the following detailed description presents a description of certain specific embodiments of the present invention . however , the present invention may be embodied in a multitude of different ways as defined and covered by the claims . in this description , reference is made to the drawings wherein like parts are designated with like numerals throughout . aspects of the present invention are directed towards a system and robotic or remote control method for mopping a floor . in particular , the system overcomes the drawbacks of having a mopping device carry reservoirs of clean and dirty water as well as a detergent or other cleaning or waxing solutions . fig1 shows a front perspective of one embodiment of an autonomous robot mop 100 . the overall shape and configuration of the robot may affect its ability to autonomously clean and navigate an environment , but generally does not affect , nor is affected by , the automated floor - mopping aspects of this invention . fig2 is an exploded view of the robot mop 100 embodiment shown in fig1 . wires , hardware and other components have been removed in the view of fig2 for simplification . in one embodiment , the robot is housed inside a plastic shell 101 , and controlled by a custom computer assembly 102 that includes a central processing unit ( cpu ) or processor , random access memory ( ram ), and non - volatile storage . there are many cpus that are sufficient for use including , for example , those manufactured by intel , motorola , and microchip ( pic ). the computer assembly 102 processes information received from sensors 103 to determine its position , the room types and so on , in order to determine what should be done next . additionally , the computer assembly 102 controls all the motors on the robot in one embodiment . information about the environment , such as a map and task schedule , is maintained in non - volatile memory . the computer assembly 102 includes two camera sensors 103 that view through lenses 104 to provide stereo vision . wide angle lenses such as those found in some readily available web and security cameras are preferred in this embodiment . while cameras are the sensors in one embodiment , the robot can also use ultrasonic , radar or lidar sensors in place of or in conjunction with the cameras . the cameras are the primary sensors facing the forward direction , and additional cameras or other sensors may optionally be oriented around the periphery of the robot . the robot may also use short range ultrasonic or touch sensors , floor type sensors or other additional ways to improve its performance . a left drive wheel and drive motor assembly 107 and a right drive wheel and drive motor assembly 108 mounted on a bracket 109 within the shell propel the robot 100 . a battery 106 powers the system . ideally , the battery 106 provides sufficient voltage for the computer , sensors and motors . otherwise , the system may require one or more transformers . in one embodiment , a rechargeable battery is utilized and is sized to provide an hour or more of power for the robot to effectively clean between charges . nicad , lithium ion , lead acid and other battery technologies may be successfully used . the mopping system is mounted on a bottom plastic shell 110 . it includes a pre - moistened web or towel 115 assembled onto a feed roll , reel or roller 116 and a take - up roll 117 . the entire towel assembly is configured in a manner similar to a scroll where the paper is wound from one roll onto the other roll . the ends of both rollers 116 , 117 have details that snap into mating features 119 on the lower shell 110 . one end of the take - up roll has a gear 118 that meshes with a gear 112 mounted on a towel drive motor 111 . when the towel 115 is in place within the robot 100 , the cleaning area passes over a non - absorbent cushioning pad 114 adhered to a mounting plate 113 , which may be a solid mounting plate . one or more weights 105 may be added to the robot system to ensure that the towel 115 is pressed against the floor with an appropriate pressure . in one embodiment , closed cell foams are utilized for the pad because they are durable and do not absorb water . however , self - skinning open cell foams such as urethane and neoprene are acceptable as are other sponge type materials enclosed in a watertight bag . as the robot 100 moves back and forth across the floor of an area or room , the towel 115 mops the floor . during use , the towel is transferred between the feed reel 116 and the take - up reel 117 at a controlled rate . tests indicate that one square foot of towel can clean approximately 25 square feet of floor . the computer assembly 102 can advance the towel a specific amount based on the amount of floor that is cleaned . alternatively , the robot 100 could include a sensor , such as a camera , to determine when the active cleaning area of the towel is dirty . one embodiment uses one motor 111 on the take - up reel 117 and assumes there is sufficient friction on the feed reel 116 to prevent it from inadvertently unwinding in use . alternate embodiments can include drive motors on both rollers and / or clutches or friction brakes to ensure tension on the towel . in one embodiment , the towel 115 is embodied in a disposable assembly that snaps into the robot and is removed when the entire length has been used . a paper - based towel similar to a paper towel or a handiwipe ™ is used in one embodiment , but a cloth towel is an alternative . alternatively , a non - disposable cloth towel could be removed and washed between uses . regardless of the material , the towel is to be pre - moistened . adding soap or other cleaning agent to the mixture improves the cleaning characteristics . similarly , the towel could be pre - moistened with a wax so as to wax , rather than mop , a floor . in many embodiments , a length of the towel on the roll is independent of the amount of towel needed to clean the floor . therefore , the towel may remain on the robot mop for an indefinite period . for these embodiments , it may be preferable to encase the feed roll in a watertight compartment including a seal around where the towel exits the compartment . this will enable the towel to remain wet between uses . minimizing the robot size allows it to clean smaller spaces . however , the smaller the robot , the smaller the towel roll it can carry and the smaller the amount of floor it can clean before the towel needs replacing . an alternative is to provide a large roll of toweling and have the robot automatically load a length of towel as required . the robot can either load a standard length , or it could determine the amount it needs for a day and take that amount . in such an automated system , the robot disposes of the dirty towels . as shown in fig3 the use of the non - absorbent pad 121 ( which is similar to the pad 114 ) offers several improvements to previous cleaning devices . it provides a relatively large cleaning surface and ensures constant pressure when the towel 122 ( which is similar to towel 115 ) is pressed against a surface or floor 120 . the towel is transported from a feed roller 123 to a take - up roller 124 in one embodiment , the pad 121 , the towel 122 , the feed roller 123 , the take - up roller 124 , and drive wheels 125 ( only one wheel is shown ) are configured in a robot housing 126 as shown . in another embodiment , the position of the feed roller and the take - up roller may be interchanged . since the pad is soft and compliant in one embodiment , it conforms to irregularities in the floor , such as grout lines 127 in tile flooring . this feature improves the cleaning ability of the robot mopping system . fig4 shows a top perspective view ( fig4 b ) and bottom perspective view ( fig4 a ) of a remotely controlled mopping device 130 . this device 130 includes a pre - moistened cleaning towel 131 , a non - absorbent cushioning pad 132 and a drive system 133 mounted in a plastic shell 134 . however , the mopping device 130 does not include the sensors and electronics to autonomously navigate through its environment . a person using a joystick or other similar controller could control this device in a manner similar to that done with toy cars . alternatively , the mopping device could be a slave robot in a master / slave system 142 such as shown in fig5 . in this configuration , the mop 141 ( which is similar to the mopping device 130 ) performs the cleaning under the control of the master robot 140 . the master robot 140 includes most or all of the electronics and sensors , and directs the slave &# 39 ; s movement such as described in applicant &# 39 ; s copending u . s . patent application ser . no . 09 / 449 , 177 , filed on nov . 24 , 1999 , entitled “ autonomous multi - platform robot system ”, which is hereby incorporated by reference . in this system 142 , a single control robot such as master robot 140 could work with multiple cleaning devices , such as sweepers and vacuums . it is possible for the master controller to be a stationary computer provided there are sufficient sensors for it to track the slave device throughout a house or other building . referring again to fig4 a leading ( or trailing ) wheel 135 that is not on the same axis as the drive system 133 may be incorporated into the robot or remote device to improve the drive system . in such a three wheel system , or alternatively , in a four or more wheel system , the robot or remote device is balanced better than a two wheel system and the extra wheel ( s ) provides a limit as to how much the absorbent pad 132 can be compressed by the weight of the robot or device 130 . therefore , such ( wheels in more than one axis ) configurations provide for the absorbent pad 132 to be compressed by a specific and constant amount . alternatively , the foam pad 132 can be weighted or spring loaded to apply a specific and constant cleaning pressure to the towel that is less than the weight of the entire robot 130 . as shown in fig6 it is possible to remove the non - absorbent pad , such as pad 121 shown in fig3 and have either the feed roll 150 or the take - up roll 151 directly contact the floor as in similar non - automated systems . the robot housing 152 and the entire robot system is designed to adjust for the change in size of the towel roll . in one embodiment , the housing adapts mechanically because the height of the contact area changes as the towel is transferred between rolls . electronically , the feed rate also varies because the effective cleaning head changes size during use . fig7 a and 7 b show an embodiment where a motor 162 and lead screw 161 raise the non - absorbent pad from a lowered position 160 ( fig7 a ) to a raised position 164 ( fig7 b ) when the device is not mopping . in this embodiment , the robot mop rides on a skid pad 163 , or a trailing wheel , when the pad is raised . this configuration enables the robot to traverse a floor , such as carpet , without mopping it . raising the pad to position 164 also helps the robot move if it gets stuck or if the wheels slip . in an alternate embodiment , the robot can automatically load the towel from a base station . the system can either change an entire towel cartridge , or can wind the towel from a large roll using a feed mechanism similar to a movie projector or printer . in this situation , the robot can calculate and the load the amount of towel required to mop the floor . specific blocks , sections , devices , functions and modules may have been set forth . however , a skilled technologist will realize that there are many ways to partition the system of the present invention , and that there are many parts , components , modules or functions that may be substituted for those listed above . while the above detailed description has shown , described , and pointed out the fundamental novel features of the invention as applied to various embodiments , it will be understood that various omissions and substitutions and changes in the form and details of the system illustrated may be made by those skilled in the art , without departing from the intent of the invention .
a floor mopping assembly finding use in a cleaning robot . the cleaning robot may be remotely controlled or autonomous . in one embodiment , a feed roller lets out a roll of webbing or toweling , a take - up roller reels in the toweling , and a motor system causes transfer of the toweling between the feed roller and the take - up roller . a housing holds the motor system and the rollers , which are mounted in the housing such that the motor causes transfer of the webbing between the rollers . one of the rollers is configured to rest on the floor or surface so as to cause the toweling to clean the surface . in an alternative embodiment , the assembly also includes a pad to press the toweling against the surface , where the pad is mounted in the housing such that the motor causes transfer of the toweling between the rollers and between the pad and the surface .