Patent Publication Number: US-2023144252-A1

Title: Waste sorting robot

Description:
The present invention relates to a waste sorting robot for sorting waste objects. 
     In the waste management industry, industrial and domestic waste is increasingly being sorted in order to recover and recycle useful components. Each type of waste, or “fraction” of waste can have a different use and value. If waste is not sorted, then it often ends up in landfill or incineration which has an undesirable environmental and economic impact. 
     Industrial waste may be passed to waste management centres because handling and disposing of waste is time consuming and requires specialist equipment. Accordingly, a waste management centre may sort waste to collect the most valuable and useful fractions. For example, industrial waste may include mixed wood and metal fractions (as well as other fractions) and sorted wood and metal fractions can be reused and sold to recyclers. Waste which is sorted into a substantially homogeneous fraction is more desirable and economical for recyclers. This is because less processing of the material is required before being recycled into new products and materials. 
     It is known to sort domestic and industrial waste in different ways. For many years waste has been manually sorted by hand on a conveyor belt. However hand sorting waste can be arduous and dangerous to the human sorter depending on the type of industrial or domestic waste being sorted. Furthermore, some waste sorting plants which use human sorters require multiple shifts in order to increase the output of sorted waste. 
     One approach for improving the safety and the output of waste sorting is to automate one or more aspects of the waste sorting. The automation can comprise a controller sending control and movement instructions to a manipulator for interacting with the physical objects. The combination of a controller sending control instructions to a manipulator can also be referred to as a “robot”. 
     The working volume/area can also include chutes which are not part of the surface of a conveyor belt. 
     One known robot for automatic sorting of waste is a “gantry” robot. A gantry robot comprises a frame or gantry which engages the floor and bridges over a working area such as a conveyor belt. The gantry supports the weight of the manipulator and an object that the manipulator grips. The gantry robot comprises one or more axes of control which move in a straight line (e.g. linear). Normally the axes of control of a gantry robot are arranged at right angles to each other. 
     A gantry robot may pick objects from the conveyor belt and drop the picked objects into a chute. A chute comprises an opening which is in communication with a bin or another conveyor belt for receiving a particular fraction of waste. The picked objects placed in the bin or on the conveyor belt can then be moved to another location or step in waste processing. This means a picked object of a certain waste fraction is dropped into the corresponding chute. Known gantry robots may have a four or more chutes located at the four corners of the rectangular working space for receiving the different fractions. 
     One known waste sorting gantry robot is shown in international patent application PCT/FI2019/050318 which shows a waste sorting gantry robot with a manipulator moveable on the gantry frame in three orthogonal directions actuated with a servo for each orthogonal direction. The manipulator comprises a pair of jaws for gripping and sorting waste objects. Since the manipulator travels on the gantry frame, one or more servos must be moved as well as the manipulator in order that the manipulator can travel in three degrees of freedom. This increases the weight and the inertia of the manipulator when travelling in one of the orthogonal directions e.g. the x direction. This means that the frame must be sufficiently large to allow the manipulator to travel and accelerate to the correct speed when picking and sorting waste objects. 
     Examples of the present invention aim to address the aforementioned problems. 
     According to an aspect of the present invention, there is a waste sorting robot comprising: a frame; a manipulator moveably mounted to the frame and comprising a gripper for interacting with one or more waste objects to be sorted within a working area; and a conveyor for moving the one or more waste objects towards the working area; wherein at least a portion of the manipulator is rotatable with respect to the frame such that the gripper is moveable lengthways along the conveyor within the working area. 
     This means that the waste sorting gantry frame robot only needs to provide a single horizontal beam across the conveyor belt reducing the weight and complexity of the waste sorting robot. This is because the gantry frame of the waste sorting gantry frame robot  100  does not need to allow movement of the manipulator mounted on a horizontal beam with an X-axis servo. By reducing the complexity of the gantry frame, this means that installation of the waste sorting gantry frame robot on a picking line is simplified and can be achieved by a single person. 
     By using a suction gripper which pivots, the mass of the manipulator can be greatly reduced. Movement of the horizontal beam or the manipulator can be achieved with a limited angular movement. This means the inertia of the manipulator is reduced and the manipulator can be accelerated more quickly. This means that the manipulator can move faster and the speed of the conveyor belt  10  can be increased. Advantageously, by increasing the speed of the conveyor belt, the objects to be sorted on the conveyor belt are more singularized and less likely to be overlapping. This means that the manipulation and object recognition is easier. This increases the processing rate (e.g. tons/hour) because the number of objects per hour which is fed to the robot increases. 
     This means that the waste sorting robot is suitable for a working area with a limited available distance in the X-axis but scalable in the Y-axis. Furthermore, the particular arrangement is advantageous for a waste sorting robot. This is because a high precision of movement of the manipulator similar to conventional robotics is not required. This is because the waste objects deform or move on the conveyor belt and waste objects are successfully picked with the waste sorting robot discussed in reference to the Figures. 
     Optionally the portion of the manipulator is rotatable about an axis perpendicular to the longitudinal axis of the conveyor. 
     Optionally, the manipulator is moveably mounted on a cross beam over the conveyor. 
     Optionally the manipulator is slidable along the cross beam. 
     Optionally waste sorting robot comprises a servo for moving the manipulator along the cross beam. 
     Optionally the portion of the manipulator is pivotable with respect to the cross beam. 
     Optionally the portion of the manipulator is pivotally coupled to a carriage mounted to the cross beam. 
     Optionally a first pneumatic actuator is coupled to the portion of the manipulator and configured to rotate the portion of the manipulator with respect to the frame. 
     Optionally the first pneumatic actuator is coupled between the portion of the manipulator and the carriage. 
     Optionally a second pneumatic actuator is coupled to the gripper and configured to adjust the height of the gripper above the conveyor. 
     Optionally the gripper is a suction gripper. 
     Optionally the first pneumatic actuator, the second pneumatic actuator and/or the suction gripper are connected to a single pneumatic control system. 
     Optionally the manipulator and the cross beam rotate together. 
     Optionally the waste sorting robot comprises a plurality of manipulators rotatable with respect to the frame such that a grippers associated with each manipulator is moveable lengthways along the conveyor. 
     Optionally the plurality of manipulators are located along the length of the conveyor. 
     Optionally the plurality of manipulators are mounted on the same cross beam or the same frame. 
     Optionally the manipulator comprises an articulated arm with one or more pivoting joints. 
     Optionally each pivoting joint coupled to an associated actuator. 
     Optionally the manipulator comprises a plurality of linked articulated arms. 
     Optionally the waste sorting robot is a waste sorting gantry robot. 
