Navigation System for Modular Agricultural Machines using Optimal Control Methods and Industrial Standard Network

Juha Backman

Navigation System for Modular Agricultural Machines using Optimal Control Methods and Industrial Standard Network

Julkaisun otsikon käännös: Navigointijärjestelmä modulaarisille maataloustyökoneille käyttäen optimisäädön menetelmiä ja teollisuuden standardiväyliä

Juha Backman

Tutkimustuotos: Doctoral Thesis › Collection of Articles

Abstrakti

Maataloudessa on edelleen kasvava tarve tehostaa työkoneiden käyttöä. Kehitys on johtanut yhä suurempiin työkoneisiin ja enenevässä määrin automaation käyttöön. Haasteena on, että sekä traktorien että työkoneiden valmistajia on suuri määrä. Koneiden yhteensopivuutta ratkaisemaan on kehitetty ja yleisesti hyväksytty ISO 11783 standardi, joka määrittelee tiedonsiirron traktorin ja työkoneen välillä. Työn motivaationa oli vähentää kuljettajan työmäärää sekä tehostaa ja tarkentaa peltotyötä. Tämä saavutettiin korvaamalla ihmisen ohjaus automaattisella navigointijärjestelmällä. Koska työkoneiden koko kasvaa, ne ovat yhä useammin hinattavia. Nykyiset kaupalliset navigointijärjestelmät eivät ota hinattavia työkoneita huomioon. Vaatimusten saavuttamiseksi asetettiin kaksi tavoitetta: 1) tutkia ja kehittää navigointijärjestelmää, joka kykenee alle 10 cm työkoneen sivuttaisvirheeseen vähintään 12 km/h työnopeudella todellisissa pelto-olosuhteissa. 2) Pohtia ja esittää menetelmiä, joilla hajautettu ja yleinen yhdistetty navigointijärjestelmä voidaan toteuttaa käyttäen standardin ISO 11783 määrittelemää tiedonsiirtoa. Ratkaisu oli käyttää epälineaarista malliprediktiivistä säädintä (NMPC) polun seurantaan. NMPC:tä käyttäen on mahdollista tehdä säädin, joka ohjaa sekä traktoria että työkonetta optimaalisella tavalla. NMPC:ssä referenssi on kuitenkin aikaperusteinen trajektori ja polunseurannassa referenssi ei ole sidottu aikaan. Muutoksia säätimeen oli tehtävä. Myös muita ongelmia, jotka aiheutuivat NMPC:n käytöstä, ratkaistiin: NMPC tarvitsee systeemistä tarkan tilaestimaatin, joten luotiin optimitilaestimaattori yhdistämään paikalliset ja globaalit paikanmittaukset. Järjestelmässä on suuri määrä asetettavia parametreja, joten puoliautomaattinen viritysjärjestelmä kehitettiin. Referenssipolun tulisi olla toteutettavissa oleva, joten rajoitukset huomioiva polunsuunnittelualgoritmi kehitettiin. Myös NMPC:hen yhdistetty esteiden väistö kehitettiin. Peltotestit osoittivat että kaikki tavoitteet saavutettiin. Navigointijärjestelmän tarkkuus oli sallituissa rajoissa ja järjestelmä kykeni toteuttamaan kokonaisen peltotyön ilman ihmisen puuttumista ohjaukseen, mukaan lukien sähkötolppien väistön. Esimerkkitapauksiin perustuen tarvittavan siirrettävän informaation määrä yhdistetyssä navigoinnissa havainnollistettiin. Johtopäätöksenä voidaan todeta, että on mahdollista toteuttaa yhdistetty navigointijärjestelmä perustuen ISO 11783 standardiin ja hajauttaa mittaukset ja toimilaitteet väylälle.

