# Questions tagged [linear-motion]

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### How do linear guides work?

I am new to the office and I wanted to ask about linear guides like shown in the picture: (source: https://www.nskeurope.de/de/linear-motion-control/products/linear-guides.html) Are the carriages able ...
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### Cam for linear actuator from a DC motor

I have a DC motor with known characteristics like torque, speed, etc... The actuator (in green) is like a piston and I know it must be operated as follow: with a force > 60 N the full stroke is 5 ...
• 101
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### Differential Drive Kinematic Constraint Determination

I'm working through a paper to better understand Differential Drive Mobile robots and I'm a bit stuck(fairly early in the paper) on how one of the constraints is derived. The paper is here, https://...
15 views

### What is the physical and mathematical meaning of nonsymmetric mass, damping and stiffness matrix of a linear fluid-solid interaction modeling problem?

Suppose the problem of the subsonic flow over a simply-supported rectangular plate as bellow. According to the assumptions of incompressible, inviscid and irrotational flow, and using perturbation ...
23 views

### To design the system of a rectangular small shaft moving in and out in a completely mechanical way without remote control

In my setup , I have designed a system in which a body will rotate and execute rectilinear motion down the screw along its thread . upon reaching the bottom most point I want to make a system in which ...
34 views

### Design of a linear actuator that is only 5 mm wide

I have to design a linear actuator with a maximum movement of 3 cm back and forth and a maximum force of 5 N. The only constraint I have is that it can only be 5 mm wide. There's no real constraint ...
88 views

### Spring and damper in series, equation of motion

For the motion in fig 4.1 (a), please check the description of this system in the images above, everything should be there. I get it, assuming the positive direction is downward, the spring tension is ...
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1 vote
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### how are larger leadscrews (14mm diameter and up) fixed in place?

So looking at 12mm lead screws and below, it seems like a common method for fixing them in place is to use pillow blocks. The pillow block has set screws which clamp onto the lead screw, and you're ...
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### I'm trying to understand an equation from a motor simulation $\dot w_i (u_ i ​ ,w_i,l _i ​ , \dot l _ i ​ )$

I have a simulated motor and I'm not understanding the math to control it. This is the equation for the force of the motor, also called an 'actuator'. $\dot w_i (u_ i ​ ,w_i,l _i ​ , \dot l _ i ​ )$ w ...
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1 vote
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### Is there such a thing as a double roller/bearing? Two rollers/bearings that share one axis, but can roll independently. [linear/pivot]

I'm looking for two track rollers or bearings that share an axis, but can roll independently of each other. Ideally, they are compact as well ($\leq 1 \text{ in}.$ diameter) and can handle a moderate ...
• 111
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### Retractable linear mechanism with a retractable drive for servo control

I am considering a mechanical system that is able to retract and extend via servo control but with the drive mechanism being retractable itself. Doing so I will be able to have a multiplied retracting ...
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### Help with design of linear actuator

I am working on an automated gate positioner for a drill press. This gate will move back and forth by a set distance so lining up the drill press is automatic. I have tested with the Z axis of a cheap ...
57 views

### How do I calculate the total force required for a linear actuator? [closed]

How do I calculate the total forcerequired for a linear actuator? The image enclosed shows a series of door panels, each with a cam that i would like to connect to a linear actuator on the right hand ...
20 views

### Euler angles from angular velocity pseudovector

According to wikipedia page https://en.wikipedia.org/wiki/Angular_velocity Euler proved that the projections of the angular velocity pseudovector on each of these three axes is the derivative of its ...
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### Motor Power for vertical lift in linear slide mechanism

I want to pull up and down 10 kg metal cylinder at 7 inch vertically by using linear slide mechanism in 1 second. What should be the motor rpm, gear type, torque, watt etc? Otherwise how to calculate ...
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1 vote
451 views

### Ideas for mechanism for quick reciprocating motion - a 'truly' mechanical switch

I need a mechanism to switch the vertical position of an assembly in as square a profile as possible - i.e. a normal crank mechanism produces a sine wave profile, to explain myself better. I've seen ...
91 views

### Raise/Lower 350lb Sawmill Head 12v Motor Specs

I am new to this site and have a problem to solve in an area that I’m pretty lost in. I can usually figure stuff out with the help of the internet and some digging but not getting real traction so ...
28 views

### Linear solenoid mount

I have a linear solenoid with a tapped M3 hole at the end of the plunger, like this: I need to connect this plunger to a lever, so I want to add a mount which has a connection something like this: ...
1 vote
54 views

### Linear motion with triangle profile

I am looking for a way to generate a linear motion with a triangle motion profile for my hobby project. The travel distance should be 6cm (so 12 cm for round-trip) with constant speed 1.2 m/s or ...
1 vote
93 views

### 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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### 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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### 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 ...
• 411
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### 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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1 vote
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### 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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1 vote
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### 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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### 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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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/...
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### 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 ...
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1 vote
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### 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 ...
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### 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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### 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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1 vote
59 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 ...
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### 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 $m$ ...
1 vote
59 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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1 vote
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### 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 ...
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### 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 ...
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### 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 ...
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325 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 ...
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### 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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1 vote
638 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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1 vote
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### 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 ...
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1 vote
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### 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 vote
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### 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 ...
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### 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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### 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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### 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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### 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 ...
1 vote
423 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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