WO2021156416A1

WO2021156416A1 - Robotic device and method of operating the same

Info

Publication number: WO2021156416A1
Application number: PCT/EP2021/052763
Authority: WO
Inventors: Celal Mohan OEGUEN; Sebastian Valouch
Original assignee: Trinamix Gmbh
Priority date: 2020-02-06
Filing date: 2021-02-05
Publication date: 2021-08-12

Abstract

A robotic device (110) is proposed, the robotic device (110) being configured for autonomously performing at least one task by using at least one actuator (116). The robotic device (110) is capable of locomotion. The robotic device (110) comprises at least one light source (132) and at least one optical sensor (134). The optical sensor (134) is configured for detecting light (136) emitted by the light source (132). The actuator (116) comprises at least one moving part (120) configured for performing a periodic movement. The robotic device (110) is configured for using the moving part (120) for modulating the light (136) emitted by the light source (132). Further, a method of operating a robotic device (110) for autonomously performing at least one task is disclosed.

Description

Robotic device and method of operating the same

Technical Field

The method invention generally relates to a robotic device for autonomously performing at least one task by using at least one actuator as well as to a method of operating a robotic device, the robotic device being configured for performing at least one task. The robotic device and the method specifically may be employed, for example, in various areas of daily life, such as in the field of robotic devices for household tasks. As an example, the robotic device and the method may be employed for cleaning, specifically vacuuming or wiping, for gardening, e.g. mowing, or the like. However, other applications are also possible.

Background art

A large number of robotic devices, such as robots or autonomous guided vehicles configured for performing household tasks, are known from prior art. The robots may be used, for example, for cleaning, e.g. vacuuming and wiping, mowing and surveillance. Without narrowing the scope, the invention will specifically be described with respect to household use.

Many robotic devices make use of one or more optical detectors comprising at least one light source and at least one optical sensor. Thus, as an example, distance measurements or other measurements are essential for robotic devices to navigate through environments or for robotic devices to generate information on the properties of an object, such as spectral properties. These optical detectors often are configured for measuring light reflected from at least one tar get. As an example, for distance measurements, the light intensity, the time delay or reflection profiles of light reflected from at least one object may be assessed.

US 2015/277440 A1 describes an automated mobile vehicle that includes one or more distance determining elements configured to detect the presence of objects and to cause the automated mobile vehicle to alter its path to avoid the object. For example, a distance determining element may be incorporated into one or more of the motors of the automated mobile vehicle and con figured to determine a distance to an object. Based on the determined distance, a path of the automated mobile vehicle may be altered.

US 2017/082486 A1 describes an optical detector, the optical detector comprising: at least one spatial light modulator being adapted to modify at least one property of a light beam in a spatial ly resolved fashion, having a matrix of pixels, each pixel being controllable to individually modify the at least one optical property of a portion of the light beam passing the pixel; at least one optical sensor adapted to detect the light beam after passing the matrix of pixels of the spatial light modulator and to generate at least one sensor signal; at least one modulator device adapted for periodically controlling at least two of the pixels with different modulation frequen cies; and at least one evaluation device adapted for performing a frequency analysis in order to determine signal components of the sensor signal for the modulation frequencies. US 2018/169863 A1 describes an autonomous robot comprising a robot body, a drive config ured to propel the robot, a sensor system disposed on the robot body, and a navigation control ler circuit in communication with the drive and the sensor system. The sensor system comprises at least one proximity sensor comprising a sensor body, and a first emitter, a second emitter and a receiver housed by the sensor body, wherein the receiver detects objects in a bounded detection volume of the receiver field of view aimed outward and downward beyond a periphery of the robot body. The receiver is disposed above and between the first and second emitters, the emitters having a twice-reshaped emission beams angled upward to intersect the receiver field of view at a fixed range of distances from the periphery of the robot body to define the bounded detection volume.

In optical measurements, however, specifically in field applications, various technical effects may lead to performance losses of the measurement. Thus, as an example, the light source may change over time, such as by drifting. Further, the optical sensor may be subject to noise effects, typically depending on the measurement frequency. Still further, sensor signals received by the optical sensor may be affected by ambient light.

One solution addressing these technical challenges is modulating the light source. Some light sources typically used for optical measurements, such as light emitting diodes or lasers, can be modulated in a simple fashion, such as by modulating their electric drive current. The modula tion of other light sources such as broad band radiators like incandescent lamps, however, is technically more challenging and, often, is only possible at low frequencies and with spectral shifts. For modulating the light, specifically in the latter case, various technical solutions are known. Thus, as an example, optical choppers or shutters may be used or other mechanical, micromechanical, optical, micro-optical or opto-mechanical setups. Optical choppers, for exam ple, may be used for calibration purposes, such as by dark signal measurements, for spectral measurements or for distance measurements.

Nevertheless, the above-mentioned external means for periodically modulating light imply some technical challenges. Thus, specifically, the implementation of choppers or shutters generally requires additional construction space. In robotic devices, however, construction space always is an issue. Further, the implementation of choppers or shutters generally requires additional assembly and additional parts and, therefore, increases the system costs. Still further, choppers or shutters generally are sensitive optical or optomechanical parts which are sensitive against shocks and contaminations which, specifically in household tasks, may be a constructive chal lenge. This sensitivity against shocks and contaminations may reduce the robustness of the mechanical setup and may increase maintenance efforts.

Problem to be solved

It is therefore desirable to provide a robotic device and a method of operating the same which are suited for optical measurements and which, at least partially, address the above-mentioned challenges of known devices and methods of similar kind. Specifically, a robotic device and a method of operating the same shall be proposed which allow for precise optical measurements using at least one light source and at least one optical sensor, by still avoiding the issue of a significant increase in assembly space, by avoiding a significant increase in system costs and by still providing a high robustness against mechanical shocks and contaminations.

Summary

This problem is addressed by a robotic device and a method of operating a robotic device, with the features of the independent claims. Advantageous embodiments which might be realized in an isolated fashion or in any arbitrary combinations are listed in the dependent claims.

