Questions tagged [linear-motion]
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46
questions
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Is a pneumatic cylinder in general a linear or rotary actuator?
I've just begun to learn pneumatics and I'm really confused where the pneumatic cylinder falls under in the categorization of what kind of mechanical motion it is suppose to produce. I've seen one ...
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2answers
56 views
How do I calculate the ideal travel distance of the ball screw per revolution of the stepper or per step for the following hardware?
Question How do I calculate the ideal travel distance of the ball screw per revolution of the stepper / per step for the following hardware (I believe this is called the lead)?
Background I have a pre-...
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1answer
51 views
If aboard a train being driven along a track by centripetal force, would it feel like you were on a regular straight track?
Question: If aboard a train being driven along a track by centripetal force, would it feel the same as if you were on a regular straight track?
I hope this isn't subjective, I think there is a right ...
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0answers
35 views
How much force can an acme lead screw handle?
I have a stepper motor that claims 425 oz*inches torque. I want the lead screw to span 2' supported on both sides. I'm trying to decide what diameter lead screw is strong enough to not be damaged by ...
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3answers
58 views
In circular motion , why do we say this is centripetal acceleration
Let us say a particle is moving in a circle with Uniform circular motion .
Then , if I take an equation like this .
$\theta$ = S(Arc length or Total distance covered ) / Radius of circle *( time ...
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2answers
36 views
Did not understand this regarding angular velocity
It says $V\sin \alpha$ (component of velocity perpendicular to OP) is the cause of angular displacement. How is it?
if only $V\cos \alpha$ existed, we need not turn over head to always to look at a ...
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1answer
8 views
Calculating Gearing Ratio from Constrained Rotational Linear Arc and Horizontally Opposed Rotation
I'm 3D printing an aircraft throttle unit as a POC and am trying to calculate the gearing ratios that are required in order transfer the full range of linear motion into a directionally opposed sensor ...
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1answer
49 views
Linear Motion Stage with Offset Loading Problem
I'm currently developing a linear motion system which will have to withstand a large offset load (see image below). There will be two rails, each with a carriage on, which will be connected by a beam/...
2
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1answer
46 views
Single linear actuator lifting mechanism
I have inherited a DIY build and I have some doubts about its design. Have a look at the following diagram:
1 is the linear actuator. It's quite beefy 2000 lbs 12" stroke. It is installed in an ...
1
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1answer
44 views
CNC side linear rails
I've been wondering why most (hobby) CNC machines have two actuated linear rails like this:
Besides the extra force for moving the spindle, is there a need for both rails to be actuated? Could the ...
4
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3answers
198 views
Off-centre actuation
I'm trying to lift a platform with several guides using a linear actuator, but off the centre as follows:
The load on the platform will be around 100kg, which is just within the linear actuator's ...
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2answers
292 views
Lifting a cabinet using actuators or scissor lift
Disclaimer: I am not an engineer - just a DIY guy looking for some advice or help please, so please forgive me if I use incorrect terminology :)
I am building a cabinet that has a hidden inner cabinet ...
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0answers
38 views
How can you convert 180 rotation into two separate motions?
I have a small servo that can rotate 180 degrees. I would like to get two different connected parts to move at different times, one part moving while the servo is between 0-90 degrees, the other part ...
2
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3answers
92 views
Difference between Linear Force and Force about an Axis
I am confused between How forces work when applied in singular linear direction vs Force Applied to a continuous mass about an axis(example to rotate it).
Example 1:
Consider an object of mass $m$ ...
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1answer
35 views
Linear actuator with low vibration and low noise
Which kinds of linear actuators offer the lowest levels of noise and vibration?
I am looking for an actuator with these properties that can push a load vertically on the cm scale. Velocity, accuracy ...
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1answer
30 views
Can I use more than 2 linear guides to support a linear stage?
I am designing a home CNC mill for machining nonferrous metals. I plan to use linear guides to support either a Y-axis table or the 2 legs of a Y-axis moving gantry.
Linear guides are used to ...
2
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1answer
25 views
Linear guide ball bearings
I'm planning to drive a small linear guide (4cm long) with a servo in a setup like this:
I wonder if the ball bearings inside would sustain too much stress due to the vertical forces exerted by the ...
0
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3answers
86 views
What causes opposite motion in Newtons third law. Or is the mottion matter independent?
For every action, there is an equal and opposite reaction. Sample case me doing a push up I force myself to move up by pushing against a rigid body ( the floor ).
There goes I can not push myself ...
4
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2answers
117 views
Linear actuator behind lifting boom
This is a follow-up on my previous question here:
Sizing a motor for a floor jack-like mechanism
The floor jack setup is clearly inefficient when it comes to electric actuators. Something similar to ...
2
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3answers
50 views
Design Input: Rotary motion to Linear motion, What system should I choose?
I am posting this here because of the multidisciplinary knowledge needed to tackle this issue.
Problem: I have to make an electromechanical device that is required to have controllable (downward) ...
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2answers
267 views
Stopping force on wire rope from a falling object attached to it
Okay, bit of a weird one. Imagine an object of known mass in free fall, tethered by a wire rope to an infinitely stiff sky hook. When that wire rope eventually tightens, what will be the stopping ...
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0answers
68 views
Is it possible to have the load cell signal as feedback to the servo drive of the servo motor?
In my project, I have to control the linear motion in one of the two modes. It will be either in position control or load control.
for the displacement control, The servo motor takes the quadrature ...
1
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1answer
27 views
How to constrain stepper motor inside case?
I have a stepper motor linear actuator assembly like this for example, but the stepper shaft seems able to move axially back and forth - hence when I change direction it has to do a few rotations, ...
