Robotic floor cleaner

Abstract

A robotic vacuum cleaner comprises a body and a forward-facing camera 24 wherein the camera has a horizontal field of view of at least 160°. The horizontal view is preferably no more than 190° and th

Description

BACKGROUND Robotic floor cleaners often use several navigation systems to map and navigate their environment adequately. For example, a robotic floor cleaner may include both a vision system and a LiDAR system for navigation and object detection. Improvements in robotic floor cleaner navigation systems are desirable. SUMMARY The present disclosure relates to a robotic floor cleaner comprising a body and a forwardfacing camera coupled to the body, wherein the forward-facing camera has a horizontal field of view (FOV) of at least 160°. In this way, the robotic floor cleaner may be adapted to carry out both navigation and object detection using a single camera. For example, the wide horizontal FOV of the forward-facing camera may mean that the robotic floor cleaner is well suited to navigation, e.g., such a robotic floor cleaner may not be required to rotate to recognise its location. Further, the camera being forward-facing may mean that the camera is able to detect objects on the floor. In addition, the object detection capabilities of the robotic floor cleaner may be improved. Due to the wide horizontal FOV of the forward-facing camera, the portion of the floor which the robotic floor cleaner has not previously detected or “seen” before it is cleaned (or driven over) by the robotic floor cleaner may be reduced. Thus, a risk of the robotic floor cleaner driving over, or colliding with objects may be reduced. For example, there may be a greater risk of a robotic floor cleaner driving over or colliding with objects when a camera with a smaller horizontal FOV is used, or when, for example, a LiDAR navigation system is used, because a smaller area of the floor may be detectable by such systems. It will be appreciated that the forward-facing camera may face in a direction of (e.g., forward) travel of the robotic floor cleaner (e.g., when the robotic floor cleaner is moving / driving autonomously). The body may have a body axis extending from an upper surface of the body to a lower surface of the body. The body axis may extend centrally through the body. The forwardfacing camera may face in a direction transverse to the body axis. The optical axis of the forward-facing camera (which may correspond to the optical axis of the lens of the camera) may be transverse to the body axis. An optical axis of a lens may refer to the straight line which passes through the geometrical centre of the lens and which joins the two centres of curvature of its surfaces, and / or to the straight line along which the path of a light ray is perpendicular to the surfaces of the lens and, as such, will be unchanged as it passes through the lens from one surface of the lens to the other. It will further be appreciated that a horizontal FOV may refer to FOV in a plane which is parallel to the floor in use. In some examples, the horizontal FOV may be at least 165°, at least 170°, at least 175°, or at least 180°. In this way, the robotic floor cleaner may be better adapted to navigation and / or object detection. In some examples, the horizontal FOV may be no more than 190°, for example no more than 185°, no more than 180°, or no more than 175°. In some examples, the horizontal FOV is at least 165° and not more than 190°. In some examples, the horizontal FOV is at least 175° and not more than 190°. In this way, the camera may be simpler and / or cheaper to manufacture. Further, a size of the camera may be reduced. As an example, the horizontal FOV may be 185°. Such a horizontal FOV may strike a balance between effectiveness of the navigation and / or object detection, and the difficulty and / or cost of manufacture. In some examples, the forward-facing camera may comprise a rectilinear lens. In this way, the efficiency of the forward-facing camera, and / or the quality of the images produced by the forward-facing camera may be improved, because the images produced by the rectilinear lens may more closely approximate the shape of the camera sensor, for example. The camera sensor may be rectilinear or rectangular, and thus a rectilinear image produced by the rectilinear lens may make more efficient use of the camera sensor pixels, as compared to a curvilinear image, which may be produced by a fisheye lens, for example. When the horizontal FOV is no more than 185°, no more than 180°, or no more than 175°, the rectilinear lens may be significantly easier and / or cheaper to manufacture. In some examples, the forward-facing camera may have a vertical FOV of at least 80°, or at least 91°, for example 96°. In this way, the risk of a robotic floor cleaner driving over, or colliding with objects on the floor may be reduced. It will be appreciated that a vertical FOV may refer to a FOV in a plane which is perpendicular to the floor in use. In some examples, the vertical FOV may be no more than 110°, for example no more than 101°. In this way, the camera may be simpler and / or cheaper to manufacture. Further, a size of the camera may be reduced. In some examples, the forward-facing camera may have a diagonal FOV of at least 180°, or at least 189°, for example 194°. In some examples, the forward-facing camera may have a diagonal FOV of no more than 210°, for example no more than 199°. In some examples, the forward-facing camera may be mounted such that its optical axis is at an angle to the