As used in the following, the terms “have”, “comprise” or “include” or any arbitrary grammatical variations thereof are used in a non-exclusive way. Thus, these terms may both refer to a situa tion in which, besides the feature introduced by these terms, no further features are present in the entity described in this context and to a situation in which one or more further features are present. As an example, the expressions “A has B”, “A comprises B” and “A includes B” may both refer to a situation in which, besides B, no other element is present in A (i.e. a situation in which A solely and exclusively consists of B) and to a situation in which, besides B, one or more further elements are present in entity A, such as element C, elements C and D or even further elements.

Further, it shall be noted that the terms “at least one”, “one or more” or similar expressions indi cating that a feature or element may be present once or more than once typically will be used only once when introducing the respective feature or element. In the following, in most cases, when referring to the respective feature or element, the expressions “at least one” or “one or more” will not be repeated, notwithstanding the fact that the respective feature or element may be present once or more than once.

Further, as used in the following, the terms "preferably", "more preferably", "particularly", "more particularly", "specifically", "more specifically" or similar terms are used in conjunction with op tional features, without restricting alternative possibilities. Thus, features introduced by these terms are optional features and are not intended to restrict the scope of the claims in any way. The invention may, as the skilled person will recognize, be performed by using alternative fea tures. Similarly, features introduced by "in an embodiment of the invention" or similar expres sions are intended to be optional features, without any restriction regarding alternative embodi ments of the invention, without any restrictions regarding the scope of the invention and without any restriction regarding the possibility of combining the features introduced in such way with other optional or non-optional features of the invention.

In a first aspect of the invention, a robotic device is proposed, the robotic device being config ured for autonomously performing at least one task by using at least one actuator.

The term “robotic device” as used herein is a broad term and is to be given its ordinary and cus tomary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary device configured for performing at least one task autonomously, i.e. without human intervention or direct human controlling. Specifically, the robotic device may be configured for autonomously detecting properties of an environment and for autonomously adapting its own actions to these properties, in order to perform the at least one task. Thus, the robotic device may comprise at least one controller being programmed for performing the at least one task by controlling one or more actuators, the controller being programmed for taking into account one or more sensor signals when performing the task, the one or more sensor signals being indicative of the at least one property of the environment. As an example, the at least one task may be a household task. Other tasks, however, are feasible, as will be explained in further detail below. The robotic device specifically may be configured, such as by programming, for performing the at least one task in the absence of external assistance or instructions, such as for example without assis tance from a user or control by a user. Specifically, the robotic device may be configured to re act to specific situations independent from external input, by using pre-programmed routines, self-learning mechanisms or the like.

The term “task” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an action to be performed or a goal of our aim to be achieved. Specifically, the task may imply a manipulation of the at least one element, such as by exerting at least one force to the at least one element. Thus, the task specifically may comprise manipulating at least one element and/or changing at least one prop erty of the at least one element. The task may be or may comprise a single aim or may com prise a plurality of components, such as steps or aspects of the task. Thus, the task may imply achieving a goal or a bite performing a single step or by performing a plurality of steps.

The term “actuator” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an element, a device or a system which is configured for exerting at least one force and/or at least one action onto at least one element or object and/or which is configured for changing at least one property of the element or object. As an example, the actuator may be or may comprise at least one mechanical actua tor configured for exerting at least one mechanical action onto the element or object. In addition or as an alternative to at least one mechanical actuator, other types of actuators are also feasi ble, such as one or more of: an electrical actuator, an electromechanical actuator, an optical actuator, and optomechanical actuator. In case the at least one actuator comprises at least one mechanical actuator, the at least one mechanical actuator specifically may comprise at least one motor, such as at least one electrical motor. As will be outlined in further detail below, the at least one actuator specifically may be or may comprise at least one rotating actuator, such as a rotor. The robotic device specifically may comprise at least one energy storage device, such as at least one battery and/or at least one accumulator, allowing for the robotic device to perform the at least one task autonomously and without being permanently connected to an energy source. The at least one energy storage device specifically may be directly or indirectly coupled to the at least one actuator, for providing electrical energy to the at least one actuator.

The robotic device is capable of locomotion. The term “locomotion” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to the capability of moving in space, such as on the ground, in the air or in the water. For this purpose, the robotic device specifically may comprise at least one drive element, for one or more of moving, accelerating or decelerating the robotic device. Thus, the robotic device may comprise one or more of wheels, a Caterpillar drive, a propeller, a carriage or an other device capable of driving or moving the robotic device on the ground and/or in the air and/or in water. Specifically and without excluding further possibilities, the robotic device may be a ground robotic device, being capable of autonomously driving on the ground. As an exam ple, the robotic device may comprise at least one corpus and two or more wheels for moving the corpus on the ground. The at least one actuator may be implemented into the corpus and/or may be attached to the corpus.

The robotic device comprises at least one light source and at least one optical sensor, wherein the optical sensor is configured for detecting light emitted by the light source. The at least one light source and the at least one optical sensor specifically may form at least one optical detec tor.

The term “light” is a broad term and is to be given its ordinary and customary meaning to a per son of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to electromagnetic radiation in the wavelength range of 10 nm to 1 mm. Therein, the spectral range of 380 nm to 760 nm may be referred to as the visible spectral range, wherein the wavelength range of light having wavelengths below this visible spectral range may be referred to as the ultraviolet spectral range, and wherein the wavelength range of light having wavelengths above the visible spectral range may be referred to as infrared spectral range. Therein, the spectral range of 760 nm to 1.4 pm may be referred to as the near infrared (NIR) spectral range. The term “light source” is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to a device configured for emitting light. Specifically, the light source may comprise one or more of: an incandescent lamp, a light-emitting diode, a laser, an IR thermal source. The term “optical sensor”, similarly, is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning.

The term specifically may refer, without limitation, to an arbitrary device which is capable of qualitatively and/or quantitatively detecting light in the above-mentioned sensor. Thus, the de vice specifically may comprise at least one sensitive element which is capable of changing at least one measurable property depending on an illumination with light. The optical sensor spe cifically may comprise one or more of: a photodiode, a phototransistor, a photoresistor, a semi conductor sensor, a photomultiplier, a photocell, a phototube, a thermal detector, a pyroelectric detector, a thermopile, a bolometer, a Golay cell, photochemical sensor. The optical sensor may be a single optical sensor having a single, uniform sensitive element or sensitive surface, or may be an optical sensor having a plurality of sensitive elements, such as a pixelated sensor, e.g. a CCD or CMOS device.

