Patent Description:
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".

One such robotic waste sorting system is a "delta" robot suspended over a conveyor belt which moves objects to be sorted. The conveyor belt passes under the delta robot and within a working area of the delta robot. A working area of a robot is an area on a surface within which the robot is able to reach and manipulate an object. A working volume is the physical space within which the robot is able to move and manipulate an object. The working volume is determined by the height above the working area where the robot can manipulate an object.

The working volume / area can also include chutes which are not part of the surface of a conveyor belt.

A delta robot comprises a servo housing and a plurality of arms which are connected to one or more servos for moving the arms. The arms extend down from the servo housing to a base which is coupled to a manipulator. The arms are connected via universal joints at the base.

Whilst a delta robot can be relatively effective at picking small light objects, the delta robot is not suitable for lifting heavy objects. Furthermore since the manipulator is suspended from the servo housing, the servos must have sufficient power to move the manipulator and the object. This means that the manipulators coupled to delta robots must be as light as possible to increase the maximum lift capacity of the delta robot.

Disadvantageously, the dimensions of the working volume for a delta robot varies across the width of the working space. In particular, the working volume is an inverted cone and becomes narrower as the manipulator moves away from the servo housing. In practice, this may mean that a delta robot cannot manipulate objects at the same height across the width of a conveyor belt and that delta robots are only suitable for working with narrow conveyor belts. This can be problematic because objects can be piled on each other making identifying and picking objects harder. This can limit the design choices and use applications when using a delta robot for waste sorting.

A delta robot is not particularly robust and the universal joints of a delta robot are particularly susceptible to wear and malfunction. Another consideration of a delta robot is that the movement of one or more arms causes movement in the other arms. Accordingly, whenever a delta robot moves, control instructions must be sent to each servo because each arm must move when the manipulator of the delta robot is moved. The non-linear control instructions to move the arms of the delta robot means that increased computational processing is required to control and move the delta robot within the working area / working volume.

Another 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.

It is known for automatic robotic sorting systems to use finger grippers or other articulated jaws for gripping objects to be sorted. A problem with finger grippers is that they have a specific plane in which the fingers or jaws close. This means that in order to successfully grip objects on a conveyor belt, the finger gripper or jaws must rotate. The rotation requires a rotation servo which increases the weight and complexity of the manipulator.

A known alternative gripper is a suction gripper which uses negative pressure with respect to atmospheric pressure for sucking and gripping an object to be sorted. Suction grippers can become blocked which can adversely affect performance. Manual visual inspection may be required to check whether the suction gripper is operating correctly when the suction gripper repeatedly fails to grip an object.

Accordingly, the waste sorting robot has a greater chance of making successful picks.

Embodiments of the present invention aim to address the aforementioned problems.

A waste sorting robot according to the present invention is defined in independent claim <NUM>. A corresponding method is defined in independent claim <NUM>.

Optionally, the waste sorting robot comprises at least one pressure sensor in fluid communication with the suction gripper and configured to generate a pressure signal in dependence on a fluid pressure in the suction gripper; at least one position sensor configured to generate a position signal in dependence of the position of the manipulator and / or the suction gripper; wherein the controller is configured to receive the pressure signal and the position signal and to determine manipulator instructions in dependence on the pressure signal and the position signal.

This means that the waste sorting robot can control the suction gripper and the manipulator in dependence of the pressure of the suction gripper. This means that the controller can adapt and react to differences in pressure at the suction gripper and become more reliable.

<CIT> discloses a transfer device for a work piece having controller and nozzles communicating with suction pump. The nozzles are movable with air cylinders. Nozzles are in contact with inner wall face of housing in the retracted position of air cylinders, thus preventing air flow through the nozzles. As air cylinder and nozzle moves downwards air may flow through inlet of nozzle. The nozzle may then be moved towards the workpiece.

<CIT> discloses a vacuum pressure information processing system having a vacuum unit. An operation start instruction signal is first input so that compressed air is introduced from a compressed-air feed source through an air feed port to produce a vacuum in ejector. Negative pressure is thus generated in a suction cup which attracts and holds a workpiece.

ITMI20081360A1 discloses a gripping head for bags of bulk material. Gripping member is connected to vacuum source. A sensor can indicate if vacuum is sufficient to pick up a bag.

<CIT> discloses a vacuum pick-up head with a plurality of suction cups for material handling.

<CIT> discloses a device for handling delicate samples of biological tissue. The force exerted by a vacuum cup on the biological material can be varied. A controller can calculate a difference between a measured or determined value and a target value and attempt to minimize that difference by adjusting operation of the variable suction source.

<CIT> discloses a robot gripper with fingers. A pneumatic member is used for sucking or blowing off an object. Air pressure of a cup can be detected by the pressure sensor.

<CIT> discloses a vacuum cup actuator for applying and releasing vacuum to a workpiece engaging a vacuum cup, where a housing provides a passageway for communicating vacuum to the vacuum cup.

<CIT> discloses an apparatus having an arm portion, a support plate, a plurality of expansion and contraction means, adsorption means, and a control unit. A suction pad of the adsorption means is connected to a pressure reducing means. The pressure reducing means reduces the pressure in the space between a work piece and the suction pad and makes the work piece adsorb the suction pad.

Optionally, the at least one pressure sensor is mounted on the suction gripper. This means that the pressure sensor is proximal to the suction gripper and the pressure at the suction gripper is precisely measured by the pressure sensor. Small variations in the pressure at the suction gripper can be measured accurately.

Optionally, the at least one pressure sensor is configured to measure the pressure in a suction cup of the suction gripper. In this way, the pressure sensor measures the lifting force of the suction gripper. The controller can adapt and react to changes in the determined lifting force of the suction gripper.

Optionally, the controller is configured to detect whether the pressure in the suction gripper is below a threshold suction pressure, the rate of change of the pressure rises above a threshold change rate, signal processing on the pressure signal, and / or filtering on the pressure signal. This means that the controller knows when a parameter the suction gripper has changed. Optionally, the controller determines a suction gripper status in dependence on the pressure signal.

Optionally, the controller determines a suction gripper status in dependence on a position of the manipulator and / or the suction gripper. The controller may determine a status of the suction gripper based on the position and the pressure of the suction gripper. In this way, the controller can distinguish between different suction gripper actions or statuses which have the same pressure magnitude or pressure profile. Optionally the controller may be connected to one or more sensors for determining the position of the manipulator and / or the suction gripper. Optionally the position sensor may be an encoder in a servo, a camera, a proximity sensor, an optical sensor, an infrared sensor, an ultrasound sensor, a laser distance sensor, a hall sensor, or any other suitable sensor for determining the position of the manipulator and / or the suction gripper.

Optionally, the controller determines suction gripper and / or manipulator instructions in dependence of the suction gripper status. Once the controller has determined what the suction gripper or the manipulator is currently doing, the controller can send instructions to control the suction gripper in response.

Optionally, the controller determines that the suction gripper status is one or more of the following: the suction gripper is blocked, an object has slipped off the suction gripper, the suction gripper has failed to grip an object, the suction gripper is gripping an object, based on the pressure information and / or the position of manipulator and / or the suction gripper. The controller can determine different situations of the suction gripper. The controller may determine other statuses of the suction gripper not listed above.

Optionally, the waste sorting robot comprises a valve coupled to the controller and for selectively controlling the direction of airflow through the suction gripper. This means that the controller can cause the suction gripper to suck or blow through the suction gripper. This means that the controller can selectively cause an object to be urged towards or away from the suction gripper.

Optionally, the controller is configured to select an operative valve mode of the valve in dependence on the pressure signal and / or the position of the manipulator. In this way, the controller can determine whether the suction gripper is normally operating or malfunctioning and take remedial action. Furthermore, the feedback from the pressure sensor is used by the controller to determine whether a pick has failed during a pick operation. This means that the controller can adapt and control the suction gripper and / or the manipulator more efficiently.

Optionally, the controller selects a blow valve mode to blow air through the suction gripper to unblock the suction gripper and / or to blow an object from suction gripper. This means that the controller can selectively use the direction of the airflow in the suction gripper to unblock the suction gripper.

Optionally, the suction gripper is slidably mounted on the manipulator. This means that the suction gripper can absorb some of the shock when the suction gripper engages an object. This increases the chances of a successful grip on an object and protects the manipulator from damage.

Optionally, the controller reverses the direction of the manipulator away from the working area in dependence on the pressure signal.

Optionally, the pressure signal comprises at least one of: a rate of change of the pressure in the suction cup, a magnitude of the pressure in the suction cup, a negative pressure value, and / or a positive pressure value.

Optionally, the at least one pressure sensor is one or more of the following: piezoelectric pressure sensor, electrostatic pressure sensor, piezoresistive pressure sensor, resonant pressure sensor, a pressure transducer, a Wheatstone bridge pressure transducer, a differential pressure transducer, a diaphragm pressure sensor, an inductive pressure sensor, a reluctive pressure sensor, or an optical pressure sensor.

Optionally, the controller varies the suction force generated by the suction gripper in dependence of the pressure signal. In this way, the controller can react to changes in the pressure signal to increase the chances of a successful grip. The controller can determine an increasing pressure in the suction cup and increase the suction force to ensure that an object does not slip off the suction gripper during a pick.

