maxon motor: selection of controllers and integrated...

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maxon motor:

Selection of controllers

and integrated systems

© 2017 maxon motor ag maxon_Control-System-Selection, WJ, Animated Version V2.31

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Criteria to find the base drive controller family

Base criteria 1: Control functionality?

Control Issues

Position?

Speed?

Torque?

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Base criteria 1: Control functionality?

Path

Generator

Speed

Control

Current

Control

Driver, Power

Amplifier

Actual

Current Actual

Value

Set Value

Current

Set Value

Pos

t

Digital

Command

4Q

Feedback

Motion / Positioning Controller

Path generator + Position control

Servo controller

4Q power stage

Processing sensor signals

Speed & Current control Speed Ramp

/Position

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Base criteria 1: Control functionality depending on application

Current or Torque control, e.g. in case of …

… a demand for a fixed or adjustable motor torque.

… an electrical screwdriver, pressing tool, strapping tool, …

Speed control, e.g. in case of …

… a demand for a fixed or adjustable speed (independent of load).

… a fan, drill, pump, centrifuge, conveyor belt, scanner, …

Position control, e.g. in case of …

… any precise angular or linear movement to a defined position.

… an X/Y table, turntable, robot, pick-and-place device, door drive, …

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Base criteria 2: Type of commanding

Commanding by analog or digital signals

– Standalone operation or commanding by I/O signals (e.g. PLC, C)

– Analog and digital I/Os with configurable functionality.

Commanding by a bus or serial interface

– Master controller, e.g. PLC, PC, Raspberry Pi, BeagleBone, C, …)

– USB, RS232, CAN, EtherCAT, or ??? interface.

Commanding by a fast, predictable, cyclic data exchange

– Real time master controller is mandatory!

– CAN, EtherCAT, or ??? Interface.


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Your notes

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maxon motor control: Base product lines 2017

DEC Module ESCON EPOS2 / EPOS4 MAXPOS

Controller 1-Q speed

controller

4-Q current / speed

controller

4-Q motion

controller

Highly dynamic 4-Q

motion controller

Control task

• Speed (open loop)

• Speed (closed loop)

• Current controller

• Speed (open loop)




• Positioning controller



• Positioning controller

Commanding Analog and

digital signals

Analog and

digital signals

typically with MASTER

and bus communcition

e.g. PLC, PC, C

EtherCAT-MASTER

mandatory

(e.g. PLC, RTOS)

Remark • High-volume projects

• Configuration

by input signals

• Flexible configuration

by USB and PC

software tool

• Housed, open frame,

module versions

• Base for customized

controllers

• USB, RS232, CAN

+ EtherCAT (EPOS4)

• PC software tool

for configuration

• Windows & Linux Libraries

for PC, Raspberry Pi,

BeagleBone

• EtherCAT only

• Ethernet, USB for

configuration only

• PC software tool

for configuration

EPOS4 only

(optional)

EPOS2 / EPOS4

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Selection based on application requirements

End user device DEC ESCON EPOS2/EPOS4 MAXPOS

Screw driver, Drill,

Pressing or strapping tool,

…

Fan, Pump,

Roller blind, …

Conveyor belt,

Centrifuge, Scanner, …

Open/Close - Door drive,

On/Off - Valve, …

X/Y table, turntable,

Valve, Door drive, …

Robot, Pick-and-Place,

Multi-axis position control

& drive synchronization, …

1st choice 1st choice 1st choice

( ) 1st choice 1st choice ( )

( ) 1st choice

1st choice ( ) Bus

commanding ( ) 1st choice

Bus

commanding

RS232

1Q 4Q 4Q 4Q

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Criteria to find the right product type

Additional criteria: Size, mounting, system integration

Modules

– "Motion Control" plug-in for integration in an electronic design.

– Additional electronics development (e.g. motherboard) required.

– Typically in use for medium and high volume applications.

– Space-saving, most compact in size.