As outlined above, the optical sensor is configured for detecting light emitted by the light source. This configuration may have different aspects or components. Thus, firstly, the optical sensor should be sensitive in at least one spectral range emitted by the at least one light source, unless wavelength-changing properties of indirection of the light with at least one object are used. In the latter case, the optical sensor should be sensitive in a spectral range after wavelength trans formation by the object. As a further aspect, a geometrical configuration or optical path configu ration of an optical setup comprising the optical sensor and the light source should be arranged such that the light emitted by the light source, directly or indirectly, may reach the optical sen sor. Thus, specifically, the optical sensor should be arranged such that at least one sensitive surface of the optical sensor is accessible for the light.

The actuator comprises at least one moving part configured for performing a periodic move ment. Thus, as an example, the moving part may be a rotor driven by at least one driving ele ment of the actuator, such as a motor, specifically an electric motor. As an example, the rotor may comprise one or more rotating arms which are suspended in a rotatable or pivotable way about at least one axle. Additionally, or alternatively, the at least one moving part configured for performing the periodic movement may also be or may comprise at least one lever arm or pen dulum suspended by at least one pivot. Other options are feasible. The periodic movement may be a periodic movement with a single and constant frequency. As an example, the moving part may perform one or more of a circular movement at a constant angular frequency, an oscillating movement having a constant oscillation frequency or the like. Alternatively, however, the period ic movement may also be a periodic movement having a frequency spectrum having a plurality of frequencies and/or may have a frequency changing with time.

The at least one moving part specifically may be configured for being used for performing the at least one task. Thus, as an example, the at least one moving part may be configured for per forming at least one household task and/or for contributing to the performing of the at least one household task. As an example, and as will be outlined in further detail below, the at least one moving part specifically may be part of the cleaning mechanism, such as by providing at least one brush, e.g. a rotating brush. These rotating brushes, as an example, are generally known in cleaning robots, such as vacuum cleaning robots.

The robotic device is configured for using the moving part, e.g. in addition to using the moving part for performing the at least one task, for modulating the light emitted by the light source. Therein, the term “modulating” also is a broad term and is to be given its ordinary and custom ary meaning to a person of ordinary skill in the art and is not limited to a special or customized meaning. The term specifically may refer, without limitation, to the process of changing, specifi cally periodically changing, at least one property of the light, specifically one or both of an inten- sity or a phase of the light. The modulation may be a full modulation from a maximum value to zero, or may be a partial modulation, from a maximum value to an intermediate value greater than zero.

Thus, generally, the moving part may be placed and configured such that, during the move ment, the moving part interacts with light originating from the light source in a varying way, such as depending on an orientation and/or position of the moving part. Since the moving part is ca pable of performing a periodic movement, and since the interaction with the light depends on the orientation and/or the position, light or a portion of the light received by the optical sensor may be modulated in one or more of the above-mentioned ways.

The light emitted by the light source may reach the at least one optical sensor in various ways. Thus, as an example, a direct light path between the light source and the optical sensor may exist. Additionally, or alternatively, the light emitted by the light source may be reflected by at least one object or surface external to the robotic device, such as a wall or an obstacle in a path of the robotic device and/or by an object to be analyzed by the robotic device. After reflection, the light may be directly or indirectly reach the optical sensor. Thus, the light path may also be folded by one or more reflections, with one or more reflective surfaces internal and/or external to the robotic device. Still further, and again additionally or alternatively, the light may reach at least one object and may be scattered or reflected elastically or inelastically, wherein an inelas tic scattering or reflection may imply a change of wavelength. In any of the named cases, the moving part may fully or partially be located in the at least one light path in between the light source and the optical sensor, such that a movement of the moving part may modulate the light received by the optical sensor.

As outlined above, the actuator specifically may be or may comprise at least one mechanical actuator. The task, thus, specifically may comprise performing at least one mechanical action by using the actuator. As outlined above, however, other tasks are also feasible. Generally, the task may be selected from the group consisting of: a household task; an industrial manufactur ing task; a logistics tasks, such as warehouse logistics, automated optical sorting tasks, such as plastic, food, recycling, minerals sorting; safety and security related tasks, such as fire inspec tion.

The robotic device specifically may comprise at least one controller for controlling the perform ing of the task and for controlling the operation of the light source and the optical sensor. The term “controller” as used herein is a broad term and is to be given its ordinary and customary meaning to a person of ordinary skill in the art and is not to be limited to a special or customized meaning. The term specifically may refer, without limitation, to an arbitrary electronic device configured for controlling one or more operations of the robotic device. The controller specifical ly may be programmable. Thus, the controller specifically may comprise at least one processor. The term “processor” as used herein is a broad term and is to be given its ordinary and custom ary meaning to a person of ordinary skill in the art and is not to be limited to a special or cus tomized meaning. The term specifically may refer, without limitation, to an arbitrary logic circuitry configured for performing basic operations of a computer or system, and/or, generally, to a de vice which is configured for performing calculations or logic operations. In particular, the pro cessor may be configured for processing basic instructions that drive the computer or system.

As an example, the processor may comprise at least one arithmetic logic unit (ALU), at least one floating-point unit (FPU), such as a math coprocessor or a numeric coprocessor, a plurality of registers, specifically registers configured for supplying operands to the ALU and storing re sults of operations, and a memory, such as an L1 and L2 cache memory. In particular, the pro cessor may be a multi-core processor. Specifically, the processor may be or may comprise a central processing unit (CPU). Additionally or alternatively, the processor may be or may com prise a microprocessor, thus specifically the processor’s elements may be contained in one sin gle integrated circuitry (IC) chip. Additionally or alternatively, the processor may be or may com prise one or more application-specific integrated circuits (ASICs) and/or one or more field- programmable gate arrays (FPGAs) or the like.

The processor specifically may be configured, such as by software programming, for performing and/or supporting the performing of the at least one task. In addition, the processor specifically may be configured, such as by software programming, for performing and/or supporting at least one optical measurement by using the at least one light source and the at least one optical sen sor.

