• Share
  • Email
  • Embed
  • Like
  • Save
  • Private Content
Maxon presentation  sizing of dc servo motors for extreme environment operation 02-2014
 

Maxon presentation sizing of dc servo motors for extreme environment operation 02-2014

on

  • 118 views

Maxon Motor Presentation

Maxon Motor Presentation

Statistics

Views

Total Views
118
Views on SlideShare
118
Embed Views
0

Actions

Likes
0
Downloads
1
Comments
0

0 Embeds 0

No embeds

Accessibility

Categories

Upload Details

Uploaded via as Adobe PDF

Usage Rights

© All Rights Reserved

Report content

Flagged as inappropriate Flag as inappropriate
Flag as inappropriate

Select your reason for flagging this presentation as inappropriate.

Cancel
  • Full Name Full Name Comment goes here.
    Are you sure you want to
    Your message goes here
    Processing…
Post Comment
Edit your comment

    Maxon presentation  sizing of dc servo motors for extreme environment operation 02-2014 Maxon presentation sizing of dc servo motors for extreme environment operation 02-2014 Document Transcript

    • Introduction drive seminar maxon seminar: Sizing of DC Servo Motors for Extreme Environment Operation  What are the challenges and what is required?  Performance of heavy duty drive systems © 2012 maxon motor ag, Sachseln, Switzerland Learning objectives The participants …  learn to read the data sheets of DC motors, EC motors, gearheads.  know the main properties and application ranges of DC and EC motors and be able to select the correct system.  know how the particular features of maxon heavy duty motors and gearheads can be used for extreme operation conditions. Page 1 © 2014, maxon motor ag Page 1
    • Introduction drive seminar Agenda Heavy Duty Seminar 09.30 – 10.15 Motor selection: What is it all about? – Application and situation analysis – Extracting key load parameters 10.15 – 10.45 Properties of brushed and brushless DC motors – Design variants – Commutation systems: brushed, brushless 10.45 – 11.00 Coffee break 11.00 – 11.30 Motor data sheets – Characteristic motor lines – Operation ranges 11.30 – 12.15 Heavy Duty motors and gearheads 12.15 – 13.00 Lunch 13.00 – 13.45 Motor selection example 13.45 – 14.30 Questions, discussion Media  maxon Formulae Handbook – epaper.maxonmotor.ch/formulaehandbook  maxon catalogue – epaper.maxonmotor.ch/en/  Presentation hand-outs  www.maxonmotor.com – Service & Downloads – Service Desk (FAQ) – maxon academy Page 2 © 2014, maxon motor ag Page 2
    • Overview of the selection steps drive seminar Selection of drive components  Systematics of the drive selection  Situation analysis, boundary conditions  How is the integration into the environment?  Preselection  Determining the load requirements  Result: key data for load characterization © 2012 maxon motor ag, Sachseln, Switzerland Systematic selection process Step 1 overview situation power communication ambient condition step 2 load step 3 drive step 4 gearhead Page step 5+6 step 7 motor type sensor winding controller 1 © 2013, maxon motor ag Page 1
    • Overview of the selection steps drive seminar Step 1: Gain an overview  analyze  recognize dependencies problem mechanics power operating mode motion profile control concept  checklist operating points control accuracy boundary conditions Drive system as a black box environment electrical power task  current  voltage  temperature, atmosphere  impacts, vibration … boundary conditions  dimensions  service life …  set values  commands emissions mechanical power quality, accuracy  resolution  mech. play     electro magnetic heat noise …  force, torque  velocity, speed Page 2 © 2013, maxon motor ag Page 2
    • Overview of the selection steps drive seminar Operating mode  What is a working cycle?  How often is it repeated? Which breaks?  continuous operation  cyclic operation  intermittent  Short-time operation Operating modes  continuous (S1) load time  short term (S2)  working cycles  intermittent (S3) Page 3 © 2013, maxon motor ag Page 3
    • Overview of the selection steps drive seminar Control concept  What kind of communication? – communication with higher level host system – set value range – inputs and outputs  Controlled variable – torque, current – speed, velocity – position feedback sensor  Controlled range, accuracy? – position resolution – speed stability Controller: Heart of the drive system Page 4 © 2013, maxon motor ag Page 4
