GB2432922A

GB2432922A - Systems and methods for autonomous control of a vehicle

Info

Publication number: GB2432922A
Application number: GB0701810A
Authority: GB
Inventors: James Allard; David S Barrett; Misha Filippov; Robert Todd Pack; Selma Svendsen
Original assignee: iRobot Corp
Current assignee: iRobot Corp
Priority date: 2004-10-22
Filing date: 2005-10-20
Publication date: 2007-06-06
Anticipated expiration: 2025-10-20
Also published as: GB2432922B; GB0701810D0

Abstract

Systems and methods for autonomous control of a vehicle include interruptible, behaviour-based, and selective control. Autonomous control 100 is achieved by using actuators that interact with input devices in the vehicle. The actuators (e.g., linkages) manipulate the input devices (e.g., articulation controls and drive controls, such as a throttle, brake, tie rods, steering gear throttle lever, or accelerator) to direct the operation of the vehicle. Although operating autonomously, manual operation of the vehicle is possible following the detection of events 116 that suggest manual control is desired. Subsequent autonomous control may be permitted, permitted after a prescribed delay 126, or prevented 128. Systems and methods for processing safety signals and/or tracking terrain features are also utilized by an autonomous vehicle.

Description

SYSTEMS AND METHODS FOP. CONTROL OF A VEHICLE

Field of the Invention

[00011 The present invention relates generally to control of unmanned ground vehicles and.

more specifically, to variations in the control of unmanned ground vehicles in response to enviromnental changes or operator intervention.

gckground of the Invention [0002J Vehicles and equipment that operate with little or no operator intervention are desirable partly because they remove the operator from harm's way in dangerous applications and because they offer direct labor cost savings in commercial applications. In many instances, this limited intervention is exemplified by an operator removed from the confmes of the vehicle its lf and placed in a location with a remote control device that interfaces with and controls the vehicle. In this configuration, however, the operator typically must directly and continuously monitor the vehicle and its surrounding environment, adjusting, for example, vehicle speed and direction, as needed. In particular, when a task is complex, the operator must carefully monitor the vehicle or equipment to the point where any simplification of the operator's tasks is negated by the high level of concentration required to ensure the vehicle avoids obstacles, hazards, and other terrain features in its path, thereby preventing accidents. This requires considerable effort by the operator, a significant investment in skilled operator training, and places severe limitations on mission duration and objectives.

[0003J In a typical environment, a vehicle can encounter any number of unforeseen hazards. A vehicle can also create or exacerbate a hazard. In either case, there is the potential that the vehicle may endanger persons or property. Accordingly, an operator generally pays particular attention to events that may result in dangerous conditions. This additional safety concern negatively affects mission effectiveness because it directs the operator's attention away from the particulars of the task the vehicle is performing. Additionally, an operator may become over helmed by the degree of oversight and attention required and may faf I to recojze one or ncre obstacles or hazards in th path of the;ehfck, potentiall resL1tin2 i an accident.

[0304J From the foregoing. it is a;parerit that there is a direct riee for efflcie:, oni.'is cntrci 0i e:ice or equipment that -elie-es the operator of a:cst. inot alL oo;;e;jcj1ai ovrsigh1. The vehicle or euipniei-!t needs to accmpiish its assigned tasks whi'e cDm:e:13atin for the eirc:im in an autncniouE. fashio hut still be responsive to the attempts by an operatoi-10 rsu:ne control. The *chicle must also e;isure the safety of the its surroLndinas.

Summary of the Invention

100051 In one aspect, the invention relates to a method for control of a vehicle, the method including the steps of: identifying at least one input device in the vehicle, providing at least one actuator associated with the at least one input device, and controlling the vehicle based at least in part on at least one of an interruptible autonomous scheme, a behavior based autonomous scheme, a selective scheme, and a safety scheme.

[0006J In another aspect, the invention relates a system for control of a vehicle, the system including: means for controlling the vehicle, means for actuating the vehicle control means, and means for controlling the vehicle based at least in part on at least one of an interruptible autonomous controller, a behavior based autonomous controller, a selective controller, and a safety controller.

[0007J In one aspect, the present invention provides systems and methods for interruptible autonomous control of a vehicle. Although operating autonomously, an operator can override the autonomous control to the extent necessary to, for example, adjust the progress of the vehicle. Mission effectiveness is increased because the operator is relieed frcrn ncst, fno all.

navigational oversight of the vehicic-. Further. safcty systems, typicaill' running amonomcus-are Drc,ded This n'pro es cle safet r& ab I't., and aeceases or ci' i't tr -r manual irterventjcn.

[00O' Th irventio:i feati:es mneucd for iupt.!e oncrnous ccntrc c-f a vf:'.

a dis!ssccj:tjc:: !etee: a.e-ice's in deces t assc.:iat=c act: io:s -e de:er'.

!no:1 ce r'::' an:c-e::-r fr.-: ci sic. a c:---: :.g. -: other device that directs vehicle pc-sitin or motion and that rny not be directly nc:!ed E-umaii operao'-. in some ernbcdinents. the input de;ice is an articulation control thaL isaI1; directs apparatus connected to the vehicle. In an autonomous vehicle, the actuator directly mampulates the linkage or is attached to the i;iput device.

[0009J In certain embodiments, auto:iomous control is inten-upted when a disassociation between the input device and its actuator is detected. For example, if the input device is a brake and an cpc;-aoT depresses the brake, the latter will separate from its actuator. The separation (i.e., disassociation) is detected and the autonomous control of the brake is discontinued. In other embodiments, autonomous control is reestablished after the operator ceases manipulating the input device (e.g., removes his or her foot from the brake, thereby reassociating the control surface and the actuator). Different embodiments prevent the reestablisimient of autonomous control. In either case, proximity sensors and strain gauges typically detect the disassociation and reassocjatjon.

100101 The invention also features a method where the detection of a disassociation initiates a shutdown sequence. In some embodiments, this is used to enhance operational safety.

100111 Another aspect of the invention includes a system for interruptible control of a vehicle.

This system includes a controller, such as a microprocessor or microcontroller, in communication with the detectors and actuators, that manages the discontinuation and reestablishment of autonomous control. The controller acts in accordance with control policies that characterize the behavior of the input device in different vehicle operational modes (e.g., autonomous. manual). A further aspect of the invention includes a system that initiates and controls a shutdown sequence after detection of a di sassociatior between a controi surfce and an actuator.

Eh3i2 in another aspc.. the prcseni inention preis 2 s.s:eni and nethcd for bitn;-csed control of an auio:;ornous vei'icle. While 3oeratin-autoncmo:s. the i:fck is avne cf'is s.LToundngs. pa:-ticu:r!v the locaii:n ard ci:acte: of'n fe:tres tim: :::a e cie.

2e:.e t'iese:-:.iri iea.:':-s r::ee::t ha::c. t i-i: :;- [01131 The i;-vertion features a method for the bei-avioi-b'sed c'rr:trol ca:: :tancm:s vic :1ere several behavo-s are aas:ciated with the actuators that aanipate input devices tl:st drect the vehicle. .n iniut device may be an operator input device that directs at!ast part of the vehicle (e.g.. one or more oa steeting cheel, handle, brake pedal. accelerator, or throttle).

The input device also may be device directly or indirectly coniectin the operacor input device to a controlled element (i.e., the object in the autonomous vehicle ultimately controlled by the operator input device. For example, the operator input device may be a throttle. and the input device may be the thrctik iody. Although a human operator typically accesses and manipulates the operator input device, the input device need not be accessible or operable by the human operator.

100141 A behavior is a program that proposes an action based on sensor data, operator input, or mission goals. Actions are typically grouped into action sets, and the action sets are generally prioritized. The actions within an action set are termed "alternative actions," and each alternative action generally has a corresponding preference. The preferences allow for the ranking of the alternative actions.

100151 Multiple behaviors continuously propose actions to an arbiter. The arbiter continuously decides which behavior is expressed based on a weighted set of goals. The arbiter selects the action set with the highest priority, and also selects the alternative action from within the selected action set with the highest corresponding preference. A behavior based system can include many behaviors and multiple arbiters, and multiple arbiters can be associated with an actuator.

Multiple arbiters associated with an actuator are sometimes referred to as "stacked arbiters." An actuator is typically a ser%o_systcrn and transmission in physicsi contact with the ex!sting input devices in the vehicle.

In sonic e: xija-e:;ts. th behavio!-chrr:r1erize Vie operatfci:1:mdi cftl:c vdije.

T1-r --.. -.. - --* *----.--- ---------------r _.. . _ ----_. -- _.

c*:era:fc:, rd tG1J:i-3us 12meT cration. in the manned operation ncie a vehicle Lie c:ckji: drives the vehic!e Ls -j:siradtcrai:cnur2:-in::: --L1, -r ---.-----.

----;__.________,__ ---._; vehicle from a safe stcnd off distance through a portable operator control unit that 2'l!cvs th cperator to clfrectly ccaman the vehicle. In the assisted reivote tele-operation mode, the dismounted operator can engage assistie behaviors' that facilitate missior execution. These assistive behaviors use the vehicles senscrs. control system, and perception and localization subsystems to add sho'-t-trrn. saYe, self-navigation finctionality to the vehicle. Examples of assisted behaviors include active obstacle avoidance, circling in place and deploying payloads based on sensor inpuL. Such an assist allows the operator to focus more on the mission and less on the continuous demand of driving. In the autonomous mode, the vehicle uses an arbitrated behavior based technique to perfomi a tactically significant mission. Examples of such missions include following a moving object at a fixed distance and travelling through a pre-recorded set of fixed GPS waypoints while actively performing obstacle avoidance. Each mode can include a set of alternative behaviors that the vehicle can take to accomplish its task. In some embodiments, the alternative behaviors are ranked by priority or preference and an arbiter selects the behavior to be performed. The behavior can then operate the corresponding vehicle control accordingly.

[0017J In some embodiments, the behaviors include trajectory sets and, in further embodiments, the behavior includes adjusting the translational velocity, or rotational velocity, or both, of the autonomous vehicle, typically in response to data received from sensors or a map of terrain features located around the vehicle.

[OO18J Another aspect of the invention includes a system for behavior based operation of an autonomous vehicle that includes a controller, such as a microprocessor or microcontroller, that provides the host environment for the multiple resident behavior programs and the aroiter program and, in response to the behaviors, operates one or more ehicie controls using actuators.

The controller also communicates with one or more localization or perception sensors, and usfa or-o'-:;:*-oca!f::.f:: ze-cy-hYe"s hii!ds a Vc!iCje cent-ic t:rrain featuc !UPS the s>t and spifE the aotio:;s to be perf.;:-med.

1::.)J I: -anothe: iL:o:. oi'esen L nra. a s,s:e:i and method for miii'-Far hfcie. ;-: ig on. fb: :cc!. ::: to compensate for variations in the task and changes in the environment around th vehicLe. Thi3 increases mission effectiveness and promotes the safe operation of the vehicle.

10020J The inventior features rjj for selective control of a ehicle in response to receiving a mode select command. In some embodiments, the mode select command includes one or more of a manned operation, remote unmanned tele-operation, assisted remote unmanned tele-operations, and autonomous unmanned operation. After receipt of the mode select command, a specific representative set of vehicle control behaviors are enabled that allow operation in that specific mode.

[00211 Another aspect of the invention includes a system for selective control of a vehicle that includes a receiver for receiving the mode select command. A controller, such as a microprocessor or microcontroller, communicates with the receiver and executes a vehicle control program. This controller, such as a microprocessor or microcontroller, provides'the host environment for the multiple resident behavior programs and the arbiter program, and, in response to the behaviors, operates one or more vehicle controls using actuators.

[0022J In still another aspect, the present invention provides a system and method for processing a safety signal in an autonomous vehicle. While operating unmanned, the vehicle uses its on-board local area sensors and its perceptual context software to detect the presence of unsafe conditions. The vehicle also receives and acts on emergency signals sent by the operator. In either case, processing of the detected or signaled information leads, in some embodiments, to the manipulation of vehicle input devices in a maimer to ensure the proper response to the detected or signaled information.

f0023J Given the importance of safe vehicle operation, some embodiments of the invention include redundant communication paths for conveying the detected or signaled information.

These eommuncatjo paths may include; a hard-wired electrical safet. circuit, a firmv are b2sed dedjcaid m!cronroccssor actuator contr network, and a collection of software based fault detectfn code residing in the main vehicle control computer. Operating in parallel. these ::::itip!e C m: :ncatjon pat-s r.' ide a rciust method to ensure Lht det.cted cr sied safe:- 100241 iother aspect of the inve; Lion inciudes a systen-for processing s safcty signaL This system includes a control!e. such as a ricroprocessor or microcontroller. in c:n'-crtjG with actuators via a transmitter uSIng multiple communication lifts. in respcrse to detected or signaled information, the controller, in certain embodiments, instructs the actuators to manipulate one or more vehicle input cievicec. typically using Ini:ages, tc affect a safe response to a potentially (or ctua!ly) unsafe condition. !n various embodiments, the controller acts in accordance with control policies that characterize the behavior of the input device in different vehicle operational modes (e.g., autonomous, manual).

