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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8
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3answers
7k 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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3answers
176 views

Education sources for robot building?

I teach FTC robotics to high school students, and while I'm a proficient programmer and can teach them coding fairly well, my mechanical skills are a bit soft. I'm looking for good sources for myself ...
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2answers
753 views

SCARA Arm Lead Screw Choices

I'm thinking about building a SCARA Arm to lift moderate loads(5lbs) with a high degree of accuracy. I want a relatively quick and inexpensive Z axis gantry, and I was thinking about using a lead ...
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4answers
344 views

Can you have a career in robotics if you hate mechanics? [closed]

I'm a first year electronics engineering student. I love almost all the aspects of robotics - the electronics, algorithms, control theory etc. I can't stand the mechanical aspect of robotics though. ...
5
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2answers
164 views

Plastic shaft supports

I would like to prevent a shaft from being pulled through it's bearings - that is, press a plastic ring around it on either side. What are these rings called? They're not bearings or hubs. And where ...
5
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2answers
1k views

Building a non rotating persistence of vision device

I'm looking for a way to create a non-rotating persistence of vision device. I have all the electronics set up but I'm stumped with the mechanical design. I tried these two designs: But these didn't ...
5
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1answer
1k 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 ...
5
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1answer
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 ...
5
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4answers
157 views

Why linkage-based haptic devices are much more common than cable (tension)-based ones?

According not only to this link, but in my humble opinion to common sense as well, cable-based haptic devices have got lower inertia and are less complicated mechanically. I also believe that ...
5
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1answer
486 views

Gears modeling in Google SketchUp and SketchyPhisics

I'm trying to make differential in Google SketchUp using this tutorial http://support.ponoko.com/entries/21249896-Gears-and-Joints-with-SketchUp-Sketchy-Physics for gears modeling. But I have problem: ...
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3answers
631 views

How can this mobile robot rotate so perfectly?

Please have a look at this youtube video. When this mobile robot operates, the rack (which is said to weight up to 450 kg) can have its Center Of Mass (COM) distributed at any location. For example, ...
4
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1answer
3k views

How to measure and dispense a finite amount of powder or liquid

I've been watching too much How It's Made, and I've been wondering how they build devices that spray/inject/dispense a finite amount of liquid (to within some amount of error). I wanted to try this ...
4
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1answer
99 views

Attaching a M5 screw shaft to a cog wheel

Does anyone know of a good (low profile) way to attach the threaded (chamfered) end of a M5 screw shaft to a 30MM (30T 1M) plastic cog wheel? Would it be a good idea to widen the shaft hole and just ...
3
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2answers
674 views

Industrial Robotic Arm

I had the opportunity to work for a factory/company that is in the domain space of production and they want to use a robotic arm for part of the production line. They want basically a robotic arm ...
3
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2answers
1k views

Lifting robotic leg with only one servo

Note before I start: I have not actually put anything together yet, i'm still just planning, so any changes that require a shape change or anything like that are accepted. I'm working on making a ...
3
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1answer
76 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 ...
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3answers
38 views

Fastening sheet steel on nylon

I'm trying to attach a small piece of sheet steel (30mm x 50mm x 1mm) to a small piece of nylon (50mm x 50mm x 4mm). Does anyone know how they could be fastened using small screws ( Any thought ...
3
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1answer
1k views

How does Fliike Smiirl counter mechanism work

First of all please see this video : http://www.youtube.com/watch?v=n0dkn4ZIQVg I think there is ony one stepper motor -or servo- working in the mechanisim. But as you can see each flip counter works ...
3
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1answer
127 views

Once you understand motors, what's the next step? [closed]

I've gone through tutorials on how to build circuits and control dc, stepper, and servo motors. I may not understand everything about them internally, but i have a good basic foundation. Now i'm ...
3
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1answer
84 views

POM gears and metal fittings

I'm looking at this setup: where the POM bevel gears are fitted with some kind of metal (bronze?) tube inside which fits over the shaft. What benefits does this method provide? Is it to allow the ...
3
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3answers
630 views

Atlas Robot Reference

Boston Dynamics keeps making great robots, however, I dont see any papers that they publish. Although now I can find papers on people using the ATLAS robot, I can not find an original paper detailing ...
2
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1answer
115 views

How has the Mars Exploration Rover (MER) has been working for 11 years if it was designed for 90 Sol? [closed]

The Mars Exploration Rover (MER) Opportunity landed on Mars on January 25, 2004. The rover was originally designed for a 90 Sol mission (a Sol, one Martian day, is slightly longer than an Earth day at ...
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1answer
1k views

What is torque bandwidth in actuated joints and how does it affect the control systems?