    • Overview of the selection steps drive seminar Sensors in feedback systems Power Motion Controller Closed loop system for speed or position Commands, Set values Control parameter Feedback, sensor Position ∆𝑝𝑜𝑠 Speed, Direction ∆𝑡 Encoder  Hall sensors Resolver Speed, Direction DC Tacho  IxR Task and control accuracy  The accuracy of control is the combined result of all components in a drive system! – resolution, precision signal amplification command controller mechanical play motor gearhead, drive load control loop sensor Page 5 © 2013, maxon motor ag phase shifts time shifts Page 5
    • Overview of the selection steps drive seminar Accuracy of drive systems  position accuracy – – – – absolute, relative, repeatability overshoot allowed? mechanical play in couplings, gearheads, … encoder resolution and accuracy (linearity) r  speed accuracy – – – – Corrected in what time frame? t min. speed nmin by encoder resolution max. speed nmax by limiting frequency of the encoder Speed ​ripple by current and / or torque ripple  electronic components – resolution of A/D-converters, frequency voltage converter – bandwidth, temperature influences Time and frequency aspects Page 6 © 2013, maxon motor ag Page 6
    • Overview of the selection steps drive seminar Power flow power supply Losses controller gearhead, drive motor Pmech = v * F Pmech = ω * M sensor Pel = U * I load  energy is not stored: Power flow – Power: a „constant“ reference value of the drive system  Power consists of 2 components: – voltage and current – velocity and force or speed and torque – One components can only increase at the expense of the other. Transformation of power  transformation of power  efficiency η describes losses – electrical to electrical: η = 90 – 95% η = 90% – electrical to mechanical: optimum η = 80 - 90% – mechanical to mechanical: ball screw spindle η = 80 - 90% η = 90% per stage trapezoidal spindle 40% worm gear < 40% Page 7 © 2013, maxon motor ag Page 7
    • Overview of the selection steps drive seminar Mechanical drive concept  Drive design: linear – rotation  Drive elements and coupling with load  relative position of motor and load – e.g. bridge a distance with a belt Motors up to 500W n DC behavior (shunt) DC motors M I BLDC motors linear motors f stepper motors  Stator winding  magnetic rotor synchronous motors start M asynchronous motors Page 8 © 2013, maxon motor ag Page 8
    • Overview of the selection steps drive seminar Particular boundary conditions  dimensions  service life – specific depending on load cycle, ambient conditions and application – given as service hours or numbers of working cycles – limited by the weakest component  temperature, atmosphere – can influence the achievable power and service life  noise, vibration – specific depending on load cycle, mounting and ambient conditions, application – influences on service life Interfaces: Connections  electrical connections – cable type, cable length, colours – plug – strain relief  mechanical interface – mounting type, mounting pilot, threads, number and location of bolt holes – output shaft: length, diameter, flats – drive elements, pinions, couplings – tolerances Page 9 © 2013, maxon motor ag Page 9
    • Overview of the selection steps drive seminar Definition of the load requirements  motion profile and  forces and torques operation points v(t), F(t)  mass inertia and n(t), M(t)  Key values acceleration Operating points  Pair of – torque and speed – force and velocity  standard representation: (x,y) = (M,n) or (F,v) speed n velocity v deceleration acceleration torque M force F dwell Page 10 © 2013, maxon motor ag Page 10
    • Overview of the selection steps drive seminar Operating point and motion profile n 1 2 3 4 1 t n extreme operating point 2 3 4     1 M (M1,n1) acceleration friction and acceleration (M2,n2) const. speed friction only (M3,n3) deceleration friction helps during deceleration (M4,n4) dwell depending on friction Key load data for characterization  maximum load  average effective load (RMS) MRMS   1 2 2 t1M1  t 2M2  t 3M3  ... 2 t tot Fmax / Mmax F/M  FRMS / MRMS Δtmax Δttot  maximum velocity or speed vmax / nmax  duration of the maximum load  duration of a load cycle Δtmax Δttot  required position resolution  required speed accuracy t Δs Δn Page 11 © 2013, maxon motor ag Page 11
