Patent Description:
Industrial and commercial floors are cleaned on a regular basis for aesthetic and sanitary purposes. There are many types of industrial and commercial floors ranging from hard surfaces such as concrete, terrazzo, wood, and the like, which can be found in factories, schools, hospitals, and the like, to softer surfaces such as carpeted floors found in restaurants and offices. Different types of floor cleaning machines such as scrubbers, sweepers, and extractors, have been developed to properly clean and maintain these different floor surfaces.

For example, a typical industrial or commercial scrubber is a walk-behind or drivable, self-propelled, wet process machine that applies a liquid cleaning solution from an on-board cleaning solution tank onto the floor through nozzles. Rotating brushes forming part of the scrubber agitate the solution to loosen dirt and grime adhering to the floor. The dirt and grime become suspended in the solution, which is collected by a vacuum squeegee fixed to a rearward portion of the scrubber and deposited into an onboard recovery tank.

Floor cleaning machines can also be designed as unmanned, robotic units that operate autonomously. However, there are particular challenges in automating the cleaning process of an autonomous scrubber, particularly for large, industrial or commercial floor cleaning machines that can be employed unsupervised in areas where there is pedestrian traffic. In addition to providing an adequate guidance or navigation system that prevents the unmanned, robotic unit from engaging objects or entering prohibited areas, the cleaning operation itself must be managed to ensure the unmanned, robotic unit is actually performing the cleaning operation as intended. Similarly, during manned operation of floor cleaning machines, it can sometimes be difficult for the operator to visually or manually recognize a potential deficiency in the cleaning process.

<CIT> discloses an autonomous floor cleaning robot carrying a supply of cleaning fluid and being arranged to apply cleaning fluid to the floor and to thereafter collect the fluid after it has been used to clean the floor.

<CIT> discloses a wet extraction type carpet cleaner with means to indicate to a user that recovered liquid in a recovery tank has reached a predetermined level.

The present inventors have recognized, among other things, that a problem to be solved with floor cleaning machines is the inability to recognize when the cleaning operation is deficient, potentially failing or failing. In particular, a problem to be solved with autonomous or robotic floor cleaning machines is that such machines often cannot automatically detect conditions of the cleaning process that might require corrective action. Such conditions are frequently recognizable by a user of manually operated floor cleaning equipment. However, sometimes it can even be difficult for manual operators of floor cleaning equipment to recognize when the cleaning operation may be deficient. For example, in manually operated floor cleaning equipment, the operator typically sits in front of a recovery system looking forward and is not looking back for water trailing. Furthermore, water trailing from deficient squeegee blades or vacuum recovery systems can result in streaking of the floor that is difficult to visually perceive.

The present subject matter can help provide a solution to these and other problems such as by providing a robotic or autonomous cleaning machine that can include a control system to monitor the status of the cleaning operation. For example, the control system can be connected to a sensor system connected to the cleaning machine that can determine the presence of moisture left behind by the cleaning machine.

In an example, a floor cleaning machine can comprise a chassis, a cleaning mechanism, a liquid system, a recovery system, a control system, and a cleaning operation sensing system. The chassis can be configured for movement along a cleaning path. The cleaning mechanism can be connected to the chassis to perform a cleaning operation. The liquid system can be connected to the chassis to provide liquid to the cleaning mechanism. The recovery system can be connected to the chassis to recover liquid from the cleaning operation. The control system can be connected to the floor cleaning machine to control performance of the cleaning operation. The cleaning operation sensing system can be connected to the control system to detect a condition of the cleaning operation.

In another example, a moisture detection system for a floor cleaning machine configured to drive along a cleaning path can comprise a frame, electrodes, and a sensor electronics system. The frame can be connected to a cleaning machine. The electrodes can be connected to the frame for engaging moisture along the cleaning path. The sensor electronics system can be connected to the electrodes to determine presence of moisture at the electrodes.

In yet another example, a floor cleaning machine can comprise a chassis, a cleaning mechanism, a liquid system, a recovery system, a control system, and a water trailing detection system. The chassis can have a forward end and an aft end and can be configured for movement along a cleaning path. The cleaning mechanism can be connected to the chassis to perform a cleaning operation. The liquid system can be connected to the chassis to provide liquid to the cleaning mechanism. The recovery system can be connected to the chassis aft of the cleaning mechanism to recover liquid from the cleaning operation. The control system can be connected to the floor cleaning machine to control performance of the cleaning operation. The water trailing detection system can comprise: a frame connected to the chassis aft of the recovery system; an absorbent medium connected to the frame; and a moisture sensor in communication with the control system and configured to alter a signal in response to moisture in the absorbent medium.

<FIG> is a front perspective view of floor cleaning machine <NUM> having optical sensors 12A and 12B, distance sensors 14A and 14B, and a status light system <NUM>. <FIG> is a rear perspective view of floor cleaning machine <NUM> of <FIG> showing control panel <NUM>, operator platform <NUM>, and trailing mop system <NUM>. Machine <NUM> can include chassis <NUM> to which wheels 26A, 26B and <NUM> can be connected. Chassis <NUM> can support various cleaning devices, such as trailing mop system <NUM>, forward mop system <NUM>, scrubber <NUM> and squeegee <NUM>. Chassis <NUM> can be connected to or form part of platform <NUM>. Control panel <NUM>, which can operate scrubber <NUM>, squeegee <NUM> and trailing mop system <NUM>, can be in electronic communication with remote device <NUM> and display <NUM> (<FIG>). <FIG> and <FIG> are discussed concurrently.

