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Accelerometers Used in the Measurement of Jerk, Snap, and Crackle
Accelerometers used in the measurement of jerk, snap, and crackle David Eager Faculty of Engineering and IT, University of Technology Sydney, PO Box 123 Broadway, Australia ABSTRACT Accelerometers are traditionally used in acoustics for the measurement of vibration. Higher derivatives of motion are rarely considered when measuring vibration. This paper presents a novel usage of a triaxial accelerometer to measure acceleration and use these data to explain jerk and higher derivatives of motion. We are all familiar with the terms displacement, velocity and acceleration but few of us are familiar with the term jerk and even fewer of us are familiar with the terms snap and crackle. We experience velocity when we are displaced with respect to time and acceleration when we change our velocity. We do not feel velocity, but rather the change of velocity i.e. acceleration which is brought about by the force exerted on our body. Similarly, we feel jerk and higher derivatives when the force on our body experiences changes abruptly with respect to time. The results from a gymnastic trampolinist where the acceleration data were collected at 100 Hz using a device attached to the chest are pre- sented and discussed. In particular the higher derivates of the Force total eQuation are extended and discussed, 3 3 4 4 5 5 namely: ijerk∙d x/dt , rsnap∙d x/dt , ncrackle∙d x/dt etc. 1 INTRODUCTION We are exposed to a wide variety of external motion and movement on a daily basis. From driving a car to catching an elevator, our bodies are repeatedly exposed to external forces acting upon us, leading to acceleration. -
AN00118-000 Motion Profiles.Doc
A N00118-000 - Motion Profiles Related Applications or Terminology Supported Controllers ■ Trapezoidal Velocity Profile NextMovePCI NextMoveBXII ■ S-Ramped Velocity Profile NextMoveST NextMoveES Overview MintDriveII The motion of moving objects can be specified by a number of Flex+DriveII parameters, which together define the Motion Profile. These parameters are: Relevant Keywords Speed: The rate of change of position PROFILEMODE Acceleration: The rate of change of speed during an SPEED ACCEL increase of speed. DECEL Deceleration: The rate of change of speed during a ACCELJERK decrease of speed. DECELJERK Jerk: The rate of change of acceleration or deceleration. Trapezoidal Profile A trapezoidal profile is typically made up of three sections, an acceleration phase, a constant velocity phase and a deceleration phase. Velocity Time Acceleration Constant Velocity Deceleration © Baldor UK Ltd 2003 1 of 6 AN00118-000 Motion Profiles.doc The graph is a plot of velocity against time for a trapezoidal profile; the name reflects the shape of the profile. For a positional move from rest, the velocity increases at the rate defined by acceleration until it reaches the slew speed. The velocity will then remain constant until the deceleration point, where the velocity will then decrease to a halt at the rate specified by deceleration. S-Ramped Profile An s-ramped profile can be considered as a super set of the trapezoidal profile. It typically is made up of seven sections, four jerk phases on top of the acceleration phase, constant velocity phase and deceleration phase. Velocity Time Acceleration Constant Velocity Deceleration The graph is a plot of velocity against time for an s-curve profile; again the name reflects the shape of the profile. -
On Fast Jerk–, Acceleration– and Velocity–Restricted Motion Functions for Online Trajectory Generation
robotics Article On Fast Jerk–, Acceleration– and Velocity–Restricted Motion Functions for Online Trajectory Generation Burkhard Alpers Department of Mechanical Engineering, Aalen University, D-73430 Aalen, Germany; [email protected] Abstract: Finding fast motion functions to get from an initial state (distance, velocity, acceleration) to a final one has been of interest for decades. For a solution to be practically relevant, restrictions on jerk, acceleration and velocity have to be taken into account. Such solutions use optimization algorithms or try to directly construct a motion function allowing online trajectory generation. In this contribution, we follow the latter strategy and present an approach which first deals with the situation where initial and final accelerations are 0, and then relates the general case as much as possible to this situation. This leads to a classification with just four major cases. A continuity argument guarantees full coverage of all situations which is not the case or is not clear for other available algorithms. We present several examples that show the variety of different situations and, thus, the complexity of the task. We also describe an implementation in MATLAB® and results from a huge number of test runs regarding accuracy and efficiency, thus demonstrating that the algorithm is suitable for online trajectory generation. Keywords: online trajectory generation; fast motion functions; seven segment profile; jerk restriction 1. Introduction Citation: Alpers, B. On Fast Jerk–, Acceleration– and Velocity–Restricted For achieving high throughput in handling machines, one of the most basic tasks Motion Functions for Online consists of quickly moving from one position to the next one, taking into account machine Trajectory Generation. -