    • Overview of the selection steps drive seminar Example: Conveyor belt for samples  pulley diameter  maximum mass on belt  coefficient of friction on    100 mm 3 kg support friction force (empty belt) feed velocity supply voltage approx. 0.3 approx. 40 N 0.5 m/s 24 V Step 1: Situation Analysis What information is missing?  operating mode  current  task of the drive / setpoints  maximum length / diameter  service life  movement quality  emissions  environmental conditions  control concept Page  pulley diameter  maximum mass on belt  coefficient of friction on support 100 mm 3 kg approx. 0.3  friction force (empty belt) approx. 40N  feed velocity 0.5 m/s  supply voltage 24 V 12 © 2013, maxon motor ag Page 12
    • Overview of the selection steps drive seminar Step 2: Load requirements What information is missing?  acceleration value  motion profiles  Mass (rollers, conveyor belt)  Forces / torques  …….  pulley diameter  maximum mass on belt  coefficient of friction on support 100 mm 3 kg approx. 0.3  friction force (empty belt) approx. 40N  feed velocity 0.5 m/s  supply voltage 24 V Example: Conveyor belt for samples speed nL = 30 30 vL 30 0.5       100 min 1 d    0.05 2 feed force FL =   m  g  FR  0.3  3  10  40  9  40  50N torque ML = power PL = vL  FL  0.5  49  25 W acceleration Fa = m  d 0.1  FL   49  2.5Nm 2 2 vL 0.5  3   1.5N t 1 Page 13 © 2013, maxon motor ag Page 13
    • Overview of the selection steps drive seminar Example conveyor belt: Key values​​ Looking for a drive that can accomplish the following:  maximum speed  average torque  maximum torque  duration of Mmax nmax 100 rpm Meff approx. 2.5 Nm Mmax approx. 2.7 Nm 1s n 100 rpm 2.5 Page 2.7 Nm 14 © 2013, maxon motor ag M Page 14
    • maxon DC and EC motors drive seminar 3. Low power motors  DC motors  EC motors  Structure, properties, options © 2012, maxon motor ag, Sachseln, Switzerland Top DC motor designs conventional, slotted e.g. Dunkermotor coreless e.g. maxon DC motors - overview Top Page 1 © 2013, maxon motor ag Page 1
    • maxon DC and EC motors drive seminar Conventional DC motor el. connections winding brush system iron core commutator permanent magnet (external) flange housing (magn. return) DC motors - overview Top Coreless maxon DC motor (RE 35) self supporting winding commutator plate press ring shaft ball bearing brushes el. connections flange housing (magnetic return) ball bearing commutator permanent magnet (in the centre) press ring DC motors - overview Top Page 2 © 2013, maxon motor ag Page 2
    • maxon DC and EC motors drive seminar What makes maxon motors special?  no cogging – no soft magnetic teeth to interact with the permanent magnet – smooth motor running even at low speed – less vibrations and audible noise – any rotor position can easily be controlled – no nonlinearities in the control behavior  compact design – more efficient design of the magnetic circuit – compact magnet, high power density – small rotor mass inertia – high dynamics DC motors - overview Top What makes maxon motors special?  no iron core - no iron losses – constantly impressed magnetization – high efficiency, up to over 90% – low no-load current, typically < 50 mA  no saturation effects in the iron core – Even at the highest currents the produced torque is proportional to the motor current. – stronger magnets = stronger motors  low inductance – less brush fire, longer service life – less electromagnetic emissions – easier to suppress interferences: capacitor between connections, ferrite core at motor cable DC motors - overview Top Page 3 © 2013, maxon motor ag Page 3
    • maxon DC and EC motors drive seminar maxon DC motor families  DCX motor range – configurable system – high performance motor with NdFeB magnet – high torques and speeds  10 - 35mm  RE motor range  6 - 65mm – high performance motor with NdFeB magnet  A-max motor range – attractive price-performance ratio – DC motor with AlNiCo magnet  12 - 32mm  RE-max motor range  13 - 29mm – performance between RE and A-max DC motors - variants Top DC commutation systems Graphite  graphite brush with 50%     copper copper reduces the contact and brush resistance copper commutator graphite serves as lubricant spring system (schematic) Precious metal  bronze brush body with plated silver contact area  silver alloy commutator  smallest contact and brush resistance (50 mW)  CLL for high service life DC motors – commutation Top Page 4 © 2013, maxon motor ag Page 4
