EP4698327A1

EP4698327A1 - Autonomous mobile spraying apparatus

Info

Publication number: EP4698327A1
Application number: EP24719565.4A
Authority: EP
Inventors: Tobias Benighaus; Sven Roloff
Original assignee: Sika Technology AG
Current assignee: Sika Technology AG
Priority date: 2023-04-20
Filing date: 2024-04-19
Publication date: 2026-02-25
Also published as: WO2024218291A1

Abstract

The invention is directed to an autonomous mobile apparatus (100) for applying a liquid product to a horizontal surface by spraying comprising: - A mobile base (101) unit comprising a drive assembly, - A spraying assembly (102) comprising at least one applicator configured for applying the liquid product to the horizontal surface by spraying, and - A control unit (103) operable to control the movement of the mobile base unit (101) and the spraying assembly (102) for controlled application of the liquid product to the horizontal surface.

Description

AUTONOMOUS MOBILE SPRAYING APPARATUS

Technical field

The invention relates to autonomous or robotic devices and particularly to devices that are configured for autonomous application of liquid products to horizontal surfaces, such as floors of structures, by spraying.

Background of the invention

Application of liquid floor products, such as primers, coatings, or adhesives, to floor surfaces is a tedious task requiring manual application, for example using a notched trowel, a roller, or a squeegee, by specialized team of workers. The application work typically includes mixing of the base materials, pouring a correct volume of the mixture to the floor surface, spreading of the material to obtain a desired layer thickness, and ensuring appropriate drying and/or chemical curing of the wet layer. Some liquid products can also be applied by spraying but the spray applicator must still be manually manipulated to apply the liquid product to the target surface.

Such manual application processes are inefficient and prone to multiple errors despite the expertise of the workforce performing the tasks. For example, application of the liquid flooring products to obtain a coating with constant thickness is challenging, the amounts of materials may not be correctly measured, and manual application typically results in splashes of material onto the walls, which are difficult to remove.

Furthermore, the lack of work force in general but specifically in the construction industry has become visible in the past years and will become much more severe in the coming decade. The construction industry will, therefore, have to finalize more job sites with less people.

Robotic systems have been used for years, particularly for cleaning and painting applications, especially in automotive industry. Conventional automated painting systems in an automobile factory are immovable robots that are bolted to the floor of the factory, wherein the parts to be painted are moved via an assembly line. Furthermore, US 2019/0069745 A1 discloses a floor treatment system comprising a mobile floor cleaning apparatus and a docking station. The floor cleaning apparatus contains at least one liquid container and a liquid conduit for providing liquid to the container. The apparatus can be self-propelling and self-steering or it can be guided manually by the user as a ride-on or walk-behind apparatus. The liquid is applied to a floor surface using a cleaning unit having at least one roller-shaped or plate-shaped cleaning tool that is drivable in rotation.

US 2018/0093289 A1 discloses an automated mobile robot for painting of vertical surfaces. The robot comprises a wheeled base, a paint sprayer, a pump, a vision system, a GPS navigation system, and a computer controller. The mobile robot further comprises a local position and navigation system comprising series of beacons and markers for indication positions of windows and other objects that should not be painted. The disclosed mobile robot has been designed for painting of vertical walls and is as such not suitable for application of liquid materials to horizontal surfaces.

Consequently, the automated systems of prior art designed for application of liquid products do not resolve the issues as discussed above. They are also generally less suitable for application of liquid products to horizonal surfaces by spraying.

There is thus a need for a new type of device that that can be used for automatic application of liquid products to horizontal surfaces, particularly to floor surfaces, with little or no human intervention or assistance.

Brief description of figures

Figure 1 shows an illustrative drawing of an exemplary autonomous mobile apparatus.

Figure 2 is a flowchart of an exemplary process for applying a liquid product on a horizontal surface performed using an autonomous mobile apparatus

Figures 3a and 3b show examples of using a fixed or an optimized grid size in a route planning step for a horizontal area of a workspace without any fixed obstacles. Figures 4a and 4b show examples of using a fixed or an optimized grid size in a route planning step for a horizontal area of a workspace with a fixed obstacle.

Summary of the invention

It is an object of the present invention to provide an autonomous mobile apparatus for application of liquid products to horizontal surfaces, particularly to floors of structures, such as buildings, for example homes, offices, industrial buildings, garages, or basements, by spraying. Particularly, the autonomous mobile apparatus should be able to perform the application of the liquid product with little or no human intervention or assistance. The use of the apparatus should, therefore, result in significant improvements terms of efficiency and application quality.

Surprisingly, it has been found out that the object can be achieved with the features of claim 1.

Specifically, according to the invention, an autonomous mobile apparatus for applying a liquid product to a horizontal surface by spraying is proposed, the apparatus comprising:

- A mobile base unit comprising a drive assembly,

- A spraying assembly comprising at least one applicator configured for applying the liquid product to the horizontal surface by spraying, and

- A control unit operable to control the movement of the mobile base unit and the spraying assembly for controlled application of the liquid product to the horizontal surface.

As it turned out, the inventive autonomous mobile apparatus is especially suitable for applying liquid products, especially flooring products, to horizontal surfaces with little or no human assistance. The use of the autonomous mobile apparatus results in significant improvements in terms of installation costs and application quality.

Suitable liquid materials to be applied with autonomous mobile apparatus include, for example, primers, adhesives, technical coatings, floor sealers, and maintenance products. It has turned out that adhesives used for bonding of elastic floor coverings, such as polyvinylchloride (PVC), luxury vinyl tile (LVT), and carpet tiles, are especially suitable for being applied with the autonomous mobile apparatus of the present invention. The exemplary liquid products typically contain at least basic polymer or resin, for example at least one of acrylic, silane-functional, polyurethane, or isocyanate-functional polyurethane polymer, or an epoxide resin. Suitable liquid products include particularly one- and multiple-component reactive and non-reactive compositions.