     Optionally the frame comprises a cross-beam with a longitudinal axis and the longitudinal axis of the cross-beam is fixed with respect to the working area. 
     Optionally the manipulator comprises at least one pneumatic actuator coupled the manipulator and/or the gripper configured to adjust the height of the gripper with respect to the working area. 
     Optionally the manipulator/and or the gripper are slidable in a direction perpendicular to the working area to adjust the height of the gripper with respect to the working area. 
     Optionally the manipulator comprises at least one pneumatic actuator coupled the manipulator configured to slide the manipulator on the frame across the conveyor in the working area. 
     In a second aspect of the invention there is provided a method of controlling a waste sorting robot having a frame, a manipulator moveably mounted to the frame, and a gripper for interacting with one or more waste objects to be sorted within a working area; the method comprising: moving the one or more waste objects towards the working area with a conveyor; and rotating at least a portion of the manipulator with respect to the frame such that the gripper is moved lengthways along the conveyor within the working area. 
     In a third aspect of the invention there is provided a waste sorting robot comprising: a frame having a beam extending over a working area; a manipulator moveably mounted to the beam and comprising a gripper for interacting with one or more waste objects to be sorted within a working area; and a conveyor for moving the one or more waste objects towards the working area; wherein at least a portion of the manipulator or the cross beam is rotatable such that the gripper is moveable lengthways along the conveyor within the working area. 
     In a fourth aspect of the invention there is provided a waste sorting robot comprising: a frame; a manipulator moveably mounted to the frame and comprising a gripper for interacting with one or more waste objects to be sorted within a working area; and a conveyor for moving the one or more waste objects towards the working area; characterised in that the frame comprises a fixed cross beam arranged over the conveyor and the manipulator is slidable along the cross-beam; wherein at least a portion of the manipulator is rotatable with respect to a longitudinal axis of the cross beam perpendicular to a longitudinal axis of the conveyor such that the gripper is moveable lengthways along the longitudinal axis of the conveyor within the working area. 
    
    
     
       Various other aspects and further examples are also described in the following detailed description and in the attached claims with reference to the accompanying drawings, in which: 
         FIG.  1    shows a perspective schematic view of the waste sorting robot according to an example; 
         FIG.  2    shows a close-up perspective schematic view of a manipulator of the waste sorting robot according to an example; 
         FIG.  3    shows a schematic view of the waste sorting robot and manipulator according to an example; 
         FIG.  4    shows another close-up perspective schematic view of a manipulator of the waste sorting robot according to an example; 
         FIG.  5    shows a perspective view of a plurality of manipulators of the waste sorting robot according to an example; 
         FIG.  6    shows another perspective view of a plurality of manipulators of the waste sorting robot according to an example; 
         FIG.  7    shows a cross-sectional view of a manipulator of the waste sorting robot according to an example; and 
         FIG.  8    shows a cross-sectional view of a manipulator of the waste sorting robot according to another example. 
     
    
    
       FIG.  1    shows a schematic perspective view of a waste sorting robot  100 . In some examples, the waste sorting robot  100  can be a waste sorting gantry robot  100 . In other examples other types of waste sorting robots can be used such as delta robots. For the purposes of brevity, the examples will be described in reference to waste sorting gantry robots but can also be other types of robot such as robot arms or delta robots. Alternatively, the waste sorting robot is a SCARA robot which has a rotary joint that moves the manipulator along the travelling direction of the belt. 
     For the purposes of brevity, the examples will be described in reference to waste sorting gantry robots  100 , but any of the other aforementioned robot types can be used instead or in addition to the waste sorting gantry robot  100 . 
     The waste sorting gantry robot comprises a controller  102  for sending control and movement instructions to a manipulator  104  for interacting with the physical objects  106   a,    106   b,    106   c . The combination of a controller sending control instructions to a manipulator can also be referred to as a “robot”. The controller  102  is located remote from the manipulator  104  and is housed in a cabinet (not shown). In other examples, the controller  102  can be integral with the manipulator and/or a gantry frame  120 . 
     The manipulator  104  physically engages and moves the objects  106   a,    106   b,    106   c  that enters the working area  108 . The working area  108  of a manipulator  104  is an area within which the manipulator  104  is able to reach and interact with the object  106   a    106   b,    106   c.  The working area  108  as shown in  FIG.  1    is projected onto a conveyor belt  110  for the purposes of clarity. The manipulator  104  is configured to move at variable heights above the working area  108 . In this way, the manipulator  104  is configured to move within a working volume defined by the height above the working area  108  where the robot can manipulate an object. The manipulator  104  comprises one or more components for effecting relative movement with respect to the objects  106   a,    106   b,    106   c.  The manipulator  104  will be described in further detail below. 
     The physical objects  106   a,    106   b,    106   c  are moved into the working area  108  by the conveyor belt  110 . The path of travel of the conveyor belt  110  intersects with at least a portion of the working area  108 . In some examples, manipulator  104  can move over the entire working area  108 . In other examples, the manipulator  104  can move through a portion of the working area  108  and a plurality of waste sorting robots  100  operate within the working area  108 . For example, two waste sorting robots  100  can cover the entire conveyor belt  110 . This means that every object  106   a,    106   b,    106   c  that is moving on the conveyor belt  110  will pass through the working area  108 . The conveyor belt  110  can be a continuous belt, or a conveyor belt formed from overlapping portions. The conveyor belt  110  can be a single belt or alternatively a plurality of adjacent moving belts. 
     In other examples, the physical objects  106   a,    106   b,    106   c  can be conveyed into the working area  108  via other conveying means. The conveyor can be any suitable means for moving the objects  106   a,    106   b,    106   c  into the working area  108 . For example, the objects  106   a,    106   b ,  106   c  are fed under gravity via slide (not shown) to the working area  108 . In other examples, the objects can be entrained in a fluid flow, such as air or water, which passes through the working area  108 . 
     The direction of the conveyor belt  110  is shown in  FIG.  1    by two arrows. The objects  106   a , and  106   b  are representative of different types of objects to be sorted having not yet been physically engaged by the manipulator  104 . In contrast, the object  106   c  is an object that has been sorted into a particular type of object. In some examples, the manipulator  104  interacts with only some of the objects  106   c.  For example, the waste sorting gantry robot  100  is only removing a particular type of object. In other scenarios, the manipulator  104  will interact and sort every object  106   a,    106   b,    106   c  which is on the conveyor belt  110 . 
