Collision Preventionand Area Monitoring

with the LMSLaser Measurement System

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A v o i d . . .. . . collisions

SICK Laser MeasurementSystems are employed whereverlong-range collision prevention isrequired.The gap-free monitoring zonescan be individually adapted tomeet even especially difficulttasks.The system does not just reportinfringements of the optical fieldsby objects or obstructions, butalso provides the precise positionof the particular infringement.

Special advantages ofthe system

• freely adjustable monitoredfields

• monitored fields easilychanged (e.g. when structuralalterations are made)

• active, dynamic measurementprinciple: thus fullyindependent of objectillumination

• unaffected by ambient light• no mutual interference when

several scanners are usedsimultaneously

• operating temperatures from–30°C to +50°C

• very long range(up to 80m, up to 180°scanning angle)

•

• dynamic field changespossible during mobileoperation (AGV)

• navigational support byreporting of reflectormarks

• rain and snowsuppression in outdoorapplications

• active fog correctionprevents erroneousswitching

• simple system structurethanks to use of standardcomponents

Typical areas of use

• collision prevention forcontainer cranes in lanes

• collision prevention aroundswinging facilities e.g. cranearms

• checking jut-out/overhangon conveyor belts and inhigh-bay warehouses

• non-contact collisionprevention on AGVsoutdoors

• monitoring closing actionsof gates and barriers

Fig. 1: LMS laser scanner, LMI interface.

E x a m p l e s

Collision prevention oncontainer cranes

Lanes

Several container cranes areusually operated on the sametracks. This lane is used forlateral movements of thecrane and the crane drivercan only see it with difficultyand sometimes not at all.Costly collisions cannot beruled out if obstructions suchas vehicles, containers orother objects are in the way.

In this application the LaserMeasurement System takeson the function of a forward-looking, optical bumper.Precisely defined monitoredfields provide reliableswitching signals fordeceleration and for stoppingthe crane.

Crane – CraneCrane – Ship

Crane booms often need towork close in to shipstructures as a result of thehigh container loading densityon board. The low operatingdistance creates a highpotential for possiblecollisions that would causeconsiderable damage.The Laser MeasurementSystem is responsible fornon-contact distancemeasurements in thesesituations. The systemcontinuously measures thespace available within a freelyselectable, 2–dimensionalmonitoring field and usesswitching signals to the cranecontrol system to indicatewhen distances aredangerously low.

Advantages

• precisely definablemonitoring zones

• long ranges• resistant to maritime

climates• enclosure rating: IP 67• for ambient temperatures of

-30°...+50°C• simple retrofitting• no mutual interference

Advantages

• freely selectable fieldgeometries

• short reaction times• any mounting position• automatic pollution

indication

Fig. 3: Preventing collisions between crane andship.

Fig. 2: Monitoring a container crane lane

AGVs – AutomaticGuided Vehicles

Collision preventionVehicle density and AGVspeeds are constantlyincreasing in order to meetturnaround times that aregetting shorter and shorter.Simple collision prevention,e.g. between bumper andelectro-mechanical switchingstrips, is no longer sufficient.The LMS Laser MeasurementSystem offers excellentperformance features thatkeep pace with AGVdevelopments.Freely selectable monitoringfields scan lanes as opticalradar, without any contact.Obstructive objects lead to adecelleration of the AGV ortrigger a stop signal.

NavigationAGVs are kept 'on course' bya variety of navigationalequipment. Systems such asthose guided by wire,however, do not allow anyflexible changes to be madeto the pre-defined lanes.Systems with 'free navigation'are increasingly coming to thefore. The LMS LaserMeasurement System reliablysupports the on-boardcomputer. In addition to purecollision-prevention tasks theLMS provides signals when areflector (reflector mark) isdetected. The LMS providesthe relative angle anddistance to the reflector markdetected.The on-board computer canuse this information update tocompensate for deviationscaused, for example, byslippage.

Advantages

• long range• any shape for monitored

fields• freely definable fields for

negotiating curves• dynamic fields with

automatic expansion in linewith speed

• rain and snow suppression• simple system structure

thanks to use of standardcomponents

• easily integrated• automatic pollution indication

Advantages

• high measurement accuracyat long range – even in rainand snow

• easily integrated• just one system for both

collision prevention andnavigation

• data output in real time• automatic pollution indication

Fig. 4: Collision prevention on an AGV (container).

Fig. 5: Collision prevention on an AGV (air freight).

Warehous and conveyortechnology

Warehouse technology

Modern goods handling islargely automated. Servicemodules such as, for example,storage and retrieval units forhigh-bay warehouses (RGBmodules) approach theappropriate storage area inautomatic mode.The LMS Laser MeasurementSystem helps prevent costlydamage caused by collisionswith overhanging parts.Mounted on the RGB, the LMSmonitors the lanes between thebays for any overhang while inmotion. The monitoring fieldsare selected in such a way asto form an optical curtainparallel to and in front of thebays. Should any overhang bepresent the RGB is stoppedreliably and in good time.

