Questions tagged [kinematics]

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

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How to find angular velocity using pure pursuit algorithm?

I have implemented the pure pursuit algorithm for my differential wheeled robot as described in the following paper: http://www.enseignement.polytechnique.fr/profs/informatique/Eric.Goubault/MRIS/...
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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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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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Deduce all possible configuration for a given CONF param FANUC

I am working on the "CONF" parameter of FANUC Robots. The "CONF" param determine the pose of the robot (maybe to have only one inverse kinematics solution). This configuration is ...
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Ground based path generation from RGBD camera

How does one generate a trajectory for a ground vehicle using an RGBD camera? For a drone it's simpler since you're not constrained by having to move on the ground but it's not clear to me how ...
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How can I find a robot's distance from an object given FOV, bounding box measure, and image width and height in pixels?

The robot is standing in the middle of the arena. I am confused on how to convert the pixels into a real life distance and how to use the bounding box. Starting help is appreciated.
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How to do a relative rotation of a cuboid such that the longest edge is upright?

I am using pybullet. I have a cuboid with half extents [4,2,1] corresponding to x,y,z dimensions. I rotate this cuboid around the z world axis theta and also translate it by [0, 0, .65]. I take a ...
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Degree of maneuverability mobile robot

According to the traditional kinematic theory for mobile robots [1][2] a mobile robot with a steerable wheel and two passive casters presents a $\delta_m=2,\delta_s=1,\delta_M=3$. This is easy to ...
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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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Link collision avoidance for redundant manipulator

I am trying to have my robot arm follow a trajectory while avoiding collisions between obstacles and the robot links. The way I go about it is to find the closest point on the robot arm, and treat the ...
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Can someone help me understanding reference frames in OxTS data in KITTI Vision Benchmark dataset?

If anyone has worked with KITTI dataset, can you explain the reference frame used in roll pitch yaw values? I downloaded the raw data from this link: http://www.cvlibs.net/datasets/kitti/raw_data.php ...
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Formulas for calculating the passive joints angular velocities

We have the following parallel robot architecture: Positions of the vectors $u_i, v_i, w_i$, the angles $\theta_i$, angular velocity $\dot{\theta_i}$ and the Jacobian $J$, that mapping vector of ...
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About kineto-statics duality of the closed chain

I can't understand the content from the book "Robotics Modelling, Planning and Control", page 151. Suppose that there is a manipulator which has a closed chain. And Let $\textbf{q}_a$ actuated joint ...
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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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how to normalize PWM if the value exceeds the maximum speed limit

I have implemented inverse kinematics for nonholonomic mobile wheeled robots, and the RPM range of the motor that I used is -50 to 50, while for PWM is from 1300 to 1700. But in certain cases, the RPM ...
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Algorithm for orientation (pan/tilt) towards a moving point

Main Question: note: The code in this question is pseudo-code, I'm using Python, but my pseudo-code is a mix of Python and C++. I have a camera on the top of my robot's "head" which has pan and tilt ...
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Treatment of euler angles in quadcopter control

In most implementations of quadcopter control systems I've seen, each axis of the quadcopter is controlled independently. For example, to control the rate in the roll axis, the desired output is ...
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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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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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Can active sensor data be fed into an Autodesk Inventor Simulation?

I'd like to drive the position of various components within a virtual assembly based on sensor data being collected in real time from an external device. Does Inventor support such a setup? The goal ...
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Estimating the bycycle model using point sets from consucutive frames

I have two sets of points from two consecutive frames (restored from a video). The data represent points on the surface of a single-vehicle moving between frames. Points are in 3D and are assumed not ...
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Robot increases in length, trying to keep robotic along previous position trajectory

Sorry for the confusing title, this seems to be a difficult problem to concisely describe. I am working on a 50-DOF (yes, 50) robot that is comprised of "elbow macaroni" links that rotate ...
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VR: is it possible to calculate hand position relative to head based off these known orientations and lengths?

If we have 3, 9DoF IMUs for absolute orientation data on the: wrist upper arm forehead and we know the length of the: wrist upper arm shoulder to base of neck neck and we also know the global ...
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Problem with Inverse Kinematics Solver (Jacobian Inverse Method)

I am trying to create an inverse kinematics solver for my 4-dof (all revolute joints) robot using the inverse Jacobian Method. However, it does not seem to be working as the distance between target ...
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GPS + IMU data and kinematics equations

I have the following data Longitudinal acceleration, $a_x^{IMU}$ Lateral acceleration, $a_y^{IMU}$ Vertical acceleration, $a_z^{IMU}$ Yaw angle, $\psi$ Yaw rate, $\dot{\psi}$ Latitude, $\rightarrow ...
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Robot differential drive wheel speed

I would like to build a small robot. The robot will have 4 independent motors, one for each wheel. It will have a rear axle fixed and the front axle will be freely pivoting around its center, somewhat ...
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Trajectory optimal for quadcopter

I have defined a quadcopter that I control with a PID controller. The dynamics that define it are such. $T=mg+m\ddot{z}$ $\theta=\frac{\ddot{x}}{-9.82}$ $\phi=\frac{\ddot{y}}{9.82}$ As you can see I ...
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In MuJoCo why do some XML files have objects fall to the ground while others are just fixed above the ground?

