dot{x}$ and $x$
And the dynamics model of the robot:
$$\tau = M(q)\...
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Visual-Positioning Method
I'm working on mobile manipulator and trying to do visual-positioning of the end-effector.
My camera will located around 1-2 meters from the robot.
I'm sure i cant use color tracking method because ...
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Find the kinematic parameters using DH by Craig convention
I am trying to find the kinametic parameters using the J. Craig of the DH parameters for the following 2-DOF robotic manipulator.
where $\ x,y $ are the axes of the reference frame and $\ q_1 , q_2 $...
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Why in trajectory planning in joint space the manipulator never crosses a singularity?
I am studying robotics kinematics and I have studied that if we plan a trajectory in joint space it is impossible for the robot manipulator to cross a singularity during its motion, while in cartesian ...
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What does "resolution of a sensor" mean? [closed]
I am studying robotics and I am focusing my attention on the sensors used on robot manipulators. I have seen that there a proprioceptive sensors, such as encoders, and exteroceptive sensors, such as ...
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Problem defining rotation matrix
I am studying robotic kinematics , and given the following manipulator with its D-H frames assigned:
I have to find the rotation matrix $R_{e}^{2}$, which is the rotation matrix of frame $e$ with ...
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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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How to use artificial potential function in manipulator path planning?
The artificial potential method always takes robot as a point, if the manipulator is 6 degrees of freedom, how to use this method in path planning while six links can avoid the collision.
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Model of two link rigid manipulator
I am working on parameter estimation of a rigid two-link manipulator as shown in the picture below.
Unlike the cylindrical links shown in the above image, my robot has links of oval shape.
So the ...
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What is the difference between multi-link flexible manipulators and continuum robots?
I read the review[1] on flexible manipulators, the modeling method of multi-link(even if single-link) flexible manipulators seems very different from the continuum robots like OctArm(multi-section), ...
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Kinematics and dynamics analysis of manipulator in zero gravity
Is there any change in the analysis of kinematic and dynamic analysis of the manipulator which is working in zero gravity or microgravity?
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Articulated configuration
I'm reading Theory of Applied Robotics, 2nd edition by Jazar. The author states that articulated configuration has the following form: $R \vdash R \perp R$ where $R$ stands for revolute joint, $\vdash$...
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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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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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Definition of robotics manipulator?
I'm new to robotics, I don't understand the way wikipedia defines robotics manipulator. If there is no any direct contact how could the robot move things within his work envelope.
In robotics a ...
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What is the degree of freedom of the following drone?
This might be a stupid question to ask here .i am confused whether the dof of this drone is 3 or 4?
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Calculating Error of Arm Manipulator
How can we calculate the error position of arm manipulator?
Let's say we have a Transformation Matrix:
$$\begin{bmatrix}
R_{00} & R_{01} & R_{02} & x\\
R_{10} & R_{11} & R_{12} &...
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Fuzzy logic controller for controlling a four-bar linkage
I am trying to design a control system to move a joint of four bar linkage according to desired trajectory. A dc-motor is used to move the joint.
Can fuzzy logic controller be used to solve this ...
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Effiecient computation of coriollis matrix
I want to perform kinodynamic motion planning on a 6DoF hybrid manipulator. I calculated mass matrix, coriollis matrix etc using the lagrangian method. The coriollis matirx was calculated symbolically ...
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Why do I need impedance control?
I am having a hard time understanding the impedance controller.
I see that it looks at the manipulator as impedance and the environment as admittance. However, it is hard to grasp the concept and ...
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Task Space Control Parameters for 6-Dof Manipulator
I'm developing a Task Space controller based on speed for a Universal Robot 5. I've already calculated the Jacobian, position and rotation error for the classic control method:
The method works fine ...
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What is the difference between the pose of a robot and the configuration of a robot?
Do "configuration" and "pose" means the same thing? If not what is the difference?
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Why does degree of freedom only consider continuous values?
In the book Modern Robotics Chapter 2 Configuration space, we are told that degrees of freedom only considers coordinates with real valued continuous range.
Why is this the case?
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Control Algorithms for Kinesthetic Teaching
There are several algorithms for post-processing of kinesthetically demonstrated motions for manipulators learning a task. However, I have failed to find papers/research work on modeling the ...
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Symbolic Representaion of Links and Joints: How to sketch complex manipulators using simple symbols?
In some papers and books we can see that authors using symbols to represent robot arms. My question is, is there a convention for such sketches? If so could you provide a reference which shows how ...
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Computing the Jacobian Matrix -- chain rule?
I am learning about robot kinematics and the Jacobian matrix, and I'm trying to understand how to compute the Jacobian matrix given a kinematic chain, such as a robot arm. I understand the theory ...
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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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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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