[0025J Although operating autonomously, an operator can override the autonomous control to the extent necessary to, for example, adjust the progress of the vehicle. Tactically significant mission effectiveness is increased because the operator is relieved from most, if not all, safety oversight of the vehicle. Further, safety systems, typically running autonomously, are pyovided.

This improves vehicle safety, reliability, and decreases or eliminates the need for manual intervention.

[0026J In still another aspect, the present invention provides a system and method for tracking one or more terrain features by an autonomous vehicle. While operating autonomously, the vehicle uses its on-board local area sensors and its perceptual context software to determine the location and character of terrain features, which may be obstacles or targets. Because these terrain features can represent hazards or targets to the vehicle, the vehicle preferably compensates by altering its trajectory or movement.

(0027 The inventior features a method for tracking terrain features using localization and percertion sensors. Localization se:sors detern-iine the location and orie:itation of the autonomo.is vehicle.ln some embcd nents, the lccdizatjon sensors include sensors to measure pitch, rol!, and yav. Other eilbudirriel:ts include a11 inerttai 2v a'cn S'sten ccpc a gioba rcsiti:ain: szeni. or an:!c.:nete:-. Pceptin sensors assess the er o:er scme cie::ts, th p:ccDtion suso:s inc!ude a LiDP. (h DeccL.o sr o: laser. stni. stereo ision sye. infri-ed :adr: cra:-OO28 Usii these sensors. embodiments of the i:'ention compute the location cfd ree-'nt ieTain features detected and stor. the location infon1aLion ir memor'. Whe Ge oithuts of iFie sensors change, the Ioctions are updated accordingly. To conserve memory. cope viith fault: sensor data, and accommodate mo'ing objects, some embodiments discard oider Iocatiou data deemed "stale' due to the passage of time or distance traveled. In response to the determining up-to-date locations of terrain features, the autonomous vehicle adjusts its trajectory. In certain embodiments, adjusting the trajectory includes selecting a preferred trajectory from a group of several ranked alternative trajectories.

100291 Another aspect of the invention includes a system for tracking terrain features that includes one or more controllers, such as microprocessors or microcontrollers that communicates with the localization and perception sensors. The controllers also communi cate with a vehicle-based memory for storing location information. In some embodiments, the system inclqdes adjustment logic that operates to adjust the trajectory of the autonomous vehicle in response to the presence of terrain features.

100301 Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in conjunction with the accompanying drawings, illustrating the principles of the invention by way of example only.

Brief Description of the Drawings

100311 The foregoing and other objects, features, and advantages of the present invention, as well as the invention itself, will be more fully understood fi-ori the following description of varicus embodiments, when read together with the accompanying dra-ings, in which: Figure 1 is a flo chart depicting a method for interruptible utopomous ccitrol of a ehic!e in accc once:th an blt'IieLL!t:iC f erj,ioi-: Fir,: j hioct dni:j a 5Stciil for Interrumible toncc' contro! of a vehicle in acccrdance wjth.n e iTnt of the iFcn c c':c r-t " c'-es Ffgre 4 is a b'ccl dsgra-' depiceng a:;steivi for ncsi a safety;-j -autonomous vehicle in acco:da:ice witi an enodirnent at the iv.'entio:: Figure 5 is a flowchart depicting a method for tracking a terrain feature b; au autonomo.' vehicle in accordance with an embodiment of the invention; c Figure 6 is a block diagram depicting a system for tracking a terrain feature by an aatunoir;oiis vehicle in accordance with an embodiment of the invention; Figure 7 is a flowchart depicting a method for the behavior based control of an autonomous vehicle in accordance with an embodiment of the invention; * Figure 8 is a block diagram depicting a system for the behavior based control of an autonomous vehicle in accordance with an embodiment of the invention; * Figure 9 is a flowchart depicting a method for multi-modal control of a vehicle in accordance with an embodiment of the invention; and * Figure 10 is a block diagram depicting a system for multi-modal control of avehicle in accordance with an embodiment of the invention.

Detailed Description

[00321 As shown in the drawings for the purposes of illustration, the invention may be embodied in systems and methods for controlling vehicles, where the systems and methods compensate, with little or no operator intervention, for changes in the environment around the vehicle.

Embodiments of the invention enhance overall mission effectiveness and operating safety.

[00331 In brief overview, Figure 1 is a flowchart depicting a method 100 for interruptible autonomous control of a vehicle in accordance with an embodiment of the invention. The method includes a step of first identifying one or more input devices in the vehicle (STEP 104).

An input device be an oceratcr incut device that directs at least can of the vehicle cre :.fa 3te:ri:. h-i: e t ao:e!e:atcr. cr throttle). The npuu cieice als3 rua be a ceice ircIv o idrect coinecin the operator input device to a contrcdjeci c:t i: t:::) ehic! ultin:atek ccrnro lied v the ooeratr::nu or::arnc!e. csn i-i; ccntrc! F--.::: :: :: ::.:: c:::::::. ::cu:f-equinment attached to the ehic1e. This:an incluae. for e::an-iple. a control vEed to nianfp1iL. a b1ae on a buildozer. o: a fHing apparatus cn tractor. Although a huiri2n cp;-ato: tpic2Jl accesses and manipulates the operator input device, the input device need not be accessib!e or operable by the human operator.

[00341 Next, the method 100 includes the step of providing one or more control policies (STEP 106) corresponding to the input device. Generally, the control policies determine the manner in which the vehicle operates including, for example, whether the control of the vehicle will be autonomous, manual, or a combination thereof. In addition to the identification of the input devices and control policies, the invention also includes the step of providing one or more actuators (STEP 108) associated with one or more input devices. The actuator is typically an electro-mechanjcaj device that manipulates the input device. Manipulation occurs by, for example, pushing, pulling, or turning the input device, or by any combination thereof. result of this is the autonomous control of the vehicle. Furthermore, in an embodiment of the invention, the actuators still allow manual operation of the vehicle. In other words, the presence of actuators in the vehicle does not preclude manual operation of the corresponding input devices. In some embodiments, a linkage or other mechanical transmission associates the actuator with the corresponding input device. A linkage is generally apparatus that facilitates a connection or association between the input device and the actuator. A typical linkage is a lever and pivot joint, a typical transmission is a rack and pinion device.

100351 Following the identification of the input device (STEP 104), providing the control policy (STEP 106), and providing the actuator (STEP 108), an embodiment of the invention provides autonomous control of a vehicle (STEP 102). Autonomous control allows a vehicle to be operated according to programmed instructions, with little or no operator intervention.

Autonorrious contro! tvnfca1! includes "inte!!jczeice" that allows the vehicle to comDensak ü'r ::c-s:: cot:mr a:a;: t.ai:e such as an Cst&cj. During autcno:oL:s contrc. cn:bcdjrnent oft n nior moi tors the rnut devices and ct-a dsassocac:rb-(STEp 1O. T disassc:iatio" is eneralI a:': b:ak -.---_.- *-__.,:., -.:

--

actuator by. for examp!e, depressing the.cce1eatcr. In Eome emi3 me:-1ts. tie diE::ocjatjon is detected by measuring the response of one or more sensors (STEP 112).

[00361 On detection of the disassccition (STEP 110). autonoio control is intriupte in fa of other operational mcdes (STEP 116). For example, on detection of the disassociation, a system according to an embodiment of the invention initiates a vehicle shutdown sequence (STEP 114). This can occur when, for example, the vehicle operator depresses a "panic button," thereby allowing a controlled, safe shutdown of the vehicle.

[0037] In other embodiments, following detection of the disassociation (STEP 110), autonomous control is interrupted (STEP 116) to allow manual control (STEP 118). One example of this occurs when an operator wants to increase temporarily the speed of a vehicle that is under autonomous control. By depressing the accelerator, a system according to an embodiment of the invention relinquishes the autonomous control and allows the vehicle to accelerate acco?ding to the operator's preference.

[0038] After the interruption of autonomous control (STEP 116), different embodiments of the invention detect a restored association between the input device and the corresponding actuator (STEP 120). The reassociation is typically entails the reestablishment of the physical connection between the input device and the corresponding actuator. This is generally detected by measuring the response of one or more sensors (STEP 122). In the example discussed above, the reassociatjon would occur when the operator stops depressing the accelerator, thereby allowing the accelerator to reconnect with its actuator.

[0039J Following the reassociatioii, one embodiment of the invention establishes a revised vehicle control (STEP 124). The nature of the reised vehicle control depends on the control policy proided (STEP 106). For example, in some en'bodjrnents the revised vehicle coniro! includes reEumjfl to autonomous control (STEP 102). This can occur imi-nediteJ: In other embcdjn-iems returnin to utciomous coitrol (STEP lO2 occurs after a delay (STEP 12. In iffert e:foodimers, the oprat3rn!t first i:itrvene(STp 130) before t1i sehjci.-etu-r to utc;.-contro: tSTEP i02. This conf1uratcn p:oids, br exapl, safety feure -.t:::-a::---s c::----- [O0t0! in certain embodiments, tie control c!ic7 pro'ided (STEF 106) includes eve:itina the chc1e rcrn furtr autononious control after th' inten-uitoi of autoromnous contrc ( I P 116). For exanple, in a tractor, an operator may v;ant to stop the tilling apparatus a;ici e'isure that it can not restart automatically. When a system according to an embodiment of the invention detects a disassociation becween he tiller control and the corresponding actuator (STEP 110), typically because the operator has manipulated the tiller control thereby disrupting the physical connection between the tiller control and the corresponding actuator, autonomous control is interrupted (STEP 116). Embodiments of the invention would detect the restored association between the tiller control and the corresponding actuator (STEP 120) when, for example, the operator released the tiller control, and then attempt to establish a revised vehicle control (STEP 124). Nevertheless, in this example, the control policy provided (STEP 106), includes inhibiting further autonomous control (STEP 128). Stated differently, in some embodiments, the control policy dictates, on a input device-by-input device basis, what actions are appropriate following the interruption of autonomous control. For certain input devices, such as the accelerator example discussed above, reestablishment of autonomous control is proper.

For other input devices, however, safety or other considerations dictate that autonomous control not be restored.

100411 Figure 2 is a block diagram that depicts a system 200 for interruptible autonomous control of a vehicle in accordance with an embodiment of the invention. The system 200 typically includes one or more input devices 202. An input device may be an operator input device that directs at least part of the vehicle (e.g., one or more of a steering wheel, handle, brake pedal. accelerato:-, or throttle). The input device also may be a de ice directly or indirectly connecting the operator iiput device to a ccritroled element (i.e.. th object in the autonomot!s vehicle ultimately controlled by the operator input device). For exarie. the operator input we c be a cre COnO drive cnnrol aenerlh IflcL-Ges throttle 2u6. brake 2u.

or.raisn-fssfc; s:r 211 L co::f;:tjor ircc j".t 202 is t:c:i! body (rot depic:ed), ich is Lpw11lv cc nected o the throttle 206 Oth: ::Tpe:u dc, fcs 2C' a eeri ar (nor d;e rods (nd d'fc:ec:.

i::cL: n art:.ia coz- [00421 The system 200 alsc inckdes c:: or mere control çolicies 21.4 cc:Te3pondlng to the ii-iitt device 202. Generally, the control pclicy 214 determines the maijier in which the hic!e will operate, typically allowing for vehicle control under autonomous or manual conditions, or a combination thereof The system 200 also includes one or more actuators 216 associated with the one or more input devices 202. Typically, the actuator 216 includes an electre-mechanica! dcvicc that drives the input de ice 202. In one embodiment of the invention, the actuator 216 includes one or more linkages or other mechanical transmissions 218. Generally, a linkage provides the association (e.g.,physical connection) between an actuator 216 and the associated input device 202. A typical linkage is a lever and pivot joint, a typical transmission is a rack and pinion device.

(00431 In some embodiments of the invention, the system 200 includes one or more detectors 220. The detector 220 discerns a disassociation between the input device 202 and the actuators 216. Typically the disassociation includes a break in contact or communication between the input device 202 and its associated actuator 216. By way of example, such contact or communication may be physical, or via electrical or mechanical communication, or any combination thereof In another embodiment, a disassociation can include a separation between the input device 202 and the associated actuator 216. In an alternative embodiment, the detector 220 includes a proximity sensor 222, or a strain gauge 224, or both. After a disassociation between the input device 202 and the actuator 216 has occurred, the detector 220 discerns a restored association between the same. Generally, a restored association includes a renewed contact or communication between the input device 202 and its corresponding actuator 216. For example, such renev ed contact or communication may be physical, or via electrical or mechanical communication, or any combination thereof.

