ITFI20130101A1 - DEVICE FOR AUTONOMOUS AND NON-DESTRUCTIVE ENVIRONMENTAL PENETRATION - Google Patents

Description

DEVICE FOR THE AUTONOMOUS AND NON-DESTRUCTIVE PENETRATION OF

ENVIRONMENTS

DESCRIPTION

The present invention relates to the field of robotic devices for autonomous and non-destructive penetration and movement within structured but above all unstructured environments such as soil, debris, organic tissues, etc. More specifically, it relates to a penetration device continuous three-dimensional track suitable to be used for exploration, monitoring, diagnostic purposes.

Drilling and excavation by means of appropriate mechanisms are the traditional techniques to access the subsoil for different applications (research of water and fossil fuels, geological studies, etc.) and with different objectives (collection or deposition of materials, simple opening of a passage towards the surface). Numerous mechanical techniques are used for these purposes: quasi-static thrust, rotation, percussion, vibration, and combinations of these techniques. Techniques of a non-mechanical nature have also been proposed or envisaged, such as thermal systems (for example in the case of penetration into ice), sound waves or ultrasounds or lasers. However, these are systems that at least partially alter or even destroy the substrate and may require problematic energy consumption.

Remaining, as far as is of interest here, in the field of mechanical solutions, the equipping of penetration / drilling systems with robotic devices can obviously allow automatic exploration of the subsoil (or in any case sub-surface), with evidently profitable uses in inaccessible areas, and taking this into account, the research focused on the objectives of greater efficiency of the excavation and sampling methods and on the size reduction of the device. However, conventional penetration techniques require high axial thrusts (i.e. along the axis of penetration), provided by the weight of the device itself, and for this reason the masses cannot be reduced beyond a certain limit, indeed masses must sometimes be provided additional or other anchoring systems where the intrinsic mass is not sufficient.

To overcome this situation, systems have been proposed in which an anchorage to the substrate to be perforated provides the axial force of penetration, in particular where the force of gravity is reduced. A robotic drilling system proposed in (Liu Y. et al., "Mechanical Design and Modeling of a Robotic Planetary Drilling System," In Proc. Of IDETC / CIE 2005 ASME 2006 Int. Design Eng. Tech. Conf. & Comp. and Inf. in Eng. Con., Philadelphia, 2005) and the biomimetic robot inspired by a worm in (Kubota et al., "Earth-worm typed Drilling robot for subsurface planetary exploration," IEEE Int. Conf. on Robotics and Biomimetic (ROBIO), Sanya, 2007, pp. 1394-1399) work as â € œclimbersâ € devices equipped with a perforation module at the tip. After having made a beginning of the tunnel, they are attached to the walls of the same to obtain the axial force necessary for drilling and advancing. Various adhesion systems (between device and tunnel walls) can offer a satisfactory response, including the use of spiked â € œfingersâ € as in Parness A., "Anchoring foot mechanisms for sampling and mobility in microgravity," IEEE Int. Conf. On Robotics and Automation (ICRA), Shanghai, 2011, pp. 6596-6599.

In addressing the problems posed by reduced gravity, bio-inspired robots have also been proposed in which, thanks to particular geometric characteristics, the interaction between the penetration mechanism and the medium in which the penetration occurs prevents backward movement and provides an anchor. appropriate. An example of this kind, inspired by the technique of drilling the ovipositor organ of certain hymenoptera, is described in Gao Y. et al., "Deployable wood wasp drill for planetary subsurface sampling," IEEE Aerospace Conf., Big Sky, 2005, p.8.

Adhesion systems already proposed include continuous track systems or tracked wheels, such as for example in devices for ascending and exploring the interior of pipelines (Kim J. H. Et al. "FAMPER: A fully autonomous mobile robot for pipeline exploration , "IEEE Int. Conf. On Industrial Technology (ICIT), Vina del Mar, 2010, pp.

517-523.) Or life-saving devices. The latter include, for example, snake robots such as that in Borenstein J. Et al., "The OmniTread OT-4 Serpentine Robot for Emergencies and Hazardous Environments," International Joint Topical Meeting: â € œSharing Solutions for Emergencies and Hazardous Environments, â € February 12-15, 2006, pp. 1-8. This type of robot provides crawler systems with an overall three-dimensional development, and in particular cylindrical, obtained however by adding and combining a plurality of tracks, each single and substantially linear.

