Questions tagged [robotic-arm]

The arm tag is intended to be used for questions relating to robotic arms from, small hobby arms with only 1 or 2 degrees of freedom to large industrial robots with complex joint assemblies. For the ARM CPU, use the tag arm-cpu.

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6 views

Controlling Actuated Robot Hand in Underactuated Manner

We have an allegro hand in our robot, and it is in actuated behavior. In other words, each joint is controlled one or more than one actuator, that is motor. There are 3 actuators for each finger, ...
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22 views

Do I need to use Inverse Kinematics if I have the coordinates of all joints?

So I have the positions of all the joints (x,y,z) of a robot arm. I need to calculate the angles of the joints to feed them to another similar robot arm. I cannot get the angles from the robot I need ...
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15 views

The wide range of suction cups

I noticed that there are heaps of suction cup types for vacuum arms, but how to tell which cup type should be used when? The way I read it is, for bigger and heavier objects, a cup with a large ...
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1answer
35 views

Robotic arm chassis

I've been curious about how the plastic chassises of the robotic arms in robotic competitions are manufactured. For instance, the following arms clearly have 10-20 plastic parts each, if not more: ...
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10 views

Effective forces on an object for grasping

For example, a robot or a humankind is grasping an object such as a bottle. Which forces are effective on that bottle ? This is my opinion: When we grasp a ...
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24 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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31 views

Grasp stability of a robot

I have read some researches and sources about "grasp stability", but I don't understand what it is exactly. If a grasp is stable, does the hand grasp the object perfectly, accurately or strictly? ...
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1answer
82 views

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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25 views

moveit! trajectory execution aborted

I'm trying to send a custom arm to a pose through moveit_commander_cmdline.py, it fails after sending to the said pose using " go default_pose" and returns an error. ...
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25 views

Inverse Kinematics of Puma 566 giving low angle results with DH convention

I am new at the robotics area, and i need to deliver an activity until this week in my college based to solve the inverse kinematics problem from an article that doesn't have any code done, and after, ...
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1answer
20 views

All Joint Angle values not converging to desired set point (I am using Roy Featherstone's Spatial Toolbox)

I need the robot joint angles to become the same as given (desired) joint angles. The kinematics and dynamics (used Spatial Toolbox) are correct and the motor models are realistic too. But out of 3 ...
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1answer
21 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 ...
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1answer
27 views

Non-planar robot Dynamics error using Roy Featherstone's Spatial toolbox

I am using this code to test robot dynamics of above robot using Spatial Toolbox function: FDab(rob, [0;0;0], [0;0;0], [0;0;0]) %a_grav = [0,0,-9.81] But it ...
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1answer
28 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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11 views

Using Simulink Interpreted MATLab fcn for robot dynamics using Robotics Toolbox

I am using Interpreted MATLab fcn to compute forward dynamics. I am using code of accel in which I have added my robot model in the beginning, making the accel function: ...
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27 views

Which motor is suitable for generating a constant pressure on objects?

I want to build a simple arm that can generate a pressure on a small object (a force of 50-100 gram is enough) and let go of it very quickly. Which motor can be used for this?
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15 views

3 DOF robot torque not converging Robotics Toolbox

I have a Simulink model in which desired torque is [0;0;0] and current torque should converge to zeros too. But I am getting oscillatory torque as output. This is the block diagram of what I am ...
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1answer
19 views

Joint torque sensor vs end-effector force sensor

I am trying to understand the difference between joint torque sensors, and force sensors, in a robot arm. From what I understand, joint torque sensors estimate the torque at each joint, whereas a ...
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1answer
48 views

3-DOF Robot Dynamics error in Robotics Toolbox

I am trying to compute dynamics of 3 DOF robot using Robotics Toolbox by executing this code: robot.accel(q, zeros(1,3), zeros(1,3)) But I am getting this error: ...
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1answer
49 views

Simulating a robot

I try to simulate a robot, but with a GUI. I can make a simulation using pyopengl to simulate the movement of robot, but I cannot make the GUI with that. I need to make it easier to simulate, analyze, ...
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34 views

Force Controller for robotic manipulation

I want to implement a force controller but I don't understand some concepts here. I saw some books that say the output torque command of the force controller and the impedance controller will be ...
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1answer
27 views

Native ROS vs ROS compatible via API

I am looking to buy a cobot for a research project (budget about 20k€). I happened to see some cobots (e.g. Mara) that claim running ROS natively, some others (e.g. Aubo i5) that is compatible with ...
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1answer
84 views

Inverse Jacobian to find joint angles

I am trying to implement a joint space control with the UR5 in MATLAB/Simulink and have programmed the forward kinematics of the same. Now, I want to find out the joint angles of the manipulator using ...
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2answers
49 views

Robotic arm for university student [closed]

Can anybody recommend a robotic arm to be possibly coupled with VR to be used for educational purposes for university students within a bucket of about 15000€?
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1answer
44 views

How to render a robotic arm in Unity?