[0044J The system 200 also includes one or more controlLers 226 that. n some ar in conlm!Jfljcatjon.-ith the acwaors 216 and the detcctors 220. The controller 22 is canabi of imerrupting autc'crous control (STEP 116). The co:trol1er 22 e::cutes a vehici:ntr rogra:-i 22, hasei a leasi. in par: o t-control policies 21J.. J: s.: e:di-:, ::-c: 5 is a ii.r3:rc 5-i'-. thr e: :s. i co:::je 225 is a [004!l In anotl-ei-embodie-t. the vehicle conto! p:ogram 22 includes rncdule that pr: ;fdei for autononous vehicle ccnrol 230. In another embodiment. the vehicle control prograni 22 includes a predetermined time delay module 232. In some embodiments, the vehicle control program 228 includes an inhibitor module 234 that prevents autonomous vehicle control. The inhibitor modcle 234 pre ents autonomous vehicle control in the absence of operator intervention (STEP 130).

100461 Other embodiments of a system according to the invention include a shutdown sequence 236 managed by thc controller 226. The shutdown sequence is based at least in part on the disassociation between the input device 202 and its corresponding actuator 216. Typically, the shutdown sequence 236 includes a controlled stop of the vehicle in response to an emergency.

[00471 In brief overview, Figure 3 is a flowchart depicting a method 300 for processing a safety signal in an autonomous vehicle in accordance with an embodiment of the invention. The method includes a step of first identifying one or more input devices in the vehicle (STEP 104).

An input device may be an operator input device that directs at least part of the vehicle (e.g., one or more of a steering wheel, handle, brake pedal, accelerator, or throttle). The input device also may be a device directly or indirectly connecting the operator input device to a controlled element (i.e., the object in the autonomous vehicle ultimately controlled by the operator input device). Generally, an operator input device may be linked to or associated with an input device to control the operation of all or part of the vehicle. For example, the input device can be a drive control. A drive control generally includes a throttle, brake, or accelerator, or any combination thereof. In other embodiments, the input device can be an articulation control. An articulation contrc! gneraliv operates equipment attached to the vehicle. This can include, for example, a control Esed to manipulate a blade on a bulldozer, or a tilling apparatus on a tractor.

[0048 Ne;:t, the method 300 includes the step of proridin-one or more control policies STEP Of, C esnoning t the L;put de-. ire. Generally. the cntrol poliois detr.rmine th v-hich the lfcle operates. inciudin2. for e'arnple. ;vhether the control of the vehicle will or a ccmbfnat:c,j, thereof. In addition to the identfjcatjcn of the inru the in entio:: C!c irrpdes stec o:cidHj one .E.1:e::-niC:e in't'i ce1ces. Ti'e tir:l a:: rnechanc?J e;ice that i'rnmulats the in device. Manipulation occurs b-,-. for e;:an-iole.

pushing, pulling. o turning the npu device, or Ly any conibinatjcn thereof. i result of this i the autonomous control of the vehicle. Furthermore, in an embodiment of the invention, the manipulation of the input device by the actuators allow for a controlled shutdown of the vehicle.

[0049J Following the identification of the input device (STEP 104), providing the control policy (STEP 106), and providing the actuator (STEP 108), an embodiment of the invention includes the step of providing one or more controllers (STEP 302). A controller allows the vehicle to be operated according to programmed instructions and, in some embodiments, with little or no operator intervention. A controller typically includes "intelligence" that allows for any combination of manual or autonomous control of the vehicle. Furthermore, in at least one embodiment of the invention, the controller detects and processes a safety signal, and in another embodiment, the controller detects and processes a stop signal and a non-stop signal (i.e., a signal that indicates a "stop" has not been commanded). The non-stop signal is also represented by the absence of the stop signal.

100501 Next, the method includes the step of providing a first communication link between the controller and each corresponding actuator (STEP 304). In one embodiment of the invention, the first communication link includes a network connection between the controller and each corresponding actuator. The network connection can be part of, for example, a local area network or wide area network. It can be a wired or wireless connection, and may provide access to the Internet. Typically, the network connection is part of a real-time control network that adheres to an industry standard (e.g., the "CAN" open standard). Generally, the first communication link connects, (for example, via a network) the actuators so the vehicle can change modes of operation. In one embodiment, the change in modes of operation is in response to the satèt-. signal. For example, the safety signal may dictate that the vehicle stop rnc i:ig. so he cajr,: .:cds -oJc:ncude one or nore actuators associated with the drive control ::nipiLdi ulC drie ccntrol to stoD the ehicle. Genra!lv, the first corrImuncajcn link is a:: eiect-jc& :::ha:jca, virej vh-!s or srv co::binati-v' thereof c3rnmunca±n be-t:- ::rc:::*-' 1tL:.a':rs. aihii: the first Co rnwjcaio'-link. th includes one or more current loops. A current 1oo is typically e comifljou: v'ired coruectf:;; with electrical current flowing througi it. Components associated with the current loc.p detect or measure this electrical current, doing so directly r indirectly (e.g., by measuring a voltage drop across a resistive element). A variance of the current from an expected value (e.g.. interruption of the current) is generally a signal that the current loop con'eys. In embodiments of the invention, the second communication link conveys a manual mode signal, an autonomous mode signal, or any combination thereof. In yet another embodiment, the second communication link conveys a stop signal, non-stop signal (i.e., the absence of the stop signal), or any combination thereof. Typically, the second communication link is configured as a serial hardwire connection between the actuators. In other words, the second communication link progresses from one actuator to the next sequentially, forming a ring.

100511 Next, an embodiment of the invention includes the step of transmitting the safety signal to each of the plurality of actuators via the first communication link, the second commuiijcation link, or any combination thereof (STEP 308). Generally, this communication may occur in any manner in which data is transmitted from one actuator to another. For example, the communication may be electrical, mechanical, wired, wireless, or any combination thereof. In some embodiments, the safety signal is transmitted in response to operator intervention (STEP 310). For example, an operator may depress an "emergency stop" button that triggers the transmission of the safety signal (STEP 308). In other embodiments, the safety signal is transmitted in response to the output of at least one sensor (STEP 312). This can Occur if a sensor measures an instability in the vehicle, such as if the vehicle was about to overturn. The controller provided (STEP 302) iilterprets the output of the sensor, determines an unsafe condition has developed, and triggers the transmission of the safety signal (STEP 308).

[0052J In some embodiments, the.ehicle enters a safe ode of operation on the detecicn of an enlergency or safti signal that is communicated between the controller and each correc-actuatoi vi& the flrst coniniunication link. In other embodiments the ehicje autonatjciy'.

enters a safe nicd, of operation on the dtctio of an enerncv or saetv signa! that is ccnnt beti' cen ccn-Sc:-actuators ia the second ccnJnunjcat:op!f:ik.

the first conrnlurLication link and second communication un!:. Jn ny casc. the safet': g-a! transmitted to the corresponding actuators, which respond accordingly.

IOO53 Folloviing the tra:-smfssic; othe safetvsigial (STEP 30C) an embodiment of the invention includes the step of manipulating th input device (STEP 314) based at least h part on the corresponding control policy and the safety signal. Generally, the manipulation of the input device (STEP 314) may be the physicci movement of an input device by its corresponding actuator in response to the safety signal to effect a change in vehicle mode of operation. In one embodiment of the invention, the manipulation of the input device (STEP 314) includes initiating a shutdown sequence (STEP 316) to shut down the vehicle. This can occur, for example, in emergency situations where the proper course of action is a controlled, safe, shutdown of the vehicle.

[0054] In some embodiments, the safety signal is transmitted in response to output of th sensors. For example, a sensor may indicate that the vehicle, (for example, a tractor) may be on a collision course with a terrain feature that is an obstacle, such as a rock or ditch. This indication may be in the form of a safety signal. Based at least in part on the safety signal, the controller will become informed of the obstacle, incorporate the proper control policy, and communicate with the associated actuators via the first communication link. The actuators will then manipulate the corresponding input devices accordingly in order to avoid the obstacle.

Such manipulation may result in shutting down the vehicle, or generally a change in the mode of operation of the vehicle in response in part to the safety signal, thus preventing an accident.

9055I As another example, the tilling apparatus in a tractor may need to be stopped because the tractor has reached the end of the plot of land that needs to be tilled. In this situation, it ma-become necessary for th tractor to remain running or in motion but for the tilling apparatus to stop or shut to n. Here, the safety signal may L. generated through operator intervento:, stch s disengaginz the inp:: ic of th tiliin anratus from its associated a:i:tr c:, rnbodimnts. via a sensor indicatin2 the end of tillable land. In the first scenario. crzor i;terention causes he ransmission oTth safet" signaL in sonic mbcdinents. by breaing in the seon corn fo:ji lirJ-:. and. F: accc-iir: i:: r'--. ------device is disengaged or shut off. in the second scenario, the sensor data is p:ocessed by the controller and transmitted in accordance;ith the corresponding control policy, in sonie embodiments, by the first communication link over a network to the actuator corresponding to the tiller input device such that the tiller is disengaged or shut off while thc rcmaining actuators continue to engage their respecti've input devices. In some embodiments, a resu1t is a change in the vehicle mode of operation in response to the processing of the safety signal.

100561 There are other embodiments in which the safety signal is transmitted in response to operator intervention. For example, on the detection of an emergency or safety signal, which may occur when an operator interrupts autonomous operation by depressing the brake, the current loop (an embodiment of the second communication link) is broken, causing an open circuit, and acting as a transmission of the safety signal to the corresponding actuators by the second communication link. The input device will then be manipulated accordingly baed at least in part on the safety signal and the control policy corresponding to that particular input device. The safety signal and corresponding control policy causes the vehicle to operate in manual mode, or autonomous mode, or any combination thereof. Furthermore, in the same example, the safety signal could also be a stop signal, non-stop signal, or any combination thereof, to control the vehicle mode of operation. The vehicle will detect this occurrence and produce an autonomous mode signal, or in the alternative, enter a controlled shutdown mode, thus responding to and processing the safety signal.

100571 In yet other embodiments, the safety signal is transmitted via both the first communication link and the second communication link, thus creating a redundant method for processing the safety signal. Generally, this ensures that the safety signal will be processed properly in the event one of the tvvo communication links becomes inoperative. For example. as previously discussed, if an operator becomes aware of an obstacle and depresses the brake. the resuitng safety sigilai iii be transmitted sejiaft a the second communication liiI: .o all associated aewators. Aditionallv. a senscr mv detect the same obstacle and send. a the contcolier and in acccrdarce with the c:3per control pelic. the safety sina to tie arozte actuatcr a i.'3t conI!: :n:ca:on lin: cid the cbacb. Th:s, in the eei: [OfiSJ Figure 4 is block diagram that depicts a system 400 for processing a safety signal in an autno ehicie ii ccordnce with an embodiment of the inventic:i. Th sjstem 430 typically includ oie o ore iniyit devices 202. An input device may be an operator input device th2t drecs at icast pail. 01 the vehicle (e.g., one or more of a steering wheel. handle, brake pedal. acceleraicr, or thottle). Tl: input device also may be device directly or indireciv connecting the operator input de ice to a controlled element (i.e., the object in the autonomous vehicle ultimateiy controlled by the operator input device) For example, the input device can be a drive control 204. A drive control generally includes a throttle 206, brake 208, accelerator 210, or transmission shifter 211, or any combination thereof. A typical input device 202 is a throttle body (not depicted), which is typically connected to the throttle 206. Other example input devices 202 include a steering gear (not depicted) and tie rods (not depicted). In other embodiments, the input device can include an articulation control 212.

[00591 The system 400 also includes one or more control policies 214 corresponding to the input device 202. Generally, the control policy 214 determines the manner in which the vehicle will operate, typically allowing for vehicle control under autonomous or manual conditions, or a combination thereof. The system 400 also includes one or more actuators 216 associated with the one or more input devices 202. Typically, the actuator 216 includes an electro-mechanjcaj device that drives the input device 202. In one embodiment of the invention, the actuator 216 includes one or more linkages or other mechanical transmissio 218. Generally, the linkage provides the association (e.g., physical connection) between an actuator 216 and the associated input device 202. A typical linkage is a lever and pivot joint, a typical transmission is a rack and pinion device. In one embodiment of the invention, the linkage 218 manipulates an input device 202 in response to the safety signal in accordance with the corresponding control policy 214.

10060J The system 400 also includes one or more controllers 226 that, th some embodiments are !n CT rci'-v ith th att:aors 216. the coroipoiic\ 214, and one ornlore;erisccs 402.