The mobile base unit of the apparatus preferably comprises a drive assembly that allows the apparatus to move across the horizontal surface to be coated with the liquid product. The drive assembly can comprise wheels and at least one drive motor, such as an electric motor, although other types of drive assemblies, such as caterpillar treads or tracks, can also be used.

The spraying assembly, which is preferably supported on the mobile based unit, comprises one or more applicators that are configured for applying the liquid product to the horizontal surface by spraying. Preferably, the at least one applicator is configured to generate a spray of the liquid product from one or more nozzles, preferably from low pressure nozzles or airless nozzles.

The applicators(s) can be stationary or movable, for example with an actuator, especially while being supported at an end of a robotic arm. The thickness of the layer of the applied liquid product can be adjusted by controlling the flow rate of the liquid product though the applicator(s) and/or by controlling the speed at which the apparatus moves across the horizontal surface to be coated with the liquid product. Furthermore, the spraying width, i.e., the width of the layer of the liquid material applied when the apparatus is traversing a straight path, can preferably be controlled, for example, by adjusting the orientation and/or position of the one or more applicators, preferably nozzles.

The liquid product can be contained in one or more containers, which is/are preferably mounted within or on the mobile base unit, especially supported on the mobile base unit, particularly during application of the liquid product. It may be preferred that the container(s) are removably attached to the autonomous mobile apparatus, especially to the mobile base unit. The container(s) can be re-fillable or disposable cartridge(s), pail(s), or containers that are attached to the mobile base unit before the apparatus has been activated to execute a coating mission. Such containers can be removed after completion of the coating mission or when being replaced with new ones during the execution of the coating mission.

The control unit of the apparatus is responsible for conducting various tasks including planning of a queue of actions that are necessary to accomplish a coating mission defined by the user. Particularly, the control using is responsible for operating the autonomous mobile apparatus to execute the queue of actions including activating the spraying assembly for controlled spraying of the liquid product and causing the drive assembly to move the apparatus across the horizontal surface. The control unit may further be configured to communicate and receive instructions from a user, for example through user interface incorporated into the apparatus, for example into the mobile based unit, or from a remote device, such as a smart phone, tablet, laptop, or a remote control device.

The autonomous capabilities of the mobile apparatus are generally achieved by using advanced technologies including various sensors, such as mapping sensors and cameras, which provide data for the control unit using positioning, route planning, and obstacle avoidance technologies to provide functions enabling the autonomous operation of the mobile apparatus, such as localization, mapping, route and application planning, and autonomous navigation functions. For example, the obstacle avoidance function can be based on use of one or more cameras and/or mapping sensors, such as LiDAR sensors, that provide real-time data to the control unit that uses machine vision techniques to detect and avoid any fixed or moving obstacles that are present in the planned application route.

The autonomous mobile apparatus can furthermore be equipped with various sensors to provide real-time information about changes in properties of the liquid product and/or the application environment. It may, for example, be advantageous to measure the temperature and/or viscosity of the liquid product contained in the one or more containers or in a supply line connecting the container(s) with the applicators(s) of the spraying assembly. The information about the temperature and/or viscosity of the liquid product can, for example, be used for adjusting the pressure of the liquid product in the supply line and/or the moving speed of the apparatus to enable improved control and quality of the application process. Furthermore, it can be advantageous to measure the moisture content of the surrounding air and/the temperature of the horizontal surface since these can influence the curing speed and open time of the liquid product. Especially for one- and two-component reactive liquid products, the information about changing environmental conditions can be advantageously considered during route and application planning and execution of the coating mission.

Further aspects are described below and are subject of the further independent claims. Particularly preferred embodiments are outlined throughout the description and the dependent claims.

Detailed description of the invention

A first aspect of the present invention is directed to an autonomous mobile apparatus for applying a liquid product to a horizontal surface by spraying is proposed, the autonomous mobile apparatus comprising:

- A mobile base unit comprising a drive assembly,

The term “autonomous” is understood to mean in the context of the present disclosure that mobile apparatus is self-propelling and self-steering, i.e. , the apparatus is configured as a robot. The use of such robot enables autonomous application of the liquid product to a horizontal surface with little or no human involvement between the start and end of the coating mission. Furthermore, the term “horizontal surface” is understood to mean a surface that is substantially horizontal, i.e., that the surface is flat and contains a slope with respect to the horizontal plane of less than 30°, for example 15° or less.

Figure 1 shows an illustrative drawing of an exemplary autonomous mobile apparatus. As shown in Figure 1 , the autonomous mobile apparatus (100) may include a mobile base unit (101) comprising a drive assembly, a spraying assembly (102) comprising at least one applicator, a control unit (103), a mapping and navigation system (104) including a mapping sensor, a camera (105), one or more containers (106) for the liquid product, a user interface (107), communication means (108), and a power supply (109). In some embodiments, the autonomous mobile apparatus may be in data communication with an external control device (110), such as a smartphone, laptop, a tablet, or a remote control device, via the communication means (108).

The control unit (103) may contain a computing device that is operable to execute a stored program, i.e., software instructions, to control the operation of the components of the autonomous mobile apparatus, particularly the drive and spray assemblies, and to perform high level functions, for example, autonomous location, mapping, route and application planning, navigation, and obstacle avoidance functions, which are required for enabling the autonomous operation of the apparatus. The data required for executing the high level functions can be obtained from various sensors, for example mapping sensors and cameras. The computing device may include at least one processor or microprocessor, such as a CPU GPU, DSP, FPGA, or ASIC, that can execute the operations or program codes stored in a computer readable medium. The control unit may (103) further comprise a volatile memory such as random access memory (RAM) for dynamic data processing and program storage, a static or non-volatile memory such a ROM/Flash memory for either or both of maintaining an operating system and low-level hardware support code, and for long-term data storage.

