DOCSLIB.ORG

Motor Vector Control Based on Speed-Torque-Current Map

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Motor Vector Control Based on Speed-Torque-Current Map applied sciences Article Motor Vector Control Based on Speed-Torque-Current Map Jianjun Hu 1,2,*, Meixia Jia 2, Feng Xiao 2, Chunyun Fu 2 and Lingling Zheng 2 1 State Key Laboratory of Mechanical Transmissions, Chongqing University, Chongqing 400044, China 2 School of Automotive Engineering, Chongqing University, Chongqing 400044, China; [email protected] (M.J.); [email protected] (F.X.); [email protected] (C.F.); [email protected] (L.Z.) * Correspondence: [email protected]; Tel.: +86-139-9607-3282 Received: 1 November 2019; Accepted: 16 December 2019; Published: 20 December 2019 Abstract: In order to effectively extend the mileage of pure electric vehicles, the influence of the electromechanical energy conversion principle and the dynamic control of a permanent magnet synchronous motor (PMSM) on the performance of pure electric vehicles are studied with a dual-motor drive system as a carrier in this paper. A vector control strategy based on the speed-torque-current map of a motor is proposed, considering the bus voltage fluctuation influenced by battery charge and discharge. By constructing a complete vehicle model including the dynamic control model of the motor, the power distribution control strategy of a dual-motor coupling mode considering the dynamic characteristics of the motor is developed and simulated on the MATLAB platform. The results show that the dynamic model of the motor is closer to the actual running conditions. The proposed control strategy effectively reduces the demand power, decreases the energy consumption of the electric drive system, and extends the mileage of the vehicle. Keywords: control strategy; dynamic control; pure electric vehicle; speed-torque-current map 1. Introduction As the only source of propulsion, the dynamic characteristics and the performance of the motor are very important to vehicles. In order to meet the needs of vehicle research, the study of motors from static control strategy to dynamic control strategy can make the vehicle run more efficiently. The efficiency and torque characteristics of the motor directly determine the effect of the control strategy. It also has a direct impact on the power loss of the motor and the mileage of the vehicle. In recent years, the permanent magnet synchronous motor (PMSM) is increasingly used as the power source in pure electric vehicles. Multi-power source systems are also taken seriously because of their wide efficiency range and multi-mode flexibility [1]. At present, the drive control strategy of a multi-power driven vehicle is mainly designed based on the static characteristics of the transmission system components [2]. In [3], a rule-based control strategy for a dual-motor coupling driven pure electric vehicle is designed to obtain the optimal acceleration performance. In [4], the dynamic programming algorithm is used to optimize the mode switching threshold value of a dual-motor coupling electric drive system with rotational speed coupling mode, and the optimized control strategy significantly improves the economic efficiency of the vehicle. Wang [5] comprehensively considered the problem of motor temperature rise, which leads to its efficiency and torque decline in the process of designing the coordinated control strategy of the whole vehicle powertrain. It effectively reduces the frequency of motor failure due to the temperature rising. Li [6] investigated the PMSM control system through combining the method of rotor field-oriented control and the space vector control strategy. Zhou [7] established the dynamic model of the PMSM and the efficiency model of the inverter Appl. Sci. 2020, 10, 78; doi:10.3390/app10010078 www.mdpi.com/journal/applsci Appl. Sci. 2020, 10, 78 2 of 21 module of the motor