Generaik. the sersor t02 includes any device that is capable of assessing the enviropji:t in an rot:nc the;ehicle for th presence o-ahsencc of hazards or obstacles, as; el as th 0sii0n. cr c:-bDth. of the vehicle. Fzr e:carnc!e. in some enhcdinier's a seJsc is a -.: . O:3! ros:t:c"g s stern. 2: a:' a se::sc-a senso; such as a LDAR system. stereo vis1oi system. infrared vision system. radar system. oi-sonar system. in some embodiments. the contrcie:-226 t:ansmits the safety signal based at least in part on the control policies 214. in some embodiments, the controller 226 is a microprocessor.

In other embodiments, the controller 226 is a microcontroller.

100611 A feature of the system 400 is that it includes a first communication link 406 between the controller 226 and each of the actuators 216. In one embodiment of the invention, the first communication link 406 includes a network connection. Another feature of the system 400 is that it includes a second communication link 408 between each of the plurality of actuators 218.

In one embodiment of the invention, the second communication link 408 includes at least one current loop. In another embodiment of the invention, the second communication link 408 conveys a manual mode signal, an autonomous mode signal, or any combination thereof. In an alternate embodiment of the invention, the second communication link 408 conveys a stop signal, a non-stop signal, or any combination thereof.

[00621 The system 400 also includes a transmitter 404 which, in some embodiments of the invention, transmits the safety signal to at least one of the actuators 216 via the first communication link 406, the second communication link 408, or any combination thereof.

Generally, the transmitter 404 can transmit data, such as the safety signal for example, in any manner in which data is transmitted to the actuators 216. For example, the transmission may be electrical, mechanical, wired, wireless, or any combination thereof. In some embodiments, the safety signal is transmitted in response to operator intervention. In other embodiments, the safety signal is transmitted in response to the output of at least one of the sensors 402.

[00631 In brief over lew, Figure 5 is a flow chart depicting a method 500 for tracking at least one terrain feature by.ir autoncmous vehicle in accordance. ith an embodiment of the invention.

The metiod includes steo of first pros idina oe or more!ocalization sensors (STEP 502k Tl ior:fntiple::hicn isci-s t.pf:a dernnes th çcsticn of the vehicle reia:i. e tc.

one or --ior reference;cints. For exa:-nle, in acme embodiments, the localization sei:acr s::te inoes a pitD snson rii sensor, a\ sensor. conpiss. global positioning system. i:ertial na-iion s:se. cci-::e:. " an c:mbi:a:jc:-t::' By fhsf:g t-e eihe 2LCE ce ocs!.jon sn c:-a:::: can be achieved. For example. in some embodiments. data from the 1obal positioning s-'stem.

odometer, and compass may be fused together to accurately determine the position of the vehicle.

O064J Next. the method 500 includes the step of providing one or more perception sensors (STEP 504). The perception sensor typically assesses the environment about the vehicle. For example, in some embodiments, the perception sensor suite includes a LIDAR system, stereo vision, infrared vision, radar, sonar, or any combination thereof. The ranging and feature data from the suite are fused together in a weighted fashion to build a more accurate representation of the space around the vehicle than can be achieved by using any single sensor alone. Next, embodiments according to the invention detect one or more terrain features about the vehicle (STEP 506). Detection is based at least in part on a change in the output of the perception sensor.

Generally, the perception sensor will indicate the presence of a terrain feature that is a pptential danger or hazard to the vehicle and that the vehicle may need to avoid. For example, the output of the perception sensor may indicate the presence of one or more of a fence, rock, ditch, animal, person, steep incline or decline, or any combination thereof. For example, in some embodiments, this feature may be a dismounted infantry soldier that the vehicle may need to track to perform a simple autonomous mission like following.

[00651 Next, the location of the terrain feature relative to the position of the vehicle is computed (STEP 508). The computation is based at least in part on the output of the localization sensor.

For example, the output of the localization sensor is interpreted to place the vehicle at a point of a coordinate system. The output of the perception sensor is interpreted to place the terrain feature at particular coordinates relative to this point. Computations based on, for example, analytic geometry determine the displacement (i.e., distance and direction) between the terrain feature and the vehicle. For example, for a tractor tilling a field, the localization sensor of a tractor indicates the tractor is at point The perception sensor then indicates the presence of a terrain feature, such as a fence. The location of the fence is then computed relative to pcnt A. Fo exanple. tI:e fence ma be compued as being 100 feet directly in front of the vehicie ocatton itoint A. O:ourse. as the iehile noes, poiit moves as -s tue;eee cc.j 2re: :b e1ic:e:.:s tre:se. In o:her ecis. ve:i:ie "fall off the nisn.' Alternatively. in some embodiments, the origin of the coordinate ssteni may be defined as the instantsneous location cC the vehicle. ineanng that the coord;nate system can represent a roving sub-region of the universe about the vehicle. In this configuration. with the vehicle in motion, terrain features car enter and leave the coordinate systern as they encounter the boundaries of the latler.

[00661 Next, the location(s) of the terrain feature(s) is (are) stored in at Jeast one memory (STEP 510). In some embodiments, a precise determination of a terrain feature's location is required so, for example, the location data includes information to identify the terrain feature's location in three dimensions. Nevertheless, this may require a large amount of memory so, in some embodiments (e.g., where less precision is adequate), three-dimensional location data are mapped to two dimensions and stored accordingly (STEP 512). This generally reduces the amount of memory needed. In certain embodiments, terrain feature data is stored as points within a two dimensional plane. For example, in some embodiments, the system observes the location of the point in three dimensional space. If the point is higher than the top of the vehicle plus a danger buffer zone, then the point is discarded. If the point is within the plane of the ground surface, then the point is discarded. If the point is below the plane of the ground surface, it is retained as a "negative obstacle," i.e., a lack of surface across which to run. If the point is within the z-altitude that the body of the vehicle could pass through, it is stored as a "positive obstacle." Locations with the two-dimensional space that do not have stored points are presumed to be passable. In addition, terrain features may be stored as a point cloud set, whereby discarding three-dimensional points outside the volume of interest significantly reduces the size of the set. In the c!terrativ. terrain feature data ma-;be stored as bits V. ithin a two-dimensional occupancy grid, where the two-dimensiopa! grid is snialer than a three-diniensjona grid by the represented altitude divided by the vertical granularity. For example, in one embodiment, a bo'iide:-or other object cr ten-au: feature may be detected at a location given b-Cartesian coc'rJinate. (: i rel:L--e to:fcn the. ehfce (Tnec s E storing only the:-and v-ccordjntes and not invo!i!: the a-coc.:dinaLs n c:i:e-"ed a::d n:et!:e:i:tica z:-oces i re iren:e-ts are red::ed, (in this e-mle :c:ec*:eser the s::fa:e o:: whfcb the:ehicle tr:::e. a:-the z-coc:n:::- [0067 Tyoica!lv. the ehicle s ir motio; arid the eriain fetnre is stati-:try. The ce c-f t;e invention also!nciLdes the case rhere the ehicle is stationary and the te-rain feature is i:' motion, or the case where both the vehice and terrain feature are in motion. In any case an embodiment of the invention inciudes the step of updating the stored location of the terrain feature as its locaticn changes re!atfve to the vehiclc (STEP 51). Consequently, the vehicle maintains an accurate and dynamic representation of the surrounding terrain and terrain feature.

[00681 In sonic embodiments, updating the stored location (STEP 518) includes recomputing the location of the terrain feature based on changes in the outputs of the localization sensors, perception sensors, or both (STEP 524). Generally, once one of the sensors indicates a change from a previous output, the location is recomputed (STEP 524) and stored in memory, and thus the stored location is updated. In some embodiments, updating the stored location of the terrain feature (STEP 518) is based only on a change in the output of the localization sensor, in4icating a change in the location of the vehicle. For example, the perception sensor may detect a stationary boulder while the vehicle is moving. The movements of the vehicle cause changes in the output of the localization sensor (i.e., the changing output represents the changing location of the vehicle). The outputs of the localization and perception sensors are used to compute a displacement to the terrain feature. Because this displacement is relative to the location of the vehicle, and because the vehicle is moving, updated displacement values are computed during the movement.

[0069J In other embodiments, updating the stored location of the terrain feature (STEP 518) is based only on a change in the output of the perception sensor, indicating a change in the environment about the vehicle, for example the initial detection of a terrain feature or movement of a terrain feature. When the vehicle is stationary and the terrain feature is moving, chan'es in the output of the perception sensor gibe rise to changing displacenent;ak:es.

[CO7 sc-;e ae rcomputing he location of the terrain feature (STEP 24.

the pr.iousl-s:o:ed location fs iscrded from rnen-crv (STEP S.2). pica!!-: to co:-soac.. in one e:or:t te fsc:: occurs aier predeterr-f:'ed ccitjcn is rue: p --i r,'---'i----,---,--r::i-. ._ 1.

* ----.l.-. too distant to represent s hazard to the vehicle. For e:amnle. if a boulder is detected tn meters from the vehicle, but the vehicle is rncving (as detected by the localization sensor) w' fror the boulder, the compuied displacement to the boulder will increase. When, for example, the distance portion of the displacement exceeds fifteen meters, the location of the terrain feature is discarded.

[00711 In another embodiment, the perception sensor is characterized by a persistence.

Generally, a persistence means that the perception sensor must assess the surrounding environment for a period of time before indicating the state of the surrounding environment, in other words, a single detection, based on, for example, on one sweep of the surrounding environment by the perception sensors may, in some embodiments, be insufficient for the perception sensor to indicate the presence of a terrain feature. Accordingly, in some embodiments, accurate detection of a terrain feature requires multiple sweeps by the perception sensor, and detection of thatterrain feature on each sweep. Persistence addresses instances where a terrain feature is intermittent and, therefore, unlikely to represent a hazard. For example, if a bird were to fly quickly in front of the perception sensor, then continue flying away and out of range of the perception sensor, the presence of the bird would not be sensed as a terrain feature because the condition of the persistence was not met, as the bird was detected in too few perception sensor sweeps of the environment about the vehicle.

100721 If the perception sensor suite detects a terrain feature, the location of the terrain feature is stored in memory as discussed above. If one or more subsequent perception sensor sweeps fail to detect the terrain feature, then, in some embodiments, a condition is met that causes the bcation of the terrain feature to be discarded. In other words, if a terrain feature does not "persist" in the field of view the perception sensors suite for a sufficient amount of time, then the terrain feature is dee;:ed not to represent a hazard. and its location is discarded.

E73! Afte: L! ic:a::: :.E'a terrafr!iè::e is teie, one emb-odinien inchdes (he er ajustin the t;'ajectorv f the ehcie ba3ed at least in part on the terrain feature location stored i -e riernor CSTEP 54). This is gener:lly dc:e to so the vehicie avoid.s the terrain features cbstac!es a:-ate:d2:1t:ia: s. Adjustment in the t:aject:r. :r be an: h:nge i -.i::e:. : :aiL3.--j:e -a--=c---3TE 514) includes the step of selecting the preferred trajectory from a plurality of ri:ed alternative trajectci-ies (STEP 516). GcrLer2fly. the plurality of alternative trajectories Izay be possible responses to a terrain feature, and they typically are ranked ir a certain order that indfcates preference. For example. the niost preferred alternative trajectory may be that trajectory that require3 the smallest adjusLment to avoid a collision. Conversely, the 1eas preferred alternative trajectory may require the largest adjustment.

[00741 As an illustrative example, consider the case where a terrain feature is minor in nature, such as a small shrub that is computed to be seventy-five meters in front and two degrees to the left of the vehicle. The selected preferred response may be to adjust the vehicle trajectory by moving one degree to the right causing the vehicle to continue close to the terrain feature while avoiding a collision. Conversely, if the terrain feature is major, such as a cliff located thirty meters directly in front of the vehicle for example, the preferred trajectory may be a 180 degree change in vehicle direction.

[00751 Figure 6 is a block diagram depicting a system 600 for tracking a terrain feature by an autonomous vehicle in accordance with an embodiment of the invention. The system 600 includes a localization sensor suite 602. The localization sensor suite may include a pitch sensor 604, a roll sensor 606, a yaw sensor 608, an inertial navigation system 610, a compass 612, a global positioning system 614, an odometer 616, or any combination thereof. The localization sensor suite 602 generally includes any device or sensor capable at least in part of determining the position or orientation of the autonomous vehicle. The localization sensor suite 602 fuses the data from each sensor in the suite together in a weighted fashion to achieve a more robust estimations of state than is available with any individual sensor by itself. In some embodiments, the localization sensor suite 602 determines the orientation of the vehicle, such as its pitch, roll.

or: n part to nsure that the vehicle is not in danger of tipping over on its side. Ib: enpk iii other c- ix.dimes, .h Ioc.uizaton sensor suite 602 determines the poSitloti oL'Lhe VeiiiciC!fl ad tf:rj to it o:iejt,tjon, stch as the cation of the vehicle or a nlot of land, fcr e::anni.

