Questions tagged [manipulator]
manipulator is a device used to manipulate materials without direct contact.
156
questions
2
votes
2
answers
751
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 ...
- 344
6
votes
1
answer
348
views
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 ...
- 344
1
vote
1
answer
94
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 ...
- 469
3
votes
1
answer
1k
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. ...
- 469
2
votes
2
answers
269
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 ...
- 469
1
vote
0
answers
485
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 ...
- 344
2
votes
2
answers
93
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} ...
- 187
1
vote
0
answers
50
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.
- 121
0
votes
1
answer
174
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 ...
- 187
5
votes
1
answer
443
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)\...
- 344
1
vote
2
answers
42
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 ...
2
votes
0
answers
218
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 $...
- 155
0
votes
2
answers
180
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 ...
- 469
3
votes
2
answers
372
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 ...
- 469
2
votes
1
answer
258
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 ...
1
vote
2
answers
108
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 ...
- 469
0
votes
1
answer
646
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 ...
- 469
0
votes
1
answer
29
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.
- 187
1
vote
1
answer
66
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), ...
- 187
0
votes
1
answer
100
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 ...
- 629
0
votes
2
answers
556
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 ...
- 313
0
votes
1
answer
56
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?
- 3
3
votes
1
answer
1k
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 ...
- 344
0
votes
1
answer
46
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$...
- 113
0
votes
1
answer
386
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 ...
- 21
2
votes
2
answers
2k
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 ...
- 21
0
votes
1
answer
56
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 ...
- 111
0
votes
2
answers
523
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?
4
votes
2
answers
438
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} &...
0
votes
1
answer
56
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 ...
- 407
0
votes
4
answers
2k
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 ...
- 31
1
vote
2
answers
341
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 ...
- 11
1
vote
2
answers
688
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 ...
- 19
1
vote
0
answers
56
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 ...
- 326
5
votes
1
answer
4k
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?
2
votes
1
answer
408
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 ...
- 21
0
votes
1
answer
111
views
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?
1
vote
0
answers
25
views
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 ...
- 671
2
votes
2
answers
1k
views
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", ...
- 123
0
votes
1
answer
258
views
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 ...
0
votes
1
answer
4
views
The weight on position constraint for link is near zero. Setting to 1.0
Hi,
While trying to move a robotic manipulator to a new pose (using MoveIt!), in order to move to the Next Best View of the manipulator's workspace using the YAK package, I repeatedly get this warning ...
aaditya_saraiya
0
votes
1
answer
495
views
Which motors are specifically used for UR3 (Universal robot arm) [closed]
I am looking for the specification of UR3, peak torque and rpm.
3
votes
2
answers
1k
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 ...
0
votes
1
answer
321
views
zero-g mode for UR10 gravity compensation
I would like to freely move my UR10 arm in response to an external force, just like the zero-g mode for Baxter robot, which can be activated by holding its wrist. The Baxter documentation on zero-g ...
- 136
0
votes
1
answer
1
view
REQUIRED process [open_manipulator_dynamixel_controller-2] has died!
I just tried to operate open manipulator system by using two motor(MX-106).
When I launch that code, the following error occur.
...
epiphanyan
2
votes
0
answers
814
views
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 ...
- 21
2
votes
1
answer
3k
views
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 ...
- 244
1
vote
1
answer
200
views
Urdf as a way to model dynamics?
Since urdf format serves the purpose of kinematic model but also extends for dynamical properties such as mass,moment of inertia and centre of masses, can it be considered a viable dynamical model of ...
2
votes
1
answer
488
views
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....
- 193
2
votes
1
answer
562
views
Dynamics of a robot manipulator with a force acting on the end-effector
I have this exercise
The dynamic model is
$B(q)\ddot{q}+S(q,\dot{q})\dot{q}=\tau+\tau_k$
Where $B(q)$ is the inertia matrix, $S(q,\dot{q})\dot{q}$ are the centrifugal and Coriolis terms, $\tau$ is ...
- 33