Thus, generally, the robotic device specifically may be configured for performing at least one optical measurement by using the light source and the optical sensor. Thus, specifically by cor responding software programming, the controller and/or the processor may be configured for controlling the light source to emit light and/or may be configured for receiving and/or pro cessing one or more sensor signals received by the optical sensor. The robotic device specifi cally may be further configured for taking the periodic modulation of the light into account for the optical measurement. Taking into account the modulation may take place in various ways, as the skilled person in the field of optical measurements generally will appreciate. Thus, as an example, filter techniques may be used, in order to select measurement signals in a frequency range around the modulation frequency of the modulation and/or in order to disregard meas urement signals in a frequency range around the modulation frequency. As an example, back ground light and/or noise may fully or partially be eliminated or at least suppressed by using a bandpass-filter with the modulation frequency being located within a transmission range of the bandpass-filter, whereas measurement signals having other frequencies, including noise and background light, are suppressed. Additionally, or alternatively, specifically in case the modula tion frequency of the modulation is known and is available as a separate periodic signal such as a sinusoidal electrical signal, lock-in techniques may be used, as the skilled person will know. Thus, the periodic signal may be mixed with the measurement signal, and the mixed-signal may be filtered by using at least one low-pass filter. Other techniques taking into account the periodic modulation of the light for the optical measurement are generally known and may be used here. These techniques may comprise electronic techniques and/or may comprise optical techniques. The evaluation may fully or partially be performed by using electronic components and/or may fully or partially be performed by using software evaluation. The at least one optical measurement specifically may be selected from the group consisting of: an intensity measurement, specifically for measuring a light intensity; a distance measurement for measuring the distance between the robotic device and at least one object; a 3-D optical measurement; a position measurement; a spectral measurement for determining at least one spectral property of an object; an environmental measurement for optically determining at least one property of an environment of the robotic device; a motion detection, a proximity detection, a heat or temperature detection, a smoke detection, an occupancy detection, a concentration detection by means of transmission measurements according to Lambert-Beer law. One or more optical measurements may be performed by the robotic device. Thus, the robotic device may comprise a single optical detector or a plurality of optical detectors, each optical detector having at least one light source and at least one optical sensor, wherein, in case a plurality of optical detectors are provided, the optical detectors may be configured for performing the same optical measurement or for performing different types of optical measurements. Thus, as an example, one or more optical detectors may be provided for performing distance measurements and/or for detecting objects in the vicinity of the robotic device, and one or more optical detec tors may be provided for determining one or more optical properties of at least one object or sample, such as for performing at least one spectroscopic measurement. Various combinations are feasible.

The robotic device, as outlined above, may be configured for taking into account the periodic movement of the at least one moving part when performing the optical measurement. Specifi cally, the robotic device, as outlined above, may be configured for at least one of a frequency filtering of a signal received by the optical sensor and a lock-in measurement using the signal received by the optical sensor and a frequency of the periodic movement of the moving part. As outlined above, the filtering and/or the lock-in measurement may fully or partially be performed electronically and/or may fully or partially be performed by using software.

As outlined above, the moving part specifically may comprise at least one rotating part, such as a rotor. Additionally, or alternatively, other moving parts may be used, such as a pendulum and/or a pivotable part. Generally, the moving part specifically may be at least partially located in at least one light path of the light, such as in at least one light path of at least one light beam emitted by the light source and directly or indirectly being directed to the optical sensor. For possible embodiments of this at least one light path, reference may be made to the description given above. Thus, the light path may be or may comprise a straight light path and/or may be or may comprise at least one folded light path having one or more reflection points. Thus, as an example, the light emitted by the at least one light source may be directed towards at least one object and may be reflected and/or scattered elastically or inelastically by the at least one ob ject, wherein the reflected light directly or indirectly propagates towards the at least one optical sensor.

As outlined above, the at least one moving part may periodically interact with the light emitted by the light source, such that the light received by the optical sensor, due to this modulation, is periodically modulated in at least one measurable property, such as one or more of an ampli- tude or a phase. As an example, the moving part specifically may be configured for one or both of periodically interrupting the light or periodically deflecting the light. Specifically, the moving part may be configured for periodically deflecting, fully or partially, the light towards the optical sensor. Thus, for example, in a rotational movement and/or in a pendulum movement, the at least one moving part may have at least one reflective surface and/or at least one scattering surface, wherein, as an example, only in case the moving part is oriented and/or located in a specific way, the light reflected and/or scattered by the reflective or scattering surface fully or partially reaches the optical sensor.

Thus, generally, the moving part may comprise at least one reflective surface. The reflective surface, as an example, may be or may comprise a metallic surface and/or a reflective plastic surface.

The moving part may also be configured for periodically interrupting the light. Thus, as an ex ample, the at least one moving part may periodically block at least one light path of the light, thereby fully or partially preventing the light reaching the at least one optical sensor. The robotic device specifically may be configured for using signals of the optical sensor during periods of interruption for dark signal measurements. These dark signal measurements, as an example, may be indicative for background light or ambient light.

Specifically, the at least one moving part may comprise at least one light absorbing surface, specifically a blackened surface. Thus, as an example, the moving part may comprise at least one absorbing surface to block the light from the light source to fully or partially prevent this light reaching the optical sensor, specifically for periodically blocking the light.

The moving part specifically may comprise at least one rotating brush. Thus, as outlined above, the at least one task of the robotic device specifically may comprise at least one cleaning task, such as a brushing and/or vacuum cleaning task. The rotating brush specifically may, thus, be or may comprise at least one cleaning brush.

The optical setup of the robotic device, including the light source and the optical sensor, specifi cally may be configured such that a direct propagation of light from the light source to the optical sensor is prevented. In other words, the optical setup may be such that the light source is not directly visible from the location of the optical sensor. In case a plurality of optical detectors is provided in the robotic device, this setup may be given for one or more of the optical detectors. Preventing a direct illumination of the optical sensor-light source may specifically ensure that the light has to be reflected or scattered at least once before reaching the at least one optical sensor. Thereby, generally, a signal-to-noise ratio may be increased and/or a background signal may be reduced. Specifically, a direct light path between the light source and the optical sensor may be blocked by at least one blocking element of the robotic device. Thereby, the light emit ted by the light source, for reaching the optical sensor, has to be one or more of reflected, de flected or scattered. The robotic device specifically may be configured for performing at least one calibration process by using light emitted by the light source and modulated by the moving part. Thus, as an exam ple, the light source may be used for calibrating the at least one optical sensor. The optical sen sor, generally, besides detecting light emitted by the light source, may also be used for other purposes, such as for detecting ambient light. By calibrating the optical sensor using the light source, a quantitative detection of the ambient light may be performed. The calibration process may be performed by using the modulated light. The calibration process specifically may com prise one or more of: a background calibration; a distance measurement calibration; a drift cali bration, specifically a light source drift calibration and/or a sensor drift calibration of the optical sensor; a distance calibration; a spectral calibration; an intensity calibration; a dark noise cali bration.

