# Questions tagged [kinematics]

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

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### 3D Inverse Kinematics Jacobian

I am reading up on inverse kinematics and have a few questions I hope could be answered. This example is from a 3-revolute-joint, where $E$ is the end effector and $G$ is the goal position of the ...
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### Finding Mass/Inertia Matrix of a robot

Hi I am trying to model my humanoid robot. The general EoM is $M(q)\ddot{q}+C(q,\dot{q})+G(q)=U$ I know $M(q)$ is Inertia matrix which depends on joint positions $\textbf{q}$. However, I am having ...
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### Why is the endeffector of a delta-robot on the slant?

A delta-robot is a nice design for a robot, because it allows to separate the motor from the moving parts. As a result, large and heavy motors with 800 Watt can be used and at the same time the ...
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### 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....
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### 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 ...
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### Why using screws instead of homogeneous transforms in kinematics and dynamics?

Can anyone give a justification for using screws (twists, wrenches) instead of the traditional approach (rotation matrices, homogeneous transforms)? Even if screws are more compact, the situation gets ...
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### 2DOF arm with quick movement: Stepper, servo, or DC motor?

To make a two degree of freedom arm capable of speeds needed to play air hockey, how should the arm be controlled? I'm wondering about speed vs accuracy. The following image is from a project ...
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### How to create push and pull mechanism using Servo [closed]

How do I create a push and pull mechanism using a standard hobby servo? Eg. SG-5010 Preferably without the need of 3D printing.
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### Finding Joint speeds for each joint of a 6DOF arm (UR10) using the Inverse Jacobian

Background: I have access to a UR-10, 6DOF robotic arm through my school (I'm very new to robotics). I know the desired set of linear speeds that I want in the x,y, z-direction in terms of the end ...
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### Creating linear end effector motion using joint speeds: Converting tool speed to joint speeds

Background Information: I'm new to robotics and my school currently has access to a 6DOF Universal Robot (UR-10). I'm programming it using its scripting language URscript and the arm has these two ...
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### Motorised Stage for laser

The problem I want to be able to move the direction a laser is pointing. This means I need to have motorised rotation of the laser head in the x direction and in the y direction. I am unsure of the ...
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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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### Smooth servo movement for a crawling robot

I made a small crawler robot a little while ago that had two legs with two degrees of freedom each, so 4 RC servos total. While I was programming the movement of the legs I noticed that they moved ...
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### What is difference between 2 wheels and 4 wheels and tracked differential mobile base kinematics?

In generally I know that no difference between 2WD and 4WD mobile base control kinematics equations. but is there really difference between two wheels differential mobile base and tracked/...
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### 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 ...
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### State prediction of vehicle with Ackermann steering geometry using Kalman-Filter

I am trying to have a Kalman-Filter (or Extended-KF) give me positions for a small remotely controlled vehicle with an Ackermann steering geometry (moving on a plane surface). The control commands I ...
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### Inverse Kinematics 5DOF - general approach - Wrong solution MATLAB

Can anyone name a good source for a general approach (cookbook-like) for the inverse kinematics regarding a 5-DOF? The paper by De Xu et al. is aiming for a general approach, but it doesn't work for ...
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### From a linear force actuator that spans multiple links and joints to the equivalent motor torque

I am programming/using a rigid body joint-space dynamics solver for robots in which I want to implement linear force actuators between links with their equivalent torque sources that are 'spanned' by ...
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### Understanding the Robot Jacobian

Although I have an understanding of what Jacobians are in general and how to calculate Jacobians, I fail to understand how the idea of Jacobian came for use in kinematics and why they are used for ...
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I am trying to simulate and implement the controller of the paper Geometric Tracking Control of a Quadrotor UAV on SE(3). To do this I need to first implement the dynamics of the quadrotor. According ...
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### 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 ...