# Tag Info

Accepted

### What does it mean for a machine design to be "kinematic"?

I think it might be shorthand for a kinematically constrained design. It is the ...
• 166

### What do I need to operate this motor?

I recommend researching motor driver circuits. These motor drivers internal has a H-Bridge design and have both direct on of digital signal to manage both direction (forward, backwards) and stop. You ...
• 7,135

### Mechanical Engineering: How To Amplify Kinetic Energy In Axial Rotational Gear Machinery?

A simple machine is what you're referring to. A simple machine turns motion into mechanical advantage. Examples include: lever inclined plane pulleys wheel & axle gears inclined plane/wedge/...
• 7,074
Accepted

### 4 Gears in a Circular Pattern - Calculating the Proper Distances for Meshing

Let’s consider gears as being represented by a pitch circle on which lie several equally spaced dots with a number equal to the number of teeth. These dots can either represent the teeth or the gaps ...
• 1,327
Accepted

### Inverse of quaternion kinematic matrix

In order to make the notation shorter for the remaining calculations in my answer I will denote the matrix with $$H = \frac{1}{2} \begin{bmatrix} -q^\top \\ q_0\,I_3 + q^\times \end{bmatrix}.$$ In ...
• 1,663
Accepted

### Is there a simple trigonometric relationship between these two angles?

Since considering four-bar linkages is a useful tool in my research field, I happen to know of a paper that precisely solves what you want to do. George H. Martin published in 1958 in the journal ...
• 1,923

### Why can’t we accelerate a rotating object after some point?

This gets back to the original answer by Tigerguy. You have the maximum torque your legs can put out. You also have the maximum power your legs can put out (power = torque x rotational speed). But you ...
• 109
Accepted

### Relationship between how fast a metal cylinder can spin on its axis without breaking or deforming?

For a thin spinning disk ignoring the frictions, such as air friction, there are two stresses, radial and hoop stress. Both must be below the accepted stress limit of the material. We assume no ...
• 22.6k

### What is meant by "shock load" in gears?

a shock load on gearing is imposed when the gear train is forced to start or stop turning very suddenly, or when a heavy load is suddenly applied to a set of rotating gears. A good example of this is ...
• 15.1k
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### Questions on machinery terminology

Answering your first question: In the control field of mechanical engineering, a spring can indeed be a link. In the book Modern Control Engineering by Ogata, Katsuhiko the spring is frequently used ...
• 139

### Calculating torque needed to climb a graded hill

The answer provided by Dave is correct but it covers only a very specific case of no-friction and constant speed. There are three forces acting on a vechicle which must be accelerated from 0 to v ...
• 121
Accepted

### Purpose of normalization of Jacobian in a parallel manipulator

It is because you are using the trace of the matrix, which is equal to the sum of the singular values. The ideal $\mathbf{JJ^T}$ has singular values all equal to 1, but for an $n \times n$ matrix ...
• 2,692
Accepted

### To stop or to go around?

Each car depending on its handling has a maximum safe turning speed $v_{max}$, and radius $r$. Let us say the current speed $v<v_{max}$, then your turning angular velocity is $$\omega= v/r.$$ We ...
• 22.6k

### Mechanical Engineering: How To Amplify Kinetic Energy In Axial Rotational Gear Machinery?

No. You cannot increase both torque and speed without adding more energy to a system. In a gear train/belt & pulley combo, you have one member rotating slower but with higher torque and the other ...
• 2,347
Accepted

### Firing a bullet on wooden block and then finding the average resistive force by block?

There is no need to know the mass of the block. If it were movable yes, but in this case you can assume that is a fixed wall. So the whole idea is that you are assuming a constant (average) ...
• 24.4k

• 1,335
Accepted

### Kinematic join for parallel axis rotation with equal inverse angles

Depending on whether you care about accurate angles displacement you could use chains or belts. Configuration 1 - Belt Not accurate If then rotation angles don't have to be the same you can get away ...
• 24.4k

### Why can’t we accelerate a rotating object after some point?

This would work if input power could handle infinite speeds. On a bicycle, your legs limit how fast you can pedal and the power you can input to the system. Motors have speed limits as well. The ...
• 7,074
1 vote

### Degrees of Freedom for Complex Pulley Systems

I would argue that there are only 3 degrees of freedom in this system. Those can be the following (you can define others also): The idea behind the DOF is a motion that is required to describe the ...
• 24.4k
1 vote

### In circular motion , why do we say this is centripetal acceleration

I found this definition quite interesting, you can comment on it. "Centripetal acceleration is defined as the property of the motion of an object, traversing a circular path. Any object that is ...
• 8,247
1 vote

### In circular motion , why do we say this is centripetal acceleration

It's there to make the laws of motion work. An object in stable circular motion needs a force towards the center of the circle to keep it in circular motion. f=ma Pretty simply the force required to ...
• 7,074
1 vote

### Gear Ratio of a Stepped Planetary Gearset

The formula to use is, R= Number of teeth in ring gear S =Number of teeth in sun (middle) gear P= Number of teeth in planet gears And Tr Turns of the ring gear Ts Turns of the sun gear ...
• 22.6k
1 vote

### What does it mean for a machine design to be "kinematic"?

See https://en.m.wikipedia.org/wiki/Kinematic_coupling A kinematic coupling is constrained in (only) 6 degrees of freedom.
• 7,761
1 vote
Accepted

### Euler rotations and acceleration

First of all you need to be about which reference frame you are estimating the acceleration of A. I assume you need the accelation of A wrt to the inertial frame of reference. The most generic way is ...
• 24.4k
1 vote

### Maximum velocity of an athlete

The runner has two types of movement: accelerating from 0 to $v_c \quad a= \text{acceleration}$. Let's call the constant speed Vc. So the average speed on the first 15m is half of this. \$9.6=\frac{...
• 22.6k
1 vote

### I have the yaw rate, rear wheel speeds, and the radius of tires, how to find x and y speeds?

You're making the assumption, that all wheels are rolling without slip. Is it a front wheel driven vehicle? Slip could cause the deviations you see. So, what directional speed are you looking for? ...
• 181

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