O0'?5 The s;s.:n isc:ciues a sensor suite 61. The perceDtic:i sens: s*:e o:: aho: -::f:ie a:: ;ene:. i::o:des a LIDA. s-.

combination thereof. The system 600 also includes a detector 220 that detects the presence of all navigationaily significant ten-am features in response to a change in the output cf the perception sensor suite 618. Generally, the detector 220 is typically apparatus or software that correlates the output of the perception sensor suite 618 to the presence or absence of a terrain feature.

[0077J In an alternative embodiment, the perception sensor suite 618 is characterized at least in part by a persistence. Generally, a persistence ensures against a false-positive reading of a potential terrain feature by creating a condition that the terrain feature must remain the perception sensor suite 618 field of view for a particular time, typically for a number of perception sensor sweeps. For example, if a tractor is tilling a plot of land, in addition to permanent terrain features such as, for example, trees, rocks, or fences, the perception sensor suite 618 combined with the detector 220 will also detect objects that briefly enter the environment about the vehicle including, for example, a bird that flies across the field ata relatively low altitude, a ball that is thrown through the environment about the vehicle, debris carried by the wind through this same environment, or other transitory objects. In one embodiment, if a terrain feature does not "persist" in the perception sensor suite 618 field of view for a particular time, then the terrain feature does not represent a hazard to the vehicle.

Typically, the persistence may be defined to increase or decrease the likelihood that transitory objects, such as the examples given above, are characterized and assessed as terrain features.

[00781 The system 600 also includes a controller 226 capable of computing the location of at least one terrain feature relative to the position of the vehicle and based at least in part on the output of the localization sensor suite 602. In some embodiments, the controller 226 includes a microprocessor. In other embodiments, the controller 226 includes a microcontroller. Generally, once the detector 220 has detected a terrain feature based at least in part on a change in prceptior sensor suite 618 output, the controller 226, in communication with the detector 220.

tc Wscance to the tel-i-am èatLtre relative to the vehicle based on th outpul of the Iccalization sensor suite 602. For exanple, the presence of a fence on a plot of land causes a change in perception snso!-suite 618 outDut. such that detector 220 detects the fence as a terain fear. The 1caizaton s::sz sit O2 cutput indicates that the vehicle is CU:Te1: -1-_:--1--_ ------ ------------ ---. -__&__L___ - a' a --. -- [0079J The system 60C also includes a me:rory 632 for storing the location of ore or n-iore terrain features. Th mem'x-can be \claLile (e.g.. SRAM. DRAJvI) ornonvc.!atile (e.g.. ROJ'.'i FLASH, maetic (diEi:). ootical (dial:;). n an alternative embodiment, the stored location of 2 terrain feature in nemo;; 632 i:cluds a n-aped two-dimensional representation of a three densi3'J represetatic: 6J. Genra!ly. in some embodiments, the mapped two-dimensional representation includes any two coordinate points that identify the distance of a terrain feature relative to the vehicle. The two-dimensional representation typically provides less precision. but requires less memory and computational power to maintain or update. The reduced precision compared to a three-dimenaonal representation may be adequate in certain applications.

[00801 In some embodiments, the stored location of a terrain feature is based on a change in the output of the localization sensor suite 602. Generally, if a terrain feature is stationary but the vehicle is in motion, the localization sensor suite 602 output changes to reflect the motign of the vehicle. The controller 226 then determines the displacement between the terrain feature and the new vehicle location, and this new displacement is stored in memory 632. Therefore, in this embodiment, the stored location is based on a change in localization sensor suite 602 output.

[00811 In other embodiments, the stored location of a terrain feature is based on a change in the output of the perception sensor suite 618. For example, if a terrain feature such as a cow begins moving towards the operating vehicle (e.g., a tractor), the perception sensor suite 618 output will indicate this change in the environment about the vehicle. The detector 220 will detect this change in output and the controller 226 will compute the location of the terrain feature relative to the vehicle. This new displacement will then be stored in memory 632 based on the change in perception sensor suite 618 output caused, in this example, by the movement of the cow.

[0082l In an alterrati e enodiment. te systen 60C) also includes logic 636 for discard jni the stored locatEcn based a lest in part on;!Sf-Vm at least one nredeternijn& condtjp Gen-all-;, th eej-;--:onitic: r-:y fn!:;de an; use:--dened te:-ms, events c- _:- inati')n t recfit rnus cccr or ce in e:istence before discarding the terrain fat:res ::; o:-2. I: :-et ano';e: e:cdj:nent tie ndetern:jied condjtjor!des a::---dl: aceri:e-: t;'ee: t:e iocac:: of the:.r's:: feat'e:.. : predetermined dislacemnt Value of fifteen meters rearward of the vehicle, a te:Tah-' featt're is detected ten meters directly south of the vehicle. aid the vehicle is moving north. The location of this teiTain feature is stored in memory because it is within (i.e., closer to the vehicle than) the fifteen meter rearward predetermined displacement. Continuing v'ith the example, as time progresses. ihe chicle mces such that the terrain feature is over fifteen meters behind the vehicle. At this point, the location of the terrain feature will, in this embodiment, be deleted from memory (32 and not be stored in memory 632 unless the object once again comes within the predetermined displacement value.

10083] In yet another embodiment, the logic 636 discards the stored location when the predetermined condition includes failing to detect continuously the terrain feature for a sufficient amount of time (e.g., the terrain feature does not "persist" in the field of view the perception sensors for a sufficient number of sweeps). For example, the predetermined condition riay be that the perception sensor suite 618 indicates that a terrain feature is greater than a certain distance, for example fifty meters, from the vehicle, and the persistence generally ensures that the perception sensor suite 618 repeatedly over a period of time sweeps through the enviromnent about the vehicle, senses the presence of the terrain feature. In such a case, a single indication that the terrain feature that was once forty-nine meters from the vehicle is now more than fifty meters from the vehicle may be insufficient to cause the stored location to be discarded from memory 632 because the persistence has not been satisfied. However, multiple indications over a period of time, or multiple sweeps by the perception sensor suite 618 that all indicate that the terrain feature may satisfy the predetermined condition, (i.e., is greater than fifty meters from the vehicle) and may also satis' the persistence, therefore in this case the terrain feature location will be discarded from memory 632.

100841 hi another embodiment, the s3.stenl 600 includes adjust!-nent logic 638 for adjusting [he :aect-. fth;e:Ie I5C Ifl parL ih. location of one or more LeFt-am features stored it-. memory 632. Ceneraiv, adjustnei loic 638 flay alkr the direcior1 Cr raieeto:--the &iCl;d ma-' fncLtd any:h:n in the vhice df:-ectfct-, :iade ofc rator Cr ar :3n'i::a:ic: tere: F:r:::;, ifa k-i.-fe:nre is Etc:-e fi:ne::::v f32:s:f - -*_1. --.-= *-:---=-----.

vehicle. In some embodiments. the diustmnt logic 638 includes a selector 640 for selectk.

one preferred ra:ecto:7 froi a puralit' of ranied cJternati'e trajectories. Ic continue v.rith t'ie immediately preceding example. i1 response to a terrain feature twenty meters in front cfthe vehicle, the selecior may for e::ample have the options of entering a controlled shutdown. tirning left five degrees, left ten degrees. right F!ve degrees, right ten degrees, or turning around 1 0 degrees. In one embodiment, the alternative trajectory of turning the vehicle to the left five degrees may be the most desirable and thus highest ranked of all alternative trajectories.

Therefore, the selector 640 selects this option to be executed by the vehicle.

[0085J In brief overview, Figure 7 is a flowchart depicting a method 700 for behavior based control of a vehicle in accordance with an embodiment of the invention. The method includes the step of first identifying one or more input devices in the vehicle (STEP 104). An input device may be an operator input device that directs at least part of the vehicle (e.g., one or more of a steering wheel, handle, brake pedal, accelerator, or throttle). The input device also may be a device directly or indirectly connecting the operator input device to a controlled element (i.e., the object in the autonomous vehicle ultimately controlled by the operator input device). For example, the input device can be a drive control. A drive control generally includes a throttle, brake, accelerator, or any combination thereof. A typical input device is a throttle body, which is typically connected to the throttle 206. Other example input devices include a steering gear and tie rods. In other embodiments, the input device can be an articulation control. An articulation control generally operates equipment attached to the vehicle. This can include, for example, a control used to manipulate a blade on a bulldozer, or a tilling apparatus on a tractor.

[OO6J Next, the method 700 includes the step of providing one or more actuators (STEP 108) associated with one or more input devices. The actuator is typically an electro-mechanjcaj device that o:ipu1ates the input devices. Manipulation occurs by, for example, pushing, LUi_. LLiLL Lne 1LpuL ceices. or by aijv comolnauon thereof. .\ rcu!t or this is ie -ci coi::roi of the ei;i:ie. Gneraih, the presence of actuators in the vehic'e Joe:o peratic of the cc--spondn li:ut de ices.

st) cffdotify: the i:io: oe. ices(STE it}. a::d rocfc-I.:. :n.so -L-i i & i:!L-!:1 of co::i.

modes (STEP 702) associated with the actt'ators. Each mode allows the "ehicle tc h cre:c.te in a separate arid distinct fashion. Each mode may also include a plurality of beha-iors. Each behavior typically is separate program that proposes an action set to the vehicle's behavicr arbiter. In some embodiments, the step of defining a plurality of operational modes (STEp 702) includes defining a manned operation mode (STEP 704). a remote unmanned iele-operaticn mode (STEP 706), an assisted remote tele-operation mode (STEP 708), an autonomous unmanned operation mode (STEP 710), or any combination thereof. Autonomous unmanned operation mode (STEP 710) is the state where the ehicle is performing a prescribed task with little or no operator intervention. The vehicle modifies its actions to compensate for terrain features that may be obstacles and other hazards. In contrast, the manned operation mode (STEP 704) overrides autonomous control of the vehicle and allows an operator to control the vehicle.

The two tele-operational modes (STEP 706 and STEP 708) are the states where the unmanned vehicle is being operated from a remote location by a dismounted operator or by an opeiator in a chase vehicle.

[00881 Next, some embodiments of the invention include the step of defining at least one action set (STEP 711). An action set is typically characterized at least in part by a priority and each action set generally includes a plurality of alternative actions that are ranked according to a corresponding plurality of preferences.

(00891 Next, in an embodiment of the invention, an arbiter or arbiters that are associated with the actuator are provided (STEP 714). An arbiter selects the action set having the highest corresponding priority (STEP 713). The arbiter also selects the alternative action from the selected action set having the highest preference (STEP 712). In some embodiments, he selection of the alternative action (STEP 712) includes the selection of a trajectory set (STEP 715). trajectory set is typically a series of alternative navigatiofl ccmrnands that orescrihe the .hecton r rate oEra'ei (i.e.. transiauonal and rotational iociv. For e'arpk to trraii; fe.tu-U. other hazard, the hicie riray change its speed. direction, or both. in ar'-i::: degrees. Tc aoco: lish this, the vehicie;ray slow slia:t!y c:d t:" sii:t. i: ma ac r:act:'. \:cie s::!t\). 2'ej-:, 100901 Next, in some embodiments, the arbiter modifies the selected action set (STEP 718).

typically by modifying one or more of the alternative actions contained in the selected action set.

Modification generally entails tailoring the chosen action to the particular situation such that the vehicle then executes the modified chosen action. For example, for the selected trajectory set, the arbiter can reduce the vehicle velocity along the arc of travel. To illustrate, consider the case where a tractor is tilling a field under autonomous operation. Assume that an obstacle, such as a tree, is detected in the path of the tractor, but still at a safe distance ahead of the tractor. At this point, there are several potential behaviors available to the vehicle. Some of the possibilities include for the tractor to remain in autonomous operation, or switch to manual operation or safety operation. Staying with this representative example, it is typically within the ability of the tractor to avoid a static object, such as a tree, while in autonomous control. In this example, the arbiter examines the available alternative action sets (i.e., alternative trajectory sets that will keep the tractor from encountering the tree). The arbiter then selects the highest priority actidn set (e.g., the trajectory set requiring the least amount of change relative to the intended path of the vehicle).