horizontal, for example such that the forward-facing camera faces towards the floor in use. The angle that the optical axis makes with the horizontal may be at least 3°, at least 5°, or at least 10 degrees. The angle that the optical axis makes with the horizontal may be no more than 30°, or no more than 20°, or no more than 15°. In this way, the risk of a robotic floor cleaner driving over, or colliding with objects on the floor may be reduced. Additionally, or alternatively in this way the robotic floor cleaner may be adapted for both navigation and object detection using a single camera. In other examples, the forward-facing camera may be mounted such that its optical axis is parallel to the horizontal. In this way, the robotic floor cleaner may be adapted for both navigation and object detection using a single camera. It will be appreciated that “the horizontal” may refer to a horizontal plane, or to a plane parallel to the plane of the floor surface upon which the robotic floor cleaner is travelling. In some examples, the forward-facing camera may be positioned centrally between a leftside surface and a right-side surface of the body. In this way, the camera may be operable to obtain a more uniform image of the robot’s surroundings. In some examples, the optical axis of the forward-facing camera may be equidistant from the left-side surface and the right-side surface of the body. In this way, the optical axis may, in the horizontal plane, extend centrally through the body. Thus, the camera may be operable to obtain a more uniform image of the robot’s surroundings. The side surfaces of the body may be coupled to (e.g., may be integrally formed with) a front surface and / or a back surface of the body. It will be appreciated that the side surfaces of the body may be transverse to the front surface and / or the back surface. In some examples, the forward-facing camera may be mounted to the front surface of the body. Thus, the forward-facing camera may face outwards from a front surface of the body. In this way, the forward-facing camera may better be able to detect objects on the floor. In some examples, the camera may be fixed in position relative to the body. In this way, the robotic floor cleaner may be sturdier and / or less prone to damage. In some examples, the lens of the camera (i.e., the front surface of the lens) may lie flush with respect to the front surface of the body. Tn this way, a majority of the lens, and a majority of the camera may lie behind the front surface of the body, and the camera may be less prone to damage. It will be appreciated that the front surface of the body may face in a (e.g., forward) direction of travel of the robotic floor cleaner (e.g., when the robotic floor cleaner is moving / driving autonomously). The robotic floor cleaner may comprise a cleaner head, which may house a brush bar. The cleaner head may be coupled to and / or may extend outwards from the front surface of the body. The front surface of the body may extend over a portion of the cleaner head. The front surface of the body may be opposite a back surface of the body. The robotic floor cleaner may comprise a separating apparatus, and the back surface of the body may be coupled to the separating apparatus. The separating apparatus may be configured to remove dirt from fluid (e.g., air) drawn into the robotic floor cleaner. In some examples, when the robotic floor cleaner comprises a cleaner head coupled to the front surface of the body, the forward-facing camera may be positioned at least 1cm, or at least 3 cm, and / or no more than 4 cm, or no more than 6 cm above the cleaner head. In this way, the forward-facing camera may be able to detect objects on the floor closer to the robotic vacuum cleaner. Additionally, or alternatively, the proportion of the sensor pixels which are useful for object detection may be increased, because the amount of the cleaner head shown in the image produced by the forward-facing camera may be reduced. In some examples, a height of the body (i.e., along the body axis) may be at least 7 cm (e.g., at least 8 cm) and no more than 11 cm (e.g., at least 10 cm). A height of the cleaner head (i.e., along the body axis) may be at least 1.5 cm (e.g., at least 2.5 cm), and no more than 7 cm (e.g., no more than 60 cm). In some examples, the forward-facing camera is positioned between around 3 cm and 10cm above the floor surface, in normal use. For example, the forward-facing camera may be positioned between 5cm and 8cm above the floor surface in normal use. In preferred embodiments, the forward-facing camera is positioned less than 8cm or less than 7cm above the floor surface in normal use. This may allow reduced height of the robot and improved capture of images of the floor surface immediately in front of the robot. In some examples, the robotic floor cleaner may include an illumination system including one or more light sources. The illumination system may include one or more light guides, each light guide coupled to a respective one of the light sources. The illumination system may be proximate the camera. The illumination system may be mounted to the front surface of the body. In this way, operation of the robotic vacuum cleaner in low light conditions may be improved and / or the quality of the images captured by the forward-facing camera may be improved. Thus, the object detection and / or navigation capabilities of the robotic vacuum cleaner may be improved. For example, the illumination system may include two light sources, the two light sources positioned