According to the invention, there is provided a waste sorting robot comprising: a manipulator comprising a suction gripper for interacting with one or more waste objects to be sorted within a working area, wherein the manipulator is moveable within the working area and wherein the suction gripper is moveable relative to the manipulator between a first position and a second position; a controller configured to send control instructions to the manipulator; and at least one sensor configured to detect the suction gripper moving between the first and second positions; wherein the controller is configured to actuate the suction gripper in dependence on a signal detecting the suction gripper has moved between the first and second positions.

This means that the air source is only used when the suction gripper engages an object. Engagement of the suction gripper and the object is determined by physical movement of the suction gripper with respect to the manipulator. Accordingly, the mechanical feedback is detected by the sensor and the controller controls the operation of the suction gripper accordingly.

Various other aspects and further embodiments are also described in the following detailed description and in the attached claims with reference to the accompanying drawings, in which:.

<FIG> shows a schematic perspective view of a waste sorting robot <NUM>. In some embodiments, the waste sorting robot <NUM> can be a waste sorting gantry robot <NUM>. In other embodiments other types of waste sorting robots can be used. For the purposes of brevity, the embodiments 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.

In some embodiments, the waste sorting robot <NUM> is a Selective Compliance Assembly Robot Arm (SCARA). The waste sorting SCARA <NUM> may move in the X, Y, and Z planes like the waste sorting gantry robot, but incorporate movement in a theta axis at the end of the Z plane to rotate the end-of-arm tooling e.g. the gripper assembly <NUM>. In some embodiments, the waste sorting robot <NUM> is a four axis SCARA robot <NUM> that consists of an inner link arm (not shown) that rotates about the Z-axis. The inner link arm is connected to an outer link arm (not shown) that rotates about a Z elbow joint (not shown). The Z elbow joint is connected to a wrist axis (not shown) that moves up and down and also rotates about Z. In some embodiments the waste sorting SCARA <NUM> comprises an alternative configuration which has the linear Z motion as the second axis.

For the purposes of brevity, the embodiments will be described in reference to waste sorting gantry robots <NUM>, but any of the other aforementioned robot types can be used instead or in addition to the water sorting gantry robot <NUM>.

The waste sorting gantry robot comprises a controller <NUM> for sending control and movement instructions to a manipulator <NUM> for interacting with the physical objects 106a, 106b, 106c. The combination of a controller sending control instructions to a manipulator can also be referred to as a "robot". The controller <NUM> is located remote from the manipulator <NUM> and is housed in a cabinet (as shown in <FIG>). In other embodiments, the controller <NUM> can be integral with the manipulator and / or a gantry frame <NUM>.

The manipulator <NUM> physically engages and moves the objects 106a, 106b, 106c that enters the working area <NUM>. The working area <NUM> of a manipulator <NUM> is an area within which the manipulator <NUM> is able to reach and interact with the object 106a 106b, 106c. The working area <NUM> as shown in <FIG> is projected onto a conveyor belt <NUM> for the purposes of clarity. The manipulator <NUM> is configured to move at variable heights above the working area <NUM>. In this way, the manipulator <NUM> is configured to move within a working volume defined by the height above the working area <NUM> where the robot can manipulate an object. The manipulator <NUM> comprises one or more components for effecting relative movement with respect to the objects 106a, 106b, 106c. The manipulator <NUM> will be described in further detail below.

The physical objects 106a, 106b, 106c are moved into the working area <NUM> by the conveyor belt <NUM>. The path of travel of the conveyor belt <NUM> intersects with at least a portion of the working area <NUM>. In some embodiments, manipulator <NUM> can move over the entire working area <NUM>. In other embodiments, the manipulator <NUM> can move through a portion of the working area <NUM> and a plurality of waste sorting robots <NUM> operate within the working area <NUM>. For example, two waste sorting robots <NUM> can cover the entire conveyor belt <NUM>. This means that every object 106a, 106b, 106c that is moving on the conveyor belt <NUM> will pass through the working area <NUM>. The conveyor belt <NUM> can be a continuous belt, or a conveyor belt formed from overlapping portions. The conveyor belt <NUM> can be a single belt or alternatively a plurality of adjacent moving belts.

In other embodiments, the physical objects 106a, 106b, 106c can be conveyed into the working area <NUM> via other conveying means. The conveyor can be any suitable means for moving the objects 106a, 106b, 106c into the working area <NUM>. For example, the objects 106a, 106b, 106c are fed under gravity via slide (not shown) to the working area <NUM>. In other embodiments, the objects can be entrained in a fluid flow, such as air or water, which passes through the working area <NUM>.

The direction of the conveyor belt <NUM> is shown in <FIG> by two arrows. The objects 106a, and 106b are representative of different types of objects to be sorted having not yet been physically engaged by the manipulator <NUM>. In contrast, the object 106c is an object that has been sorted into a particular type of object. In some embodiments, the manipulator <NUM> interacts with only some of the objects 106c. For example, the waste sorting gantry robot <NUM> is only removing a particular type of objects. In other scenarios, the manipulator <NUM> will interact and sort every object 106a, 106b, 106c which is on the conveyor belt <NUM>.

In some embodiments, 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 embodiments, 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 <NUM>. A fraction can be a standard or homogenous composition of material, such as aluminium, but alternatively a fraction can be category of waste defined by a customer or user.

In some embodiments, 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 embodiment, 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 embodiments, 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 <NUM>. 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 106a, 106b, 106c can be preprocessed 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 106a, 106b, 106c can be sorted with another robot or mechanical device. The objects 106a, 106b, 106c can be optionally pre-sorted before being placed on the conveyor belt <NUM>. For example, ferrous material can be removed from the unsorted waste by passing a magnet in proximity to the conveyor belt <NUM>. Large objects can be broken down into pieces of material which are of a suitable size and weight to be gripped by the manipulator <NUM>.

The manipulator <NUM> is configured to move within the working volume. The manipulator <NUM> comprises one or more mechanisms for moving the manipulator <NUM> in one or more axes. The mechanisms can be servos, pneumatic actuators or any other suitable means for moving the manipulator <NUM>. The manipulator <NUM> comprises one or more servos for moving the manipulator <NUM> in one or more axes. In some embodiments, the manipulator <NUM> is moveable along a plurality of axes. In some embodiments, the manipulator <NUM> is moveable along three axes which are substantially at right angles to each other. In this way, the manipulator <NUM> is movable in an X-axis which is parallel with the longitudinal axis of the conveyor belt <NUM> ("beltwise"). Additionally, the manipulator <NUM> is movable across the conveyor belt <NUM> in a Y-axis which is perpendicular to the longitudinal axis of the conveyor belt <NUM> ("widthwise"). The manipulator <NUM> is movable in a Z-axis which is in a direction normal to the working area <NUM> and the conveyor belt <NUM> ("heightwise"). Optionally, the manipulator <NUM> can rotate about one or more axes. In some embodiments a gripper assembly <NUM> coupled to the manipulator <NUM> can rotate about a W-axis. The gripper assembly <NUM> is discussed in further detail below.

The directions of movement of the manipulator <NUM> within the working space along the X-axis, Y-axis and the Z-axis are shown by the two headed arrows with dotted lines. The manipulator <NUM> is moved with respect to the conveyor belt <NUM> by an X-axis servo <NUM>, a Y-axis servo <NUM> and a Z-axis servo <NUM> respectively along the X-axis, the Y-axis and the Z-axis. The servos <NUM>, <NUM>, <NUM> are connected to the controller <NUM> and the controller <NUM> is configured to issue instructions for actuating one or more servos <NUM>, <NUM>, <NUM> to move the manipulator <NUM> within the working space <NUM>. The connections between the servos <NUM>, <NUM>, <NUM> and the controller <NUM> are represented by dotted lines. Each connection between the servo <NUM>, <NUM>, <NUM> and the controller <NUM> can comprises one or more data and / or power connections.

Since the directions of movement of the manipulator <NUM> are substantially perpendicular to each other, movement of the manipulator in one of the axes is independent of the other axes. This means that the manipulator <NUM> movement can be defined in a Cartesian coordinate frame of reference which makes processing movement instructions by the controller <NUM> simpler.

As mentioned previously, the manipulator <NUM> is mounted on a frame <NUM>. In some embodiments, the frame <NUM> can be a gantry frame <NUM>. In other embodiments, the frame <NUM> can be other structures suitable for supporting the manipulator <NUM> above the working area <NUM>. For example, the frame <NUM> can be a structure for suspending the manipulator <NUM> above the working area with rods and / or cables. Hereinafter, the frame <NUM> will be referred to a gantry frame <NUM> but can be applicable to other frames for supporting a manipulator <NUM>.

The gantry frame <NUM> comprises vertical struts <NUM> which engage with the floor or another substantially horizontal surface. In some embodiments, the vertical struts <NUM> 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 <NUM> to the floor in a non-standard installation. <FIG> shows the gantry frame <NUM> comprising four vertical struts <NUM> coupled together by horizontal beams <NUM>. In other embodiments, the horizontal beams <NUM> can be tilted lateral beams <NUM>. This may be required if the waste sorting gantry robot <NUM> is being installed in a small or unusual space. In other embodiments, there can be any suitable number of vertical struts <NUM>. The beams <NUM> and struts <NUM> are fixed together with welds, bolts or other suitable fasteners. Whilst the horizontal beams <NUM> are shown in <FIG> to be located above the conveyor belt <NUM>, one or more horizontal beams <NUM> can be positioned at different heights. For example, one or more horizontal beams <NUM> can be positioned underneath the conveyor belt. This can lower the centre of mass of the gantry frame <NUM> and make the entire waste sorting gantry robot <NUM> more stable if the vertical struts <NUM> are not secured to the floor.