    • maxon DC and EC motors drive seminar DC commutation: Characteristics Graphite + well suited for high currents and Precious metal + well suited for smallest currents + + + peak currents well suited for start-stop and reversing operation larger motors (>approx. 10 W)  higher friction, higher no-load     current not suited for small currents higher audible noise higher electromagnetic emissions higher costs + + + + + and voltages well suited for continuous operation smaller motors very low friction low audible noise low electromagnetic interference cost effective  not suited for high current and  peak currents not suited for start-stop operation DC motors – commutation Top EC motors  electronic commutation – with Hall sensors – sensorless – sinusoidal commutation 2/4-pole EC motor internal rotor Multipole EC flat motor external rotor Multipole ECi motor internal rotor EC motors - overview Top Page 5 © 2013, maxon motor ag Page 5
    • maxon DC and EC motors drive seminar Brushless DC motor  names: EC motor, BLDC motor  motor behavior similar to DC motor – design similar to synchronous motor (3 phase stator winding, rotating magnet) – the powering of the 3 phases according to rotor position  main advantages: higher life, higher speeds  slotless windings: no magnetic detent, less vibrations  becomes more attractive – costs and size of electronics – strength of magnets EC motors - overview Top maxon EC motor families features in common EC motors - variants Top Page 6 © 2013, maxon motor ag Page 6
    • maxon DC and EC motors drive seminar maxon EC motor families  maxon EC motor – high speeds and torques  EC-max – good value for money – not optimized for performance: relatively high torque – speeds up to 12’000 min-1  EC-4pole – optimized for performance: high torque – speeds up to 25’000 min-1  EC flat motor – very good value for money – speeds up to 12’000 min-1 – relatively large amount of torque EC motors - variants Top maxon EC motor PCB with Hall sensors preloaded ball bearings magn. return: laminated iron stack control magnet housing el. connections winding and Hall sensors 3 phase knitted maxon winding balancing rings rotor (permanent magnet) EC motors - variants Top Page 7 © 2013, maxon motor ag Page 7
    • maxon DC and EC motors drive seminar Electronic commutations systems  common goal: applying the current to get the maximum torque  perpendicular magnetic field orientation of - rotor (permanent magnet) - and stator (winding)  knowledge of rotor position with respect to winding commutation type block sensorless DECS sine rotor position feedback Hall sensors ESCON encoder (+ HS) EPOS2 maxon controller families ESCON EPOS2 EPOS3 EtherCAT EC motors – electronic commutation Top Block commutation rotor position from Hall sensor signals north  control magnet south Hall sensor 1 0 0 0° EC-max and EC flat: Power magnet is probed directly 1 1 0 0 1 0 0 1 1 0 0 1 1 0 1 1 0 0 60° 120° 180° 240° 300° 360° rotation angle  EC motors – electronic commutation Top Page 8 © 2013, maxon motor ag Page 8
    • maxon DC and EC motors drive seminar Block commutation commutation electronics + power stage (MOSFET) EC motor (magnet, winding, sensor) commutation logics Phase 1 HS1 Phase 3 HS3 HS2 Phase 2 – rotor position feedback EC motors – electronic commutation Top DC and EC motor: Comparison EC motor + long life, high speeds DC motor + simple operation and  preloaded ball bearings control, even without electronics + no electronic parts in the motor  brush commutation system + no brush fire  iron losses in the   more cables  more expensive limits motor life  max. speed limited by magnetic return needs electronics to run  electronic parts in the commutation system motor (Hall Sensor) Comparison DC and EC Top Page 9 © 2013, maxon motor ag Page 9
