ECE5320 Mechatronics Assignment#01: Literature Survey on Sensors and ActuatorsOutlineWorking PrincipleSlide 4Slide 5Rotary vs. Linear MotorsAdvantages of Linear MotorsAdvantages of Linear Motors (Cont)Slide 9Disadvantages of Linear MotorsCommon Linear Motor TypesSlide 12Limitations of Common Linear Motor TypesPermanent Magnet Linear MotorX-Y Robotic Arm; PM Linear ApplicationPlatenPlaten (cont)Platen Motor ApplicationsLinear Induction Motor (LIM)Linear Induction Motor Application 1Linear Induction Motor Application 2U-Channel Linear MotorTubular Linear MotorMotor SelectionMotor SizingWhere to BuyTo explore furtherReference listThe EndLinear Motor IntroductionECE5320 MechatronicsAssignment#01: Literature Survey on Sensors and Actuators Assignment#01: Literature Survey on Sensors and Actuators Prepared by: William BourgeousDept. of Electrical and Computer Engineering Utah State UniversityE-mail: [email protected]: (435) 750-0147 Linear Motor IntroductionLinear Motor IntroductionSlide-2Outline Basic working principle illustratedMajor specificationsLimitationsLinear Motor TypesMajor applicationsSelection and Purchasing To probe furtherReference listLinear Motor IntroductionSlide-3Working PrincipleA basic linear motor can be envisioned as a conventional rotary motor slit axially and rolled out flat. Courtesy of: Sinker DescriptionLinear Motor IntroductionSlide-4Working PrincipleThe force (F = I L x B) on the moving charges in the purple bar magnet cause it to move to the right. Applying this principle we can build a linear motor.Courtesy of: sjsuLinear Motor IntroductionSlide-5Working PrincipleLinear Motors are typically composed of:1. Stationary magnets or planten (rotor); 2. Moving coil assembly - a specific arrangement of permanent magnets and/or electro-magnetsCourtesy of: Rockwell AutomationLinear Motor IntroductionSlide-6Rotary vs. Linear MotorsCourtesy of: Copley Motion SytemsLinear Motor IntroductionSlide-7Advantages of Linear Motors#1 advantage of linear motors:Totally eliminates the need, cost and limitations of mechanical rotation-to-translation mechanisms such as racks and pinions or belts and pulleys which are sources of elasticity and backlash. The complexity of the mechanical system is drastically reduced Courtesy of: BaldorLinear Motor IntroductionSlide-8Advantages of Linear Motors (Cont)•High repeatability – resolution to (0.1 microns) – this makes sure all parts produced are accurate and identical •Highly accurate – (2.5 micron/300 mm) – provides precise machine operation for precision parts•Faster acceleration – from 1 to over 10 G’s – this leads to shortened cycle times and improved productivity•Higher velocities – speeds to over 300 inches/second (8 meters/sec) – to position the payload fasterCourtesy of: BaldorLinear Motor IntroductionSlide-9Advantages of Linear Motors (Cont)•Long term reliability – only two parts with only one moving part – this leads to simplicity and improves the applications reliability•No wear or maintenance – no contacting parts, thus reducing component friction and wear•Ease of installation – linear motors are designed to allow for alignment tolerances. Misalignment produces no degradation of performance Courtesy of: BaldorLinear Motor IntroductionSlide-10Disadvantages of Linear Motors•Costly to purchase and install•Requires Higher Bandwidth in Sensors, Controls and Drives•Force Per Package Size: Linear motors are not compact force generators compared to a rotary motor. Linear motors are not brute force devices.•Heating: The forcer is often attached to the load. If an application is sensitive to heat, thermal management techniques need to be applied. Air and water cooling options are popular and common.•“No” Friction: For example, a linear motor is traveling at high speed and loses power. Without resistance in the system, it does not take long before the motor reaches the end of the stroke and slams the mechanical stops.Courtesy of: CompumotorLinear Motor IntroductionSlide-11Common Linear Motor Types•Linear motors can be classified by power supply, operation and control just as rotary motors are: •There are a wide variety of linear motors so we will classify them by mechanical construction.•Permanent Magnets•Electromagnets•Hybrid•Planten•DC•AC•Stepper•ServoLinear Motor IntroductionSlide-12Common Linear Motor Types•Permanent Magnet Motors •Platen Type Linear Motors •Linear Induction Motors •U shaped Linear Brushless Motors •TubularCourtesy of: Copley Motion SystemsLinear Motor IntroductionSlide-13Limitations of Common Linear Motor Types• Permanent Magnet (PM) Motors Limited forces/speeds •Platen Type Linear Motors Precision air gap required Exposed track •Linear Induction Motors Large physical size High power consumption Cooling typically required •U shaped Linear Brushless Motors Restricted heat dissipation •Tubular Linear Motors Limited travel; ends must be supported Courtesy of: Copley Motion SystemsLinear Motor IntroductionSlide-14Permanent Magnet Linear Motor•The same magnetic principles that apply to rotary PM motors hold true for linear PM motors (Figures A&B).Figure A – Electromagnetic Principles Figure B – PM Linear MotorCourtesy of: Rockwell AutomationLinear Motor IntroductionSlide-15X-Y Robotic Arm; PM Linear ApplicationCourtesy of: Idaho National LaboratoryCable ManagementPermanent MagnetsLinear Motor IntroductionSlide-16Platen•The electromagnets are formed in the shape of teeth so that their magnetic flux can be concentrated. •Only one set of teeth is aligned with the teeth on the platen at any time. Courtesy of: CompumotorLinear Motor IntroductionSlide-17Platen (cont)•When a pattern of energizing one coil and then another is established, the resulting magnetic field will pull the motor in one direction from one tooth to the next. When current flow to the coil is stopped, the forcer will align itself to the appropriate tooth set and create a holding force that tends to keep the forcer from moving left or right to another tooth. Courtesy of: CompumotorLinear Motor IntroductionSlide-18Platen Motor Applications•Accurate Position ApplicationsCourtesy of: National InstrumentsLinear Motor IntroductionSlide-19Linear Induction Motor (LIM)•The Linear Induction Motor (LIM) is designed for high force, long-stroke applications, such as material handling and people
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