VEHICLE, APPARATUS AND METHOD

Abstract

A vehicle (1), preferably an unmanned and/or autonomous vehicle, for example a robot, the vehicle (1) comprising: a propulsion system (10), arranged to propel the vehicle (1), comprising a set of wheels (11) including a first wheel (11A) and/or a set of tracks (12) including a first track (12A); a deposition apparatus (20) for depositing a foam F comprising a polymeric composition (PC); and a controller (30) arranged to control the deposition apparatus (20) and optionally, the propulsion system (10); wherein the deposition apparatus (20) comprises: a set of reservoirs (100), including a first reservoir (100A) and a second reservoir (100B) arranged to receive therein a first component (C1) and a second component (C2) of the polymeric composition (PC), respectively; optionally a set of pumps (200), including a first pump (200A) and a second pump (200B) arranged to pump the first component (C1) and the second component (C2) from the first reservoir (100A) and the second reservoir (100B), respectively; a blending chamber (300) in fluid communication with the set of reservoirs (100) via a set of inlet passageways (400), including a first inlet passageway (400A) and a second inlet passageway (400B), wherein the blending chamber (300) is arranged to blend the first component (C1) and the second component (C2) thereinto provide a precursor (P) of the poly-meric composition (PC); and a set of deposition nozzles (500) in fluid communication with the blending chamber (300) via a set of outlet passageways (600) including a first outlet passageway (600A), the set of deposition nozzles (500) including a first deposition nozzle (500A) comprising a static mixer (700A) arranged to mix the precursor (P) to generate the foam (F), at least in part, therefrom.

Claims

1. A vehicle comprising: a propulsion system, arranged to propel the vehicle, comprising a set of wheels including a first wheel and/or a set of tracks including a first track; a deposition apparatus for depositing a foam comprising a polymeric composition; and a controller arranged to control the deposition apparatus or the deposition apparatus and the propulsion system; wherein the deposition apparatus comprises: a set of reservoirs, including a first reservoir and a second reservoir arranged to receive therein a first component and a second component of the polymeric composition, respectively; a set of pumps, including a first pump and a second pump arranged to pump the first component and the second component from the first reservoir and the second reservoir, respectively; a blending chamber in fluid communication with the set of reservoirs via a set of inlet passageways, including a first inlet passageway and a second inlet passageway, wherein the blending chamber is arranged to blend the first component and the second component therein to provide a precursor of the polymeric composition; and a set of deposition nozzles in fluid communication with the blending chamber via a set of outlet passageways including a first outlet passageway, the set of deposition nozzles including a first deposition nozzle comprising a static mixer arranged to mix the precursor to generate the foam, at least in part, therefrom.

2. The vehicle according to claim 1, wherein the set of deposition nozzles includes a second deposition nozzle in fluid communication with the blending chamber via a second outlet passageway of the set of outlet passageways.

3. The vehicle according to claim 1 any previous claim: wherein the set of reservoirs includes a third reservoir arranged to receive therein a solvent for cleaning the blending chamber, the set of outlet passageways and/or the set of deposition nozzles; wherein the set of pumps includes a third pump arranged to pump the solvent from the third reservoir; and wherein the set of inlet passageways includes a third inlet passageway.

4. The vehicle according to claim 1, wherein the first pump includes a peristaltic pump.

5. The vehicle according to claim 1, wherein the first deposition nozzle is arranged forwardly of the set of wheels, forwardly of the first wheel, and/or forwardly of the set of tracks.

6. The vehicle according to claim 1, wherein the first deposition nozzle is arranged aligned with the set of wheels, preferably aligned with the first wheel, and/or aligned with the set of tracks.

7. The vehicle according to claim 1, further comprising a set of sensors including a first sensor arranged to sense an obstacle and to transmit a first signal to the controller, in response to sensing the obstacle.

8. The vehicle according to claim 7, wherein the controller is arranged to receive the first signal transmitted by the first sensor and to control the propulsion system and/or the deposition apparatus, based, at least in part, on the received first signal.

9. The vehicle according to claim 8, wherein the controller is arranged to control the propulsion system to move the vehicle rearwardly or forwardly and to control the deposition apparatus to deposit the foam, based, at least in part, on the received first signal.

10. The vehicle according to claim 9, wherein the controller is arranged to control the propulsion system to move the vehicle rearwardly and to control the deposition apparatus to deposit the foam, based, at least in part, on the received first signal, while the vehicle moves rearwardly.

11. The vehicle according to claim 10, wherein the controller is arranged to control the propulsion system to move the vehicle forwardly after depositing the foam.

12. The vehicle according to claim 9, wherein the controller is arranged to control the propulsion system to move the vehicle forwardly and to control the deposition apparatus to deposit the foam, based, at least in part, on the received first signal, while the vehicle moves forwardly.

13. A method of controlling a vehicle according to claim 1 to deposit a foam comprising a polymeric composition, the method comprising: blending, using the blending chamber, the first component and the second component of the polymeric composition to provide the precursor of the polymeric composition; generating the foam, at least in part, by mixing, using the static mixer included in the first deposition nozzle, the precursor; and depositing the foam, at least in part, via the first deposition nozzle.