controller. He studied the speed and torque characteristics of the motor, as well as size and quality characteristics, and designed the control strategy based on torque compensation in the dynamic mode and economic mode. In order to improve the performance of PMSM when it is used as a motor to drive the vehicle, the working principle of this type of motor has been thoroughly analyzed, and its current vector control scheme is optimized [8–15]. Most of the motor dynamic models established by the above scholars are used to study the speed and torque response and energy consumption performance, but the influence of motor dynamic control on the vehicle drive control strategy has not been further studied. Furthermore, if only the static characteristics of components are considered in the formulation of the control strategy of the driving system, there will be a big discrepancy between the operating state of the system and the actual operation process. The influence of dynamic process and control on the performance of the vehicle cannot be ignored; otherwise, performance errors of the vehicle may be caused. The major defects of the static model are as follows. (1) In the static model, the speed and torque of the motor can step change; that is, the working point of the motor can step change instantaneously. However, in practical running, the change of the speed and the torque is not an ideal step process. If the static model is used as the basis of the driving strategy, its dynamic and economy performance have a large deviation from the actual running. (2) The actual operation of the motor is affected by the control parameters, and there is always torque fluctuation. However, these characteristics cannot be reflected in the static model. (3) In the process of coupling drive, the efficiency of different working modes is only considered in the static model, but the mode-switching process and the energy loss are ignored in the process. The dynamic model and control of the motor can fully respond to the whole process of mode operation and mode switching, which is in good agreement with the actual operation process of the motor. The combination of dynamic control and the multi-power vehicle model can reflect the characteristics of speed–torque and energy consumption. Exploring the influence of dynamic control on the performance of multi-power vehicles can be used to guide the formulation of the control strategy of a multi-power coupled electric drive system. The rest of the paper is organized as follows. Section2 introduces the electric drive system configuration and the main parameters that are used in the subsequent strategy. In Section3, a novel vector control strategy of PMSM based on the speed-torque-current map is proposed. Then, the proposed control strategy is validated in Section4 to evaluate the results of the running of the motor controlled by the new strategy. 2. Electric Drive System Configuration and Main Parameters The configuration of the dual-motor drive system [16] is shown in Figure1. The system consists of two drive motors (MG1 and MG2), one planetary gear, three clutches (C1, C2, and C3), one brake (B1), two gear pairs (Gear 1 and Gear 2), and one main reducer (Final Drive). This electric drive system can realize four working modes including MG1 driving alone (M1), MG2 driving alone (M2), torque coupling drive (M3), and speed coupling drive (M4), as shown in Figure2. The vehicle working modes and the corresponding component status are listed in Table1. Table 1. Vehicle working modes and the corresponding component status. This electric drive system can realize four working modes: MG1 driving alone (M1), MG2 driving alone (M2), torque coupling drive (M3), and speed coupling drive (M4). Mode MG1 MG2 C1 C2 C3 B Power Flow M1 M C OFF OFF ON OFF Figure2a M2 C M OFF ON OFF ON Figure2b M3 M M OFF ON ON ON Figure2c M4 M M ON ON OFF OFF Figure2d Appl. Sci. 