Obviously, and more generally, it is possible to equip a single track with directionality due to internal deformability or flexibility (as for example in US2009 / 0025988) or according to the traditional technique of tracked means of locomotion, it is also possible to provide the robot of a double track (see for example the robot in US2004 / 0216932), so by varying the speed of each track it is possible to vary the direction of motion. In this way, greater maneuverability is achieved in unstructured environments and the ability to circumvent obstacles.

The limit of all this type of device basically lies in two aspects. First of all, they have an open structure that makes penetration into granular substrates problematic, as the granular particles interfere with the reciprocally moving parts, accessible from the outside, causing malfunctions or jams. Second, the relative movement between the device and the environment to be penetrated reduces the efficiency of the penetration and alters the substrate.

The use of sealing means can tackle the first aspect, but with structural complications and however introducing problems of reliability. And in any case the combination of moving components (the tracks) and fixed components (the seals) involves two different dynamic behaviors in terms of relative speed with respect to the ground or in any case to the particles of the medium or substrate to be penetrated. In particular, during penetration the relative speed on the track is, or should ideally be, zero, while the fixed components of the sealing system move in contact with the external particles at the same penetration speed, with the inevitable and unwanted friction that they hinder the penetration itself. Therefore, the parts of the device not covered by tracks are in contact with the environment to be penetrated and move with respect to it (unlike the track, which remains integral with the environment). Consequently, the propulsive effect of the track is lacking in these areas. Furthermore, friction causes energy dissipation and decreases penetration efficiency.

Finally, the mechanisms of penetration of plant roots have already been studied, in order to obtain useful information for the development of robotic devices (Bar-Cohen Y. et al., Drilling in Extreme Environments: Penetration and Sampling on Earth and other Planets . Wheinheim: WILEY-VCH Verlag CmbM & Co. KGaA, 2009; Mazzolai et al., Â € œA Miniaturized Mechatronic System Inspired by Plant Roots for Soil Explorationâ €, Trans. On Mechatronics, IEEE / ASME, vol. 16, no. 2, pp. 201 - 212, 2011).

Considering this state of the art, the purpose of the present invention is to provide a self-penetrating robotic device which meets the requirements of lightness and construction simplicity using a generically continuous track system that ensures a completely firm anchorage with the ground or other generic substrate in which the penetration takes place, with consequent effectiveness of the latter, while preventing the interference of particles of the substrate between fixed parts and parts in relative motion (at the penetration speed), always with respect to the substrate, and minimizing the frictions that they oppose advancement.

This and other objects are achieved by the device for the autonomous and non-destructive penetration of environments according to the present invention, the essential characteristics of which are defined in the first of the annexed claims.

Further important features are contained in the dependent claims. The characteristics and advantages of the device for the autonomous and non-destructive penetration of environments according to the present invention will become clearer from the following description of its embodiments made by way of non-limiting example with reference to the attached drawings in which:

Figure 1 is a schematic axonometric view of the device according to the invention in a first embodiment;

- figure 2 is a schematic axial sectional view of the device of figure 1 when entering an unstructured environment (ground);

- Figures 3 and 4 are partial representations in axial section of the device in two successive phases of penetration, to better clarify the functional concept underlying the invention; And

Figure 5 schematically shows a partially broken axonometric view of a second embodiment of the device according to the invention.

With reference to Figures 1 to 4, the device according to the invention comprises in a first embodiment a rigid tubular body 1, elongated along a straight linear axis X and preferably (but not necessarily) circular in cross section. The body 1 has a first end 1a, or tip end as it corresponds to the front of advancement and penetration into the substrate, and a second end 1b, or tail end with respect to the advancement. The tail end 1b is provided with a bracket 3 which extends radially and integrally from the body 1, and supports an actuator 4 which will be discussed later. An internal axial channel 2 of the tubular body 1 is defined by an internal surface 1c, and opens on the tip end 1a, while the external surface is indicated with 1d.

Associated with the body 1 is a three-dimensional track 5, in the form of a sock made of textile material (or in any case with a non-textile structure but in any case foldable and substantially inextensible at least in the axial direction X) also configured in tubular form. The material in which the track 5 is made can be, for example, a sturdy nylon fabric or other fiber capable of ensuring characteristics of pliability and inextensibility.