The rest of my student team and I are in the process of redesigning an exoskeleton and building it based on an existing one. From the papers that we have been reading there are some references to low, ...
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2answers
193 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 ...
2
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1answer
190 views

Reverse lift mechanism

I have made a RC robot from a wheelchair and I'm planning to attach a snow plow. I'm wondering if there is any mechanism that would be able to lift the plow when reversing. I have only 2 channel ...
2
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1answer
186 views

Lawn mower robot (type of cutter)

If not all, but major types of lawn mower robots are rotary mowers. I presume1 that reel mower is more efficient, and is said to leave a better lawn health and cut. So, why industry go to the other ...
2
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1answer
66 views

Is this gear design feasible?

I came up with an idea and am working with a mechanical engineer to design and prototype the idea but I keep sketching out my own ideas in the process and I just came up with this.. I'm quite sure ...
2
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1answer
93 views

What to use as electrovalve?

I want do make following installation (blowing bottle tops as music instrument): ...
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2answers
118 views

What is the Name of the part I'm describing

I'm looking for a part that will do a particular function. It has to be able to move along one axis and tell me the force that is being exerted on it. Kind of how like a piston moves inside an ...
2
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1answer
97 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 ...
2
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2answers
576 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 ...
2
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1answer
4k views

How to link ends of timing belt into loop

When I buy some length of timing belt I don't know how to link ends of timing belt into loop. So far I've found one way to do that (thanks to http://www.lasersaur.com/): http://www.flickr.com/photos/...
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1answer
6k views

What motor to use for reciprocating (reversive) movement [closed]

I want to make a copy of this machine Fisher Price Soothing Motions™ Glider and I'm wondering what motor to use? Simple DC motor with appropriate gearbox (slow rpm) or stepper motor? Here is another ...
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0answers
1k views

How to connect a servo motor and a crank shaft

I have a standard 5v I am using the horn it came with it, I mean this piece: Like the long arm in the middle. Each of its holes are 1mm diameter. Then I have a 3d printed crankshaft I did: Its ...
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2answers
227 views

Beginner question about software for calculations

I'm a complete beginner in robotics with background in programming... I started thinking about a robot project yesterday and want to order some motors to test with. I saw the specs for the motors, ...
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4answers
1k views

Fuses for mechanical systems

** If there's a better stack exchange site for this, let me know--the mechanical engineering one is closed so I'm not sure where else is appropriate ** Do mechanical systems have fuses? In an ...
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1answer
1k views

Good book on mechanisms [closed]

I am working with students (9th & 10th grade) on robotics and wanted to get a good book which covers basic mechanisms. Does anyone have any recommendations. Searching Google or Amazon yields ...
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3answers
64 views

Is this supposed to be a bearing?

I'm looking at the assembly of a tail rotor that should look like this original image I wonder if the "tail output shaft stopper" (circled in red) is meant to be a bearing or just a piece of metal ...
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1answer
56 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. ...
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2answers
906 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. ...
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1answer
113 views

What's the name of a robot manipulator construction with multiple thin arms joined together?

I am seeing on some videos robots picking items and putting them somewhere in order. Here are some examples: https://www.youtube.com/watch?v=wg8YYuLLoM0. https://youtu.be/ggFdvUlp8YU?t=38 How are ...
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2answers
48 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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2answers
62 views

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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1answer
82 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
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1answer
64 views

I need help figuring out what motor is used in this design

I am learning how to make rigs for high speed motion control. Basically, whatever action needs to be executed must be done by a rig that is triggered at an exact moment. In this particular case, I ...
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1answer
738 views

How modular arm joints work [closed]

Hello I'm trying to figure out how modular arm joints are designed and what kind of bearings/shafts are used for a modular-type robotic arm. Take "UR arm" for example. I believe those 'T-shaped pipes' ...
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1answer
49 views

How to distribute tension load on a three footed claw?

Good day! I am helping my little ones 6 and 7 to develop a robot that can pick up and stack cubes three high as well as gather blocks. They came up with the design that enables them to pick up ...
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1answer
5k views

How does a two-gear pull-back car toy work?

This is not a robotics question, but this Stack Exchange is the closest I could find to mechanical engineering. Please refer me to a better place to ask this, if one exists. Hopefully someone might ...
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1answer
116 views

Mechanism to oscillate a needle like object in vertical motion

I need to pop out a needle like object(toothpick,matchstick,etc) from a hole in a surface and push it back in automatically.I need to make a array of such needles in which each needle's position can ...
1
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1answer
28 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 ...