Abstract:
When a sub-section of a predefined path temporarily cannot be traversed by an autonomous mobile unit, an extended path is found for subsequently traversing the temporarily blocked sub-section. A first path point of the predefined path is determined using at least one predefinable distance criterion, which takes into consideration the distance of the temporarily blocked sub-section from the first path point. An extension sub-section is determined which begins at the first path point, terminates at a second path point of the predefined path and encompasses at least the temporarily blocked sub-section. The extended path is programmed with the extension sub-section being integrated into the predefined path at the first path point.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
     This application is based on and hereby claims priority to German Application No. 10138259.6 filed on Aug. 3, 2001, the contents of which are hereby incorporated by reference. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention relates to a method and system for programming an extended path for an autonomous mobile unit and to a computer program product and a computer-readable storage medium with a computer program stored thereon for programming an extended path for an autonomous mobile unit. 
     2. Description of Related Art 
     Repetitive activities are increasingly being reassigned to service robots. Examples of such activities include cleaning, transporting, distributing seed over relevant areas, and lawn mowing. 
     The problem with the service robots, to which associated surface-processing devices are attached, is that the surface-processing device is expected to cover as much of the available space as possible with as few paths as possible being traversed more than once. Moreover, the effort needed to program this path must be sufficiently low to require little computing capacity. This is the only way to ensure acceptable time characteristics during the programming process. 
     There is the added problem in the case of a cleaning robot whose function is to perform cleaning tasks in a supermarket, for instance, that additional obstacles in the form of customers with trolleys appear when the robot is being used while the supermarket is open for business. If the dimensions of the work area and the position of the obstacles located therein are known, it is possible with the aid of a pre-programming method to program an optimum path the traversing of which takes minimum time while simultaneously taking into consideration as much of the surface to be traversed as possible. The service robot starts traversing the path when the pre-programmed path has been pre-programmed and determined. 
     A pre-programming method of this type is known, for example, from DE 198 04 195 A1. However, any obstacles that may briefly appear, for example customers with their trolleys, consequently cannot be taken into consideration when the path is being pre-programmed. In this case the service robot detects the obstacles while moving. The robot takes evasive action, which is to say it departs from the pre-programmed path, bypasses the obstacle, and returns after the evasive action to its original path. A type of programming and execution of such evasive action is also known from DE 198 04 195 A1. However, the section of the original path that was not traversed owing to the evasive action remains unprocessed or uncleaned at this time and will have to be processed or cleaned subsequently. 
     Two different post-programming methods are known for subsequently processing unprocessed path sections of this type. In the case of the first post-programming method, the previously executed pre-programming method is executed a second time. The already traversed and accordingly processed sub-section of the original path is no longer taken into consideration here, while the unprocessed, omitted sub-section is taken into consideration during subsequent programming. 
     The disadvantage of this method, however, is that a completely new path is determined for the remaining section of the original path still to be processed on account of taking the omitted sub-section into consideration. Yet this complete re-programming results in unnecessarily long programming times and places a high demand on computing power. A provision in this case of the second known post-programming method is for the unprocessed path section to be appended at the end of the original path and to be traversed on completion of the path. However, this method results in unnecessarily extended paths and so is also inefficient. 
     Other path programming methods are known from “Approximation Algorithms for Lawn Mowing and Milling”, Arkin E. M. et al., Angewandte Mathematik und Informatik (Applied Mathematics and Computer Science), University of Cologne, Report No. 97.255, 1997. 
     SUMMARY OF THE INVENTION 
     An object of the invention is accordingly to disclose a path programming method for an autonomous mobile unit facilitating efficient and flexible programming of a path extended to include an alternative path. 
     This object may be achieved by a method for programming an extended path for an autonomous mobile unit to determine a sub-section of a predefined path which cannot be traversed by the autonomous mobile unit. A non-traversable sub-section of this kind may occur if an obstacle blocks the predefined path. Such blocking is generally only temporary so that the sub-section is at times non-traversable. 
     The method further entails determining a first path point of the predefined path using at least one predefinable distance criterion which takes into consideration a distance from the sub-section to the first path point. An extension sub-section is thereupon determined which begins at the first path point, terminates at a second path point of the predefined path, and encompasses at least the sub-section. When the extended path is programmed, the extension sub-section is integrated into the predefined path at the first path point. 
     The system for programming an extended path for an autonomous mobile unit has a path programming unit, for example a computer processor, which is set up to perform the following steps. A section of a pre-determined path can be determined which is a sub-section of the path and which cannot be traversed by the autonomous mobile unit. A first path point of the predefined path can furthermore afterwards be determined using at least one predefinable distance criterion which takes into consideration a distance from the sub-section to the first path point. An extension sub-section can thereupon be determined which begins at the first path point, terminates at a second path point of the predefined path, and encompasses at least the sub-section. When the extended path is programmed, the extension sub-section can be integrated into the predefined path at the first path point. 