     In some examples, the objects to be sorted are waste products. The waste products can be any type of industrial, commercial, domestic waste or any other waste which requires sorting and processing. Unsorted waste material comprises a plurality of fractions of different types of waste. Industrial waste can comprise fractions, for example, of metal, wood, plastic, hardcore and one or more other types of waste. In other examples, the waste can comprise any number of different fractions of waste formed from any type or parameter of waste. The fractions can be further subdivided into more refined categories. For example, metal can be separated into steel, iron, aluminium etc. Domestic waste also comprises different fractions of waste such as plastic, paper, cardboard, metal, glass and/or organic waste. 
     A fraction is a category of waste that the waste can be sorted into by the waste sorting gantry robot  100 . A fraction can be a standard or homogenous composition of material, such as aluminium, but alternatively a fraction can be a category of waste defined by a customer or user. 
     In some examples, the waste can be sorted according to any parameter. A non-limiting list of parameters for dividing unsorted waste into fractions is as follows: material, previous purpose, size, weight, colour, opacity, economic value, purity, combustibility, whether the objects are ferrous or any other variable associated with waste objects. In a further example, a fraction can comprise one or more other fractions. For example, one fraction can comprise a paper fraction, a cardboard fraction, and a wood fraction to be combinable to be a combustible fraction. In other examples, a fraction can be defined based on the previous purpose of the waste object, for example plastic tubes used for silicone sealant. It may be desirable to separate out some waste objects because they are contaminated and cannot be recycled. 
     The objects are fed from a hopper or other stored source of objects onto the conveyor belt  110 . Alternatively, the waste objects are fed from another conveyor belt (not shown) and there is no source of stored waste objects. In this case, the additional conveyor belt can be fed manually from e.g. an excavator. Optionally, the objects  106   a,    106   b,    106   c  can be pre-processed before being placed on the conveyor belt. For example, the objects can be washed, screened, crushed, ripped, shaken, vibrated to prepare the material before sorting. Alternatively, the waste objects  106   a,    106   b,    106   c  can be sorted with another robot or mechanical device. The objects  106   a,    106   b,    106   c  can be optionally pre-sorted before being placed on the conveyor belt  110 . For example, ferrous material can be removed from the unsorted waste by passing a magnet in proximity to the conveyor belt  110 . Large objects can be broken down into pieces of material which are of a suitable size and weight to be gripped by the manipulator  104 . 
     The manipulator  104  is configured to move within the working volume. The manipulator  104  comprises one or more drive mechanisms  112 ,  114 ,  116  for moving the manipulator  104  in one or more axes. The drive mechanisms  112 ,  114 ,  116  can be servos, pneumatic actuators, rack and pinion mechanisms, belt drives or any other suitable means for moving the manipulator  104  in one or more directions. In some examples, the manipulator  104  comprises one or more servos for moving the manipulator  104  in one or more axes. In some other examples, the manipulator  104  comprises one or more pneumatic actuators for moving the manipulator  104  in one or more axes. In some further examples, the manipulator  104  comprises a combination of one or more servos and one or more pneumatic actuators for moving the manipulator  104  in one or more axes. In some examples, the manipulator  104  is moveable along a plurality of axes. 
     In some examples, the manipulator  104  is moveable along three axes which are substantially at right angles to each other. For example as shown in  FIG.  1   , the manipulator  104  is movable in an X-axis which is parallel with the longitudinal axis of the conveyor belt  110  (“beltwise” or “lengthways”). Additionally, the manipulator  104  is movable across the conveyor belt  110  in a Y-axis which is perpendicular to the longitudinal axis of the conveyor belt  110  (“widthwise”). The manipulator  104  is also movable in a Z-axis which is in a direction normal to the working area  108  and the conveyor belt  110  (“heightwise”). Optionally, the manipulator  104  can rotate about one or more axes. In some examples a suction gripper  132  or other suitable gripper coupled to the manipulator  104  can rotate about a W-axis. The suction gripper  132  or other suitable gripper is discussed in further detail below. 
     The directions of movement of the manipulator  104  within the working space along the X-axis, Y-axis and the Z-axis are shown by the two headed arrows with dotted lines in  FIG.  1   . The manipulator  104  is moved with respect to the conveyor belt  110  by an X-axis drive mechanism  112 , a Y-axis drive mechanism  114  and a Z-axis drive mechanism  116  respectively along the X-axis, the Y-axis and the Z-axis. The X-axis, Y-axis and Z-axis drive mechanisms  112 ,  114 ,  116  are connected to the controller  102  and the controller  102  is configured to issue instructions for actuating one or more X-axis, Y-axis and Z-axis drive mechanisms  112 ,  114 ,  116  to move the manipulator  104  within the working space  108 . The connections between the X-axis, Y-axis and Z-axis drive mechanisms  112 ,  114 ,  116  and the controller  102  are represented by dotted lines. Each connection between the X-axis, Y-axis and Z-axis drive mechanisms  112 ,  114 ,  116  and the controller  102  can comprises one or more data and/or power connections. 
     The X-axis, Y-axis and Z-axis drive mechanisms  112 ,  114 ,  116  for moving the manipulator  104  will be discussed in further detail with respect to  FIGS.  2  to  7   . 
     As shown in  FIG.  1   , the manipulator  104  is mounted on a frame  120 . In some examples, the frame  120  can be a gantry frame  120 . In other examples, the frame  120  can be other structures suitable for supporting the manipulator  104  above the working area  108 . For example, the frame  120  can be a structure for suspending the manipulator  104  above the working area  108  with rods and/or cables from a ceiling, wall or other structure. Hereinafter, the frame  120  will be referred to a gantry frame  120  but can be applicable to other frames for supporting the manipulator  104 . 
     The gantry frame  120  comprises vertical struts  122  which engage with the floor or another substantially horizontal surface. In some examples, the vertical struts  122  can be tilted upright struts. In this way, the tilted upright struts are angled to the vertical. The tilted upright struts may be required to mount the gantry frame  120  to the floor in a non-standard installation.  FIG.  1    shows the gantry frame  120  comprising four vertical struts  122  coupled together by horizontal beams  124 . In other examples, the horizontal beams  124  can be tilted lateral beams  124 . This may be required if the waste sorting gantry robot  100  is being installed in a small or unusual space. In other examples, there can be any suitable number of vertical struts  122 . The beams  124  and struts  122  are fixed together with welds, bolts or other suitable fasteners. Whilst the horizontal beams  124  are shown in  FIG.  1    to be located above the conveyor belt  110 , one or more horizontal beams  124  can be positioned at different heights. For example, one or more horizontal beams  124  can be positioned underneath the conveyor belt  110 . This can lower the centre of mass of the gantry frame  120  and make the entire waste sorting gantry robot  100  more stable if the vertical struts  122  are not secured to the floor. 