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Compact / Open Frame

– Compact size with integrated connectors for all signals.

– Easy to mount close to the motor or in an electrical cabinet.

– For single piece applications, small and medium volume demand.

– Ready to use with optional cables.

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Housed

– Electronic board covered by a robust metal housing.

– Different kinds of mounting.

– Typically in use in an electrical cabinet or mounted on a machine.

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Integrated

– Motor and electronics integrated in one housing

– Catalog products + customized solutions

maxon EC-flat i.E.

with integrated speed control

maxon MCD

with integrated

positioning control

Customized solutions

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Additional criteria?

Supply

– Supply voltage

– Type of power supply ( Capability to handle reversed energy?)

Special environmental conditions

– Operating temperature range ( Derating of technical data?)

– Humidity ( Coated electronics?)

– Vibration ( Mounting, components in use?)

– Pressure ( Components in use?)

– Special standards (Aerospace, Medical, Military, Subsea, …)

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The solution triangle

Solution

Inhouse Experience

or Add-on Engineering Motion Control?

Programming?

System/Control Design?

System Environment

Power & size constraints?

Master or Standalone?

Commanding: I/O or bus?

Data Exchange: real-time?

Application's

Requirements Control Issues

Position

Velocity

Torque

Commercial Issues

Target price

Quantity / year

Market share

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Special demands?

Customized solution instead of a catalog product?

Commercial aspect -> Fully cost-optimized

– High-volume demand.

– Cost-optimization by getting rid of all components / connectors not needed.

– Special connectors adapted to existing cables for cost-optimized assembly.

Special PCB design

– Controller's PCB has to fit into a given space

(e.g. special PCB for a hand tool, …)

Add-on hardware features

– Controller has to integrate additional components

(e.g. LCD, brake chopper, …)

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Special demands: Modification / Customization

Increasing level of effort (period of time + costs)

Modification HW-

Components

Firmware

typ.

1 … 5 days

of work

Low-cost,

high volume

control design

Integration of

motor and control Customization

New design

based on another

mmc product

typ. 1 … 6 months

of work

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Modification business

Modification = Limited adaptations to catalog products

Enhanced functionality for special applications:

– Preconfiguration

– Modified firmware features

– PCB coating

– Reduced current limits

Typically a total effort of 1 - 5 days for

development, testing, and update of documents.

The resulting product (very often) looks

the same like the catalog product

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Customization business

Customization = Development of a fully tailor-made product

Individual electronics designs

for creative ideas!

Enhanced, new features

to fit special requirements!

Cost-optimized solutions

for high-volume series products!

High effort for specification, development,

test, and documentation, typ. 3 … 6 months

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Steps to go for a fully customized product

Everybody seems

to "know" what

is expected

Hidden tasks

& challenges

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End user: Let us automate the door!

The required features

look quite simple.

The solution also has to

be quite simple from the

user's point of view.

© 2

0th

Centu

ry Fox

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Obvious requirements of the end user

Press button "Open"

– Open the two parts of the door simultaneously.

Press button "Close"

– Close the two parts of the door simultaneously.

Any button for "Stop" or automatic "Stop"?

– e.g. in case of something going wrong.

Special points to take care about

– All movement should be smooth with less noise

– Make sure nobody is injured by the movement

– "Best possible price"

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The engineer's first focus: Technical data

Required technical details / data

– Speed, Torque, Load, Inertia

– Cycle times

– Mechanical dimensions

– Protection levels

© 2

0th

Centu

ry F

ox

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The engineer: System requirements?

Functional requirements

– Open / close the doors of an elevator.

– What has to happen when?

(Even in case of an error state or malfunction.)

– What safety level and standards have to be fulfilled?