14. A deposition apparatus for depositing a foam comprising a polymeric composition, the deposition apparatus comprising: a set of reservoirs, including a first reservoir and a second reservoir arranged to receive therein a first component and a second component of the polymeric composition, respectively; a set of pumps, including a first pump and a second pump arranged to pump the first component and the second component from the first reservoir and the second reservoir, respectively; a blending chamber in fluid communication with the set of reservoirs via a set of inlet passageways, including a first inlet passageway and a second inlet passageway, wherein the blending chamber is arranged to blend the first component and the second component therein to provide a precursor of the polymeric composition; and a set of deposition nozzles in fluid communication with the blending chamber via a set of outlet passageways including a first outlet passageway, the set of deposition nozzles including a first deposition nozzle comprising a static mixer arranged to mix the precursor to generate the foam, at least in part, therefrom.

15. A method of depositing a foam comprising a polymeric composition, the method comprising: blending, using a blending chamber, a first component and a second component of the polymeric composition to provide a precursor of the polymeric composition; generating the foam, at least in part, by mixing, using a static mixer included in a first deposition nozzle, the precursor; and depositing the foam, at least in part, via the first deposition nozzle.

16. (canceled)

17. The vehicle according to claim 5, wherein the first deposition nozzle is arranged forwardly of the first track.

18. The vehicle according to claim 6, wherein the first deposition nozzle is arranged aligned with the first track.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0134] For a better understanding of the invention, and to show how exemplary embodiments of the same may be brought into effect, reference will be made, by way of example only, to the accompanying diagrammatic Figures, in which:

[0135] FIG. 1 schematically depicts a vehicle according to an exemplary embodiment;

[0136] FIG. 2 schematically depicts a method of depositing a foam according to an exemplary embodiment;

[0137] FIG. 3 shows stress-strain curves of polyurethane foams;

[0138] FIGS. 4A (front perspective view) and 4B (plan view) are photographs of a part of a vehicle according to an exemplary embodiment;

[0139] FIG. 5A schematically depicts a method of controlling the vehicle of FIGS. 4A and 4B according to an exemplary embodiment and FIG. 5B schematically depicts the vehicle, in use, controlled according to the method of FIG. 5A;

[0140] FIG. 6A schematically depicts a method of controlling the vehicle of FIGS. 4A and 4B according to an exemplary embodiment and FIG. 6B schematically depicts the vehicle, in use, controlled according to the method of FIG. 6A;

[0141] FIGS. 7A (plan view) and 7B (front perspective view) are photographs of the vehicle of FIGS. 4A and 4B, in more detail;

[0142] FIG. 8 is a time series of photographs (side elevation view) of the vehicle of FIGS. 4A and 4B, in use;

[0143] FIG. 9A is a time series of photographs (side elevation view) of the vehicle of FIGS. 4A and 4B, in use, and FIG. 9A is a time series of photographs (plan view) of the vehicle of FIGS. 4A and 4B, in use;

[0144] FIG. 10 is a time series of photographs (side elevation view) of the vehicle of FIGS. 4A and 4B, in use;

[0145] FIG. 11A is a CAD perspective view and FIG. 11B is a schematic cross-sectional view of a blending chamber of the deposition apparatus of the vehicle of FIGS. 4A and 4B;

[0146] FIG. 12 is a photograph (perspective view) of a deposition nozzle of the deposition apparatus of the vehicle of FIGS. 4A and 4B;

[0147] FIG. 13 schematically depicts a method of controlling a vehicle to deposit a foam comprising a polymeric composition according to an exemplary embodiment; and

[0148] FIG. 14 schematically depicts a method of depositing a foam comprising a polymeric composition according to an exemplary embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

[0149] Vehicle

[0150] FIG. 1 schematically depicts a vehicle 1 according to an exemplary embodiment. The vehicle 1 is preferably an unmanned and/or autonomous vehicle, for example a robot. The vehicle 1 comprises: a propulsion system 10, arranged to propel the vehicle 1, comprising a set of wheels 11 including a first wheel 11A and/or a set of tracks 12 including a first track 12A; a deposition apparatus 20 for depositing a foam F comprising a polymeric composition PC; and a controller 30 arranged to control the deposition apparatus 20 and optionally, the propulsion system 10. The deposition apparatus 20 comprises a set of reservoirs 100, including a first reservoir 100A and a second reservoir 100B arranged to receive therein a first component C1 and a second component C2 of the polymeric composition PC, respectively; optionally a set of pumps 200 (not shown), including a first pump 200A (not shown) and a second pump 200B (not shown) arranged to pump the first component C1 and the second component C2 from the first reservoir 100A and the second reservoir 100B, respectively; a blending chamber 300 in fluid communication with the set of reservoirs 100 via a set of inlet passageways 400, including a first inlet passageway 400A and a second inlet passageway 400B, wherein the blending chamber 300 is arranged to blend the first component C1 and the second component C2 therein to provide a precursor P of the polymeric composition PC; and a set of deposition nozzles 500 in fluid communication with the blending chamber 300 via a set of outlet passageways 600 including a first outlet passageway 600A, the set of deposition nozzles 500 including a first deposition nozzle 500A comprising a static mixer 700A arranged to mix the precursor P to generate the foam F, at least in part, therefrom.

[0151] Example Vehicle

[0152] This section describes the design of a foam mixing and depositing device (i.e. a deposition apparatus 20), the characterisation of the foam produced by this device and the integration with an autonomous ground tracked vehicle 2, generally as described with respect to the vehicle 1. Like reference signs denote like features.