    • maxon DC and EC motors drive seminar DC and EC motor: Comparison maxon motor family RE (DC) EC EC-max (20 … 100 Watt) EC-4pole EC-flat EC-i 50 000 min-1 10 W/cm3 25 000 min-1 5 W/cm3 2 mNm/cm3 10 ms 1 mNm/cm3 5 ms max. speed power density torque density mech. time (min-1) (W/cm3) (mNm/cm3) const. (ms) Comparison DC and EC Top Page 10 © 2013, maxon motor ag Page 10
    • maxon Motor Data and Operating Ranges drive seminar Motor data and operating ranges of maxon DC motors  Motor behaviour: speed-torque line, current  Motor data and operating ranges © 2012, maxon motor ag, Sachseln, Switzerland Top DC motor as an energy converter  electrical in mechanical energy Pel  U  I – speed constant – torque constant – speed-torque line Pmech   30 nM PJ  R  I2  applies to DC and EC motors – "EC" = "brushless DC" (BLDC) Overview Page 1 © 2013, maxon motor ag Page 1
    • maxon Motor Data and Operating Ranges drive seminar Characteristic motor data describe the motor design and general behaviour  independent of actual voltage or current  strongly winding dependent values (electromechanical) 10 Terminal resistance (phase to phase) R 11 Terminal inductance (phase to phase) L 12 Torque constant kM 13 Ω Speed constant kn mH mNm / A rpm / V  almost independent of winding (mechanical) 14 Speed / torque gradient Dn/DM 15 Mechanical time constant tm 16 Rotor mass inertia JMot rpm / mNm ms gcm2 Characteristics Different windings R  low resistance winding  thick wire, few turns  low rated voltage  high rated and starting  high resistance winding  thin wire, many turns  high rated voltage  low rated and starting  high specific speed  low specific torque (mNm/A)  low specific speed (min-1/V)  high specific torque (mNm/A) currents currents (min-1/V) Characteristics Page 2 © 2013, maxon motor ag Page 2
    • maxon Motor Data and Operating Ranges drive seminar Electromechanical constants  Torque constant kM – produced torque is proportional to motor current – unit: mNm / A  Speed constant kn – law of induction: changing flux in a conductor loop – mostly used for calculating no-load speeds n0 – unit: min-1 / V M  kM  I n  k n  Uind n0  k n  U  Correlation – kM and kn are inverse, but in different units – expressed in the units from catalog: kM  kn  30'000 mNm min 1  A V Characteristics Motor as an electrical circuit U + I _ R L EMF: induced voltage Uind (winding) resistance R EMF winding inductance L • voltage losses over L can be neglected in DC motors applied motor voltage U: U  L  I  R  I  EMF  R  I  Uind t  30'000 R   M n  kn  U    2   kM    Dn n  kn  U  M DM Uind  U  R  I n M  UR kn kM Characteristics Page 3 © 2013, maxon motor ag Page 3
    • maxon Motor Data and Operating Ranges drive seminar Speed-torque line speed n n  kn  U  Dn M DM U > UN n0 n0  k n  U Dn U = UN DM MH IA torque M current I Characteristics Speed-torque gradient by how much is the speed reduced Dn, if the output motor torque is enhanced by DM? Dn 30'000 n  R  i 2 DM   k M MiH speed n strong motor: M1, n1 n0 Dn • flat speed-torque line, small Dn/DM • not sensitive to load changes • e.g. strong magnet, bigger motor M2, n2 DM weak motor: • steep speed-torque line, high Dn/DM • sensitive to load changes • e.g. weak magnet, smaller motor MH torque M Characteristics Page 4 © 2013, maxon motor ag Page 4
    • maxon Motor Data and Operating Ranges drive seminar Winding series n numerous winding variants adjust at U constant  electrical input power (voltage, current of power supply) thick wire  mechanical output power (speed, torque) thin wire M speed-torque gradient  basically constant for the winding series  constant filling factor: a constant amount of copper fills the air gap Characteristics Values at nominal voltage describe the special working points:  at rated voltage UN  at rated current IN  No-load operating point n – resulting no-load speed n0 – resulting no-load current I0  rated working point – resulting rated speed nN – resulting rated torque MN  Motor at stall – resulting stall torque MH – resulting starting current IA M Values at nominal voltage Page 5 © 2013, maxon motor ag Page 5