     The computer program product, which includes a computer-readable storage medium on which a program is stored, allows a computer, after the program has been loaded into a memory of the computer, to execute the following steps for programming an extended path for an autonomous mobile unit. A section of a pre-determined path can be determined which is a sub-section of the path and which cannot be traversed by the autonomous mobile unit. A first path point of the predefined path can furthermore afterwards be determined using at least one predefinable distance criterion which takes into consideration a distance from the sub-section to the first path point. 
     An extension sub-section can thereupon be determined which begins at the first path point, terminates at a second path point of the predefined path, and encompasses at least the sub-section. When the extended path is programmed, the extension sub-section can be integrated into the predefined path at the first path point. 
     On the computer-readable storage medium a program is stored which allows the computer, after the program has been loaded into a storage medium of the computer, to execute the following steps for programming an extended path for an autonomous mobile unit. A section of a pre-determined path can be determined which is a sub-section of the path and which cannot be traversed by the autonomous mobile unit. A first path point of the predefined path can furthermore afterwards be determined using at least one predefinable distance criterion which takes into consideration a distance from the sub-section to the first path point. 
     An extension sub-section can thereupon be determined which begins at the first path point, terminates at a second path point of the predefined path, and encompasses at least the sub-section. When the extended path is programmed, the extension sub-section can be integrated into the predefined path at the first path point. 
     The system, the computer program product, and the computer-readable storage medium are particularly suitable for carrying out the method according to the invention or one of its developments explained in the following. 
     A particular advantage of the invention is that when the extended path is being programmed the predefined, original path is used as a basis for programming additional subsections of the extension path which only extend or supplement the predefined path. This obviates the need for re-programming which would result in a routing that may be substantially different from the original path. This saves computing power and memory space. The programming process is also accelerated. 
     The invention has the further advantage that no additional information is needed when the extended path is programmed, such as information requiring to be newly integrated about the surroundings. Only information already contained in the predefined path is used when the extended path is programmed. This is very advantageous especially when the predefined path contains manually integrated knowledge which cannot be generated automatically, or can be generated only with great difficulty. 
     The developments described in the following relate both to the method and to the system. The invention and developments described in the following can be implemented both as software and as hardware, for example using special electric circuitry. The invention or a development described in the following can furthermore be implemented by a computer-readable storage medium on which is stored a computer program which executes the invention or development. 
     The invention or any of the developments described in the following can also be implemented by a computer program product having a storage medium on which is stored a computer program which executes the invention or development. 
     Other criteria can be used besides the distance criterion when the first path point is being determined, for example a cinematic criterion taking into consideration a cinematic characteristic of the autonomous mobile unit. 
     A further criterion or further criteria can be a time criterion and/or a processing criterion taking into consideration a travel time and/or travel route of the autonomous mobile unit. 
     The first path point can furthermore also be determined by applying standard methods of graph theory according to Dijkstra which are known from “Introduction to Algorithms”, Thomas H. Cormen et al., The MIT Press, Cambridge, Mass., 23rd edition, London, 1999, McGraw-Hill Book Company, New York. 
     The extension sub-section includes, in one embodiment, at least one further sub-section of the predefined path in addition to the sub-section which cannot be traversed by the autonomous mobile unit. It is also possible for the extension sub-section largely to comprise sub-sections of the predefined path. 
     In one development, the second path point is identical to the first path point. This, in plain terms, means the autonomous mobile unit departs from the originally programmed path at one path point, traverses the sub-section which could not be traversed at an earlier time, then returns at the same path point to the originally programmed path. 
     In certain circumstances, for example when the path routing is complex, it may be favorable in terms of achieving as short and effective path routing as possible, for the second path point to be situated on the predefined path after the first path point. This makes it possible to avoid repeated traversing of the same path section. 
     The method for programming an extended path for an autonomous mobile unit is preferably employed in a recursive path programming method in such a way that the extended path, which was determined in a preceding iteration step, is the predefined path of an iteration step following the preceding iteration step. This makes it possible to promptly take into consideration any suddenly appearing new obstacles by an extension program without the need to determine a completely new path whenever new obstacles appear. The method or a development thereof is employed in one embodiment in a cleaning robot which, in this case, traverses the extended path in the course of a cleaning activity and cleans at least sections of the extended path. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       These and other objects and advantages of the present invention will become more apparent and more readily appreciated from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings of which: 
         FIG. 1  is a map of a space to be cleaned by a cleaning robot with a pre-programmed cleaning path; 
         FIG. 2  is a schematic perspective view of a cleaning robot with a cleaning device and recording means; 
         FIG. 3  is a map of a space to be cleaned by a cleaning robot with a pre-programmed cleaning path and an obstacle blocking a section of a pre-programmed path, and an extended subsequent cleaning path; 
         FIG. 4  is a map of a space to be cleaned by a cleaning robot with a pre-programmed cleaning path, a first obstacle blocking a first section of the pre-programmed path, an associated first extended subsequent cleaning path and a second obstacle blocking a second section of the pre-programmed path, and an associated second alternative extended subsequent cleaning path; 
         FIG. 5  is a flowchart showing method-related steps of an exemplary embodiment; 
         FIGS. 6   a  to  6   f  are maps of a space to be cleaned by a cleaning robot with cleaning paths and obstacles according to a recorded log file. 
     