     The beams  124  and the struts  122  are load bearing and support the weight of the manipulator  104  and an object  106   a,    106   b,    106   c  that the manipulator  104  grasps. In some examples, the beams  124  and struts  122  are made from steel but other stiff, lightweight materials such as aluminium can be used. The vertical struts  122  can each comprise feet  126  comprising a plate through which bolts (not shown) can be threaded for securing the struts  122  to the floor. For the purposes of clarity, only one foot  126  is shown in  FIG.  1   , but each strut  122  can comprise a foot  126 . In other examples, there are no feet  126  or fasteners for securing the gantry frame  120  to the floor. In this case, the gantry frame rests on the floor and the frictional forces between the gantry frame and the floor are sufficient to prevent the waste sorting gantry robot from moving with respect to the floor. 
     In some examples as shown in  FIGS.  1  and  2   , the horizontal beam  128  is fixed with respect to the gantry frame  120 . This is in contrast to previously known waste sorting gantry robots because there is no servo mounted on the frame for moving the horizontal beam  128  in the X axis. Instead, the X-axis drive mechanism  112  for causing movement of the manipulator  104  in the X-axis is mounted to the horizontal beam  128  as discussed in reference to  FIG.  2    below. 
     This means that the waste sorting gantry frame robot  100  only needs to provide a single horizontal beam  128  across the conveyor belt  110  reducing the weight and complexity of the waste sorting robot  100 . This is because the gantry frame  120  of the waste sorting gantry frame robot  100  does not need to allow movement of the manipulator  104  mounted on a horizontal beam with an X-axis servo. By reducing the complexity of the gantry frame  120 , this means that installation of the waste sorting gantry frame robot  120  on a picking line is simplified and can be achieved by a single person. 
     By using a suction gripper  132  which pivots with respect to the horizontal beam  128  (rather than using an X-axis servo to move the horizontal beam  128 ), the mass of the manipulator  104  can be greatly reduced. Movement of the horizontal beam  128  or the manipulator  104  can be achieved with a limited angular movement. This means the inertia of the manipulator  104  is reduced and the manipulator  104  can be accelerated more quickly. This means that the manipulator  104  can move faster and the speed of the conveyor belt  110  can be increased. Advantageously, by increasing the speed of the conveyor belt  110 , the objects to be sorted on the conveyor belt  110  are more singularized and less likely to be overlapping. This means that the manipulation and object recognition is easier. This increases the processing rate (e.g. tons/hour) because the number of objects per hour which is fed to the robot increases. 
     This means that the waste sorting robot  100  is suitable for a working area  108  with a limited available distance in the X-axis but scalable in the Y-axis. Furthermore, the particular arrangement is advantageous for a waste sorting robot  100 . This is because a high precision of movement of the manipulator  104  similar to conventional robotics (e.g. &lt;1 mm) is not required. This is because the waste objects deform or move on the conveyor belt  110  and waste objects are successfully picked with the waste sorting robot discussed in reference to the Figures. Accordingly simple and lightweight materials can be used which provide a manipulator  104  that is faster moving than conventional waste sorting gantry robots. The lightweight materials of the waste sorting robot  100  are advantageously low cost. 
     Since the waste sorting robot  100  takes up a small space along the conveyor belt  110  in the Y-axis direction, a large work volume can be achieved with multiple waste sorting robots  100  sequentially positioned along the conveyor belt  110 . 
     However, additionally or alternatively, the manipulator  104  optionally comprises at least one movable horizontal beam  128  which is movably mounted on the gantry frame  120 . The moveable beam  128  can be mounted in a beam carriage (not shown). The moveable horizontal beam  128  is movably mounted on one or more of the other fixed horizontal beams  124  of the gantry frame  120 . 
     For example, the horizontal beam  128  is optionally rotatable about the longitudinal axis (A-A) of the horizontal beam  128 . In this way, when the horizontal beam  128  rotates, the manipulator  104  moves in the X axis. This is discussed in further detail with respect to  FIGS.  4  and  7   . 
     Turning back to  FIG.  2   , the example of at least part of the manipulator  104  being pivotally mounted on the horizontal beam  128  will be discussed in further detail. The manipulator  104  is coupled via a manipulator carriage  130  to a fixed horizontal beam  128 . The manipulator carriage  130  is coupled to a gripper assembly  132  for picking the waste objects  106   a,    106   b ,  106   c.  The manipulator carriage  130  is moveable along the longitudinal axis of the horizontal beam  128 . 
     Movement of the manipulator  104  in the Y-axis and Z-axis will now be discussed in further detail with reference to  FIGS.  1  and  2   . Movement of the manipulator in the X-axis will be discussed in further detail below. The manipulator carriage  130  is movable in the Y-axis relative to the horizontal beam  128 . In some examples, the manipulator carriage  130  comprises a Y-axis drive mechanism  114  for moving the manipulator carriage  130  along the Y-axis. In some examples, the Y-axis drive mechanism  114  is a servo. 
     In other examples, the Y-axis drive mechanism  114  is not mounted in the manipulator carriage  130  and manipulator carriage  130  moves with respect to the Y-axis drive mechanism  114 . In some examples, the Y-axis drive mechanism  114  is coupled to the horizontal beam  128  via a belt drive. In other examples, the Y-axis drive mechanism  114  is a servo which is coupled to the horizontal beam  128  via a rack and pinion mechanism. In some examples, other mechanisms can be used to actuate movement of the horizontal beam  128  along the Y-axis. For example, a hydraulic or pneumatic system can be used for moving the manipulator carriage  130 . 
     When the manipulator carriage  130  moves along the Y-axis, the suction gripper  132  also moves in the Y-axis. The suction gripper  132  is movably mounted to the manipulator carriage  130 . The suction gripper  132  is movable in the Z-axis in order to move the manipulator  104  heightwise in the Z-axis direction. 
     In some examples, the suction gripper  132  comprises a Z-axis drive mechanism  116  for moving the suction gripper  132  along the Z-axis. In some examples, the Z-axis drive mechanism is a pneumatic actuator  116 . In other examples, the Z-axis drive mechanism  116  is a Z-axis servo. Accordingly, when the Z-axis drive mechanism  116  is actuated and extends the suction gripper  132 , the suction gripper  132  moves towards the conveyor belt  110 . 