    • maxon Motor Data and Operating Ranges drive seminar Thermal motor data plastic plate describe the motor heating and thermal limits  depend strongly on mounting conditions  standard mounting: horizontal mounting  heating and cooling – thermal resistance housing-ambient Rth2 – thermal resistance winding-housing Rth1 – thermal time constant of winding tthW free convection at 25 °C ambient temperature – thermal time constant of motor tthS  temperature limits – ambient temperature range – max. winding temperature Tmax Specifications Mechanical motor data describe maximum speed and the properties of bearings  max. permissible speed – limited by bearing life considerations (EC) – limited by relative speed between collector and brushes (DC)  axial and radial play – suppressed by a preload  axial and radial bearing load F5 – dynamic: in operation – static: at stall axial press fit force (shaft supported) l Fd d Specifications Page 6 © 2013, maxon motor ag Page 6
    • maxon Motor Data and Operating Ranges drive seminar maxon standard tolerances  Sources – winding resistance – magnetic properties – friction and losses n ±7% ±8%  Results 1.1 1.0 0.9 – general tolerance level – tolerance in no-load current – tolerance in no-load speed  weaker magnet =>  stronger magnet => 0.86 1.0 1.16 5 to 10 % ± 50 % ± 10 % enhanced n0 reduced n0 M Values at nominal voltage Influence of temperature temperature coefficients Cu AlNiCo - 0.02 % per K Ferrite - 0.2 % per K NdFeB temperature + 0.39 % per K - 0.1 % per K resistance magnetic properties R: + 19.5 % kn + 5 % (no-load speed)  example: RE motor DT = + 50K kM - 5 % (more current!) stall torque MH : - 22 % Values at nominal voltage Page 7 © 2013, maxon motor ag Page 7
    • maxon Motor Data and Operating Ranges drive seminar Motor limits: operation ranges Speed n nmax continuous operation - higher ambient temperature - heat accumulation short term operation torque M current I MN IN - lower ambient temperature - good heat dissipation Operating Range Short-term operation overload  motor may be overloaded for a short time and repeatedly – limit: max. permissible winding temperature – depends on thermal time constant of winding tW and amount of overload overload duration 5tW 4tW 3tW 2tW continous operation 1tW thermally prohibitted short term operation permissible short term operation torque M load MN 2MN 3MN 4MN Operating Range Page 8 © 2013, maxon motor ag Page 8
    • Examples for motor and drive selection drive seminar Examples for motor and drive selection  Continuous operation  Cyclic operation  maxon selection program © 2012 maxon motor ag, Sachseln, Switzerland Systematic selection process Step 1 overview situation power communication ambient condition step 2 load step 3 drive step 4 gearhead Page step 5+6 step 7 motor type sensor winding controller 1 © 2013, maxon motor ag Page 1
    • Examples for motor and drive selection drive seminar Step 5: Motor selection conveyor belt  selecting the motor type  selection of the winding  planetary Gearhead GP 32 A – reduction 51:1  Motor requirements (key values) – Speed 5100 min-1 – average torque 70 mNm – maximum torque about 75 mNm, 1s Selection criteria motor type Commutation (Service life) Sensor Shaft Bearing (Service life) Electrical connection Ambient condition Page 2 © 2013, maxon motor ag Page 2
    • Examples for motor and drive selection drive seminar Motor type selection  Combination with maxon Modular System + motor   A-max 32 RE-max 29 (continuous torque) max. torque max. permissible speed RE 35, 90W A-max 26  Nominal torque RE 30, 60W RE 25, 20W n + motor RE 25, 10W selected gearhead EC 32, 80W MRMS  MN continuous operation nmax short term operation deceleration acceleration MN M Motor type selection according maxon modular system motor type MN suited? RE 25 < 30 mNm too weak A-max 26 < 18 mNm too weak RE-max 29 < 30 mNm too weak RE 30 ca. 80 mNm RE 35 100 mNm strong EC 32 < 45 mNm too weak A-max 32 < 45 mNm too weak EC 32 flat < 10 mNm too weak Page 3 © 2013, maxon motor ag good Page 3
    • Examples for motor and drive selection drive seminar Step 6: Winding selection  Goal: Reach the required speed at maximum possible motor voltage under maximum load  for a given motor size (motor type) this means: sufficiently high speed constant n0,theor nmot n Mmot M n0,theor  nmot  speed n n k n  k n,theor  0,theor Umot nmot, Mmot speed-torque line high enough for the required load speed speed-torque line too low for the required load speed torque M Mmot Example: Conveyor belt for samples n n Mmot  5100  9  70  5700 min 1 M n 5700 rpm k n  k n,theor  0,theor   270 Umot 21 V n0,theor  nmot  [rpm] 5700 5100  select motor 310007: – speed constant kn = 369 min-1/V  needed current – with torque constant kM Imax  70 mNm M  Page Mmax  I0 kM 70  0.15  2.8 A 25.9 4 © 2013, maxon motor ag Page 4