Jerk and Hyperjerk in a Rotating Frame of Reference
Jerk and Hyperjerk in a Rotating Frame of Reference Amelia Carolina Sparavigna Department of Applied Science and Technology, Politecnico di Torino, Italy. Abstract: Jerk is the derivative of acceleration with respect to time and then it is the third order derivative of the position vector. Hyperjerks are the n-th order derivatives with n>3. This paper describes the relations, for jerks and hyperjerks, between the quantities measured in an inertial frame of reference and those observed in a rotating frame. These relations can be interesting for teaching purposes. Keywords: Rotating frames, Physics education research. 1. Introduction Jerk is the rate of change of acceleration, that is, it is the derivative of acceleration with respect to time [1,2]. In teaching physics, jerk is often completely neglected; however, as remarked in the Ref.1, it is a physical quantity having a great importance in practical engineering, because it is involved in mechanisms having rotating or sliding pieces, such as cams and genevas. For this reason, jerks are commonly found in models for the design of robotic arms. Moreover, these derivatives of acceleration are also considered in the planning of tracks and roads, in particular of the track transition curves [3]. Let us note that, besides in mechanics and transport engineering, jerks can be used in the study of several electromagnetic systems, as proposed in the Ref.4. Jerks of the geomagnetic field are investigated too, to understand the dynamics of the Earth’s fluid, iron-rich outer core [5]. Jerks and hyperjerks - jerks having a n-th order derivative with n>3 - are also attractive for researchers that are studying the behaviour of complex systems. -
Speed Profile Optimization for Enhanced Passenger Comfort: an Optimal Control Approach Yuyang Wang, Jean-Rémy Chardonnet, Frédéric Merienne
Speed Profile Optimization for Enhanced Passenger Comfort: An Optimal Control Approach Yuyang Wang, Jean-Rémy Chardonnet, Frédéric Merienne To cite this version: Yuyang Wang, Jean-Rémy Chardonnet, Frédéric Merienne. Speed Profile Optimization for Enhanced Passenger Comfort: An Optimal Control Approach. 2018 21st International Conference on Intelligent Transportation Systems (ITSC), Nov 2018, Maui, Hawaii, United States. pp.723-728. hal-01963942 HAL Id: hal-01963942 https://hal.archives-ouvertes.fr/hal-01963942 Submitted on 21 Dec 2018 HAL is a multi-disciplinary open access L’archive ouverte pluridisciplinaire HAL, est archive for the deposit and dissemination of sci- destinée au dépôt et à la diffusion de documents entific research documents, whether they are pub- scientifiques de niveau recherche, publiés ou non, lished or not. The documents may come from émanant des établissements d’enseignement et de teaching and research institutions in France or recherche français ou étrangers, des laboratoires abroad, or from public or private research centers. publics ou privés. Speed Profile Optimization for Enhanced Passenger Comfort: An Optimal Control Approach Yuyang Wangy, Jean-Remy´ Chardonnet and Fred´ eric´ Merienne Abstract— Autonomous vehicles are expected to start reach- We propose a novel approach in which we generate a glob- ing the market within the next years. However in practical ally lowest jerk trajectory with an optimized speed profile applications, navigation inside dynamic environments has to following also the same comfort constraints as defined in take many factors such as speed control, safety and comfort into consideration, which is more paramount for both passengers the ISO 2631-1 standard [5]. We achieve this by introducing and pedestrians. -
Equipartition of Energy
Equipartition of Energy The number of degrees of freedom can be defined as the minimum number of independent coordinates, which can specify the configuration of the system completely. (A degree of freedom of a system is a formal description of a parameter that contributes to the state of a physical system.) The position of a rigid body in space is defined by three components of translation and three components of rotation, which means that it has six degrees of freedom. The degree of freedom of a system can be viewed as the minimum number of coordinates required to specify a configuration. Applying this definition, we have: • For a single particle in a plane two coordinates define its location so it has two degrees of freedom; • A single particle in space requires three coordinates so it has three degrees of freedom; • Two particles in space have a combined six degrees of freedom; • If two particles in space are constrained to maintain a constant distance from each other, such as in the case of a diatomic molecule, then the six coordinates must satisfy a single constraint equation defined by the distance formula. This reduces the degree of freedom of the system to five, because the distance formula can be used to solve for the remaining coordinate once the other five are specified. The equipartition theorem relates the temperature of a system with its average energies. The original idea of equipartition was that, in thermal equilibrium, energy is shared equally among all of its various forms; for example, the average kinetic energy per degree of freedom in the translational motion of a molecule should equal that of its rotational motions. -