[00911 In some embodiments, the arbiter modifies the selected action set (STEP 718), typically in response to other data. The data may include information received from sensors (STEP 720), such as the localization sensor suite 602, or the perception sensor suite 618, or both. In some embodiments, the data may include a constraint on actions. This constraint may include a command that the selected trajectory set not allow vehicle movement in a certain direction, or at a certain speed. In some embodiments, the selected action set may include a restriction set for implementing the constraint on the action set. Generally, the constraint defines an in]pei-missjbie area of vehicle operation. The data may also include information received from the vehicle's resident local terrain feature map (STEP 722). In other words, the selected trajectory set provides a baseline alternati'e trajectory for the vehicle, but arbiter can modify this baseline tc con-inensate for variations i the environn-ent around the vehicle. Whf!e th baseline trjector-may be adequate in some circumstances, the presence cf. for example. other terrain features or hazards a!e the baseline trajector-. is gener.llv unacceptable. Th arbiter interates iforatic' rc,ved frcn-i Sn5Ors and n:ap data to ensure that the ehic1e cn adhere to baseline sei-e Z:aeco:-. :t-i0021 in some e bodirnerts er the)te-native actici with the igh3t nreferece hs heen selected, an embodiment o'the invention operates the input device in ccordance iLh the selected alternative rcticn (STEP 726). In some embodiments, the action set may be modified (STEP 718) before operating the input device in accordance with the selected alternative action (STEP 726). Generall. once the 2rbiter hc.s selected an alternative action (STEP 712) from the selected action set and modified (STEP 718) the selected action set, the input device is then operated in accordance %ith that action. For example, if the selected alternative action is a safety operation, such as a controlled shutdown of the tilling apparatus on a tractor, and the arbiter modifies this alternative action by allowing background operations, such as the localization sensors to continue running, the input device associated with the tilling apparatus will be commanded to shut down, but the localization sensors will continue to operate normally in a manner consistent with the selected alternative action.

100931 Figure 8 is a block diagram depicting a system 800 for behavior based control of a vehicle in accordance with an embodiment of the invention. As in the other Figures, the interconnections depicted in Figure 8 represent various communication paths between the enumerated objects. The system 800 typically includes one or more input devices 202. An input device may be an operator input device that directs at least part of the vehicle (e.g., one or more of a steering wheel, handle, brake pedal, accelerator, or throttle). The input device also may be a device directly or indirectly connecting the operator input device to a controlled element (i.e., the object in the autonomous vehicle ultimately controlled by the operator input device). For example, the input device can be a drive control 204. A drive control generally includes a throttle 206, :e 20g. acc!erator 210, or tra1smissjon shifter 211, or any combination thereof.

A tynical ii;L!t device 202 is a throttle body (rot depicted), hich is typically connected to the thr.ott!e 206. Cther e'anple input devices 202 include a steering gear (not depicted) and tie rods (nat depirted). In otic: embodiments, the input de ice includes an articulation control 212.

100941 The s 00 Usc nchides cne or nc: actuators 216 associated ith the cn inpt devic 02. Thrfc!iv, te ac:tor 216 iclues a: eiect:c-n:echa:i-! de\ ic dri ice 2' F:: e::ic: :-- 2.

(e.g.. ohysical con'etioi) het'eep an actuacr 216 and the asscciated input device 202.

typical linkage is a lever id piot joint, a typical transmission is a rack and pinion device.

[O95! The system SOC also includes a plurality ocbehaviors 802 associated with the actuJor 216, where each behavior 802 includes at least one action set 805 ranked according tc a corresponding plurality of priorities, and each action set 805 includes a plurality of alternative actions 804 ranked according to a corresponding plurality of preferences. The system 800 also includes at least one arbiter 8i6 associated with the actuator 216 for selecting the action set 805 having the highest corresponding priority and for selecting the alternative action 804 having the highest corresponding preference within the selected action set 805. In some embodiments the arbiter 816 modifies the selected alternative action 804. Generally, the arbiter is software, hardware, or a combination thereof.

10096] The different modes of vehicle operation generally contain a plurality of behavkfs. For example, in some embodiments, the modes include a remote unmanned tele-operation mode 806, a manned operation mode 808, an autonomous unmanned operation mode 810, assisted remote tele-operation mode 812, or any combination thereof. These modes each generally correspond to different vehicle missions. For example, the manned operation mode 808 may dictate that only the operator may control the vehicle, whereas autonomous unmanned operation mode 810 would generally be a behavior where the vehicle needs little or no operator intervention. The remote unmanned tele-operation mode 806 and assisted remote tele-operations mode 812 are the states where the unmanned vehicle is being operated from a remote location by a dismounted operator or by an operator in a chase vehicle. In some embodiments, the plurality of alternative actions 804 of an action set 805 include a trajectory set 814. Generally, the trajectory set 814 includes a plurality of possible trajectories, or paths. that the vehicle may follcw. For example, a trajectory set 814 represents the possible paths of vehicle motion with each path being one degree ciockise from the previous trajectory path. In some embodiments, the vehicie modL'es he siec ted action to oi a terrai:: feat LIr.

0097J A&fionall. n sc*.:i er.bojn-s. the svste: 500 nav inchzd at!e:s::-S2 for stj: rtc!: G:z!-e ice. rcacaI!oc:-v co:ibirtjop thereof. Gener!!y. the djustr 20 will cdjst the speed or directin. or both.

of the vehicle so it follows its designated trajectory or avoids an cbstacle.

100981 A lui-ality of prioiitis deeniiliies the ranking ol the plurality of alternative actions.

Generally, the most impc-fan actio'is for safe vehicle operation will be given the highest priority. For example, if there is a boulder 100 meters in front of the vehicle, and a group of people five yards in front of the vehicle, within an action set 805 there will be one alternative action 804 for avoiding the boulder, for example a slight adjustment in the vehicle rotational velocity, which would be an autonomous unmanned operation 810, appropriately modified.

There may be another alternative action 804 for avoiding the group of people, for example a controlled emergency shutdown. Here, from within action set 805 the alternative action 804 with the highest corresponding preference would be given to the safety operation due to the more immediate nature of the threat. The priority can for example be determined from the ditance to the terrain feature(s).

(0099] The maximum vehicle speed and correspondingly its maximum deceleration speed can be linked to the amount and density of navigationally significant terrain features in the local vicinity of the vehicle. The vehicle will limit its speed so it only requires a configurable fraction of the maximum deceleration rate of the vehicle to come to a complete stop while still safely avoiding all obstacles. The planned fraction of the deceleration rate is typically used to control the fraction of the vehicle's performance envelope used when avoiding obstacles. This provides a configuration for providing safety margins and for tuning the smoothness of the control of the vehicle.

[001001 The system 800 also includes one or more controllers 226 that, in sonic embodiments.

are in communication with the input devices 202 and the arbiter 816 so the controller 226 operates the hitt de ices 202 in accordance with the selected alternative actior. 804. 1:: :bcd:nts Lh sclected aiLernaue action 804 may be modified. In son embcdirnent. ihe controller 226 is a microprocessor. In other embodiments, the controller 226 is a rnicrcoritro!Icr. For e:;rnole. if the alternative action 804 selected by the arbiter 816 clis fcr the hicle tc rn n:a!n autonc-coeratjori v.!ile dec-easjn i:s sneed b tri nerce:-i::.z ief, L -ave ciegi-ces. .ie CcrEoi!er 226 \!! ccntrc: Ee act.:atcrs 2iE asso:iaec with the input de"ices 202, such as the drive control 204 to change the ehicIe sneed. arid steeiing wheel to chang. the vehicle direction.

[001011 in sonic embodimc:ns ofhe invention, the system 800 also includes a localization sensor suite 602. a perception sensor suite 618, a local vehicle centric terrain map 818 or any combination thereof. Typically, the localization sensor suite 602 may include one or more of a pitch sensor 604. roll sensor 606 yav sensor 608, inertial navigation system 610, compass 612, global positioning system 614, odometer 616, or any combination thereof. The localization sensor suite 602 is generally responsible for fusing the data from multiple sensors together in a weighted fashion to develop a superior estimate of the position of the vehicle. Typically, the perception sensor suite 618 may include one or more of a LIDAR system 620, stereo vision system 622, infrared vision system 624, radar system 628, sonar system 630, or any combination thereof. The perception sensor suite 618 typically assesses the environment about the vçhicle and is generally responsible for fusing thedata from multiple perception sensors together in a weighted fashion to develop a more accurate description of the navigationally significant terrain features in the local environment about the vehicle. The terrain map 818 generally is a compilation of all terrain features detected within the environment about the vehicle. For example, the terrain map 818 may indicate that there is a steep incline twenty meters directly to the left of the vehicle, and a tree 100 meters in front by twenty meters to the right of the vehicle.

[00102j In brief overview, Figure 9 is a flowchart depicting a method 900 for selective control of a vehicle in accordance with an embodiment of the invention. The method includes a step of identifying one or more input devices in the vehicle (STEP 104). An input device may be an operator inpuL device that directs at least part of the vehicle (e.g., one or more of a steering wheel, handle, brake pedal, accelerator, or throttle). The input device also may be a device directly or indirectly connecting the operator input device to a controlled element (i.e.. the objeot t;-icaiou. hiJe Limtel controlled by the opefator input device). For exmplc. the input device can be a drivc control. A dr control generally includes a throttle, brake, or .ccelertcr. any conbination thereof. A typical input device is a throttle body. vhicli is cdi!' ccnected to the thcc. the: e:-z:mpie input devices incdc a st:-h-a -.--: control generally operates equipment attached to the vehicle. This can include, for x2np!e. a control used to manipulate a blade on a bulldozer, or a tilling apparatus on a tractor.

[00103J hi addition to the identification of the input devices (STEP 104), the inventjo also includes the step of providing one or more actuators (STEP 108) associated with one or more input devices. The actuator is typically an electro-mechanical device that manipulates the input device. Manipulation occurs by, for example, pushing, pulling, or turning the input device, or by any combination thereof. A result of this is the autonomous control of the vehicle. Furthermore, in an embodiment of the invention, the actuators still allow manual operation of the vehicle. In other words, the presence of actuators in the vehicle does not preclude manual operation of the corresponding input devices. In some embodiments, a linkage or other mechanical transmission associates the actuator with the corresponding control surface. A linkage is generally any apparatus that facilitates any connection between the input device and the actuator. A typical linkage is a lever and pivot joint, a typical transmission is a rack and pinion device.

[001 04J Next, a plurality of operational modes associated with the actuator are defined (STEP 702). Generally, these operational modes may be defined to include manned operation (STEP 704), remote unmanned tele-operation (STEP 706), assisted remote tele-operation (STEP 708), autonomous unmanned operation (STEP 710), or any combination thereof.

[001 Os] Next, the vehicle receives at least one mode select command (STEP 902). Generally, the mode select commands dictate the operation of the vehicle. In some embodiments, this includes receiving an autonomous operation command (STEP 912). In this case, the actuator manipulates the input device (STEP 314) in accordance with i) the task ihe vehicle is performing, and (ii) at least one of the associated behaviors.

[00106J n another embodiment, receiving the mode select command (STEP 902) i:c!udes in remote command (STEt' 914). Generally, this allows for rernote_controI1e ope:aticn of the vehicle, i.e.. the case her an operator maintains control over the vehicle hen iot physical! present in the.ehicle. Here, vehicle contr1 tyDica!i is not autonomous, but there is :c:lsz3cfation he. cer the acuatc:s:nc the inp.it c!. ices bee iuse the assc f:tior :3u:. :"-- [00i07J In another er-iodjment. receivjna the niode select conmard (STEP 902 inclue receiving a inanua ope:ac; conima'd (STEP 904). In this cace, the siep of n1a'ipulati; the input device (STEp 314) my include the step of disassociating the actuator from the input device (STEP 90(5). or exanpie. after receiving of the manual operation command (STEP 904), Lne actuato-ypicaiiy decoulies from the corresponding drive control. This allows an operatc.r to work the drive control without resistance from the actuator. In other embodiments, after disassociating the actuator (STEP 906), the actuator is reassociated with the input device (STEP 908). For example, this may occur when a vehicle operating manually (i.e., with a disassociated actuator) reverts to autonomous control. In such a case, the actuator must reassocjate with the input device to resume autonomous control of the input device. in an another embodiment, the step of reassociating the actuator (STEP 908) occurs after a predetermined delay (STEP 910).

For example, such a delay can be implemented as a safety precaution to ensure that the vehicle does not revert prematurely or falsely to autonomous control.

[00108] In yet another embodiment, receiving the mode select command (STEP 902) includes receiving a semi-autonomous command (STEP 916). In this case, the step of manipulating the input device (STEP 314) includes operating the input device in accordance with (i) one or more of the plurality of behaviors, and (ii) at least one remote transmission. Generally, the semi-autonomous command (STEP 916) allows autonomous operation of certain features of the vehicle in combination with operator control of other features. The operator is typically, although not necessarily, located away from the vehicle. For example, a tractor may follow a path or pattern prescribed and controlled by an operator. During traversal of the path or pattern, the tractor may encounter one or more terrain features that are obstacles. It is likely that the operatcr would not see these terrain features if the operator is net present ir the ehicle.