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     Reference will now be made in detail to the preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings, wherein like reference numerals refer to like elements throughout. 
       FIG. 2  shows a cleaning robot  201  with a cleaning device  210  and a plurality of laser scanners  202 . The laser scanners  202  record images of the surroundings of the cleaning robot  201  and route the images to a computing unit  203  via connections  204 ,  205 . The image signals are routed to the memory  208  via an input/output interface  206  connected via a bus  207  to a memory  208  and a processor  209 . 
     The method described in the following is executed in the processor  209 . The processor  209  is therefore set up such that the method-related steps described in the following are executable. 
       FIG. 1  is a symbolic depiction of the map  101  produced by the cleaning robot  201  representing a space to be cleaned by the cleaning robot  201 . In plain terms, a map  101  of this type is an electronic image of the space to be cleaned. 
     The map  101  is produced by the cleaning robot  201  in such a way that the robot moves through the space and, by the laser scanners  202 , records images of its surroundings at different instances and at different locations in the space to be cleaned. The recorded images of the space are stored by the cleaning robot  201  and brought together into the map  101  which is also stored. Walls  103  within the space as well as obstacles  104  in the form of shelving or cabinets protruding into the space are therefore imaged in the map  101 . 
     With the aid of the map  101 , as part of a pre-programming action using a pre-programming method the cleaning robot  201  determines an optimal, pre-programmed cleaning path  110  the traversing of which will take a minimum length of time but take into consideration as much as possible of the area comprising the space to be traversed and cleaned. The pre-programmed cleaning path  110  is entered in the map  101  and stored. 
       FIG. 1  shows the pre-programmed path  110 . The pre-programmed path  110  starts at point S (start)  111  and leads from there along an indicated path line  112  in the direction of the arrow  113  to point E (end)  114 . The pre-programming method executed by the cleaning robot  201  is described in DE 198 04 195 A1. 
     When pre-programming has been completed and the pre-programmed path  110  has been determined, as part of a cleaning process the service robot begins to traverse the path  110 . During the cleaning process the cleaning device  210  of the cleaning robot  201  is in active contact with the floor of the space to be cleaned. 
     The cleaning robot  201  moves along the pre-programmed and stored path  110  or indicated path line  112  and records images of its surroundings at periodic intervals. The robot  201  orientates itself in the space by comparing the recorded images with the stored map. 
     The cleaning robot  201  continues traversing the pre-programmed path  110  until it detects a new obstacle which was not taken into consideration during pre-programming and which is blocking a section of the pre-programmed path  110 . An obstacle of this type can be, for instance, a person situated within the space or another mobile item of furniture. 
     Blocking of the pre-programmed path  110  by the new obstacle prevents a sub-section of the original path  110  from being traversed and requires an alternative path or subsequent cleaning path to be programmed. A subsequent cleaning path of this type includes not only an altered path course in the narrower sense, which is to say not only a path for bypassing the new obstacle and not only an additional subsequent cleaning sub-section integrated at a subsequent point along the pre-programmed path, but the entire, newly programmed path course which also includes path sections remaining unaltered with respect to the pre-programmed path. A programming and execution of a path sub-section for bypassing or circumnavigating an obstacle is described in DE 198 04 195 A1. 
     The programming of a subsequent cleaning path of this type is described in the following.  FIG. 3  shows the stored map  101  with the pre-programmed path  110  and a new obstacle  301 , and a subsequent cleaning path programmed by the cleaning robot with the path sub-sections  302 ,  303 ,  304 ,  305 ,  306 , and  307 . 
     The following fundamental programming strategies are applied to the programming of a subsequent cleaning path:
     a) No subsequent cleaning path will be programmed if an object is blocking a section which is a sub-section of the pre-programmed path and which will be traversed again at a subsequent point along the pre-programmed path. The obstacle will be circumnavigated as closely as possible taking a predefined safety clearance into consideration.   b) If an object is blocking a section which is a sub-section of the pre-programmed path and which will not be traversed again at a subsequent point along the pre-programmed path, a subsequent cleaning path will be programmed in the manner described below:   b0) The subsequent cleaning path will include the path sub-section on which the cleaning robot will circumnavigate the new obstacle as closely as possible while maintaining a predefined safety clearance.   b1) That particular path point in the pre-programmed path will be determined which is situated closest to the pre-programmed path sub-section which is blocked and which will be omitted when the new obstacle is circumnavigated, or to the obstacle. An additional path section will be integrated into the pre-programmed path at this nearest path point.   b2) The sub-section being additionally integrated leads from the nearest path point to that particular path point in the pre-programmed path at which the cleaning robot will depart from the pre-programmed path when circumnavigating the new obstacle or will rejoin the path after circumnavigating the new obstacle (approach sub-section).   b3) The sub-section being additionally integrated furthermore includes the sub-section which will be omitted when the new obstacle is circumnavigated and which will be appended to the approach sub-section.   b4) A return sub-section leading back to the nearest path point will be added to the appended sub-section.   b5) The further course of the subsequent cleaning path will correspond to the original course of the pre-programmed path.   c) The subsequent cleaning path will replace the pre-programmed path during the further course of the cleaning process.   d) If the cleaning robot encounters another new obstacle during the further course of the cleaning process, which is to say while traversing the subsequent cleaning path replacing the original, pre-programmed path, the above described programming strategies will be recursively re-executed analogously.   