In a further aspect of the present invention, a method of operating a robotic device is disclosed. Therein, the robotic device is configured for autonomously performing at least one task by using at least one actuator, the actuator comprising at least one moving part. The robotic device is capable of locomotion and comprises at least one light source and at least one optical sensor. The method comprises the following method steps. The method steps specifically may be per formed in the given order. A different order, however, is also possible, including the option of performing one or more of the method steps fully or partially simultaneously. Further, one or more of the method steps may be performed in a repeated fashion. The method may comprise additional steps which are not listed.

The method comprises the following steps: i. emitting light by using the light source; ii. modulating the light emitted by the light source by having the moving part perform a peri odic movement; and iii. receiving the modulated light by using the optical sensor.

The method specifically may comprise using the robotic device of the present invention, such as according to any one of the embodiments described above and/or according to any one of the embodiments described in further detail below. Thus, for possible definitions and options of the method, reference may be made to the description of the robotic device.

The robotic device and the method as proposed herein provide for a large number of ad vantages over known devices and methods of similar kind. Thus, specifically, the above- mentioned technical challenges of known optical measurements can be addressed, specifically in the harsh environments of robotic devices. Specifically, light may be modulated for all sorts of optical measurements in a simple, efficient and robust fashion. The at least one actuator and specifically its at least one moving part may be used in dual use, both for performing the task of the robotic device and for performing the light modulation. Thereby, modulated light signals may be provided in robotic devices in a simple and efficient way, such as for dark signal measure ments like dark noise, dark current, dark voltage and the like. Additionally, or alternatively, spec- tral measurements may be performed and/or distance measurements or measurements of structures in an environment of the robotic device.

Thus, specifically, one or more periodically moving parts may be used for modulating the light. As an example, a vacuum cleaning robot may be used. Therein, typically, rotating brushes gen erate a periodic movement. One or more optical detectors may be used, each optical detector having at least one light source and the at least one optical sensor. These optical detectors may, as an example, be implemented for intensity measurements and/or distance measure ments, such as for detecting obstacles and/or for drop detection, also known as cliff detectors. Additionally, or alternatively, any other type of optical detector may be implemented, such as at least one spectral detector for spectral identification or classification of materials, e.g. for floor materials and/or for objects on the floor. The at least one optical detector or at least a part thereof, such as the at least one light source and/or the at least one optical sensor, may be po sitioned behind the brushes in such a way that the optical sensor detects modulated light at a frequency given by the rotational frequency of the brush or a multiple thereof, depending on the number of brush arms of the brush. By electronic and/or software filtering, signal parts originat ing from ambient light, which typically is not modulated or modulated at a different frequency, may be removed. Additionally, or alternatively, noise may be removed or at least suppressed. Thus, as an example, flicker noise, also known as 1/f noise, which typically is frequency de pendent, maybe suppressed by using filtering techniques, making use of the fact that the signal of interest is modulated at the known frequency. Thus, generally, the brushes may serve as optical choppers and the modulated light may be used for suppressing noise effects.

In addition, or as an alternative to using the brush or the other moving part of the robotic device as a chopper, reflective properties of the moving part may be used for modulation. Thus, as an example, if the material of the brush of the cleaning robot has an adequate reflection spectrum, the light source and the at least one optical sensor, such as the spectral sensor, may be posi tioned behind the brush in such a way that the reflected light from brush to the optical sensor can be used to recalibrate the optical sensor. Thus, generally in this or in other embodiments, making use of the fact that the light source and the moving part may have known spectral emis sion properties or reflection properties, respectively, the modulated signal generated by the at least one optical sensor, such as a spectral sensor, may be calibrated by the robotic device. Again, additionally or alternatively, an intensity measurement sensor may use the light reflected from the moving part, such as the brush, in order to recalibrate itself against light source or sen sor drifts.

Further, again additionally or alternatively, the fact may be used that, typically, the geometrical setup of the robotic device is well known. Thus, as an example, a distance between the light source and the moving part and/or a distance between the moving part and the optical sensor is typically well known. As an example, thus, for example in time-of-flight measurements, a modu lated signal generated by the light reflected by the moving part may be used for distance cali bration. As an example, at least one distance measurement detector comprising at least one light source and at least one optical sensor may be placed in the vicinity and/or behind one or more of the moving parts, such as one or more brushes, in such a way, that a signal generated by the light reflected by the moving part is used for distance calibration. As an example, when a distance measurement detector is positioned behind brushes, the distance between the brushes and the detector may be used to recalibrate the detector.

Again, additionally or alternatively, the at least one optical detector may be positioned such that the at least one optical sensor of the optical detector is periodically darkened by the at least one moving part. As an example, the optical detector or a part thereof, such as the at least one opti cal sensor of the optical detector, may be positioned behind the brushes of the robotic device.

By periodically darkening the illumination of the optical sensor, the optical sensor may be dark ened for dark noise measurements.

Generally, thus, the robotic device may be configured for using modulated light reflected by the at least one moving part for calibration purposes, such as for spectral calibration, intensity cali bration, drift calibration, distance calibration or dark noise calibration.

For periodically modulating the light reflected and/or deflected and/or transmitted by the moving part, at least one surface and/or at least one material of the moving part may be adapted corre spondingly. Thus, as an example, the moving part may comprise at least one absorbing sur face, such as a blackened surface, to block the light propagating from the light source to the optical sensor. Additionally, or alternatively, the moving part may comprise at least one reflect ing surface, such as a metallic reflective surface. Thereby, as outlined above, reflections of the light reaching the optical sensor may be used e.g. for recalibrating spectral information obtained with the optical sensor. Additionally, or alternatively, the moving part may comprise at least one reflective surface usable for calibration purposes. Thus, reflected light may also be used for dis tance calibration, as outlined above.