Why do some models, or objects in a MuJoCo XML script fall to the floor while others don't? In the models files that come with the MuJoCo zip, the robot arm (arm26) does not fall to the ground while ...
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Trajectory following of 3-wheel omnidirectional robot

I created a three-wheeled omnidirectional robot on omni-wheels, there is also a program in which I can plot a trajectory when plotting a trajectory, such data are obtained (X, Y, Tangent X, Tangent Y, ...
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How to correctly determine the θi Denavit-Hartenberg parameter for a SCARA manipulator?

I am using Tsai's Robot Analysis (The Mechanics of Serial and Parallel Manipulators) and I am working on deriving the homogeneous transformation matrices for the SCARA robot with the assigned frames ...
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IK Jacobian is always a singular matrix

I am trying to solve an inverse kinematics equation for 6DOF system, 3 rotation and 3 prismatic joints. I am trying to solve using perturbation method, by adjusting each joint and calculating the ...
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Joint space trajectory script unclear

I have a script provided by The MathWorks Inc. that makes a robot end-effector follow both a task space and a joint space trajectory through several waypoints. These trajectories are then plotted in ...
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2 answers
173 views

Orientation Problem of a 4-DOF manipulator

As shown in figure, I have a 4-DOF manipulator. I want to control the robot such that the end-effector should always be pointing down no matter where the robot is in the end space. For the ...
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how to find the kinematic and dynamic model of the mechanism

enter image description here 5 links 4 revolute joints find the kinematic and dynamic model ,link 3 should be horizontal with ground and one end of link 1 and 5 there are sliders enter image ...
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Looking for a course (online?) RE: systems with XY stages

Using XY stages is common in many fields: 3D printing Genetics instruments semiconductor lithography automated microscope slide imaging See for example https://www.asml.com/en/technology/lithography-...
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199 views

Simple inverse Kinematic algorithm

I was looking for a simple inverse Kinematic algorithm that doesn't depend on eigen(doesn't work on my machine + dependency conflict never fixed it) Most of the code out in the internet is way to ...
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1 answer
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5 bar linkage hand exoskeleton

I have a project to design a hand exoskeleton for hand rehabilitation. The problem is that i'm thinked I only need the linkage mechanism with multiple 4 bar linkages. But because of human fingers ...
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1 answer
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How can I find the kinematics 2 differential drives attached together along their axes?

I have a system like shown in the diagram where 2 robots having differential drive are physically constrained together. Traditionally for a single robot, we find the Instantaneous center of curvature (...
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1 answer
72 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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From an end-effector trajectory to joints movements

let's assume that our robot consists of 3 degree-of-freedoms. In order to move the end-effector of this robot along a straight line, these 3 joints have moved as below: Now, if the desired end-...
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What is my last rotation matrix for the last three angles when i have found the first three when doing inverse kinematics to a 6dof robot?

I am doing inverse kinematics for a 6dof robot. I have used the geometrical method to describe the angles from one to three. I have trouble doing the next part. I know I that I have found the ...
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Maximizing the Coefficient of Friction Between Two Surfaces

I am new to this site so please let me know if I can improve my question. A component of a robot I am designing includes a four-wheeled carriage that travels linearly on an aluminum surface. The ...
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NodeMCU ESP-12E Wont Print to Serial in Arduino IDE

So, im using a ESP-12E nothing special about it, to try and run this code i found from a custom library example. ...
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I want to Calculate the Joint Velocities and Angular Accelerations of 5 DOF Youbot kuka robotic arm

I'm working on an assignment where I need to derive Velocity Kinematics for 5 DOF Youbot kuka robotic arm manipulator. I want to Calculate the Joint Velocities and Angular Accelerations of 5 DOF ...
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Problem with solution (equation) for wrist singularity

In my textbook about industrial robots it says that if the angle q5 in this robot is equal to 0, there are infinite solutions for the angles q4 and q6. I understand this part, but I have a problem ...
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What do I need to know about the dynamics of an industrial robot?

Apart from kinematics, what do i need to know about the dynamics and other things of a robot in order to calculate the angles of the joints for positions of the end effector exactly? that means: if i ...
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Gyroscope signal when mounted on a deflated tire

Before I do the experiment, I am a bit confused about the expected signals provided by a 3-axis gyroscope (angular velocities vs. time) mounted on the edge of a (slightly) deflated car tire when the ...
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1 answer
268 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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