System design

– Usability

– Service handling and future service costs

– Lifetime expectations & operational availability

– Integration in the system environment

– Commercial aspects (e.g. "Best price / feature ratio") © 2

0th

Centu

ry F

ox

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Customization -> The "hidden" challenges

Comprehensive engineering tasks

– Mechanical engineering

– Electronics hardware development

– Firmware development

(Add-on features, customized protocols, …)

– Verification of required standards

– Test of module & complete system

– Project management & Documentation

Specification, Design concepts, Implementation, Verification

Rule of thumb:

At least 30% of the effort is project management, testing, and documentation.

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Customization = Engineering business

Process steps to go through:

Require-

ments

Analysis

Feasi-

bility

Study

Design

Imple-

men-

tation

Inte-

gration

Verifi-

cation

Aim:

Get a common

and identical

understanding

of the

requirements.

Artifact:

Requirements

specification

Aim:

Evaluation

and checking

concepts,

feasibility, risk,

and effort.

Artifact:

Design

specification

Aim:

Hardware,

firmware, and

mechanical

engineering.

Artifacts:

HW-/FW-

architecture

documentation

Aim:

Hardware,

firmware, and

mechanical

development.

Artifacts:

Schematics,

layouts,

source code

Aim:

Putting

everything

together to

one system.

Artifacts:

User manual,

test plan

Aim:

Testing and

finalization of

documentation.

Artifacts:

Final product

specification,

test report

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maxon motors and controllers

set the world into motion

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The complete solution?!

System design.

Get an overall

system view.

Looking beyond

one's own nose.

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System design & components

E Motor G

Actuators

Sensors

Power

Supply

#n

#2

Motion

Controller

#1

Master

(Process)

Controller Bus communication

(Real time?) data exchange

HMI:

Human Machine

Interface

Data

base

Worldwide

network

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Understanding system levels & interfaces

Drive

Controller

System

Controller

Integration level:

Machine, Device, Hand tool, …

customer

Communication

Interface

Application

Software

User

Interface

Electromechanical

Drive unit

Signal &

Power lines

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2 3

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Level 1 + 2:

Drive

Engineering

Level 3 + 4:

System &

User Interface

Engineering

Focus on

application demands!

Understand the expectations

of the end user.

Get an overall system view.

Take functional, non-functional,

and technical data into account!

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Thinking further …

A drive system consists not only of a controller,

hence…

What are the requirements for the master and

the bus system?

What to consider when selecting the motor?

The sensor must be crucial for the position accuracy,

isn’t it?

Where are the traps and hidden dependencies?

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Thinking further ….

System performance

Rule of thumb

– Higher level controller can be 10 times slower

Requirement for bus performance

– Current control sampling rate = 100 kHz

=> commanding with 0.1 ms sampling is reasonable

– Speed / position controller = 10 kHz

=> commanding with 1 ms sampling is sufficient

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Maximum dynamics

Dynamics

– Dynamics = acceleration performance

– Maximum dynamics = mechanical time constant

Influencing factors

– Motor design

– Mechanics at motor output

– Power supply & available peak currents

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High dynamic motors

Low mass inertia

Low torque needed for motor acceleration

High overload capability

High peak torques for fast acceleration

High efficiency

Energy goes into motion!

From 0 to nominal speed in milliseconds! 100%

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Position accuracy

Theory: Position accuracy

– Position accuracy = sensor resolution

In practical: Influencing factors

– Backlash, mechanical play (e.g. gears)

– Elasticity (e.g. couplings, belts), slip

– Sensor accuracy

– Not optimally tuned controlled parameters

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Traps: Power train

Acceleration / deceleration:

– High motor currents!

– Energy recovery (-> back feeding)!

Motor

– Cyclic motion: RMS current <= max. continuous motor current?

Power stage of motion controller

– Continuous / max. current (duration) sufficient?

Power supply

– Peak currents, capability to handle energy recovery,

buffering capacities, ...?

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Conclusion: The Solution …

… is more than

drive engineering

and single components.

… has to be focused on

the comprehensive

requirements.

(Even soft factors!)

© 2017 maxon motor ag WJ, 2017-04

Join the spirit

of success!

maxon motor: selection of controllers and integrated...

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