2020, 10, x FOR PEER REVIEW 3 of 22 B1 C1 MG1 MG2 Gear 2 Gear 1 C3 C2 Final Drive Output shaft Appl. Sci. 2020, 10, 78 3 of 21 Appl. Sci. 2020, 10, x FOR PEER REVIEW 3 of 22 B1 C1 Figure 1. Electric drive system configuration. The system consists of two drive motors (MG1 and MG2), one planetary gear, three clutchesMG1 (C1, C2, and C3),MG2 one brake (B1), two gear pairs (Gear 1 and Gear 2), and one main reducer (Final Drive). Gear 2 Gear 1 C3 Table 1. Vehicle working modes and the corresponding component status. This electric drive system can realize four working modes: MG1C2 driving alone (M1), MG2 driving alone (M2), torque coupling drive (M3), and speed coupling drive (M4). Final Drive Output shaft Mode MG1 MG2 C1 C2 C3 B Power Flow M1 M C OFF OFF ON OFF Figure 2a M2 C M OFF ON OFF ON Figure 2b M3 M M OFF ON ON ON Figure 2c Figure 1. Electric drive system configuration. The system consists of two drive motors (MG1 and Figure 1. Electric drive system configuration. The system consists of two drive motors (MG1 and M4MG2), one planetaryM gear,M three clutchesON (C1, C2, andON C3), oneOFF brake (B1),OFF two gear pairs (GearFigure 1 and 2d MG2), one planetary gear, three clutches (C1, C2, and C3), one brake (B1), two gear pairs (Gear 1 and Gear 2), and one main reducer (Final Drive). Gear 2), and one main reducer (Final Drive). 功率流 B 功率流 B Table 1.Power Vehicle Flow working modes and the correspondingPower Flow component status. This electric drive system can realize four workingC1 modes: MG1 driving alone (M1), MG2C1 driving alone (M2), torque coupling MG2 drive (M3),MG1MG1 and speed coupling MG2driveMG2 (M4). MG1M1 MG2M2 Mode MG1 MG2 C1 C2 C3 B Power Flow C3 C3 M1 C2 M C OFF OFF C2ON OFF Figure 2a M2 C M OFF ON OFF ON Figure 2b M3 M M OFF ON ON ON Figure 2c M4 M M ON ON OFF OFF Figure 2d 功率流 B 功率流 （B ） Power Flow （a） Power Flow b C1 C1 MG1 MG2MG2 MG2 功率流 MG1 B MG2 功率流MG1M1 B MG2M2 Power Flow Power Flow C1 C1 C3 C3 MG1M1 MG2M2 MG1M1 MG2M2 C2 C2 C3 C3 C2 C2 （a） （b） 功率流 B 功率流 B Power Flow Power Flow C1 C1 M1 MG2M2 MG1 （c） MG1M1 （d）MG2M2 Figure 2.
Load more

Recommended publications
  • Motion Projectile Motion,And Straight Linemotion, Differences Between the Similaritiesand 2 CHAPTER 2 Acceleration Make Thefollowing As Youreadthe ●
    026_039_Ch02_RE_896315.qxd 3/23/10 5:08 PM Page 36 User-040 113:GO00492:GPS_Reading_Essentials_SE%0:XXXXXXXXXXXXX_SE:Application_File chapter 2 Motion section ●3 Acceleration What You’ll Learn Before You Read ■ how acceleration, time, and velocity are related Describe what happens to the speed of a bicycle as it goes ■ the different ways an uphill and downhill. object can accelerate ■ how to calculate acceleration ■ the similarities and differences between straight line motion, projectile motion, and circular motion Read to Learn Study Coach Outlining As you read the Velocity and Acceleration section, make an outline of the important information in A car sitting at a stoplight is not moving. When the light each paragraph. turns green, the driver presses the gas pedal and the car starts moving. The car moves faster and faster. Speed is the rate of change of position. Acceleration is the rate of change of velocity. When the velocity of an object changes, the object is accelerating. Remember that velocity is a measure that includes both speed and direction. Because of this, a change in velocity can be either a change in how fast something is moving or a change in the direction it is moving. Acceleration means that an object changes it speed, its direction, or both. How are speeding up and slowing down described? ●D Construct a Venn When you think of something accelerating, you probably Diagram Make the following trifold Foldable to compare and think of it as speeding up. But an object that is slowing down contrast the characteristics of is also accelerating. Remember that acceleration is a change in acceleration, speed, and velocity.
