DE19855175C1 - Guide mechanism for high-pressure water jet for cleaning inside of pipeline has tripod arrangement of actuators mounted on pig inside pipe - Google Patents

Abstract

The mounting device or pig (1) fits inside the pipeline and may be moved along it. The pig has a flat front (1a) face with three swivels carrying e.g. hydraulic piston and cylinder units (2) whose other ends are connected together (4) so as to allow movement. The water spray nozzle is attached to this point.

Description

The invention relates to a device for Management of a blasting tool, for example one High pressure water nozzle for cleaning pipes. The device according to the invention is generally in the field assign the robot kinematics, where it u. a. to the exact positioning and movement of tools.

Blasting tools such as high pressure water jet and Abrasive water jet tools are particularly suitable Way of removing materials. The ones for generation of the high pressure required rigid hose conn bonds and high forces of jet pressure as well as rota toric forces of the nozzle, however, make it difficult to position these tools in confined spaces kidneys. Piping systems are an example as mentioned sewers. Water is suitable here through his neutral behavior and the favorable property shaft of automatic overburden removal in special way as a cutting medium.

It is a tool guidance system in the real sense of a manipulator. Leave this divided into serial and parallel structures divorce.

With the serial manipulators one can ortho gonal systems with trivial mathematical connection between axis positions and room position to be approached and non-orthogonal systems, with to  Part of quite complex mathematical mapping regulations.

The simplest orthogonal kinematic structure is the Cartesian structure with three translational ones Degrees of freedom. In addition, there exist in the Mathematics known another ten orthogonal systems in three-dimensional space, which is based on mathematical simple way the relation between axis positions of the Drives and the spatial coordinate system, also "world coordinate system ", in mathematical terms trivial case, axis and world system are identical. The Transformation of coordinate representations between the orthogonal systems is simple and unique solvable.

For reasons of the required installation space and The high demands on rigidity can be met orthogonal systems, however, in many cases, as in the preferred field of application described here High pressure blasting tools in pipe systems, not use.

Serial structures with an open kine matic chain have an unfavorable ratio between manipulator mass and payload or tool force absorption. Also the collision room of the manipulator component is unfavorable in confined work spaces.

For the use of a blasting tool within a tubular work space is for movement the beam guidance changes the orientation of the Tools necessary. This requires all solutions an axis of rotation with an open kinematic chain.

This, however, will be rotary unions for Supply lines necessary, which are difficult to are realized. Thus, the non-ortho  gonal kinematic structures for the use of Little high pressure blasting tools in pipe systems suitable.

The parallel structures include tripods and Hexapods. These have three or six free degrees of safety. Also intermediate structures between hexapods and tripods are known.

The basics of one on a hexapod based manipulator are for example in C. Gosselin, "Determination of Workspace of 6 DOF Parallel Manipulators ", in American Society of Mechanical Engineers, Journal of Mechanical Design / publ. quarterly by the American Society of Mechanical Engineers - New York, NY: ASME, 112, pp. 331-336, 1990, described.

Examples of the use of a tripod are in K.-M. Lee et al., "Kinematic Analysis of a Three- Degrees-of-Freedom In-Parallel Actuated Manipulator ", IEEE Journal of Robotics and Automation, Vol. 4, No. 3, p. 354-360, June 1988.

Also with the hexapods and Tripods are the high forces of jet pressure as well rotational forces of the nozzle, however, only via ent to cope with appropriately dimensioned drives that difficult to use in confined spaces.

The object of the present invention is therein, a device for guiding jet work testify to indicate that the disadvantages above are not has and can be used advantageously in confined spaces is.  

The object is achieved with the device according to claim 1 solved. Advantageous embodiments of the device are the subject of the subclaims.