Julkaisun otsikon käännös	Navigointijärjestelmä modulaarisille maataloustyökoneille käyttäen optimisäädön menetelmiä ja teollisuuden standardiväyliä
Alkuperäiskieli	Englanti
Pätevyys	Tohtorintutkinto
Myöntävä instituutio	Aalto-yliopisto
Valvoja/neuvonantaja	Visala, Arto, Vastuuprofessori Oksanen, Timo, Ohjaaja
Kustantaja	Aalto University
Painoksen ISBN	978-952-60-5392-9
Sähköinen ISBN	978-952-60-5391-2
Tila	Julkaistu - 2013
OKM-julkaisutyyppi	G5 Tohtorinväitöskirja (artikkeli)

Tutkimusalat

työkoneen navigointi
polun seuranta
epälineaarinen malliprediktiivinen säädin
esteen väistö
ohjelmistoarkkitehtuuri
simulointi
virittäminen
tilan estimointi

Pääsy asiakirjaan

http://urn.fi/URN:ISBN:978-952-60-5391-2

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title = "Navigation System for Modular Agricultural Machines using Optimal Control Methods and Industrial Standard Network",

abstract = "In agriculture, there is a growing demand to increase the efficiency of machinery. This has led to increasingly larger machines and an increasing usage of automation. The challenge is that there are numerous different combinations of tractors and implements and they all have to work together. The ISO 11783 standard is a widely accepted standard for realising an information exchange between the tractors and implements. The motivation for this thesis was to reduce the workload of the driver and also to improve the efficiency and accuracy of field work. This was achieved by removing the human being from behind steering wheel and letting the navigation system do the driving. Because of their size, implements are more commonly towed these days. The navigation system should also take into account the towed implement. In most commercial products, only the tractor is considered. Two specific goals were set: 1) to study a combined navigation system that is able to drive at a speed of at least 12 km/h with less than 10 cm lateral error under real field conditions; 2) to discuss and present the ways in which a decentralised and generic combined navigation system can be realised using the ISO 11783 network. The solution was to use Nonlinear Model Predictive Control (NMPC) in path tracking. With NMPC, a controller can be realised that controls the motion of both the tractor and the trailer in an optimal manner. In NMPC, the reference trajectory is usually coupled with time. However, in path tracking for agricultural navigation, it is more suitable not to couple the positions of the tractor and the implement with time. Hence, the NMPC had to be modified. Also, other difficulties that arise from the usage of NMPC had to be overcome: the NMPC needs an accurate estimate of the state, so an optimal state estimator that merges the local and global position measurement was developed. Semi-automatic tuning methods were developed for tuning and configuring the numerous parameters needed for combined navigation. The reference path should be feasible, so a feasible path planning algorithm was developed. Additionally, a collision avoidance method was developed and incorporated within the NMPC. The results of the field tests show that the goals were met. The accuracy of the navigation system is within the given limits. The system is also able to complete the field work without human intervention, including making headland turnings and avoiding electricity poles. The required information on combined navigation has been illustrated based on the case studies. It is possible to build system based on the ISO 11783 standard and distribute sensors and actuators.",

keywords = "implement guidance, path tracking, nonlinear model predictive control, collision avoidance, software architecture, simulation, tuning, state estimation, ty{\"o}koneen navigointi, polun seuranta, ep{\"a}lineaarinen malliprediktiivinen s{\"a}{\"a}din, esteen v{\"a}ist{\"o}, ohjelmistoarkkitehtuuri, simulointi, viritt{\"a}minen, tilan estimointi, implement guidance, path tracking, nonlinear model predictive control, collision avoidance, software architecture, simulation, tuning, state estimation",

author = "Juha Backman",

year = "2013",

language = "English",

isbn = "978-952-60-5392-9",

series = "Aalto University publication series DOCTORAL DISSERTATIONS",

publisher = "Aalto University",

number = "169",

address = "Finland",

school = "Aalto University",

}

TY - THES

T1 - Navigation System for Modular Agricultural Machines using Optimal Control Methods and Industrial Standard Network