The beams <NUM> and the struts <NUM> are load bearing and support the weight of the manipulator <NUM> and an object 106a, 106b, 106c that the manipulator <NUM> grasps. In some embodiments, the beams <NUM> and struts <NUM> are made from steel but other stiff, lightweight materials such as aluminium can be used. The vertical struts <NUM> can each comprise feet <NUM> comprising a plate through which bolts (not shown) can be threaded for securing the struts <NUM> to the floor. For the purposes of clarity, only one foot <NUM> is shown in <FIG>, but each strut <NUM> can comprise a foot <NUM>. In other embodiments, there are no feet <NUM> or fasteners for securing the gantry frame <NUM> 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.

The manipulator <NUM> comprises at least one movable horizontal beam <NUM> which is movably mounted on the gantry frame <NUM>. The moveable beam <NUM> can be mounted in a beam carriage (not shown). The moveable horizontal beam <NUM> is movably mounted on one or more of the other fixed horizontal beams <NUM> of the gantry frame <NUM>. The moveable horizontal beam <NUM> is movable in the X-axis such that the manipulator <NUM> moves in the X-axis when the movable horizontal beam moves in the X-axis. The moveable horizontal beam <NUM> is mounted to the fixed horizontal beams <NUM> via an X-axis servo mechanism <NUM>. In some embodiments, the servo <NUM> is coupled to the moveable horizontal beam <NUM> via a belt drive. In other embodiments, the servo is coupled to the moveable horizontal beam via a rack and pinion mechanism. In some embodiments, 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 <NUM>.

The X-axis servo <NUM> can be mounted on the moveable beam <NUM> or on the fixed horizontal beams <NUM>. It is preferable for the X-axis servo to be mounted on the fixed horizontal beams <NUM> such that the X-axis servo does not have to exert force moving its own weight.

A manipulator carriage <NUM> is movably mounted on the moveable horizontal beam <NUM>. The manipulator carriage <NUM> is moveable along the longitudinal axis of the movable horizontal beam <NUM>. In this way, the manipulator carriage <NUM> is movable in the Y-axis relative to the moveable beam <NUM>. In some embodiments, the manipulator carriage <NUM> comprises a Y-axis servo mechanism <NUM> for moving the manipulator carriage <NUM> along the Y-axis. In other embodiments, the Y-axis servo <NUM> is not mounted in the manipulator carriage <NUM> and manipulator carriage <NUM> moves with respect to the Y-axis servo. In some embodiments, the servo <NUM> is coupled to the moveable horizontal beam <NUM> via a belt drive. In other embodiments, the servo <NUM> is coupled to the moveable horizontal beam <NUM> via a rack and pinion mechanism. In some embodiments, other mechanisms can be used to actuate movement of the moveable horizontal beam along the Y-axis. For example, a hydraulic or pneumatic system can be used for moving the manipulator carriage <NUM>.

When the manipulator carriage <NUM> moves along the Y-axis, a gripper assembly <NUM> also moves in the Y-axis. The gripper assembly <NUM> is movably mounted to the manipulator carriage <NUM>. The gripper assembly <NUM> is movable in the Z-axis in order to move the manipulator <NUM> heightwise in the Z-axis direction.

In some embodiments, the gripper assembly <NUM> comprises a Z-axis servo mechanism <NUM> for moving the gripper assembly <NUM> along the Z-axis. In other embodiments, the Z-axis servo <NUM> is not mounted in the gripper assembly <NUM> but is mounted in the manipulator carriage <NUM>. In this way, the gripper assembly <NUM> moves with respect to the Z-axis servo <NUM>. In some embodiments, the servo <NUM> is coupled to the gripper assembly <NUM> via a belt drive. In other embodiments, the servo <NUM> is coupled to the gripper assembly <NUM> via a rack and pinion mechanism. In some embodiments, other mechanisms can be used to actuate movement of the moveable horizontal beam along the Z-axis. For example, a hydraulic or pneumatic system can be used for moving the gripper assembly <NUM>.

As mentioned, the manipulator <NUM> as shown in <FIG> comprises a gripper assembly <NUM>. The gripper assembly <NUM> can be a suction gripper (as shown in <FIG>) for gripping the objects using negative pressure with respect to atmospheric pressure. Hereinafter the gripper assembly <NUM> will be referred to as a suction gripper <NUM>. The suction gripper <NUM> can have a suction cup <NUM> (see <FIG>) which is substantially symmetric about the Z-axis. This means that the suction gripper <NUM> does not need to be rotated about the Z-axis to achieve an optimal orientation with respect to the objects 106a, 106b, 106c. This means that the gripper assembly rotation servo is not required with a suction gripper <NUM>. In the case with an asymmetrical suction gripper <NUM>, the gripper assembly <NUM> comprises a rotation servo to rotate the gripper assembly <NUM> about the W-axis as previously discussed above. Rotation of the suction gripper <NUM> about the W-axis is shown in <FIG>, but the servo for causing the rotation is not shown. The suction gripper <NUM> can have an elongate suction cup <NUM>. Additionally or alternatively, the suction gripper <NUM> can comprises a plurality of suction grippers. For example, the suction gripper <NUM> can comprise an asymmetrical suction gripper <NUM> comprising two suction tubes <NUM> each with a suction cup <NUM>.

In other embodiments, the suction gripper <NUM> of the manipulator <NUM> additionally comprise any suitable means for physically engaging and moving the objects 106a, 106b, 106c. Indeed, the manipulator <NUM> can additionally be one or more tools for grasping, securing, gripping, cutting or skewering objects. In further embodiments the manipulator <NUM> can additionally be a tool configured for interacting with and moving an object at distance such as an electromagnet or a nozzle for blowing compressed air.

As mentioned, the controller <NUM> is configured to send instructions to the servos <NUM>, <NUM>, <NUM> of the manipulator <NUM> to control and interact with objects 106a, 106b, 106c on the conveyor belt <NUM>. The controller <NUM> is connected to at least one sensor <NUM> for detecting the objects 106a, 106b, 106c on the conveyor belt <NUM>. The at least one sensor <NUM> is positioned in front of the manipulator <NUM> so that detected measurements of the objects 106a, 106b, 106c are sent to the controller <NUM> before the objects 106a, 106b, 106c enter the working area <NUM>. In some embodiments, the at least one sensor <NUM> 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, 3D imaging sensor, terahertz imaging system, radioactivity sensor and / or a laser. The at least one sensor <NUM> can be any sensor suitable for determining a parameter of the object 106a, 106b, 106c.

<FIG> shows that the at least one sensor <NUM> is positioned in one position. The at least one sensor <NUM> is mounted in a sensor housing <NUM> to protect the sensor <NUM>. In other embodiments, a plurality of sensors are positions along and around the conveyor belt <NUM> to receive parameter data of the objects 106a, 106b, 106c.

The controller <NUM> receives information from the at least one sensor <NUM> corresponding to one or more objects 106a, 106b, 106c on the conveyor belt <NUM>. The controller <NUM> determines instructions for moving the manipulator <NUM> based on the received information according to one or more criteria. Various information processing techniques can be adopted by the controller <NUM> for controlling the manipulator <NUM>. Such information processing techniques are described in <CIT>, <CIT>, <CIT>, <CIT> which are incorporated herein by reference.

Once the manipulator <NUM> has received instructions from the controller <NUM>, the manipulator <NUM> executes the commands and moves the suction gripper <NUM> to pick an object 106c from the conveyor belt <NUM>. The process of selecting and manipulating an object on the conveyor belt <NUM> is known as a "pick".

Once a pick has been completed, the manipulator <NUM> drops or throws the object 106c into a chute <NUM>. An object 106c dropped into the chute <NUM> is considered to be a successful pick. A successful pick is one where an object 106c was selected and moved to the chute <NUM> associated with the same fraction of waste as the object 106c.

The chute <NUM> comprises a chute opening <NUM> in the working area <NUM> for dropping picked objects 106c. The chute opening <NUM> of the chute <NUM> is adjacent to the conveyor belt <NUM> so that the manipulator <NUM> does not have to travel far when conveying a picked object 106c from the conveyor belt <NUM> to the chute opening <NUM>. By positioning the chute opening <NUM> of the chute adjacent to the conveyor belt <NUM>, the manipulator <NUM> can throw, drop, pull and / or push the object 106c into the chute <NUM>.

The chute <NUM> comprises walls <NUM> defining a conduit for guiding picked objects 106c into a fraction receptacle (not shown) for receiving a sorted fraction of waste. In some embodiments, a fraction receptacle is not required and the sorted fractions of waste are piled up beneath the chute <NUM>. <FIG> only shows one chute <NUM> associated with the manipulator <NUM>. In other embodiments, there can be a plurality of chutes <NUM> and associated openings <NUM> located around the conveyor belt <NUM>. Each opening <NUM> of the different chutes <NUM> is located within the working area <NUM> of the manipulator <NUM>. The walls <NUM> of the conduit can be any shape, size or orientation to guide picked objects 106c to the fraction receptacle. In some embodiments, the successfully picked objects 106c move under the force of gravity from the chute opening <NUM> of the chute <NUM> to the fraction receptacle. In other embodiments, the chute <NUM> may guide the successfully picked objects 106c to another conveyor belt (not shown) or other means for moving the successfully picked objects 106c to the fraction receptacle.