The tubular track, taking as reference an inactive starting configuration of the device, is arranged for the most part coaxially inside the channel 2, to cover the internal surface 1c and in a non-extended position, i.e. contracted and folded back on itself in so as to occupy a significantly lower axial distance than the theoretical one in fully extended position. An internal end of the track 5, indicated by 5a, is therefore inside the body 1, displaced towards the tail end 1b. However, the track also extends beyond the tip end 1a of the body 1, and folded on the external surface 1d covers a modest part of this, up to an external end 5b which is integrally joined to a rigid collar 6 which a in turn it evolves annularly around the body 1 and is able to slide axially without significant friction along it.

From the collar 6, axially towards the tail end 1b and the bracket 3, a cable 7 which attaches to the aforementioned actuator 4. More precisely, the actuator 4 provides a motor 8 (and relative supply battery) which rotates a pulley 9 around which the cable 7 is wound, so that the rotation of the pulley puts the cable in traction, draws the outer end 5b of the track 5 with the collar 6 towards the other, and therefore causes distension and, therefore ¬ say, the unwinding of the track itself from the inside to the outside of the body 1.

The inner end 5a of the track is in turn preferably provided with a thread-like tie rod 10 which, passing through a hole 1e obtained on the body 1 towards the tail end 1b, is accessible through its end 10a (equipped of a handle and non-return knob) on the outside of the body itself and can be used to bring the track back into the channel 2 and facilitate the resumption of the starting position mentioned above.

The exposed face of the track 5, the one in truth properly external in the portion lying on the outside of the body 1 but turned inwards when the track is inside the channel 2), is equipped with a diffuse and regular distribution of growths 11 (not represented in figure 1) able to stick stably in the substrate to be penetrated. These growths advantageously have the form of artificial bristles (average diameter of 1.5 ± 0.6 mm and length of 5 ± 1 mm made for example with point-like applications of a thermosetting resin.

The device according to the invention, in the embodiment described above, works in the following way. The body is presented to the substrate to be penetrated, with a modest manual insertion, allowing the bristles 11 to anchor on the substrate itself. At this point, the actuator 4 comes into operation which puts the cable 7 in traction, traction which discharges axially on the collar 6 and on the bracket 3.

Since the relative movement between the track and the substrate is prevented by the static friction resulting from the anchoring of the bristles 11, the aforementioned traction results in a thrust of penetration on the bracket and consequently on the body 1, with consequent progressive exit of the track from the channel 2 (figure 4) and increase of the surface gripping the substrate, through the bristles 11. It can be seen from figure 4 how the reciprocal position of the collar 6 and of the surface of the substrate indicated with S is unchanged with respect to the starting condition, but the body 1 is more penetrated and at the same time a greater portion of the track is extended on the external surface 1d and anchored on the substrate. This driving action can evidently progress up to the complete penetration of the body 1.

The principle of continuous three-dimensional crawler locomotion described above can find different embodiments, first of all as regards the system for implementing the relative movement between crawler 5 and body 1. As well as obviously possible variants of the active transmission on the tail (alternatives to pulley / cable, for example rack and pinion and generally gear systems), a more marked variant provides for an actuation on the tip end of body 1. This variant can also be used with a rigid body 1 like the one just described, or , as in the second embodiment schematically illustrated in Figure 5, to which reference is made below, in the context of a flexible body 101.

The flexibility of the body 101 is in this case determined by a plurality of joints 112 which connect linear cylindrical segments 113, all always according to an overall tubular configuration which determines, as in the previous example, an internal channel 102 in which it is housed the track 105. The transmission of motion relative to the track is determined by a system of wheels 107 rotatably mounted on the tip end 101a, with tangential relationship with respect to the external surface 101d, and engaging by friction (or other engagement systems such as toothing ) on the inner face of the sock / track. The wheels 107 are driven, through a transmission of obvious nature, for example toothed, by actuators 108 integrated in the body. Track movement can also be assisted by other active wheels along the body (not shown). Furthermore, the joints 112 can be actively controlled, also in this case with constructive expedients in and of themselves within the reach of the person skilled in the art, in order to achieve an adaptation of the shape and a directional control of the locomotion.