AU - Backman, Juha

PY - 2013

Y1 - 2013

N2 - In agriculture, there is a growing demand to increase the efficiency of machinery. This has led to increasingly larger machines and an increasing usage of automation. The challenge is that there are numerous different combinations of tractors and implements and they all have to work together. The ISO 11783 standard is a widely accepted standard for realising an information exchange between the tractors and implements. The motivation for this thesis was to reduce the workload of the driver and also to improve the efficiency and accuracy of field work. This was achieved by removing the human being from behind steering wheel and letting the navigation system do the driving. Because of their size, implements are more commonly towed these days. The navigation system should also take into account the towed implement. In most commercial products, only the tractor is considered. Two specific goals were set: 1) to study a combined navigation system that is able to drive at a speed of at least 12 km/h with less than 10 cm lateral error under real field conditions; 2) to discuss and present the ways in which a decentralised and generic combined navigation system can be realised using the ISO 11783 network. The solution was to use Nonlinear Model Predictive Control (NMPC) in path tracking. With NMPC, a controller can be realised that controls the motion of both the tractor and the trailer in an optimal manner. In NMPC, the reference trajectory is usually coupled with time. However, in path tracking for agricultural navigation, it is more suitable not to couple the positions of the tractor and the implement with time. Hence, the NMPC had to be modified. Also, other difficulties that arise from the usage of NMPC had to be overcome: the NMPC needs an accurate estimate of the state, so an optimal state estimator that merges the local and global position measurement was developed. Semi-automatic tuning methods were developed for tuning and configuring the numerous parameters needed for combined navigation. The reference path should be feasible, so a feasible path planning algorithm was developed. Additionally, a collision avoidance method was developed and incorporated within the NMPC. The results of the field tests show that the goals were met. The accuracy of the navigation system is within the given limits. The system is also able to complete the field work without human intervention, including making headland turnings and avoiding electricity poles. The required information on combined navigation has been illustrated based on the case studies. It is possible to build system based on the ISO 11783 standard and distribute sensors and actuators.

AB - In agriculture, there is a growing demand to increase the efficiency of machinery. This has led to increasingly larger machines and an increasing usage of automation. The challenge is that there are numerous different combinations of tractors and implements and they all have to work together. The ISO 11783 standard is a widely accepted standard for realising an information exchange between the tractors and implements. The motivation for this thesis was to reduce the workload of the driver and also to improve the efficiency and accuracy of field work. This was achieved by removing the human being from behind steering wheel and letting the navigation system do the driving. Because of their size, implements are more commonly towed these days. The navigation system should also take into account the towed implement. In most commercial products, only the tractor is considered. Two specific goals were set: 1) to study a combined navigation system that is able to drive at a speed of at least 12 km/h with less than 10 cm lateral error under real field conditions; 2) to discuss and present the ways in which a decentralised and generic combined navigation system can be realised using the ISO 11783 network. The solution was to use Nonlinear Model Predictive Control (NMPC) in path tracking. With NMPC, a controller can be realised that controls the motion of both the tractor and the trailer in an optimal manner. In NMPC, the reference trajectory is usually coupled with time. However, in path tracking for agricultural navigation, it is more suitable not to couple the positions of the tractor and the implement with time. Hence, the NMPC had to be modified. Also, other difficulties that arise from the usage of NMPC had to be overcome: the NMPC needs an accurate estimate of the state, so an optimal state estimator that merges the local and global position measurement was developed. Semi-automatic tuning methods were developed for tuning and configuring the numerous parameters needed for combined navigation. The reference path should be feasible, so a feasible path planning algorithm was developed. Additionally, a collision avoidance method was developed and incorporated within the NMPC. The results of the field tests show that the goals were met. The accuracy of the navigation system is within the given limits. The system is also able to complete the field work without human intervention, including making headland turnings and avoiding electricity poles. The required information on combined navigation has been illustrated based on the case studies. It is possible to build system based on the ISO 11783 standard and distribute sensors and actuators.

KW - implement guidance

KW - path tracking

KW - nonlinear model predictive control

KW - collision avoidance

KW - software architecture

KW - simulation

KW - tuning

KW - state estimation

KW - työkoneen navigointi

KW - polun seuranta

KW - epälineaarinen malliprediktiivinen säädin

KW - esteen väistö

KW - ohjelmistoarkkitehtuuri

KW - simulointi

KW - virittäminen

KW - tilan estimointi

KW - implement guidance

KW - path tracking

KW - nonlinear model predictive control

KW - collision avoidance

KW - software architecture

KW - simulation

KW - tuning

KW - state estimation

M3 - Doctoral Thesis

SN - 978-952-60-5392-9

T3 - Aalto University publication series DOCTORAL DISSERTATIONS

PB - Aalto University

ER -

Navigation System for Modular Agricultural Machines using Optimal Control Methods and Industrial Standard Network

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