Patent Publication Number: US-2022229080-A1

Title: Positioning system for positioning end effectors

Description:
The invention relates to a positioning system for positioning end effectors, with a system main body, on which several working units are arranged next to one another in the axis direction of the y-axis of an x-y-z coordinate system, said working units whilst carrying out a working movement being linearly movable in the axis direction of a z-axis which is orthogonal to the y-axis for the positioning of an end effector which is respectively arranged on them. 
     DE 10 2014 013 552 B3 describes a such a positioning system which is designed as a metering system and concerning whose end effectors it is the case of metering units with which fluid quantities can be received from carrier substrates or can be delivered into carrier substrates. In particular, the fluid quantities are fluid samples, for example biochemical analysis samples which are to be analysed or treated in any other manner, or nutrient solutions or reagents of different types. The end effectors are assembled on working units of the positioning system, wherein the working units are linearly movable in the axis direction of a z-axis which as a rule is orientated vertically, in order to position the metering units in the necessary relative positions with respect to an assigned carrier substrate. Concerning the known positioning system, the working units always execute their working movements in a synchronous manner, since they are fixedly attached to a system main body, wherein the system main body is movable, in order to create the working movement of the working units including the end effectors which are attached thereto. 
     The exclusively unitary positionability of the working units and of the end effectors which are attached thereto, although permitting an inexpensive construction with regard to drive technology, however has the effect of a certain limitation in practical application. 
     WO 2006/000 115 A1 discloses a device for arranging pipetting or dispensing syringes in a system for handling liquid samples. The device has a robot arm, on which several blocks are movably arranged, these each being equipped with several pipetting or dispensing syringes. The pipetting or dispensing syringes are each individually vertically movable relative to the block which carries them. 
     A pipetting device which is equipped with pipetting units which are movable independently of one another is known from U.S. Pat. No. 9,101,922 B2. 
     DE 10 2012 015 083 B3 describes a dispensing head for dispensing fluid samples, which is equipped with several individual displaceable dispensers. 
     It is the object of the invention to create a positioning system which given a compact construction provides a high variability with regard to the positionability of the end effectors. 
     For achieving this object, in combination with the initially mentioned features, one envisages the working units being able to execute their working movements independently of one another and relative to the system main body, wherein an individual drive unit is assigned to each working unit for generating its working movement, wherein the drive units are arranged next to one another in the axis direction of the y-axis, furthermore the drive units each comprising a stator which is stationary with respect to the system main body, and a driven body which is actively moveable with respect to the stator whilst carrying out a driven movement, wherein the driven body is drivingly coupled to the assigned working unit via a coupling section for creating the working movement, and the stators being arranged in a distributed manner in several stator rows which are successive in the axis direction of the x-axis and are aligned in the axis direction of the y-axis, wherein the stators of the stator rows which are respectively adjacent in the axis direction of the x-axis are arranged offset to one another in the axis direction of the y-axis with a mutual overlapping. 
     A positioning system which is designed in this manner permits a positioning of present end effectors in the axis direction of the z-axis independently of one another, since the working units which on operation of the positioning system are equipped with the end effectors can be displaced relative to the system main body independently of one another for executing their working movements and are each coupled to an individual drive unit for generating their working movements. The working units can therefore be moved in a selective manner for example individually, sequentially or in groups or all together and be positioned as desired. This entails a very broad spectrum of application. Each drive unit has a stator which is fixed in a stationary manner with respect to the system main body, and a driven body which is drivable with respect to this into a driven movement, wherein the driven body is connected to the assigned working unit via a coupling section, so that a working movement of the assigned working unit can be taken from the driven movement of the driven body. Preferably, the drive units are of an electrically actuatable type, which permits very precise positionings with a low effort, but the drive concept can also for example be a fluidic and in particular a pneumatic drive concept. A very significant aspect lies in a surfaced distribution of the stators of the individual drive units, so that the stators of the present drive units do not all lie in one row, but are divided on to several linear rows which are denoted as stator rows and which extend in the axis direction of the y-axis and are arranged successively in the axis direction of the x-axis. The stators are each placed within these stator rows such that the stators of stator rows which are each adjacent in the axis direction of the x-axis are offset to one another in the axis direction of the y-axis, wherein the offset is selected such that the stators overlap in the axis direction of the y-axis. If one considers two arbitrary stators which are arranged next to one another in one and the same stator row, then one stator of the stator row which is adjacent in the axis direction of the y-axis is placed offset in the axis direction of the y-axis in a manner such that it overlaps with at least one and in particular with both aforementioned stators of the first mentioned stator row. Considering the fact that the stators usually have a greater width than the assigned coupling sections and working units, this provides the advantage that the working units can be placed tightly next to one another without being restricted by the stators. This produces particularly advantageous effects in the case of a positioning system which is conceived as a metering system and is used in order to fill or to empty carrier substrates which have receiver deepenings which are arranged very closely next to one another, as is regularly the case with so-called micro-titration plates. Nevertheless, the positioning system can also be used in a different manner, for example for handling objects if the end effectors are gripping units, for example vacuum gripping units. 
     Advantageous further developments of the invention are to be derived from the dependent claims. 