Floor cleaning machine <NUM> can be configured to clean, treat, scrub, or polish a floor surface, or perform other similar actions using, for example, trailing mop system <NUM>, scrubber <NUM> and squeegee <NUM>. An operator can stand on platform <NUM> and control machine <NUM> using control panel <NUM> and steering wheel <NUM>. Alternatively, optical sensors 12A and 12B and distance sensors 14A and 14B, as well as laser scanner <NUM> and personnel detectors 37A - 37C, can allow machine <NUM> to autonomously drive itself. The present application describes various features that can be used to facilitate autonomous cleaning and autonomous driving of machine <NUM>. The features described in the present application can be applied to any type of floor cleaning equipment, such as scrubbers, sweepers, and extractors, whether autonomous or user operated.

Platform <NUM> can support the weight of an operator in a standing position. In other examples, machine <NUM> can be configured to accommodate a sitting operator. Machine <NUM> can be of a three-wheel design having two wheels 26A and 26B generally behind the center of gravity of machine <NUM> and one wheel <NUM> in front of the center of gravity. In an example, platform <NUM> can be located behind the center of gravity. Front wheel <NUM> can be both a steered wheel and a driven wheel. Front wheel <NUM> can have a device for determining the angular position of the driving direction about the steering axis. In an example, rear wheels 26A and 26B are not driven but have one or more devices, such as encoders 27A and 27B, respectively, for determining speed of rotation each wheel. The angular position of each wheel 26A and 26B, and the angular position and steering angle of wheel <NUM> can be used to determine the position of machine <NUM> relative to objects sensed by optical sensors 12A and 12B and distance sensors 14A and 14B, as well as laser scanner <NUM>, in mapping an environment of machine <NUM>.

Machine <NUM> can be electrically operated and can include a battery (e.g., battery <NUM> of <FIG>) for powering the various components of machine <NUM>. Motors (not shown) within machine <NUM> or steering wheel <NUM> can be used to turn wheel <NUM>, such as during autonomous operation of machine <NUM>. Additionally, wheel <NUM> can be connected to a prime mover, such as an electric motor (e.g., motor <NUM> of <FIG>), that provides propulsive force to machine <NUM>.

Scrubber <NUM> can be configured to provide a cleaning action to the floor, such as rotary disc, orbital or cylindrical cleaning. In other examples, machine <NUM> can be configured to have a cleaning mechanism that provides other cleaning action, such as suction or vacuum cleaning actions. Fluid from a liquid cleaning system disposed within main cowling <NUM> can be dispensed by machine <NUM> to facilitate scrubbing performed by scrubber <NUM>. A liquid system can include a liquid storage tank, a pump system, and spray nozzles, as discussed below. Squeegee <NUM> can be used to corral or wipe dirty fluid behind scrubber <NUM> and can be connected to a recovery system having a tank (e.g., tank <NUM> of <FIG>) disposed within main cowling <NUM>. A recovery system can include a suction tube (e.g., hose <NUM>), a suction motor (e.g., motor <NUM>), and a storage tank (e.g., tank <NUM>).

Optical sensors 12A and 12B, distance sensors 14A and 14B, and laser scanner <NUM>, as well as the other sensors described herein, can be collectively referred to as a guidance or navigation system for machine <NUM> when operatively connected to control panel <NUM> as described herein. Machine <NUM> can also include other types of sensors to facilitate autonomous guidance, such as ambient light sensors. Optical sensors 12A and 12B can comprise video cameras that can record the environment of machine <NUM>. Distance sensors 14A and 14B can comprise active ultrasonic sonar sensors or laser sensors that can generate highfrequency sound waves and evaluate the echo which is received back by the sensor, measuring the time interval between sending the signal and receiving the echo to determine the distance to an object. Laser scanner <NUM> can generate three-dimensional data of the space around machine <NUM>.

Control panel <NUM> can be connected to electronics programmed to generate mapping of locations that machine <NUM> has visited. Thus, as machine <NUM> is used throughout a facility, control panel <NUM> can add new places to the map and continuously refine the mapping of existing places, using the angular position of wheels 26A, 26B and <NUM>. Machine <NUM> can use optical sensors 12A and 12B, distance sensors 14A and 14B, and laser scanner <NUM> to recognize the surroundings of machine <NUM> to place machine <NUM> into the mapped area. Both two-dimensional and three-dimensional mapping can be logged into memory of electronics connected to control panel <NUM>. Thus, routes for the cleaning paths of vehicle <NUM> can be recorded in the mapped area for various cleaning operations. The cleaning path routes can be generated by an operator of machine <NUM> or automatically by control panel <NUM>. Machine <NUM> can provide an indication to an operator regarding the status of the location of machine <NUM> relative to the mapped area. For example, status light system <NUM> can light up in a particular pattern or color to indicate that machine <NUM> is in a known location, is currently mapping a new location, is paused, or some other such indication.

Status light system <NUM> can be provided to communicate various statuses of machine <NUM> to the operator, other personnel or other pedestrians in the line-of-sight of machine <NUM> and status light system <NUM>. Status light system <NUM> can include one or more visual indicators, such as light-emitting diodes (LEDs) or other light sources. The light bulbs can be positioned behind lens <NUM> to convey information to people in proximity of machine <NUM>. For example, a solid white light can indicate that the machine is ready for operation, green can indicate that machine <NUM> is actively and correctly performing a cleaning operation, a flashing blue light on one side of machine <NUM> can indicate that machine <NUM> is about to make a turn to the side of the flashing blue light, a yellow light can indicate that machine <NUM> has stopped the cleaning process because of a detected or sensed condition, and a red light can indicate that machine <NUM> is malfunctioning or has stopped operating. Other types of indicators can also be used to convey information to close-by people, such as digital text displays or audio alarms from a loudspeaker, such as voice prompts and horn sounds. Status light system <NUM> can be connected to control panel <NUM> to receive information from sensors in machine <NUM> to provide predictive turning information to bystanders. For example, if an object is sensed in the path of machine <NUM> and control panel <NUM> calculates that the path of machine <NUM> needs to be rerouted, status light system <NUM> can be used to provide information to a bystander that machine <NUM> will be changing path.

