Questions tagged [mechanism]

A mechanism is a device designed to transform input forces and movement into a desired set of output forces and the movement.

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Screw theory for kinematics/dynamics of mechanisms

Is screw theory commonly used for general kinematics/dynamics of mechanisms (not just robotics)? I'd be interested in anything that covers the types of mechanisms you would find in a typical ...
Molecular Lionel's user avatar
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DOF computation

I am new to self-learning robotics and while browsing I found quanser hexapod that has 6 degrees of freedom (https://www.quanser.com/products/hexapod/). I used the Grubler's formula in Lynch & ...
Jordan G's user avatar
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Light weight one axis hinge name/recommendation

I'm attempting to build a crow that can stay upright even when its perch tilts. For that I need to have some single axis hinges (not u-joints). I'm using 3mm rod for my internal supports and am ...
Oldmicah's user avatar
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How to find coefficient of friction that will maximize torque?

When using DC motors with a drive wheel (aka "direct drive") to propel a vehicle (e.g. an RC car), force and torque play a role in how efficiently that motor's power is transferred into ...
tniles's user avatar
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How to maximize top speed potential for a given motor? [closed]

I have an engineering background however I am new to motors. I am looking to understand what the options exist for maximizing the top speed a motor can produce (say for an RC vehicle) without simply ...
tniles's user avatar
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Doubt regarding publishing of robot in a journal or to be applicable for a presentation

i was just curious about publishing an abstract or stuff like that about a robot I've made all by myself . Do i really need to make a working model of it or 3d solid works or cad will be enough ? . I ...
Sergeant Afanasiev's user avatar
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Floppy fish mechanism design

I've bought a floppy fish toy (crab version) for my kid. The toy looks like: Unfortunately, the toy mechanism inside jams when grabbed and the battery lasts for a short time: I tried to do my own ...
SKJQ's user avatar
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What geared mechanisms can convert various weak stepper motors drive inputs into a higher torque output?

I'm interested in making an arduino robotic arm for something that need precision and/or torque (like CNC), but first, I'm exploring/searching what I would need and how much it would cost. What I ...
Fulano's user avatar
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Why in forward bending knee orientation in quadruped legged robot require less torque in knee joint?

I'm trying to find answer in terms of physics explanation, why knee joint torque requirement is less in the forward bending leg orientation of a quadruped legged robot. I'm referring this article, in ...
Dibyasankha Kundu's user avatar
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Communication error

My Robot arm and controller battery got ablated it showed H1600 mechanism error.. did ram reset of the controller but controller not seeing robot arm. it is RV-2FB-D1-SM15 Robot arm and CR750 D ...
muhammad aminu's user avatar
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What thread to use for a load-bearing telescoping lift [closed]

I'm trying to find a thread that has good fatigue resistance and strength for a telescoping lift. The lift will lift a weight of around 2-3 kg. I do not intend to spool it as I read that thread with ...
Mushroom1's user avatar
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What is meant by the phrase "movement positional jitter"?

I was searching online for the meaning of this statement but the closest I came across is that jitter here refers to some sort of "deviation". Therefore, if we say that the movement ...
CynthiaZ1998's user avatar
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Choose the structure of the dynamic model for the generalized equations of motion of the robot

I ask the robotics specialists for help as I am a little confused. I have two subsystems which are shown in the picture below: One of them is a system of stable and controlled differential equations ...
dtn's user avatar
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Jacobian for transformation of rotation angles

It is known that with the help of the Jacobi matrix it is possible to transform the angular velocities of the drive links $\boldsymbol{\omega}$ into the angular velocity of the platform $\boldsymbol{\...
dtn's user avatar
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Spherical Parallel Manipulator Lagrangian problem

I faced a very serious problem and I urgently need the help of specialists in robotics, mechanics, physics and mathematics. I am trying to derive equations of motion from the Lagrangian of a spherical ...
dtn's user avatar
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How to choose a servo motor for solar tracking mechanism?