Conveyor systems

Overhang and excess heightsoccur relatively frequently inconveyed goods, e.g. palletloads. Parts jutting out over thepallet can cause considerabledamage or can themselves bedamaged during transport.Checking overhang usingsimple photoelectric switches,etc. is generally unsatisfactoryin practice. The LMS LaserMeasurement System, on theother hand, forms a complete,gap-free, optical gate andoverhang or excess heights areimmediately registered. Theareas monitored can be flexiblyadapted to local circumstancesand have extremely rapidresponse times.A supplementary heightclassification of the transportedgoods can be carried out ifseveral fields of varying sizesare set up directly above theconveyor section. A separateswitching signal is available foreach height class.

Advantages

• long range• short response time• easy integration• complete cover on the sides

of the RGB• monitored fields can be

changed rapidly in the eventof structural alterations

• high detection reliability• automatic pollution indication

Advantages

• complete area monitoring• easy integration and

retrofitting• rapid reaction times• height classification

possible• optional volume

determination of thetransported goods isavailable

• high detection reliability

Fig. 6: Checking overhang in a high-bay warehouse.

Fig. 7: Checking overhang on conveyor equipment

Industrial sensors

Automated processes makeincreasing demands on thesensor systems employed.Basic functions more and moreoften require the addition ofsupplementary features. TheLMS Laser MeasurementSystem meets the need forboth in exemplary fashion.

Gate and barrier control

The LMS system's flexiblemonitoring fields can coverlarge areas. Entrances andexits with mixed pedestrian andvehicular traffic, e.g. worksentrances, requiresupplementary differentiationbetween persons and vehicles– in addition to purely basicfunctions (namely, automaticgate opening). This then hasthe advantage that the gate isonly opened when a vehicletriggers the request. Personneldo not cause the gate to openso that no attempt is made towalk on the traffic lane.

Sliding gates

Automatic sliding gates areoften used in large halls. In, forexample, aircraft hangars thegates are only opened forbringing in an aircraft or takingone out and then closeautomatically afterwards. Herethe LMS system is responsiblefor automatically providing afree signal for the closing areato prevent extremely costlycollisions between the gate andaircraft parts. The long range ofthe LMS, and in particular itscomplete, gap-free cover of thegate area, enable it to handlethe task without any problem.

Advantages

• flexible monitored areas forindividual adaptation to localcircumstances

• distinguishes betweenpersons and vehicles usingits 'object size' standardfunction

• rain and snow suppression

Advantages

• long range and reliabledetection

• no limitations caused byreflective surfaces

• monitored area can besegmented allowing the useof differentiated switchingsignals

Fig. 8: Providing an 'area free' report at barriers.

Fig. 9: Providing an 'area free' report at sliding gates.

•Large monitoring area withradius up to 80 m and field ofview of up to 180°

• Active system – no externalillumination necessary

• Gap-free monitoring• Individually adaptable

monitored areas• Rain / snow suppression

through integrated evaluation• Fog correction prevents

erroneous switching• Self-testing• Simple mounting with a variety

of mounting sets• Ambient temperatures of

-30°C...+50°C• Extremely robust housing with

IP 65 / IP 67

221

211

Fig.15: The 291 laser scanner.

The laser scanner as an intelligent protective shield

LMS 211 laser scannerwith dust prevention shield,100° scanning angle; IP 67; withinternal and front windowheating,3 x PNP switching outputs,RS 232 / 422 data interface.

LMS 221 laser scanner180° scanning angle; IP 67; withinternal heating,3 x PNP switching outputs,RS 232 / 422 data interface.

LMS 291 laser scanner180° scanning angle; IP 65;3 x PNP switching outputs,RS 232 / 422 data interface.

Fig. 14: The 221 laser scanner.

Fig.13: The 211 laser scanner.

Material ReflectivityCardboard, matt black 10%Wood (raw pine, dirty) 40%PVC, grey 50%Aluminium, black anodised 110...150%Plaster, white 100%Reflectors > 2000%

LMS 211 / 221 / 291 technical dataRange, max. 80 mRange for 10% reflectivity 30 mResolution 1 cmSystematical error typ. 4 cm, max 6 cmScanning angle LMS 211

LMS 221 / 291100°180°

Angular resolution 1°/0.5°/0.25°Response times 13 ms/ 26 ms/ 53 msPower supply 24 V DCOutputs: switching outputs

interface3 x PNP; 24VRS 232 / 422; selectable

Enclosure rating LMS 211 / 221LMS 291

IP 67IP 65

Ambient temp. LMS 211 / 221 LMS 291

- 30°...+ 50°C0°... + 50°C

Dimensions LMS 211 / 221(W x H x D) LMS 291

ca. 352 x 265 x 202 mm³ca. 155 x 185 x 156 mm³

Fig.. 16: Range in relation to the object's reflectivity.

The laser scanner's range isbasically dependent on theobject's surface. The greater thereflectivity of the object, thelonger the measurementsystem's range. The over-dimensional range reserve,however, ensures that the LMSreliably detects even weaklyreflective objects. See the tablebelow for the reflectivity of sometypical materials ('KodakStandards'):

Rain and snow have noeffect on the range of themeasurement system.

Please note the specialrange details and minimumreflectivity values in foggyconditions.

Far-reaching

Weatherproof