     According to the above fundamental programming strategies, the cleaning path  302  to  307  described in the following will be determined by the cleaning robot  201 . Corresponding method-related steps are shown in  FIG. 5 . When the cleaning robot  201  reaches path point A, at which it detects the new obstacle  301 , it will trigger programming of the subsequent cleaning path  302  to  307  ( 500 ). The subsequent cleaning path  302  to  307  leads from the path point A past the new obstacle  301   302 , maintaining a predefined safety clearance with respect to the new obstacle  301  ( 505 ). The subsequent cleaning path  302  to  307  rejoins the original, pre-programmed path  110  at point B. The cleaning robot stores the fact that the path section  305  which is a section of the pre-programmed path  110  and which is delimited by the points A and B was not traversed or cleaned and so was omitted ( 505 ). The cleaning robot  201  then checks whether the non-traversed or omitted path section  305  will be traversed again at a subsequent point in the pre-programmed cleaning path  110  ( 510 ). 
     This does not apply to the pre-programmed cleaning path  110 , so that subsequent cleaning of the omitted sub-section  305  and corresponding programming of the subsequent cleaning path  302  to  307  is necessary. Further programming of the subsequent cleaning path  302  to  307  would otherwise be unnecessary ( 511 ). The original, pre-programmed path course  112  would continue to apply. 
     The cleaning robot  201  checks the subsequent path points along the further course of the pre-programmed path  110  to ascertain which path point is situated closest to the omitted path section  305  ( 515 ). To do so, it determines the path point C at which path sub-sections  304  to  306  of the subsequent cleaning path  302  to  307  are integrated ( 515 ). 
     The subsequent cleaning path  302  to  307  thereafter proceeds from point B along the original path  110  to point C  303 . From point C the subsequent cleaning path proceeds by the shortest link to point B  304 , which is the last path point of the omitted sub-section  305  ( 520 ). 
     From point B the subsequent cleaning path  302  to  307  proceeds along the original path  110  to point A  305 , with the omitted sub-section  305  being traversed counter to the originally programmed direction of travel and cleaned in he process ( 525 ). 
     From point A the subsequent cleaning path  302  to  307  proceeds to return by the shortest link  306  to point C and so rejoins the original pre-programmed path  110  ( 530 ). The subsequent course  307  of the subsequent cleaning path  302  to  307  corresponds to the original course of the pre-programmed path  110  and ends at point E ( 535 ). 
     Alternatives Ai (i=number of the respective alternative) to the exemplary embodiment are described in the following. 
     In one alternative (A1) to the exemplary embodiment the map  101  is not generated by traversing and recording the space to be cleaned but, instead, was produced in advance by means, for example, of a programming action, and is stored in the cleaning robot. 
     In a further alternative (A2) to the exemplary embodiment a cinematic criterion taking into consideration a cinematic characteristic of the autonomous mobile unit is employed in addition to the distance criterion when the nearest point C, the integration point of the extension sub-section, is being determined. 
     If, for example, a cleaning robot  201  has a tricycle cinematic characteristic, which is to say it only moves on three wheels, certain points within the space will only be approachable with considerable difficulty and only with the cleaning robot&#39;s having attained a specific orientation. A complex shunting maneuver would have to be executed by the robot in such cases in order to attain a predefined orientation. 
     With this alternative the nearest point C is displaced along the pre-programmed path until it can also be approached cinematically favorably by the cleaning robot, which is to say without the need for major shunting maneuvers. Subsequent programming steps will be executed in accordance with the original method. 
     In a further alternative (A3) to the exemplary embodiment a time criterion and a processing criterion taking into consideration a travel time and a travel route of the cleaning robot are employed in addition to the distance criterion when the nearest point C, the integration point of the extension sub-section, is being determined. 
     With this alternative the nearest point C is displaced along the pre-programmed path until it can also be approached favorably in conditions relating to time and processing. Subsequent programming steps will be executed in accordance with the original method. 
     Conditions favorable in terms of time are to be understood as cleaning which is of as short a duration as possible. Conditions favorable in terms of processing are to be understood as cleaning positions which are as efficient as possible. 
     A fourth alternative (A4) to the exemplary embodiment relates to determining the return sub-section  306  (strategy step b4). It may be more favorable in terms of, for example, cleaning efficiency, for the return sub-section to end at a path point along the pre-programmed path which is different from the start point, which is to say at the nearest point C (see also exemplary embodiment). A case such as this is shown in  FIG. 4 . 
       FIG. 4  shows the stored map  101  with the configuration according to the exemplary embodiment, which is to say with the pre-programmed path  110 , and with the new obstacle  301 , and also the subsequent cleaning path which was programmed by the cleaning robot and which has the path sub-sections  302 ,  303 ,  304 ,  305 ,  307 , and  307 . 
       FIG. 4  also shows another new obstacle  401  and the associated subsequent cleaning path which was programmed by the cleaning robot and which has the path sub-sections  402 ,  403 ,  404 ,  405 ,  406 , and  407 . In this case the return sub-section  406  does not end at point C but at a point D. The path sub-section  408  of the original path  110  between the points C and D remains uncleaned in this case. 
     It should be noted that the original programming method can also be modified by any combinations of the described alternatives. 
     Shown below is a commented log file recorded by the cleaning robot during a cleaning process. A log file of this type is generally produced during a cleaning process (online). The cleaning robot records all programming and travel processes, which are stored in the log file. This allows the programming and travel processes to be retraced and checked on completion of the cleaning process. The log file shown below records various path courses traversed by the cleaning robot ( FIG. 6   a  to  FIG. 6   f ) and contains comments on which path courses were determined according to the programming methods described in the preceding. 
     