    • Feedback and Motion Control maxon drive seminar Feedback and Motion Control  Feedback systems – Specifically: Encoder  Properties of controllers – control value – performance, motor type – communication, signal processing © 2012 maxon motor ag, Sachseln, Switzerland Motion Control System Overview Power Supply CAN Motion Controller I/O Supervisor / Master (PLC / PC) v(t), F(t) Motor Gearhead Encoder Load Page 1 © 2013, maxon motor ag Page 1
    • Feedback and Motion Control maxon drive seminar Sensors in feedback systems Power Motion Controller Closed loop system for speed or position Commands, Set values Control parameter Position ∆𝑝𝑜𝑠 ∆𝑡 Speed, Direction Speed, Direction Feedback, sensor Encoder  Hall sensors Resolver DC Tacho  IxR Drive component: Controller Page 2 © 2013, maxon motor ag Page 2
    • Feedback and Motion Control maxon drive seminar mmc product families controller family EPOS ESCON current control control loops speed control position control system architecture commanded by master system setup feedback sensors commanded by digital and analog inputs graphical user interface (Studios) needed feedback: • EC: encoder and Hall sensor • DC: encoder possible feedback: • encoder • Hall sensor (EC) • DC tacho (DC) Configuration – EPOS/ESCON Studio Communication  Bus types  Baud rates  … Motor type  DC  BLDC  Commutation Feedback type  Encoder (resolution)  Hall sensor  DC Tacho Configuration Graphical User Interface (GUI) Inputs / Outputs  Stop  Direction  Enable - disable Operation mode  Current control  Speed control  Position control  Ready  Speed comparator  …. Page 3 © 2013, maxon motor ag Page 3
    • Selection example – step by step Drive seminar Selection of drive components  The systematics of the drive selection on a practical application example © 2013 maxon motor ag, Sachseln, Switzerland Page 1 © 2013, maxon motor ag Page 1
    • Selection example – step by step Drive seminar Step 1: Situation Analysis Step 1 overview situation power communication ambient condition step 2 load step 3 drive step 4 gearhead step 5+6 step 7 motor type sensor winding controller What information is missing?  operating mode, motion profile – acceleration – inertias (rollers, belt)  current power supply  control concept, variable – set value – movement quality Given:  pulley diameter  maximum mass on belt  coefficient of friction on support  friction force (empty belt)  feed velocity  supply voltage  maximum length / diameter  service life  environmental conditions – emissions Page 2 © 2013, maxon motor ag 100 mm 15 kg approx. 0.2 approx. 30 N 0.5 m/s 24 V Page 2
    • Selection example – step by step Drive seminar Step 2: Load Requirements Step 1 overview situation power communication ambient condition step 2 load step 3 drive step 4 gearhead step 5+6 step 7 motor type sensor winding controller Conveyor belt: load data  Maximum load speed 𝑣 𝐿 = 0.5 𝑚 𝑠  feed force 𝐹𝐿 = 𝐹 𝑅 +  acceleration 𝜇 ∙ 𝑚 ∙ 𝑔 = 30 + 0.2 ∙ 15 ∙ 9.8 ≅ 60𝑁 𝐹𝑎 = 𝑚 ∙ ∆𝑣 𝐿 0.5 = 15 ∙ = 15𝑁 ∆𝑡 0.5  power 𝑃 𝐿 = 𝑣 𝐿 ∙ 𝐹 𝐿 = 0.5 ∙ 60 = 30𝑊 Page 3 © 2013, maxon motor ag Page 3
    • Selection example – step by step Drive seminar Conveyor belt: Key values ​load Looking for a drive that can accomplish the following:  maximum velocity  average force  maximum force  duration of Fmax vmax = 0.5 m/s Feff = approx. 60 N Fmax = approx. 80 N Δtmax = 0.5 s v 0.5 m/s 60 N 80 N F Step 3: Drive Step 1 overview situation power communication ambient condition step 2 load step 3 drive step 4 gearhead Page step 5+6 step 7 motor type sensor winding controller 4 © 2013, maxon motor ag Page 4
    • Selection example – step by step Drive seminar Conveyor belt: load data gear  maximum speed  average torque  maximum torque 𝑛 𝐺 = 30 ∙ 𝜔 = 30 ∙ 𝜋 𝜋 𝑣𝐿 𝑑 2 = 30 ∙ 𝜋 0.5 ≅ 100𝑟𝑝𝑚 0.05 𝑑 0.1 ∙ 𝐹𝐿 = ∙ 60 = 3.0𝑁𝑚 2 2 𝑑 0.1 = ∙ 𝐹 𝑚𝑎𝑥 = ∙ 80 = 4.0𝑁𝑚 2 2 𝑀 𝐺,𝑒𝑓𝑓 = 𝑀 𝐺,𝑚𝑎𝑥 Example conveyor belt: Key values Looking for a drive that can accomplish the following:  maximum speed  average torque  maximum torque  duration of Mmax nG,max = 100 rpm MG,eff = approx. 3.0 Nm MG,max = approx. 4.0 Nm Δtmax = 0.5 s 3.0 4.0 Nm Page 5 n 100 rpm © 2013, maxon motor ag M Page 5