Turning to <FIG>, another embodiment will be discussed. <FIG> shows a schematic perspective view of a waste sorting gantry robot <NUM>. The conveyor belt <NUM> is positioned between the gantry frame <NUM>. For the purposes of clarity, no objects 106a, 106b, 106c have been shown on the conveyor belt <NUM>.

The gantry frame <NUM> as shown in <FIG> comprises a different configuration and construction from that shown in <FIG>. In particular, the gantry frame <NUM> comprises two cabinets <NUM>, <NUM>. The cabinet <NUM>, <NUM> comprise internal struts and horizontal beams similar to those discussed in reference to the embodiments shown in <FIG>. However the cabinet structures <NUM>, <NUM> comprise sheet material <NUM> to cover the struts and the horizontal beams providing the walls, top and bottoms of the cabinets <NUM>, <NUM>.

The cabinets <NUM>, <NUM> provide shielding for the delicate parts to the manipulator <NUM> such as the servos (not shown for clarity). This helps protect the manipulator from be damaged from stray waste objects. Furthermore the cabinet structures <NUM>, <NUM>, provide a barrier between the moving parts and the human operator. This means that the human operator cannot accidentally stray into the working area <NUM> of the waste sorting gantry robot. The gantry frame <NUM> comprises at least one enclosure <NUM>, <NUM>. The enclosure <NUM>, <NUM> surrounds at least a part of the gantry frame <NUM>. In some embodiments, there can be a plurality of enclosures <NUM>, <NUM>, each surrounding one or more parts of the waste sorting gantry robot <NUM>. The enclosure <NUM>, <NUM> can be a solid sheet material or can be perforated so that one or more internal parts of the waste sorting gantry robot <NUM> are visible. The enclosure <NUM>, <NUM> for example, surrounds the chute <NUM> on three sides. The enclosure <NUM>, <NUM> also surrounds at least a portion of the manipulator <NUM>. In other embodiments, the enclosure <NUM>, <NUM> can completely surround and enclose the waste sorting gantry robot <NUM>. In this case, the enclosure <NUM>, <NUM> comprises openings for the waste sorting objects 106a, 106b, 106c to be conveyed into the working area <NUM>.

<FIG> shows a suction gripper <NUM> which is in fluid communication with a pneumatic system <NUM>. The pneumatic system <NUM> comprises at least one hose <NUM> for connecting the suction gripper <NUM> to the pneumatic system <NUM>. In some embodiments, the hose is an air hose <NUM> for providing a source of air to the suction gripper <NUM>. In some embodiments, there is a single, unitary air hose connected to the suction gripper <NUM>. By providing only one air hose <NUM> to the suction gripper <NUM>, installation and maintenance of the waste sorting robot <NUM> is simplified. Furthermore, by only having one air hose and not requiring a long vacuum hose for the suction gripper <NUM>, there are less energy losses due to friction in the pneumatic system <NUM>. Operation of the suction gripper <NUM> using the single air hose <NUM> will be discussed in further detail below.

The air hose <NUM> is flexible and threaded along the movable horizontal beam <NUM> in to the cabinet <NUM>. In some embodiments, (not shown in <FIG>) the air hose <NUM> can be inserted within the hollow moveable beam <NUM>. The hose <NUM> is sufficiently flexible to move and flex so as to change shape as the manipulator <NUM> moves without impeding the movement of the manipulator <NUM>.

At least a portion of the pneumatic system <NUM> is housed in the cabinet <NUM> or the gantry frame <NUM>. The pneumatic system <NUM> can comprise an air compressor for generating a source of compressed air. Optionally, the pneumatic system <NUM> can also comprise an air storage tank (not shown) for compressed air. Furthermore, the pneumatic system <NUM> can also comprise one or more valves <NUM> for selectively providing air to the suction gripper <NUM>. In some embodiments, the air compressor generates an air source having a pressure of <NUM> Bar. In other embodiments, the air source has a pressure of <NUM> Bar to <NUM> Bar. In other embodiments, the air source can have any suitable pressure above atmospheric pressure.

The pneumatic system <NUM> is schematically shown as being located within the cabinet <NUM>. However, in other embodiments the pneumatic system <NUM> can be partially or wholly located remote from the waste sorting robot <NUM>. For example, there may be a plurality of waste sorting robots <NUM> 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 <NUM> via a plurality of air hoses <NUM>. Accordingly, the pneumatic system <NUM> may be located between waste sorting robots <NUM>.

<FIG> shows a schematic cross section of the waste sorting gantry robot <NUM>. Operation of the pneumatic system <NUM> is controlled by the controller <NUM>. This means that the controller <NUM> can selectively operate e.g. the air compressor or the valve <NUM> of the pneumatic system <NUM> to deliver a supply of air to the suction gripper <NUM>.

The pneumatic system <NUM> comprises at least one pressure sensor <NUM> configured to measure the pressure in the suction gripper <NUM>. The pressure sensor <NUM> is in fluid communication with the suction cup <NUM> (as shown in <FIG>). In this way, the pressure at the pressure sensor <NUM> is the same or similar to the pressure in the suction cup <NUM>. The pressure sensor <NUM> is mounted to the suction gripper <NUM> so that the pressure sensor <NUM> is proximal to the suction cup <NUM>. The pressure sensor <NUM> is connected to the controller <NUM>. The connection between the pressure sensor <NUM> and the controller <NUM> is represented by the dotted line therebetween. The pressure sensor <NUM> can be coupled to the controller <NUM> with a wired or a wireless connection. The wireless connection can transmit the pressure signal over radio frequency from the pressure sensor <NUM> to the controller <NUM>. The pressure sensor <NUM> determines the current operating fluid pressure in the suction gripper <NUM> at the suction cup <NUM> and sends a measurement signal to the controller <NUM>. The signal is an output voltage which varies in dependence of the fluid pressure in the suction cup <NUM>. In other embodiments, the signal is a current output which varies in dependence of the fluid pressure in the suction cup <NUM>.

In some embodiments, optionally the at least one pressure sensor <NUM> is a plurality of pressure sensors <NUM> for measuring the pressure at different points in suction gripper <NUM>. A plurality of pressure sensors <NUM> can indicate the pressure differential across different parts of the suction gripper <NUM>. Identifying the location of a pressure differential is advantageous because it can indicate the location of a blockage in the suction gripper <NUM>.

In some embodiments the pressure sensor <NUM> is mounted on an integrated circuit (not shown) for pre-processing the measurement signal. This means that the integrated circuit coupled to the pressure sensor sends a data packet to the controller <NUM> comprising information relating to the pressure at the suction cup <NUM>.

In some embodiments, the pressure sensor <NUM> can be mounted anywhere on the suction gripper <NUM>. As long as the pressure sensor <NUM> is in fluid communication with the suction cup <NUM> of the suction gripper <NUM>, the pressure sensor <NUM> can measure the pressure at the suction cup <NUM>.

The pressure sensor <NUM> can be a piezoelectric pressure sensor, electrostatic pressure sensor, piezoresistive pressure sensor, resonant pressure sensor, a pressure transducer, a Wheatstone bridge pressure transducer, a differential pressure transducer, a diaphragm pressure sensor, an inductive pressure sensor, a reluctive pressure sensor, a board mounted pressure sensor, or an optical pressure sensor. In other embodiments, the pressure sensor <NUM> can be any suitable means for measuring the pressure in the suction gripper <NUM>.

In some embodiments, the pressure sensor <NUM> comprises a plastic housing. A plastic housing may be preferable because this reduces the weight of the pressure sensor <NUM> and increases the maximum payload of the suction gripper <NUM>. In some embodiments, the pressure sensor <NUM> is a board mounted pressure sensor and is mounted on the inside of the suction pipe <NUM>.

An embodiment of the suction gripper <NUM> will now be discussed in reference to <FIG> shows a cross sectional side view of the suction gripper <NUM> in operation. The suction gripper <NUM> comprises a suction cup <NUM> having a side wall <NUM> and a suction mouth <NUM>. In some embodiments, the suction cup <NUM> has a top wall (not shown) and the distance between opposite side walls <NUM> narrows towards the top of the suction cup <NUM>. The suction mouth <NUM> of the suction cup <NUM> is arranged to engage with an object to be sorted 106c. The suction cup <NUM> comprises a hollow construction and a generally circular cross-section (across the Z-axis). In other embodiments, the suction cup <NUM> is elongate across the Z-axis and has a rectangular or oval cross-sectional shape.

As mentioned in some embodiments, the suction cup <NUM> can be elongate and / or asymmetrical about one or more axes. In this case, the suction gripper <NUM> may comprise a rotation servo (not shown) to rotate the suction gripper <NUM> about the W-axis as previously discussed in reference to <FIG>.