I design a solar tracking mechanisim. You can see the very undetailed representation in the pic. For choosing a servo motor how can I calculate the torque etc?
HollyPolly's user avatar
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What should be my spray handle-servo interface for pull mechanism? [closed]

I am an electronics engineering student who recently started working on Arduino. As part of my efforts to wake up on time, I decided that I should make an automatic water spray alarm clock. I have all ...
Prasanjit Rath's user avatar
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Why isn’t my shaft moving? [duplicate]

When I put my shaft through the vehicle body (small robot) and have the motor attached to it through two rotating gears, the shaft isn’t rotating? I think it’s due to how the hole diameter is the same ...
Ralph Faure's user avatar
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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 ...
user3134909's user avatar
1 vote
2 answers
290 views

Why do we say a robotic arm have 2 dof even though the two joints rotates along the same axis?

Why do we say a robotic arm has 2 degrees of freedom even though the two joints rotate along the same axis? Why isn't it called a 1 dof robot?
ForgottenTale's user avatar
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What is the most accurate method to calculate Torque of 5 DOF Robotic arm

I am working for development of a 5 DOF Robotic arm , and I am confused in the Torque calculation This is a 5 Axis revolute Joints Robotic arm , where Motor for 1st axis will rotate the turning table ...
Muzammil Ibrahim's user avatar
1 vote
1 answer
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Motorised steering without shock absorber?

I was looking up on the Curiosity Mars Rover and noticed that the steering appears to be driven by a (geared) stepper: I presume the drive contains a worm gear to reduce power consumption of the ...
John M.'s user avatar
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Simulation of Robotic arm

I want to simulate my 5 DOF robotic arm, in such a way that the calculated Torque and mass values of each joints (Servos) defined to be tested that are they capable of physically bear all the weight ...
Muzammil Ibrahim's user avatar
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How to design a robot chassis so as to avoid bending issues?

I'm good on the programming, control systems and electronics aspect of robotics, but need help with a problem with mechanical design. How do I avoid bending of my chassis due to weight? It is a 2 ...
jash's user avatar
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How to create a jumping mechanism for a small robotic car?

I have to create a jumping mechanism for a small robotic car and was thinking about using a spring mechanism to do so. However, due to dimensions (16cmx8cm) and mass constraints (below 200g) I cannot ...
Alexandre Berkovic's user avatar
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What sort of robot would one use to tie precise knots in a string?

I need many knots tied repetitively and consistently in a string. I have been trying to make something which ties knots for me in a consistent manner. I've got a project which requires a few hundred ...
tuskiomi's user avatar
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Rotating a lever with a small servo

I'm trying to rotate a lever link to gently "offload" a load using a servo. Here's a drawing: Here, the red is a lever, yellow pivot and black is the load. To offload, the lever needs to be turned 90 ...
John M.'s user avatar
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270 views

Wall-E Legs mechanism

I was trying to understand the mechanism of Wall-E's Legs from the Wall-E 3D animation movie of Pixar Animation Studios, how he is able to move up and down and move the tracks on all directions. Can ...
Iron Fist's user avatar
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Why are the angular velocities of concentrated masses in Lagrangian independent?

There is an ordinary linear three-mass system. If we write its Lagrangian, we get the following equation. where $W_k$ and $W_n$ - kinetic and potential energy. To find the moment of rotation of the ...
dtn's user avatar
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Dynamic models of parallel robots in the form of multi-mass systems with stiffness coefficients

I want to develop a dynamic model of a parallel robot for control tasks. It is known that equations of motion based on Lagrange equations can be transformed into a state space and use such a model. ...
dtn's user avatar
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How to make small quantities of gears

For a hobby project, I'm designing a clock with a single hand that makes one revolution per year. Using really helpful sites like https://geargenerator.com/, I have the gear ratios and dimensions ...
Ken Williams's user avatar
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1 answer
261 views

How does this end effector work?

I've seen this linear actuator end effector on a few industrial SCARA 'bots but I am having trouble visualizing how it works internally: It looks like a type of lead screw, but the nut must spin ...
kp122's user avatar
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How to use thrust bearing with shaft?

I know how to use radial bearings, e.g. ball bearings with shaft. But no matter how much I googled I didn't find any proper clear way to use thrust/axial bearing with shaft. I downloaded the thrust ...
user24101's user avatar
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1 answer
1k views

Selection of motor and Calculating the torque for 6DOF robot Arm

I am trying to select the motor for a robot arm with six degrees of the freedom robot arm. What should I do to select the motors and which type of motor I should select?
Muhammad Khird Added's user avatar
1 vote
1 answer
211 views

Controlling Actuated Robot Hand in Underactuated Manner

We have an allegro hand in our robot, and it is in actuated behavior. In other words, each joint is controlled one or more than one actuator, that is motor. There are 3 actuators for each finger, ...
Goktug's user avatar
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1 answer
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What should i do to rebuild robot salto from Berkeley uni as a mechanical engineering undergrad?