       
         
               
             
               
             
               
               
               
             
               
             
               
               
             
               
               
               
             
               
               
             
               
               
               
             
               
               
             
               
               
               
             
               
               
             
               
               
               
             
               
               
             
               
               
               
             
               
               
               
             
               
               
             
               
               
               
             
               
               
             
               
               
               
             
               
               
             
               
               
               
             
               
               
             
               
             
               
               
             
               
             
               
               
               
             
               
             
               
               
             
               
             
               
               
             
               
             
           
               
                   
               
               
                 Log file: 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                 The robot cleans until encountering an obstacle at configuration 129. (FIG. 6a, image 
               
               
                 1_129) 
               
               
                 No subsequent cleaning is programmed because the robot will in any event be passing 
               
               
                 through that location again. (FIG. 6b, image 2_219) 
               
               
                 However, since the obstacle was still there, the robot again has to take evasive action. 
               
               
                 Subsequent cleaning is then programmed: 
               
             
          
           
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 [467] 265 200 201 202 203 204 205 206 207 208 209 210 
               
               
                   
                   
                 211 212 213 214 215 216 21 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 [487] 219 220 221 222 223 224 225 226 227 228 229 230 
               
               
                   
                   
                 231 232 233 234 235 236 23 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 [507] 239 240 241 242 243 244 245 246 247 248 249 250 
               
               
                   
                   
                 251 252 253 254 255 256 25 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 [527] 259 260 261 262 263 264 265 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 ********* Detour ready ********* 
               
               
                 1 
                 16:26:35.838&gt; Recur 
                 detour 265 (6.7 m) [213...223) (14.8 m) 265 (for 564 cells) 
               
               
                   
                   
                 waiting 
               
             
          
           
               
                 This means that additional configurations 467 to 533 are generated which are integrated 
               
               
                 into the standard path after 265. 
               
               
                 The robot is on its way to rounding the lower island, but it then turns off in an upward 
               
               
                 direction after configuration 265. (FIG. 6c, image 3_472) 
               
               
                 The omitted location will be cleaned subsequently (FIG. 6d, image 4_488) . In order to 
               
               
                 continue with the side of the aisle next to the island it must then proceed right to the 
               
               
                 bottom again, but it then resumes its journey at the interrupted location (FIG. 6e, image 
               
               
                 5_528; FIG. 6f, image 6_267). The path is then ended with no interruptions. 
               
               
                 Extract from the log file: 
               
               
                 -------------------------&gt; ------------------------------------------------------------- 
               
               
                 ------------ 
               
               
                 1 16:01:10.175&gt; Mission 923 started (23.05.2001), Version 2.01.02 
               
               
                 -------------------------&gt; ------------------------------------------------------------- 
               
               
                 ------------ 
               
             
          
           
               
                 1 
                 16:01:10.175&gt; Mission - start execution of path ‘PATH9’ 
               
               
                 . . .  
               
             
          
           
               
                 Debug 
                 16:01:22.933&gt; Recur 
                 Precalc 0: Next look after 171 
               
               
                 Debug 
                 16:01:24.205&gt; Recur 
                 Precalc 1: Next look after 172 
               
             
          
           
               
                 2 
                 16:02:32.523&gt; Recur starts new search for detour 
               
             
          
           
               
                 Debug 
                 16:02:32.693&gt; Recur 
                 5-&gt;6 uncleaned: 77 cells now, 5 cells at end 
               
               
                 Debug 
                 16:02:32.854&gt; Recur 
                 6-&gt;7 uncleaned: 35 cells now, 6 cells at end 
               
               
                 Debug 
                 16:02:33.014&gt; Recur 
                 7-&gt;8 uncleaned: 14 cells now, 7 cells at end 
               
               
                 Debug 
                 16:02:33.174&gt; Recur 
                 23-&gt;24 staying uncleaned: 7 cells now, 7 cells at end 
               
               
                 Debug 
                 16:02:33.354&gt; Recur 
                 24-&gt;25 staying uncleaned: 16 cells now, 16 cells at end 
               
               
                 Debug 
                 16:02:33.575&gt; Recur 
                 25-&gt;26 staying uncleaned: 14 cells now, 14 cells at end 
               
               
                 Debug 
                 16:02:33.735&gt; Recur 
                 26-&gt;27 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:02:33.905&gt; Recur 
                 33-&gt;34 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:02:34.065&gt; Recur 
                 34-&gt;35 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:02:34.226&gt; Recur 
                 35-&gt;36 staying uncleaned: 6 cells now, 6 cells at end 
               
               
                 Debug 
                 16:02:34.556&gt; Recur 
                 45-&gt;46 uncleaned: 51 cells now, 17 cells at end 
               
               
                 Debug 
                 16:02:34.716&gt; Recur 
                 46-&gt;47 uncleaned: 114 cells now, 37 cells at end 
               
               
                 Debug 
                 16:02:34.876&gt; Recur 
                 47-&gt;48 uncleaned: 226 cells now, 44 cells at end 
               
               
                 Debug 
                 16:02:34.876&gt; Recur 
                 Best cleaning path: 45–48 (98 cells) 
               
               
                 Debug 
                 16:02:34.876&gt; Recur 
                 No dirt spot big enough for detour 
               
               
                 . . .  
               