Thus, generally, a few modifications to existing systems may be necessary, in order to imple ment the possibility of improving optical measurements by using modulated light. Existing mov ing parts may be combined with one or more optical sensors and/or one or more light sources, in order to allow for optical measurements such as distance measurements, cliff detection, spectral measurements, intensity measurements, dark measurements or the like.

Summarizing and without excluding further possible embodiments, the following embodiments may be envisaged:

Embodiment 1 : A robotic device for autonomously performing at least one task by using at least one actuator, wherein the robotic device is capable of locomotion, wherein the robotic device comprises at least one light source and at least one optical sensor, wherein the optical sensor is configured for detecting light emitted by the light source, wherein the actuator comprises at least one moving part configured for performing a periodic movement, wherein the robotic device is configured for using the moving part for modulating the light emitted by the light source. Embodiment 2: The robotic device according to the preceding embodiment, wherein the actua tor is a mechanical actuator, wherein the task comprises at least one mechanical action by us ing the actuator.

Embodiment 3: The robotic device according to any one of the preceding embodiments, where in the task is selected from the group consisting of: a household task; an industrial manufactur ing task; a logistics tasks, such as warehouse logistics, automated optical sorting tasks, such as plastic, food, recycling, minerals sorting; safety and security related tasks, such as fire inspec tion.

Embodiment 4: The robotic device according to any one of the preceding embodiments, where in the robotic device comprises at least one controller for controlling the performing of the task and for controlling the operation of the light source and the optical sensor.

Embodiment 5: The robotic device according to any one of the preceding embodiments, where in the robotic device is configured for performing at least one optical measurement by using the light source and the optical sensor, wherein the robotic device is further configured for taking the periodic modulation of the light into account for the optical measurement.

Embodiment 6: The robotic device according to the preceding embodiment, wherein the optical measurement is selected from the group consisting of: an intensity measurement, specifically for measuring a light intensity; a distance measurement for measuring the distance between the robotic device and at least one object; a 3-D optical measurement; a position measurement; a spectral measurement for determining at least one spectral property of an object; an environ mental measurement for optically determining at least one property of an environment of the robotic device; a motion detection, a proximity detection, a heat or temperature detection, a smoke detection, an occupancy detection, a concentration detection by means of transmission measurements according to Lambert-Beer law.

Embodiment 7: The robotic device according to any one of the two preceding embodiments, wherein the robotic device is configured for at least one of a frequency filtering of a signal re ceived by the optical sensor and a lock-in measurement using the signal received by the optical sensor and a frequency of the periodic movement of the moving part.

Embodiment 8: The robotic device according to any one of the preceding embodiments, where in the moving part comprises a rotating part.

Embodiment 9: The robotic device according to any one of the preceding embodiments, where in the moving part is at least partially located in at least one light path of the light, specifically of at least one light beam emitted by the light source, and directly or indirectly being directed to the optical sensor. Embodiment 10: The robotic device according to any one of the preceding embodiments, wherein the moving part is configured for one or both of periodically interrupting the light, specif ically at least one light beam, or periodically deflecting the light, specifically at least one light beam.

Embodiment 11 : The robotic device according to the preceding embodiment, wherein the mov ing part is configured for periodically, fully or partially, deflecting the light, specifically as at least one light beam of the light, towards the optical sensor.

Embodiment 12: The robotic device according to any one of the two preceding embodiments, wherein the moving part comprises at least one reflective surface.

Embodiment 13: The robotic device according to any one of the three preceding embodiments, wherein the moving part is configured for periodically interrupting the light, such as at least one light beam of the light, wherein the robotic device is configured for using signals of the optical sensor during periods of interruption for dark signal measurements.

Embodiment 14: The robotic device according to any one of the preceding embodiments, wherein the moving part comprises a rotating brush.

Embodiment 15: The robotic device according to the preceding embodiment, wherein the task comprises at least one cleaning task, wherein the rotating brush is a cleaning brush.

Embodiment 16: The robotic device according to any one of the preceding embodiments, wherein the moving part comprises at least one light absorbing surface, specifically a blackened surface.

Embodiment 17: The robotic device according to any one of the preceding embodiments, wherein a direct light path between the light source and the optical sensor is blocked by at least one blocking element of the robotic device, such that the light emitted by the light source, for reaching the optical sensor, has to be one or more of reflected, deflected or scattered.

Embodiment 18: The robotic device according to any one of the preceding embodiments, wherein the robotic device is configured for performing at least one calibration process by using light emitted by the light source and modulated by the moving part.

Embodiment 19: The robotic device according to the preceding embodiment, wherein the cali bration process comprises one or more of: a background calibration; a distance measurement calibration; a drift calibration, specifically a light source drift calibration and/or a sensor drift cali bration of the optical sensor; a distance calibration; a spectral calibration; an intensity calibra tion; a dark noise calibration. Embodiment 20: A method of operating a robotic device for autonomously performing at least one task by using at least one actuator comprising at least one moving part, the robotic device being capable of locomotion, the robotic device comprising at least one light source and at least one optical sensor, the method comprising: i. emitting light by using the light source; ii. modulating the light emitted by the light source by having the moving part perform a peri odic movement; and iii. receiving the modulated light by using the optical sensor.

Embodiment 21 : The method according to the preceding embodiment, the method comprising using the robotic device according to any one of the preceding embodiments referring to a ro botic device.

Short description of the Figures

Further optional features and embodiments will be disclosed in more detail in the subsequent description of embodiments, preferably in conjunction with the dependent claims. Therein, the respective optional features may be realized in an isolated fashion as well as in any arbitrary feasible combination, as the skilled person will realize. The scope of the invention is not restrict ed by the preferred embodiments. The embodiments are schematically depicted in the Figures. Therein, identical reference numbers in these Figures refer to identical or functionally compara ble elements.

In the Figures:

Figure 1 shows a first embodiment of a robotic device in a partial cross-sectional view; and Figure 2 shows a second embodiment of a robotic device in partial bottom view.