     As already mentioned, the positioning system can play out its advantages in a particularly convincing manner given a design as a metering system concerning which the end effectors are formed by metering units. Due to the movement and positioning of the working units which are provided with the metering units, said movement and positioning being independent of one another, fluid quantities in a metered manner can be received from a carrier substrate and/or be delivered into a carrier substrate, depending on the type of metering units, and specifically with a very high variability. If for example a micro-titration plate is placed below the metering units, then given a selective actuation of the working units, a selective metering with respect to receiver deepenings which are formed in a carrier substrate is possible. 
     The drive units are expediently grouped together in a compact space in a region of the stator main body which is denoted as a drive zone. The drive zone can be arranged for example adjacently to the working units in the axis direction of the z-axis, wherein they are located above the working units given a vertical z-axis. However, a spatial arrangement concerning which the drive zone is placed adjacently to the working units in the axis direction of the x-axis it is seen as being particularly favourable, wherein it is expedient of the x-axis is aligned horizontally. If one denotes that region in which the working units are situated as a working zone, then the drive zone and the working zone expediently lie next to one another in the axis direction of the x-axis, wherein an overlapping is indeed possible. 
     The coupling sections which ensure the drive-coupling of the drive bodies to the working units expediently extend in a region which is distanced with respect to the assigned stator in the axis direction of the z-axis. Herein, the coupling sections in the axis direction of the y-axis have a smaller width than the respectively assigned stator, which likewise applies to the working units which are coupled to the coupling sections. This design is particularly advantageous in combination with an arrangement of the drive zone and of the working zone which is adjacent to one another in the axis direction of the x-axis. In this case, the coupling sections of those drive units whose stators belong to a rear stator row, in front of which rear stator row the at least one stator row is arranged at the side which faces the working units, can extend past the stators of the at least one stator row which is arranged in front, at a distance with is measured in the axis direction of the x-axis, in order to be coupled to the assigned working unit. 
     Stators which belong to the same stator row can indeed bear on one another in the axis direction of the y-axis, but are preferably arranged distanced to one another. Expediently, the greater the number of existing stator rows, the larger is the distance between the stators which lie in the same stator row, said distance being present in the axis direction of the y-axis, wherein the distance however is preferably smaller than the width of each stator which is measured in the axis direction of the y-axis. 
     A particularly good ratio between the existing number of working units and compactness of the positioning system results if the stators are arranged in three and expediently in exactly three stator rows which are successive in the axis direction of the x-axis. 
     Stator rows which are adjacent in the axis direction of the x-axis can comprise a number of stators which is identical amongst one another, but however can also have a number of stators which is different from one another. By way of example, each stator row comprises three stators or four stators. Likewise for example, of consecutive stator rows, the respective one stator row has three stators and the respective other row only two stators. 
     Expediently, the stators together with all drive units are designed identically amongst one another. 
     It is further advantageous if all stators are placed at the same height in the axis direction of the z-axis in a common stator plane which is orthogonal to the z-axis. 
     A particularly favourable distribution of the stators has been found to result if the stators are placed such that when considered in the axis direction of the z-axis, several stator groups result, said stator groups each being composed of several stators which belong to stator rows which are successive in the axis direction of the x-axis and whose centre regions lie at least essentially on a connection straight line which is inclined with respect to the x-axis, wherein the connection straight lines of the several stator groups run parallel to one another. Preferably, the connection straight lines are inclined at an angle of 45 degrees with respect to the x-axis. 
     A particularly expedient design of the stators envisages an at least essentially square outline considered in the axis direction of the z-axis, wherein the outlines of all stators amongst one another are preferably identical amongst one another. Basically however, other stator outlines, for example round outlines are also possible. 
     The individual coupling sections in principle can be designed integrally with the respectively assigned driven body. This for example is when the driven body is a driven rod which is designed in the manner of a piston rod whose driven movement is a linear movement and whose end section functions as a coupling section. Basically however, it is seen as being more advantageous if each coupling section is designed separately with respect to the assigned driven body and with regard to drive is connected to the coupling section via suitable measures. A coupling section which is designed separately with respect to the driven body, with regard to drive can be connected to the driven body in a manner such that it either participates in the driven movement of the driven body or is driven by the driven movement of the driven body into a relative movement with respect to this. 
     It has been found to be particularly expedient if each coupling section is designed as a coupling slide which is displaceable with respect to the system main body. Each coupling slide is displaceably mounted on the system main body in the axis direction of the z-axis, wherein it is preferably the case of a displacement mounting which is independent of the driven bodies. The coupling slide is preferably designed in a plate-like manner and is aligned such that its plate plane runs orthogonally to the y-axis. This permits a very narrow construction width of the positioning system in the axis direction of the y-axis. 
     Each working unit expediently comprises a guide rod which is aligned parallel to the z-axis, is movable in the axis direction of the z-axis, is fastened to the coupling section of the assigned drive unit and is mounted on the system main body in a lineally displaceable manner. An assembly interface which serves for the attachment of an end effector and to which an application-specific end effector is fastened on operation of the positioning system is formed on the guide rod. The fastening can be effected in a direct manner or by way of a holder which is adapted the end effector and which can function as an adapter. 
     The guide rods of all working units are preferably arranged in a manner such that their longitudinal axes lie in a common plane which is denoted as a guide rod plane and runs orthogonally to the x-axis. 
     A preferred construction of the system main body envisages two carrier plates which each extend in a plane which is orthogonal to the z-axis and are arranged distanced to one another in the axis direction of the z-axis, so that they delimit an intermediate space which is to be denoted as a coupling space, since the coupling sections of the working units are located therein. 
     The two carrier plates are preferably held at a distance by way of a support structure which is integrated between them, wherein this support structure in particular is formed by side walls of the system main body which delimit the coupling space at the sides which are orientated at right angles to the z-axis. Each guide rod is placed such that it passes through both carrier plates and bridges the distance which is present between the carrier plates, wherein it is mounted in each carrier plate in a linearly displaceable manner in its longitudinal direction. Preferably, the stators of all drive units are fastened to one and the same of these two carrier plates. 
     It is advantageous if each drive unit comprises an individual drive module which comprises one of the stators and one of the driven bodies. On assembly of the positioning system, the drive modules can be handled independently of one another. The stator preferably represents a module housing of the drive module which defines the outer appearance of the drive module and via which the stator is fastened to the system main body. 
     The drive units are expediently electrical drive units, wherein the drive modules are designed as electrical drive modules. The electrical drive modules convert the fed electrical energy into a driven movement of the driven body. Preferably, the electrical drive modules are electric motors, in particular stepper motors, so that a very precise control which is closed-loop controlled in position is possible. Basically, the drive modules can however also be designed as fluid-actuated drive modules, for example as pneumatic drive modules and herein in particular as linear drives, for example pneumatic cylinders. 
     The driven body of each drive unit is expediently designed in a rod-like manner and is aligned such that its longitudinal axis runs in the axis direction of the z-axis. In this case, the rod-shaped driven bodies are aligned parallel to the possibly present guide rods of the drive units. Preferably, the rod-like driven body and the guide rod which belong to one and the same drive unit lie in a plane which is at right angles to the y-axis. 
     A particularly exact positioning of the working units is possible if the rod-like driven body of each drive unit can be driven into a rotational driven movement about its longitudinal axis. The driven body is in threaded engagement with the assigned coupling section, so that the rotational driven movement of the driven body results in a linear movement of the coupling section which is orientated in the axis direction of the z-axis and which creates an equally directed linear working movement of the working unit which is attached to the coupling section. The rod-like driven body in the region which interacts with the coupling section is expediently designed as a threaded spindle which has an outer thread. The coupling section expediently has a spindle nut with an inner thread, into which the threaded spindle of the driven body is screwed. 
     Expediently, each coupling section has several receiver structures which are distanced to one another in the axis direction of the x-axis, for the selective receiving of a spindle nut. This permits the use of identically designed coupling sections for the various drive units, independently of the stator row, in which the assigned stator is placed. 
    
    
     
       The invention is hereinafter explained in more detail by way of the accompanying drawing. In this are shown in: 
         FIG. 1  a preferred embodiment of the positioning system according to the invention in a design as a metering system which is suitable for receiving and/or delivering fluid quantities, in a perspective view, wherein a carrier substrate which is to be processed by the positioning system is also shown, 
         FIG. 2  the positioning system of  FIG. 1  from a different viewing direction, again in a perspective representation, 
         FIG. 3  a front view of the positioning system with a viewing direction according to arrow III of  FIG. 1 , 
         FIG. 4  a longitudinal section of the positioning system according to the section line IV-IV of  FIGS. 1, 3 and 6 , 
         FIG. 5  a cross section of the positioning system according to the section line V-V of  FIG. 4 , 
         FIG. 6  a further cross section of the positioning system according to the section line VI-VI of  FIG. 4 , 
         FIG. 7  a further longitudinal section of the positioning system according to section line VII-VII of  FIG. 4 , 
         FIG. 8  an individual representation of one of the several positioning units which are contained in the positioning system and which are each composed of a drive unit and of a working unit, and specifically in the state of the working unit in which it is equipped with an end effector and according to the detail VIII which is framed in  FIG. 5  in a dot-dashed manner, and 
         FIG. 9  in a perspective representation, a detail of a further embodiment of the positioning system which differing from the embodiment example of  FIGS. 1 to 8  comprises an equal number of stators within the individual stator rows, wherein only the drive units and the working units which are attached thereto are shown for the purpose of a better overview. 
     
    
    
     The positioning system which as a whole is given the reference numeral  1  has a system main unit  2  which can be placed at the location of application and which expediently comprises at least one fastening interface  3 , via which it can be fixed to a carrier structure which is not illustrated further. This carrier structure can be designed in a stationary manner and for example as a support frame. The support structure can also be a handling unit, with whose help the system main unit  2  can be moved in space. 
     The system main unit  2  has a system main body  4  and a plurality of positioning units  5  which are arranged on the system main body  4 . Such a positioning unit  5  is represented individually in  FIG. 8 . Each positioning unit  5  comprises a working unit  6  and a drive unit  7  which with regard to drive is coupled to the working unit  6 . By way of the drive unit  7 , the working unit  6  can be driven into a linear working movement  8  which is indicated by a double arrow. 
     An assembly interface  9  for an end effector  10  is located on the drive unit  7 . On operation of the positioning system, an end effector  10  which is matched to the positioning task is attached to the assembly interface  9 , so that it participates in the working movement  8 . The end effector  10  can be an integral constituent of the working unit  6 . 
     In the course of the working movement  8 , each working unit  6  and the end effector  10  which is assigned to it can not only be moved linearly but can also be positioned if required, which is to say can be fixedly held for a while at a desired location of the displacement path. 
     The positioning system  1  can be designed and used for a variety of purposes. For example, it is suitable for handling measures, in which case the end effectors  10  are designed as grippers and in particular as vacuum grippers, with which objects can be gripped and firmly held during relocation. 
     A preferred field of application of the positioning system  1  however is the metering of fluid quantities, in particular in the field of medical technology, in the pharmaceutical field and/or concerning arbitrary biological or biochemical measures. The fluid quantities which are to be metered here are mostly denoted as fluid samples. The illustrated positioning system  2  is designed for such an application case, so that it represents a metering system  1   a . The end effectors  10  of the individual positioning units  5  in this case are each designed as a metering unit  10   a  which is capable of receiving a certain fluid quantity or fluid sample and of also delivering it again. 
     Fluid quantities which are to be received are regularly made available in a matrix-type distribution with a suitably constructed carrier substrate  11 , wherein such a carrier substrate  11  in particular is a so-called micro-titration plate. The carrier substrate  11  has a multitude of receiving deepenings  12 , in which each of which a fluid quantity can be provided. The fluid quantities can be removed from the receiver deepenings  12  with the help of the metering units  10   a  and be subjected to a subsequent treatment, for example an analysis. The metering system  1   a  however can also be used to deliver treated or untreated fluid quantities into the receiver deepenings  12  of such a carrier substrate  11  for storage or for further treatment. In this case, the metering units  10   a  expediently each comprise a metering valve  13  which is the case with the illustrated embodiment example. The fluid to be metered is fed to the respective metering valve  13  via a fluid conduit  14  which is connected thereto and concerning which are a rigid pipe conduit and/or a flexible tube conduit. By way of example, the metering valves  13  are connected via fluid conduits  14  to a fluid store  15  which provides the fluid to be metered. 
     With reference to a Cartesian x-y-z coordinate system, the system main unit  2  has spatial extensions in the axis direction of an x-axis, of a y-axis which is at right angles to the x-axis and of a z-axis which is at right angles to the x-axis and well as the y-axis. Directions which run in the axis direction of one of these Cartesian axes are hereinafter also only denoted as x-axis direction, y-axis direction and z-axis direction for simplification. 
     Concerning a common operationally ready spatial alignment of the system main unit  2 , the z-axis direction runs vertically, whereas the x-axis direction and the y-axis direction each run horizontally. This particularly applies to a metering system  1   a.    
     Each metering unit  10   a  at one end has a metering opening  16  which for example is defined by a pipette or by a syringe needle and which by way of example points downwards in the z-axis direction. For receiving and/or delivering a fluid quantity, the carrier substrate  11  is positioned below the metering units  10   a  such that each metering opening  16  comes to lie above one of the receiver deepenings  12 . The metering units  10  are immersed with their metering openings  16  into the receiver deepenings  12  and also moved out again by way of the working movement  8  which is orientated in the z-direction. 
     The working units  6  which are provided by way of example with the metering units  10   a  are present in multiple for the purpose of a rational operating manner, so that if necessary a plurality of receiver deepenings  12  can be filled or emptied simultaneously. The several working units  7  are arranged next to one another in the y-axis direction. Accordingly, the metering openings  16  lie in an opening row which follows in the y-axis direction. 
     Since the receiver deepenings  12  in the case of the illustrated application example are relatively small and are arranged next to one another in a tight raster, the metering openings  16   a  of the metering units  10  must also lie tightly next to one another. This by way of example can be ensured without any problem by way of a correspondingly narrow design of the metering units  10   a  and all of the working units  6  in the y-axis direction. The multitude of working unit  6  can be arranged next to one another in the y-axis direction in the tightest of spaces. 
     An advantage of the positioning system  1  according to the invention lies in the fact that the system main unit  2  can also be realised with small dimensions in the y-axis direction in the region of the drive units  7 , so that the system main unit  2  as a whole has very compact dimensions in the y-axis direction. This encourages an application given restricted spatial conditions and a multiple arrangement of system main units  2  in a tight space. 
     The positioning units  5  which each comprise a drive unit  7  and a working unit  6  are arranged on the system main body  4  lying next to one another in the y-axis direction. The working unit  6  and the drive unit  7  are arranged successively in the x-direction within the respective positioning unit  5 . As a whole, by way of example an arrangement concerning which all working units  6  lie in a region which is denoted as a working zone  17  and all drive units  7  lie in a region which is denoted as a drive zone  18  results from this, wherein the working zone  17  and the drive zone  18  are arranged successively in the x-axis direction. The drive zone  18  expediently lies at essentially the same height as the working zone  17  in the z-axis direction. 
     The working units  6  can execute their working movements  8  relative to the system main body  4  and independently of one another. The system main body  4  as a result can consequently retains its spatial position in an unchanged manner given working movements of the working units  6 . For this reason, only small masses need to be moved, in order to displace the end effectors  10  in the z-axis direction and to position them. 
     Since an individual drive unit  7  is assigned to each working unit  6 , the end effectors  10  can be moved independently of one another. The positioning system  1  expediently comprises an electronic control device  19  which is electrically connected to the individual drive units  7  and which permits an individual electrical control of the drive units  7 . By way of example, the electronic control device  19  can initiate only individual working units  6  into being moved in a defined sequence, the working units being moved in groups or all working units  6  being moved. 
     Each drive unit preferably comprises a drive module  22  which comprises a stator  23  and a driven body  24  which can be driven with respect to this into a driven movement  25 . Particularly advantageous is the use of electrical drive modules  22  which by way of example is the case. Here, fed electrical energy is converted directly into movement energy of the driven body  24 . Basically however, fluid-actuated drive modules  22  can also be applied. 
     Preferably and according to the example, each drive module  22  is formed by an electric motor, concerning which it is particularly a stepper motor with a driven shaft  66  which belongs to the driven body  24  and which with regard to rotation angle can be positioned in a very precise manner. 
     The driven movement  25  of the driven body  24  which is produced by the drive module  22  is preferably a rotation movement which is the case with the illustrated embodiment examples. The driven body  24  is herein designed in a rod-like manner and has a longitudinal axis  24   a  which forms the rotation axis for the rotational driven movement  25 . The drive modules  22  in particular are installed such that the longitudinal axes  24   a  of the driven bodies  24  are aligned in the z-axis direction. Accordingly, the longitudinal axes  24   a  of the driven bodies  24  coincide with the movement direction of the working movement  8 . 
     The drive modules  22  are electrically connected to the electronic control device  19 , from which they receive electrical control signals, by way of which the driven movement  25  of its driven body  24  can be created for moving and positioning the working units  6 . 
     The drive modules  22  are each fastened to the system main body  4  via their stator  23 , so that they are stationary with respect to this. By way of example, each stator  23  defines a module housing  23   a  which is fixed to the system main body  4  by way of fastening screws which are not illustrated further. 
     The drive unit  7  of each positioning unit  5  comprises a coupling section  26  for drive-coupling of the driven body  24  to the working unit  6 . The coupling section  26  is fastened to the working unit  6  via a fastening device  27 , so that these two constituents always can only be moved together. The coupling section  26  can execute a to and fro linear movement  28  relative to the system main body  4  in the z-axis direction. This linear movement  28  can be created by way of the interaction with the driven body  24 . Its driven movement  25  creates the linear movement  28  of the coupling section  26 , which results in a simultaneous execution of the working movement  8  by the working unit  6 . 
     Expediently, a position sensor  20  by way of which the current position of the assigned working unit  6  can be detected in a direct or indirect manner is assigned to each positioning unit  5 . The position sensors  20  provide electrical position signals which are fed to the electronic control device  19 , to which according to  FIG. 4  all position sensors  20  are electrically connected. An actuation of the working units  6  which is closed-loop controlled in position is possible by way of this. 
     The positioning units  5  by way of example are carried by two first and second carrier plates  31 ,  32  of the system main body  4  which are arranged distanced to one another in the axis direction of the z-axis. Each carrier plate  31 ,  32  has a rigid structure and extends in a plane which is orthogonal to the z-axis. In the advantageous vertical alignment of the z-axis which is realised by way of example, the first carrier plate  31  lies at a distance above the second carrier plate  32 . Side walls  33  of the system main body  4  which are integrated between these two carrier plates  31 ,  32  and to which the carrier plates  31 ,  32  are fastened set the distance which is present between the two carrier plates  31 ,  32 . 
     The two carrier plates  31 ,  32  commonly delimit an intermediate space, in which all coupling sections  26  are arranged and which is therefore denoted as a coupling space  34 . 
     Together with the side walls  33 , the two carrier plates  31 ,  32  form a housing structure expediently with a cubic outer contour. 
     A front side wall  33   a  which is assigned to the transition region between the working zone  17  and the drive zone  18 , and a rear side wall  33   b  which lies opposite the front side wall  33   a  in the x-axis direction are located below the side walls  33 . Two lateral side walls  33   c ,  33   d  which lies opposite one another in the y-axis direction extend therebetween. The front side wall  33   a  and the two lateral side walls  33   c    33   d  are expediently grouped together into a single-piece wall structure, onto which the rear side wall  33   b  is applied in the manner of a lid and in particular in a releasable manner. 
     The stators  23  of all drive units  7  are expediently fastened to one and the same carrier plate  31  or  32 , wherein in particular and by way of example this is the first carrier plate  31 . The stators  23  are seated on an equipping surface  35  of the first carrier plate  31  which is away from the coupling space  34 , so that by way of example they project upwards from the first carrier plate  31 . In particular, the fastening is effected via the module housing  23   a.    
     The rod-like driven bodies  24  project through openings of the first carrier plates  31  into the coupling space  34 , by way of example from above. 
     Each working unit  6  expediently has a guide rod  36  which is aligned in the z-axis direction and is movable in the z-axis direction relative to the system main body  4  for carrying out the working movement  8 . The longitudinal axis  36   a  of each guide rod  36  runs in the z-axis direction and is consequently parallel to the longitudinal axis  24   a  of the driven body  24  which belongs to the same positioning unit  5 . 
     Each guide rod  36  is mounted on the system main body  4  in a linearly displaceable manner in its longitudinal direction and accordingly in the z-axis direction. By way of example, a displacement mounting is effected at two locations, specifically on each of the two carrier plates  31 ,  32 . Each guide rod  36  is placed such that it passes through both carrier plates  31 ,  32 , wherein it passes through the coupling space  34  in the z-axis direction and with two first and second rod end sections  36   b ,  36   c  which are opposite one another projects beyond the respectively assigned carrier plate  31 ,  32  at the outer side which is opposite to the coupling space  24 . The openings of the carrier plates  31 ,  32 , through which the guide rod  36  passes are designed as guide openings  37  which have a guide surface which guides in a slidingly displaceable manner and which radially supports the guide rod  36 . The guide surface can be formed by a guide bush which is inserted into the guide opening  37 . 
     The guide rods  36  at the outside in particular are contoured in a circularly cylindrical manner, which accordingly also applies to the inner periphery of the guide openings  37 . By way of example, the guide rods  36  are designed in a tubular manner, by which means the manufacturing costs and the moved masses are reduced. 
     Expediently, the aforementioned assembly interface  9  for the attachment of the end effector  10  is located on the second end section  36   c  of each guide rod  36  which by way of example points downwards. By way of example, a holder  38  which in particular functions as an adapter and via which the end effector  10  is fastened to the assembly interface  9  is assigned to the end effector  10 . The fastening is effected by way of a fastening screw  41  which passes through the holder  38 , is screwed into the guide rod  36  at the face side and which is only indicated symbolically. 
     Expediently, a holding element  43  which projects transversely in a direction pointing away from the drive zone  18  and which is used for the fixation of the fluid conduit  14  which departs upwards from the assigned metering unit  10  is fastened to the first end section  36   b  of the guide rod  36 —here by way of a fastening screw  42  which is only indicated symbolically. 
     The guide rods  36  are preferably arranged such that the longitudinal axes  36   a  of the guide rods  36  of all working units  6  lie in a common plane which is denoted as a guide rod plane  44  and which runs orthogonally to the x-axis. The guide rod plane  44  in particular is placed such that it lies in the transition region between the working zone  17  and the drive zone  18 . Preferably, the assigned guide rod  36  passes through each coupling section  26 , wherein a fixed connection between the two components is created by the fastening device  27 . By way of example, the fastening device  27  comprises several fastening screws, by way of which the coupling section  26  is clamped to the guide rod  36 . 
     Preferably, all coupling sections  26  are designed in a movable manner in the manner of a slide, so that they each form a coupling slide  45  which can execute a linear movement  28  and for this purpose is guided on the system main body  4  in a linearly displaceable manner. In the course of the linear movement  28 , the coupling slide  45  can be displaced between a first end position which is approached to the first carrier plate  31  and a second end position which is approached to the second carrier plate  32 , wherein the coupled drive unit  6  participates in this linear movement  28 . 
     The coupling slides  45  undergo their linear guidance on the one hand by the guide rod  36  which is connected to them and which as mentioned is linearly displaceably mounted on the two carrier plates  31 ,  32 . The guide rod  36  is fixed on a front end section of the coupling slide  45  which faces the working zone  17 . 
     Each coupling slide  45  undergoes an additional further linear guidance by way of example at its rear end section  46  which is away from the working zone  17 . Here, the coupling sections  45  independently of one another and each with a guide projection  47  engage in a slidingly displaceable manner into a guide groove  48  of the system main body  4  which extends in the z-axis direction. The guide grooves  48  extend linearly in the z-axis direction and are arranged next to one another in the y-axis direction with a parallel alignment, wherein by way of example they are formed on the inner surface of the rear side wall  33   b.    
     The position sensors  20  preferably cooperate with the coupling sections  26 . Expediently, each position sensor  20  is designed in a manner in which it is sensitive to a magnetic field, wherein the assigned coupling section  26  comprises a permanent magnet for the contact-free actuation of the position sensor  20 . By way of example, the position sensors  20  are fixed in fastening grooves  21  which are formed in the system main body  4 , in particular in the rear side wall  33   a  at the outside. 
     Each coupling slide  45  is expediently designed in a plate-like manner and is aligned such that its plate plane  45   a  which is parallel to the two largest outer surfaces runs orthogonally to the y-axis. This provides the possibility which is realised by way of example, of placing the plate-like coupling slides  45  next to one another in a restricted space in a space-saving manner with plate planes  45   a  which are parallel to one another. This is well evident from the  FIGS. 5 and 6 . 
     Expediently, with regard to each drive unit  7 , the longitudinal axis  24   a  of the rod-like driven body and the longitudinal axis  36   a  of the guide rod  36  extend in the plate plane  45   a  of the plate-like coupling section  45 . 
     In particular, if with regard to the driven movement  25  of the driven body  24  it is the case of a linear movement in the z-axis direction, then the coupling section  26  and the driven body  24  can be fixedly connected to one another in an arbitrary manner and in particular also be designed in an integral manner. Both components then always herewith carry out a synchronous unitary linear movement for generating the working movement  8 . 
     By way of example, each driven body  24  however with regard to drive is connected to the assigned coupling section  26  in a manner such that the rotational driven movement  25  is converted into the linear movement  28 . 
     For this, at least the length section of the rod-like driven body  24  which extends in the coupling space  34  is designed in the manner of a threaded spindle, so that one can denote it is a threaded spindle section  49  of the driven body  24  which has an outer thread  52  on its outer periphery. The driven body  24  engages with the threaded spindle section  49  into an inner thread  52  of the coupling section  26 . Since the inner thread  52  is formed in a non-rotatable manner on the coupling section  26  which for its part is fixed in a non-rotational manner with respect to the system main body  4 , a rotational driven movement  25  of the threaded spindle section  49  creates the linear movement  28 , since the inner thread  52  together with the assigned coupling section  26  move in the longitudinal direction of the threaded spindle section  49 . 
     By way of example, the threaded engagement is realised by way of the coupling slide  45  comprising a preferably plate-like slide body  53 , into which a separate spindle nut  54  which comprises the inner thread  52  is stuck. The spindle nut  54  is seated in a receiver structure  55  of the slide body  53  which by way of example is formed by a circularly cylindrical opening which passes through the solid body  53  in the y-axis direction and into which the spindle nut  54  which is provided with a complementary circularly cylindrical outer periphery is inserted. The inner thread  52  is a constituent of a threaded bore which passes diametrically through the spindle nut  54 . A through-bore  56  which passes through the slide body  53  in the z-axis direction and which goes through the circularly cylindrical opening of the receiver structure  55  is aligned with the threaded bore of the spindle nut  54  and through which the assigned threaded spindle section  49  passes in a freely rotatably manner without a threaded engagement. 
     The slide body  53  can consist of a plastic material which is inexpensive, wherein the spindle nut  54  expediently consists of steel. 
     The spindle nut  54  in principle is rotatable in the receiver structure  55  with its circularly cylindrical outer periphery and is also displaceable in the y-axis direction, so that it can automatically align itself with respect to the threaded spindle section  49  which engages into it, which simplifies the assembly and reduces the wear. 
     Concerning an embodiment example which is not illustrated, the coupling slide  45  has a slide body  53 , in which the inner thread  52  is integrally formed. Here, a threaded bore which forms the inner thread  52  passes through the slide body  53 . 
     The stators  23  of all drive units  7  are expediently arranged in a protected manner below a cover hood  57  which is arranged in the region of the equipping surface  35 . The cover hood  57  is not shown in all figures. 
     The stators  23  are arranged on the equipping surface  35  with a particularly advantageous distribution. Such can be understood particularly well by way of  FIGS. 5 and 9 , wherein  FIG. 5  represents a plan view upon the stators  23  with a view in the z-direction 
     The present stators  23  are arranged in several linear rows which are each denoted as a stator row  58 , and extend in the y-axis direction and are arranged successively in the x-axis direction. The stator rows  58  are rendered recognisable in the drawing by dot-dashed straight lines which simultaneously define the respective row alignment. 
     All stators  23  are divided onto the existing several stator rows  58 . According to  FIG. 9 , the individual stator rows  58  amongst one another can have the same number of stators  23 . However, it is likewise possible to provide the stator rows  58  with a different number of stators  23 , concerning which  FIG. 5  provides an example. 
     Concerning both illustrated embodiment examples, the stators  23  are divided onto three stator rows  58 . However, without further ado a larger or smaller number of stator rows  58  per system main unit  2  is also possible. 
     The embodiment of  FIG. 9  shows a system main unit  2  which comprises twelve positioning units  5  and accordingly also twelve stators  23 . These here are arranged in three stator rows  58  each with four stators  23 . Concerning the embodiment example of  FIGS. 1 to 8 , the system main unit  2  as a whole comprises eight positioning units  5  and accordingly also eight stators  23 , wherein these eight stators  23  are divided onto two stator rows  58  with three stators and a third stator row  58  with two stators  23 . The stator row  58  with only two stators is expediently located between the two stator rows  58  which are each with three stators  23 . 
     The outlined arrangement of the stators  23  which is distributed in rows results due to a correspondingly distributed arrangement of the respective drive modules  22 , said drive modules each comprising one of the stators. 
     All stators  23  are preferably placed at the same height with respect to an axis direction of the z-axis, in a common plane which is denoted as a stator plane  61  and which extends at right angles to the z-axis. 
     A particularity of the stator distribution lies in the fact that the stators  23  are not arranged on a line in an flush manner in the x-direction, but that the stators  23  of the respectively adjacent stator rows  58  are arranged offset to one another in the y-axis direction, and specifically in a manner such that they mutually overlap in the y-axis direction. 
     When considered in the z-axis direction, all stators  23  expediently have the same outline. Preferably, it is an at least essentially square outlines, which is the case with the illustrated embodiment examples. Herein, the stators  23  are orientated such that two of its four outer surfaces which are opposite one another are each aligned parallel to the stator rows  58 . 
     Preferably, and according to the illustrated embodiment example, stators  23  which belong to the same stator row  58  are arranged distanced to one another in the axis direction of the y-axis. By way of this, an intermediate space  62  results between two consecutively arranged stators  23  of each stator row  58 . The intermediate space  62  is preferably narrower than the width of the stators  23  which is measured in the same direction. 
     In particular, in dependence on the base surface of the stators  23  at right angles to the z-axis, an arrangement concerning which the stators  23  bear on one another within at least one and preferably within each stator row  58  is also possible. 
     The stators  23  which belong to the stator rows  58  which are successive in the x-axis direction are expediently arranged at a certain distance to one another in the x-direction, wherein this distance in particular is lower than the distance between the stators  23  which belong to the respectively same stator row  58 . 
     Each stator  23  has a centre region  63  when considered in the z-axis direction. This centre region  63  expediently lies on the longitudinal axis of the driven body  24  which is assigned to the respective stator  23 . A particularly advantageous distribution of the stators  23  in the stator plane  61  envisages the resulting of several stator groups  64  which are each composed of several stators  23  which belong to stator rows  58  which are consecutive in the direction of the x-axis, and whose centre regions  63  lie at least essentially on an imaginary connection straight line  65  which is inclined with respect to the x-axis. The connection straight lines  65  of the several stator groups  64  lie parallel to one another. The inclination of the connection straight lines  65  of 45 degrees with respect to the x-axis and which is realised with the embodiment examples is particularly advantageous. 
     Concerning the embodiment example of  FIGS. 1 to 8 , two stator groups  64  which are each composed of three stators  23  and which have the aforementioned particularities are present. Concerning the embodiment example of  FIG. 9 , four such stator groups  64  result, of which three in total have three stators and a fourth stator group  64  consists of two stators  23 . 
     Disregarding those stators  23  which lie on a common connection straight line  65  whilst forming a stator group  64 , at least one further stator  23  can yet also be present, such not belonging to such type of stator group  64 . 
     Expediently, each stator row  58  comprises at least one stator  23  which in the y-axis direction overlaps with two stators  23  of at least one stator row  58  which is adjacent in the x-direction. It is to be understood that one or more stator rows  58  can comprise at least one stator  23  which lies at the end of the stator row  58  and which with only one stator  23  overlaps at least one adjacent stator row  58 . 
     On account of the above-explained arrangement or distribution of stators  23  and of drive modules  22  which contain the stators  23 , the system main unit  2  can be realised in the drive zone  18  with small dimensions in the y-axis direction, although individual stators  23  have a greater width than each of the working units  6 . 
     The working units  6  are narrower than the individual stators  23  in the y-axis direction. Added to this is the fact that expediently each length section of each driven body  24  which extends outside the stator  23  as well as each coupling section  26  have a smaller width in the y-axis direction than the associated stator  23 . 
     In this manner, in a projection onto a plane which is at right angles to the z-axis according to  FIG. 5 , there remains sufficient space between the coupling sections  26  of those drive units  7  whose stators lie in the same stator row  58 , for those coupling sections  26  which belong to those drive units  6  whose stators  23  are arranged in each subsequently stator row  58  to engage past. 
     If one considers the frontmost stator row  58  which lies closest to the working zones  17 , then the coupling sections  26  which belong to their stators  23  amongst one another have a distance in the y-axis direction which is dimensioned adequately large, so that the coupling sections which are assigned to the stators  23  of the subsequent stator row  58  extend therebetween. The mutual distances by way of example are so large than the coupling sections  26  which are assigned to each further stator row  58  can also engage through. 
     Since the coupling sections  26  are arranged at a distance in front of the stators  23  in the z-axis direction, by way of example therefore to the bottom, they can extend pass the individual stators  23  in the x-axis direction without further ado. 
     Preferably, within the individual stator rows  58 , the distance measured in the y-axis direction between the centre regions  63  of stators  23  which are directly adjacent in each case is at least a multiple of the width of the coupling sections  26  which is measured in the y-axis direction, wherein concerning the aforementioned multiple, this is the number of stator rows which are present in total. If therefore as with the embodiment example in total three stator rows  58  are present, the distance between the centre regions  63  of the respectively adjacent stators  23  within each stator row  58  is at least triple the width of the coupling sections  26 . For the benefit of a compact construction width of the system base unit  2 , one would expediently select the distance such that the coupling sections  26  which extend therebetween either bear on one another in a slidingly displaceable manner or are arranged only at a small distance to one another. 
     In principle, the shorter the coupling sections  26 , the closer do the assigned drive modules  22  or their stators  23  lie to the working zone  17 , since then the distance between the driven body  24  and the assigned guide rod  36  is correspondingly smaller. 
     Nevertheless, it is seen as being advantageous if according to the embodiment examples, all coupling sections  26  have the same length in the x-axis direction, which provides the advantage of all coupling sections  26  being able to be guided in a linearly displaceable manner on the rear side wall  33   b.    
     Furthermore this provides the advantageous possibility of designing the coupling sections  26  as coupling slides  45  with slide bodies  53  which are identical amongst one another. This applies to the illustrated embodiment examples. 
     In order, irrespective of the design identity of the slide bodies  53 , for a drive coupling to the driven bodies  24  which are placed differently distanced to the working zone  17 , expediently each slide body  53  is provided with a number of receiver structures  55  which corresponds to the number of stator rows  58 , the distance of said receiver structures to one another measured in the x-axis direction corresponding to the mutual distance between the stator rows  58 . Of these several receiver structures  55  it is then only that one which is equipped with a spindle nut  54  which is assigned to one of the driven bodies  24 . 
     Alternatively, each coupling section  26  could also be provided with a number of inner threads  52  which corresponds to the number of present stator rows  28 , of which inner threads at the same time in each case only one is used for a threaded engagement with a threaded spindle section  49 . 
     If the drive modules  22  are designed as rotation drives, which is the case given the use of electric motors, then a further already mentioned driven shaft  66  extends in the inside of the stator  23 , said driven shaft representing a length section of the driven body  24  and being coupled to the threaded spindle section  49  in a rotationally fixed manner. The driven shaft  66  and the threaded spindle section  49  can be designed as one piece or also as separate components which are fixedly connected to one another.