             
          
           
               
                 2 
                 16:15:32.555&gt; Recur starts new search for detour 
               
             
          
           
               
                 Debug 
                 16:15:36.761&gt; Recur 
                 Best cleaning path: 23–27 (41 cells) 
               
               
                 Debug 
                 16:15:36.761&gt; Recur 
                 No dirt spot big enough for detour 
               
             
          
           
               
                 2 
                 16:25:29.884&gt; Recur starts new search for detour 
               
             
          
           
               
                 Debug 
                 16:25:32.097&gt; Recur 
                 Best cleaning path: 213–217 (259 cells) 
               
               
                 Debug 
                 16:25:32.097&gt; Recur 
                 Dirt spot likely to be bigger than can be checked now 
               
               
                 . . .  
               
             
          
           
               
                 2 
                 16:26:33.004&gt; Recur starts new search for detour 
               
             
          
           
               
                 Debug 
                 16:26:33.074&gt; Recur 
                 5-&gt;6 staying uncleaned: 7 cells now, 7 cells at end 
               
               
                 Debug 
                 16:26:33.135&gt; Recur 
                 6-&gt;7 staying uncleaned: 6 cells now, 6 cells at end 
               
               
                 Debug 
                 16:26:33.205&gt; Recur 
                 7-&gt;8 staying uncleaned: 7 cells now, 7 cells at end 
               
               
                 Debug 
                 16:26:33.275&gt; Recur 
                 23-&gt;24 staying uncleaned: 7 cells now, 7 cells at end 
               
               
                 Debug 
                 16:26:33.345&gt; Recur 
                 24-&gt;25 staying uncleaned: 16 cells now, 16 cells at end 
               
               
                 Debug 
                 16:26:33.415&gt; Recur 
                 25-&gt;26 staying uncleaned: 14 cells now, 14 cells at end 
               
               
                 Debug 
                 16:26:33.485&gt; Recur 
                 26-&gt;27 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:26:33.555&gt; Recur 
                 33-&gt;34 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:33.615&gt; Recur 
                 34-&gt;35 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:26:33.685&gt; Recur 
                 35-&gt;36 staying uncleaned: 6 cells now, 6 cells at end 
               
               
                 Debug 
                 16:26:33.755&gt; Recur 
                 55-&gt;56 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:33.826&gt; Recur 
                 56-&gt;57 staying uncleaned: 7 cells now, 7 cells at end 
               
               
                 Debug 
                 16:26:33.906&gt; Recur 
                 57-&gt;58 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:33.966&gt; Recur 
                 67-&gt;68 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:26:34.036&gt; Recur 
                 79-&gt;80 uncleaned: 7 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:34.106&gt; Recur 
                 80-&gt;81 staying uncleaned: 12 cells now, 12 cells at end 
               
               
                 Debug 
                 16:26:34.176&gt; Recur 
                 81-&gt;82 staying uncleaned: 6 cells now, 6 cells at end 
               
               
                 Debug 
                 16:26:34.256&gt; Recur 
                 82-&gt;83 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:34.356&gt; Recur 
                 136-&gt;137 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:34.426&gt; Recur 
                 13,7-&gt;138 staying uncleaned: 9 cells now, 9 cells at end 
               
               
                 Debug 
                 16:26:34.527&gt; Recur 
                 146-&gt;147 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:26:34.627&gt; Recur 
                 152-&gt;153 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:26:34.697&gt; Recur 
                 213-&gt;214 staying uncleaned: 17 cells now, 17 cells at 
               
               
                   
                   
                 end 
               
               
                 Debug 
                 16:26:34.807&gt; Recur 
                 214-&gt;215 uncleaned: 54 cells now, 50 cells at end 
               
               
                 Debug 
                 16:26:34.907&gt; Recur 
                 215-&gt;216 uncleaned: 115 cells now, 93 cells at end 
               
               
                 Debug 
                 16:26:34.977&gt; Recur 
                 216-&gt;217 uncleaned: 255 cells now, 126 cells et end 
               
               
                 Debug 
                 16:26:35.127&gt; Recur 
                 217-&gt;218 uncleaned: 123 cells now, 43 cells at end 
               
               
                 Debug 
                 16:26:35.198&gt; Recur 
                 218-&gt;219 uncleaned: 91 cells now, 51 cells at end 
               
               
                 Debug 
                 16:26:35.268&gt; Recur 
                 219-&gt;220 uncleaned: 76 cells now, 61 cells at end 
               
               
                 Debug 
                 16:26:35.338&gt; Recur 
                 220-&gt;221 uncleaned: 69 cells now, 65 cells at end 
               