[0153] In more detail, the vehicle 2 is an autonomous vehicle. The vehicle 2 comprises: a propulsion system 10, arranged to propel the vehicle 1, comprising a set of tracks 12 including a first track 12A and a second track 12B; a deposition apparatus 20 for depositing a foam F comprising a polymeric composition PC; and a controller 30 arranged to control the deposition apparatus 20 and optionally, the propulsion system 10. The deposition apparatus 20 comprises a set of reservoirs 100, including a first reservoir 100A and a second reservoir 100B arranged to receive therein a first component C1 and a second component C2 of the polymeric composition PC, respectively; a set of pumps 200, including a first pump 200A and a second pump 200B arranged to pump the first component C1 and the second component C2 from the first reservoir 100A and the second reservoir 100B, respectively; a blending chamber 300 in fluid communication with the set of reservoirs 100 via a set of inlet passageways 400, including a first inlet passageway 400A and a second inlet passageway 400B, wherein the blending chamber 300 is arranged to blend the first component C1 and the second component C2 therein to provide a precursor P of the polymeric composition PC; and a set of deposition nozzles 500 in fluid communication with the blending chamber 300 via a set of outlet passageways 600 including a first outlet passageway 600A and a second outlet passageway 600B, the set of deposition nozzles 500 including a first deposition nozzle 500A comprising a static mixer 700A and a second deposition nozzle 500B comprising a static mixer 700B arranged to mix the precursor P to generate the foam F, at least in part, therefrom.

[0154] In this example, the first deposition nozzle 500A is arranged forwardly of the first track 12A. In this example, the second deposition nozzle 500B is arranged forwardly of the second track 12B. In this example, the first deposition nozzle 500A is arranged aligned with the first track 12A. In this example, the second deposition nozzle 500B is arranged aligned with the second track 12B.

[0155] In this example, the propulsion system 10 comprises a set of actuators 13, including a first actuator 13A and a second actuator 13B, arranged to actuate the set of tracks 12, particularly the first track 12A and the second track 12B respectively. In this example, the first actuator 13A and the second actuator 13B are motors, as described below.

[0156] In this example, the set of reservoirs 100 includes a third reservoir 100C arranged to receive therein a solvent for cleaning the blending chamber 300, the set of outlet passageways 600 and the set of deposition nozzles 500. In this example, the set of pumps 200 includes a third pump 200C arranged to pump the solvent from the third reservoir 100C and the set of inlet passageways 400 includes a third inlet passageway 400C.

[0157] In this example, the vehicle 2 comprises a set of sensors 800 including a first sensor 800A arranged to sense an obstacle O and to transmit a first signal to the controller 30, in response to sensing the obstacle O. In this example, the first sensor 800A is a proximity sensor, particularly an ultrasonic sensor. In this example, the first sensor 800A comprises an array of ultrasonic sensors.

[0158] In this example, the controller 30 comprises a processor and a memory and is arranged to control the deposition apparatus 20 and optionally, the propulsion system 10, according to software (i.e. programmatic instructions executed by the processor). In this example, the controller 30 is arranged to receive the first signal transmitted by the first sensor and to control the propulsion system 10 and/or the deposition apparatus 20, based, at least in part, on the received first signal. In this example, the controller 30 is arranged to control the propulsion system 10 to move the vehicle 2 rearwardly or forwardly and to control the deposition apparatus 20 to deposit the foam F, based, at least in part, on the received first signal. In this example, the controller 30 is arranged to control the propulsion system 10 to move the vehicle 2 rearwardly and to control the deposition apparatus 20 to deposit the foam F, based, at least in part, on the received first signal, while the vehicle 2 moves rearwardly. In this example, the controller 30 is arranged to control the deposition apparatus 20 to deposit the foam F, based, at least in part, on a distance from an obstacle O, for example as determined from the received first signal. In this example, the controller 30 is arranged to control a rate of deposition of the foam F by the deposition apparatus 20, based, at least in part, on a distance from an obstacle O, for example as determined from the received first signal. In this example, the controller 30 is arranged to control the propulsion system 10 to move the vehicle 2 forwardly after depositing the foam F. In this example, the controller 30 is arranged to control the propulsion system 10 and/or the deposition apparatus 20 to repeatedly move the vehicle 2 and/or deposit the foam F. In this way, the vehicle 2 may overcome a relatively larger obstacle O. In this example, the controller 30 is arranged to control the propulsion system 10 to move the vehicle 2 forwardly and to control the deposition apparatus 20 to deposit the foam F, based, at least in part, on the received first signal, optionally while the vehicle 2 moves forwardly. In this example, the controller 30 is arranged to control a speed of the set of pumps 200, for example respective speeds of the first pump 200A and the second pump 200B, as a function of time. In this example, the controller 30 is arranged to control a speed of the set of pumps 200, for example respective speeds of the first pump 200A and the second pump independently 200B. In this example, the controller 30 is arranged to calculate a distance from the object O, based, at least in part, on the first signal. In this example, the controller 30 is arranged to calculate a depth and/or a volume of a void, such as a chasm, based, at least in part, on the first signal. In this example, the controller 30 is arranged to calculate an amount of the first component C1 and/or the second component C2 to be deposited as the polymeric composition PC based, at least in part, on the first signal, for example by using the volume of the void to be filled and an expected expansion of the foam F.