The device according to the invention enables in advantageously the guidance of a blasting tool within confined work spaces. The blasting tool has an outlet opening for a jet on that along a first axis of the tool exit. The device has a carrier element as well a first and second translatory drive axle on, which are connected to the support element and by one can be controlled independently. The tool or a holder for the tool is on a first Point in the area of the first axis with the beam element connected that the outlet opening of the Tool on a section of a (virtual) Spherical surface around the first point as the center of the Ball can be moved. The connection can for example via a swivel joint. The first and second translatory drive axle are in a constant distance from the first point directly or via intermediate elements with the tool or connected to the bracket so that it is at the appropriate Drive movement the outlet opening of the tool to any position within the section can move the spherical surface. The area of Tool or the bracket between the first point and the connection points with the drive axles thus rigid, d. H. unchangeable in length.  

The device according to the invention is one of the parallel structures and is based on the structure of the tripod. In contrast to tripods, however, the device has only two degrees of freedom, which, as explained later in connection with FIG. 6, enable the intended use.

The on the device or the tool system acting forces are mainly on the beam axis (first axis). Through the fixation described of the tool on the carrier element, these forces are applied the first point, hereinafter referred to as the fixed point, transfer. The fixed point is preferred wise on the first axis, but there is also one slight deviation from this axis can be tolerated without to change the balance of power significantly. Becomes the tool, as in the present device any other point, so the resulting forces on the additional support point in the amount less than at the fixed point. Through the implementation according to the invention it is therefore possible in a simple manner, almost the total tool forces caused by the beam to transfer to the fixed point. The additional sub base is thereby almost power and moment free. All not caused by the beam Forces such as B. gravitational forces are of this Except for consideration.

By fixing a tool point the supply of lines is also easier to the blasting tool considerably, since tool points are close the fixed point is not subject to rotation. Will the  Tool supply line through the fixed point or placed in its immediate vicinity, it plays Stiffness of this supply line one under ordered role. Because the tool system is not about its Longitudinal axis rotates are not rotary unions required. These two design simplifications are crucial for the use of pressurized water tools.

Tool forces are transferred via the fixed point. Drives and tool guidance can therefore be dimensioned accordingly weak.

The invention enables a blasting tool to run on a spherical path and with the Energy beam of the tool directly accessible space points without retroactive effect on the orientation of the To edit blasting tool. The tool and all Components can be inside a tube shaped cylinders are located and reach from one appropriate distance from the tool system all Space points within the tube. The installation space of the Drive axes of the tool guide is also in a favorable angular range, so that the Device according to the invention for the management of Blasting tools in pipe systems in an ideal way is suitable.

The solution shown is based on the modifi cation of a tripodial system, as shown in Fig. 1.

The invention is derived from the Hexapods, such as those in the introductory part  published by C. Gosselin is.

The "mobility" of a hexapod is like this that in a given work space, the Spatial points in the three position coordinates with three Orientation coordinates can be achieved and thus the System has six degrees of freedom.

By reducing the drive rods to three, the number of degrees of freedom is also reduced to three. With a suitable choice, only the three orientations are lost. The three degrees of freedom of the spatial coordinates remain accessible. This kinematics represents the tripod as shown in FIG. 1.

In the structure according to the invention, hereinafter referred to as the dipode, one of the drive axles or rods of the tripod has a fixed length (cf. FIG. 2).

In an advantageous embodiment, the first and second drive axle via a rigid one Intermediate element of constant length with the tool or connected to the bracket. The intermediate elements are over Joints connected to the drive axles. In this In this case, the drive axles can be positively driven. H. in their orientation relative to the support element lie. With this arrangement, a virtual Tripod between the drive axles and the first Axis of the tool formed.

The connection point of the intermediate elements with the Tool is preferably closer to the exit opening as at the fixed point.  

Of course, only one of the Drive axles via an intermediate element and the other be directly connected to the tool. In this case the relative drive axis can be relative in orientation to the carrier element.

The invention presented is a tool guidance system that enables in tubular or narrow working spaces such as high pressure water jets, and with the beam generated by the tool a certain point within the work space head for. The forces and forces generated by the tool Moments are minimal on the guidance system transfer, resulting in small drive power and low demands on the rigidity of the guides or drive axles. The area of movement of the Tool guidance allows simple sealing measures.