The control unit (103) may further be configured to communicate and receive instructions from user, for example through user interface incorporated into the mobile apparatus, for example into the mobile base unit, or from an external device control (109), such as a smart phone, tablet, a laptop, or a remote control device. The external control device (109) can contain a software and wireless communication unit operable to communicate with the control unit (103), particularly through the communication means (108), and to issue commands to the control unit (103) to control the autonomous mobile apparatus (100).

The autonomous mobile apparatus is preferably configured for visualizing the workspace and determining appropriate movement pattern and operation of the spraying assembly for controlled application of the liquid product to the horizontal surface by spraying.

According to one or more embodiments, the autonomous mobile apparatus comprises a mapping and navigation system (104) including a mapping sensor configured to provide data for the control unit (103) to perform a simultaneous localization and mapping function. The mapping sensor (104) is particularly configured to determine the dimensions and shape of the working space and the dimensions of the area that is planned to be coated with the liquid product. The term “workspace” refers in the context of the present disclosure to a three-dimensional space, such as a part of a building, containing the horizontal surface.

Generally, the simultaneous localization and mapping (SLAM) is performed to provide information about the surface to be coated with the liquid product and position of items and fixed obstacles in the workspace and the position of the autonomous mobile apparatus in relation to these. The information obtained from SLAM is then used for defining paths for the autonomous mobile apparatus, i.e. , the route plan, and the application activities, for example, the flow rate of the liquid product the velocity of the apparatus when the liquid product is dispensed to the horizontal surface, i.e., the application plan. The route plan can include paths, where liquid product is applied and paths without application of liquid product, including start and stop points of the application process.

According to one or more embodiments, the mapping sensor (104) includes one or more of a 2D LiDAR scanner, 3D LiDAR scanner, ultrasound scanner, time-of-flight scanner, monocular camera, binocular camera, or a depth camera, particularly one or more of a 2D LiDAR scanner, 3D LiDAR scanner, or a depth camera, especially at least one 2D LiDAR scanner and/or at least one 3D LiDAR scanner.

The mapping sensor can further be configured to provide data for the control unit (103) to enable measuring of a gradient change across the horizontal surface to be coated with the liquid product. The information of the gradient change can be used in defining the route and/or application plan to ensure that sufficient amount of the liquid product is applied for leveling out the gradients.

According to one or more embodiments, the autonomous mobile apparatus further comprises at least one camera (105) to provide visual data for the control unit to identify uneven parts of the horizontal surface and/or to detect and avoid fixed or moving obstacles, such as human workers and/or other autonomous mobile apparatuses, that may obstruct the path of the mobile apparatus. The identification of uneven parts, such as bumps or ridges, and fixed or moving obstacles is based on analysis of the visual data provided by the camera(s) (105) by using machine vision/image processing techniques. The visual data from the camera(s) (105) can also be provided to the control unit (103), in addition to data from the mapping sensor (104) and used in performing the SLAM function.

The term “machine vision/image processing technique” refers to a technology based on use of cameras and artificial intelligence (Al) algorithms to identify, detect, and verify images to create a defined output. Typically, the data generated by the machine vision technology, i.e., the data generated by an algorithm on a computing device, is not deterministically replicable.

The control unit (103) may further be configured to automatically adjust the application of the liquid product in response to identified uneven parts of the horizontal surface to ensure a leveled-out surface finish. The instructions to level out uneven parts of the surface may be included in the coating mission.

According to one or more embodiments, the autonomous mobile apparatus is configured to avoid obstacles having a height greater than 15 mm, preferably greater than 10 mm, more preferably greater than 5 mm, in its path while moving across the horizontal surface and/or configured to pass over obstacles having a height of up to 15 mm, preferably up to 10 mm, more preferably up to 5 mm while moving across the horizontal surface.

According to one or more embodiments, the mapping and navigation system (104) further comprises inertial measurement unit (IMU) and/or rotary encoders (odometry). The IMU unit can be an assembly comprising inertial sensors including tri-axial accelerometers, triaxial gyroscopes and at least dual axial magnetic sensors. Tri-axial accelerometers measure the three dimensional acceleration with respect to a body frame. These measured accelerations can then be used to evaluate the position of the autonomous mobile apparatus.

The information obtained from IMU and/or rotary encoders is preferably communicated to the control unit, in addition to the information obtained from the mapping sensor and/or camera(s) (105) and used in performing the localization function. According to one or more embodiments, the driving assembly comprises wheels or caterpillar treads, or tracks, preferable wheels, and at least one drive motor, preferably an electronic motor. It may further be advantageous to have a drive motor for each wheel to improve fine control of the speed, direction, and turning radius of the autonomous mobile apparatus. The wheels and drive motors may be configured to enable a full turn of 90° to enable rotation on spot or sideways movement.

The spraying assembly (102) comprising at least one applicator is preferably supported on the mobile base unit, wherein the at least one application is preferably configured to generate a spray of the liquid product from one or more nozzles.

The spraying assembly (102) may be removably attached to the autonomous mobile apparatus, preferably to the mobile base unit (101), especially using form lock fixing.

The at least one applicator may thus contain one or more nozzles, particularly low pressure nozzles or airless nozzles. For example, the applicator may contain a single nozzle or be arranged as a spray head assembly with two or more nozzles. Airless nozzles break up fluid into small droplets without the use of compressed air. In an airless nozzle, fluid is pumped under high pressure through a spray tip. The material flow rate is determined by the tip size of the nozzle and pressure of the fluid. The use of airless nozzle(s) may generally be preferred since they enable more control over the fan width than conventional nozzles because the liquid is forced through the nozzle opening (spray tip) without being atomized by air.

It may be preferable that the dimensions and/or alignment and/or position of the nozzle(s) is/are adjusted such that the spraying width is at least 35 %, particularly at least 50 %, especially at least 75 % of the width of the mobile base unit (101 ). It may further be preferable that the spraying width is at least 100 %, particularly at least 110 % of the width of the mobile base unit (101). The term “width” of the mobile base unit refers here to the distance between two vertical planes parallel to the longitudinal median plane of the mobile base and touching both sides of the body of the mobile base unit (101).