either side (i.e., positioned laterally on either side) of the camera. In this way, the horizontal FOV may be better and / or more evenly illuminated, and the quality of the images captured may be improved. Thus, the object detection and / or navigation capabilities of the robotic vacuum cleaner may be improved. In some examples, the robotic floor cleaner may comprise a camera housing mounted to the body. The camera housing may house and / or support the camera (including the camera lens and the sensor). The camera housing may further house and / or support the illumination system. The combination of the camera housing, and the components housed within the camera housing may be referred to as a vision system. In some examples, the one or more light sources may comprise one or more light emitting diodes (LEDs). The one or more LEDs may comprise one or more Infrared (IR) (e.g., 850 nm) LEDs. In this way, the illumination system may not be distracting to a user. For example, the one or more light sources (e.g., the IR LEDs) may be switched on at all times when the robotic floor cleaner is moving / driving and / or cleaning. In some examples, the one or more light sources may comprise one or more light sources emitting visible light. By illuminating objects in the vicinity of the robot with visible light, the quality of the images captured by the camera may be improved. Additionally, in this way, a user may also easily ascertain whether the illumination system is working correctly. The camera sensor may be configured to detect IR and / or visible light. In some examples, each of the one or more light sources may provide a horizontal illumination FOV (e.g., as measured from the centre of the respective light source) of at least 120°, or at least 130° and / or no more than 160°, or no more than 150°, for example 140°. In some examples, each of the one or more light sources may provide a vertical illumination FOV (e.g., as measured from the centre of the respective light source) of at least 70°, or at least 80° and / or no more than 110°, or no more than 100°, for example 90°. In this way, the FOV of the camera may be well illuminated. In some examples, the robotic floor cleaner may additionally comprise an upward-facing camera mounted on an upper surface of the body. The upward-facing camera may be an omnidirectional camera, capable of capturing a 360° view of the environment. The upward-facing camera may be a fisheye lens camera or a panoramic annular lens (PAL) camera. In this way, the robotic floor cleaner may be adapted to carry out navigation using the upward facing camera. The upward-facing camera may be unsuitable for carrying out object detection of objects on the floor, for example due to being upward-facing and due to its vertical FOV. In some examples, the robotic floor cleaner may comprise a control system, which may be embodied within the software and / or electronics of the robotic floor cleaner. In some examples, the control system may be configured to receive one or more images captured by the forward-facing camera and / or the upward-facing camera. The control system may further be configured to process the image(s) using a simultaneous localisation and mapping (SLAM) algorithm to navigate the robotic floor cleaner (e.g., using a visual SLAM algorithm). Additionally, or alternatively, the control system may be configured to process the image(s) using an object detection algorithm and, to control the movement of the robotic floor cleaner (e.g., using a traction unit of the robotic floor cleaner), based on the output of the object detection algorithm. For example, the object detection algorithm may receive the image(s), detect one or more objects (e.g., on the floor) in the received image(s). The object detection algorithm may further be configured to, in response to detecting an object in an image, determine a type of object in the image (e.g., whether the object is a sock or a stain), and control the movement of the robotic floor cleaner based on the detection and / or the determination. Additionally, or alternatively, the object detection algorithm may be configured to, in response to detecting an object in an image, approximate a distance of the object from the robotic floor cleaner and control the movement of the robotic floor cleaner based on the detection and / or the approximation. In this way, the robotic floor cleaner may be adapted for both navigation and / or object detection using a single camera. In some examples, the robotic floor cleaner may correspond to a robotic vacuum cleaner and / or to a robotic mop. That is, the robotic floor cleaner may be configured to vacuum clean and / or to mop the floor. In some examples, the robotic floor cleaner may comprise one or more traction units for moving or driving the robotic floor cleaner. In some examples, the robotic floor cleaner may be able to turn on the spot, for example when it approaches an obstacle. For example, a left traction unit and a right traction unit may be driveable (e.g., by the controller) at the same speed but in opposite directions. The horizontal FOV of the forward-facing camera may mean that, the portion of the floor which the robotic floor cleaner has not previously detected before it is cleaned (or driven over) by the robotic floor cleaner may be reduced when the robotic floor cleaner turns on the spot. It will be appreciated that the above examples may be combined in any suitable combination to provide further examples, except where such a combination is clearly impermissible or expressly