[0159] Deposition Apparatus

[0160] PU is a synthetic resin composed of polymer units linked by urethane groups. The two part constituents must be combined with enough vigour for reaction, upon doing so the mix quickly expands and then sets rigid. Expansion typically occurs within 30-50 seconds and solifidication may take up to 8 minutes. The final mechanical properties of the PU foam are significantly affected by the mix ratio of the two constituent parts, and therefore can be tuned with relative ease. Compressive strengths of over 2 MPa are possible, so that the solidified foam can easily support the weight of a human standing on it. Expansion ratios of over 30× the original volume are viable, meaning that 25 dm.sup.3 of solidified foam can be generated from just 0.84 dm.sup.3 of the two part liquid constituents. These values depend largely on the mixing style and have been recorded through testing on the proposed system, as discussed below. The foam in its final state is closed-cell, water-proof and lighter than water yet, as mentioned, still strong enough to support the weight of a human climbing thereon. Additionally, these foams adhere to a wide variety of materials including wood, iron, and concrete, among others. Based on these characteristics, this material is suitable for use in disaster scenarios in real-time.

[0161] The foam was generated from POLYCRAFT PU5800 (available from MBFibreglass, UK), provided as a two-part pack comprising POLYCRAFT PU5800 PART A and POLYCRAFT PU5800 PART (i.e. the first component C1 and the second component C2 of the polymeric composition PC, respectively). POLYCRAFT PU5800 PART A comprises DIPROPYLENE GLYCOL (CAS 110-98-5) 1-25% and N,N,N′,N′-TETRAMETHYL-2,2′-OXYBIS(ETHYLAMINE) (CAS 3033-62-3) 0.05-1% by volume. POLYCRAFT PU5800 PART A comprises DIPHENYLMETHANE DIISOCYANATE (ISOMERS AND HOMOLOGUES) (CAS 9016-87-9).

[0162] Peristaltic pumps (i.e. the first pump 200A and the second pump 200B) (9QX Peristaltic Pump 24V 3 Roller Stepper Motor available from Boxer GmbH, Germany) are used to drive PU part one and two (i.e. part A and part B) from their separate reservoirs (i.e. the first reservoir 100A and the second reservoir 100B, respectively) to the blending chamber 300 via respective inlet passageways (i.e. the first inlet passageway 400A and the second inlet passageway 400B) (Tubing type: PHI 3.5×5.6 mm, 1.05 mm wall available from Boxer GmbH, Germany). This blending chamber 300 ensures the two parts have been thoroughly mixed without increasing the turbulence to such an extent that the parts begin reacting. This mixing is necessary as multiple outlets may be required, and the viscous nature of the individual parts would otherwise make them flow without mixing. The now combined PU (i.e. the precursor P) is split across different channels (i.e. the first outlet passageway 600A and the second outlet passageway 600B) and passed through static mixing nozzles (MA6.3-21S, Adhesive Dispensing Ltd, UK) before being ejected at the outlets (i.e. the first deposition nozzle 500A and the second deposition nozzle 500B). A major drawback of conventional apparatuses is the blockage that occurs between uses, and even during use. This happens as residues, if not treated, will be left in the system and particularly in the static mixing nozzles. As the parts begin to react they become very adhering and as they expand often cause channels to become completely blocked. For the system, a solvent (isopropyl alcohol), driven by a third peristaltic pump (i.e. the third pump 200C) (9QX Peristaltic Pump—DC/Gear Motor 520 rpm 12V-3 roller available from Boxer GmbH, Germany), is then autonomously flushed through the set of inlet passageways 400, the blending chamber 300, the set of outlet passageways 600 and the set of deposition nozzles 500 at the end of each depositing phase to stop the reaction and eject any residue. This allows the deposition apparatus 20 to be used multiple times without blockage or manual intervention. The whole process is illustrated in FIG. 2.

[0163] In more detail, FIG. 2 illustrates the stages of pumping PU part one and two to create PU foam and the solvent flush stages: a) pumping of PU part one and two to create first batch of PU foam; b) flush of solvent to ensure no blockages after use; c) pumping of PU part one and two to create second batch of PU foam; d) flush of solvent. Peristaltic pumps are represented by red symbols, central pentagon represents the mixing chamber and crossed cylinder represent the static mixing nozzles.

[0164] Driving the system with independent peristaltic pumps produces several advantages over current systems. Firstly, the amount of liquid being driven at any point is equal to the volume inside the tubing and mixing devices, and is thus independent of the size of the reservoir from which it is being pumped. This implies that the flow generated by the pump is not affected by the size of the reservoirs, unlike conventional deposition apparatuses, and therefore the system can be significantly scaled without redesign, allowing large amount of material deposition.

[0165] Furthermore, the system can control the flow rate of each pump independently so that the ratio between PU Part one and Part two can be easily controlled. Such ratio controls the properties of the solidified foam, as previously mentioned. For example, if the system required a harder deposit, it could autonomously increase the ratio of PU Part one to the mix. Likewise, increasing the ratio of PU Part two would increase expansion ratio; this could be necessary if maximising the volumetric output was required. Additionally, increasing overall flow velocity increases the turbulence during the mixing of chemicals, thus reducing the time taken to begin expansion. This has the potential to allow the deposited material to be less fluid-like and immediately sticky, with obvious applications for foam deposition on vertical surfaces or gradients. Alternatively, making the deposited material more liquid-like on exit allows deposition into crevices and cracks for structural stabilisation. These options would not be possible for current state of the art syringe or aerosol depositing systems. However, increasing the rate of reaction above a certain level makes the substance more likely to block the static-mixers and thus a maximum overall pump speed is set to prevent this. Finally, the system allows the pumps to drive the liquids to two outlets, although it is possible to increase this number.