It may also be preferable that the one or more nozzles are configured to be orientable and/or to be movable such that the spraying width can be adjusted during the application of the liquid product. Such configuration may be preferred to enable effective operation of the mobile application apparatus, especially in workspaces that contain a number of fixed obstacles and/or corners.

The autonomous mobile apparatus preferably further comprises at least one container (106) for containing the liquid product to be applied. Particularly, the autonomous mobile apparatus may further contain a supply line to deliver the liquid product from the at least one container (106) to the applicator(s). The at least one container (106) is preferably mounted within or on the mobile base unit (101), especially supported on the mobile base unit (101), particularly removable attached to the mobile base unit (101). The at least one container (106) can be a disposable package or a refillable reservoir or a pail. A single container can further be divided into several compartments/sections comprising, for example, components of a multi-component liquid product.

According to one or more embodiments, the at least one container (106) comprises a container wall and a container interior for containing the liquid product. The container wall can be composed of any suitable material, such as plastic, metal, organic, or organic- plastic composite material, especially carton and/or plastic material.

The autonomous mobile apparatus may further comprise a pump operable to draw the liquid product from the container(s) and to deliver it to the applicator(s) through a supply line. Alternatively, the pump may be operable to create an air pressure inside the containers(s) to deliver the liquid product to the applicator(s) through the supply line.

It may also be preferred that the autonomous mobile apparatus further includes a mixer arranged into the container(s) or between the applicator(s) and the container(s). According to one or more embodiments, the apparatus comprises first and second containers for containing a first and a second component of the liquid product and a mixer configured to mix the first and second components with each other before the liquid product is delivered to the applicator(s) through the supply line.

The amount of the liquid product in the at least one container (106) before start of the coating mission is preferably considered while preparing the application plan such that the mobile apparatus does not run out of the liquid product during application process. However, it may be preferred that the autonomous mobile apparatus further comprises a liquid product level detection system configured to monitor a level of the liquid product in the container(s) (106), preferably by using one or more of an ultrasonic sensor, float, infrared monitor, hydrostatic device, or a load cell. The use of such level detection system enables more accurate preparation of the application plan and detection of leakages in the container(s).

The spraying assembly may further comprise a sensor for measuring temperature and/or pressure of the liquid product in the supply line. The measurements from the temperature and/or pressure sensors can be used for determining the viscosity of the liquid product in the supply line.

Preferably, the spraying assembly further comprises at least one sensor for measuring the flow rate of liquid product, for example in the applicator(s) and/or in the supply line. The measured data from the flow rate sensor is preferably provided to the control unit to enable controlled application of the liquid product to the horizontal surface.

Furthermore, the mobile autonomous apparatus may contain a sensor for measuring the thickness of the layer of the applied liquid product and/or a sensor for measuring the distance of the at least one applicator from the horizontal surface to which the liquid product is being applied.

In some embodiments, it may be useful that the autonomous mobile apparatus further comprises at least one sensor for measuring temperature and/or moisture content of the surrounding air and/or temperature of the horizontal surface to which the liquid product is to be applied.

Especially for one- and two-component reactive liquid products, the moisture content and/or temperature of air and temperature of the horizontal surface can significantly influence the curing speed and open time of the layer of applied liquid product. Therefore, measured data about moisture content of air and temperature of the horizontal surface can be advantageously used for determining the route and application plans or for adjusting the application parameters, such as the flow rate of the liquid product and/or the moving speed of the apparatus in real-time.

According to one or more embodiments, the autonomous mobile apparatus is configured to automatically adjust at least one process parameter in response to measured changes of temperature and/or viscosity and/or pressure of the liquid product in the supply line and/or of temperature and/or moisture content of the surrounding air and/or or temperature of the horizontal surface, wherein the at least one process parameter is selected from flow rate of the liquid product though the applicator(s), moving speed of the mobile apparatus, and distance of the applicator(s) from the horizontal surface.

It may also be advantageous that the applicators have been configured to be movable in at least one direction, for example, to enable adjusting the distance of the applicator(s) from the horizontal surface during application of the liquid product. According to one or more embodiments, the autonomous mobile apparatus further comprises at least one actuator, such as a robotic arm, which is preferably supported on the mobile base unit, wherein the at least one applicator and/or the mapping sensor is/are supported at an end of the at least one robotic arm.

The at least one actuator can comprise a sensor configured to measure the precise position of a free end of the actuator, preferably of the robotic arm. The actuator is preferably configured to extend and retract the applicator(s) and/or mapping sensor during moving of the mobile base unit and application of the liquid product.

The autonomous mobile apparatus may further comprise a sensor configured to identify a machine readable code, preferably a bar code or a QR code. The machine readable code may, for example, contain information about the liquid product and/or about the coating mission.

Suitable sensor to identify a machine readable code, such as a QR code, may include a camera, preferably a digital camera, and a decoding software, such as a QR code reader software. Alternatively, a remote device, such as a digital camera-equipped smart phone including a QR code reader may be used to retrieve the information, which is then sent to the control unit (103) of the autonomous mobile apparatus, for example, using wireless communication means. The machine readable code may be present, for example, on an outer surface of the at least one container, particularly a disposable container, which is attached to the mobile base unit before start of the coating mission.

The control unit (103) may further be configured to enable an operator to manually control the autonomous mobile apparatus. The manual control may enable the operator to suspend or re-start a coating mission, to define start and/or end point in a route plan, or to manually control the movement and/or spraying process of the apparatus, for example, the flow rate and/or pressure of the liquid product. Manual override of the autonomous functions may be needed, for example, in case of device malfunction and/or rapidly changing environmental conditions. The manual control may be realized though the user interface (107) and/or by using an external control device (109), such as a smart phone, tablet, laptop, or a remote control device that is capable of providing instructions to the control unit (103) via wireless communication means.