The rigid cylindrical body is ultimately more suitable for applications such as linear penetration, in particular of the soil, while the flexible shape is more suitable for applications such as the exploration of environments in which it is necessary to circumvent obstacles.

It is therefore evident from the foregoing that the invention provides a device of unprecedented conception, which achieves the intended purposes thanks to the continuous three-dimensional track which simply ensures effective penetration without relative motion between the substrate and the penetrating body (protected by the same track which instead it is stationary with respect to the substrate) and, again for the same protective effect, preventing the interference of particles of the substrate between fixed and moving parts (with respect to the substrate itself). Penetration is non-destructive and is counteracted by negligible friction (relative between the track and the body).

The invention is thus able to open numerous and important outlets both relating to the penetration / exploration of structured environments such as pipelines and to that of unstructured environments such as soil, debris, caves, orifices, soft tissues, all both for purposes exploratory and diagnostic, in environments with reduced gravity or in conditions of normal severity.

For these purposes, the device can be equipped with sensors or communication modules, arranged on the body or even on the track itself. The hollow structure can also be exploited for a transport function (medicines, video cameras, cables or other components). More generally, it can be used as a propulsive module for more complex robotic structures that include other equipment or tools, for example sampling means.

The present invention has been described up to now with reference to its preferred embodiments. It should be understood that there may exist other embodiments which pertain to the same inventive core, all falling within the scope of the claims set out below.

Claims (16)

CLAIMS 1. A self-penetrating device comprising: a tubular body (1) elongated in an axial direction starting from a tip end (1a), defining an external surface (1d) and an axial channel (2) which opens on said end peak; a three-dimensional track (5) of tubular shape, collapsible and substantially inextensible structure at least in said axial direction, stored within said channel (2) but coming out of said tip end (1a) to extend along at least one axial segment of said external surface ( 1d), the track having an exposed face which is external on the external surface (1d) of the body (1) and turned towards the inside of the body in the track part within said channel (2), a distribution being obtained on said exposed face diffusion of outgrowths (11) suitable for anchoring to a substrate to be penetrated; and actuator means (4) arranged on said body (1) and operating on said track (5) to actuate its progressive exit from said channel (2) and relative sliding on said external surface (1d) away from said tip end (1a). The device according to claim 1, wherein said actuator means (4) are associated with a tail end (1b) of said body (1) axially opposite to said tip end (1a). The device according to claim 2, wherein said actuator means (4) are connected for actuation by means of transmission means (8, 7) with an outer end (5b) of said track arranged on said outer surface (1d) of said body (1). The device according to claim 3, wherein said outer end (5b) of said track (5) is integral with an annular collar (6) which evolves around said outer surface (1d) and slides axially along it. The device according to claim 3, wherein said transmission means comprise a pulley (9) driven by a motor (8) of said actuator means (4), and a cable (7) suitable for winding on said pulley and connected to said collar (6). The device according to any one of claims 2 to 5, wherein said actuator means are mounted on a bracket (3) projecting radially from said head end (1b) of said body. The device according to any one of the preceding claims, wherein said body (1) is a rigid body with a straight linear axis (X). The device according to claim 1, wherein said actuator means are associated with said tip end (101a). The device according to claim 8, wherein said actuator means (108) are integrated in said body and drive a plurality of wheels (107) rotatably mounted on said tip end (101a), with tangential relationship with respect to the external surface ( 101d), and engaging with said track (105). The device according to claim 8 or 9, wherein said body (1) is a rigid body with a straight linear axis (X). The device according to claim 8 or 9, wherein said body is a flexible body (101) comprising a plurality of joints (112) which connect linear tubular segments (113). The device according to claim 11, wherein said joints (112) are actively controlled. The device according to any one of the preceding claims, wherein said actuator means further comprise active wheels arranged along said body and engaging by friction with said track (5, 105). 14. The device according to any one of the preceding claims, wherein said track is made of textile material, for example nylon fabric. The device according to any one of the preceding claims, in which said outgrowths (11) are artificial bristles with an average diameter of between 0.9 and 2.1 mm and a length of between 4 and 6 mm. 16. The device according to claim 15, wherein said growths are made with point-like applications of a thermosetting resin.