               
                 Debug 
                 16:26:35.408&gt; Recur 
                 221-&gt;222 staying uncleaned: 44 cells now, 44 cells at 
               
               
                   
                   
                 end 
               
               
                 Debug 
                 16:26:35.478&gt; Recur 
                 222-&gt;223 uncleaned: 17 cells now, 14 cells at end 
               
               
                 Debug 
                 16:26:35.688&gt; Recur 
                 239-&gt;240 staying uncleaned: 11 cells now, 11 cells at 
               
               
                   
                   
                 end 
               
               
                 Debug 
                 16:26:35.758&gt; Recur 
                 240-&gt;241 uncleaned: 18 cells now, 12 cells at end 
               
               
                 Debug 
                 16:26:35.828&gt; Recur 
                 241-&gt;242 uncleaned: 17 cells now, 7 cells at end 
               
               
                 Debug 
                 16:26:35.828&gt; Recur 
                 Best cleaning path: 213–223 (564 cells) 
               
               
                 Debug 
                 16:26:35.828&gt; Recur 
                 Result FindOmittedAreas: 213–223 (564 cells) 
               
               
                 Debug 
                 16:26:35.828&gt; Recur 
                 Find detour after: 247 
               
               
                 Debug 
                 16:26:35.828&gt; Recur 
                 Best branch: 265(=265) 6.75 m 
               
               
                 Debug 
                 16:26:35.828&gt; Recur 
                 Good branch: 265(=265) 6.75 m 
               
               
                 Debug 
                 16:26:35.828&gt; Recur 
                 Last branch: 466(=466) 17.49 m 
               
               
                 Debug 
                 16:26:35.828&gt; Recur 
                 Found detour, insert between 265 and 265 
               
               
                 Debug 
                 16:26:35.828&gt; Recur 
                 Start planning detour 
               
               
                 Debug 
                 16:26:35.838&gt; CleanOpt 
                 Plan: 265 200 201 202 203 204 205 206 207 208 209 210 
               
               
                   
                   
                 211 212 213 
               
               
                 Debug 
                 16:26:35.838&gt; CleanOpt 
                 Plan: 223 224 225 226 227 228 229 230 231 232 233 234 
               
               
                   
                   
                 235 236 237 238 239 240 2 
               
               
                 Debug 
                 16:26:35.838&gt; CleanOpt 
                 243 244 245 246 247 248 249 250 251 252 253 254 255 256 
               
               
                   
                   
                 257 258 259 260 261 262 
               
               
                 Debug 
                 16:26:35.838&gt; CleanOpt 
                 263 264 265 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 Generated Detour: 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 [467] 265 200 201 202 203 204 205 206 207 208 209 210 
               
               
                   
                   
                 211 212 213 214 215 216 21 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 [487] 219 220 221 222 223 224 225 226 227 228 229 230 
               
               
                   
                   
                 231 232 233 234 235 236 23 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 [507] 239 240 241 242 243 244 245 246 247 248 249 250 
               
               
                   
                   
                 251 252 253 254 255 256 25 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 [527] 259 260 261 262 263 264 265 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 ********* Detour ready ********* 
               
               
                 1 
                 16:26:35.838&gt; Recur 
                 detour 265 (6.7 m) [213...223] (14.8 m) 265 (for 564 cells) 
               
               
                   
                   
                 waiting 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 Time:2 sec Lat: 0 
               
               
                 Debug 
                 16:26:35.838&gt; Recur 
                 Will continue searching 
               
               
                 Debug 
                 16:26:35.919&gt; Recur 
                 Add detour from 265 to 467. .532:265 
               
             
          
           
               
                 1 
                 16:26:35.919&gt; ######## Detour: 
                 cleaning program changed! 
               
             
          
           
               
                 2 
                 16:26:35.929&gt; Recur starts new search for detour 
               
             
          
           
               
                 Debug 
                 16:26:36.019&gt; Recur 
                 5-&gt;6 staying uncleaned: 7 cells now, 7 cells at end 
               
               
                 Debug 
                 16:26:36.119&gt; Recur 
                 6-&gt;7 staying uncleaned: 6 cells now, 6 cells at end 
               
               
                 Debug 
                 16:26:36.209&gt; Recur 
                 7-&gt;8 staying uncleaned: 7 cells now, 7 cells at end 
               
               
                 Debug 
                 16:26:36.299&gt; Recur 
                 23-&gt;24 staying uncleaned: 7 cells now, 7 cells at end 
               
               
                 Debug 
                 16:26:36.419&gt; Recur 
                 24-&gt;25 staying uncleaned: 16 cells now, 16 cells at end 
               
               
                 Debug 
                 16:26:36.519&gt; Recur 
                 25-&gt;26 staying uncleaned: 14 cells now, 14 cells at end 
               
               
                 Debug 
                 16:26:36.610&gt; Recur 
                 26-&gt;27 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:26:36.700&gt; Recur 
                 33-&gt;34 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:36.790&gt; Recur 
                 34-&gt;35 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:26:36.900&gt; Recur 
                 35-&gt;36 staying uncleaned: 6 cells now, 6 cells at end 
               