While machine <NUM> is in a robot or autonomous operating mode, it can be desirable to monitor and facilitate the driving and cleaning operations being executed by the various systems of machine <NUM>. During user operation of machine <NUM>, an operator drives machine <NUM> to maintain the cleaning path and avoid colliding with stationary and moving objects that are or can potentially become in the driving path of machine <NUM>. Likewise, during user operation of machine <NUM>, an operator is present to utilize sensory input to monitor the cleaning process, such as by watching for small objects in the cleaning path or observing torn squeegees or failing scrub pads. However, during autonomous operation, machine <NUM> can include various sensing and monitoring equipment as well as various supplementary cleaning equipment to ensure machine <NUM> autonomously drives in a safe manner and to ensure the cleaning operation continues in a proper and efficient manner. Machine <NUM> can include remote device <NUM> that can be carried by a remote operator of machine <NUM> to receive updates on the operation of machine <NUM> from communication link <NUM> of control panel <NUM>, or directly from a sensor, or to provide command instructions to control panel <NUM> or machine <NUM>. For example, remote device <NUM> can comprise fob <NUM> that can communicate with control panel <NUM> via a wireless connection using communication link <NUM> to convey information via indicators 44A, 44B and 44C or provide instructions via button <NUM>.

In an example, trailing mop system <NUM> can be used to absorb residual moisture left behind by squeegee <NUM>, if any. Trailing mop system <NUM> can include frame member <NUM> (<FIG>) that is connected to chassis <NUM> of platform <NUM> via mounting system <NUM> (<FIG> and <FIG>), which can include a bracket mechanism or a motor. Squeegee <NUM> may become compromised such that dirty water from scrubber <NUM> is not properly transferred to the recovery system by squeegee <NUM>. As such, in the case of autonomous operation of machine <NUM>, it might not become noticed by an operator not at the site of machine <NUM> that liquid is being left behind. As such trailing mop system <NUM> can be used to absorb undesirable liquid trailing behind machine <NUM> during operation. Furthermore, trailing mop system <NUM> can include a sensor (e.g., sensor <NUM> of <FIG> and <FIG>) that can alert machine <NUM> or an operator having remote device <NUM> in electronic communication with machine <NUM> of the presence of liquid in trailing mop system <NUM>. Likewise, forward mop system <NUM>, which can be used for pre-sweeping operations, can also be provided with a moisture detection system as described herein, such as sensor <NUM> and brush <NUM>. As such, a remote operator of machine <NUM> can be alerted to the possible compromise of a squeegee blade (e.g. blade <NUM> of <FIG>) in squeegee <NUM>, or entry of machine <NUM> into an area where there is water present on the floor and should not be.

As will be discussed in greater detail with reference to <FIG>, machine <NUM> can be outfitted with a variety of different instruments, systems, sensors and devices to enable and improve the autonomous operation of machine <NUM>. Examples of machine <NUM> described herein can improve the efficiency of the cleaning or treating operation such as by reducing or eliminating deficient cleaning procedures and executing a consistent cleaning or treating operation, free of variability that can be introduced from procedure imperfections or operator error or variability.

<FIG> is a side view of floor cleaning machine <NUM> of <FIG> and <FIG> showing various sensors and cleaning devices that can be used to automate operation and cleaning of floor cleaning machine <NUM>. <FIG> is an exploded view of floor cleaning machine <NUM> of <FIG> showing the location of the various sensors and cleaning devices of <FIG>.

Machine <NUM> can include various supplementary cleaning devices, such as trailing mop system <NUM> and forward mop system <NUM>. Machine <NUM> can also include various hardware and sensors to facilitate and monitor the cleaning and driving operations of machine <NUM>, such as camera <NUM>, moisture sensor <NUM>, current sensor <NUM>, pressure sensor <NUM>, and sound sensor <NUM>.

During a cleaning operation of machine <NUM>, motor <NUM> of a propulsion system can be actuated to roll wheel <NUM> along the floor surface to be cleaned. While machine <NUM> is rolling on wheels 26A, 26B and <NUM>, motor <NUM> of scrubber <NUM> can be activated to rotate scrubbing pad <NUM>. Cleaning solution or liquid can be added to a storage space within main cowling <NUM> through cap <NUM>. Cleaning solution or liquid can be dispensed from within main cowling <NUM> to the area of scrubbing pad <NUM> via an actuator valve or nozzle system (not shown), preferably to an area forward of scrubbing pad <NUM> or on top of scrubbing pad <NUM>. Suction hose <NUM> can be connected to squeegee <NUM> to vacuum up dirty cleaning solution behind scrubbing pad <NUM> and in front of the squeegee blade <NUM>. Vacuum motor <NUM> draws the dirty cleaning solution into tank <NUM>. Vacuum motor <NUM> can also be used to pump dirty cleaning solution out of tank <NUM> via hose <NUM>. Motors <NUM>, <NUM> and <NUM> can receive power from battery <NUM>. Control panel <NUM> can include electronics that can be used to operate motors <NUM>, <NUM> and <NUM>. The electronics of control panel <NUM> can also be used to operate various sensors and devices on machine <NUM> to ensure that the dispensing system, scrubber <NUM>, squeegee <NUM> and the recovery system are functioning correctly and performing a proper cleaning operation.

Machine <NUM> can include various sensors or devices for detecting whether or not various cleaning instruments, components, sensors or other devices are performing as desired within to machine <NUM>. In particular, various sensors can be used to detect different conditions that can provide an indication of the performance of the recovery system.

For example, machine <NUM> can include current sensor <NUM>. Current sensor <NUM> can be configured to monitor current flow in motor <NUM>, which is used to control the amount of vacuum or suction generated in hose <NUM>. A change in the sensed current can indicate that debris is lodged under squeegee blade <NUM> or that squeegee blade <NUM> is compromised, or some other condition. If the current level goes down, this can be an indication that that there is a leak, as motor <NUM> will need to draw less current and work less hard to provide suction. If the current level goes up, this can be an indication that there is a blockage of suction hose <NUM>, as motor <NUM> will need to draw more current to work harder in an attempt to overcome the blockage. Current sensor <NUM> can comprise any suitable sensor as is known in the art. In an example, current sensor <NUM> can be configured to detect alternating current (AC) or direct current (DC) in a wire, and generate a signal proportional to the detected current. Examples of current sensors include Hall effect integrated circuit sensors, transformer or current clamp meters, fluxgate transformer type sensors, resistors, and fiber optic current sensors.

In the illustrated example, current sensor <NUM> can be located on a non-moving component of motor <NUM>, such as housing <NUM>, or in close proximity to motor <NUM>. Alternatively, current sensor <NUM> can be included in electronics within control panel <NUM>. Current sensor <NUM> can be in electronic communication with control panel <NUM> and can send a signal to electronics within control panel <NUM> based on the monitored magnitude of the sensed current running to and/or from motor <NUM>. If control panel <NUM> receives an indication that the current of motor <NUM> has changed from a typical steady-state operation current level, which can indicate that squeegee blade <NUM> has developed a leak or has become otherwise breached during the cleaning operation, control panel <NUM> can send a wireless signal to remote device <NUM> to notify a remote operator of machine <NUM>, or can provide an indication of the sensed condition at display <NUM>. Additionally, control panel <NUM> can stop operation of one or both of scrubber <NUM> and machine <NUM>.

Additionally, machine <NUM> can include pressure sensor <NUM>. Pressure sensor <NUM> can be configured to monitor suction in front of squeegee blade <NUM>, such as at inlet port <NUM>. A change in the sensed vacuum can indicate that debris is blocking inlet port <NUM> to suction hose <NUM>, or some other condition. Depending on where a leak or blockage occurs, a rise or fall in the suction level can be an indication that that there is a leak or a blockage. Pressure sensor <NUM> can comprise any suitable sensor as is known in the art. In an example, pressure sensor <NUM> can be configured to detect absolute, differential, gage, and vacuum pressure, and generate a signal proportional to the detected pressure or vacuum.

Pressure sensor <NUM> can be located on a frame member of squeegee <NUM>, such as squeegee cover <NUM>, in close proximity to blade <NUM>. In the illustrated example, pressure sensor <NUM> can also be mounted directly to hose <NUM>, such as near where hose <NUM> couples to inlet port <NUM>. Pressure sensor <NUM> can be in electronic communication with control panel <NUM> and can send a signal to electronics within control panel <NUM> if a change in the vacuum level is detected. If control panel <NUM> receives an indication that the suction level of motor <NUM> went down from a typical steady-state operation suction level, which can indicate that squeegee blade <NUM> has developed a leak or has become otherwise breached during the cleaning operation, control panel <NUM> can send a wireless signal to remote device <NUM> to notify a remote operator of machine <NUM>, or can provide an indication of the sensed condition at display <NUM>. Additionally, control panel <NUM> can stop operation of one or both of squeegee <NUM> and machine <NUM>.

Additionally, machine <NUM> can include sound sensor <NUM>. Sound sensor <NUM> can be configured to monitor auditory noises near squeegee blade <NUM>. A change in the sensed noise level can indicate that debris is blocking inlet port <NUM> to suction hose <NUM>, or some other condition. Depending on where a leak or a blockage occurs, a rise or fall in the pitch of the sound can be an indication that that there is a leak or a blockage. Sound sensor <NUM> can comprise any suitable sensor as is known in the art, such as a microphone. In an example, sound sensor <NUM> can be configured to detect vibration or acoustic waves, and generate a signal proportional to the detected sound wave.

In the illustrated example, sound sensor <NUM> can be located on a frame member of squeegee <NUM>, such as squeegee cover <NUM>, in close proximity to blade <NUM>. Sound sensor <NUM> can also be mounted directly to hose <NUM>, such as near where hose <NUM> couples to inlet port <NUM>. Sound sensor <NUM> can be in electronic communication with electronics within control panel <NUM> and can send a signal to control panel <NUM> if a change in the volume or pitch of the sensed sound is detected. If control panel <NUM> receives an indication that the sound level of motor <NUM> went down from a typical steady state operation suction level, which can indicate that squeegee blade <NUM> has developed a leak or has become otherwise breached during the cleaning operation, control panel <NUM> can send a wireless signal to remote device <NUM> to notify a remote operator of machine <NUM>, or can provide an indication of the sensed condition at display <NUM>. Additionally, control panel <NUM> can stop operation of one or both of squeegee <NUM> and machine <NUM>.

Machine <NUM> can include camera <NUM> (<FIG> & <FIG>), which can be configured to provide a plurality of different inputs to control panel <NUM>. In an example, camera <NUM> comprises a rear-facing optical camera that can capture a visible spectrum image of the floor behind squeegee <NUM> or machine <NUM>. The visible spectrum image can be sent to control panel <NUM>, which can forward the image to a remote operator for viewing, such as by using remote device <NUM>, or can be shown on display <NUM>. Additionally, the image can be sent, for example, as a text message to a cell phone at periodic intervals, or can be available as a live stream for continuous monitoring. Other types of images, such as infrared (IR) or ultraviolet (UV), can also be captured and sent to a remote operator. In another example, camera <NUM> can be configured to monitor the floor with spectroscopy. A spectroscope can be configured to shine near-infrared light onto the floor. By analyzing the light that is reflected back to camera <NUM>, unique optical signatures can be identified that indicate water on the floor. Additionally, the images and optical signatures can be compared to reference images and signals stored in a library or database stored in control panel <NUM> so that control panel <NUM> can conduct an automated comparison of the data obtained from the live cleaning process to reference data taken from a reference cleaning operation where the cleaning operation is occurring as intended, e.g., without any, or any significant, water trailing.