[0166] Foam Characterisation

[0167] Four different PU foams obtained via the proposed depositing device are characterised in this section in terms of their most relevant properties: mix ratio, expansion ratio, initial compressive strength, final compressive strength, rise time and set time. Note that the values reported for these four PU foams do not represent the upper and lower limits for properties such as compressive strength and expansion ratio. However, mixes that result in higher expansion ratios result in compressive strengths that may be too low for the deposit to be considered useful for structural applications but may be useful for insulation or buoyancy, for example. Conversely, mixes that result in lower expansion ratios result in compressive strengths that may be sufficient for the deposit to be considered useful for structural applications but may be less useful or non-economic for insulation or buoyancy, for example. In other words, a desired ratio may be selected for a particular application, to balance mechanical properties such as compressive strength, physical properties such as density, thermal properties such as thermal conductivity, curing time and/or cost.

[0168] Mix ratio considers the volumetric ratio between PU foam Part one and Part two, and it is controlled via the pump rates of the peristaltic pumps. Expansion ratios were measured by depositing the PU foam into a container and comparing the initial height of the deposited foam, with the final height of the deposited foam after the expansion had occurred. This method provides conservative estimates of expansion ratios as deposition in free space (e.g. on a surface exposed to air) allows more oxidation to occur, and therefore more expansion. However, depositing on a free surface would make it impossible to have consistency due to the different shapes assumed by the deposit.

[0169] Typically, maximum compressive strength considers the amount of force applied per unit area until a material fails, where failure is often defined by the material cracking. However, PU foam, unlikely many solid materials, will continue to deform with sufficient pressure without breakage. Therefore, two alternative definitions of compressive strength are used here: initial compressive strength and final compressive strength. The former is defined as the pressure applied before permanent plastic deformation occurs, and is highlighted with the symbol ‘X’ in FIG. 3. FIG. 3 shows stress-strain curves of the foam for different mix ratios, see also Table 2. Final compressive strength is defined as the pressure at which the height of the deposit is reduced by 70%, as shown in FIG. 3 with the symbol ‘+’ Beyond this point the deposit is considered useless for overcoming obstacles.

[0170] Rise time is measured from initial deposition until final expansion has occurred. Finally, set time is measured from initial deposition until the foam has fully solidified, this is done by comparing stiffness until it is deemed the material is no longer solidifying and the material is immediately tested in the Instron machine (INSTRON 3345) loading the specimens at 2 mm/min. More importantly than the absolute values of the properties measured for the different PU foams are their relative differences, as they prove that the proposed deposit system can easily control the properties of the deposited material. A summary of properties of the deposited foams are reported in Table 2, where each foam is defined by the mix ratio of Part one to Part two.

TABLE-US-00002 TABLE 2 Characterisation of four types of PU foam Medium- Medium- Low Low High High Density Density Density Density Mix Ratio (one:two) 1:0.74 1:1 1:1.4 1:1.6 Expansion Ratio 33x 29x 25x 2x Initial Compressive 0:16M 0:25 0:41 0:76 Strength (MPa) Final Compressive 0.56 0.74 1:37 2 Strength (MPa) Rise Time (s) 37 46 52 55 Set Time (s) 210-270 240-300 270-340 310-380

[0171] Robotic Platform

[0172] The PU depositing system has the potential to be combined with any existing robotic platform to extend its ability. For the purposes of testing, the simple low cost ground rover (i.e. the vehicle 2) shown in FIGS. 4A and 4B was used.

[0173] This platform is a two-tracked vehicle with a track height of 100 mm and a track length of 300 mm. The rover has a pressure value of 0.02 MPa (15 kg rover on the total surface area of its tracks), making any of the earlier defined foams suitable for the platform. The platform is driven by two large stepper motors (RB-Phi-266, Robotshop), which would allow a 50 kg payload to be pulled along an even medium friction surface. The rover is driven by a central Arduino Mega 2560 board (i.e. the controller 30) which controls the motor speeds via two Arduino Nano boards and the pumping systems via another Arduino Mega 2560. A digital compass is connected to the central control board to feed orientation information back to the controller and positional information is calculated from the localisation system, as described below. The PU foam depositing system was mounted on top of the rover with the two outlets positioned directly behind the tracks. As the rover moves, the foam will be deposited, forming two distinct extrusions which are aligned with the rovers tracks. Once the foam has expanded and solidified, the rover can simply climb on said extrusions to increase or maintain altitude. When depositing foam in a straight line, controlling either deposit speed or rover speed allows the platform to create ramp structures, as described below.

[0174] Experimental Setup

[0175] Two main experiments are designed to demonstrate the effectiveness of the proposed PU foam depositing system: obstacle climbing and chasm traversing.

[0176] Sensing and Depositing Strategies

[0177] Ultrasonic distance sensors (HC-SR04) are utilised to determine the presence of obstacles or chasms in front of the vehicle. If an object is detected, a ramp construction procedure is initiated, whereas a void filling function is executed if a chasm is present.