Conseqien!v. it is advantageous that the hicle compensate for the presence of the terrain tur2s ith:t uiring cp-ator int:-VenLjon. The vehicle accomplishes this by relying on c5t:c1 vcf:e behavior that runs H concert the s -a2tonc.n-cL's corr.n-iand;rick.

The hici; rr, frr enple. tonon-.: sl alter its zrajectcry, cr speed. or both to a-oid th ___1-,-.- --tvi1c:! ::c one or more input devices 202. An inut device may be an operator input devf e that cects at least part of the vehicle (e.g.. one or nicre of a steering vihe1. handle. brake pedal. accele;-ator.

or throttle). Th input device also may be a device directly or indirectly connecting the ope;-:tor input device to a controlled element (i.e., the object in the autonomous vehicle ultimately controlled by th operator input de ice). For e;ample, the control surface can be a drie control 204. A drive control generally includes a throttle 206, brake 208, accelerator 210, transmission shifter 211, or any co:rbinationthei-eof. A typical input device 202 is a throttle body (not depicted), which is typically connected to the throttle 206. Other example input devices 202 include a steering gear (not deoicted) and tie rods (not depicted). In other embodiments, the input device can include an articulation control 212.

1001101 The system 1000 also includes one or more actuators 216 associated with the input devices 202. Typically, the actuator 216 includes an electro-mechanjcal device that dries the input device 202. In one embodiment of the invention, the actuator 216 includes one or more linkages or other mechanical transmissions 218. Generally, a linkage provides the association (e.g., physical connection) between an actuator 216 and the associated input device 202. A typical linkage is a lever and pivot joint, a typical transmission is a rack and pinion device.

1001111 The system 1000 also includes a plurality of behaviors 802 associated with the actuator 216. Generally, the behaviors are specific programs that propose an action to an arbiter.

The vehicles resident arbiter(s) decide(s) which behavior is expressed based on mission priorities and sensor data. Each behavior 802 typically represents a specific recognizable action the vehicle might take. In some embodiments, the behaviors 802 include terrain feature avoidance 1002. The behaviors 802 and the terrain feature avoidance i 002 are typically software routines, but they may also include hardware configured to perform the required task.

r001121 In scme e XdirL1CIICS. ne system iOO() also nckdes are!eat one recci' er 1004:: re:&'j: a least c: co::i:j an! a lear oie ccntrc!e--26 iti: the roi e: The ccnt:ole 226 e:ecuLes a vehicie procram 22 in a:corance vith tii:ei: cc ma:s. Fof ex.nle. i1c: Conina:d is to eme: a ccntrolled emergency :ef-. )04:is tc the co::.::ier 22g. The::cye 22$ -e:::'. - :: ::e C:_:;:e: t: coran-iand ma" inchde a manu2! cpe:-atjn command that allo-is an cperato-to ssunie control ci the vehicle. In this case. the vehic1. control program includes an inhibitor 234 for dIsassoc!ttng the actuator 216 fioni the input device 202, thereby freeing the latter for operator control.

Generally, in some embodiments, the inhibitor prohibits resassociatjon of the actuator 216 with the input device 202 to ensure that the system remains under manual control. In other embodiments, the vehicle control program 228 includes a predetermined time delay 232.

Generally, the time delay prevents premature changes from one mode of operation to another.

For example, the operator may relinquish manual control to allow the reestablishment of autonomous control. The reestablishment may be substantially instantaneous or occur after the predetermined delay. This delay helps prevent a premature or false return to autonomous control.

tOOl 13J In other embodiments, the operator command may include an autonomous operation command, or a semi-autonomous operation command, or both. In each case, the vehicle control program 228 includes a vehicle control module 1006 that, in cooperation with the controller 226, provides instructions that control vehicle operation. The vehicle control module 1006 typically includes one or more software routines, but it may also include hardware configured to control the vehicle. In particular, the vehicle control module 1006 typically communicates with the receiver 1004 to receive commands sent to the vehicle. These received commands are typically remote transmissions, e.g., sent by an operator who is not in the vehicle. After receiving the semi-autonomous operation command, the vehicle control module 1006 typically allows the manual operation of vehicle input devices, features, or functions, but retains the autonomous control of certain aspects of the vehicle. For example, a tractor may have its speed and direction controlled via remote transmission. If an terrain feature that is an obstacle arises in the path of the vehicle, the vehcle compensates for the presence of the obstacle without requiring operator intcrventi3n, tpicallv by rel-yin on an obstacle avoidance behavior that runs in concert v;ith the sem-auto.t:c 109114] N:te that in Figures 1 through 10 the ent!merated iters re shov..n as indi\ idua of the inventic-j. hoveej-. the may be insearabje i:: ::ente H 2:f:-e Jat::i cdie. i an i:;:r t-: includes a program storage medium. The program storage medium inck'des data signals embodied one or more of a carrier v:ave. a computer disk (magnetic. or optical (e.g.. CD o: DVD), or both), non-volatile memcry, tape. a system memory. and a computer hard dri e.

1001 15J From the foregoing, it will be appreciated that the systems and methods provided by the invention afford a simple and effective way to safely control a vehicle so the vehicle performs its predetermined tasks such as for example removing an operator from harm's way during a dangerous application, or for example to offer direct labor costs savings in commercial applications, in an cfficiert manner.

[00116J One skilled in the art will realize the invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The foregoing embodiments are therefore to be considered in all respects illustrative rather than limiting of the invention described herein. Scope of the invention is thus indicated by the appended claims, rather than by the foregoing description, and all changes that come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

[00117J What is claimed is:

Claims

CLAIMS

I. A method for control of a %ehicle. the method comprising the steps of identifying at least one input device in the vehicle; providing at least one actuator associated with the at least one input device: and controlling the vehicle based at least in part on a selective scheme, the selective scheme comprising: defining a plurality' of behaviors associated with the at least one actuator: receiving at least one mode select command: and manipulating the at least one input device in accordance with the at least one mode select command.

2. A method as claimed in claim I. wherein the mode select command comprises a manned operation command and the step of manipulating the at least one input device comprises disassociating the at least one actuator from the at least one input de' ice.

3. A method as claimed in claim
2. further comprising the step of reassociating the at least one actuator itli the at least one input deice.

4. A method as claimed in claim 2. further comprising the step ofreassociating the at least one actuator ith the at least one input de ice after at least one predetermined dela.

5. A method as claimed in claim 1. herein the mode select command comprises an autonomous unmanned operation command and the step of manipulating the at least one input de ice comprises operating the at least one input de ice in accordance ith at least one of the pluralit of behaiors.

6. A method as claimed in claim 1. wherein the mode select command comprises a remote unmanned tele-operation command and the step of manipulating the at least one input de ice comprises operating the at least one input device in accordance ith at least one remote transmission.

7. A method as claimed in claim I, wherein the mode select command comprises an assisted remote tele-operation command and the step of manipulating the at least one input device comprises operating the at least one input device in accordance with (I) at least one of the plurality of behaviors. and (ii) at least one remote transmission.

8. A method as claimed in claim 7. viherein the at least one of the plurality of behaviors comprises obstacle avoidance.

9. A system for control of a vehicle, the system comprising: means for controlling the vehicle: means for actuating the ehicle control means: means for defining a plurality of behaviors associated vith the actuating means: means for recei ing at least one mode select command: and means for manipulating the ehicle control means in accordance vith the at least one mode select command.

10. A s stem as claimed in claim 9. herein the mode select command comprises a manned operation command and the manipulation means comprises an inhibitor for disassociating the actuating means from the chicle control means.

II. A s stem as claimed in claim 9. wherein the chicle control means comprises at least one predetermined dela).

12. A system as claimed in claim 9. herein the mode select command comprises an autonomous unmanned operation command and the manipulation means comprises at least one of the plurality of behaviors.

13. A system as claimed in claim 9. herein the mode select command comprises a remote unmanned tele-operation command and the manipulation means comprises at least one remote transmission.

14. A system as claimed in claim 9. wherein the mode select command comprises an assisted remote tele-operation command and the manipulation means comprises at least one of the plurality' of behaviors and at least one remote transmission.

15. A system as claimed in claim 14, wherein the at least one of the plurality of behaviors comprises obstacle avoidance.

16. A system as claimed in any of claims 9 to 15, further comprising means for controlling the ehicle based at least in part on a selectie controller, said selective controller comprising: means for detining a plurality of behaviors associated with the actuating means: means for recei ing at least one mode select command: and means for manipulating the ehicle control means in accordance with the at least one mode select command.

17. A sstem as claimed in an of claims 9 to 15 herein the means for manipulating the ehicle control means does so by the controlling means in accordance ith the at least one mode select command.

18. A method for control of a ehicle. the method comprising the steps of: identifying at least one input de ice in the chicle: pros iding at least one actuator associated I., 4-, .itli the at least one input device: and controlling the vehicle based at least in part on at least one of an interruptible autonomous scheme. a behavior based autonomous scheme, a selecti e scheme, and a safet scheme.

19. The method of claim 18. wherein the interruptible autonomous scheme comprises: providing at least one control policy corresponding to the at least one input device; detecting at least one disassociation between the at least one input device and the at least one actuator: interrupting autonomous control of the vehicle based at least in part on the at least one disassociation; detecting at least one restored association between the at least one input device and the at least one actuator; and establishing a revised vehicle control based at least in part on the at least one restored association and the at least one control policy.

20. The method of claim 19 wherein the at least one actuator is associated with the at least one input device by at least one mechanical transmission therebetween.

21. The method of claim 19 wherein the disassociation comprises a separation between the at least one input device and the at least one actuator.

22. The method of claim 19 wherein the step of detecting the at least one disassociation comprises measuring a response of at least one of a proximity sensor and a strain gauge.

23. The method of claim 19 wherein the step of interrupting autonomous control comprises allowing manual chicle control.

24. The method of claim 19 herein the step of detecting at least one restored association comprises measuring a response of' at least one of' a proxinlit) sensor and a strain gauge.

25. The method of claim 19 wherein the step of establishing a reised ehicle control comprises restoring autonomous ehicle control.

26. The method of claim 25 wherein restoring autonomous ehic1e control occurs after at least one predetermined delay.

27. The method of claim 19 wherein the step of establishing a revised vehicle control comprises preventing further autonomous vehicle control.

28. The method of claim 19 wherein the step of establishing a revised vehicle control comprises preventing further autonomous vehicle control in the absence of at least one operator intervention.

29. The method of claim 19 wherein the input device comprises a drive control.

30. The method of claim 29 wherein the drive control comprises at least one of a throttle, brake, transmission shifter, and an accelerator.

31. l'he method of claim 19 herein the input device comprises an articulation control.

32. The method of claim 1 8. herein the interruptible autonomous scheme comprises: detecting at least one disassociation beleen the at least one input device and the at least one actuator: and initiating a shutdown sequence based at least in part oii the disassociation between the at least one input de ice and the at least one actuator.

33. The method of claim 1 8. herein the beha ior based autonomous scheme comprises: pros iding at least one arbiter associated with the at least one actuator: defining a pluralit ofheha iors associated with the at least one actuator. defining at least one action set, each action set characterized at least in part by a priority and comprising a plurality of a1ternatie actions ranked according to a corresponding plurality of preferences; selecting.

by the at least one arbiter, the action set having the highest corresponding priority: selecting, by the at least one arbiter. from the selected action set. of the alternative action haing the highest corresponding preference: and operating the at least one input device in accordance with the selected alternative action: wherein each of the behaiors implements at least one of (i) a providing the at least one action set, and (ii) a modifying at least a portion of the selected action set.

34. The method of claim 31 wherein the input device comprises an operator input device.

35. The method of claim 31 wherein the plurality of behaviors comprises manned operation. remote unmanned tale-operation. assisted remote taleoperation. and autonomous unmanned operation.

36. The method of claim 31 herein the plurality of alternatie actions comprises at least one trajectory set.

37. The method of claim 31 wherein the step of modiIing at least a portion of the selected action set is in response to at least one restriction set.

38. The method of claim 31 herein the step of modifying at least a portion of the selected action set further comprises the steps of: receiing at least one data tpe representing a constraint on action: and implementing the constraint on at least a portion of the selected action set Ei the application of at least one restriction set.

39. The method of claim 31 herein the step of modifying at least a portion of' the selected action set is based at least in part on data received from at least one of a localization sensor, a perception sensor, and a terrain map.

40. The method of claim 31 wherein the step of modifying at least a portion of the selected action set comprises adjusting at least one of a translational elocity of the autonomous ehicle and a rotational elocity of the autonomous ehicle.

41. The method of claim 18, wherein the selective scheme comprises: defining a plurality of behaviors associated with the at least one actuator; receiving at least one mode select command; and manipulating the at least one input device in accordance itli the at least one mode command.

42. The method of claim 41 wherein the mode select command comprises a manned operation command and the step of manipulating the at least one input device comprises disassociating the at least one actuator from the at least one input device.