The autonomous mobile apparatus may further comprise communication means (108), preferably wireless communication means, enabling to transmit user inputs wirelessly to the apparatus via wireless protocol, such as Bluetooth or Wi-Fi and/or a user interface (107) for interacting with controlling the operation of the apparatus. The user interface (107) can include a screen and/or a touch panel.

Particularly, the autonomous mobile apparatus further comprise a power supply (109), preferably one or more rechargeable or replaceable batteries to power the apparatus, particularly the drive assembly and/or the spraying assembly and/or the pump. The total capacity of the batteries is preferably selected such that a coating mission involving applying one layer of the liquid product to a horizontal surface having an area of at least 150 m², preferably at least 200 m², can be conducted without re-charging the batteries. In one or more embodiments, the power supply (109) comprises one or more 18 volts standard batteries.

Another aspect of the present invention is a method for applying a liquid product on a horizontal surface comprising steps of: i) Providing an autonomous mobile apparatus according to the present invention, ii) Providing a coating mission to the autonomous mobile apparatus, and iii) Activating the autonomous mobile apparatus for completing the coating mission.

Generally, some steps of the method could be implemented as a plurality of software instructions/commands being executed by a computer using any suitable operating system. In one or more embodiments, the liquid product is a building product, preferably selected from primers, adhesives, coatings, floor sealers, and maintenance products, more preferably from primers, adhesives, coatings, and floor sealers.

In one or more further embodiments, the liquid product has a viscosity of 0.1 to 200 Pa s, preferably 1 to 100 Pa s, more preferably 1 to 60 Pa s measured at temperature of 23 °C according to ISO 2884:2 standard, preferably measured at 20 revolutions per minute using a Brookfield DV-1 viscometer with a spindle No. 6 (RV).

Particularly, the liquid product may comprise an aqueous dispersion of at least one polymer P.

It may be preferable that the at least one polymer P is selected from of acrylic polymers and copolymers, styrene acrylic copolymers, styrene butadiene copolymers, polyurethane polymers, and ethylene vinyl acetate or acrylate copolymers.

In one exemplary embodiment, the liquid product is an adhesive, preferably a water- or a solvent-based adhesive.

The term “water-based adhesive” designates in the present disclosure adhesives, which have been formulated as an aqueous dispersion, an aqueous emulsion, or as an aqueous colloidal suspension. The term “aqueous dispersion” or “aqueous emulsion” refers to dispersions or emulsions containing water as the main continuous (carrier) phase. Typically, a water-based adhesive comprises surfactants to stabilize the hydrophobic polymer particles and to prevent these from coagulating with each other.

The term “solvent-based adhesive” designates in the present disclosure adhesives comprising polymers that are substantially completely dissolved in the organic solvent(s). Typically, solvent-based adhesive comprises at least 20 wt.-%, preferably at least 30 wt.- %, more preferably at least 40 wt.-%, of organic solvent(s). The term “organic solvent” refers in the present disclosure to organic substances that are liquid at a temperature of 25 °C, are able to dissolve another substance at least partially, and have a standard boiling point of not more than 225°C, preferably not more than 200 °C. The term “standard boiling point” refers in the present disclosure to boiling point measured at a pressure of 1 bar. The standard boiling point of a substance or composition can be determined, for example, by using an ebulliometer.

The coating mission provided in step II) of the method may include at least the following user determined parameters/settings:

- instructions on whether the entire horizontal area mapped by the apparatus should be coated with the liquid product or only one or more sub-sections and definitions for such a sub-section(s),

- number of superimposed layers of the liquid product to be applied during the coating mission,

- target coating height,

- instructions on whether any observed gradients should be corrected and to what extent,

- instructions on whether any observed surface irregularities, such as bumps or ridges, should be corrected and to what extent, and

- type of the coating material including open time, full curing time, and number of components.

According to one or more embodiments, the method for applying a liquid product comprises further steps of positioning the autonomous mobile apparatus in a workspace comprising the horizontal surface to be coated with liquid product and performing simultaneous localization and mapping of the workspace.

Further steps of the method may include defining a route plan and an application plan for executing the coating mission. Both of these further steps are preferably conducted after the apparatus has been provided with the coating mission and after the simultaneous mapping and localization step has been completed.

The route plan may define a desired trajectory for the autonomous mobile apparatus during application of the liquid product to the horizontal surface. The term “trajectory” is understood as data representing a sequence of positions that can also be presented as paths. The route plan may include paths, where the liquid product is applied and paths without application of liquid product. Generally, defining a route plan includes determining paths that the autonomous mobile apparatus should follow in order to apply the liquid product to the desired portion of the horizontal surface to execute the coating mission. Especially, the route plan is defined using boustrophedon cell decomposition (BCD) method.

The application plan may comprise information about the amount of the liquid product dispensed using the applicator(s) and optionally the spraying width as the apparatus is traversing across the horizontal surface to obtain a desired coating thickness and/or to level out gradients and/or correcting surface irregularities. The amount of the dispensed liquid product can be adjusted by controlling the flow rate of the liquid product through the applicator(s) and/or by controlling the moving speed of the apparatus. Furthermore, the spraying width can be controlled, for example, by adjusting the orientation and/or position of the one or more applicators, preferably one or more nozzles.

The activities conducted for defining the route plan and application plan may be conducted by the control unit of the autonomous mobile apparatus executing instructions of a computer software.

After the application and route plan have been defined, the apparatus starts to apply the liquid product to the horizontal surface. During the application step, the apparatus moves according to the instructions of the route plan and uses the mapping sensor and/or cameras and/or any other devices, such as I MU and/or rotary encoders, to provide data for the control unit to conduct localization and autonomous navigation functions. The autonomous navigation may be based on a control algorithm (PID, fuzzy, etc.) that aims to minimize the deviations between the planned route and the position of the apparatus. The application step is preferably conducted autonomously with little or no need for human (manual) intervention.