       FIGS.  1  and  2    show an example suction gripper  132  which will now be discussed. The suction gripper  132  can be a suction gripper having a suction cup  200  for gripping the objects using negative pressure with respect to atmospheric pressure. The suction gripper  132  is part of a suction gripper assembly  132  comprising one or more components for actuating or moving the suction gripper  132 . For the purposes of clarity, reference will only be made to the suction gripper  132 . The suction gripper  132  can have a suction cup ( 212  in  FIG.  2   ) which is substantially symmetric about the Z-axis. 
     This means that the suction gripper  132  does not need to be rotated about the Z-axis to achieve an optimal orientation with respect to the objects  106   a,    106   b,    106   c.  This means that the gripper assembly rotation servo is not required with a suction gripper  132 . In the case with an asymmetrical suction gripper  132 , the suction gripper  132  comprises a rotation servo or other actuator such as a pneumatic actuator (not shown) to rotate the suction gripper  132  about the W-axis as previously discussed above. Rotation of the suction gripper  132  about the W-axis is shown in  FIG.  1   , but the servo for causing the rotation is not shown. The suction gripper  132  can have an elongate suction cup  212 . Additionally or alternatively, the suction gripper  132  can comprise a plurality of suction grippers. For example, the suction gripper  132  can comprise an asymmetrical suction gripper  132  comprising two suction tubes each with a suction cup. 
     In other examples, the suction gripper  132  of the manipulator  104  additionally or alternatively comprises any suitable means for physically engaging and moving the objects  106   a,    106   b ,  106   c.  Indeed, the manipulator  104  can additionally or alternatively be one or more tools for grasping, securing, gripping, cutting or skewering objects. For example, the gripper assembly  132  is a pair of gripping jaws, a finger gripper or any magic gripper. In this way, the manipulator  104  can comprise a gripper which is not a suction gripper. In further examples the manipulator  104  can additionally be a tool configured for interacting with and moving an object at a distance such as an electromagnet or a nozzle for blowing compressed air. 
     As mentioned previously, the controller  102  is configured to send instructions to the X-axis, Y-axis and Z-axis drive mechanisms  112 ,  114 ,  116  of the manipulator  104  to control and interact with objects  106   a,    106   b,    106   c  on the conveyor belt  110 . The controller  102  is connected to at least one sensor  134  for detecting the objects  106   a,    106   b,    106   c  on the conveyor belt  110 . The at least one sensor  134  is positioned in front of the manipulator  104  so that detected measurements of the objects  106   a,    106   b,    106   c  are sent to the controller  102  before the objects  106   a,    106   b,    106   c  enter the working area  108 . In some examples, the at least one sensor  134  can be one or more of a RGB camera, an infrared camera, a metal detector, a hall sensor, a temperature sensor, visual and/or infrared spectroscopic detector,  3 D imaging sensor, terahertz imaging system, radioactivity sensor and/or a laser. The at least one sensor  134  can be any sensor suitable for determining a parameter of the object  106   a,    106   b,    106   c.    
       FIG.  1    shows that the at least one sensor  134  is positioned in one position. The at least one sensor  134  is mounted in a sensor housing  136  to protect the sensor  134 . In other examples, a plurality of sensors are positions along and around the conveyor belt  110  to receive parameter data of the objects  106   a,    106   b,    106   c.  In some examples, the at least one sensor  134  is mounted in a sensor bar  500  (as shown in  FIG.  5   ) which is positioned in front of the manipulator  104  on the conveyor belt  110 . In this way, the sensor bar  500  detects the objects  106   a,    106   b,    106   c  to be sorted before the objects  106   a,    106   b,    106   c  enter the working area  108 . 
     The controller  102  receives information from the at least one sensor  134  corresponding to one or more objects  106   a,    106   b,    106   c  on the conveyor belt  110 . The controller  102  determines instructions for moving the manipulator  104  based on the received information according to one or more criteria. Various information processing techniques can be adopted by the controller  102  for controlling the manipulator  104 . Such information processing techniques are described in WO2012/089928, WO2012/052615, WO2011/161304, WO2008/102052 which are incorporated herein by reference. The control of the waste sorting robot  100  is discussed in further detail in reference to  FIG.  3    below. 
     Once the manipulator  104  has received instructions from the controller  102 , the manipulator  104  executes the commands and moves the suction gripper  132  to pick an object  106   c  from the conveyor belt  110 . The process of selecting and manipulating an object on the conveyor belt  110  is known as a “pick”. 
     Once a pick has been completed, the manipulator  104  drops or throws the object  106   c  into a chute  138 . An object  106   c  dropped into the chute  138  is considered to be a successful pick. A successful pick is one where an object  106   c  was selected and moved to the chute  138  associated with the same fraction of waste as the object  106   c.    
     The chute  138  comprises a chute opening  142  in the working area  108  for dropping picked objects  106   c.  The chute opening  142  of the chute  138  is adjacent to the conveyor belt  110  so that the manipulator  104  does not have to travel far when conveying a picked object  106   c  from the conveyor belt  110  to the chute opening  142 . By positioning the chute opening  142  of the chute adjacent to the conveyor belt  110 , the manipulator  104  can throw, drop, pull and/or push the object  106   c  into the chute  138 . 
     The chute  138  comprises walls  140  defining a conduit for guiding picked objects  106   c  into a fraction receptacle (not shown) for receiving a sorted fraction of waste. In some examples, a fraction receptacle is not required and the sorted fractions of waste are piled up beneath the chute  138 .  FIG.  1    only shows one chute  138  associated with the manipulator  104 . In other examples, there can be a plurality of chutes  138  and associated openings  142  located around the conveyor belt  110 . Each opening  142  of the different chutes  138  is located within the working area  108  of the manipulator  104 . The walls  140  of the conduit can be any shape, size or orientation to guide picked objects  106   c  to the fraction receptacle. In some examples, the successfully picked objects  106   c  move under the force of gravity from the chute opening  142  of the chute  138  to the fraction receptacle. In other examples, the chute  138  may guide the successfully picked objects  106   c  to another conveyor belt (not shown) or other means for moving the successfully picked objects  106   c  to the fraction receptacle. 
     Turning back to  FIG.  2   , the movement of the manipulator  104  in the X-axis will be discussed in further detail.  FIG.  2    shows a close-up perspective schematic view of a manipulator of the waste sorting robot according to an example. The movement of the manipulator  104  in the orthogonal X-axis, Y-axis, Z-axis is illustrated with two headed arrows in  FIG.  2   . 
     The working area  108  has been indicated with a rectangle with a dotted line. The conveyor belt  110  has not been shown in  FIG.  2    for the purposes of clarity. 
     The manipulator  104  comprises a manipulator carriage  130  which is slidably moveable on the horizontal beam  128 . The manipulator carriage  130  and the horizontal beam  128  is the same as discussed with reference to  FIG.  1   . Movement of the manipulator carriage  130  causes movement of the manipulator  104  in the Y-axis as previously discussed. 