    [Show full text]
  • Frames of Reference
    Galilean Relativity 1 m/s 3 m/s Q. What is the women velocity? A. With respect to whom? Frames of Reference: A frame of reference is a set of coordinates (for example x, y & z axes) with respect to whom any physical quantity can be determined. Inertial Frames of Reference: - The inertia of a body is the resistance of changing its state of motion. - Uniformly moving reference frames (e.g. those considered at 'rest' or moving with constant velocity in a straight line) are called inertial reference frames. - Special relativity deals only with physics viewed from inertial reference frames. - If we can neglect the effect of the earth’s rotations, a frame of reference fixed in the earth is an inertial reference frame. Galilean Coordinate Transformations: For simplicity: - Let coordinates in both references equal at (t = 0 ). - Use Cartesian coordinate systems. t1 = t2 = 0 t1 = t2 At ( t1 = t2 ) Galilean Coordinate Transformations are: x2= x 1 − vt 1 x1= x 2+ vt 2 or y2= y 1 y1= y 2 z2= z 1 z1= z 2 Recall v is constant, differentiation of above equations gives Galilean velocity Transformations: dx dx dx dx 2 =1 − v 1 =2 − v dt 2 dt 1 dt 1 dt 2 dy dy dy dy 2 = 1 1 = 2 dt dt dt dt 2 1 1 2 dz dz dz dz 2 = 1 1 = 2 and dt2 dt 1 dt 1 dt 2 or v x1= v x 2 + v v x2 =v x1 − v and Similarly, Galilean acceleration Transformations: a2= a 1 Physics before Relativity Classical physics was developed between about 1650 and 1900 based on: * Idealized mechanical models that can be subjected to mathematical analysis and tested against observation.
    [Show full text]
  • Chapter 3 Motion in Two and Three Dimensions
    Chapter 3 Motion in Two and Three Dimensions 3.1 The Important Stuff 3.1.1 Position In three dimensions, the location of a particle is specified by its location vector, r: r = xi + yj + zk (3.1) If during a time interval ∆t the position vector of the particle changes from r1 to r2, the displacement ∆r for that time interval is ∆r = r1 − r2 (3.2) = (x2 − x1)i +(y2 − y1)j +(z2 − z1)k (3.3) 3.1.2 Velocity If a particle moves through a displacement ∆r in a time interval ∆t then its average velocity for that interval is ∆r ∆x ∆y ∆z v = = i + j + k (3.4) ∆t ∆t ∆t ∆t As before, a more interesting quantity is the instantaneous velocity v, which is the limit of the average velocity when we shrink the time interval ∆t to zero. It is the time derivative of the position vector r: dr v = (3.5) dt d = (xi + yj + zk) (3.6) dt dx dy dz = i + j + k (3.7) dt dt dt can be written: v = vxi + vyj + vzk (3.8) 51 52 CHAPTER 3. MOTION IN TWO AND THREE DIMENSIONS where dx dy dz v = v = v = (3.9) x dt y dt z dt The instantaneous velocity v of a particle is always tangent to the path of the particle. 3.1.3 Acceleration If a particle’s velocity changes by ∆v in a time period ∆t, the average acceleration a for that period is ∆v ∆v ∆v ∆v a = = x i + y j + z k (3.10) ∆t ∆t ∆t ∆t but a much more interesting quantity is the result of shrinking the period ∆t to zero, which gives us the instantaneous acceleration, a.
    [Show full text]
  • Rotational Motion of Electric Machines
    Rotational Motion of Electric Machines • An electric machine rotates about a fixed axis, called the shaft, so its rotation is restricted to one angular dimension. • Relative to a given end of the machine’s shaft, the direction of counterclockwise (CCW) rotation is often assumed to be positive. • Therefore, for rotation about a fixed shaft, all the concepts are scalars. 17 Angular Position, Velocity and Acceleration • Angular position – The angle at which an object is oriented, measured from some arbitrary reference point – Unit: rad or deg – Analogy of the linear concept • Angular acceleration =d/dt of distance along a line. – The rate of change in angular • Angular velocity =d/dt velocity with respect to time – The rate of change in angular – Unit: rad/s2 position with respect to time • and >0 if the rotation is CCW – Unit: rad/s or r/min (revolutions • >0 if the absolute angular per minute or rpm for short) velocity is increasing in the CCW – Analogy of the concept of direction or decreasing in the velocity on a straight line. CW direction 18 Moment of Inertia (or Inertia) • Inertia depends on the mass and shape of the object (unit: kgm2) • A complex shape can be broken up into 2 or more of simple shapes Definition Two useful formulas mL2 m J J() RRRR22 12 3 1212 m 22 JRR()12 2 19 Torque and Change in Speed • Torque is equal to the product of the force and the perpendicular distance between the axis of rotation and the point of application of the force. T=Fr (Nm) T=0 T T=Fr • Newton’s Law of Rotation: Describes the relationship between the total torque applied to an object and its resulting angular acceleration.
