Questions tagged [dynamics]
Questions about the dynamics of a system. Currently there is a very large scope ranging from from dynamics in mechanics, vehicle and flight dynamics, to system dynamics and fluid dynamics.
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Amplitude of superposition of forces
Find the amplitude of forces of superposition of 300cos13πt, 500sin6.4 πt + 300sin 13πt +600cos 18.8 πt
My answer is sqrt((300^2)+300^2) = 424 after superimposing both cos13πt and sin13πt, After which,...
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Control state space with perturbation
I have a system for which I have two variables that I want to control, let's say the position $x$ and a force $z$. I only know the dynamics of x in the form:
$$\dot{x}=Ax+Bu+Wz$$
where $u$ is my ...
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How was the length of the damper calculated in this figure?
I was reading this research and tried to calculate the length of the damper but couldn't figure out how. tried using the Law of Cosines but ended up with a different result.
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Can a bevel gearbox be used where the housing also rotates?
We are in the process of designing a custom machine, in which power from a motor has to be distributed to 4 shafts, while the axis of the shafts themselves rotate around a central axis. I hope it is ...
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How the displacement of the MRD piston is calculated in this Above knee prosthetic?
given that BD is perpendicular on AB,
E is in the middle of BF,
lengths of AB, BD, BF, BE are known,
theta1 and theta2 are the angles of hip and knee respectfully, the ankle is considered fixed.
only ...
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How to calculate the centrifugal impulse in the y direction?
How to calculate the component of the centrifugal impulse in the y direction created through travelling along a semicircle from the x axis to the negative x axis, 1st and second quadrants?
I am trying ...
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Engineering Dynamics Problem: Torque Comparison for Single Rod in Upward vs Downward Swing
I am currently researching the upward and downward swinging motions of landing gear mechanisms. I aim to determine whether there is a torque difference for the rod during the upward and downward ...
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How Do Length of Pylon and Rotor Disk Radius Impact Angular Frequency and Torsional Stiffness in Whirl Flutter Analysis for a 2 DOF Propeller System?
Actually, I'm having trouble implementing the plot of the flutter region for the whirl prop system with 2 DOF (Influences of structural damping and propeller—pivot point distance on whirl flutter ...
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Generate trajectory between 2 points to achieve a desired momentum
I need to plan path for robotic arm(having a tennis racquet as end-effector) whose aim is to hit a tennis ball in a specific direction(to return ball to the opponent). Now I have an algorithm which ...
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Engineering Dynamics Problem (Newton's Method vs. Energy and Momentum Methods)
Sorry to bother everyone,this is my first time posting on this forum.
I am currently conducting a study on landing gear mechanisms, specifically focusing on optimizing their dynamic performance. I am ...
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Does moving the idler in a wheel and disk CVT conserve energy or momentum?
Consider the wheel and disk CVTs (continuous variable transmissions) below. Configuration A comprises a CVT disk coupled to the "system under control" 's', whereby a control wheel 'cw' ...
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Why do period and damping ratio affect acceleration?
In the table above, the period of the structure $(T)$, the acceleration coefficient on the structure ($g$ in terms of gravitational acceleration) $Sa(T)$, The damping ratio is expressed as $ζ$ .
As ...
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How to model a two mass-spring-damper system with a bilinear spring with preload
So, first of all hello👋
I'm new to this forum.
Concerning my question, the system I want to model is a somewhat slightly more complicated version of a two mass-spring-damper system (than treated in ...
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Is this metal-ball launching device realistic?
For a school project (college level in "engineering" studies), a classmate and I are trying to design a device that would propel a metal ball of about 0.8 kg to distances up to 12-14m. Its ...
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Changing the relative equilibrium position for a 2-mass spring-mass system
I am trying to solve a double spring-mass system that is positioned vertically (I currently have the pendulum at an angle of 0 in my code below). I derived the system of ODE's required, and I get this ...
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How to write Generalized-$\alpha$ methods in a Runge-Kutta-Nystrom tableau?
How can I write Generalized-$\alpha$ methods in a Runge-Kutta-Nystrom tableau?
Thanks
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Calculating velocity of two different weight in a system with spring
I get a question like this. But what if the angle is given as theta=60° and I'm required to find the velocity of each weight. I tried the work energy equation but it doesn't seem to work since there ...
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translational kinetic energy and rotational kinetic energy
In a lever system, are there translational kinetic energy and rotational kinetic energy if the center of mass is at the centroid? and If the center of mass changes?
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Keeping a cardholder hanging from a lanyard always facing the same side
I always have the problem of having my ID cardholder flipping when I'm walking, and people not being able to see the side with the information.
I cannot double-print this ID front and back so I wonder:...
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How and why is kinematic control implemented?
First off, I apologize for what is likely a rather broad and formless question (and an even more broad and formless title). I'm a mathematician whose work sometimes carries him to control systems due ...
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Jitter Experienced by Spacecraft from Reaction Wheel Imbalances
I am working on a project trying to model a satellite's pointing error caused by jitter from the reaction wheels. I have found a couple of papers (Paper 1 and Paper 2) which implement the simple model ...
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Topology optimization issue (or not an issue, which is the issue)
I am currently doing some work in topology optimization regarding optimizing for the dynamic compliance of a beam structure but I am running into some issues. Well actually I am not running into some ...
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Inverted pendulum PID: controller causes cart to move at constant velocity?
I am trying to understand the PID controller of an inverted pendulum on cart system through this MATLAB article: https://ctms.engin.umich.edu/CTMS/index.php?example=InvertedPendulum§ion=...
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Modeling of Wheel Rolling Resistance
I have been working on longitudinal tire model for a while and constantly encounter problems with the formulation of rolling resistance. Consider one wheel model coming down from a damp. It is a 2DOF ...