In another example, camera <NUM> can comprise a thermal imaging device to detect differences in temperature behind machine <NUM>. Water left behind by squeegee <NUM> can be indicated by cooler temperatures. Water left behind by squeegee blade <NUM> that has become compromised or cut, or large debris stuck under blade <NUM> can appear as a streak on the thermal image.

Some monitoring techniques, including but not limited to IR, UV, polarization, and spectroscopy, can be used to produce an electronic image, which can be stored in memory of control panel <NUM>. The detected image can be compared with a visible spectrum image stored in memory of control panel <NUM> in order to avoid false positive detections of trailed water from imperfections in the floor, or patterns in the floor that could be interpreted as streaks by one or the other type of image. In an example, it can be advantageous to "negative" (e.g., color inverse) the image in the visible spectrum to provide contrast for comparison with other electronic images. These techniques can be used to avoid false detection of tile grout lines, paint stripes, etc. as water trails.

In various examples, a tracing element can be mixed with the cleaning solution to enhance detection of trailed water. For example, an optical brightener which fluoresces in UV light can be added to the cleaning solution. A UV emitting device can project behind squeegee <NUM> and a detecting device (e.g., camera <NUM>) can determine the level of fluorescing. Similarly, an agent that can be detected by an olfactory sensor can be added to the cleaning solution. Water trailing can be indicated when a predetermined level of detection is reached.

In examples of a water trail detection system, absorbent material <NUM> can be extended across the width of the cleaning path, across the width of squeegee <NUM>, or across some other width, and can be positioned behind the path of squeegee <NUM> or behind platform <NUM>, such as by using trailing mop system <NUM>. In other examples, absorbent material <NUM> can extend across less than the entire cleaning path or width of squeegee <NUM>. Materials suitable for absorbent material <NUM> can include, but is not limited to, absorbent foam, sponge, microfiber, cotton, wool, or a combination of materials. Absorbent material <NUM> can be mounted to a holder or frame member <NUM> behind squeegee <NUM> or behind platform <NUM>. Absorbent material <NUM> can be in the form of a rectangular strip that extends approximately across the width of the cleaning path in one dimension, and absorbent material <NUM> can be between about <NUM> inch (-<NUM>) to about <NUM> inches (~<NUM>) in the other dimension. Absorbent material <NUM> can serve to wipe small amounts of trailed water. In an example, moisture sensor <NUM> can be in fluid communication with absorbent material <NUM> to indicate if the material reaches a predetermined moisture level, which may suggest that an unacceptable amount of water is trailing machine <NUM>. Absorbent material <NUM> can also be in the form of a roller. Further description of the water trail detection system and trailing mop system <NUM> are provided with reference to <FIG>.

<FIG> is a top perspective view of trailing mop system <NUM> of <FIG> showing a close-up of frame member <NUM>, absorbent material <NUM> and sensor <NUM>. <FIG> is a top perspective view of frame member <NUM> of <FIG> showing a portion of mounting system <NUM> for connecting trailing mop system <NUM> to chassis <NUM> of machine <NUM>. <FIG> is a bottom view of frame member <NUM> of <FIG> and a top view of absorbent material <NUM> of <FIG> removed from frame member <NUM> to show first and second electrode strips 84A and 84B mounted to frame member <NUM>. Frame member <NUM> can be connected to machine <NUM> using mounting system <NUM>. Absorbent material <NUM> can be connected to frame member <NUM> using any suitable fastening methods, such as threaded fasteners, adhesive, or hook and loop fastener material strips 86A and 86B.

Frame member <NUM> can have a width at least as wide as scrubber <NUM> or squeegee <NUM>, but can be less than the width of scrubber <NUM> or squeegee <NUM>. However, frame member <NUM> can be as wide as the width of machine <NUM> or the distance between wheels 26A and 26B. Trailing mop system <NUM> and frame member <NUM> can be mounted to chassis <NUM> in any suitable manner, either in a fixed manner or an adjustable manner, such as by using mounting system <NUM>. Mounting system <NUM> can include, brackets 87A and 87B and pin <NUM>. For example, frame member <NUM> can be connected to bracket 87A having pin <NUM>, which can couple to bracket 87B connected to chassis <NUM> or platform <NUM>. Bracket 87B can be configured to receive pin <NUM> in a pivoting manner. Bracket 87B can be configured to raise and lower relative to chassis <NUM>, such as via a spring system or via foot pedal-operated system. Trailing mop system <NUM> can be connected to a motor mechanism (not shown) and can be raised and lowered automatically by a user-initiated input at control panel <NUM>. In other examples, trailing mop system <NUM> can be raised or lowered manually, or added and removed from chassis <NUM> manually. Weights (not shown) can be mounted to frame member <NUM> to facilitate contact between absorbent material <NUM> and the floor. Additionally, mounting system <NUM> can include springs (not shown) to maintain frame member <NUM> biased in either an upward position or a downward position.

Sensor <NUM> can include electrodes 84A and 84B, housing <NUM>, cable <NUM>, and electronics, which may be located within housing <NUM> or in electronics of control panel <NUM>. Sensor <NUM> can be provided on or in trailing mop system <NUM> to determine a moisture level in the cleaning medium or absorbent material <NUM>. Electrodes 84A and 84B can be mounted to frame member <NUM> or can be embedded within absorbent material <NUM>. Sensor <NUM> can be configured as a moisture-indicating sensor, such as by including electrodes 84A and 84B having a conductivity or capacitance that changes as more or less water is present between electrodes 84A and 84B. Thus, sensor <NUM> can comprise a conductivity sensor that provides an indication of moisture. In the illustrated embodiment, electrodes 84A and 84B are positioned between frame member <NUM> and absorbent material <NUM>. In particular, electrodes 84A and 84B can be mounted to frame member <NUM>, such as by using fasteners <NUM>. Wires can extend from electrodes 84A and 84B through frame member <NUM> to extend into housing <NUM>, which can be connected to control panel <NUM> via cable <NUM>. Electronics for operating sensor <NUM> can be located within housing <NUM> or within control panel <NUM>. Electrodes 84A and 84B extend all the way across the width of frame member <NUM> from first end 98A to second end 98B.

Absorbent material <NUM> is mounted to frame member <NUM> to span distance D between electrodes 84A and 84B. Absorbent material <NUM> additionally extends the width of frame member <NUM> from first end 98A to second end 98B. If absorbent material <NUM> is dry, sensor <NUM> can generate a baseline signal representative of the sensed conductivity or capacitance between electrodes 84A and 84B. If absorbent material <NUM> begins to accumulate moisture, e.g., water or cleaning solution, the signal generated by sensor <NUM> will deviate from the baseline signal. Sensor <NUM> can have a sensitivity level configured to indicate if squeegee <NUM> is trailing excessive water, which can be an indication of a detached or compromised squeegee blade <NUM>. For example, sensor <NUM> can send a moisture indicator signal to control panel <NUM> and control panel <NUM> can be programmed to trigger an alarm (e.g., on remote device <NUM> or display <NUM>) for an operator of machine <NUM> at a threshold that would be above incidental moisture left behind by squeegee <NUM>.

<FIG> is a close-up partial top view of absorbent material <NUM> of <FIG> showing connection strips 86B for coupling to connection strips 86A on frame member <NUM>. <FIG> is a close-up partial bottom view of absorbent material <NUM> of <FIG> showing absorbent fibers <NUM> for drawing moisture to electrodes 84A and 84B of <FIG>. As discussed above, trailing mop system <NUM> can be used as a redundant recovery system for squeegee <NUM>. Thus, trailing mop system <NUM> can include absorbent material <NUM> that can contact the floor behind blade <NUM> of squeegee <NUM> to wipe or pick up any water or fluid that may be left behind.

Absorbent material <NUM> can include absorbent fibers <NUM> and backing <NUM>, which can be connected by edge seam <NUM>. Connection strips 86A can be connected to backing <NUM> by any suitable method, such as stitching, adhesive or the like. Backing <NUM> can comprise any compliant material, such as cloth or the like. Absorbent fibers <NUM> can comprise any suitable cleaning medium such, as chamois, sponge, microfiber, or other absorbent material. Connection strips 86A can extend parallel to electrodes 84A and 84B.

Connection strips 86A can be positioned to hold absorbent material <NUM> flat between electrodes 84A and 84B so that a consistent pathway between electrodes 84A and 84B can be produced. In other examples, electrodes 84A and 84B can be attached to backing <NUM> in such a manner that the material of backing <NUM> is evenly distributed, or flat, between electrodes 84A and 84B. Electrodes 84A and 84B can be attached to backing <NUM> on the exterior of absorbent material <NUM> or can be positioned between backing <NUM> and absorbent fibers <NUM> in the interior of absorbent material <NUM>. In examples, the fabric, cloth or textile of absorbent material <NUM> can be positioned between electrodes 84A and 84B in a forward to aft direction to form a conductive path in between electrodes 84A and 84B that can influence the conductivity or capacitance therebetween, preferably in a uniform and consistent manner.

<FIG> is a perspective view of an alternative embodiment of water trailing detection system <NUM> comprising brush <NUM> having conductive bristle zones 112A and 112B. In an example, brush <NUM> can also include non-conductive bristles <NUM> so as to form a bristle strip. Bristles of conductive bristle zones 112A and 112B can be used as electrodes to sense moisture, cleaning solution or water on a floor on which machine <NUM> is performing a cleaning operation.

Conductive bristle zones 112A and 112B and non-conductive bristles <NUM> can be connected to frame <NUM>, which can include bracket <NUM>. Frame <NUM> can comprise a rigid or semi-rigid structure that can hold bristles of conductive bristle zones 112A and 112B and non-conductive bristles <NUM> into contact with a floor. Frame <NUM> can be as wide as squeegee <NUM>, scrubber <NUM> or the width between wheels 26A and 26B, or wider. Frame <NUM> can be coupled to machine <NUM> in various locations using various methods. For example, frame <NUM> can be mounted to squeegee <NUM> on the trailing side of blade <NUM>, on chassis <NUM> behind squeegee <NUM>, or on chassis <NUM> (or platform <NUM>) behind machine <NUM>. In other embodiments, non-conductive bristles <NUM> can be omitted from brush <NUM> so that only conductive bristles are included. As such, bristles of conducive bristle zones 112A and 112B can be used only to perform moisture or water trailing sensing without sweeping action. In an example, non-conductive bristles <NUM> can be replaced with a squeegee blade, such as blade <NUM>.

Bracket <NUM> can be coupled to machine <NUM> by any suitable method, such as fasteners, welding, hooks and the like. In an example, bracket <NUM> can be coupled to bracket 87B of mounting system <NUM> (<FIG>). As such, frame <NUM> can be manually adjustable or removable, or can be automatically adjustable with a motor so as to be put into contact with a floor and removed from contact with the floor.

Bristles of conductive bristle zones 112A and 112B can be connected to control panel <NUM> via any suitable methods, such as wires, so that those bristles can become electrodes. All of the bristles in each zone can be connected to each other so as to form one single large electrode zone, or each bristle, or a sub-set of bristles, can form an electrode. The illustrated example shows two conductive bristle zones, but more can be spread out across frame <NUM> to sense moisture in specific zones across the width of the cleaning path.

Control panel <NUM> can be configured to detect the conductivity or capacitance between various electrodes of brush <NUM>. If the floor between the electrodes of brush <NUM> is dry, the electrodes can generate a baseline signal, or multiple signals for different zones of electrodes, representative of the sensed conductivity or capacitance between the electrodes. If the bristles begin to come in contact with moisture, e.g., water or cleaning solution, the signal generated by brush <NUM> will deviate from the baseline signal. Conductive bristle zones 112A and 112B can have a sensitivity level configured to indicate if squeegee <NUM> is trailing excessive water, which can be an indication of a detached or compromised squeegee blade <NUM>. For example, bristle zones 112A and 112B can send a moisture signal to control panel <NUM> and control panel <NUM> can be programmed to trigger an alarm (e.g., on remote device <NUM> or display <NUM>) for an operator of machine <NUM> at a threshold that would be above incidental moisture left behind by squeegee <NUM>.

Data from any of the aforementioned monitoring methods can be analyzed by a processor within control panel <NUM>, or located remotely from machine <NUM> and in communication with control panel <NUM> via a wired or wireless communication link <NUM>, to determine if the changes meet a threshold indicating that water was left behind by squeegee <NUM>. The data can be shown in various formats to an operator of machine <NUM> via a plurality of different methods, such as graphically at display <NUM> or via indicators at remote device <NUM>. Control panel <NUM> can be configured to operate the various sub-systems, components, sensors and devices of machine <NUM> from a single location where an operator can stand on platform <NUM>. Control panel <NUM> therefore can include various hardware and software components for operating machine <NUM>. For example, control panel <NUM> can include user interface devices, processors, memory and the like for receiving input from various items, such a signals from camera <NUM>, sensors <NUM>, <NUM>, <NUM> and <NUM>, and providing output to various items, such as fob <NUM>, display <NUM> and motors <NUM>, <NUM> and <NUM>. Control panel <NUM> can include various forms of electronic memory for storing the various libraries and databases described herein, as well as programming for executing various cleaning instructions and commands, as described herein. In an example, control panel <NUM> can be implemented as a portable computing device such as a tablet computer.

Control panel <NUM> can include a wireless hub, such as wireless communication link <NUM>, that permits control panel <NUM> to communicate with devices external to machine <NUM>. Communication link <NUM> allows control panel <NUM> to access data and control other devices or autonomous machines. In one example, wireless communication link <NUM> communicates with a wireless local area network that permits communication with a local database or server at the location of machine <NUM> (e.g., within the same facility). In another example, wireless communication link <NUM> can be a Bluetooth communication device. In another example, wireless communication link <NUM> is able to connect to the Internet via various public or private signals, such as cellular or <NUM> networks and the like. Likewise, wireless communication link <NUM> can be configured to communicate directly with remote device <NUM> and fob <NUM>, or indirectly, such as through a network or Internet connection.

Also, if a moist or wet area is detected to the rear of machine <NUM>, control panel <NUM> can take corrective action in a reactive manner. If control panel <NUM> detects a moist or wet area behind of machine <NUM>, control panel <NUM> can adjust the cleaning operation to be performed by scrubber <NUM>, squeegee <NUM> or a liquid system. For example, in order to potentially rectify the water trailing detected by moisture sensor <NUM>, control panel <NUM> can increase or decrease the force with which squeegee <NUM> is pushed against the floor, increase or decrease the suction generated by motor <NUM>, increase or decrease the quantity of liquid from the liquid system, or can adjust the speed of machine <NUM>. In an example, blade <NUM> of squeegee <NUM> can be lifted off the floor and then dropped back onto the floor in an attempt to free or liberate any debris lodged between blade <NUM> and the floor. Similarly, in an example, debris can be removed from blade <NUM> by propelling machine <NUM> in reverse for a short distance, raising squeegee <NUM> a slight distance from the floor, or a combination of driving in reverse and raising squeegee <NUM>, to allow the debris to be loosened and carried into the vacuum recovery system. In an autonomous mode, corrective measures can be taken at timed intervals or at designated locations in order to preemptively reduce the occurrence of water trailing.

The autonomous or robotic and manual floor cleaning equipment described herein provide advantages over other autonomous and manual systems. More efficient autonomous operation provided by the systems and methods described herein can reduce labor costs by allowing an operator of an autonomous cleaning machine to perform other tasks while the autonomous machine operates. Additionally, the cleaning operations can be more consistently or systematically performed, such that spots are not missed or cleaning is duplicated, thereby reducing or eliminating rework. Autonomous machines can also be programmed to concentrate on high-use or particularly dirty areas rather than manual operators that tend to clean all areas equally, including those that have not been dirtied. Autonomous cleaning system are particularly advantageous for use in large open areas where the cleaning operation involves long intervals of repeated, back-and-forth operations. The systems and methods described herein facilitate and improve autonomous navigation and autonomous cleaning operations to expand the advantageous use of autonomous cleaning machines to other spaces that are not as simply cleaned as open areas. For example, systems and methods described herein allow the autonomous cleaning machine to be used in tight spaces that may utilize unique, non-repetitive route instructions or in spaces where pedestrian traffic might be present and where water trailing might frequently arise. The systems and methods of autonomous navigation and cleaning described herein can also reduce cleaning time of autonomous machines be reducing the amount of time the autonomous machine may be performing an ineffective cleaning operation, such as when a cleaning pad or squeegee blade fails.

Example <NUM> can include or use subject matter (such as a floor cleaning machine comprising: a chassis configured to move along a cleaning path; a cleaning mechanism connected to the chassis to perform a cleaning operation; a liquid system connected to the chassis to provide liquid to the cleaning mechanism; a recovery system connected to the chassis to recover liquid from the cleaning operation; a control system connected to the floor cleaning machine to control performance of the cleaning operation; and a cleaning operation sensing system connected to the control system to detect a condition of the cleaning operation.

Example <NUM> can include, or can optionally be combined with the subject matter of Example <NUM>, to optionally include a cleaning operation sensing system that can include a moisture sensor configured to detect moisture from the cleaning operation.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> or <NUM> to optionally include a moisture sensor that can comprises: a first electrode; and a second electrode spaced from the first electrode; wherein the first and second electrodes are disposed in close proximity to the cleaning path and are configured to sense the liquid from the cleaning operation.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include first and second electrodes that are mounted to the frame to extend lengthwise across at least a portion of the cleaning path.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a first electrode and a second electrode that can be connected to a mounting system that is adjustable to raise and lower the first electrode and the second electrode.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a cleaning operation sensing system that can include a trailing mop system mounted to the floor cleaning machine along the cleaning path at a rear of the floor cleaning machine, wherein the moisture sensor is mounted to the trailing mop system.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a trailing mop system that can comprise: a frame connected to the chassis; and an absorbent medium mounted to the frame to contact the first electrode and the second electrode and positioned to contact the cleaning path and absorb moisture.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a moisture sensor that can comprise: a first conductive bristle defining the first electrode; and a second conductive bristle defining the second electrode.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a first conductive bristle that can be part of a first cluster of bristles; and a second conductive bristle that can be part of a second cluster of bristles spaced from the first cluster of bristles.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a recovery system that can further comprise a squeegee blade and the first and second clusters of bristles are positioned on a trailing side of the squeegee blade.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include an absorbent pad connected to the chassis to contact the cleaning path and absorb moisture, wherein the recovery system further comprises a suction motor and the cleaning operation sensing system comprises a current sensor configured to sense current flow through the suction motor.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a recovery system that can further comprise a suction motor and the cleaning operation sensing system comprises a pressure sensor configured to sense suction generated by the suction motor.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a recovery system that can further comprise a squeegee blade and the cleaning operation sensing system comprises a sound sensor connected to the chassis proximate the blade.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a cleaning operation sensing system that can comprise a camera connected to the floor cleaning machine and configured to view the cleaning path behind the recovery system.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a camera that can comprise a thermal imaging camera.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> through <NUM> to optionally include a liquid system that can include a liquid cleaning solution and a tracing element added to the liquid cleaning solution visible by the camera.

Example <NUM> can include or use subject matter such as a moisture detection system for a floor cleaning machine configured to drive along a cleaning path comprising: a frame for connecting to a cleaning machine; electrodes connected to the frame for engaging moisture along the cleaning path; and a sensor electronics system connected to the electrodes to determine presence of moisture at the electrodes.

Example <NUM> can include, or can optionally be combined with the subject matter of Example <NUM>, to optionally include an absorbent medium connected to the frame, wherein the electrodes comprise first and second electrode strips extending across at least a portion of a width of the frame in contact with the absorbent medium, and wherein the sensor electronics system is configured to detect conductivity in the absorbent medium between the first and second electrodes.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> or <NUM> to optionally include electrodes that can comprise a plurality of bristles extending from the frame, and wherein the sensor electronics system is configured to detect conductivity between sections of the plurality of bristles.

Example <NUM> can include or use subject matter such as a floor cleaning machine comprising: a chassis having a forward end and an aft end, the chassis configured to move along a cleaning path; a cleaning mechanism connected to the chassis to perform a cleaning operation; a liquid system connected to the chassis to provide liquid to the cleaning mechanism; a recovery system connected to the chassis aft of the cleaning mechanism to recover liquid from the cleaning operation; a control system connected to the floor cleaning machine to control performance of the cleaning operation; and a water trailing detection system comprising: a frame connected to the chassis aft of the recovery system; an absorbent medium connected to the frame; and a moisture sensor in communication with the control system and configured to generate a signal in response to moisture in the absorbent medium.

Example <NUM> can include, or can optionally be combined with the subject matter of Example <NUM>, to optionally include a control system that can be configured to control autonomous movement of the chassis and autonomous performance of the cleaning operation, wherein the control system can adjust one or both of the autonomous movement of the chassis and the autonomous performance of the cleaning operation in response to receiving the signal.

Example <NUM> can include, or can optionally be combined with the subject matter of one or any combination of Examples <NUM> or <NUM> to optionally include a moisture sensor that can comprise: a first electrode extending across a first portion of a length of the cleaning path; and a second electrode extending across a second portion of the length of the cleaning path, the second electrode spaced aft of the first electrode on the frame adjacent the absorbent medium.

In embodiments, the floor cleaning machine comprises a camera, such as a thermal imaging camera. In some embodiments, the liquid system comprises a liquid cleaning solution and a tracing element added to the liquid cleaning solution visible by the camera.

In embodiments, the floor cleaning machine is configured to drive along.

In an embodiment, the floor cleaning machine comprises:.

In the just mentioned embodiment, the control system may be configured to control autonomous movement of the chassis and autonomous performance of the cleaning operation, wherein the control system can adjust one or both of the autonomous movement of the chassis and the autonomous performance of the cleaning operation in response to receiving the signal.

In the just mentioned embodiment, the moisture sensor may comprise:.

Additionally, use of the word "connected" need not imply or require that two components are directly connected to each other, but can include components connected by intermediary components.

Claim 1:
A floor cleaning machine (<NUM>) comprising:
a chassis (<NUM>) configured to move along a cleaning path;
a cleaning mechanism (<NUM>) connected to the chassis (<NUM>) to perform a cleaning operation;
a liquid system connected to the chassis (<NUM>) to provide liquid to the cleaning mechanism (<NUM>);
a recovery system (<NUM>, <NUM>) connected to the chassis (<NUM>) to recover liquid from the cleaning operation;
a control system (<NUM>) connected to the floor cleaning machine to control performance of the cleaning operation; and
a cleaning operation sensing system connected to the control system (<NUM>) to detect a condition of the cleaning operation,
characterized in that
the cleaning operation sensing system includes a moisture sensor (<NUM>) configured to detect moisture from the cleaning operation.