    [Show full text]
  • Exploring Robotics Joel Kammet Supplemental Notes on Gear Ratios
    CORC 3303 – Exploring Robotics Joel Kammet Supplemental notes on gear ratios, torque and speed Vocabulary SI (Système International d'Unités) – the metric system force torque axis moment arm acceleration gear ratio newton – Si unit of force meter – SI unit of distance newton-meter – SI unit of torque Torque Torque is a measure of the tendency of a force to rotate an object about some axis. A torque is meaningful only in relation to a particular axis, so we speak of the torque about the motor shaft, the torque about the axle, and so on. In order to produce torque, the force must act at some distance from the axis or pivot point. For example, a force applied at the end of a wrench handle to turn a nut around a screw located in the jaw at the other end of the wrench produces a torque about the screw. Similarly, a force applied at the circumference of a gear attached to an axle produces a torque about the axle. The perpendicular distance d from the line of force to the axis is called the moment arm. In the following diagram, the circle represents a gear of radius d. The dot in the center represents the axle (A). A force F is applied at the edge of the gear, tangentially. F d A Diagram 1 In this example, the radius of the gear is the moment arm. The force is acting along a tangent to the gear, so it is perpendicular to the radius. The amount of torque at A about the gear axle is defined as = F×d 1 We use the Greek letter Tau ( ) to represent torque.
    [Show full text]
  • Owner's Manual
    OWNER’S MANUAL GET TO KNOW YOUR SYSTEM 1-877-DRY-TIME 3 7 9 8 4 6 3 basementdoctor.com TABLE OF CONTENTS IMPORTANT INFORMATION 1 YOUR SYSTEM 2 WARRANTIES 2 TROUBLESHOOTING 6 ANNUAL MAINTENANCE 8 WHAT TO EXPECT 9 PROFESSIONAL DEHUMIDIFIER 9 ® I-BEAM/FORCE 10 ® POWER BRACES 11 DRY BASEMENT TIPS 12 REFERRAL PROGRAM 15 IMPORTANT INFORMATION Please read the following information: Please allow new concrete to cure (dry) completely before returning your carpet or any other object to the repaired areas. 1 This normally takes 4-6 weeks, depending on conditions and time of year. Curing time may vary. You may experience some minor hairline cracking and dampness 2 with your new concrete. This is normal and does not affect the functionality of your new system. When installing carpet over the new concrete, nailing tack strips 3 is not recommended. This may cause your concrete to crack or shatter. Use Contractor Grade Liquid Nails. It is the responsibility of the Homeowner to keep sump pump discharge lines and downspouts (if applicable) free of roof 4 materials and leaves. If these lines should become clogged with external material, The Basement Doctor® can repair them at an additional charge. If we applied Basement Doctor® Coating to your walls: • This should not be painted over unless the paint contains an anti-microbial for it is the make-up of the coating that prohibits 5 mold growth. • This product may not cover all previous colors on your wall. • It is OK to panel or drywall over the Basement Doctor® Coating.