The for the device according to the invention suitable tool systems create one on one Semi-straight "working beam". That beam is usually rotationally symmetrical, starts on Exit point or the outlet opening of the tool and sits straight or over a working distance almost straight away. The working beam can do this from continuous mass flow such. B. at high pressure Water jet tools, continuous electromag netic alternating fields such. B. with a laser, or a discrete mass flow such. B. at by blowing charge accelerated bulk particles such as projectiles consist.  

Of course, the design of the Device according to the invention also for microsystems suitable, where the workspace, for example, a Represents bloodstream.

In the following, the invention is explained again using exemplary embodiments in conjunction with the figures, the representation of FIGS. 1 to 6 taking place in accordance with VDI 2861. Show here

Fig. 1 shows schematically a model of a tripod according to the prior art;

2 schematically shows as a first embodiment, a basic model for the inventive device.

Fig. 3 shows a possible realization of the basic model of Fig. 2;

Fig. 4 as a second embodiment of the present invention a modification of the basic model of Fig. 2;

Fig. 5 is a schematic representation of a robot unit in a tube based on the embodiment of the device according to the invention according to Fig. 4;

Fig. 6 is a side view of a working space in a tube for illustrating the achievable with the device edit points; and

Fig. 7 shows an example of the application of the device according to the invention in a pipe system.

Fig. 1 shows schematically a model of a tripod, as it is known in principle from the prior art. The tripode has three mutually independent drive axes 2 , which are mounted in the construction level 1 a of a carrier 1 . The three axes converge at so-called central point 4 . In known systems of the prior art, the three axes do not converge at exactly one point, but are connected to the edge areas of a platform on which tools can be attached. The three axes 2 each represent translatory drives with which, with suitable control, the orientation of the platform relative to building level 1 a can be changed.

In FIG. 2, a basic model for the inventive device is illustrated according to a first embodiment by way of example. In this structure according to the invention in the form of the dipode, one of the axes shown in FIG. 1 has a fixed length. The device according to the invention thus has only the two translational drive axles 2 a and 2 b. The third axis 3 corresponds to the beam axis of the tool and is invariable in length between the attachment point (fixed point 5 ) on the building level 1 a and the central point 4 . As a result, the central point - and also each further point of the beam axis between the central point and the fixed point - can only move at a constant distance from the fixed point 5 , i. h on a sphere with the fixed point 5 as the center of the sphere. By suitably controlling the two drive axes 2 a, 2 b, a point of the beam axis can be positioned as desired within a section of the respective spherical surface. Of course, corresponding joints must be provided for this at the central point 4 and the connection points 6 a, 6 b of the drive axles to the building level 1 a, which enable the mobility of the axles 2 a, 2 b.

Fig. 3 shows an example of a possible implementation of the basic model of Fig. 2. In this example, a high-pressure water jet nozzle 7 is shown with an outlet opening 8 for the jet. The nozzle is connected to the carrier 1 via a base-side axle joint at the fixed point 5 . The longitudinal axis 3 of the nozzle, which at the same time corresponds to the jet axis, passes through the fixed point 5 . A hint is also a rigid supply line 9 for the nozzle Darge, which is near the fixed point. The two drive axles 2 a, 2 b are designed as variable-length drive rods which converge at the support point 4 and are connected to the nozzle 7 . In this example, the base-side axis joint of the fixed axis 3 of the dipod becomes the fixed point 5 of the tool and the central point of the dipod becomes the additional support point 4 of the tool. The two drive axles 2 a, 2 b form a tripod with the tool 7 .

The central point or support point needs do not lie on the beam axis.

Due to the fixation of the water jet nozzle 7 on the carrier 1 , the direction of force, which is caused by the jet of the tool, is severely restricted in its direction. The force transmission point corresponds to the fixed point 5 . In this way, the moments acting on the overall system can be limited in a simple manner.

