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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What motor do I need to mimic the opening mechanism of flower petals? [closed]

I am completely inexperienced in any technical areas. However, I need a small motor for a larger art project and was hoping that someone here might be able to help me. I would like to build a flower ...
1 vote
1 answer
21 views

Trying to rotate an axle that is oscillating along its axis of symmetry

I have an axle that is currently oscillating along its axis of symmetry, and I want to now rotate it around its axis of symmetry as well using a motor. I realize this is a pretty tough problem and may ...
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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 ...
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 ...
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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 ...
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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 & ...
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1 answer
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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 ...
1 vote
1 answer
50 views

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 ...
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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 ...
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3 answers
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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 ...
1 vote
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Mechanism to oscillate a human leg? [closed]

I'm working on creating a robotic device capable of oscillating an adult human leg using the knee as pivot, being able to constrain the amplitude of oscillation by controlling the mechanism with a ...
2 votes
0 answers
79 views

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 ...
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Heavy omnidirectional platform suspension

I'm planning to build an omnidirectional platform that will support about 180kg robotic arm. The platform will be equipped in meccanum wheels. I would like to have some kind of suspension to avoid ...
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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 ...
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1 answer
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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 ...
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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 ...
1 vote
1 answer
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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, ...
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2 answers
41 views

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 ...
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1 answer
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I need the scheme of iRobot Create 2 [closed]

I've tried to drill a number of holes in my iRobot. I've missed one of them and I need the electronic scheme of iRobot Create 2 for trying to restore this input of the data cable. Can you help me with ...
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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 ...
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1 answer
141 views

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 ...
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1 answer
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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{\...
2 votes
2 answers
236 views

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?
5 votes
2 answers
2k views

How does the Makeblock threaded slot work?

I've been looking into a Makeblock robotics kit but have found no information on the web that comes from end-users, and one of the main advertised features is not clear to me: The slot threads shown ...
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67 views

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 ...
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228 views

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 ...
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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 ...
1 vote
2 answers
1k views

Different methods to determine DOF: Chebychev-Kutzbach-Grubler method vs. Screw method

I'm familiar with Chebychev-Kutzbach-Grubler method to determine degree of freedom of a robot arm. But it seems this method fails to calculate the mobility of some parallel robots, as explained here. ...
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 ...
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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 ...
1 vote
2 answers
304 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?
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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 ...
1 vote
1 answer
53 views

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 ...
2 votes
1 answer
150 views

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 ...
5 votes
1 answer
4k views

12V compressor and air pressure control

I am trying to make a simple robot with few functionality for someone, one of these functionality is inflating a balloon inside the robot, I know how to control a compressor using Arduino but the ...
8 votes
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9k views

How do I motorize the elbow socket and other joints in a powered exo-skeleton?

How would you motorize the joints in an Iron Man suit? You need something fairly shallow, I would think, probably dual servos sitting on either side of an elbow or knee joint or either side of your ...
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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 ...
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50 views

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 ...
1 vote
1 answer
771 views

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 ...
2 votes
2 answers
356 views

How to seal a threaded rod so I won't lose oil?

I have an M5 threaded rod that penetrates a box. Outside it is driven by a motor and it rotates a part inside the box. The box is sealed and I would like to seal the area around the rod as well. I ...
0 votes
1 answer
283 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 ...
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1 answer
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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 ...
1 vote
2 answers
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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. ...
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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 ...
1 vote
1 answer
270 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 ...
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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 ...
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1 answer
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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?
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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 ...
1 vote
1 answer
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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. ...
3 votes
1 answer
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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 ...