Questions tagged [kinematics]

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

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1answer
149 views

Does Inverse Kinematics need the current joint angles?

I had a discussion with a study colleague about the IK solver. The question was: Does IK need the current joint values to calculate the requested position. I think it doesn't need it. From my ...
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2answers
11k views

Running my 3 DOF Inverse Kinematics Code: Works in MATLAB, not in Python

I asked a question similar to this earlier, but I believe I have a new problem. I've been working on figuring out the inverse kinematics given an x,y,z coordinate. I've adopted the Jacobian method, ...
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3answers
841 views

Confusion about order of homogeneous transform multiplication

This is my first post here, so if I unknowingly vioated any rules, mods are welcome to edit my post accordingly. Ok, so my problem is that following Craig's conventions, I can't seem to find the ...
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1answer
657 views

Real-time TCP position/pose control on a robotic arm such as YuMi: recommendation to calculate IK/Inverse Jacobian?

I plan to make a mouse or a gesture control robot like this video on YouTube : ABB Externally guided motion.  For a 6-axes robot, I could implement it by using ABB’s EGM (Externally Guided Motion) ...
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0answers
1k views

Any free or paid software for graphical drawing of Robotics Kinematic Scheme? [closed]

I have been searching for days looking for a dedicated software for easily draw kinematic diagrams of robotics like this: I came by this software but it is a bit hard to grasp. Is there any GUI based ...
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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 ...
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3answers
608 views

Forward kinematics equations

I'm stuck at computing forward kinematics equations. I have configuration of the first two joints like on the following image: Transformation from the origin to the first joint basis is trivial: ...
2
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1answer
92 views

How big is the set of kinematics singularities?

Suppose we have an $n$-DOF robot manipulator and let $q \in \mathbf{R}^n$ denotes a robot joint configuration. Then a singular configuration $q'$ is a configuration at which the Jacobian $J(q')$ does ...
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1answer
4k views

Matlab Inverse Kinematics 6 DOF

I'm trying to write an inverse kinematics Matlab code for a 6 DOF robotic arm that has the following link parameters: Twist angle (alpha): [-90, 0, 90, -90, 90, 0] ...
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0answers
79 views

Inverse kinematics for a robot lamp

I've been working on a robot lamp. Looking something like this: So i had a few questions. I've decided to simplify the movements by giving the head a fixed orientation like you see in the picture. ...
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1answer
236 views

How to Calculate the Translational and Rotational Velocity of a 4 Wheeled Robot?

I have a robot with a 4 wheel drive using mecanum wheels to allow for more mobility. For the engineering documentation I am looking to find both the translational velocity and rotational velocity of ...
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4answers
868 views

Forward and Revers Kinematics For Modified Hanging Plotter

I'm building a modified version of the standard hanging plotter (v-plotter). The basic idea is that you have two cables hanging from stepper motors which form a triangle supporting the pen at the tip. ...
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1answer
128 views

Integrating Forward Kinematics Map

Let the forward kinematics map be denoted by $\mathcal{F}$ such that $\mathcal{F}: \theta \in \mathbb{R}^{n} \rightarrow g \in SE3$ Let the minimal representation of $g$ be given by $x \in \mathbb{R}...
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1answer
200 views

Velocity Relation for Parallel Robots

In my course of "Advanced Robotics" with "Fundamental of Robotic Mechanical Systems" as the reference book I saw the following equation as the velocity relation for parallel manipulators such as the ...
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1answer
628 views

showing error while using inverse kinematics “ikine” for 4 dof robotic arm

I want to do forward dynamics but before that I got struck in inverse kinematics for 4 dof. My code is given below: ...
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1answer
56 views

I found the matrices but can't find the inverse kinematics angles

I need to find inverse and forward kinematics of Mitsubishi RV-M2 as a homewrok. I found the forward kinematics part. But I got stuck in inverse kinematics. Teacher said we can think that wrist ...
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1answer
707 views

What kinematic equations should I use for Kalman filter state propagation in IMU based quadcopter navigation?

I am working on implementing a Kalman filter for position and velocity estimation of a quadcopter using IMU and vision. First I am trying to use the IMU to get position and velocity. In a tutorial [1] ...
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2answers
76 views

What is the top speed of a four legged robot? [closed]

In Neal Stephenson's novel "Snow Crash", a robotic/cybernetic creature known as a "Rat Thing" looses its bounds and runs to rescue another character. The Rat Thing is portrayed at moving over 700 ...
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2answers
870 views

Finding rotation quaternion

I am trying to use a quaternions for robotics and there is one thing I don't understand about it. Most likely because I don't understand how to define position with quaternions and how to define ...
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1answer
61 views

Is there any robot stability control equation that describes the relation between velocity of the robot and its orientation?