As part of a research project, I'm creating synthetic data, using the Unity engine. I have the final pose of a robotic arm (6 params: 3 for orientation, 3 for location/position), and also a .ply file ...
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1answer
73 views

UR5 Visual servoing(image based, eye in hand)

I am implementing IBVS on a UR5 using ROS. The algorithm works very well in linear X, Y and Z and omega Y. When I try to add a fifth axis(omega X or Omega Z), the robot jerks heavily and goes into ...
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1answer
57 views

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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1answer
39 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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1answer
54 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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1answer
33 views

Rotation at SerialLink.teach Robotic Toolbox

Im using robotic toolbox to simulate my robot, but i always confused when i see the value of rpy. It always different if i compare with tr2rpy and tr2eul. What kind of rotation used in SerialLink....
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0answers
38 views

Any way to program a robot remotely?

So Udacity, Kuka and KIT are/were offering a Kuka challenge. Basically, the participants got to write code and run it remotely on a Kuka robot based in the KIT labs in Germany and submit their code ...
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1answer
37 views

Robot arm with steppers - speed

I am using a 5 axis Robot arm (Robolink robot from Igus) to perform some 3D printing routines. By now I am trying to use them and have him have some good position (and speed) control. The robot is ...
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2answers
32 views

Lifting robot that moves like a plotter

I'm looking for what a robot that moves like a plotter but can grab a load up to 1kg with a claw, lift, rotate and place in another location within its range. What is this type of robot called?
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1answer
41 views

Explanations about inverse kinematic

I am currently designing a 2D simulation of a 3DOFs robotic arm in order to develop a better understanding of inverse kinematic (so as to avoid breaking more components than necessary) but despite my ...
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2answers
36 views

Free Multibody Dynamics Software?

I'm working on modelling a feller buncher, its end effector consists of a saw to cut trees and claws to bundle them together. I'm looking for a free/open source software that can simulate dynamics of ...
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1answer
29 views

Force controller with feedback issues

I'm implementing a force controller on a robotic arm, where the force input comes from torque sensors in the joints. I have calculated the cartesian force on the end-effector from the joint torques, ...
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1answer
75 views

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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2answers
55 views

Calculate the inertia matrix of complex robotic mechanism

Motor, irregular rigid body of Different materials Forming a single robotic. For example, Industrial robot, every geometric shape of the link is very complex. But we can find inertia matrix form CAD ...
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4answers
155 views

Why my robot is lying down in gazebo simulator?

this is my first post about ROS and Gazebo also I am new in ROS. I spawn KUKA robot in Gazebo using urdf file from KUKA github repository following answer from this question I spawned my urdf file in ...
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1answer
50 views

vision guided robotic arm always required 6d pose of object? [closed]

I have an object like attached in image. It is hanging vertical (its position may change but static object) and I want to grasp it using 6DOF Robotic arm. I am Using camera to detect object. I am ...
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0answers
29 views

How to add some more feature for this simulink model

After some research Robotic hand simulation in MatLab? After some motivation, I have tried to go inside Matlab Simulink and was able to do this :- https://drive.google.com/open?id=...
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2answers
58 views

How are shells for robotic arms made?

I wonder how the shells of robotic arms are usually made. By the shell, I mean this: This is taken from the project here, which is a University project. If the shells were injection moulded, how ...
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1answer
39 views

What is the best adaptive controller for robotic arms?

I have a question that lays on practical experience. What is the best adaptive controller for a robotic arm? Self Tuning Regulator (STR) Model Reference Adaptive Controller (MARC) Adaptive Model ...
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2answers
66 views

Making a motor controlled joint passive

Anyone know of a good (and economical) way to make a motor controlled arm become a passive link on trigger? That is, the joint can be active (motor controlled) or passive (rotate freely). The tip of ...
2
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2answers
146 views

Finding correct RPY for approaching a known point on a plane

I have a robot with 6 DOF that I want to use to grab a hanging sheet at a specific point near its edge. The grip needs to be perpendicular to the edge and co-planar with the point of course. I have ...
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1answer
31 views

Why my stepper motor doesn't move when I attach a blade?

I wanted to use the NEMA 17 stepper to drive a blade/flapper that I have custom made for some physical application.As soon as I tighten the screw,the motor stops rotation in the usual way. Don't have ...
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1answer
74 views

3D Inverse Kinematics Jacobian Construction

I am following this article: Overview of Jacobian IK From the link, an example says: O is a pose vector which represents the initial orientation of every joint And following this, it gives an ...
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1answer
69 views

Gravity compensation

I am just getting curious about this gravity compensation technique. If we could compensate the force generated by the gravity (by feeding in the exact amount of force into the opposite direction), ...
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1answer
43 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 ...
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1answer
20 views

how to plugin orientation of 6R robotic arm in inverse kinematics

I had all the DH parameters and calculated transformation matrix. From that I know the end-effector value position. But I don't understand how to integrate orientation.