Detailed description of the embodiments

In Figure 1 a partial cross-sectional view of the robotic device 110 is shown. The robotic device 110 is configured for autonomously performing at least one task. As shown in Figure 1 , the task specifically may be or may comprise a household task, such as a cleaning task. As an example, the robotic device 110 may be a vacuum cleaning robot.

The robotic device 110 is configured for locomotion and may comprise at least one movement actuator or drive, such as at least one wheel 112 for moving the robotic device 110 in one or more directions on the ground 114. The configuration of the drive, however, may be adapted to the actual conditions under which the robotic device 110 is employed and may vary accordingly. For performing the at least one task, the robotic device 110 comprises at least one actuator 116. The actuator, as an example, may comprise, specifically for performing a cleaning task, at least one rotating brush 118. Generally, however, the actuator 116 comprises at least one mov ing part 120. In the embodiment shown in Figure 1 , as an example, the moving part 120 com prises one or more brushes 122 as a part of the rotating brush 118. It shall be noted, however, that other types of moving parts 120 are also feasible. Generally, the at least one moving part 120 is configured for performing at least one periodic movement. As an example, the periodic movement may comprise a circular movement. In the embodiment shown in Figure 1, the brush 122 is configured for rotating about an axle 124 driven by a corresponding drive 126, such as a motor, e.g. an electric motor. The robotic device 110 may comprise an internal energy storage device 128, such as a battery and/or an accumulator, specifically a rechargeable energy stor age device 128, which may provide sufficient electric energy for operating the drive 126.

The robotic device 110 further comprises at least one optical detector 130. The optical detector 130 comprises at least one light source 132 and at least one optical sensor 134. The light source 132 is configured for emitting light 136, and the optical sensor 134 is configured for de tecting the light 136. As will be outlined in further detail below, the light 136 may propagate di rectly or indirectly from the light source 132 to the optical sensor 134. As an example, the light 136 may be reflected once or repeatedly.

The robotic device 110 may further comprise at least one controller 138, such as at least one controller having at least one processor. The controller 138 may be or may comprise a single device or may comprise a plurality of interacting devices. The controller 138 may be configured for controlling the operation of the robotic device 110, such as for controlling the performing of the at least one task. For this purpose, the controller 138, as an example, may control the oper ation of the at least one drive 126. Further, the controller 138 may be configured for performing at least one optical measurement by using the at least one optical detector 130, as will be out lined in further detail below. For this purpose, as an example, the controller 138 may directly or indirectly control the operation of the at least one light source 132 and/or may directly or indi rectly read out one or more sensor signals provided by the at least one optical sensor 134.

The robotic device 110 may additionally comprise at least one signal processing device 140, such as at least one signal processing device 140 having at least one filter 142. In the exempla ry and simplified embodiment shown in Figure 1, for illustration purposes, a bandpass filter is shown. The filter 142 specifically may be adapted to at least one driving frequency of the drive 126, as symbolically shown in Figure 1. Thus, as an example, the bandpass filter may have an adjustable transmission frequency transmission range, which may be adapted to the rotational frequency of the drive 126 and/or to a multiple thereof, such as the rotational frequency multi plied by the number of moving parts 120 in the actuator 116, e.g. the number of brushes 122. It shall further be noted that the at least one signal processing device 140 may be more complex than shown in the simplified embodiment of Figure 1. Thus, as an example, a signal processing setup for use in a lock-in device may also be present, as the skilled person will appreciate. It shall further be noted that the at least one signal processing device 140 may also fully or partial- ly be implemented into the controller 138, such as by implementing one or more of the signal processing components by software components.

The components as shown above may fully or partially be included into at least one housing 144 of the robotic device 110. Thus, as an example, electronic components may fully or partially be encased by the housing 144, for protecting these components in harsh environmental condi tions.

The robotic device 110, in this embodiment or in other embodiments, is configured for using the at least one moving part 120 modulating the light 136 emitted by the light source 132. Thus, as can be seen in Figure 1, the light 132 interacts with the moving part 120 at least once, before directly or indirectly, fully or partially, being detected by the optical sensor 134. The interaction may be or may comprise, as an example, one or more of: a reflection, a deflection, a scattering, a transmission, a change in spectral properties, a partial or full absorption, an interruption. Other types of interaction are also feasible.

The robotic device 110 as shown in Figure 1 or similar devices in accordance with the present invention may be used for implementing a method in accordance with the invention. Thus, the method may comprise emitting the light 136 by using the light source 132. The method further may comprise modulating the light 136 by having the moving part 120 perform a periodic movement, such as by having a periodic interaction with the light 136. Thereby, the light 136 is periodically modulated. The method may further comprise receiving the light 136 by using the optical sensor 134.

In Figure 2, a further embodiment of a robotic device 110 is shown in a partial bottom view. The setup of the robotic device 110 is similar to the embodiment shown in Figure 1 , so for most components, reference may be made to the description of Figure 1 above.

The bottom view in Figure 2 shows that the embodiment of the robotic device 110, and again, may comprise at least one wheel 112, in order to allow for locomotion of the robotic device 110. Further wheels 112 may be provided. The robotic device 110, further, comprises, as an exam ple, two actuators 116 comprising rotating brushes 118, wherein, as an example, each rotating brush 118 may comprise three moving parts 120 and body as brushes 122.

Further, in the embodiment of Figure 2, three optical detectors 130 are shown, wherein, as an example, each of the optical detectors 130 comprises at least one light source 132 and at least one optical sensor 134, in close vicinity. The light source 132 and the optical sensor 134 may, thus, also fully or partially be integrated into one part.

Out of the three optical detectors 130, one optical detector 130 is located right in front of the wheel 112 and is unaffected by the rotation of the rotating brush 118. Thus, as an example, this optical detector 130 may be based on a modulated light. Alternatively, the light emitted by the light source 132 of this front optical detector 130 may be modulated by other means. The two remaining optical detectors 130, however, are located in close vicinity to the rotating brushes 118, such as underneath the brushes 122, as shown in Figure 2. Thus, the light emitted by the light sources 132 of these optical detectors 130 may be modulated before reaching the optical sensor 134 of the respective optical detector 130. This embodiment shows that, in case a plural ity of optical detectors 130 is provided, at least one of the optical detectors 130 is embodied such that the light is modulated by the actuator 116, notwithstanding the option that one or more other optical detectors 130 may operate without modulation.

