Questions tagged [kinematics]

Kinematics is the branch of mechanics dealing with the motion of points and objects.

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14
votes
2answers
12k views

Calculate position of differential drive robot

How do you calculate or update the position of a differential drive robot with incremental sensors? There is one incremental sensor attatched to each of the two differential wheels. Both sensors ...
19
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4answers
9k views

How can the inverse kinematics problem be solved?

The forward kinematics of a robot arm can be solved easily. We can represent each joint using Denavit–Hartenberg transformation matrices. For example, if the $i^{th}$ joint is a linear actuator, it ...
8
votes
2answers
3k views

What are the advantages of using the Denavit-Hartenberg representation?

When one wants to model a kinematic chain and in particular define the frames attached to each body, it is common to use the Denavit-Hartenberg parameters. What are the advantages of this ...
3
votes
3answers
3k views

jacobian of Abb irb140 robot

Can someone please help me with the jacobian matrix equations for Abb irb140 robot. Or an easy way by which I can derive it given the DH parameters. I need it to implement some form of control that am ...
6
votes
2answers
2k views

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 ...
4
votes
2answers
2k views

How much accuracy could I get position tracking with a 3-axis accelerometer and gyro sensor, and compass, and how would I do it?

Given a 12' x 12' field (4m x 4m), a reasonably cheap 3-axis gyro sensor and accelerometer, and compass, I plan to design a device capable of tracking its position to sub-centimeter accuracy for a ...
8
votes
3answers
4k views

Forward Kinematics/D-H parameters for perpendicular joint axes

I am trying to compute forward kinematics of the Kuka youBot using DH convention: http://www.youbot-store.com/youbot-developers/software/simulation/kuka-youbot-kinematics-dynamics-and-3d-model The ...
7
votes
2answers
3k views

How to calculate the right and left speed for a tank-like rover?

I am trying to control the Rover 5 robot using an Android app with a touch-based joystick control in the app UI. I want to calculate the speed of the left and right motors in the rover when joystick ...
3
votes
1answer
3k views

How to design a differential steering mechanism?

I want to give my robot a differential mechanism for the system of turning and steering. Considering the case of turning a right-angled corner, the robot will achieve this by following a gradual ...
2
votes
2answers
191 views

Angle to a circle tangent line

I want to simulate the detection of a moving object by a unicycle type robot. The robot is modelled with position (x,y) and direction theta as the three states. The obstacle is represented as a circle ...
6
votes
2answers
13k views

Position Control vs Velocity Control vs Torque Control

Please can somebody explain to me the difference between Position Control, Velocity Control, and Torque Control? Specifically, I am thinking in terms of a robot arm. I understand that position control ...
17
votes
2answers
20k views

Computing the Jacobian matrix for Inverse Kinematics

When computing the Jacobian matrix for solving an Inverse Kinematic analytically,I read from many places that I could use this formula to create each of the columns of a joint in the Jacobian matrix: ...
4
votes
1answer
1k views

Velocity Model Motion in Matlab (Probabilistic Robotics)

I want to implement the velocity motion model in Matlab. According to Probabilistic Robotics page 124, the model is as following \begin{align*} \hat{v} &= v + sample(\alpha_{1} v^{2} + \...
6
votes
2answers
2k views

Solving Inverse Kinematics with Gradient Descent

I am trying to implement my own inverse kinematics solver for a robot arm. My solution is a standard iterative one, where at each step, I compute the Jacobian and the pseudo-inverse Jacobian, then ...
9
votes
3answers
2k views

With a 6-axis robot, given end-effector position and range of orientations, how to find optimal joint values

Given a six-axis articulated robot arm holding a tool at its end-effector, if I have a desired tool position and tool orientation, there will be exactly 1 solution to the inverse kinematics equation ...
6
votes
1answer
1k views

Hand Eye Calibration Solver [closed]

I have a rig for which I have a pretty good estimate of the static transformation between the camera and a joint based off of the CAD. It has some errors though and I was hoping to fix it by doing a ...
4
votes
3answers
2k views

Jacobian-based trajectory following

I would like to control my 7 DOF robot arm to move along a Cartesian trajectory in the world frame. I can do this just fine for translation, but I am struggling on how to implement something similar ...
3
votes
2answers
747 views

Robot arm reachability of a pose in Cartesian space

Given a set of robot joint angles (i.e. 7DoF) $\textbf{q} = [q_1, ... , q_n]$ one can calculate the resulting end-effector pose (denoted as $\textbf{x}_\text{EEF}$), using the foward kinematic map. ...
0
votes
1answer
6k views

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 ...
12
votes
2answers
3k views

Differences between Ackermann steering and standard bi/tricycles concerning kinematics?

I got the following homework question: What are the general differences between robots with Ackermann steering and standard bicycles or tricycles concerning the kinematics? But, I don't see what ...
9
votes
1answer
2k views

How do I convert link parameters and angles (in kinematics) into transformation matrices in programming logic?

I'm doing robotics research as an undergraduate, and I understand the conceptual math for the most part; however, when it comes to actually implementing code to calculate the forward kinematics for my ...
3
votes
1answer
491 views

inverse kinematics for 6 jointed robots

I am a uncertain about how to compute the right homogeneous transformation matrix to compute an inverse kinematic Q-configuration. Looking at robot like this Where at the end of this robot I have ...
3
votes
3answers
2k views

Forward kinematic computing the transformation matrix

I am the moment trying to compute the transformation matrix for robot arm, that is made of 2 joints (serial robot arm), with which I am having some issues. L = 3, L1 = L2 = 2, and q = ($q_1$,$q_2$,$...
2
votes
1answer
962 views

calculating differential drive robot ICC position

I don't understand how to calculate the ICC position with the given coordinates. I somehow just have to use basic trigonometry but I just can't find a way to calculate the ICC position based on the ...
1
vote
2answers
2k views

How to find the body jacobain, for each link in a robot manipulator?

The links twist could be obtained, and thus The spatial manipulator Jacobian could be done, but when it comes to the body Jacobian, it is becomes difficult. Moreover, the adjoint transformation ...
1
vote
1answer
265 views

Optimization of link lengths for 3R serial manipulator

I am trying to formulate an optimization problem for determining link lengths of 3R manipulator shown in picture below, Following are the constraints, Robot arm should be reachable at point x = 100, ...