During the application step, the control unit of the apparatus can also use real-time data from the mapping sensor and/or cameras to detect and avoid fixed or moving obstacles, particularly those that were not identified during the initial simultaneous localization and mapping step and/or to detect any uneven or non-level portions of the horizontal surface to adjust in real-time the flow rate of the liquid product through the applicator(s), moving speed of the apparatus, and/or distance of the applicator(s) from the horizontal surface to ensure that the coated surface is even and level. In other words, the route plan and/or application plan may be adjusted in real-time during the application step based on the information received though the mapping sensors and/or camera(s) of the autonomous mobile apparatus.

The method for applying a liquid product may comprise a further step of charging the liquid product and/or the battery of the autonomous mobile apparatus. Charging the liquid product may include steps of:

- providing at least one container containing the liquid product and attaching the at least one container to the mobile base and/or

- filing the at least one container attached to the mobile base with the liquid product.

The at least one container can be a disposable package or a refillable reservoir or a pail. The at least one container can further be divided into several compartments/sections comprising, for example, different components of a multi-component liquid product. The step of charging of the liquid product and/or the battery can be conducted at any time before the apparatus is activated for executing the coating mission or after the application process has been suspended, for example, to recharge the container(s) with the liquid product and/or to recharge the battery of the apparatus.

The method for applying a liquid product can also include a further step of scanning a machine readable code, preferably a bar code or a QR code, and communicating the data to the control unit of the autonomous mobile apparatus.

The machine readable code may be scanned using a camera of the autonomous mobile apparatus or a remote device, such as a digital camera-equipped smart phone including a QR code reader, may be used to retrieve the information, which is then sent to the control unit of the autonomous mobile apparatus, for example, using wireless communication means.

The machine readable code may be present on an outer surface of the at least one container and the code can be read before attaching the container(s) to the mobile base unit.

Figure 2 is a flowchart of an exemplary process for applying a liquid product on a horizontal surface performed using an autonomous mobile apparatus as described above. The exemplary method begins by transporting the autonomous mobile apparatus to a construction site and positioning the apparatus to a workspace containing the horizontal surface to be coated with the liquid product. The apparatus can be positioned by personnel or it may autonomously move itself to a desired location. The workspace may be a room of a building, for example of a home, office, an industrial building, or a basement or garage space.

The next step of the exemplary process comprises defining a coating mission and communicating it to the mobile apparatus.

Defining the coating mission typically includes selecting one or more of the following parameters/settings for the application process:

- instructions on whether the entire horizontal area included in the digital map should be coated with the liquid product or only one or more sub-sections and definitions for such a sub-section(s),

- target coating height,

The coating mission can be communicated to the apparatus though user interface incorporated into the apparatus or by using a remote device, such as a smart phone, tablet, laptop, or a remote control device, which is connected to the control unit of the apparatus via wireless communication means. Generally, the coating mission can be defined and communicated to the autonomous mobile apparatus before, during, or after the apparatus has been positioned in the workspace.

The process further includes a mapping step to determine boundaries of the working space, such as walls, stairs, and doorways, dimensions the horizontal surface area to be coated with the liquid product, and to map any fixed obstacles, such as pillars, located in the workspace. Additionally, gradients and surface irregularities, such as bumps or ridges, may be mapped. The information obtained during the mapping step may be presented in a digital map of the workspace, which is stored to a memory of the control unit and used in the subsequent route and application planning steps.

The mapping step is preferably conducted autonomously without any human intervention or assistance. During the mapping step, the apparatus may move autonomously within the area of the workspace. In one alternative embodiment, the method comprises a further step for providing the autonomous mobile apparatus with structural data of the workspace. The structural data, if available, may for example be used to complement the data obtained during the mapping step.

After the mapping step, the route and application plans are defined based on the instructions of the coating mission and the information of the digital map of the workspace. The route plan includes pre-defined paths on the horizontal surface that the apparatus should follow to complete the coating mission, including start and stop positions of the application process. It may be preferred that the user defines only the stop position of the application process whereas the start position is defined by the control unit of the autonomous mobile apparatus executing instructions of a computer software. The paths may be defined such that only a sub-section of the horizontal surface or the entire area of the horizontal surface becomes covered with the liquid product and that any obstacles identified during the initial mapping step are effectively avoided. It may furthermore be preferred that the pre-defined paths of the route plan do not intersect to avoid damaging of the already laid layers of the liquid product. Particularly, the paths may be optimized such that the time required for completing the coating mission is minimized and/or coverage of the applied coating, i.e., the area of the workspace that becomes coated with the liquid product, is maximized whereas the area that cannot be coated, for example, to avoid fouling of structures that are not to be coated with the liquid material, is minimized.

Furthermore, the paths may be defined such that applied layers of the liquid material become partially overlapped. It may further be preferable that the width of the overlapping area, i.e., the width of an edge portion of one layer of the liquid material overlapped with another layer of liquid material, is at least 2.5 %, particularly 2.5 - 20 %, preferably 5 - 15 %, more preferably 5 - 10 % of the spraying width, i.e., of the width of the layer of liquid material. It may further be preferable that the paths are defined such that the minimum distance between a layer of liquid material and any vertical structure, such as a wall, is at least 2.5 cm, preferably at least 5 cm, particularly 5 - 25 cm, especially 5 - 15 cm, to avoid fouling of structures that are not to be coated with the liquid material.

In a first embodiment, the route planning step includes:

- dividing the horizontal surface area presented in a digital map of the workspace into identically sized cells, preferably having a shape of a square,

- defining a target area of said horizontal surface, which should be coated with the liquid product,

- dividing said target area into a whole number of equally sized grids having a size larger than the cells and preferably having a shape of a square, and

- defining the paths of the route plan such that the each of the grids becomes coated with the applied liquid product.

Preferably, the digital map is obtained from a previously conducted mapping step or simultaneous localization and mapping step. The shape and size of the grids is preferably selected such that each grid is composed of a whole number of cells.