[0178] Frontal Object Detection

[0179] One sensor is placed at the front of the rover, at just above half of the rover track height. It was determined through testing that if an object is detected at this height or above, the rover will not be able to overcome it independently. As the rover cannot sense if the object is perpendicular to its path, once the object is detected, the rover will begin to move forward at a low motor torque to align the rover front face with the straight edge of an object upon contact. Once the frontal face of the rover has been aligned with the object, the depositing protocol will begin. For this, predetermined deposit rate/time sequence is initiated that will produce a ramp that allows the rover to overcome an obstacle at half of the rover track height. Testing was done to determine the maximum ramp angle for the rover, the deposit sequence ensures that the angle of the ramp is well below this threshold. Delays are also preset to ensure full foam set and curing time. If an obstacle is detected after climbing on this deposit, then the same procedure will be repeated, but with increased ramp length, thus ensuring angle of ramp below maximum ramp angle. The rover can overcome minor over/under expansions for frontal obstacles that may occur. The ramp building protocol, described in the flowchart of FIGS. 5A and 5B is then initiated, giving rise to the responses illustrated in the same figure. FIG. 5A Flowchart and FIG. 5B are illustrations of the frontal object detection system and ramp building

[0180] Chasm Detection

[0181] The chasm detection scenario considers detecting large gaps in the floor preventing path following. The rover used for testing can overcome chasms of up to 100 mm (one third of the total length) without falling into said gap, but longer gaps would prevent its motion. To address this challenge, two sensors are placed on the undercarriage of the chassis, facing the ground: one is positioned at the front of the rover and other at around one third of the rover length from the front. If both forward and centre undercarriage sensors detect a continuous gap, the rover will stop moving and initiate a void filling procedure. At first, the rover uses depth measurements of the chasm to estimates the amount of deposit required. However, if it under deposited (for example if the chasm was not uniform and larger than expected) then it would once again detect the chasm and repeat the filling procedure. Over-depositing typically leads to foam overflowing the chasm, but the extra amount is usually trivial for the rover to overcome. A flowchart of autonomous response to chasms and respective illustration for the responses are shown in FIGS. 6A and 6B. Chasm detection is overridden when climbing a ramp produced by the system.

[0182] Localisation Platform

[0183] During the experimental tests the rover is tasked with following a desired path within a 4.3 m by 3.1 m arena and the obstacle avoidance protocols described above activate if said path is being blocked. To perform path following, a low-cost localisation system based on ultrasonic sensing and time difference of arrival was designed. The compact ultrasound emitter shown in FIGS. 7A and 7B was designed to generate omnidirectional train of ultrasound pulses which are then picked up by several fixed receivers measuring the time difference of arrival. A least squares approach is used to analytically obtain a first estimate of the emitter position, which is then refined through steepest descent optimisation. All processing is done via a standard Arduino platform, proving the low computational demands of the method. Localisation results have been validated against a state-of-the-art Optitrack motion capture system composed of 8 Prime17W cameras, to validate onboard determination of the rover, using the onboard ultrasound localisation system, against the external motion capture system. The ultrasound localisation system allows estimation of rover position within an accuracy of better than 3 cm over 89% of arena and better than 1 cm over 43% of the arena. Overall, the mean localisation error is 1.57 cm and the average standard deviation is 1.39 cm throughout the arena, making it suitable for being embedded on the mobile robotic platform used for the experiments. Three experiments were carried out with both detection systems being operational. The rover is given a straight line path to follow, but if any object is detected along this path the vehicle must work out how best to overcome it. All three experiments require the ability to: i) detect an obstacle that prevents the rover from following the planned path ii) eject the PU foam correctly iii) flush the system to ensure no blockages occur iv) wait until the foam has cured and then overcome obstacle using the deposited foam. The first two experiments consider frontal obstacles and the third considers chasm detection. For all three tests the mix ratio of PU Part one:Part two was fixed at 1:1 (Medium-Low Density foam) so that it can settle within 6 minutes, expand around 29× and have sufficient strength to support the rover weight. All three of these obstacles have been tested to ensure that the rover could not overcome them without using the PU depositing system: with the rover toppling/not able to grip onto the material for the frontal objects or getting stuck in the chasm. Total run time is taken from the moment the object is detected until the time the object has been fully overcome (the entire rover is atop the object or passed the chasm).

[0184] Small Frontal Object Test

[0185] In the first experiment, a 60 mm high block—60% of the 100 mm rover height—was placed along the desired path. The rover detected the object, aligned itself and began the ramp deposit procedure. The vehicle created the ramp by varying pump speed as it moved away at a constant speed so that more material was deposited closer to the object, as shown in FIG. 8. The platform then waited for the foam to expand and solidify before using the deposit to continue its path. No further obstacle was detected and the rover could successfully climb onto the object. The total time to run this experiment was 6 minutes and 42 seconds.

[0186] FIG. 8.1: The vehicle 2 approaches the obstacle O (i.e. the 60 mm high block).

[0187] FIG. 8.2: The vehicle 2 moves away from the obstacle O and turns around, such that the set of deposition nozzles 500 face the object O.

[0188] FIG. 8.3: The vehicle 2 moves towards the obstacle O, senses the obstacle O and stops.

[0189] FIG. 8.4: The vehicle 2 moves rearwardly while depositing the PU foam F as two lines, the rate of depositing decreasing as the vehicle 2 moves further away from the obstacle O.

[0190] FIG. 8.5: The deposited PU foams to provide the foam F.

[0191] FIG. 8.6: The deposited PU continues to foam, defining a ramp, and cures.

[0192] FIG. 8.7: The vehicle 2 climbs the ramp and moves towards the obstacle O.

[0193] FIG. 8.8: The vehicle 2 climbs from the ramp onto the obstacle O.

[0194] FIG. 8.9: The vehicle 2 is fully on the obstacle O.

[0195] Large Frontal Object Test

[0196] In the second experiment, a 130 mm high block—130% times the rover height—was placed along the planned path. The rover detected the object and conducted the same first layer ramp deposit procedure as in the previous experiment. However, upon climbing the ramp it detects the object again. Knowing it has previously deposited a ramp, the rover initiates the ramping procedure but deposits foam for an increased distance compared to the previously created ramps. The platform then waited for the second layer to cure and was able to overcome the object, as shown in FIGS. 9A and 9B. The success of this test proves that building large, multi-layered ramp structures is possible and that the system ensures no blockages occur between layers/uses. Total time for this experiment was 13 minutes and 42 seconds.