In some embodiments, the side wall <NUM> of the suction cup <NUM> comprises a ribbed or concertinaed wall portion <NUM>. The ribbed wall portion <NUM> creates a resiliently flexible portion in the suction cup <NUM> such that the suction cup <NUM> preferentially compresses in the Z-axis. In this way, when the suction cup <NUM> descends in the direction of the Z-axis and engages the object 106c, the ribbed wall portion <NUM> help absorbs force of the impact which protects the manipulator <NUM>. Furthermore, the concertina shape of the side wall <NUM> allows the suction cup <NUM> to conform to the shape of the object to be picked 106a, 106b.

The suction cup <NUM> is made from a resiliently deformable material such as silicon, rubber or other similar material. This means that the suction cup <NUM> can deform when the suction cup abuts an irregular shape. Accordingly, the suction cup <NUM> can make a better seal between the lip <NUM> of the side wall <NUM> and the object 106c to be picked.

The suction cup <NUM> comprises an air hole <NUM> in fluid communication with a first air inlet <NUM> of a suction tube <NUM> for evacuating air from the space within the suction cup <NUM>. The air hole <NUM> comprises a diameter which is the same size as or similar to the diameter of the suction tube <NUM>. This means that the air can flow easier between the suction cup <NUM> to the suction tube <NUM>. In this way, the diameter of the sidewall <NUM> is the same as the diameter of the suction tube <NUM>. In other embodiments, the diameters of the air hole <NUM> and the suction tube <NUM> may be different and the bore of the suction tube narrows or widens. Optionally, there is a seal between the air hole <NUM> and the suction tube <NUM> so that no air flow is enters between the join of the suction cup <NUM> at the air hole <NUM> and the suction tube <NUM>.

The suction tube <NUM> comprises an elongate side wall <NUM>. The suction tube <NUM> comprises the first air inlet <NUM> at one end and an air outlet <NUM> at another end. The elongate side wall <NUM> comprises a longitudinal axis A-A which is substantially parallel with the Z-axis. Both the first air inlet <NUM> and the air outlet <NUM> are aligned with the longitudinal axis A-A of the suction tube <NUM>. This means that the suction air flow path from the first air inlet <NUM> to the air outlet <NUM> is a straight line. This means that there are no curves or blockages which impede the air flow in the suction tube <NUM>.

The air hole <NUM> is sealed to the first air inlet <NUM>. The suction cup <NUM> can be glued to the suction tube <NUM> between the air hole <NUM> and the first air inlet <NUM>. In other embodiments, the suction cup <NUM> and the suction tube <NUM> are integral and there is no join between the air hole <NUM> and the first air inlet <NUM>.

The suction tube <NUM> is cylindrical and comprises a circular cross-sectional shape (across the Z-axis). In other embodiments, the suction tube is not a cylinder and comprises an oval, square, rectangular, or irregular cross-sectional shape. The suction tube <NUM> as shown in <FIG> comprises a uniform diameter, but the suction tube <NUM> can vary in width along the longitudinal length of the suction tube <NUM>. In some embodiments, the suction tube <NUM> is between <NUM> to <NUM> long.

The suction air flow through the suction gripper <NUM> enters from the mouth <NUM> suction cup <NUM>, through the air hole <NUM>, along the suction tube <NUM>, and exits the suction tube <NUM> at the air outlet <NUM>. Arrows represent air flow into, through and out of the suction gripper <NUM> as shown in <FIG>.

The negative pressure generated for the suction air flow will now be described. A negative pressure is a pressure relative to and less than atmospheric pressure. The suction air flow for the suction gripper <NUM> is generated near the suction cup <NUM> of the suction gripper <NUM>, which avoids the need for a vacuum hose.

The suction tube <NUM> comprises a second air inlet <NUM> which is in fluid communication with the air hose <NUM>. Accordingly, the second air inlet <NUM> introduces an air source of compressed air into the suction tube <NUM> between the first air inlet <NUM> and the air outlet <NUM>. In this way the air source of compressed air exits the second air inlet <NUM> and the source of compressed air is introduced into the suction air flow path. The second air inlet <NUM> is in the side wall <NUM> of the suction tube <NUM> and so the air source is initially introduced perpendicular to the longitudinal axis A-A of the suction tube <NUM>. However, the second air inlet <NUM> also directs the air flow into the suction tube <NUM> towards the air outlet <NUM>. In some embodiments, the second air inlet <NUM> comprises a curved nozzle (not shown) for changing the direction of the air source towards the air outlet <NUM>. In some embodiments, the second air inlet <NUM> can be any suitable nozzle for introducing an air flow into the suction tube <NUM>.

As shown in <FIG>, the second air inlet <NUM> comprises an annular nozzle <NUM> which is coaxial with the suction tube <NUM>. The annular nozzle <NUM> is in fluid communication with the air hose <NUM>. The air hose <NUM> is coupled to a nozzle housing <NUM>. The nozzle housing <NUM> surrounds the annular nozzle <NUM> and seals against the suction tube <NUM>. This means that air flowing from the air hose <NUM> to the annular nozzle <NUM> does not escape outside the suction tube <NUM>. The nozzle outlet of the annular nozzle <NUM> directs the air flow into the suction tube <NUM> and in the direction of the air outlet <NUM>.

The pressure sensor <NUM> is mounted on the nozzle housing <NUM>. The pressure sensor <NUM> is coupled to the suction tube <NUM> by connection conduit <NUM>. In other embodiments the pressure sensor <NUM> can be mounted elsewhere on the suction gripper <NUM>. For example, the pressure sensor can be mounted on the suction cup <NUM>. In some embodiments, the pressure sensor <NUM> can be mounted within the nozzle housing <NUM>. In this way, the nozzle housing <NUM> protects the pressure sensor <NUM> from being damaged.

The nozzle housing <NUM> is connected to the suction tube <NUM> either side of the annular nozzle <NUM>. This increases the mechanical strength of the suction tube <NUM> and the annular nozzle <NUM>. In some embodiments, the suction tube <NUM> comprises an upper part <NUM> and a lower part <NUM> which are coupled together by the nozzle housing <NUM>. In this way, the annular nozzle <NUM> is sandwiched between the upper part <NUM> and the lower part <NUM>. The nozzle outlet is flush with the interior wall <NUM> of the suction tube <NUM>. In this way, the annular nozzle <NUM> does not obscure any part of the suction tube <NUM>.

The air flow exits the annular nozzle <NUM> and creates an annular air flow towards the air outlet <NUM>. Advantageously, the annular nozzle <NUM> creates an initial air flow with a greater surface area when compared to a point-like nozzle. Accordingly the air flow from the annular nozzle <NUM> entrains air from the suction tube <NUM> into the air flow moving towards the air outlet <NUM>. This creates a larger air flow in the suction tube <NUM>.

Furthermore, the annular nozzle <NUM> does not block the centre of the cross-section area of the suction tube <NUM>. This means that the air flow is not blocked by the nozzle itself. This means that the suction tube is less likely to become blocked by foreign objects which ingress into the suction tube <NUM>. Indeed, using a rod or a bottle cleaner is easier to clear blockages.

In some embodiments, the housing <NUM> comprises a chamber <NUM> for receiving the compressed air from the air hose <NUM>. The chamber <NUM> may be in fluid communication with the annular nozzle <NUM> that intersects with the internal bore <NUM> of the suction tube <NUM>. In this way, the annular nozzle <NUM> is not a separate element but defined by the internal walls of the housing <NUM> and the suction tube <NUM>. The first and second parts <NUM>, <NUM> are screw mounted in the housing <NUM> and spaced apart from each other to define the annular nozzle <NUM>. The rate of flow of the compressed air into the suction tube <NUM> can be varied by changing the relative width of the annular nozzle <NUM>. The width of the annular nozzle <NUM> can be varied by changing the separation of the first and second parts <NUM>, <NUM> from each other. In particular, the first and / or the second parts can be screw mounted into the housing <NUM>. By screwing the first and / or the second parts <NUM>, <NUM> in and out of the housing <NUM>, the relative distance between the first and second parts <NUM>, <NUM> can be changed. Accordingly, this can change the rate at which the compressed air enters the suction tube <NUM> and varies the suction force.

The second air inlet <NUM> introduces a fast, high pressure source of air into the suction tube <NUM>. The second air inlet <NUM> is narrower than the suction tube <NUM> and so the air flow emerging from the second air inlet <NUM> expands into the wider volume of the suction tube <NUM>. As the air source from the second air inlet <NUM> expands in the suction tube <NUM>, it reduces in velocity and mixes with the air in the suction tube <NUM>. The momentum of the air emerging from the second air inlet <NUM> mixing with the air in the suction tube <NUM> causes the mixed air to move towards the air outlet <NUM>. As the air in the suction tube <NUM> moves towards the air outlet <NUM>, a negative pressure is created in the suction tube between the second air inlet <NUM> and the first inlet <NUM>. A negative pressure is also created in the suction cup <NUM> since the suction cup <NUM> is in fluid communication with the suction tube <NUM>.

Depending on the quality of the seal between the suction cup <NUM> and the object 106c, some air will enter the suction cup <NUM> due to the negative pressure in the suction cup <NUM>. Once the negative pressure is low enough, the suction gripper <NUM> will generate sufficient force to pick up and convey the object 106c. In some embodiments, the object 106c is released by stopping the flow of air into the suction tube <NUM> from the second air inlet <NUM>. This increases the air pressure in the suction cup <NUM> and the object 106c will fall away from suction cup <NUM> due to the force of gravity.