     The manipulator  104  is rotatable with respect to the horizontal beam  128 . The manipulator  104  is arranged to rotate within a plane substantially perpendicular to the plane of the conveyor belt  110 . This is illustrated in  FIG.  2    with the arc  200  showing the limits of the movement of the manipulator  104 . 
     In some examples, at least a portion of the manipulator  104  is pivotally mounted on the manipulator carriage  130 . The manipulator carriage  130  comprises a yoke  202  having a first arm  204  and a second arm  206 . The yoke  202  provides a pivot point  208  for a pin (not shown) which is threaded through an upper portion  210  of the suction gripper  132 . The pivot point  208  allows the suction gripper  132  to pivot about the axis B-B. The axis B-B is substantially parallel with the horizontal beam  128 . 
     In other examples the axis B-B is not parallel with the horizontal beam  128 . This means that pivoting of the manipulator  104  about the axis B-B will cause movement of the suction gripper  132  in both the X-axis and the Y-axis. 
     In some examples, the manipulator  104  is pivotally mounted directly on the horizontal beam  128  and there is no manipulator carriage  130 . In this case, the horizontal beam  128  is moveable with respect to the frame  120  and the horizontal beam  128  slides along the longitudinal axis A-A of the horizontal beam  128  in order to cause the manipulator  104  to move in the Y-axis. 
     The upper portion  210  of the suction gripper  132  comprises a Z-axis pneumatic actuator  116  (not shown in  FIG.  2    for the purposes of clarity) for moving the lower portion  214  of the suction gripper  132  in the Z-axis. In this way, the Z-axis pneumatic actuation  116  adjusts the height of the suction cup  212  above the conveyor belt  110  as previously discussed. 
     An X-axis drive mechanism  112  is coupled between the manipulator carriage  130  and the upper portion  210  of the suction gripper  132 . In some examples, the X-axis drive mechanism  112  is a first pneumatic actuator  306 . In other examples, the X-axis drive mechanism  112  can be any suitable mechanism for causing the suction gripper  132  to pivot about the horizontal beam  128  such as a linkage or a rack and pinion mechanism. 
     This means that the suction gripper  132  can be moved in the X-axis by extension or retraction of the first pneumatic actuator  306  which causes rotation about the B-B axis. The extension/retraction of the first pneumatic actuator  306  causes at least a portion of the manipulator  104  to pivot about the B-B axis. Accordingly, the suction gripper  132  moves in an arc  200  which moves the suction gripper  132  in the X-axis lengthways along the conveyor within the working area  108 . The arc  200  of travel of the suction gripper  132  is shown in  FIG.  2   . 
     The suction gripper  132  will rotate about the B-B axis however this does not affect the functionality of the suction gripper  132  because the rotation of the suction gripper  132  with respect to the conveyor belt  110  is not particularly great. Furthermore, the suction cup  212  is flexible to compensate for the irregular shapes of the waste objects  106   a,    106   b,    106   c  on the conveyor. Therefore, the suction cup  212  can still pick objects  106   a,    106   b,    106   c  on the conveyor  110  even when the manipulator  104  is rotated about the axis B-B. In some examples, the suction gripper  132  rotates about the B-B axis with a rotation between  10  to  20  degrees. This allows the suction gripper  132  to successfully pick waste objects within the working area  108  whilst not requiring the manipulator  104  or the suction gripper  132  to be separately rotated to be exactly vertical. Advantageously, this means that the manipulator  104  can remain lightweight and not require additional actuators and linkages to ensure that the suction gripper  132  remains vertical. 
     In some alternative examples, the manipulator  104  comprises further articulations in addition to the pivot point  208 . For example, the manipulator  104  comprises two or three pivotable joints. In this case, the suction gripper  132  can be kept vertical. For each additional articulation, an additional pneumatic cylinder is provided. 
     Advantageously, this means that the waste sorting gantry frame robot  100  only needs to provide a single horizontal beam  128  across the conveyor belt  110  reducing the weight and complexity of the waste sorting robot  100 . This is because the gantry frame  120  of the waste sorting gantry frame robot  100  does not need to allow movement of the manipulator  104  mounted on a horizontal beam with an X-axis servo. By reducing the complexity of the gantry frame  120 , this means that installation of the waste sorting gantry frame robot  120  on a picking line is simplified and can be achieved by a single person. 
     Advantageously, by using a suction gripper  132  which pivots with respect to the horizontal beam  128  (rather than using an X-axis servo to move the horizontal beam  128 ), the mass of the manipulator  104  can be greatly reduced. This means the inertia of the manipulator  104  is reduced and the manipulator  104  can be accelerated quickly. This means that the manipulator  104  can move faster and the speed of the conveyor belt  110  can be increased. 
     Advantageously, by increasing the speed of the conveyor belt  110 , the objects to be sorted on the conveyor belt  110  are more singularized and less likely to be overlapping. This means that the manipulation and object recognition is easier. This increases the processing rate (e.g. tons/hour) because the number of objects per hour which is fed to the robot increases. 
     The control of the waste sorting robot  100  will now be discussed in further detail with reference to  FIG.  3   .  FIG.  3    shows a schematic view of the waste sorting robot  100  and manipulator  104  according to an example discussed in reference to any of the other examples. 
     As mentioned, the X-axis drive mechanism  112  and the Z-axis drive mechanism  116  respectively comprise first and second pneumatic actuators  306 ,  308  for respectively causing the movement of the manipulator  104  in the X-axis and Z-axis. By using the first and second pneumatic actuators  306 ,  308  to move the manipulator  104 , the waste sorting robot  100  can be made lighter than compared to a waste sorting robot  100  using servos for moving the manipulator  104 . Again this reduces the mass and inertia of the manipulator  104  and can increase the speed of the waste sorting robot  100 . 
       FIG.  3    shows a suction gripper  132  which is in fluid communication with a pneumatic system  300 . The pneumatic system  300  comprises at least one hose  304  for connecting the suction gripper  132  to the pneumatic system  300 . In some embodiments, the hose is an air hose  304  for providing a source of air to the suction gripper  132 . 
     Furthermore, the first pneumatic actuator  306  is in fluid communication with the pneumatic system  300 . The pneumatic system  300  comprises at least one hose  310  for connecting the first pneumatic actuator  306  to the pneumatic system  300 . Likewise, the second pneumatic actuator  308  is in fluid communication with the pneumatic system  300 . The pneumatic system  300  comprises at least one hose  310  for connecting the second pneumatic actuator  306  to the pneumatic system  300 . 