The optical detectors 130 in the embodiments shown in Figures 1 and 2 may be used for vari ous purposes. Thus, as an example, one or more of the optical detectors 130 may be used for cliff detection or drop detection, such as for avoiding the robotic device 110 falling down a stair case. Additionally or alternatively, one or more of the optical detectors 130 may detect spectral properties of the ground 114, such as reflective properties, e.g. for adapting the cleaning pro cess to the material of the ground 114 and/or for the purpose of orientation in space. Other em bodiments are feasible, as outlined above. Thus, the one or more optical detectors 130 may be implemented, as an example, for one or more of: an intensity measurement, specifically for measuring a light intensity; a distance measurement for measuring the distance between the robotic device 110 and at least one object, such as a horizontal distance measurement and/or a drop detection; a 3-D optical measurement; a position measurement; a spectral measurement for determining at least one spectral property of an object; an environmental measurement for optically determining at least one property of an environment of the robotic device; a motion detection, a proximity detection, a heat or temperature detection, a smoke detection, an occu pancy detection, a concentration detection by means of transmission measurements according to Lambert-Beer law. Other embodiments of the optical measurement are feasible. The light 136 emitted by the at least one light source 132 may be modulated in one or more optical properties, such as one or more of intensity, phase or spectral composition. The modulation, as outlined above, may take place, as an example, by one or more of types of interaction with the light 136. The modulated light may be used for various purposes. Thus, as an example, dark current measurements may be performed, by periodically blocking the light 136. Additionally, or alterna tively, as an example, a noise reduction or noise suppression may take place, such as by using the filtering techniques and/or the lock-in techniques explained above. Additionally, or alterna tively, calibration measurements may be performed, as outlined above. Generally, modulated light may be used for improving a signal-to-noise ratio and/or for improving the quality of the measurement results. Further, modulated light may also be used for improving spectral meas urements and/or for material detection. Various other uses of modulated light are generally fea sible. List of reference numbers

110 robotic device

112 wheel

114 ground

116 actuator

118 rotating brush

120 moving part

122 brush

124 axle

126 drive

128 energy storage device

130 optical detector

132 light source

134 optical sensor

136 light

138 controller

140 signal processing device

142 filter

144 housing

Claims

1. A robotic device (110) for autonomously performing at least one task by using at least one actuator (116), wherein the robotic device (110) is capable of locomotion, wherein the ro botic device (110) comprises at least one light source (132) and at least one optical sen sor (134), wherein the optical sensor (134) is configured for detecting light (136) emitted by the light source (132), wherein the actuator (116) comprises at least one moving part (120) configured for performing a periodic movement, wherein the robotic device (110) is configured for using the moving part (120) for modulating the light (136) emitted by the light source (132), wherein the moving part (120) is configured for periodically interrupting the light (136), wherein the robotic device (110) is configured for using signals of the opti cal sensor (134) during periods of interruption for dark signal measurements.

2. The robotic device (110) according to the preceding claim, wherein the actuator (116) is a mechanical actuator (116), wherein the task comprises at least one mechanical action by using the actuator (116).

3. The robotic device (110) according to any one of the preceding claims, wherein the task is selected from the group consisting of: a household task; an industrial manufacturing task; a logistics tasks; an automated optical sorting task; a safety and/or security related task.

4. The robotic device (110) according to any one of the preceding claims, wherein the robotic device (110) comprises at least one controller (138) for controlling the performing of the task and for controlling the operation of the light source (132) and the optical sensor (134).

5. The robotic device (110) according to any one of the preceding claims, wherein the robotic device (110) is configured for performing at least one optical measurement by using the light source (132) and the optical sensor (134), wherein the robotic device (110) is further configured for taking the periodic modulation of the light (136) into account for the optical measurement.

6. The robotic device (110) according to the preceding claim, wherein the optical measure ment is selected from the group consisting of: an intensity measurement; a distance measurement for measuring the distance between the robotic device (110) and at least one object; a 3-D optical measurement; a position measurement; a spectral measurement for determining at least one spectral property of an object; an environmental measurement for optically determining at least one property of an environment of the robotic device (110); a motion detection; a proximity detection; a heat or temperature detection; a smoke detection; an occupancy detection; a concentration detection by means of transmission measurements according to Lambert-Beer law.

7. The robotic device (110) according to any one of the two preceding claims, wherein the robotic device (110) is configured for at least one of a frequency filtering of a signal re ceived by the optical sensor (134) and a lock-in measurement using the signal received by the optical sensor (134) and a frequency of the periodic movement of the moving part (120).

8. The robotic device (110) according to any one of the preceding claims, wherein the mov ing part (120) comprises a rotating part.

9. The robotic device (110) according to any one of the preceding claims, wherein the mov ing part (120) is at least partially located in at least one light path of the light (136) emitted by the light source (132) and directly or indirectly being directed to the optical sensor (134).

10. The robotic device (110) according to any one of the preceding claims, wherein the mov ing part (120) is configured for one or more of: periodically deflecting the light (136); peri odically deflecting the light (136) towards the optical sensor (134).

11. The robotic device (110) according to any one of the preceding claims, wherein the mov ing part (120) comprises a rotating brush (118).

12. The robotic device (110) according to any one of the preceding claims, wherein the robotic device (110) is configured for performing at least one calibration process by using light (136) emitted by the light source (132) and modulated by the moving part (120).

13. The robotic device (110) according to the preceding claim, wherein the calibration process comprises one or more of: a background calibration; a distance measurement calibration; a drift calibration; a distance calibration; a spectral calibration; an intensity calibration; a dark noise calibration.

14. A method of operating a robotic device (110) for autonomously performing at least one task by using at least one actuator (116) comprising at least one moving part (120), the robotic device (110) being capable of locomotion, the robotic device (110) comprising at least one light source (132) and at least one optical sensor (134), the method comprising: i. emitting light (136) by using the light source (132); ii. modulating the light (136) emitted by the light source (132) by having the moving part (120) perform a periodic movement; and iii. receiving the modulated light (136) by using the optical sensor (134).