Fastest Frozen Temperature for a Thermodynamic System
Fastest Frozen Temperature for a Thermodynamic System X. Y. Zhou, Z. Q. Yang, X. R. Tang, X. Wang1 and Q. H. Liu1, 2, ∗ 1School for Theoretical Physics, School of Physics and Electronics, Hunan University, Changsha, 410082, China 2Synergetic Innovation Center for Quantum Effects and Applications (SICQEA), Hunan Normal University,Changsha 410081, China For a thermodynamic system obeying both the equipartition theorem in high temperature and the third law in low temperature, the curve showing relationship between the specific heat and the temperature has two common behaviors: it terminates at zero when the temperature is zero Kelvin and converges to a constant value of specific heat as temperature is higher and higher. Since it is always possible to find the characteristic temperature TC to mark the excited temperature as the specific heat almost reaches the equipartition value, it is also reasonable to find a temperature in low temperature interval, complementary to TC . The present study reports a possibly universal existence of the such a temperature #, defined by that at which the specific heat falls fastest along with decrease of the temperature. For the Debye model of solids, below the temperature # the Debye's law manifest itself. PACS numbers: I. INTRODUCTION A thermodynamic system usually obeys two laws in opposite limits of temperature; in high temperature the equipar- tition theorem works and in low temperature the third law of thermodynamics holds. From the shape of a curve showing relationship between the specific heat and the temperature, the behaviors in these two limits are qualitatively clear: in high temperature it approaches to a constant whereas it goes over to zero during the temperature is lowering to the zero Kelvin. -
Exercise 18.4 the Ideal Gas Law Derived
9/13/2015 Ch 18 HW Ch 18 HW Due: 11:59pm on Monday, September 14, 2015 To understand how points are awarded, read the Grading Policy for this assignment. Exercise 18.4 ∘ A 3.00L tank contains air at 3.00 atm and 20.0 C. The tank is sealed and cooled until the pressure is 1.00 atm. Part A What is the temperature then in degrees Celsius? Assume that the volume of the tank is constant. ANSWER: ∘ T = 175 C Correct Part B If the temperature is kept at the value found in part A and the gas is compressed, what is the volume when the pressure again becomes 3.00 atm? ANSWER: V = 1.00 L Correct The Ideal Gas Law Derived The ideal gas law, discovered experimentally, is an equation of state that relates the observable state variables of the gaspressure, temperature, and density (or quantity per volume): pV = NkBT (or pV = nRT ), where N is the number of atoms, n is the number of moles, and R and kB are ideal gas constants such that R = NA kB, where NA is Avogadro's number. In this problem, you should use Boltzmann's constant instead of the gas constant R. Remarkably, the pressure does not depend on the mass of the gas particles. Why don't heavier gas particles generate more pressure? This puzzle was explained by making a key assumption about the connection between the microscopic world and the macroscopic temperature T . This assumption is called the Equipartition Theorem. The Equipartition Theorem states that the average energy associated with each degree of freedom in a system at T 1 k T k = 1.38 × 10−23 J/K absolute temperature is 2 B , where B is Boltzmann's constant. -
Lecture 8 - Dec 2, 2013 Thermodynamics of Earth and Cosmos; Overview of the Course
Physics 5D - Lecture 8 - Dec 2, 2013 Thermodynamics of Earth and Cosmos; Overview of the Course Reminder: the Final Exam is next Wednesday December 11, 4:00-7:00 pm, here in Thimann Lec 3. You can bring with you two sheets of paper with any formulas or other notes you like. A PracticeFinalExam is at http://physics.ucsc.edu/~joel/Phys5D The Physics Department has elected to use the new eCommons Evaluations System to collect end of the quarter instructor evaluations from students in our courses. All students in our courses will have access to the evaluation tool in eCommons, whether or not the instructor used an eCommons site for course work. Students will receive an email from the department when the evaluation survey is available. The email will provide information regarding the evaluation as well as a link to the evaluation in eCommons. Students can click the link, login to eCommons and find the evaluation to take and submit. Alternately, students can login to ecommons.ucsc.edu and click the Evaluation System tool to see current available evaluations. Monday, December 2, 13 20-8 Heat Death of the Universe If we look at the universe as a whole, it seems inevitable that, as more and more energy is converted to unavailable forms, the total entropy S will increase and the ability to do work anywhere will gradually decrease. This is called the “heat death of the universe”. It was a popular theme in the late 19th century, after physicists had discovered the 2nd Law of Thermodynamics. Lord Kelvin calculated that the sun could only shine for about 20 million years, based on the idea that its energy came from gravitational contraction. -