     The air hoses  304 ,  310 ,  312  are flexible and threaded along the horizontal beam  128  and connected to pneumatic system  300 . In some embodiments, (not shown) the air hoses  304 ,  310 ,  312  can be inserted within the hollow horizontal beam  128 . The hoses  304 ,  310 ,  312  are sufficiently flexible to move and flex so as to change shape as the manipulator  104  moves without impeding the movement of the manipulator  104 . 
     The pneumatic system  300  can comprise an air compressor for generating a source of compressed air. Optionally, the pneumatic system  300  can also comprise an air storage tank (not shown) for compressed air. Furthermore, the pneumatic system  300  can also comprise one or more valves  302  for selectively providing air to the suction gripper  132 , the first pneumatic actuator  306 , and/or the second pneumatic actuator  308 . In some embodiments, the air compressor generates an air source having a pressure of 8 Bar. In other embodiments, the air source has a pressure of 5 Bar to 10 Bar. In other embodiments, the air source can have any suitable pressure above atmospheric pressure. 
     The pneumatic system  300  can be partially or wholly located remote from the waste sorting robot  100 . For example, there may be a plurality of waste sorting robots  100  on a sorting line (not shown) each of which require a source of air. In this way, a single air compressor can be connected to a plurality of waste sorting robots  100  via a plurality of air hoses  304 ,  310 ,  312 . 
     Accordingly, the pneumatic system  300  may be located between waste sorting robots  100 . 
     In some examples, waste sorting robot  100  comprises a suction gripper sensor  314  for detecting relative movement of the suction gripper  132  or the manipulator  104  in the X-axis. The suction gripper sensor  314  is mounted on the suction gripper  132 , or the manipulator  104  and connected to the controller  102 . In this way, the suction gripper sensor  314  is configured to detect the rotational movement of the suction gripper  132  as the suction gripper  132  pivots about the axis B-B in  FIG.  2   . Alternatively, the suction gripper sensor  314  is configured to detect the rotational movement of the moveable horizontal beam  128  about the A-A axis as shown in  FIG.  4   . The example as shown in  FIG.  4    will be discussed in further detail below. 
     In some examples, the suction gripper sensor  314  is a gyroscopic sensor, such as an electrical MEMS gyroscope is used as a velocity sensor. This means that the controller  102  can determine the velocity of the suction gripper  132  during operation in order to make the control of the suction gripper  132  more accurate. Additionally or alternatively, the first pneumatic actuator  306  of the X-axis drive mechanism  112  and/or the second pneumatic actuator  308  of the Z-axis drive mechanism  116  comprise first and second pressure sensors  316 ,  318 . The first and second pressure sensors  316 ,  318  are mounted to the first and second pneumatic actuators  306 ,  308  such that the signal generated by the first and second pressure sensors  316 ,  318  indicates the extension of the first and second pneumatic actuators  306 ,  308 . The pressure sensors  316 ,  318  are connected to the controller  102 . Accordingly the controller  102  can determine the status of the first and second pneumatic actuators  306 ,  308 . 
     The signals received from the suction gripper sensor  314 , and the first and second pressure sensors  316 ,  318  are used as linear terms in the proportional integral derivative (PID) controller algorithm of the manipulator  104 . 
       FIG.  3    shows a schematic cross section of the waste sorting gantry robot  100 . Operation of the pneumatic system  300  is controlled by the controller  102 . This means that the controller  102  can selectively operate e.g. the air compressor or the valve  302  of the pneumatic system  300  to deliver a supply of air to the suction gripper  132 , the first pneumatic actuator  306  and/or the second pneumatic actuator  308 . In this way, the first pneumatic actuator  306 , the second pneumatic actuator  308  and/or the suction gripper  132  are connected to a single pneumatic system  300 . 
     During operation, the controller  102  controls the first pneumatic actuator  306  and/or the second pneumatic actuator  308  in order to move the suction gripper  132  in the Z-axis and rotate the suction gripper  132  about the B-B axis. 
     Movement of the first pneumatic actuator  306  and the amount of rotation of the suction gripper  132  about B-B axis is based on the position determined from signals received from one or more of the suction gripper sensor  314 , and the first and second pressure sensors  316 ,  318 . Accordingly, the controller  102  positions the suction gripper  132  in the X-axis having moved the suction gripper  132  in the Z-axis and rotated the suction gripper  132  about the B-B axis. 
     The controller  102  can detect if the suction gripper  132  touches an object  106   a,    106   b,    106   c  above the conveyor belt  110 . This means that the controller  102  can dynamically adjust the amount of rotation about the B-B axis and/or the amount of movement in the Z-axis so that the suction gripper  132  does not drag the object  106   a,    106   b,    106   c  along the conveyor belt  110 . In other words, the controller  102  can control the movement of the suction gripper  132  in the Z-axis and rotate the suction gripper  132  about the B-B axis to maintain the suction gripper  132  at a determined height above the conveyor belt  110  and not at the surface of the conveyor belt  110 . 
     Turning to  FIG.  4    another example will now be described.  FIG.  4    shows another close-up perspective schematic view of the manipulator  104  of the waste sorting robot according to an example.  FIG.  4    is the same as the waste sorting robot  100  as shown in  FIG.  2    except that the manipulator  104  does not rotate with respect to the horizontal beam  128 . The upper portion  210  of the suction gripper  132  is fixed to the manipulator carriage  130 . In this way, the suction gripper  132  does not pivot about the manipulator carriage  130 . 
     In contrast, the horizontal beam  128  is moveable and rotates about the longitudinal axis A-A of the horizontal beam  128 . This means that the manipulator  104  rotates about the axis A-A at the same time as the horizontal beam  128 . The manipulator carriage  130  is slidably mounted on the horizontal beam  128  but the manipulator carriage  130  is only permitted to slide along the horizontal beam  128 . Accordingly, there is no relative movement between the manipulator  104  and the horizontal beam  128  when the horizontal beam  128  rotates. 
     Similar to the example as discussed in reference to  FIG.  2   , when the horizontal beam  128  rotates, the suction gripper  132  and the suction cup  212  move along the X-axis. 
     The horizontal beam  128  is coupled to an X-axis drive mechanism  112  for rotating the horizontal beam  128  about the axis A-A. The X-axis drive mechanism  112  is a servo coupled to horizontal beam  128 . Alternatively, the horizontal beam  128  can be pivotally coupled to a pneumatic actuator (not shown). The X-axis drive mechanism  112  can be any suitable mechanism for causing the horizontal beam  128  to rotate. This is advantageous because the manipulator  104  can be made lighter since the pneumatic actuator is not mounted on the moving manipulator carriage  130 . The inertia of rotation of the horizontal beam  128  and the manipulator  104  does not increase significantly. 