    [Show full text]
  • Rotation: Moment of Inertia and Torque
    Rotation: Moment of Inertia and Torque Every time we push a door open or tighten a bolt using a wrench, we apply a force that results in a rotational motion about a fixed axis. Through experience we learn that where the force is applied and how the force is applied is just as important as how much force is applied when we want to make something rotate. This tutorial discusses the dynamics of an object rotating about a fixed axis and introduces the concepts of torque and moment of inertia. These concepts allows us to get a better understanding of why pushing a door towards its hinges is not very a very effective way to make it open, why using a longer wrench makes it easier to loosen a tight bolt, etc. This module begins by looking at the kinetic energy of rotation and by defining a quantity known as the moment of inertia which is the rotational analog of mass. Then it proceeds to discuss the quantity called torque which is the rotational analog of force and is the physical quantity that is required to changed an object's state of rotational motion. Moment of Inertia Kinetic Energy of Rotation Consider a rigid object rotating about a fixed axis at a certain angular velocity. Since every particle in the object is moving, every particle has kinetic energy. To find the total kinetic energy related to the rotation of the body, the sum of the kinetic energy of every particle due to the rotational motion is taken. The total kinetic energy can be expressed as ..
    [Show full text]
  • Circular Motion Angular Velocity
    PHY131H1F - Class 8 Quiz time… – Angular Notation: it’s all Today, finishing off Chapter 4: Greek to me! d • Circular Motion dt • Rotation θ is an angle, and the S.I. unit of angle is rad. The time derivative of θ is ω. What are the S.I. units of ω ? A. m/s2 B. rad / s C. N/m D. rad E. rad /s2 Last day I asked at the end of class: Quiz time… – Angular Notation: it’s all • You are driving North Highway Greek to me! d 427, on the smoothly curving part that will join to the Westbound 401. v dt Your speedometer is constant at 115 km/hr. Your steering wheel is The time derivative of ω is α. not rotating, but it is turned to the a What are the S.I. units of α ? left to follow the curve of the A. m/s2 highway. Are you accelerating? B. rad / s • ANSWER: YES! Any change in velocity, either C. N/m magnitude or speed, implies you are accelerating. D. rad • If so, in what direction? E. rad /s2 • ANSWER: West. If your speed is constant, acceleration is always perpendicular to the velocity, toward the centre of circular path. Circular Motion r = constant Angular Velocity s and θ both change as the particle moves s = “arc length” θ = “angular position” when θ is measured in radians when ω is measured in rad/s 1 Special case of circular motion: Uniform Circular Motion A carnival has a Ferris wheel where some seats are located halfway between the center Tangential velocity is and the outside rim.
    [Show full text]
  • Torque Speed Characteristics of a Blower Load
    Torque Speed Characteristics of a Blower Load 1 Introduction The speed dynamics of a motor is given by the following equation dω J = T (ω) − T (ω) dt e L The performance of the motor is thus dependent on the torque speed characteristics of the motor and the load. The steady state operating speed (ωe) is determined by the solution of the equation Tm(ωe) = Te(ωe) Most of the loads can be classified into the following 4 general categories. 1.1 Constant torque type load A constant torque load implies that the torque required to keep the load running is the same at all speeds. A good example is a drum-type hoist, where the torque required varies with the load on the hook, but not with the speed of hoisting. Figure 1: Connection diagram 1.2 Torque proportional to speed The characteristics of the charge imply that the torque required increases with the speed. This par- ticularly applies to helical positive displacement pumps where the torque increases linearly with the speed. 1 Figure 2: Connection diagram 1.3 Torque proportional to square of the speed (fan type load) Quadratic torque is the most common load type. Typical applications are centrifugal pumps and fans. The torque is quadratically, and the power is cubically proportional to the speed. Figure 3: Connection diagram 1.4 Torque inversely proportional to speed (const power type load) A constant power load is normal when material is being rolled and the diameter changes during rolling. The power is constant and the torque is inversely proportional to the speed.