43. The method of claim 40 further comprising the step of reassociating the at least one actuator with the at least one input de ice.

44. The method of claim 40 further comprising the step of reassociating the at least one actuator with the at least one input device after at least one predetermined delay.

45. The method of claim 40 wherein the mode select command comprises an autonomous unmanned operation command and the step of' manipulating the at least one input de ice comprises operating the at least one input de'. ice in accordance s ith at least one of the pluralit) ot'beha'. lors.

46. The method of claim 41..herein the mode select command comprises a remote unmanned tale-operation command and the step of manipulating the at least one input device comprises operating the at least one input device in accordance with at least one remote transmission.

47. The method of claim 41 wherein the mode select command comprises a assisted remote tale-operation command and the step of manipulating the at least one input device comprises operating the at least one input de ice in accordance with (i) at least one of the plurality of behaviors. and (ii) at least one remote transmission.

48. The method of claim 47 wherein the at least one of the plurality of behaviors comprises obstacle avoidance.

49. The method of claim 18. wherein the safety scheme comprises: providing at least one control policy corresponding to the at least one input device: providing at least one controller: providing a first communication link between the at least one controller and each of the plurality of actuators: proiding a second communication link between each of the pluralit of actuators: transmitting the safety signal to at least one of the plurality of actuators via at least one of the first communication link and the second communication link: and manipulating the at least one input de ice based at least in part oil the safety signal in accordance with the at least one control policy.

50. The method of claim 49 herein the first communication link comprises at least one net ork connection.

51. The method of claim 49herein the second communication link comprises at least one current loop.

52. The method of claim 5! herein the second communication link carries a signal comprising at least one ofa manual mode signal and an autonomous mode signal. 4s 53. The method of claim 51 wherein the second communication link carries a signal comprising at least one of a stop signal and a non-stop signal.

54. The method of claim 49 wherein the step of manipulating the at least one input device corresponds to shutting down the vehicle.

55. The method of claim 49 wherein the safety signal is transmitted in response to at least one operator intervention.

56. The method of claim 49 wherein the safety signal is transmitted in response to at least one output of at least one sensor.

57. A method for tracking at least one terrain feature by an autonomous vehicle.

the method comprising the steps of: providing at least one localization sensor for determining a position of the autonomous vehicle; providing at least one perception sensor for assessing an environment about the autonomous vehicle: detecting the at least one terrain feature based at least in part on a change in at least one output of the at least one perception sensor: computing a location of the at least one terrain feature relative to the position of the autonomous ehicIe and based at least in part on at least one output of the at least one localization sensor: storing the location of the at least one terrain feature in at least one rnemoiy and updating the stored location of the at least one terrain feature based at least in part on a change in output of'at least one of the at least one localization sensor and the at least one perception sensor.

58. The method of claim 57 herein the at least one localization sensor comprises at least one of a pitch sensor. a roll sensor. a ya sensor. an inertial na igation s stem. a compass. a global positioning s stern. and an odometer.

59. The method of claim 57 wherein the at least one perception sensor comprises at least one of a LIDAR system, a stereo vision system. an infrared vision system. a radar system. and a sonar system.

60. The method of claim 57 herein the at least one perception sensor is characterized at least in part by a persistence.

61. The method of claim 57 wherein the step of storing the location of the at least one terrain feature comprises mapping the location of the at least one terrain feature froni a three dimensional representation to a two dimensional representation.

62. The method of claim 57 wherein the step of updating the stored location of the at least one terrain feature comprises recomputing the location of the at least one terrain feature based only on a change in the output of the at least one localization sensor.

63. The method of claim 57 wherein the step of updating the stored location of the at least one terrain feature comprises recomputing the location of the at least one terrain feature based only on a change in the output of the at least one perception sensor.

64. The method of claim 57 herein the step of updating the stored location of the at least one terrain feature comprises discarding the stored location based at least in part satisfying at least one predetennined condition.

65. The method of' claim 64 wherein the at least one predetermined condition comprises exceeding a predetermined displacement heteen the location of the at least one terrain feature and the position of the autonomous chicle.

66. The method of claim 60 herein the step of updating the stored location of the at least one terrain feature comprises discarding the stored location based at least in part satisf-ing at least one predetermined condition.

67. The method of claim 63 wherein the at least one predetermined condition comprises failing to achieve a predetermined persistence after the detection of the at least one terrain feature.

68. The method ot'claim 57 further comprising the step of adjusting a trajectory of the autonomous vehicle based at least in part on the location of the at least one terrain feature stored in the at least one memor.

69. The method of claim 58 wherein the step of adjusting a trajectory of the autonomous vehicle comprises selecting one preferred trajectory from a plurality of ranked alternative trajectories.

70. A system for control of a vehicle, the system comprising: means for controlling the vehicle: means for actuating the vehicle control means: and means for controlling the ehicle based at least in part on at least one of an interruptible autonomous controller. a behaior based autonomous controller, a selectie controller, and a safety controller.

71. The system of claim 70. wherein the interruptible autonomous controller comprises: means for detecting at least one disassociation beteeii the ehicle control means and the actuating means: means for interrupting autonomous control of the chicle in response to the at least one disassociation: means for detecting by the controlling means at least one restored association beteen the chicle control means and the actuating means: and means for executing a re ised chicle control program in response to the at least one restored association.

72. The system of claim 71 wherein the actuating means comprises at least one mechanical transmission.

73. The system of claim 71 wherein the disassociation comprises a separation between the ehicle control means the actuating means.

74. The system of claim 71 wherein the means for detecting at least one disassociation comprises at least one of a proximity sensor and a strain gauge.

75. The system of claim 71 wherein the reised vehicle control program comprises autonomous ehicle control.

76. The system of claim 71 wherein the revised ehic1e control program comprises at least one predetermined time delay.

77. The system of claim 71 wherein the revised vehicle control program comprises an inhibitor for preventing autononious ehic1e control.

78. The system of claim 18 wherein the revised vehicle control prograni comprises an inhibitor for pre enting autonomous ehicle control in the absence of at least one operator interention.

79. The system of claim 71 wherein the means for controlling the vehicle comprises a drie control.

80. The s stem of claim 79 herein the dri e control comprises at least one ofa throttle. brake. transmission shifier. and an accelerator.

81. The s stem of claim 71 herein the means for controlling the ehicle comprises an articulation control.

82. ilic s stem ol claim 70. wherein the interruptible autonomous controller comprises: means for detecting by the controlling means at least one disassociation between the ehicle control means and the actuating means; and means for initiating a shutdown sequence based at least in part on the disassociation between the at least one input device and the at least one actuator.

83. The sstem ofclaini 70. wherein the behavior based autonomous controller comprises: means for defining a plurality of behaviors associated with the actuating means, each behaior including at least one action set characterized at least in part by a priority.

each action set including a plurality of alternative actions ranked according to a corresponding plurality of preferences: means for selecting the action set having the highest corresponding priority; means for selecting the alternative action having the highest preference: means for implementing at least one of(i) a providing the at least one action set, and (ii) a modifying at least a portion of the selected action set; and means for operating the vehicle control means in accordance with the selected alternative action.

84. The system of claim 83 wherein the means for controlling the vehicle comprises an input de ice.

85. The system of claim 83 wherein the plurality of beha iors comprises manned operation. remote unmanned tale-operation, assisted remote taleoperation. and autonomous unmanned operation.

86. The sstem of claim 83 wherein the plurality of alternatie actions comprises at least one trajector set.

87. The system of claim 83 herein the means for modil ing at least a portion of the selected action set comprises means for determining a position of the chicle.

88. The system of claim 83 wherein the means for modifying at least a portion of the selected action set comprises means for assessing an environment about the ehicle.

89. The system of claim 83 herein the means for modifying at least a portion of the selected action set comprises means for recording at least one location of at least one terrain feature.

90. The system of claim 83 further comprising means for adjusting at least one of a translational velocity of the autonomous vehicle and a rotational velocity of the vehicle.

91. The system of claim 71, wherein the selective controller comprises: means for defining a plurality of behaviors associated vith the actuating means; means for receiing at least one mode select command; and means for manipulating the ehicle control means by the controlling means in accordance ith the at least one mode select command.

92. The system of' claim 91 vherein the mode select command comprises a manned operation command and the manipulation means comprises an inhibitor for disassociating the actuating means from the vehicle control means.

93. The system of claim 91 herein the ehicle control means comprises at least one predetermined delay.

94. The system ol'claim 91 herein the mode select command comprises an autonomous unmanned operation command and the manipulation means comprises at least one of the plurality of hehaiors.

95. The system of claim 91 herein the mode select command comprises a remote unmanned tale-operation command and the manipulation means coniprises at least one remote transmission.

96. The sstem of claim 91 herein the mode select command comprises a assisted remote tale-operation command and the manipulation means comprises at least one of the plurality of behaviors and at least one remote transmission.

97. The system of claim 96 wherein the at least one of the plurality of behaviors comprises obstacle avoidance.

98. The system of claim 70. wherein the safety controller comprises: means for processing commands for the ehic!e; means for communicating between the processing means and the actuating means: means for communicating ithiii the actuating means; means for transmitting the safety signal to the actuating means via at least one of (1) the means for communicating between the processing means, and (ii) the means for communicating ithin the actuating means: and means for manipulating the vehicle control means based at least in part on the safety signal.

99. The system of claim 98 wherein the means for communicating between the processing means and the actuating means comprises at least one network connection.

100. The system of claim 97 wherein the means for communicating within the actuating means comprises at least one current loop.

101. The sstern of claim 100 wherein the means for communicating within the actuating means carries a signal comprising at least one of a manual mode signal and an autonomous mode signal.

102. The sstem of claim 100 herein the means for communicating ithin the actuating means carries a signal comprising at least one of a stop signal and a non-stop signal.

103. The system of claim 98 wherein the safety signal is transmitted in response to at least one operator intervention.

104. The system of claim 98 wherein the safety signal is transmitted in response to at least one output of at least one sensor.

105. A system for tracking at least one terrain feature by an autonomous vehicle.

the system comprising: means for determining a position of the autonomous vehicle: means for assessing an en ironment about the autonomous vehicle: means for detecting the at least one terrain feature based at least in part on a change in the environment assessment means; means for computing a location of the at least one terrain feature relative to the position of the autonomous vehicle and based at least in part on the position determining means: means for storing the location of the at least one terrain feature: and means for updating the stored location of the at least one terrain feature based at least in part on a change in at least one of the position determining means and the environment assessment means.

106. The sy stern of claim 105 wherein the position determining means comprises at least one of a pitch sensor, a roll sensor, a ya sensor. an inertial navigation system. a compass. a global positioning system. and an odometer.

107. The s stem of claim 105 herein the at least one environment assessment means comprises at least one of a LID AR system. a stereo ision system. an infrared ision sstem. a radar sstem. and a sonar sstern.

108. l'he s stem of claim 105 herein the at least one en ironment assessment means is characterized at least in part by a persistence.

109. The system of claim 105 wherein the means for storing the location of the at least one terrain feature comprises means for mapping the location of the at least one terrain feature from a three dimensional representation to a two dimensional representation.

110. The system of claim 105 wherein the means for updatiiig the stored location of the at least one terrain feature comprises means for recomputing the location of the at least one terrain leature based only on a change in the position determining means.

111. The system of claim 105 wherein the means for updating the stored location of the at least one terrain feature comprises means for recomputing the location of the at least one terrain feature based only on a change in the environment assessment means.

112. The system of claim 105 herein the means for updating the stored location of the at least one terrain feature comprises means for discarding the stored location in response to satisling at least one predetermined condition.

113. The system of claim 112 wherein the at least one predetermined condition comprises exceeding a predetermined displacement between the location of the at least one terrain feature and the position of the autonomous vehicle.

114. The system of claim 108 wherein the means for updating the stored location of the at least one terrain feature comprises means for discarding the stored location in response to satist\ ing at least one predetermined condition.

I 15. The sstem of claim 114 herein the at least one predetermined condition comprises exceeding a predetermined persistence after the detection of the at least one terrain feature.

116. The s stem ofclaim 105 further comprising means for adjusting a trajector of the autonomous vehicle based at least in part on the locationof the at least one terrain feature stored in the at least one menior.

117. The systenl of claim 116 wherein the means for adjusting a trajectory of the autonomous vehicle comprises means for selecting one preferred trajectory from a plurality of ranked alternative trajectories.

118. A method for the control of a ehicle substantially as hereinbefore described ith reference to and as illustrated in any one of the accompanying drawings.

119. A system for control of a vehicle substantially as hereinbefore described vith reference to and as illustrated in any one of the accompanying drawings.

(J CLIEN'I 4 IO-42O(.I I')4 16324GBDI VISIONAL CLIMS LX)C