avoided. BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 shows a robotic floor cleaner according to the present disclosure. Figure 2 shows an exploded view of a vision system according to the present disclosure. Figure 3 a schematic representation of a robotic floor cleaner. DETAILED DESCRIPTION Figure 1 shows a robotic floor cleaner 10 in the form of a robotic vacuum cleaner comprising a body 12 and a separating apparatus 14 coupled to a back surface of the body 12. The body 12 is coupled, at its front surface 18, to a cleaner head 20 which houses a brush bar, through which dirty air can be drawn into the robotic vacuum cleaner 10 and passed into the separating apparatus 14. Once the air has been cleaned of dirt in the separating apparatus 14, it passes out of the separating apparatus 14 and through the body 12 which houses a motor and fan for generating the airflow. The air is then expelled from the robotic vacuum cleaner 10 through an outlet vent. Although not visible in Figure 1, the body 12 is also coupled, on its lower surface to traction units in the form of continuous tank tracks for moving the robotic vacuum cleaner 10. The robotic vacuum cleaner 10 also includes a vision system 22 comprising a camera housing which houses a forward-facing camera 24. The forward-facing camera 24 is mounted, via the camera housing, to the front surface 18 of the body 12, with the lens of the camera 24 lying flush with respect to the front surface 18 of the body 12. The forwardfacing camera 24 is mounted centrally between the left-side and right-side surfaces of the body 12, with its optical axis parallel to the horizontal. The vision system 22 further comprises an illumination system 26 which includes two IR LEDs (configured to produce light at 850 nm) housed within the camera housing, which are positioned on either side of the camera 24. The forward-facing camera 24 has a horizontal FOV of 185°, and a vertical FOV of 96°. This enables the forward-facing camera 24 to be well suited to carry out both navigation and object detection. In addition, in the example shown in Figure 1, an upward-facing camera 28 is mounted on an upper surface of the body 12. The upward-facing camera 28 is an omnidirectional camera, capable of capturing a 360° view (i.e., a 360° horizontal FOV) of the environment surrounding the robotic floor cleaner. The upward-facing camera 28 may be, for example, a fisheye lens camera or a panoramic annular lens (PAL) camera. Thus, the upward-facing camera 28 is well suited to carry out navigation of the robotic vacuum cleaner 10. In other examples, the robotic floor cleaner 10 may not include the upward-facing camera 28, due to the ability of the forward-facing camera 24 to carry out navigation. The robotic floor cleaner 10 comprises a control system, embodied within the software and electronics of the robotic vacuum cleaner 10, which is configured to use simultaneous localisation and mapping (SLAM) techniques to process the images captured by the forward-facing camera 24 and the upward-facing camera 28, which allows the robotic floor cleaner 10 to understand, interpret and autonomously navigate the local environment. The control system is also configured to process the images captured by the forward-facing camera 24 using an object detection algorithm, which allows the robotic vacuum cleaner 10 to avoid obstacles when moving through the local environment. In the example shown in Figure 1, the control system also uses information gathered from a number of other sensors provided on the robotic vacuum cleaner 10, such as a bump sensor, and also comprises a number of position sensors such as position sensitive devices (PSDs) and / or time of flight (ToF) sensors. The PSDs and / or ToF sensors are housed within sensor pods 30 which flank the separating apparatus 14. The sensor pods 30 are provided with transparent covers through which the PSDs and ToF sensors are able to emit and receive light such as infra-red (IR) light. The sensor pods 30 house an array of sensors that are directed in different directions. Downward facing sensors can also detect a drop in the floor surface, often referred to as cliff sensors, such that the robotic vacuum cleaner is able to stop and / or adjust its direction of travel before it travels off a drop such as a staircase. Whilst some robotic vacuum cleaners use moveable bumper portions as physical contact sensors, this robotic vacuum cleaner 10 has a bump sensor which detects relative movement between separate chassis and body 12 portions of the body 12 to register physical contact with an obstacle. In other examples, the robotic floor cleaner 10 may not include the other sensors such as the bump sensor and / or position sensors. Further, although in the example shown in Figure 1, the robotic floor cleaner is in the form of a robotic vacuum cleaner 10, in other examples the robotic floor cleaner may additionally, or alternatively be configured to mop the floor. Figure 2 shows an exploded view of a vision system 22 of a robotic floor cleaner. The vision system 22 comprises a number of components which form both the forward-facing camera 24 and the illumination system 26, housed within a camera housing 32. The components include a lens 34 held by a lens holder 36, a sensor 38 coupled to a PCB 40 and aligned with the lens 34, two LEDs 42 coupled to the PCB 40 on either side of the sensor 38, and two lightguides 44, each aligned with a respective LED 42. These components are housed within the camera housing 32, with screws 46 coupling the PCB 40 to the camera housing 