What are the main components of robot salto? What are the necessary skills and knowledges to reproduce it? Also as you can see, i am a mecheng and i want to reproduce this robot as finishing project ...
user31416's user avatar
1 vote
1 answer
72 views

Robot mechanism parts names

I'm working on my first "robotic" project that involves a square platform that should drop one of the four sides at a time. ...
KeepLearning's user avatar
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1 answer
51 views

Design a robot that can apply hot glue to paper

I need to automate a process that involves applying hot glue to paper. I own a standard handheld hot glue gun, like this one: Sticks of room-temperature glue are fed in the right side. Pulling the ...
CreatedByBrett's user avatar
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1 answer
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How should I create a Pangolin (Armadillo) structure?

I am new to this forum. I want to create a mechanical structure as depicted in the image A pangolin bag. And further wouls like to automate the closing and opening of the bag. But I am facing issues ...
Hrithik Baishakhiya's user avatar
3 votes
1 answer
84 views

High power jumping mechanism in small robots

I recently saw this video on YouTube featuring a jumping robot: 5 Fastest Robots In The World I was curious how this is accomplished mechanically? Do they wind a strong spring or use some sort of air ...
FutureCake's user avatar
2 votes
2 answers
1k views

How do I calculate the direction robot is facing, pose from velocity and yaw rate?

I have a simple car robot with four wheels moving relatively slowly (5~10 mph). The robot has a velocity magnitude and yaw rate sensor and the sensor samples about every 0.1 seconds. I want to map the ...
John Doenut's user avatar
2 votes
1 answer
1k views

How can I attach an arm to a double-flat drive stepper motor?

This is my first robotics experience, outside of one class 10 years ago. I've been Googling this question for about an hour but I can't find an answer! I'm using a ROHS Step Motor 28BYJ-48 (with an ...
CreatedByBrett's user avatar
0 votes
1 answer
396 views

Rotating two things on the same axis

I'm working on a project where I want two separate shafts to be in the same place. Think of it like a clock where the hour and minute hands move independently. Also like a clock, I want the motors and ...
hjfreyer's user avatar
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1 answer
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What is the front mechanism of this robot's track called?

What is the mechanism on the front of the tracks of this robot called? They are also tracks, but they are able to be moved by the operator, and they are able to function as tracks. I've only seen ...
YetAnotherRandomUser's user avatar
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1 answer
35 views

Pnumatic sulinoid with multiple outputs

I can't figure out what solenoid I would use. Everything I search for comes up with cylinders. Not sure if it's even a sulinoid that I need. I'd like to have 8 hoses connected to a compressor. I'd ...
SolidCloudinc's user avatar
1 vote
1 answer
109 views

Can somebody explain how these forward kinematics matrix equations were formulaed?

Here's the link to the entire answer: Designing a 5 bar linkage robot: Plot Clock
Aman Agarwal's user avatar
0 votes
1 answer
159 views

DC geared motors or leadscrew and motor for joints

I'm trying to build a quadruped robot. I studied dynamics and to get an idea, I read and watched papers and videos related to robots like ALof and StarlETH and some more. But since this is my first ...
KalanaRatnayake's user avatar
-1 votes
1 answer
60 views

How to transfer motion between these two parts?

I'm trying to model this arm and I'm having a problem knowing what way could I use to make the red part always parallel to the surface of the table
Abeer's user avatar
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1 vote
1 answer
155 views

How to turn direction of 4 planar wheels into up/down motion?

For the head in a 2D plotter I have 4 gears in an X configuration in the same plane. The gears are driven by belts from the outside in different combinations. The top and bottom gear can be turned in ...
Goswin von Brederlow's user avatar
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1 answer
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Sliding system basic question

I have a basic question. Imagine a plate, with a hole drilled in each corner. Imagine 4 shafts in these 4 holes,attached to another plate. Intuition tells me that it would take considerable effort ...
chrisvp's user avatar