               
                 Debug 
                 16:26:36.990&gt; Recur 
                 55-&gt;56 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:37.110&gt; Recur 
                 56-&gt;57 staying uncleaned: 7 cells now, 7 cells at end 
               
               
                 Debug 
                 16:26:37.230&gt; Recur 
                 57-&gt;58 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:37.351&gt; Recur 
                 67-&gt;68 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:26:37.461&gt; Recur 
                 79-&gt;80 uncleaned: 7 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:37.581&gt; Recur 
                 80-&gt;81 staying uncleaned: 12 cells now, 12 cells at end 
               
               
                 Debug 
                 16:26:37.671&gt; Recur 
                 81-&gt;82 staying uncleaned: 6 cells now, 6 cells at end 
               
               
                 Debug 
                 16:26:37.761&gt; Recur 
                 82-&gt;83 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:37.851&gt; Recur 
                 136-&gt;137 staying uncleaned: 5 cells now, 5 cells at end 
               
               
                 Debug 
                 16:26:37.941&gt; Recur 
                 137-&gt;138 staying uncleaned: 9 cells now, 9 cells at end 
               
               
                 Debug 
                 16:26:38.032&gt; Recur 
                 146-&gt;147 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:26:38.122&gt; Recur 
                 152-&gt;153 staying uncleaned: 4 cells now, 4 cells at end 
               
               
                 Debug 
                 16:26:38.492&gt; Recur 
                 Best cleaning path: 23–27 (41 cells) 
               
               
                 Debug 
                 16:26:38.492&gt; Recur 
                 No dirt spot big enough for detour 
               
               
                 . . .  
               
             
          
           
               
                 2 
                 16:27:39.290&gt; Recur starts new search for detour 
               
             
          
           
               
                 Debug 
                 16:27:42.404&gt; Recur 
                 Best cleaning path: 23–27 (41 cells) 
               
               
                 Debug 
                 16:27:42.404&gt; Recur 
                 No dirt spot big enough for detour 
               
               
                 . . .  
               
             
          
           
               
                 2 
                 16:38:34.131&gt; Recur starts new search for detour 
               
             
          
           
               
                 Debug 
                 16:38:34.151&gt; Recur 
                 Best cleaning path: 23–27 (41 cells) 
               
               
                 Debug 
                 16:38:34.151&gt; Recur 
                 No dirt spot big enough for detour 
               
               
                 . . .  
               
             
          
           
               
                 1 
                 16:38:41.332&gt; Mission - execution of path ‘PATHS’ successfully finished 
               
             
          
           
               
                 -------------------------&gt; ------------------------------------------------------------- 
               
               
                 ------------ 
               
             
          
           
               
                 2 
                 16:38:42.193&gt; Global Grid Statistics 
               
               
                 2 
                 16:38:42.193&gt; Path ‘PATHS’, started 23.05.2001 16:01:08, duration 37:34 minutes 
               
             
          
           
               
                 -------------------------&gt; ------------------------------------------------------------- 
               
               
                 ------------ 
               
             
          
           
               
                 2 
                 16:38:42.193&gt; 
                 To be cleaned: 63.12 square meters, 100.00%, 18134 cells 
               
               
                 2 
                 16:38:42.193&gt; 
                 Already wet: 0.00 square meters, 0.00%, 0 cells 
               
               
                 2 
                 16:38:42.193&gt; 
                 Cleaned: 62.26 square meters, 98.63%, 17886 cells 
               
               
                 2 
                 16:38:42.193&gt; 
                 Still wet: 0.00 square meters, 0.00%, 0 cells 
               
               
                 2 
                 16:38:42.193&gt; 
                 Still dirty: 0.86 square meters, 1.37%, 248 cells 
               
             
          
           
               
                 -------------------------&gt; ------------------------------------------------------------- 
               
               
                 ------------ 
               
               
                 -------------------------&gt; ------------------------------------------------------------- 
               
               
                 ------------ 
               
             
          
           
               
                 2 
                 16:38:42.193&gt; Recur Statistics 
               
             
          
           
               
                 -------------------------&gt; ------------------------------------------------------------- 
               
               
                 ------------ 
               
             
          
           
               
                 2 
                 16:38:42.193&gt; No|sec lat|    path      |spot dirty cleaned 
               
               
                 2 
                 16:38:42.193&gt; --+-------+----------------------+--------------------------------- 
               
               
                 2 
                 16:38:42.193&gt; 11 2 01 265&lt; 6.7 m&gt; 213–223&lt; 14.8 m&gt; 2651 564 41 523 
               
               
                 2 
                 16:38:42.193&gt; --+-------+----------------------+--------------------------------- 
               
               
                 2 
                 16:38:42.193&gt; Extra way: 21.5 meters. Extra time: 3:53 minutes. 
               
               
                 2 
                 16:38:42.193&gt; Cleaned 523 cells = 1.8 square meters altogether. 
               
               
                 2 
                 16:38:42.193&gt; 93% of targeted dirt reached. 
               
             
          
           
               
                 -------------------------&gt; ------------------------------------------------------------- 
               
               
                   
               
             
          
         
       
     
     The invention has been described in detail with particular reference to preferred embodiments thereof and examples, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention.