Patent Application
20240252703
The present disclosure is related generally to mobile service robots and, more particularly, to a mobile service robot for site disinfection.
There are many environments wherein frequent and effective disinfection of indoor spaces is required. For example, in the hospital environment, preventing Hospital Acquired Infections (HAI) is an ongoing challenge that is critical to patient safety. In addition to the patient cost, the associated financial costs are enormous. In acute care hospitals in the U.S. alone, such costs are approximately 97-147 Billion USD annually. One in ten patients worldwide is infected by an antibiotic-resistance pathogen while being treated in a hospital. This statistic does not include infections by viruses, such as SARS, MERS, SARS-COV-2 or influenza. HAI lead to 3 million infections in the USA alone, causing 48.000 preventable deaths each year.
Ultra-violet C (UVC) light from low-pressure mercury lamps, emitting strong radiation at 253.7 nm, is a well-known technology for inactivating pathogens. The germicidal efficacy of UVC is due to the fact that UVC directly disrupts the DNA or RNA in the pathogen. When enough damage is caused to the RNA or DNA, the pathogen can no longer multiply and is thus inactivated. UVC has many advantages over traditional methods for surface and room scale disinfection. It does not use chemicals and therefore does not cause resistance in pathogens or harm to the environment or personnel carrying out the disinfection process. Moreover, unlike some manual touch disinfectants like chlorine and non-touch disinfectants like hydrogen-peroxide vapor that can damage materials and surfaces, UVC like does not leave any residues and does not damage materials at low dosages.
Typical required UVC doses to achieve a desired reduction in active pathogens are shown in the following table in mJ/cm2. This table is from Malayeri, Adel & Mohseni, Madjid & Cairns, Bill. (2016). Fluence (UV Dose) Required to Achieve Incremental Log Inactivation of Bacteria, Protozoa, Viruses and Algae. IUVA News. 18. 4-6.
S Aureus (MRSA)
S Aureus (MSSA)
Acinetobacter Baumanii
Pseudomonas aeruginosa (MDR)
Enterococcus faecium
Enterococcus faecalis
Norovirus
Klebsiella terrigena
Clostridium difficile
Despite the many advantages of UVC, it is not yet widely applied because of a few key challenges. UVC light is only germicidal on surfaces that are irradiated by the UVC light. Any surfaces in shadow from the UVC light will not be disinfected. In addition, UVC is only germicidal if an adequate dosage is delivered to each surface that needs to be disinfected. The required dosage is different for each pathogen, since each pathogen exhibits a unique level of sensitivity to damage from UVC light. For this reason, UVC lamps used to disinfect surfaces and rooms in a healthcare setting have been designed to be movable in an attempt to reduce shadows and get closer to objects that need to be disinfected.
However, UVC lamps consume very significant amounts of electrical energy. A typical moveable UVC system is powered from an electrical outlet and consumes about 1-2 kW of electrical energy and needs to be powered for a significant amount of time (e.g., 30-60 min) to try to reach sufficient UVC dose delivered to space and surfaces furthest away from the lamps. For each disinfection, an operator can typically move the UVC lamps around a few times in a room to try to eliminate any shadows caused by objects in a room, such as a bed, chair or equipment. This is a laborious and error prone process. Recently, leveraging mobile service robot technology, several mobile robots have been developed that can automate the process of moving the UVC lamps around in the room to several locations, to minimize the amount of shadows and speed up operations somewhat. These systems however are limited in their use because the operation time is very limited (typically around 2 hours) and the robot is required to carry very large batteries. This results in robot UVC systems being expensive, heavy and slow to charge before being able to carry out a subsequent disinfection cycle.
Germicidal UVC lamps can be manufactured via different methods and incorporating different technologies. For example, germicidal lamps may be high pressure mercury lamps, amalgam lamps with specific properties or may use different mechanisms all together to generate (UV) light. For example, LEDs can be used to generate radiation at wave lengths other than 253.7 nm (which is specific for low pressure mercury lamps). In addition, far UVC lamps operating at 222 nm have also been shown to have germicidal effects. In this disclosure, UVC lamps should be construed to include all of these types of lamps and any other lamp technology that has a germicidal effect.
Before proceeding to the remainder of this disclosure, it should be appreciated that the disclosure may address some of the shortcomings listed or implicit in this Background section. However, any such benefit is not a limitation on the scope of the disclosed principles, or of the attached claims, except to the extent expressly noted in the claims.
Additionally, the discussion of technology in this Background section is reflective of the inventors' own observations, considerations, and thoughts, and is in no way intended to be, to accurately catalog, or to comprehensively summarize any prior art reference or practice. As such, the inventors expressly disclaim this section as admitted or assumed prior art. Moreover, the identification or implication herein of one or more desirable but unfollowed courses of action reflects the inventors' own observations and ideas, and should not be assumed to indicate an art-recognized desirability.
While the appended claims set forth the features of the present techniques with particularity, these techniques, together with their objects and advantages, may be best understood from the following detailed description taken in conjunction with the accompanying drawings of which:
Before presenting a detailed discussion of embodiments of the disclosed principles, an overview of certain embodiments is given to aid the reader in understanding the later discussion. As noted above, many situations and environments require energy-efficient and effective disinfection of indoor spaces. Typical sites include hospital and other healthcare environments, although other environments such as convalescent and food preparation environments also require high hygienic standards and minimum microbial contamination to avoid adverse human health effects.
While UVC light from low pressure mercury lamps emitting at 253.7 nm is known for inactivating pathogens at appropriate dosage levels, UVC disinfection can be time-consuming and energy-inefficient due to slow charging of mobile light sources, wasted radiation, high electrical energy consumption, and consequent limited operation time.
In an embodiment of the disclosed principles, an asymmetric robot design in employed, with emission from the robot being selective rather than uniform. For example, the robot contains a tower where UVC light sources with reflectors (e.g., either LP mercury lamps or UVC LEDs) may be placed on one side of the robot. This design focuses all available UVC power to one side of the robot (the active side), enabling the robot to approach surfaces to be disinfected along this active side. This in turn permits the robot to deliver the required UVC power on surfaces without wasting energy on other sides.
In a further embodiment of the disclosed principles, the UVC light sources may be placed as close as possible to the outermost side edges of the robot. In a further embodiment of the disclosed principles, ranging sensors (i.e., 3D cameras/3D LIDARs) are placed on the top of the tower, facing downward on the sides. This configuration provides a complete view of 270 degrees (front, side with lamps and rear) in the vicinity of the robot. With a detailed 3D view of its immediate surroundings, the robot can navigate with its lamps very close (5-10 cm) to the surfaces to be disinfected.
In another embodiment, a modular design is provided, wherein the UVC tower can be removed from the base for easy transport. With this feature, the robot and tower can be transport without needing special high clearance vehicles. The tower may be an independent unit comprising light sources and compatible electronic controllers. This tower is electrically coupled with the robot base through heavy duty power connectors available off-the-shelf, providing power to drive the lamps and signals to control the lamps. Female connectors are present at the robot base to prevent accidental contact with human users, when the tower is not connected. The electrical mating connectors are supported and held in place through mechanical support locks that can be easily removed. The connectors may include an electrical jumper on both male and female sides which provide electrical continuity only when the tower is attached to the base. This signal is connected to relays on the base. Such configuration provides implicit safety by enabling power to pass through the joint only when a tower is connected.
In a further aspect, a modular design wherein different configurations of the UVC tower are provided based on application type, i.e., low dosage disinfection on large areas as opposed to high dosage disinfection in small areas. Different tower heads can thus be mounted on a same base.
In yet a further aspect, UVC lights are placed in the bottom and/or sides of the robot, facing upwards to reach surfaces such as the bottom side of beds, tables, trolleys etc. Such placement of lamps on a robot allows for disinfection of these not-commonly used areas as well, when needed. Moreover, UVC lamps or LEDs under the robot or integrated in the wheel hubs can disinfect the wheels to prevent the wheels from carrying pathogens from one space to another. In an embodiment, lamp sources are placed at multiple heights to provide sufficient dosage at heights ranging from a significant height in human dwellings, where objects and surfaces may be present that needs to be disinfected such as 2 m, down to the ground level.
A mirror or multiple mirrors (having high UVC reflectivity) at the docking station may be used to disinfect the exterior of the robot while charging, if such areas are not disinfected by the lamps themselves while in regular use. Optionally this could be configured in a separate cabinet. Permanent placement of UVC reflective mirrors, materials or paint in certain places in a room may be used to enable UVC light to reach places that are physically not possible to reach directly from the robot.
In a further aspect of the disclosed principles, a hand-held self-contained disinfection unit is provided containing one or more UVC light sources. A battery and control circuitry are provided. A visual sensing system (wide angle cameras/3D camera/LIDAR), an inertial measurement unit and a wireless radio communication system (WiFi/Bluetooth/etc.) may also be provided. The hand-held self-contained disinfection unit can be mounted and charged from the host robot, and may communicate with the host robot using a wired or wireless radio link. This accessory may have a reflector such that the UVC light is directed away from the user. A human operator can use the hand-held self-contained disinfection unit to manually shine UVC light on required surfaces and receive guidance by audio or visual means on where to apply disinfection (which spatial location) and for how long.