32, and a respective O-ring 48 around each of the lens holder 36 and the lightguides 44. In the example of Figure 2, the horizontal FOV of the forward-facing camera 24 is 185°± 5°, the vertical FOV is 96°± 5°, and the diagonal FOV is 194°± 5°. The sensor 38 comprises a 1920 x 1080 pixel array, and each pixel measures 2.9 pm by 2.9 pm. The forward-facing camera has a focusing range of 11 cm to approximately 66 cm, with an optimum focusing distance of 20 cm. Figure 3 shows a schematic representation of an example of a robotic floor cleaner 10. The robotic floor cleaner 10 comprises a control system 50, a vision system 22, sensors 52, and a drive system 54. The vision system 22 comprises a forward-facing camera 24 and an illumination system 26. As has already been described, the forward-facing camera 24 has a wide horizontal FOV and is capable of capturing images of an area surrounding the robotic floor cleaner 10. The illumination system 26 is able to improve the quality of the images captured by the forward-facing camera 24 when the robotic floor cleaner 10 is located in an environment that has low-light conditions, or where the images captured by the forward-facing camera 24 suffer from poor contrast. The illumination system 26 comprises two LEDs 42 as shown in previous figures. Each one of the LEDs 42 has a corresponding LED driver which is used to drive power to the LED 42. The LEDs 42 emit light of any bandwidth that the forward-facing camera’s 24 sensor 38 is able to detect in order to improve the quality of the images captured by the forward-facing camera 24. For example, the light emitted by the LEDs 42 may be within the visible, or infrared (IR) parts of the electromagnetic spectrum. The control system 50 comprises an object detection unit 56 and a navigation unit 58. The control system 50 may comprise other units not shown in Figure 3 for the control of other systems of the robotic floor cleaner 10, for example the control system 50 may further comprise a task control unit to control a task being carried out by the robotic floor cleaner 10, such as a vacuum cleaning or mopping operation. The control system 50 is responsible for controlling movement of the robotic floor cleaner 10 within its environment. Images taken by the forward-facing camera 24 are fed into the navigation unit 58 and the object detection unit 56 of the control system 50. The navigation unit 58 may be, for example, a simultaneous localisation and mapping (SLAM) unit. A SLAM unit can be used to analyse the images to find landmark features within the area surrounding the robotic floor cleaner 10 shown in the images. Landmark features are high-contrast features that are easily detected within the image, for example the edge of a table, or the comer of a picture frame. The landmark features can then be used by the navigation unit to triangulate and determine the position or pose of the robotic floor cleaner 10 within the environment. The navigation unit can use the information from the images and data captured from other sensors in the robotic floor cleaner 10 to create a map of the environment which the robotic floor cleaner 10 uses to interpret and navigate the environment. The object detection unit 56 can be used to detect objects shown in the images (e.g., objects which are on the floor), which the robotic floor cleaner 10 uses to avoid obstacles when moving through the local environment. Instructions are sent from the control system 50 to the drive system 54 which causes the robotic floor cleaner 10 to move. The drive system 54 comprises a left hand side (LHS) traction unit 55a and a right hand side (RHS) traction unit 55b. Each traction unit can be independently controlled such that the robotic floor cleaner 10 can be steered. For example, if the RHS traction unit 55b is driven in a forward direction faster than the LHS traction unit 55a, then the robotic floor cleaner 10 will veer to the left as it moves forward, or as a further example if the LHS and RHS traction units 55a / b are each driven at the same speed but in opposite directions then the robotic floor cleaner 10 will turn on the spot. In the example shown in Figure 3, the robotic floor cleaner 10 also comprises a system of sensors 52 that provide the robotic floor cleaner 10 with additional information about the surrounding environment, and the robot’s pose within the environment. The sensors system includes a bump sensor 60 and a gyrodometry system 62. The gyrodometry system 62 includes an inertial measurement unit (IMU) 64 and an odometer 66. The odometer 66 receives data from the drive system 54 to provide an indication of the distance travelled by a traction unit (e.g. by using the number of revolutions of a wheel). The bump sensor 60 lets the robotic floor cleaner 10 know when physical contact has been made with an obstacle. In response to a signal from the bump sensor 60, the robotic floor cleaner 10 can for example stop and / or adjust its position and trajectory. This prevents the robotic floor cleaner 10 from causing any damage to itself or to the obstacle with which it has made contact. The sensor system 52 may comprise other sensors which are not shown in Figure 3, for example one or more proximity sensors such as PSDs and / or ToF sensors. Proximity sensors are able to give an indication of any obstacles that may be near the robotic floor cleaner 10. This allows the robotic floor cleaner 10 to avoid obstacles without making contact with them. Such sensors may however be unnecessary due to the wide FOV of the forward-facing camera 24.