Let’s assume at time t a moving robot (e.g. PIONEER 3-DX) changes it’s steering angle by $25^{\circ}$. Obviously, in order to maintain stability and avoid overturning, the robot must reduce its ...
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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 ...
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2answers
1k views

Difference between an underactuated system, and a nonholonomic system

What's the difference between an underactuated system, and a nonholonomic system? I have read that "the car is a good example of a nonholonomic vehicle: it has only two controls, but its configuration ...
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1answer
108 views

Fit robot simulator to robot

I have odometry data $(x, y, angle)$ of a real two-wheeled robot, who received control commands $(forward speed, angular speed)$. Now I want to code a motion model (in C++ (/ROS)) which should follow ...
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1answer
176 views

Determining the graspable range of a robot arm

I have a 6 DOF robot arm, and I want to do some object grasping experiments. Here, the robot is rigidly mounted to a table, and the object is placed on a different adjacent table. The robot must pick ...
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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 ...
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2answers
99 views

Velocity derivatives using Quaternions [closed]

How to compute the angular and linear velocities Quaternions? I am new to this area and although I have studied the algebra I am unable to understand how to compute the velocities.
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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 ...
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1answer
357 views

Rostock Delta Robot 3D Printer Degrees of Freedom (DOF)

What is the degrees of freedom (DOF) of the Rostock delta robot 3d printer (delta mechanism that consists of three prismatic joints)? Here's the link to the delta mechanism I'm referring to: https://...
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1answer
126 views

Mobile robot algorithm implementation error

I am working in reproducing a robotics paper, first simulating it in MATLAB in order to implement it to a real robot afterwards. The robot's model is: $$\dot{x}=V(t)cos\theta $$ $$\dot{y}=V(t)sin\...
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2answers
387 views

Distance calculation with two robots and two obstacles

I have a problem with two robots and two obstacles in a space. Each robot can communicate its measurements to the other and can measure angles and distances. The two obstacles in the environment are ...
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2answers
99 views

I'm looking for hands-on experience with different types of leg and hip designs for walking robots [closed]

I'm looking to find out, How do human-like legs compare to chicken legs and four-leg systems. In terms of cost, performance, speed, strength and accuracy. I'm interested in things like speed, agility,...
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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 ...
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1answer
442 views

convert toolframe coordinate to world frame coordinates?

I am not sure how i should explain this, I am looking for a way to plot the trajectory an robot arm. An object is seen from the toolFrame frame, but how do I plot the position of each joint, such ...
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1answer
49 views

Principle of virtual force - General help in understanding / explanation

I'm an Electronics student taking a module in Robotics. From the example, I understand line 1 as the Jacobian is found from the time derivative of the kinematics equation and such relates joint ...
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0answers
41 views

How to determine the angles between a UAV and a sphere

I have an UAV modeled in three dimensions with let's say position coordinates $p_{uav} = (x_1,y_1,z_1)$ that is moving in a direction $d = (d_x,d_y,d_z)$ and a moving obstacle modeled as a sphere with ...
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1answer
503 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 ...
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1answer
456 views

Dynamic model of a robot lifted by a balloon (Multibody system)

I'm having a hard time trying to understand how to obtain the dynamic model for a system similar to the image. The balloon is a simple helium balloon, however the box is actually an aerial ...
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1answer
329 views

Are operational space and joint space dependent on each other?

Some questions about this, my friends and I argued with this problem. Are operational space and joint space dependent on each other? I know that $x_e$ (end effector's pos.) and $q$ (joint var.) can ...
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1answer
206 views

List of books similar to Thrun's Probabilistic Robotics for robot mechanics and manipulation [closed]

What? Put together here a list of books (like the one for C/C++ on StackOverflow) that are spiritually similar to Sebastian Thrun's Probabilistic Robotics for robotic manipulation and mechanics. Why?...
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3answers
782 views

How many DOFs required to define a 3D pose

I understand that to be able to define point in 3D space, you need three degrees of freedom (DOFs). To additionally define an orientation in 3D space, you need 6 DOFs. This is intuitive to me when ...
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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 = ($q_1$,$q_2$,$...
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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 ...
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3answers
3k views

How to find kinematics of differential drive caster robot?

I'm working on a little project where I have to do some simulations on a small robot. I my case I'm using a differential-drive robot as one of the wheels of a bigger robot platform (which has two ...
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0answers
75 views

Accurate technique to locate position? [closed]

What is the most accurate way to locate the position and orientaion of the body during some motion (rotation and translation)? I need to track the body very precisely, the required accuracy is 100-...
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1answer
5k views

How to perform odometry on an arduino for a differential wheeled robot?

I am using a differential wheel robot for my project. I need to know the current coordinates of the robot with respect to it's initial position taken as the origin. I m doing the computation on an ...
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1answer
2k views

DH parameters and Kinematic Decoupling

Is it possible to decouple a 5DOF manipulator? This question I asked earlier and I believe I got the right answers but I never show the drawings of the manipulator and now I'm hesitating during setup ...
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1answer
107 views

Relative orientation of two robots

Given two robot arms with TCP (Tool Center Point) coordinates in the world frame is: $X_1 = [1, 1, 1, \pi/2, \pi/2, -\pi/2]$ and $X_2 = [2, 1, 1, 0, -\pi/2, 0]$ The base of the robots is at: $...
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2answers
1k views

Kinematic decoupling

Is kinematic decoupling of a 5DOF revolute serial manipulator also valid? The three last joints is a spherical joint. Most literatures only talks about decoupling of 6DOF manipulators. Thanks in ...
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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 ...
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3answers
693 views

Algebraic and geometric in inverse kinematic

I'm just wondering that is there any case that when algebraic way can't solve the problem while the geometric can ? Cause I'm working on a 2DOF robotics arm This one, I know the length of L1 and L2, ...