    • Selection example – step by step Drive seminar Step 4: Gearhead selection Step 1 overview situation power communication ambient condition step 2 load step 3 drive step 4 gearhead step 5+6 step 7 motor type sensor winding controller Step 4: Gearhead selection Looking for a drive that can accomplish the following:  maximum speed  average torque  maximum torque  duration of Mmax nG,max = 100 rpm MG,eff = approx. 3.0 Nm MG,max = approx. 4.0 Nm Δtmax = 0.5 s ? Page 6 © 2013, maxon motor ag Page 6
    • Selection example – step by step Drive seminar Limits gear selection torque MN > MG,eff output speed n Reduction out of input and output speeds: 𝑖< nmax,L 𝑛 𝑚𝑎𝑥,𝑖𝑛 𝑛 𝑚𝑎𝑥,𝐿 nmax,in continuous operation nmax,L short term operation MN Mmax output torque M Selection Guide maxon Gear 3 Nm Page 7 © 2013, maxon motor ag Page 7
    • Selection example – step by step Drive seminar Conveyor belt: Gearhead selection  planetary gearhead – continuous torque – max. input speed – max. reduction – selected reduction – efficiency ηG GP 32 C 3 Nm (at least 2 stages) 8000 rpm 𝑛 𝑚𝑎𝑥,𝑖𝑛 8000 = = 80: 1 𝑛 𝑚𝑎𝑥,𝐿 100 𝑖< 79:1 70 %  requirements motor (key values) – speed 𝑛 – torque 𝑀 𝑚𝑜𝑡 = 𝑚𝑜𝑡 = 𝑛 𝐺 ∙ 𝑖 = 100 ∙ 79 = 7900 𝑟𝑝𝑚 𝑀𝐺 3.0 = = 54 𝑚𝑁𝑚 𝑖 ∙ 𝜂 𝐺 79 ∙ 70% Conveyor belt: Key values motor Looking for a motor that can accomplish the following:  maximum speed  average torque  maximum torque  duration of Mmax nmax = 7900 rpm Meff = 54 mNm Mmax = 72 mNm Δtmax = 0.5 s n 7900 rpm 54 72 mNm Page 8 © 2013, maxon motor ag M Page 8
    • Selection example – step by step Drive seminar Step 5+6: Selection motortyp & winding Step 1 overview situation power communication ambient condition step 2 load step 3 drive step 4 gearhead step 5+6 step 7 motor type sensor winding controller Step 5: Motor type selection Motor type according to modular system RE 25 RE 30 Nominal torque MN > 54 mNm RE 35 A-max 26 A-max 32 RE-max 29 EC 32 EC-max 22, 25W max. permissible speed > 7900 rpm continuous operation short term operation EC-max 30, 40W EC-4pole 22 EC flat 32 EC-i 40 MN Page 9 © 2013, maxon motor ag M Page 9
    • Selection example – step by step Drive seminar Further selection criteria motor type Commutation (Service life) Sensor Shaft Bearing (Service life) Electrical connection Ambient condition Conveyor belt motor type Motor type according Nominal to modular system torque MN suitability RE 25 < 30 mNm Too weak, with brushes RE 30 ca. 90 mNm OK, but with brushes RE 35 ca. 100 mNm strong, but with brushes A-max 26 < 18 mNm too weak, with brushes A-max 32 < 45 mNm too weak, with brushes, nmax= 6000 rpm RE-max 29 < 30 mNm too weak, with brushes EC 32 < 45 mNm too weak EC-max 22, 25W < 23 mNm too weak EC-max 30, 40W < 34 mNm too weak, (60W version => 63 mNm) EC-4pole 22 < 64 mNm OK, only 120W version, builds long EC flat 32 < 23 mNm too weak EC-i 40 < 70 mNm OK Page 10 © 2013, maxon motor ag Page 10
    • Selection example – step by step Drive seminar Step 6: Winding selection  Goal: Reach the required speed at maximum possible motor voltage under maximum load  for a given motor size (motor type) this means: sufficiently high speed constant ∆𝑛 ∙ 𝑀 𝑚𝑎𝑥 ∆𝑀 𝑛0,𝑡ℎ𝑒𝑜𝑟 𝑘 𝑛 > 𝑘 𝑛,𝑡ℎ𝑒𝑜𝑟 = 𝑈 𝑚𝑜𝑡 speed n 𝑛0,𝑡ℎ𝑒𝑜𝑟 = 𝑛 n0,theor nmot, Mmot nmot 𝑚𝑜𝑡 + speed-torque line high enough for the required load speed speed-torque line too low for the required load speed torque M Mmot Example: Conveyor belt for samples n ∆𝑛 ∙ 𝑀 𝑚𝑎𝑥 = 7900 + 17 ∙ 72 ≅ 9100 ∆𝑀 𝑛0,𝑡ℎ𝑒𝑜𝑟 9100 𝑚𝑖𝑛−1 𝑘 𝑛 > 𝑘 𝑛,𝑡ℎ𝑒𝑜𝑟 = = = 415 𝑈 𝑚𝑜𝑡 22 𝑉 𝑛0,𝑡ℎ𝑒𝑜𝑟 = 𝑛 [rpm] 9100 𝑚𝑜𝑡 + 7900  select motor 311537: – speed constant kn = 497 rpm/V  needed current – with torque constant kM 𝐼 𝑚𝑎𝑥 = 72 mNm M = Page 𝑀 𝑚𝑎𝑥 + 𝐼0 𝑘𝑀 72 + 0.166 = 3.9 A 19.2 11 © 2013, maxon motor ag Page 11
    • Selection example – step by step Drive seminar Step 7: Sensor and controller Step 1 overview situation power communication ambient condition step 2 load step 3 drive step 4 gearhead Page step 5+6 step 7 motor type sensor winding controller 12 © 2013, maxon motor ag Page 12