Claims

1. A robotic floor cleaner comprising:a body; anda forward-facing camera coupled to the body, wherein the forward-facing camera has a horizontal field of view of at least 160°.

2. A robotic floor cleaner according to claim 1, wherein the horizontal field of view is no more than 190°.

3. A robotic floor cleaner according to any of the preceding claims, wherein the forwardfacing camera comprises a rectilinear lens.

4. A robotic floor cleaner according to any of the preceding claims, wherein the forwardfacing camera has a vertical field of view of at least 80°.

5. A robotic floor cleaner according to claim 4, wherein the vertical field of view is no more than 110°.

6. A robotic floor cleaner according to any of the preceding claims, wherein the forwardfacing camera is mounted such that its optical axis is at an angle to the horizontal.

7. A robotic floor cleaner according to claim 6, wherein the angle is no more than 15°.

8. A robotic floor cleaner according to any of the preceding claims, wherein the forwardfacing camera is positioned centrally between a left-side surface and a right-side surface of the body.

9. A robotic floor cleaner according to any of the preceding claims, wherein the forwardfacing camera is mounted to a front surface of the body.

10. A robotic floor cleaner according to any of the preceding claims further comprising a cleaner head extending outwards from a front surface of the body, wherein the forwardfacing camera is positioned at least 2 cm above the cleaner head.

11. A robotic floor cleaner according to any of the preceding claims, further comprising an illumination system including one or more light sources.

12. A robotic floor cleaner according to claim 11, wherein the illumination system comprises one or more infrared LEDs.

13. A robotic floor cleaner according to any of the preceding claims, further comprising an upward-facing camera mounted on an upper surface of the body.

14. A robotic floor cleaner according to any of the preceding claims, further comprising a control system configured to:receive one or more images captured by the forward-facing camera; and,process the image(s) using a simultaneous localisation and mapping algorithm to navigate the robotic floor cleaner.

15. A robotic floor cleaner according to any of the preceding claims, further comprising a control system configured to:receive one or more images captured by the forward-facing camera;process the image(s) using an object detection algorithm; and,control the movement of the robotic floor cleaner based on the output of the object detection algorithm.

Images