In these embodiments, the size of each grid corresponds to the area of the horizontal surface that becomes coated with the liquid product after the autonomous mobile apparatus has traversed along a straight path defined by a row/column of consecutive grids for a distance of one single grid while simultaneously applying the liquid product.

Generally, the target area may include the free area of the horizonal surface of the workspace that is not covered with any fixed obstacles. However, it may also be preferred that one or more parts of the free area, for example, near the boundaries of the working space, such as walls, and/or near the fixed obstacles, is left out of the target area to avoid fouling of structures that are not intended to be coated with the liquid product and/or to enable removing the autonomous mobile robot from the workspace after completing the coating mission without damaging the applied coating of the liquid product. The sizes of such “safety areas” that are intentionally not included in the target area depend on the dimensions of the autonomous mobile apparatus, particularly the width of the mobile base unit, and whether the spraying width can be adjusted based on the selected size of the grids.

In a second embodiment, the route planning step includes

- defining safety areas, for example, near the boundaries of the working space and/or near the fixed obstacles, if present, that are not to be coated with the liquid product,

- defining a target area of said horizontal surface, which should be coated with the liquid product and which does not include the safety areas,

- defining the paths of the route plan such that the each of the grids becomes coated with the liquid product.

Th size of the grids may depend on the dimensions of the autonomous mobile apparatus, particularly the width of the mobile base unit, and whether the spraying width can be adjusted based on the selected size of the grids. For example, the size of each grid may be in the range of 10 - 150 cm², particularly 25 - 100 cm², especially 35 - 75 cm².

In practice, the requirement of using a whole number of the grids typically results the total area of the grids being significantly smaller than the target area. Consequently, the area of the horizontal surface that does not become coated the liquid product is larger than the sum of the safety required areas, which increases the amount manual work after the completion of the coating mission using the autonomous mobile apparatus.

It may therefore be preferred that the size of the grids is selected such that the proportion of the total area of the grids of the target area becomes maximized. Such optimization of the size of the grids typically requires that the spraying width can be adjusted, for example, by changing the type of the applicator(s), such as the size of the spray tip of the nozzle(s), and/or by adjusting the orientation and/or position of the applicators, particularly of one or more nozzles.

In a third embodiment, the route planning step includes - dividing the horizontal surface area presented in a digital map of the workspace into identically sized cells, preferably having a shape of a square,

- defining safety areas, for example, near the boundaries of the working space and/or near the fixed obstacles, if present, that are not intended to be coated with the liquid product,

- selecting a size of grids that maximizes the total area covered by the grids when the target area is divided into a whole number of equally sized grids having a size larger than the cells and preferably having a shape of a square,

- dividing said target area into a whole number of the grids having the selected size and shape, and

- defining the paths of the route plan such that each grids becomes coated with the liquid product.

Examples of using a fixed or an optimized grid size in a route planning step for a horizontal area of a workspace using a cell size of 10 cm² are shown in Figures 3 and 4.

In the examples of Figure 3a and 3b, the total free horizontal area is 1550 cm² and standard safety areas having a width of at least 10 cm are left near all four boundaries (walls) of an exemplary workspace having a shape of a square. In the first example of Figure 3a, a fixed grid size of 50 cm² is selected and the adjusted safety areas near the right and bottom boundary must then be set to have a width of 40 cm and 50 cm, respectively. This results in a target area of 1125 cm², which is only 73 % of the available total free horizontal area. In the second example of Figure 3b, a grid size of 40 cm² is selected, which results in much larger target area of 1344 cm² and a coverage of the applied liquid product of 87 %.

In the examples of Figures 4a and 4b, the total free horizontal area of the workspace is 1656 cm² and the workspace is limited by six walls and it also includes a rectangular fixed obstacle located in the middle of the workspace. Safety areas are left near the walls and also around the fixed obstacle. In the first example of Figure 4a, a fixed grid size of 50 cm² is selected and the safety areas near the boundaries and the fixed obstacle are then be set to have a width of 20 - 40 cm. This results in a target area of 1300 cm², which is only 79 % of the total available free horizontal area of the work space. In the second example of Figure 4b, an adjusted grid size of 40 cm² is selected, which results in much larger target area of 1440 cm² and a coverage of the applied liquid product of 87 %.

The application planning includes steps of defining the amount of the liquid product to be applied to the horizontal surface when the apparatus is moving across the horizontal surface following the paths defined in the route plan. Especially, the application planning may include defining the flow rate and optionally the spraying width of the liquid product dispensed through the applicator(s), preferably one or more nozzles, the moving speed of the apparatus, and the distance of the applicator(s) from the horizontal surface that are required to obtain a desired coating thickness and to level out any gradients and/or correcting surface irregularities, to complete the given coating mission.

The exemplary process further includes a step of charging the liquid product and/or the battery. Charging the liquid product may include attaching one or more containers containing the liquid product to the mobile base of the apparatus or filing one or more container attached to the mobile base with a liquid product.

In the application step, the liquid product is applied to the horizontal surface employing the autonomous mobile apparatus. Particularly, the apparatus moves autonomously on the horizontal surface following the instructions of the route and application plans using autonomous navigation functions. During the application step, the apparatus can also use real-time data obtained from sensors and/or cameras to detect and avoid fixed or moving obstacles, particularly those that were not recognized in the preceding mapping step. Such real-time data can further be used to detect uneven or non-level portions of the horizontal surface and to adjust the route and/or application plan to ensure that the coated surface is even and level.

In case the coating mission requires application of a further coating layer, the application step is repeated before ending of the process.

During the application process, the autonomous mobile apparatus may also provide information about its activities and status of the coating mission in real time. Such information may be provided through the user interface of the apparatus and/or through a remote device connected to the apparatus via the wireless communication means.

Claims

1 . An autonomous mobile apparatus (100) for applying a liquid product to a horizontal surface by spraying comprising:

- A mobile base unit (101) comprising a drive assembly,

- A spraying assembly (102) comprising at least one applicator configured for applying the liquid product to the horizontal surface by spraying, and

- A control unit (103) operable to control the movement of the mobile base unit (101) and the spraying assembly (102) for controlled application of the liquid product to the horizontal surface.