FIG. 4 shows, as a second example, an embodiment of the device according to the invention in which the basic model of FIG. 2 is modified. In this example, the two drive axles 2 a, 2 b are fixed in their orientation relative to the carrier element, for example via corresponding guide elements 12 . At their end points, the drive axles each carry a pivot bearing 10 a, 10 b equivalent to a ball joint. At this camp a rod 11 a, 11 b fixed length is attached, the tool ends in the central point of the dipod or in the support point 4 of the tool. By shifting the two axes 2 a, 2 b along their specified orientation, the angle of the rods to the drive axes changes. The uppermost point M of the spatial position achievable with the tool axis 3 (cf. FIG. 5) is reached when both rods are perpendicular to their respective drive axes.

FIG. 5 schematically shows the representation of a robot unit in a tube based on the embodiment of the device according to the invention according to FIG. 4. The same reference numerals were used for the same elements as in FIG. 4. The robot unit consisting of the carrier element 1 , the drive axes 2 a, 2 b, the rods 11 a, 11 b and the tool system (beam axis 3 ) is located in a tube 13 , the inner surface of which is to be machined. The movement space of the system is spherical, as indicated by the broken line in the figure. The working space of the dipode, which is illustrated by the cone section 14 , is also determined by a suitable choice of the rod length.

A detailed view of a working space of the device according to the invention is shown in Fig. 6 Darge. This figure shows the side view of the working space in a tube 13 to illustrate the machining points achievable with the device. The device according to the invention is shown here only in a highly simplified manner with carrier element 1 and tool or beam axis 3 (without drive axes).

The tool systems used for the device according to the invention generate a "working beam" lying on a semi-straight line. This beam begins at the exit point 8 of the tool and continues in a straight line or almost straight line over a working distance.

The intersection of the semi-straight line with an obstacle in space represents the point of intervention of the blasting tool. This point is referred to in the following as TCP, ie tool center point. The semi-straight line is the energy beam 15 .

If the beam-generating tool or its holder is fixed at a point 5 , as in the present figure according to the invention, and if this fixed point is close to or on the axis of the energy beam generated, then any spatial point in the working area of the beam tool can be reached. The angle of incidence of the beam on a processing surface (here the tube wall) is fixed for each point of impact and cannot be influenced. In addition, only the first obstacle 16 on the path of the energy beam is reached, points behind it are considered unreachable.

The working space that can be reached with the system extends from that between the two lines 17 and 18 shown in the figure, the latter depending on the range of the beam. The former depends on the area in which the drive axes can move the tool axis 3 .

By fixing the tool, the exit point of the energy beam describes a sphere 19 with a center around the fixed point. Every point in space, which represents an obstacle for the energy beam and is closest to the tool exit point 8 on the half straight, fixed point obstacle, can be mapped by its projection onto this sphere. The illustration is therefore clear. That is, a spatial point described according to the above requirements can be represented by two independent coordinates that describe a point on the sphere. This results in the requirement of two degrees of freedom in the tool guide.

The above, made for the space point Restrictions apply generally to editing points of blasting tools and are therefore not a disadvantage of the illustrated invention compared to the prior art Technology.

The overall system of the device according to the invention can be unproblematically by a flexible Seal the hood system. This means that IP68 (degree of protection; IP = "International Protection") without much effort reached so that there is a waterproof system. On  Jamming of the hood system is due to the spherical operation with little effort avoidable.

Fig. 7 shows an example of an application of the device according to the invention in a pipe system.

A caterpillar drive unit moves here over packer balloons 20 and a movable connec tion part 21 caterpillar-shaped through a channel 13 . The tool guide system according to the invention is located under a protective sheath 22 made of plastic. A high-pressure water jet cutting nozzle 7 is used as the tool.

The user determines the on a screen Cutting position (TCP) on the channel wall. On Transformation calculator forms the two-dimensional Screen position on the three-dimensional spatial posi tion, cut it with the two-dimensional one curved channel surface and determines the drive positions of the two drives to use the water jet to reach the desired cutting position.

The device according to the invention, as in the Embodiments shown is one of the parallel structures and provides a closed kinematic chain. The kinematic system has two degrees of freedom. Drives and tools form one (real or virtual) tripod. The tool leg is rigid. The two drive legs are in length changeable and lead to the two degrees of freedom of the system. The tool works on a half line towards the tool leg. The intersection of the  The straight line with the working surface forms the TCP or tool engagement point. The area of movement of the Tool tip lies on a ball centered around the tool suspension on the bottom. The suspension points all three legs form a plane. The TCP is on one side of this level and is further from this Plane away as the radius of the sphere of motion space of the tool. The orientation of the beam regarding the respective point of impact is fixed and cannot be influenced.

The device according to the invention is not based on the Limited use of the tools already mentioned. So can all tool systems, one on one Generate a semi-straight "working beam", which on Energy exit point of the tool begins and ends straight or almost straight over a working distance linig continues to be used. examples for Such tool systems are high pressure water jets nozzles, abrasive water jet nozzles, high pressure cleaners, Permanent and pulse lasers, or launchers for explosive bullets.

Areas of application of the device according to the invention are all applications in which to process areas within the area with the tool jet achievable volume. The device can therefore, for example, as a pipe cleaning device, too known under the name "newt", or as laser cutting or water cutter for tight work spaces, e.g. B. for the guidance of cutters in the friction be set.  

It goes without saying that the invention not on the individual configurations of the Elements shown embodiments limited is. For example, the wearer can also use a Frame or the like can be realized. Can also make a difference Liche translatory drives are used. Examples of translatory drives can be refer to the specialist literature at any time.

In detail, the device according to the invention the following advantages over the systems of State of the art.

Power transmission from the beam to the guide linkage is low, so that only small drive track are necessary for the drive axles and low demands on the rigidity of the drive axes. The cable feeds must have no particular mobility because the Infeed of the lines near the fixed point selected can be. This ensures high mobility of the Tool with high rigidity of the feed enables a simple cable routing for pulsating supply line can be realized. The whole system is easy to seal and shows a lot small space compared to other systems.

Claims (8)

1. Device for guiding a blasting tool, which has an outlet opening ( 8 ) for a beam which exits along a first axis ( 3 ) of the tool, wherein

• the device has a carrier element ( 1 ) and a first and second translatory drive axis ( 2 a, 2 b) which are connected to the carrier element ( 1 ) and can be controlled independently of one another,
• - The tool or a holder for the tool at a first point ( 5 ) in the region of the first axis ( 3 ) with the support element ( 1 ) is connected so that the outlet opening ( 8 ) of the tool on a portion of a spherical surface around the first Point ( 5 ) can be moved as the center of the sphere, and
• - The first and second translational drive axis ( 2 a, 2 b) are each connected at a constant distance from the first point ( 5 ) directly or via intermediate elements ( 11 a, 11 b) with the tool or the holder, so that they are at the appropriate Drive movement can move the outlet opening ( 8 ) of the tool to any position within the portion of the spherical surface.

2. Device according to claim 1, characterized in that the first and second drive axles ( 2 a, 2 b) or the intermediate elements ( 11 a, 11 b) are connected to the tool or the holder at a common second point ( 4 ). 3. Apparatus according to claim 1 or 2, characterized in that the first and second drive axes ( 2 a, 2 b) form a real tripod with the first axis ( 3 ) of the tool. 4. Device according to one of claims 1 to 3, characterized in that the first and second drive axes ( 2 a, 2 b) are each connected via a rigid intermediate element ( 11 a, 11 b) of constant length to the tool or the holder, wherein the intermediate elements ( 11 a, 11 b) via joints ( 10 a, 10 b) with the drive axes ( 2 a, 2 b) are connected. 5. The device according to claim 4, characterized in that at least one of the drive axes ( 2 a, 2 b) is fixed in the orientation relative to the carrier element ( 1 ). 6. Device according to one of claims 1 to 5, characterized in that the first point ( 5 ) lies on the first axis ( 3 ). 7. Device according to one of claims 1 to 6, characterized in that the tool or the holder at the first point ( 5 ) via an axle joint with the carrier element ( 1 ) is connected. 8. Device according to one of claims 1 to 7, characterized in that the carrier element ( 1 ) has a drive for movement within a tube ( 13 ).