Advantageously, the arrangement shown in <FIG> is a simple construction and generates the negative pressure at the suction cup <NUM>. This means that a vacuum hose which is coupled to a vacuum pump is not required. Indeed, a smaller, lighter flexible air hose is only required to generate suction at the suction cup <NUM>.

Turning to <FIG>, an arrangement for unblocking the suction gripper <NUM> will now be discussed. <FIG> shows a cross-sectional side view of a modified suction gripper <NUM>.

The suction gripper <NUM> is predominantly the same as the suction gripper <NUM> as described in the embodiments with reference to the other Figures. Indeed, the suction cup <NUM>, the suction tube <NUM> and the annular nozzle <NUM> are the same as shown in <FIG>.

The suction gripper <NUM> comprises a suction component <NUM> which is the same as the suction gripper <NUM> arrangement as shown in <FIG>. Accordingly, the suction component <NUM> will not be described in any further detail. The suction gripper <NUM> also comprises a blow component <NUM>. The suction cup <NUM>, the blow component <NUM> and the suction component <NUM> are indicated by the dotted lines perpendicular to the axis B-B. The blow component <NUM> is the essentially the same as the suction component <NUM> but reversed in orientation to generate a positive air pressure rather than a negative air pressure. In some embodiments, the suction component <NUM> is optimized for maximum gripping / suction force. In other embodiments, the blow component <NUM> is additionally and / or alternatively be optimized for maximum ability to remove blockages. The arrangement as shown in <FIG> comprises identical components, however in alternative embodiments, the suction component <NUM> and the blow components are not identical.

As shown in <FIG>, the pressure sensor <NUM> is mounted on the nozzle housing <NUM> of the suction component <NUM>. However, in other embodiments, additionally or alternatively a pressure sensor (not shown) is mounted in the nozzle housing <NUM> of the blow component <NUM>. A pressure sensor mounted on the blow component <NUM> can provide further information to the controller <NUM> as to whether there are blockages in the suction gripper <NUM>.

The blow component <NUM> comprises the same features as the suction component <NUM>. The blow component <NUM> comprises a blow tube <NUM>. The blow tube <NUM> comprises an elongate side wall which is substantially cylindrical. The blow tube <NUM> comprises the first air inlet <NUM> at one end and an air outlet <NUM> at another end. The air outlet <NUM> is coupled to and in fluid communication with the air outlet <NUM> of the suction tube <NUM>. The elongate side wall comprises a longitudinal axis B-B which is substantially parallel with the Z-axis. The longitudinal axis B-B of the blow tube <NUM> is the same as the longitudinal axis B-B of the suction tube <NUM>.

Both the first air inlet <NUM> and the air outlet <NUM> of the blow tube <NUM> are aligned with the longitudinal axis B-B of the blow tube <NUM>. This means that the air flow path from the first air inlet <NUM> to the air outlet <NUM> is a straight line. This means that there are no curves which impede the air flow in the blow tube <NUM>.

Similarly to the suction tube <NUM>, the blow tube <NUM> comprises a second air inlet <NUM> which is in fluid communication with the air hose <NUM>. Accordingly, the second air inlet <NUM> of the blow tube <NUM> introduces an air source into the blow tube <NUM> between the first air inlet <NUM> and the air outlet <NUM>. The second air inlet <NUM> is an annular nozzle similar to that described in <FIG>. In other embodiments, the second air inlet <NUM> of the blow tube <NUM> can be any type of nozzle for introducing an air flow into the blow tube <NUM>.

The air hose <NUM> is coupled to both of the second air inlets <NUM>, <NUM> of the suction tube <NUM> and the blow tube <NUM> respectively. A three-way valve <NUM> is coupled to the air hose <NUM> for selectively providing an air flow to either the suction tube <NUM> or the blow tube <NUM>. In some embodiments the three-way valve <NUM> can be replaced with two separate valves (not shown). This means that the suction gripper <NUM> can selectively be operated in a first mode whereby a negative pressure is provided at the suction cup <NUM> or a second mode whereby a positive pressure is provided at the suction cup <NUM>. The three-way valve <NUM> comprises a solenoid for actuating the valve <NUM>. The solenoid is controllable from instructions received from the controller <NUM>. Alternatively the three-way valve could be actuated with a pneumatic control signal.

When the suction gripper <NUM> is in the first mode or the "suction mode", the suction gripper <NUM> operates in the same way as the embodiments previously discussed in reference to <FIG>. The air flow travels from the suction tube <NUM> to the blow tube <NUM>. In this way, the air flow exits the suction gripper at the first air inlet <NUM> of the blow tube <NUM>. Accordingly, the first air inlet <NUM> of the blow tube <NUM> serves a dual purpose and is an air outlet in the first mode.

In the second mode, or the "blow mode", the air flow through the suction gripper <NUM> is reversed. Indeed, <FIG> shows the blow component <NUM> in operation and the air flow flowing from the blow component <NUM> to the suction cup <NUM>. Air is drawn in from the first air inlet <NUM> and flows through the blow tube <NUM> to the suction tube <NUM> and exits at the air hole <NUM> of the suction cup <NUM>. The positive air pressure exerts a force on a blocking object <NUM> causing a blockage in the suction tube <NUM>. The force of the positive air flow can push the blocking object <NUM> out from the suction cup.

The suction gripper <NUM> has been discussed being used in combination with a waste sorting gantry robot <NUM>. However, the suction gripper <NUM> can be used with any sort of wasting sorting robot <NUM>. For example, the suction gripper <NUM> can be used with delta robots, robot arms or any other manipulator <NUM> controlled by a controller <NUM>.

Another embodiment will now be described in reference to <FIG> shows a schematic cross sectional side view of the waste sorting robot. The gripper assembly <NUM> is mounted to the Z-axis servo <NUM> via a slidable coupling <NUM>. In some embodiments, the gripper assembly <NUM> is mounted to the Z-axis servo via a plurality of slidable couplings <NUM>. Indeed, other embodiments, there can be any number of slidable couplings <NUM> between the gripper assembly <NUM> and the Z-axis servo <NUM>. For the purposes of clarity only one slidable coupling <NUM> is shown in <FIG>.

The slidable coupling comprises a first part <NUM> coupled to the gripper assembly <NUM> and a second part <NUM> which is coupled to the Z-axis servo <NUM>. The first part <NUM> is fastened to the suction tube <NUM> of the gripper assembly <NUM>. In other embodiments, the first part <NUM> is fastened to any other component of the gripper assembly <NUM>. The second part <NUM> is fastened to the rack <NUM> associated with a rack and pinion mechanism of the Z-axis servo <NUM>. In some embodiments, the first and second parts <NUM>, <NUM> are bolted, glued, welded, screwed respectively to the gripper assembly <NUM> and the rack <NUM> of the Z-axis servo <NUM> mechanism.

The first and second parts <NUM>, <NUM> of the slidable coupling <NUM> are arranged to slide with respect to each other. The relative movement of the first part <NUM> and the second part <NUM> is in a direction which is normal to the plane of the conveyor belt <NUM> and / or the working area <NUM>. In other words, the first part <NUM> and the second part <NUM> move relative to each other in the Z-axis. The first and second parts <NUM>, <NUM> are elongate and each have longitudinal axis which are aligned along a longitudinal axis B-B (shown in <FIG>). In some embodiments, the first and second parts <NUM>, <NUM> are parallel with the Z-axis. In some other embodiments, the first part <NUM> and the second part <NUM> are not parallel with the Z-axis, but tilted with respect to the Z-axis. In this case when the first and second parts <NUM>, <NUM> slide relative to each other, a component of the movement is in the Z-axis.

In some embodiments, the first part <NUM> is a rod and the second part <NUM> is a hollow sleeve <NUM> for receiving the rod <NUM>. In some embodiments the hollow sleeve <NUM> and the rod <NUM> are aluminium extrusions, although the hollow sleeve <NUM> and the rod <NUM> can be made from any other suitable material such as steel. The slidable coupling <NUM> can be any suitable mechanism to let the gripper assembly <NUM> to move with respect to the Z-axis servo <NUM>. For example, the first part <NUM> can be a hollow sleeve and the second part <NUM> can be a rod. In other embodiments, both the first and second parts <NUM>, <NUM> can both be elongate elements, for example, rods which are slidably coupled to each other. The rods (not shown) can be arranged side by side and slide against their respective exterior surfaces. In other embodiments, the slidable coupling <NUM> can be a "lazy tongs" scissor mechanism.

In some embodiments, the first part <NUM> is slidably coupled to the second part <NUM> by virtue of a plurality of wheels (not shown). In some embodiments, there are a plurality of sets of wheels arranged to engage the exterior surface <NUM> of the rod <NUM> at a plurality of locations along the rod <NUM>. Each set of wheels comprises wheels to keep the rod <NUM> aligned along the longitudinal axis of the hollow sleeve <NUM>. The wheels can protrude slightly through the hollow sleeve <NUM>. However, in other embodiments the wheels can be mounted within the hollow sleeve <NUM> between the rod <NUM> and the interior surface <NUM> of the hollow sleeve <NUM>. The bearings of the wheels are coupled to the hollow sleeve <NUM> to fix the rotation of axis of the wheels with respect to the hollow sleeve <NUM>. In other embodiments, the bearings of the wheels are coupled to the rod <NUM>.