An Alternative Approach to Jerk in Motion Along a Space Curve with Applications
JOURNAL OF THEORETICAL AND APPLIED MECHANICS 57, 2, pp. 435-444, Warsaw 2019 DOI: 10.15632/jtam-pl/104595 AN ALTERNATIVE APPROACH TO JERK IN MOTION ALONG A SPACE CURVE WITH APPLICATIONS Kahraman Esen Ozen¨ Sakarya University, Mathematics Department, Sakarya, Turkey; e-mail: [email protected] Furkan Semih Dundar¨ Boˇgazi¸ci University, Physics Department, Istanbul, Turkey; e-mail: [email protected] Murat Tosun Sakarya University, Mathematics Department, Sakarya, Turkey; e-mail: [email protected] Jerk is the time derivative of an acceleration vector and, hence, the third time derivative of the position vector. In this paper, we consider a particle moving in the three dimensional Euclidean space and resolve its jerk vector along the tangential direction, radial direction in the osculating plane and the other radial direction in the rectifying plane. Also, the case for planar motion in space is given as a corollary. Furthermore, motion of an electron under a constant magnetic field and motion of a particle along a logarithmic spiral curve are given as illustrative examples. The aforementioned decomposition is a new contribution to the field and it may be useful in some specific applications that may be considered in the future. Keywords: jerk, kinematics of a particle, plane and space curves 1. Introduction In Newtonian physics, the force acting on the particle is related to its acceleration through F = ma. The jerk J is the time derivative of the acceleration. Therefore, if the mass is constant, we have J = (1/m)dF/dt. If the time derivative of the force is nonzero, we have a nonzero jerk vector. -
Thermodynamic Temperature
Thermodynamic temperature Thermodynamic temperature is the absolute measure 1 Overview of temperature and is one of the principal parameters of thermodynamics. Temperature is a measure of the random submicroscopic Thermodynamic temperature is defined by the third law motions and vibrations of the particle constituents of of thermodynamics in which the theoretically lowest tem- matter. These motions comprise the internal energy of perature is the null or zero point. At this point, absolute a substance. More specifically, the thermodynamic tem- zero, the particle constituents of matter have minimal perature of any bulk quantity of matter is the measure motion and can become no colder.[1][2] In the quantum- of the average kinetic energy per classical (i.e., non- mechanical description, matter at absolute zero is in its quantum) degree of freedom of its constituent particles. ground state, which is its state of lowest energy. Thermo- “Translational motions” are almost always in the classical dynamic temperature is often also called absolute tem- regime. Translational motions are ordinary, whole-body perature, for two reasons: one, proposed by Kelvin, that movements in three-dimensional space in which particles it does not depend on the properties of a particular mate- move about and exchange energy in collisions. Figure 1 rial; two that it refers to an absolute zero according to the below shows translational motion in gases; Figure 4 be- properties of the ideal gas. low shows translational motion in solids. Thermodynamic temperature’s null point, absolute zero, is the temperature The International System of Units specifies a particular at which the particle constituents of matter are as close as scale for thermodynamic temperature. -
Kinetic Energy of a Free Quantum Brownian Particle
entropy Article Kinetic Energy of a Free Quantum Brownian Particle Paweł Bialas 1 and Jerzy Łuczka 1,2,* ID 1 Institute of Physics, University of Silesia, 41-500 Chorzów, Poland; [email protected] 2 Silesian Center for Education and Interdisciplinary Research, University of Silesia, 41-500 Chorzów, Poland * Correspondence: [email protected] Received: 29 December 2017; Accepted: 9 February 2018; Published: 12 February 2018 Abstract: We consider a paradigmatic model of a quantum Brownian particle coupled to a thermostat consisting of harmonic oscillators. In the framework of a generalized Langevin equation, the memory (damping) kernel is assumed to be in the form of exponentially-decaying oscillations. We discuss a quantum counterpart of the equipartition energy theorem for a free Brownian particle in a thermal equilibrium state. We conclude that the average kinetic energy of the Brownian particle is equal to thermally-averaged kinetic energy per one degree of freedom of oscillators of the environment, additionally averaged over all possible oscillators’ frequencies distributed according to some probability density in which details of the particle-environment interaction are present via the parameters of the damping kernel. Keywords: quantum Brownian motion; kinetic energy; equipartition theorem 1. Introduction One of the enduring milestones of classical statistical physics is the theorem of the equipartition of energy [1], which states that energy is shared equally amongst all energetically-accessible degrees of freedom of a system and relates average energy to the temperature T of the system. In particular, for each degree of freedom, the average kinetic energy is equal to Ek = kBT/2, where kB is the Boltzmann constant.