[0197] FIG. 9A.1 and FIG. 9B.1: The vehicle 2 approaches the obstacle O (i.e. the 120 mm high block).

[0198] FIG. 9A.2 and FIG. 9B.2: The vehicle 2 moves towards the obstacle O, senses the obstacle O and stops. The vehicle 2 moves rearwardly while depositing the PU foam F as two lines, the rate of depositing decreasing as the vehicle 2 moves further away from the obstacle O.

[0199] FIG. 9A.3 and FIG. 9B.3: The deposited PU foams to provide the foam F. The deposited PU continues to foam, defining a ramp, and cures.

[0200] FIG. 9A.4 and FIG. 9B.4: The vehicle 2 climbs the ramp, moves towards the obstacle, senses the obstacle O and stops.

[0201] FIG. 9A.5 and FIG. 9B.5: The vehicle 2 moves rearwardly while depositing a second layer of PU foam F2 as two lines on top of the previously-deposited foam F, the rate of depositing decreasing as the vehicle 2 moves further away from the obstacle O, repeating steps 9.2-9.4 for longer time/distance to create a longer ramp.

[0202] FIG. 9A.6 and FIG. 9B.6: The deposited PU foams to provide the foam F2. The deposited PU continues to foam, defining a higher ramp, and cures.

[0203] FIG. 9A.7 and FIG. 9B.7: The vehicle 2 climbs the ramp and moves towards the obstacle O.

[0204] FIG. 9A.8 and FIG. 9B.8: The vehicle 2 climbs from the ramp onto the obstacle O.

[0205] FIG. 9A.9 and FIG. 9B.9: The vehicle 2 is fully on the obstacle O.

[0206] Chasm Test

[0207] In the final experiment a 160 mm long chasm was placed along the rover's path, over half the 300 mm rover tracks length. The chasm was 80 mm deep and 400 mm wide. When the rover detected a small gap with the frontal undercarriage sensor, it reduced its speed to ensure it had sufficient time to either detect whether it was able or not to overcome the chasm without depositing material. Once the rover detected that the chasm was too long by using both undercarriage sensors, it started its gap filling procedure. The material depositing system estimated the amount of material to be deposited from the knowledge of the depth of the chasm (measured by sensors), performed the deposit and then waited for this to expand and solidify. The rover successfully filled the chasm and traversed the gap as shown in FIG. 10.

[0208] Total time for this experiment time was 5 minutes and 50 seconds.

[0209] FIG. 10.1: The vehicle 2 approaches the obstacle O (i.e. the chasm), senses the obstacle O and stops.

[0210] FIG. 10.2: The vehicle 2 moves away from the obstacle O and turns around, such that the set of deposition nozzles 500 face the object O.

[0211] FIG. 10.3: The vehicle 2 deposits the PU foam F into the obstacle O.

[0212] FIG. 10.4: The deposited PU foams, filling the chasm, and cures.

[0213] FIG. 10.5: The vehicle 2 moves over the foam F, traversing the obstacle O.

[0214] FIG. 10.6: The vehicle 2 has traversed the obstacle O.

[0215] Blending Chamber

[0216] FIG. 11A is a CAD perspective view and FIG. 11B is a schematic cross-sectional view of a blending chamber 300 of the deposition apparatus 20 of the vehicle 2 of FIGS. 4A and 4B. In this example, the blending chamber 20 comprises a set of spherical chambers 310, including a first chamber 310A and a second chamber 310B , both having internal radii of 6 mm, for example a pair thereof of mutually interconnecting chambers, particularly indirectly interconnecting via an interconnecting passageway 320. In this example, the set of inlet passageways 400 (400A, 400B, 400C) have an internal diameter of 2 mm and are fluidically coupled to the first chamber 310A. In this example, the set of outlet passageways 600 (600A, 600B) have an internal diameter of 2 mm and are fluidically coupled to the second chamber 310B. In this example, the interconnecting passageway 320 has an internal diameter of 4 mm, smaller than a diameter of the first chamber 310A and the second chamber 310B. In this example, the blending chamber 20 does not comprise a static mixer, for example a helical static mixer or a plate-type static mixer. In this example, the blending chamber 20 comprises smooth internal walls, without any protuberances therefrom.

[0217] Deposition Nozzle

[0218] FIG. 12 is a photograph (perspective view) of a deposition nozzle of the deposition apparatus of the vehicle of FIGS. 4A and 4B. The deposition nozzle is a static mixing nozzle (MA6.3-21S, Adhesive Dispensing Ltd, UK). In more detail, the deposition nozzle is a bayonet inlet, helical static mixer nozzle, conventionally for 50 ml and 75 ml dual component cartridges. Stepped outlet that can be cut back to increase orifice size and increase flow rates. These mixer nozzles are suitable for all two-component materials. They have white elements and are constructed of high grade polypropylene. High quality mixer nozzles for use with twin cartridges. 6.3 mm ID×21 mixing elements. Use with 50 ml 1:1 and 2:1 ratio bayonet style dual cartridges. Part ID: MA6.3-215. Material: Polypropylene. Colour: Natural Outer, White Elements. Inner Diameter: 6.3 mm. Outer Diameter: 9 mm. Length: 153 mm. Tip Outlet: 1.5 mm. Elements: 21. Retained Volume: 3.6 ml. Details: Industrial grade, Silicone Free.