In operation, the Z-axis servo <NUM> lowers the gripper assembly <NUM> towards an object 106a, 106b, to be picked. As the gripper assembly <NUM> engages the surface of the object 106a, the first part <NUM> and the second part <NUM> of the slidable coupling <NUM> move with respect to each other. At the point at which an object 106a, 106b, 106c is detected by the controller <NUM>, the controller <NUM> sends a signal to the Z-axis servo <NUM> to stop moving towards the conveyor belt <NUM> and start moving up and away from the conveyor belt <NUM>. Due to the inertia of the suction gripper <NUM> and the whole Z-axis servo mechanism <NUM> moving downwards, the suction gripper <NUM> will take a period of time before the suction gripper <NUM> actually starts to move upwards. This means that the suction gripper <NUM> moves downwards for a period of time before the Z-axis servo <NUM> moves the suction gripper <NUM> upwards. As the suction gripper <NUM> moves downwards, the slidable coupling <NUM> contracts and the suction gripper <NUM> is not forced into the object 106a, 106b to be picked or the conveyor belt <NUM>. In this way, the slidable coupling <NUM> is a shock absorber that protects the manipulator <NUM> from collision with conveyor belt <NUM> or objects 106a, 106b. This prevents damage to the manipulator <NUM> and / or the conveyor belt <NUM>. Furthermore, since the slidable coupling <NUM> slides, the objects 106a, 106b to be picked are not crushed and this increases the likelihood that the suction gripper <NUM> makes a successful pick.

In some embodiments, the conveyor belt <NUM> is made from material that does not form a good seal with the suction cup <NUM>. The conveyor belt <NUM> may be made from an air permeable material or a porous material. In some embodiments, the surface of the conveyor belt <NUM> has a rough surface which prevents the suction cup <NUM> from making a good seal against the conveyor belt <NUM>. In this way if the suction cup <NUM> engages with the conveyor belt <NUM>, the suction gripper <NUM> is not damaged or the conveyor belt <NUM> is not damaged from the manipulator <NUM> lifting the suction gripper <NUM> upwards. Additionally or alternatively, the suction gripper <NUM> is configured to lower to a position just above (e.g. a few millimetres above) the conveyor belt <NUM> so that the suction cup <NUM> does not physically engage the conveyor belt <NUM> when the slidable coupling <NUM> is fully extended.

In some embodiments, the slidable coupling <NUM> comprises a rubber protective sleeve <NUM> which covers the slidable coupling <NUM>. In this way the rubber protective sleeve <NUM> prevents dust and other debris damaging the slidable coupling mechanism <NUM>. Furthermore, the rubber protective sleeve helps absorb collision energy.

The rod <NUM> of the first part comprises a first seal <NUM> and optionally a second seal <NUM>. The first and second seals <NUM>, <NUM> engage both the exterior surface <NUM> of the rod <NUM> and an interior surface <NUM> of the hollow sleeve <NUM>. The seals <NUM>, <NUM> are fixed to the exterior surface <NUM> of the rod <NUM> and the seals <NUM>, <NUM> slide along the interior surface <NUM> of the hollow sleeve <NUM>. Alternatively the seals <NUM>, <NUM> are fixed to the interior surface <NUM> of the hollow sleeve <NUM> and slide with respect to the exterior surface <NUM> of the rod <NUM>. Accordingly, the seals <NUM>, <NUM> make a seal between the rod <NUM> and the hollow sleeve <NUM>. The seals <NUM>, <NUM> restrict the airflow between the rod <NUM> and the hollow sleeve <NUM> to act as a shock absorber. In this way, rod <NUM> and the hollow sleeve <NUM> form a pneumatic shock absorber. The air in the hollow sleeve <NUM> is trapped by the seals <NUM>, <NUM> and creates a piston.

The hollow sleeve comprises a valve <NUM> for selectively controlling the airflow out and in of the hollow sleeve <NUM>. In some embodiments, the valve <NUM> is a ball valve <NUM> which allows air to freely escape from the hollow sleeve <NUM> when the rod <NUM> is compressed into the hollow sleeve <NUM>. When the rod <NUM> is pulled out of the hollow sleeve <NUM>, the ball valve <NUM> limits the rate that air can re-enter the hollow sleeve <NUM>. In alternative embodiments, the valve can be a rubber flap (not shown) which rests over an air hole connected to the interior of the hollow sleeve <NUM>. The rubber flap flexes away from the hollow sleeve <NUM> when air exits the hollow sleeve <NUM>. When the rod <NUM> extends from the hollow sleeve <NUM>, the rubber flap covers the air hole and slowly lets air enter the hollow sleeve <NUM>.

Operation of the waste sorting robot <NUM> will now be described in reference to <FIG>. <FIG> and <FIG> show a schematic flow diagram of a method of controlling the waste sorting robot <NUM>. <FIG> is a schematic graph of the pressure of the suction gripper <NUM> over time during operation of the suction gripper <NUM>.

Turning to <FIG>, one embodiment will now be discussed. Optionally, in step <NUM> the manipulator <NUM> of the waste sorting robot <NUM> is in a "start" position. The start position can be any position of the manipulator <NUM> before the pick operation is carried out. For example, after an object 106c has been picked and disposed down a chute <NUM>, and there is no immediate next object to pick, the waste sorting robot <NUM> can either stop, or do something else.

In some embodiments, if the waste sorting robot <NUM> stops after a pick, this means the manipulator <NUM> is left standing near a chute <NUM>. When the next object 106a, 106b comes, the manipulator <NUM> moves from the start position which is the position the manipulator <NUM> is in after the preceding pick was completed.

If the controller <NUM> determines that there is another pick to carry out immediately after the preceding pick, then the start position will be the finishing position of the preceding pick. In this way, the start position it not a fixed position with respect to the gantry frame <NUM>, but will vary depending on the decisions that the controller <NUM> makes.

The controller <NUM> can decide after a previous pick where to move the manipulator <NUM>. If controller <NUM> has no next pick, then the controller <NUM> decides to move to the manipulator <NUM> to a position to wait for the next object. In this way, the position where the manipulator <NUM> waits for the next object will be the start position for the next pick. If the controller <NUM> decides to move the manipulator <NUM> to a waiting position, the start position can be optionally a predetermined position of the manipulator <NUM> in which the manipulator <NUM> is moved to before a manipulator <NUM> movement is carried out. In some embodiments, the start position is a predetermined position in reference to the frame <NUM> and / or the working area <NUM>. In some embodiments, the start position is a predetermined "home" position in the middle of the conveyor belt <NUM> and / or the working area <NUM> where the waste objects to be sorted enter the working area <NUM>. In this way, the start position is a ready position which is the best position to wait for the next object 106a, 106b in order to reduce the travel time of the manipulator <NUM>.

In some embodiments, the controller <NUM> may know the location of the manipulator <NUM> with sub-millimetre accuracy. Information relating to the position of the manipulator <NUM> is sent to the controller <NUM> from one or more encoders from the rear end of the servos <NUM>, <NUM>, <NUM>. In some other embodiments, the location of the manipulator is determined additionally or alternatively to an encoder in the servo <NUM>, <NUM>, <NUM>. For example, the location of the manipulator <NUM> is determined from one or more other sensors (not shown) such as a camera or a proximity sensor mounted on the manipulator <NUM> or on the conveyor belt <NUM>. In some embodiments, the controller <NUM> may be connected to one or more sensors for determining the position of the manipulator <NUM>. Optionally the position sensor may be an encoder in a servo, a camera, a proximity sensor, an optical sensor, an infrared sensor, an ultrasound sensor, a laser distance sensor, a hall sensor, or any other suitable sensor for determining the position of the manipulator <NUM> and / or the suction gripper <NUM>. The at least one position sensor may be mounted on the manipulator <NUM> or the suction gripper <NUM> alternatively, the at least one position sensor may be mounted remotely from the manipulator <NUM> or the suction gripper <NUM>. In some embodiments there is at least one position sensor configured to generate a position signal in dependence of the position of the manipulator <NUM> and / or the suction gripper <NUM>. In some embodiments the at least one position sensor is configured to send the position signal in dependence of the position of the manipulator <NUM> and / or the suction gripper <NUM> to the controller <NUM>.

In some embodiments, the waste sorting robot <NUM> optionally comprises at least one synchronising switch (not shown) which is located at a known reference location on the gantry frame <NUM>. Whenever the axis drives past that switch, the controller <NUM> can verify whether the servo <NUM>, <NUM>, <NUM> drive's position matches with the known physical location of the synchronising switch. This means that if some gear, clutch or belt between the servo <NUM>, <NUM>, <NUM> and the suction gripper <NUM> slips, the position derived from the position of the servo motor no longer in synchronisation with the actual location of the suction gripper <NUM>. If the controller identifies a mismatch, the controller <NUM> can stop waste gantry sorting robot <NUM> from operating. In some embodiments, the synchronising switches are located around the start position as mentioned above.

If the pneumatic system <NUM> is not in operation prior to step <NUM>, then the pressure in the suction cup <NUM> as detected by the pressure sensor <NUM> will be atmospheric pressure (Patmos). This is show as the horizontal line <NUM> in <FIG>.