       FIG.  5    shows a perspective view of a plurality of manipulators  502 ,  504  of the waste sorting robot  100  according to an example. The manipulators  502 ,  504  are the same as the manipulators  104  described in the examples in reference to any of the Figures. The manipulators  502 ,  504  are respectively mounted on horizontal beams  506 ,  508 . The horizontal beams  506 ,  508  are mounted to the gantry frame  120 . Since the manipulators  502 ,  504  are lighter and less bulky, they can be positioned closer together within the same gantry frame  120  without the manipulators  502 ,  504  colliding. This means that the manipulators  502 ,  504  can sort objects  106   a,    106   b,    106   c  in the same chutes,  510 ,  512 ,  514 ,  516 .  FIG.  5    shows that there are two chutes each side of the conveyor belt  110 . In other examples, there are between one and three chutes on each side of the conveyor belt  110 . In this way, each manipulator  502 ,  504  can feed sorted objects  106   c  into two chutes on each side of the conveyor belt  110 . In some examples, the working areas  108  of the manipulators  502 ,  504  can overlap, however, the controller  102  instructs the manipulators  502 ,  504  not to collide in the X-axis. 
     In further embodiments, there can be any number of manipulators  502 ,  504  positioned along the conveyor belt  110 . 
       FIG.  6    shows another perspective view of a plurality of manipulators  502 ,  504  of the waste sorting robot according to an example. The example shown in  FIG.  6    is the same as shown in  FIG.  5    except that the manipulators  502 ,  504  are mounted on the same horizontal beam  600 . 
       FIG.  7    shows a cross-sectional view of a manipulator  712  of the waste sorting robot  100  according to an example. The manipulator  712  comprises a plurality of pivoting linkages  700 ,  702 ,  704 ,  706  connected between the suction gripper  132  and the frame  710 . Actuation of the pivoting linkages  700 ,  702 ,  704 ,  706  is achieved via one or more pneumatic actuators (not shown). Movement of the pivoting linkages  700 ,  702 ,  704 ,  706  causes movement of the suction gripper  132  in both the Z and Y directions. In this way, the assembly of pivoting linkages  700 ,  702 ,  704 ,  706  is analogous to a two-dimensional delta robot. 
     The pivoting linkages  700 ,  702 ,  704 ,  706  are pivotally mounted to a frame  710 . The frame  710  is rotatable about an axis C-C. In some examples, the frame  710  is fixed to a rotating beam  714  which rotates in a similar way to the horizontal beam  128  described in  FIG.  4   . However, in some examples, the frame  710  is fixed to a wall or ceiling or another structure and the pivoting linkages  700 ,  702 ,  704 ,  706  pivot with respect to the frame  710  about axis C-C. 
     This means that when the pivoting linkages  700 ,  702 ,  704 ,  706  pivot with respect to the frame  710  or the frame  710  is rotates about axis C-C, the suction gripper  132  moves in the X-axis through the line D-D. 
     Another example will be discussed in reference to  FIG.  8   .  FIG.  8    shows a cross-sectional view of a manipulator  800  of the waste sorting robot  100  according to an example.  FIG.  8    shows a cross-section perpendicular to the cross-section shown in  FIG.  7   . The waste sorting robot  100  as shown in  FIG.  8    is the same as the waste sorting robot  100  shown in  FIG.  7    except that the pivoting linkages  800 ,  802 ,  804 ,  806  in  FIG.  8    are arranged to move the suction gripper  132  in a perpendicular plane to the pivoting linkages  700 ,  702 ,  704 ,  706  in  FIG.  7   . 
     The manipulator  800  comprises a plurality of pivoting linkages  800 ,  802 ,  804 ,  806  connected between the suction gripper  132  and the frame  710 . Actuation of the pivoting linkages  800 ,  802 ,  804 ,  806  is achieved via one or more pneumatic actuators (not shown) and is the same as discussed in reference to  FIG.  7   . Movement of the pivoting linkages  800 ,  802 ,  804 ,  806  causes movement of the suction gripper  132  in both the Z and X directions. In this way, the assembly of pivoting linkages  800 ,  802 ,  804 ,  806  is analogous to a two-dimensional delta robot. The example as shown in  FIG.  8    is the same as shown in  FIG.  7   , except that the pivoting linkages  800 ,  802 ,  804 ,  806  move in the plane comprising the X-axis and the Z-axis. 
     In contrast, the pivoting linkages  700 ,  702 ,  704 ,  706  described in  FIG.  7    move in the plane comprising the Y-axis and the Z-axis. 
     The pivoting linkages  800 ,  802 ,  804 ,  806  are pivotally mounted to a frame  710 . The manipulator  800  is moveable along the longitudinal axis C-C of the beam  814  in the same way as described in reference to  FIGS.  2  to  4   . 
     This means that when the pivoting linkages  800 ,  802 ,  804 ,  806  pivot with respect to the frame  710 , the suction gripper  132  moves in the X-axis along the length of the conveyor belt  110  within the working area  108 . 
     In other examples, the suction gripper arrangements and the operation of the suction grippers as discussed can also be used with other types of object manipulation robots. For example, the suction gripper  132  can be used with industrial robots in the automotive industry, food industry etc. In this the way the suction gripper and method of controlling the manipulator and suction gripper can be used with a sorting robot for sorting objects. 
     Optionally, in another example the moveable horizontal beam  128  is additionally movable in the X-axis such that the manipulator  104  moves in the X-axis when the movable horizontal beam moves in the X-axis similar to previously known gantry frame robots. The moveable horizontal beam  128  is mounted to the fixed horizontal beams  124  via an X-axis servo mechanism  112 . In some examples, the drive mechanism  112  is coupled to the moveable horizontal beam  128  via a belt drive. In other examples, the servo is coupled to the moveable horizontal beam  128  via a rack and pinion mechanism. In some examples, other mechanisms can be used to actuate movement of the moveable horizontal beam along the X-axis. For example, a hydraulic or pneumatic system can be used for moving the movable horizontal beam  128 . In this way, there are two different X-axis drive mechanisms  112  for moving the manipulator  104  in the X-axis. This example may be less preferred because one of the X-axis drive mechanisms  112  may be redundant. 
     In another example, two or more examples are combined. Features of one example can be combined with features of other examples. 
     Examples of the present invention have been discussed with particular reference to the examples illustrated. However it will be appreciated that variations and modifications may be made to the examples described within the scope of the invention.