    [Show full text]
  • Explanation for Terminology Maxon ECX
    Explanation for Terminology maxon ECX Dimensional drawings 14 Speed/torque gradient 29 Number of pole pairs Presentation of the views according to the projection n/M [rpm/mNm] Number of north poles of the permanent magnet. The method E (ISO). The speed/torque gradient is an indicator of the motor’s phase streams and commutation signals pass through All dimensions in [mm]. performance. The smaller the value, the more powerful per revolution p cycles. Servo-controllers require the cor - the motor and consequently the less motor speed varies rect details of the number of pole pairs. Motor Data with load variations. It is based on the quotient of ideal no The values in lines 2–15 are valid when using block com- load speed and ideal stall torque (tolerance ± 20%). 30 Number of phases mutation. With flat motors, the real gradient depends on speed: at All maxon EC motors have three phases. higher speeds, it is steeper, but flatter at lower speeds. 1 Nominal voltage U N [Volt] The real gradient at nominal voltage can be approxi- 31 Weight of motor [g] is the applied voltage between two powered phases in mated by a straight line between no load speed and the 32 Typical noise level [dBA] block commutation. See page 32 for the timing diagram nominal operating point (see page 45). of the voltage in the three phases. All nominal data (lines is that statistical average of the noise level measured according to maxon standard (10 cm distance radially 2–9) refer to this voltage. Lower and higher voltages are 15 Mechanical time constant m [ms] permissible, provided that limits are not exceeded.
    [Show full text]
  • High-Speed Ground Transportation Noise and Vibration Impact Assessment
    High-Speed Ground Transportation U.S. Department of Noise and Vibration Impact Assessment Transportation Federal Railroad Administration Office of Railroad Policy and Development Washington, DC 20590 Final Report DOT/FRA/ORD-12/15 September 2012 NOTICE This document is disseminated under the sponsorship of the Department of Transportation in the interest of information exchange. The United States Government assumes no liability for its contents or use thereof. Any opinions, findings and conclusions, or recommendations expressed in this material do not necessarily reflect the views or policies of the United States Government, nor does mention of trade names, commercial products, or organizations imply endorsement by the United States Government. The United States Government assumes no liability for the content or use of the material contained in this document. NOTICE The United States Government does not endorse products or manufacturers. Trade or manufacturers’ names appear herein solely because they are considered essential to the objective of this report. REPORT DOCUMENTATION PAGE Form Approved OMB No. 0704-0188 Public reporting burden for this collection of information is estimated to average 1 hour per response, including the time for reviewing instructions, searching existing data sources, gathering and maintaining the data needed, and completing and reviewing the collection of information. Send comments regarding this burden estimate or any other aspect of this collection of information, including suggestions for reducing this burden, to Washington Headquarters Services, Directorate for Information Operations and Reports, 1215 Jefferson Davis Highway, Suite 1204, Arlington, VA 22202-4302, and to the Office of Management and Budget, Paperwork Reduction Project (0704-0188), Washington, DC 20503.
    [Show full text]
  • Frame of Reference
    Frame of Reference Ineral frame of reference– • a reference frame with a constant speed • a reference frame that is not accelerang • If frame “A” has a constant speed with respect to an ineral frame “B”, then frame “A” is also an ineral frame of reference. Newton’s 3 laws of moon are valid in an ineral frame of reference. Example: We consider the earth or the “ground” as an ineral frame of reference. Observing from an object in moon with a constant speed (a = 0) is an ineral frame of reference A non‐ineral frame of reference is one that is accelerang and Newton’s laws of moon appear invalid unless ficous forces are used to describe the moon of objects observed in the non‐ineral reference frame. Example: If you are in an automobile when the brakes are abruptly applied, then you will feel pushed toward the front of the car. You may actually have to extend you arms to prevent yourself from going forward toward the dashboard. However, there is really no force pushing you forward. The car, since it is slowing down, is an accelerang, or non‐ineral, frame of reference, and the law of inera (Newton’s 1st law) no longer holds if we use this non‐ineral frame to judge your moon. An observer outside the car however, standing on the sidewalk, will easily understand that your moon is due to your inera…you connue your path of moon unl an opposing force (contact with the dashboard) stops you. No “fake force” is needed to explain why you connue to move forward as the car stops.
    [Show full text]