1
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1answer
41 views
Help with linear rod drill press like design/materials
I am putting together a basic machine for “pad printing” extremely small and precise parts. The design is very much the same as most homemade drill presses and consists of linear rods, flanged ...
2
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1answer
101 views
How to solve this linear motion problem?
Context:
I have a lead screw rod, nut and a pulley aligned vertically. The nut is attached on top of the pulley so their respective bores are aligned and the rod is arranged so that it is threaded ...
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2answers
102 views
How to debunk this “Perpetual Motion Machine?”
Here is video of a purported "perpetual motion machine."
How do you explain its behavior?
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1answer
72 views
Ceiling Mounted Camera Slider with Pan
I am looking for feedback on my camera rig design. I am going to run a track along the ceiling of my studio to move my camera back in forth. I also want the camera to be able to pan, so I want to ...
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0answers
27 views
Using carbon brushes on linear guides
I’m designing a machine which has an actuator on a carriage sliding on two round linear guide shafts. I got an idea of transmitting electricity to the actuator through the shafts. There would be ...
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2answers
328 views
Rotary to linear motion - how to make upside down “hammer” mechanism?
I’m not an engineer, however I think this place is the best one to find an answer to my question.
So my problem is as follows: I need to create a mechanism, preferably driven by a dc motor, that will ...
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0answers
115 views
Equations of motion for a motor supported by a spring resting at the centre of a beam
Assumptions from this:
Sum of forces on the beam to be calculated
Sum of moments on the beam to be calculated
Sum of forces on the motor to be calculated
As:
F=-kx = kθL^2
Equations of Motion
...
1
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1answer
125 views
What lead screw to use for specific torque and speed requirements?
The setup: I'm trying to mount a leadscrew powered by this motor Tetrix Max Torquendado Motor on a 40ish pound robot, in order to lift it 4" off the ground. I already have the linear motion, latching ...
1
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1answer
72 views
Sharing load between linear actuators
I'm building a motorized standing desk and am trying to calculate what linear actuators I need. If I have 4 linear actuators (one on each corner) each able to lift 25kg does that mean that the desk ...
2
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1answer
99 views
Dynamics of a rigid body in a system of two linear drives
I've been trying to solve the dynamics of this system for quite a while, but cannot seem to get the right answer. I've tried solving it with Lagrangian method but I am not so confident with the ...
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0answers
47 views
Linear actuator calculations
I'm building a motorized standing desk and am looking into what to use for the linear actuators. I'm targeting a stroke of 450mm and a lifting force of 100kg. I found some Linear Actuator on ebay that ...
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0answers
113 views
Shaft which can independently rotate and translate axially
I would like to mount a sensor onto a shaft which can be translated axially as well rotated independently. This arrangement permits me to capture a 360 deg scan and then translate the shaft axially to ...
3
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2answers
3k views
Converting Linear Motion into rotary motion
I'm looking at designing something using the same mechanism used in this pepper grinder. As far as my knowledge goes, it is converting vertical Linear motion (the push button) into horizontal rotary ...
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0answers
33 views
Steering with a push / pull action. Is there an easier way?
Linked to my previous question Push / Pull Steering on an axle, I now have time and space to work on the full scale project. I have noticed an issue with the answer that is there, and that is, the ...
1
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1answer
82 views
Need to produce vibration amplitude of 200 um (approx) at natural (resonant) frequency, can be any frequency between 100 to 150 Hz
In order to conduct study, I need to produce controlled vibrations with amplitude (maximum) approx 200 um (micro) at frequency between (100-150) Hz. Vibration amplitude must be controlled with input ...
3
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1answer
324 views
Quick return mechanism for spring-loaded screw
Looking for a way to convert rotary motion to linear, but it should take less energy to get back to initial position than when going from initial position to the end position.
Specifically, a screw ...
0
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1answer
66 views
Analytic expressions of the kinetic and potential energy [closed]
A homogeneous rigid circular disc (radius R, mass ms, center point S) rolls without a slip on a plain with a small angle of inclination alpha against the horizontal. A point mass MG is fixed on the ...
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1answer
2k views
Linear actuator on a scissor lifting table
I am designing a scissor lifting table and I have an issue with the linear actuator. This table should be lifting 100 kg. I studied the problem in two ways : a static study and a power study. My ...
0
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1answer
41 views
How can I calculate headphone driver excursion?
I'm a headphone enthusiast, and once I tried to open up my headphones to see how much they move when I play my music.
However, I was really surprised to see that the sounds that I could "feel" ...
0
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1answer
194 views
Push / Pull Steering on an axle
I have a base with 4 wheels, the rear axle is a motor which drives the base forward or backwards, this contains a diff, so there's no problem there.
The front axle is a steering axle like that in a ...
0
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2answers
66 views
What type of supports exists for ballscrews or leadscews?
For Linear actuators, a common mechanism is to use ballscrews with ballnuts.
The ballscrew is supported at the two sides by a set of bearings which permit the rotation of the screw while keeping the ...
3
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2answers
186 views
Simple mass spring damping system sizing K, and C factors
I have come across a problem, which has troubled me for some time now. What needs to be done is the following:
A mass on a rod 0.6m (mass less) has a mass of 1 kg attached at the end of it. The rod ...
1
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0answers
24 views
Linear Guidance law into X-Y axis
Im currently writing a model for a guidance law named Maintaining Guidance law.
The law looks as following: $$ a_{M} = [K_1,K_2]*[\dot{\lambda_T} ,\dot{\lambda_D}]'$$
Since im using a linear model I ...