[0219] Summary of Experimental Results

[0220] A summary of the experimental results is reported in Table 3, showing that the proposed PU foam depositing system enables the rover to overcome obstacles which were previously insurmountable. In all cases, the volumetric expansion ratio was between 29× and 32×, showing the robust control over the mixing process and, hence, the final mechanical properties of the foam. These values also prove that conservative estimates were attained during characterisation for expansion, this was ascertained to be due to free rise expansion being larger than controlled expansion in a measuring beaker. Survival rates of trapped victims within collapsed buildings depends entirely on the circumstance, with major trauma and suffocation typically killing within hours. A depositing system that can enable a robotic platform to access these areas within minutes is suitable.

TABLE-US-00003 TABLE 3 Summary of experimental results, where H = Height, D = Depth, L = Length and Vol = Volume. Test One Test Two Test Three Type Small Frontal Large Frontal Chasm Dimensions H: 60 H:130 D × L: 100 × 200 (mm) Deposit Vol 2000 5000 4000 (cm.sup.3) PU used 63 170 126 Run time 6 mins 42 secs 13 mins 42 secs 5 mins 50 secs

[0221] Method of Controlling a Vehicle

[0222] FIG. 13 schematically depicts a method of controlling a vehicle to deposit a foam comprising a polymeric composition according to an exemplary embodiment; and

[0223] At S1301, a first component and a second component of the polymeric composition are blended, using a blending chamber, to provide a precursor of the polymeric composition.

[0224] At S1302, the foam is generated, at least in part, by mixing, using a static mixer included in a first deposition nozzle, the precursor.

[0225] At S1303, the foam is deposited, at least in part, via the first deposition nozzle. The method may comprise any of the steps described herein.

[0226] Method of Depositing a Foam

[0227] FIG. 14 schematically depicts a method of depositing a foam comprising a polymeric composition according to an exemplary embodiment.

[0228] At S1401, a first component and a second component of the polymeric composition are blended, using a blending chamber, to provide a precursor of the polymeric composition.

[0229] At S1402, the foam is generated, at least in part, by mixing, using a static mixer included in a first deposition nozzle, the precursor.

[0230] At S1403, the foam is deposited, at least in part, via the first deposition nozzle.

[0231] The method may comprise any of the steps described herein.

[0232] Although a preferred embodiment has been shown and described, it will be appreciated by those skilled in the art that various changes and modifications might be made without departing from the scope of the invention, as defined in the appended claims and as described above. For example, while the deposition apparatus is described included in the vehicle, the skilled person would understand that the deposition apparatus may be provided separately from the vehicle and/or the controller.

SUMMARY

[0233] In summary, the invention provides a vehicle, a method of controlling a vehicle, an apparatus for depositing a foam, a method of depositing a foam and use of a blending chamber.

[0234] One of the most difficult challenges faced by ground robots operating in the aftermath of a disaster is the presence of uneven and unstable terrains; in these environments traditional locomotive systems struggle. In this work, a polyurethane foam depositing system is proposed to enable ground robots to overcome obstacles and navigate challenging substrates with relative ease. The proposed system is inexpensive, can be added onto existing platforms and enables autonomy via simple control systems. The final mechanical properties of the foam can be tuned in real-time and on board to adapt to different situational requirements. Four deposit foam types have been fully characterized, with volumetric expansion ratios ranging from 20× to 33×, compressive strengths from 0.16 MPa to 2 MPa and full expansion and set times below 6 minutes in all cases. To show that real-time operations are possible, the system has been implemented on a two-tracked rover which was then able to accurately control the amount of deposited foam to form structures such as single and multilayered ramps and blocks. Thanks to this, the vehicle was able to autonomously overcome large objects and chasms that would have otherwise prevented operation.

[0235] In more detail, an inexpensive and easy-to-use apparatus for depositing a foam is described. The apparatus is designed as an independent module for existing robotic platforms to expand their capabilities. Thanks to its design, the apparatus can be utilised without complicated control algorithms to allow ground vehicles to autonomously overcome obstacles. This allows complete control over the deposited material: the PU foams expansion ratio and final compressive strength can be tuned autonomously according to the situational requirement. The integrated solvent flush system allows the long term use of the apparatus without blockage, a typical drawback of existing platforms. Initial tests show that the vehicle provides a significant improvement of the capability of ground vehicles to move on uneven terrains. The apparatus then removes the main obstacle for using ground robots in disaster scenarios.

[0236] Notes

[0237] Attention is directed to all papers and documents which are filed concurrently with or previous to this specification in connection with this application and which are open to public inspection with this specification, and the contents of all such papers and documents are incorporated herein by reference.

[0238] All of the features disclosed in this specification (including any accompanying claims and drawings), and/or all of the steps of any method or process so disclosed, may be combined in any combination, except combinations where at most some of such features and/or steps are mutually exclusive.

[0239] Each feature disclosed in this specification (including any accompanying claims, and drawings) may be replaced by alternative features serving the same, equivalent or similar purpose, unless expressly stated otherwise. Thus, unless expressly stated otherwise, each feature disclosed is one example only of a generic series of equivalent or similar features.

[0240] The invention is not restricted to the details of the foregoing embodiment(s). The invention extends to any novel one, or any novel combination, of the features disclosed in this specification (including any accompanying claims and drawings), or to any novel one, or any novel combination, of the steps of any method or process so disclosed.