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Questions tagged [robotics]

137 questions
18
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5 answers

Effective ways to drive a single shaft with multiple motors?

To head off the "why not use a bigger motor" question, I'm a high school mentor for an FTC (First Tech Challenge) robotics team, with a bit of a soft mechanical / hardware background. They're somewhat limited in what they're allowed to use, motors…
trycatch
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Knowing how many times the rear wheels have rotated, and the angle of the front wheels at every time interval, how do I find the location of a car?

I'm making a robot for the Sparkfun AVC. I was curious if I could use only the knowledge about How the car is being steered at every time interval, How many times the wheels have rotated, to get a general sense of where the car is. I would use…
Daniel Sims
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1 answer

Holonomic constraint forces using Lagrange multipliers

Consider a multibody robotic system with Lagrangian $$ L =\frac{1}{2} \dot{q}^{T}M\dot{q} - V $$ and equations of motion of the form $$M(q)\ddot{q}+C(q,\dot{q})\dot{q}+A^{T}(q)\lambda+N(q)=0 $$ where $N=\frac{\partial V(q)}{\partial q}$ and…
Bourbaki
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4
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1 answer

4 Gears in a Circular Pattern - Calculating the Proper Distances for Meshing

I have recently been working on a gearbox for a robot. I have this pattern of 4 gears with each gear connected to its 2 neighbors. It looks like this: You will probably notice something though. Large gear on the right and the small one in the…
Ben L
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4
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2 answers

Are precision pneumatics possible?

I've seen some of the robotics competitions use pneumatic actuators for brute force actions ( like a hammer or lift ), but nothing precise. Is it possible to use pneumatics in a more precise scenario?, I'm assuming this is how pneumatic robotic arms…
user379468
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3
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3 answers

How do robots maintain stability?

I've been watching a clip of a robot dragging a heavy load behind it. I am wondering, in a fairly high level, how does the robot maintain its balance? For example, I know that with a Segway, there is a gyroscope which senses in which direction the…
Karnivaurus
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1 answer

Which joint is providing the force to a bipedal robot to move the body forward?

This is related to construction of a bipedal robot. I have a doubt regarding the stages involved in walking of a biped. In the one leg support phase, when the body moves in a circular path about one leg, who is providing the force? How can the joint…
horaceZettai
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Problem in the inverse kinematic model of a car like vehicle?

I'm a electrical engineering student and i am building a simulation of a car like vehicle . As I understand it: The input for the forward kinematic model are the control variables and the output is the position of the vehicle The input for the…
zed_eln
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3
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1 answer

Power a microcontroler with a motorcontroller?

I have a motor controller that operates at 10-50V and draws 5A controlling a 3V motor that draws less than 1A. I had a an idea where I want to try to use a microcontroller to control this set up. The motor controller has an auxiliary 5V output that…
gunter
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3
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1 answer

Units for rotational impedance

I'm trying to use the mechanical impedance analogy to describe a spring mass damper system as an electrical circuit. Mechanical Impedances for linear motion are $$ Z_{lin}(s) = \frac{F(s)}{\dot X(s)} = Ms + B + \frac{K}{s} $$ where M has units of…
wyverniv
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Equation of motion for 2-link arm

I have the following robot arm: Now how do I obtain the equation of motion: $$ M \ddot\theta + \vec{b} + \vec{g} = \vec{\tau} $$ I am familiar with forces, torque, velocity and so on. I know that this equation follows from force and torque…
jkbx
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3
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3 answers

How to design a vacuum climbing robot

I'm trying to design a mobile robot which has to climb over flat 60° inclined wet glass surfaces. I was thinking to use a large vacuum system composed by a large fan connected to a brushless motor. By looking on google, I found this photo: As it is…
Marcus Barnet
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3
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2 answers

How to calculate rotations from displacements?

I'm trying to develop a finite conical shell element with six dof at each node. I want to express the rotations $\phi$, $\theta$ and $\psi$ in terms of the displacements $u$, $v$ and $w$. The displacements are functions of $x$ and $y$. Using the…
Damingow
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2
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2 answers

Torque Problems vs Motor Problem?

I want to preface this by saying I am software engineer so each part of this robot build has been a lesson on its own. From welding, to CAD design, pillow block bearings, etc, etc.... I am working on a DIY Rover using the following components: 4…
Sam Hammamy
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2
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Relationship between the infinity norm of estimation error and the trace of estimation error covariance matrix in Kalman filter

I am working on designing an interconnected distributed control system. In this system, I need to use Kalman filter because the measurements are noisy. I have two questions: 1 - What is the relationship between the infinity norm estimation error and…
Spring Breeze
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