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Is it possible to design the gain Kp for the system in the image, given it is underdamped and has a settling time of 2 seconds. Thank you
$$G(s) = \frac{K_P}{(s+2)^2}$$
$$H(s) = s+4$$
I keep getting Kp = 0 which leads to a damping ratio of 1 which isn't underdamped. To find Kp = 0, I found the closed loop transfer function and compared ...
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Spring constant of angled beam
I'm trying to solve for the dynamics of three blocks, shown below. Two blocks are pushed into a central shuttle, and their force is transmitted through a thin angled beam/pawl. The pawl bends when ...
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Distributed load on a slope/axle
In statics they teach you about distributed beams, how to calculate the total force, the engagement point, etc. I can't find any information anywhere on distributed loads on unevenly sloped surfaces / ...
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How do you go about picking a belt in design?
So when you want to pick a beam to use or determining the thickness of a load bearing beam, or picking bearings, there is some calculations you do to see if its life expectancy or f.s or to see if the ...
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Question about dynamics n-t coordinate system
et = tangential unit vector
en = unit vector in normal direction
I'm currently studying dynamics and I'm having difficulty understanding the process of obtaining det and det/dt in the n-t coordinate ...
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How to calculate the centripetal force along a cartesian axis?
If a centrifuge without a ballast is centered on the origin of an x-y coordinate plane, and starts at the x-axis rotating with increasing velocity counter-clockwise around the origin, how can the ...
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Linkage Mechanism Doubt
I am unsure how I would solve this. I have tried to solve it and got -29.1 but my attempt was wrong.
Could someone please lead me in the right direction or show me the way to solve this?
Thank you.
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Why can’t we accelerate a rotating object after some point?
If I push an object in a linear way with constant force bigger than frictional force on ground, the object will accelerate more and more until air drag force matches it. Logically, If I add the same ...
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How does 2nd gear create more thrust than 1st gear?
Let’s analyze a vehicle parallel to velocity and forces applying on it.
The 1st gear has a maximum velocity value after which you can’t accelerate more. It means that thrust force on wheels generated ...
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Torque created at bottom left corner due to torque in centre of 2D box
If I have a 2D box with uniform mass of width $w$ and height $h$. I apply a torque $\tau_O$ to the centre of the box, labeled $O$. The box has a fixed point $A$ at the bottom left around which it may ...
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Effect of Earth's rotation on moving vehicles
The earth rotates at a rate of 460 m/second. I wish to predict the position and approach for landing an UAV (quadcopter) on the vehicle.
I have a free-moving landing platform on vehicle that aligns ...
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Minimum torque required to turn a large gear
I want to preface this by saying that this isn't homework, it's just a question I've made up myself (so it could just be impossible to solve), and I am a beginner so apologies if I miss something ...
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Investigation of Body Motion in SolidWorks: Euler Angles Rate or Angular Velocity?
This is my first question in this community.
I decided to demonstrate my problem on simple rigid body, but task may be applied to more complex shapes. So, a cube is built in SolidWorks:
Using the ...
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Intermediate Dynamic Equation of Motion
If I were to determine the equations of motion for a symmetric top that is both spinning and allowed to translate in a single horizontal direction via its contact point.
How would I determine the ...
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Where will the load be applied on the beam
In a Newton's cradle, just like the one from the picture, where will the load of the spheres be applied on the right-hand beam?
Will it be a transverse load? The wire is connected laterally, not at ...
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Center of gravity offset for accelerometer and gyroscope readings
I am working on a 6DOF IMU that contains a 3 Axis Accelerometer and a 3 Axis Gyroscope.
I am building a project to plot the postion and orientation of the turret/cabin in a crane in 3D space.
The IMU ...
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Tensor of inertia of a curved beam
I need help calculating the inertia tensor for a curved beam.
I found the formulas for this in the article https://hal.archives-ouvertes.fr/hal-01084693/document[page 20, Appendix A] and decided to ...
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Transfer function to get linear velocity from a dc motor system
So I have to create a control system simulation from scratch for the following scenario. For a bicycle-like system, there is a motor attached directly to the rear wheel. From here, the goal of the ...
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Lewis form factor in between teeth
I’ve got total gear ratio of 3.428 but it’s a double step up gearbox. So I have to sq root it get the ratio of the pairs which is 1.851. For the small cog I have to use a min of 18 teeth. So teeth x g ...
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State Space Modeling nonlinear terms of vehicle’s longitudinal motion
My project is to build a software to help drivers achieve ecodriving thanks to optimal control based advices. Consequently, to feed a linear quadratic regulator, vehicle longitudinal equation of ...
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What would the dynamics and measurement operators be in this control theory problem/code, and where can I generate them from?
I'm working on something slightly outside of my scope of work, and I can't figure out if I fully understand what these things mean. Could someone help explain what the dynamics operator and ...
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How to determine which variables are state or input variables in dynamic modeling?
When given a P&ID and a process flow diagram, and asked to determine which of the relevant variables to a process input variables, and which are state variables (eg.: mass flow, temperature, ...
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Running a Dynamic Model as Steady State with Time Varying Inputs
I am attempting to run a dynamic model of a waste heat recovery system (Brayton Cycle with intercooling) on IDAES but I keep getting errors on initilization seemingly no matter what I do. My work ...
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Kinematics of actuated disk with no slip
Given the following kinematic problem, how would one calculate the velocity $v_C$ of point C given a certain horizontal velocity $v_{E}$ in point E? Given is that the disk does not slip and cannot ...
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Analysis of a Beam under Non-static Case
I am interested in the distribution of the beam in nonstatic cases.
Typically we discuss the stress, and moment distribution when a beam is in a static case.
However, I am interested in this ...
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