12 votes
Accepted

Calculating torque needed to climb a graded hill

I think you're overcomplicating things. To push 85 kg up a 15% slope against gravity of 9.8 m/s2 requires a force of $$ \sin (\arctan (0.15) ) = 0.1483 \approx 0.15 $$ $$F = 85 kg \cdot 9.8 \frac{m}...
  • 6,814
7 votes
Accepted

Feedback control of two-link planar manipulator

Convert the nonlinear model to state-space form, $x'=f(x,u)$, and linearize it to get a linear state-space or transfer function representation. You can use this to design a PID controller and simulate ...
  • 1,891
6 votes
Accepted

Applications of Five-Bar Mechanisms

Six bar linkages are pretty easy to find. Six bar is the go to guy when a four bar does not offer enough movement flexibility. Bigger European style hidden hinges are nearly all six bar mechanisms, ...
  • 3,435
5 votes

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 ...
5 votes
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
4 votes

How do you find the kinematic degrees of freedom of a mechanism?

It's a question of how many independent variables you need in order to write out the equations of motion. Let's walk through it step by step. Start by just considering Pulley 1 and Mass A. If they'...
  • 2,780
4 votes

How to calculate the velocity of a piston-like linkage?

The angle $\beta$ can be obtained from the geometry $$ 0.2*1000 \sin (\beta )+50 \sin (60 {}^{\circ})=150 $$ This gives $\beta = 0.5627 rad$. Assuming the angular velocity of the arm relative to B ...
  • 1,891
3 votes
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 ...
  • 1,307
3 votes
Accepted

How to interpete the formula: $I_{G}\alpha = \dot{\vec{H}}$?

Perhaps it is helpful to compare the equation to its linear counterpart. $$ \begin{align} \vec{F}&=\dot{\vec{p}}=m\vec{a}=m\dot{\vec{v}}\\ \vec{\tau}&=\dot{\vec{H}}=I\vec{\alpha}=I\dot{\vec{\...
3 votes
Accepted

Why do 2 points on a mechanism not have the same angular velocities?

The velocity of P' is perpendicular to AD, and the velocity of P is perpendicular to BP. So clearly the directions are not the same. Thus there is relative velocity between P and P' as shown in the ...
  • 1,891
3 votes

How do you find the kinematic degrees of freedom of a mechanism?

I often approach this type of problem by identifying constraints. Each independent constraint limits the number of degrees of freedom, required to completely define the system. $$DOF = DOF_{system} -...
  • 743
3 votes
Accepted

What are the basic mechanism, components or parts to generate relative movements?

There is a fascinating historical collection of mechanisms compiled in the late 19th century here: Mechanical Movements and somebody is working through the task of making animations of them for the ...
  • 12.6k
3 votes
Accepted

GIM Mechanism Software (Kinematics / Analysis / Synthesis)

Okay, it took me way too long to figure this out. I'm thinking this is just not a very intuitive interface. Here's the fix for anybody else who makes it here. Click #1, Click #2 (carefully!), then ...
  • 281
3 votes

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/...
  • 5,148
3 votes
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 ...
  • 1,603
3 votes
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 ...
2 votes

4 bar mechanism how does this 4 point method work

Answer The other ground link is not shown and neither is the floating link. This diagram only shows The 4 desired output link positions The 6 poles generated from those positions The process ...
  • 1,167
2 votes

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
2 votes

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 ...
2 votes
Accepted

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
2 votes

Bending Moment Doubt

When you constrain a beam end to point in the same direction as the clamped end (which is the case with the lower beams), then you have to apply a moment equal to $Ql$ (where $Q$ is the end load and $...
2 votes
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 ...
  • 2,283
2 votes
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 ...
  • 21.4k
2 votes

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
2 votes
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) ...
  • 23k
2 votes

Why does the 1kg mass move towards inclined plane here?

Let's assume for now the wedge S massless. its mass is not going the change the aspect of the behavior of the One kg mass. The components of the 1 kg along and perpendicular to the ramp are $$F_{...
  • 21.4k
2 votes
Accepted

Would a car slip down on a frictionless banked road and situation for friction road

Frictionless surface. Assuming the initial velocity is perfectly tangential to the circular motion to begin with : greater than $u_0 >\sqrt{g R \sin\theta}$, then the car will spiral outwards less ...
  • 23k
2 votes
Accepted

Frictional wheels without slipping (gear system)

The concept behind the friction force should always be greater than the tangential force is that the maximum friction force should be greater to the force that causes the rotation of the wheel. If ...
  • 23k
2 votes

Radial and transverse velocity

You could calculate the velocity magnitude from total energy (gravitational and kinetic) of the comet, which must be constant: $$E = E_p+E_k = -\frac{G\cdot M\cdot m}{r_A}+\frac{1}{2}m\cdot v_A^2 = -\...
1 vote

What is meant by "shock load" in gears?

In gear design for different machinery there is a combination of loads that causes damage and excessive wear and the equation for that load: F* = Ka Kv Km Ft Ka is application factor inherent ...
  • 21.4k

Only top scored, non community-wiki answers of a minimum length are eligible