With this general overview in mind, and turning now to a more detailed discussion in conjunction with the attached figures, the techniques of the present disclosure are illustrated as being implemented in or via a suitable device environment. Thus, for example,
In the illustrated embodiment, the disinfection robot 100 includes a base 101, which is supported, driven and steered by wheels 103, 105. The disinfection robot 100 includes a light tower 107, which holds one or more UVC emitting lights. The illustrated tower 107 is merely to indicate a region wherein lights may be mounted and is not intended to illustrate a particular shape or number of lights. It will be appreciated that the disinfection robot 100 may include UVC emitting lights in other positions in addition to or instead of the light tower 107.
The disinfection robot 100 includes a power source 109 such as a battery, for powering the navigation of the disinfection robot 100 as well as the one or more UVC emitting lights. A wall charging station 111 may be provided for periodically recharging the power source 109. The disinfection robot 100 further includes a processor system 113 for executing the robot-based activities discussed herein. A collar 115 may be used to enable physical and electrical separation of the light tower 107 from the main body of the robot 101. Necessary or desirable peripheral systems such as sensors, LIDAR sensors, cameras, motion tracking sensors, computer memory, latches, switches, antennas, communications facilities and so on are also included in the disinfection robot 100 but are omitted from the figure for clarity.
Turning to
This is an example of asymmetric robot design, with lights placed asymmetrically around the robot's central axis. As in
In a further aspect, ranging sensors (3D cameras/3D LIDARs) are located on the top of the tower, facing downwards on the sides. This configuration of sensors and the robot provides a complete view of 270 Degree (front, side with lamps and rear) in the vicinity of the robot. With such a detailed 3D view of its immediate surroundings, the robot can navigate with its lamps very close (e.g., 5-10 cm) from the surfaces to be disinfected. The combined effect of optimum lamp placement and optimum navigation can be seen in the plot 500 of
As can be seen, when the tower is placed at the edge of the robot (0 cm from robot edge, trace 501), there is a 5 fold, 500% increase (from 50 mJ/cm2 to 250 mJ/cm2) in UVC energy delivery, when the robot navigates at 20 cm from the surface compared to 30 cm to the surface.
It was noted above that a modular design is provided in an embodiment, wherein the UVC tower can be removed from the base for easy transport. With this modularity, the robot and tower can, for example, be transported without needing special high clearance vehicles. An example of this feature is shown in
In this embodiment, the tower 607 is electrically couplable with the robot base 601 (see also 101 of
This modular design allows different configurations of the UVC tower to be placed on the base depending upon the intended application and site complexities.
Disinfection robots generally operate in areas with high infection risk. While the robot performs its tasks of disinfecting the surfaces in its environment, the bio-contaminants may stick to the wheels of the robot and be transported to other areas. The foregoing placement of additional lamps places a low power UVC light source at a close proximity to the wheels, fenders and bottom surface of the robot, to constantly disinfect the area and prevent cross contamination between sites.
Most surfaces that need to be disinfected are in the hand height level for humans. However, there are places, especially in hospital environments, and operating rooms where objects such as overhead lamps, etc. can hang from the ceiling or otherwise be placed out of range. In these cases, referring to
Similar to the self-disinfecting embodiment of
Moreover, in accordance with a further embodiment, permanent placement of UVC reflective mirrors in certain places in a room may enable UVC light to reach places through reflection that are not reachable by direct line-of-sight UVC illumination from the robot. For example, the space behind cabinets, under tables or beds, on top of tall fixtures and so on may be out of line-of-sight range for a robot.
The hand-held self-contained disinfection unit 1300 can be mounted on the host robot 1200 as shown in
A human operator holding the handle 1315 may use the hand-held self-contained disinfection unit 1300 to manually shine UVC light on required surfaces, and may receive guidance by audio (via speaker 1317) or visual means as to where to apply disinfection (which spatial location) and for how long. With respect to visual guidance, the hand-held self-contained disinfection unit 1300 may include a visual indicator such as a screen or panel. Alternatively or additionally, a virtual reality (VR) or augmented reality (AR) headset may provide direct spatial visual guidance based on 3D spatial data from a prior executed automatic disinfection run by the robot.
It will be appreciated that various systems and processes have been disclosed herein. However, in view of the many possible embodiments to which the principles of the present disclosure may be applied, it should be recognized that the embodiments described herein with respect to the drawing figures are meant to be illustrative only and should not be taken as limiting the scope of the claims. Therefore, the techniques as described herein contemplate all such embodiments as may come within the scope of the following claims and equivalents thereof.
