Questions tagged [manipulator]

manipulator is a device used to manipulate materials without direct contact.

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33 views

C space for R5 manipulator

Trying to create a collision avoidance model (RRT) for an RRRRR manipulator. I am unable to wrap my head around how to represent the same in configuration space. Anything upto 3 joint variables is ...
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1answer
44 views

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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63 views

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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23 views

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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32 views

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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2answers
86 views

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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1answer
33 views

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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46 views

Design optimization method using indices

There are several methods like manipulability and conditioning index for design optimization kinematics performance, but these methods rely on the singular values of the jacobian matrix. I described ...
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1answer
46 views

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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1answer
53 views

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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77 views

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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35 views

Quaternionic feedback for for cartesian impedance control

I've seen that there are plenty of ways of generating orientation errors with quaternions. But the one I've seen most often is the following: For example, say that for a quaternion $Q = \{\eta, \...
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62 views

SLERP velocity and acceleration (3d Orientation interpolation)

Hey guys I am quite new to quaternions and I am a bit unsure as to how to use them. How are the velocities and accelerations trajectories determined using quaternions? I have been using slerp to ...
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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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48 views

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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1answer
54 views

How do I assign the origin of the frames in the Denavit Hartenberg convention?

I am studying the Denavit Hartenberg and to practice I am using the following manipulator: I have been able to assign some of the frames almost correctly, but i did some mistakes I cannot understand. ...
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85 views

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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DH Notation for Bend End Effector of RRR Articulated Arm

Hello, I want to ask about the DH notation for this RRR Robot with special end effector (See in the picture). I have a problem when writing the DH notation from join 3 to the end effector. the L shape ...
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56 views

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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1answer
30 views

Why applied joint torque will affect another joint?

I want to ask a very simple question. For the robot dynamics Newton-Euler algorithm, suppose there is a two-link planar robot, we can write the simple dynamic equation form as $M(\theta)\ddot{\theta} ...
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21 views

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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40 views

Newton-Euler Inverse Dynamics by Screw

I paste this algorithm from textbook Modern Robotics P294 in chapter 8: This is coordinate invariance of Newton-Euler equations. In the textbook, they use the ...
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1answer
140 views

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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2answers
30 views

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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28 views

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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48 views

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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147 views

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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1answer
57 views

How to define the degrees of freedom of a flexible manipulator?

Consider a cable-driven flexible manipulator which has 3 cables. Consider the 3 cables to be actuated by 3 motors. Assume that by pulling the three cables in different configurations, we can span the ...
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2answers
65 views

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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1answer
51 views

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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1answer
19 views

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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22 views

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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1answer
79 views

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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2answers
56 views

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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1answer
20 views

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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1answer
164 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 ...
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1answer
33 views

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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107 views

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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2answers
433 views

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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1answer
40 views

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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180 views

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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110 views

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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1answer
43 views

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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1answer
263 views

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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2answers
56 views

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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2answers
222 views

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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39 views

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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1answer
767 views

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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144 views

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 ...