2. The autonomous mobile apparatus according to claim 1 further comprising a mapping and navigation system (104) including a mapping sensor configured to provide data for the control unit (103) to perform simultaneous localization and mapping function.

3. The autonomous mobile apparatus according to claim 2, wherein the mapping sensor includes one or more of 2D LiDAR scanner, 3D LiDAR scanner, ultrasound scanner, time-of-flight scanner, monocular camera, binocular camera, or a depth camera, preferably one or more of 2D LiDAR scanner, 3D LiDAR scanner, or depth camera.

4. The autonomous mobile apparatus according to any one of previous claims further comprising at least one camera (105) to provide visual data for the control unit (103) to identify uneven parts of the horizontal surface and/or to detect and avoid fixed or moving obstacles that may obstruct the path of the apparatus.

5. The autonomous mobile apparatus according to claim 4, wherein the control unit (103) is further configured to automatically adjust the application of the liquid product in response to identified uneven parts of the horizontal surface to ensure a leveled-out surface finish.

6. The autonomous mobile apparatus according to any one of claims 2-5, wherein the mapping and navigation system (104) further comprises inertial measurement unit (IMU) and/or rotary encoders.

7. The autonomous mobile apparatus according to any one of previous claims, wherein the at least one applicator is configured to generate a spray of the liquid product from one or more nozzles, preferably one or more airless nozzles.

8. The autonomous mobile apparatus according to any one of previous claims, wherein the spraying assembly (102) removably attached to the autonomous mobile apparatus, preferably to the mobile base unit (101), especially using form lock fixing.

9. The autonomous mobile apparatus according to any one of previous claims further comprising at least one container (106) for containing the liquid product to be applied and a supply line to deliver the liquid product from the at least one container (106) to the applicator(s), wherein the at least one container (106) is supported on the mobile base unit (101), preferably removably attached to the mobile base unit (101).

10. The autonomous mobile apparatus according to claim 9 further comprising a pump operable to draw the liquid product from the container(s) (106) and to deliver it to the applicator(s) through the supply line or a pump operable to generate an air pressure inside the contain er(s) (106) to deliver the liquid product to the applicator(s) through the supply line.

11. The autonomous mobile apparatus according to claim 9 or 10 being configured to automatically adjust at least one process parameter in response to measured changes of temperature and/or viscosity and/or pressure of the liquid product in the supply line and/or of temperature and/or moisture content of the surrounding air and/or or temperature of the horizontal surface, wherein the at least one process parameter is selected from flow rate of the liquid product though the applicator(s), moving speed of the mobile apparatus, and distance of the applicator(s) from the horizontal surface

12. The autonomous mobile apparatus according to any one of previous claims further comprising a sensor configured to identify a machine readable code, preferably a bar code or a QR code, wherein the machine readable code is preferably present on the outer surface of the at least one container (106).

13. The autonomous mobile apparatus according to any one of previous claims further comprising communication means (108) enabling to transmit user inputs wirelessly to the apparatus via wireless protocol.

14. The autonomous mobile apparatus according to any one of previous claims further comprising a power supply (109), preferably one or more rechargeable or replaceable batteries, to power the apparatus, particularly the drive assembly and/or the spraying assembly (102).

15. A method for applying a liquid product on a horizontal surface comprising steps of: i) Providing an autonomous mobile apparatus according to any one of previous claims, ii) Providing a coating mission to the apparatus, and iii) Activating the apparatus for completing the coating mission.

16. The method according to claim 15, wherein the liquid product is a building product, preferably selected from primers, adhesives, coatings, and floor sealers.

17. The method according to claim 15 or 16, wherein the liquid product has a viscosity of 0.1 to 200 Pa s, preferably 1 to 100 Pa s, measured at temperature of 23 °C according to ISO 2884:2 standard, preferably at 20 revolutions per minute using a Brookfield DV-1 viscometer with a spindle No. 6 (RV).

18. The method according to any one claims 15-17, wherein the liquid product comprises an aqueous dispersion of at least one polymer P.

19. The method according to any one of claims 15-18, wherein the at least one polymer P is selected from of acrylic polymers and copolymers, styrene acrylic copolymers, styrene butadiene copolymers, polyurethane polymers, and ethylene vinyl acetate or acrylate copolymers.

20. The method according to any one of claims 15-19, wherein the liquid product is an adhesive, preferably a water- or a solvent-based adhesive.

21 . The method according to any one of claims 15-20 further comprising of positioning the autonomous mobile apparatus in a workspace comprising the horizontal surface to be coated with liquid product and performing simultaneous localization and mapping of the workspace.

22. The method according to any one of claims 15-21 further comprising defining a route plan and an application plan for executing the coating mission.

23. The method according to claim 22, wherein the step of defining a route plan includes:

- dividing the horizontal surface area presented in a digital map of the workspace, preferably obtained from the mapping step, into identically sized cells, preferably having a shape of a square,

- defining a target area of said horizontal surface, which is intended to be coated with the liquid product,

- defining the paths of the route plan such that said grids become coated with the liquid product.

24. The method according to claim 22, wherein the step of defining a route plan includes:

- dividing the horizontal surface area presented in a digital map of the workspace, preferably obtained from the mapping step, into identically sized square shaped cells, preferably having a shape of a square,

- defining a target area of said horizontal surface, which is intended be coated with the liquid product and does not include the safety areas, - selecting a size of grids that maximizes the total area covered by the grids when the target area is divided into a whole number of equally sized grids having a size larger than the cells and preferably having a shape of a square,

- dividing said target area into a whole number of the grids having the selected size, and

25. The method according to any one of claims 15-24 comprising a further step of scanning a machine readable code, preferably a bar code or a QR code, and communicating the data to the control unit of the mobile autonomous apparatus.