After step <NUM>, the controller <NUM> initiates a pick of an object 106a, 106b, 106c. In this case, the controller <NUM> operates the suction assembly <NUM> so that the suction assembly operates in a suction mode as shown in step <NUM>. In particular, the controller <NUM> sends a control signal to the valve <NUM> to select the valve <NUM> in a suction mode. In the suction mode, compressed air is introduced into the second air inlet <NUM> of the suction component <NUM>. Accordingly the suction gripper assembly <NUM> creates a negative pressure in the suction cup <NUM>. This means that the suction gripper <NUM> is ready for a pick.

In step <NUM>, as the air flow in the suction tube <NUM> creates the suction, the pressure in the suction cup <NUM> will drop slightly from normal atmospheric pressure Patmos to an operating pressure Pnormal as shown as horizontal line <NUM> in <FIG>. The drop in pressure will only be slight because there is no obstruction in the suction cup <NUM> and therefore replacement air will flow into the suction cup <NUM> constantly.

When the controller <NUM> initiates the pick operation, the manipulator <NUM> is in a start position. If the particular start position of the manipulator <NUM> and the suction gripper <NUM> for the current pick is above the conveyor belt <NUM>, this means that the manipulator <NUM> must descend to the conveyor belt <NUM> so that the suction cup <NUM> is able to physically engage with the object to be sorted 106a, 106b, 106c. In normal operation, the manipulator <NUM> moves the suction gripper <NUM> at a height above the conveyor belt <NUM> not to collide with any objects 106a, 106b, 106c. When the waste gantry sorting robot <NUM> begins a pick, it moves the suction gripper <NUM> above the object to be picked. This motion is advantageously carried out in a way so as to not hit any other objects on the way. In some embodiments, during the motion or after stopping the manipulator <NUM> above the object, the suction is turned on as shown in step <NUM>. The controller <NUM> sends a movement instruction to the servos <NUM>, <NUM>, <NUM> to move the manipulator <NUM>. In particular the Z-axis servo <NUM> is actuated to move the suction gripper <NUM> in a downwards direction as shown in step <NUM>. This operation will still have the same pressure as in step <NUM> as shown by line <NUM> in <FIG>.

Whilst the suction gripper <NUM> is descending, the controller <NUM> optionally performs a pressure status check of the suction gripper <NUM> as shown in step <NUM>. During the pressure status check <NUM>, the controller <NUM> receives pressure information from the pressure sensor <NUM>. The pressure sensor <NUM> obtains information relating to the pressure status in the suction cup <NUM>. The pressure sensor <NUM> can measure one or more parameters of the pressure in the suction cup <NUM>. In one embodiment, the pressure sensor <NUM> measures the magnitude of the pressure in the suction cup <NUM>. That is, the pressure sensor <NUM> detects whether the pressure is a positive or negative pressure relative to atmospheric pressure and the size of the relative pressure. The pressure sensor <NUM> may measure the absolute pressure in the suction cup <NUM> or may determine a relative pressure of the suction cup <NUM> with respect to atmospheric pressure. A relative pressure of the suction cup <NUM> is compared for example the pressure measurement of the suction cup <NUM> before the pneumatic system <NUM> is in operation or e.g. atmospheric pressure. In some embodiments, the pressure sensor <NUM> determines the rate of change of the pressure in the suction cup <NUM>.

Determining the rate of change of the pressure in the suction cup <NUM> may be useful because a sudden rate of change can indicate that the status of the suction gripper has changed. For example is the suction cup <NUM> has suddenly physically engaged an object, the pressure will drop rapidly to a negative pressure (e.g. <NUM> mBar below atmospheric pressure).

If the controller <NUM> determines in step <NUM> that the pressure information indicates that the suction gripper <NUM> has not engaged an object to be sorted, the controller <NUM> continues to instruct the manipulator <NUM> to descend to the conveyor belt <NUM>. This is represented by an arrow between step <NUM> and step <NUM> labelled PSensor > PSuction. In some embodiments the controller <NUM> compares a pressure measurement received from the pressure sensor <NUM> with a threshold suction pressure (PSuction). The threshold suction pressure is a predetermined pressure of a partial vacuum required in the suction cup <NUM> which will generate sufficient suction force to life objects to be sorted 106a, 106b, 106c on the conveyor belt <NUM>.

In some embodiments, the threshold suction pressure PSuction may be a pressure which is not large enough to generate a suction force. In this way, the threshold suction pressure PSuction is a pressure that distinguishes between the suction cup <NUM> not being engaged with an object and the suction cup <NUM> engaging with an object. Once the controller <NUM> determines that the pressure in the suction cup <NUM> is below the threshold suction pressure PSuction , the controller <NUM> decrease the pressure in the suction cup <NUM> to generate a suction force and a lifting force on the object.

In some embodiments, the threshold suction pressure is <NUM> mBar below atmospheric pressure. The threshold suction pressure can be any suitable negative pressure required to generate a suction force to lift an object. In some embodiments, the lifting force can be between 10N to 50N. As the air flow in the suction tube <NUM> creates the suction, the pressure in the suction cup <NUM> will drop from normal atmospheric pressure to the operating pressure Pnormal, but the pressure not will not go below the threshold suction pressure indicating a partial vacuum has been formed between the suction cup <NUM> and the object 106a, 106b, 106c. The drop in pressure from the operating pressure Pnormal <NUM> to a negative pressure during a picking operation is shown as a rapidly decreasing pressure line <NUM> in <FIG>.

In some embodiments, the controller <NUM> may be continuously receiving a pressure signal from the pressure sensor <NUM>. In other embodiments, the controller <NUM> receives the pressure signal periodically, for example at a frequency of <NUM> (every <NUM>). The frequency of the controller <NUM> polling the pressure sensor <NUM> can be increased if the controller <NUM> needs to determine changes in the pressure more rapidly.

In some embodiments, the controller <NUM> uses the pressure signal from the pressure sensor <NUM> to control the airflow in the second air inlet <NUM> and the suction force in the suction gripper <NUM>. This means that the controller <NUM> varies the suction force generated by the suction gripper <NUM> in dependence of the pressure signal. In this way, the controller <NUM> uses the pressure signal in a control feedback loop for varying the suction force of the suction gripper <NUM>. For example, the controller <NUM> can determine from the pressure signal that the pressure in the suction cup <NUM> is increasing, accordingly the controller <NUM> can determine that the grip of the picked object is becoming less secure. In order to increase the likelihood of a successful pick, the controller <NUM> can increase the suction force of the suction gripper <NUM> to make the engagement of the suction gripper <NUM> with the picked object more secure. In this way, less compressed air may be used if the seal is good while still being able to grip if the seal is bad. Using less compressed air is preferable because it requires a significant amount of electricity to generate the compressed air.

The controller <NUM> determines in step <NUM> that the pressure in the suction cup <NUM> is below a threshold suction pressure PSuction. Accordingly, the controller <NUM> determines that the pressure has dropped in the suction cup <NUM> is because the suction gripper <NUM> has engaged the surface of an object 106a, 106b, 106c. This is represented by the intersection <NUM> in <FIG>.

In step <NUM>, the controller <NUM> determines that the pressure in the suction cup <NUM> is maintained below the threshold suction pressure PSuction and the object has been successfully gripped by the suction gripper <NUM>. This is shown in <FIG> by the horizontal line <NUM> below the threshold suction pressure PSuction. In this way, the controller <NUM> determines that the status of the suction gripper <NUM> is gripping an object.

In an alternative embodiment, the controller <NUM> determines that the suction gripper <NUM> has physically engaged an object 106a, 106b, 106c based on the rate of change of the pressure in the suction cup <NUM>. In this way, the controller <NUM> can determine faster that the suction gripper <NUM> has successfully gripped an object. This is because the rate of change of the pressure in the suction cup <NUM> will be a function of how well the suction cup <NUM> seals against the surface of the object 106a, 106b, 106c. Accordingly, if the suction cup <NUM> has a good seal the pressure will drop quicker in the suction cup <NUM>. This means that the controller <NUM> can determine that the suction gripper <NUM> is gripping the object before the magnitude of the pressure in the suction cup <NUM> has actually fallen below the threshold suction pressure PSuction. In other embodiments, signal processing such as filtering can be used on the pressure signal by the controller <NUM> to determine a status of the suction gripper <NUM>.

The controller <NUM> determines the rate of change of the pressure in the suction cup <NUM> based on the pressure information. If the rate of change of the pressure is greater than a predetermined rate of pressure change, then the controller <NUM> determines that the suction gripper <NUM> is gripping an object. Once the controller <NUM> has determined that the suction gripper <NUM> is successfully gripping the object, the controller <NUM> sends a movement command to the manipulator <NUM>. Specifically the controller <NUM> sends a movement command to the Z-axis servo <NUM> to reverse the movement of the suction gripper <NUM> towards the conveyor belt <NUM> such that the suction gripper <NUM> moves away from the conveyor belt <NUM>.

Since the controller <NUM> and the Z-axis servo <NUM> have a latency between the controller <NUM> issuing an instruction and the Z-axis servo <NUM> performing the movement due to signalling lag as well as mechanical limitations that require the Z-axis servo <NUM> servo to use a limited amount acceleration and/or jerk when changing direction, the controller <NUM> can use the determination that the rate of change of the pressure in the suction cup <NUM> to change the direction of the suction gripper <NUM>.

This is because when the Z-axis servo receives the instruction to move the suction gripper <NUM> away from the conveyor belt <NUM>, enough time has passed for the pressure in the suction cup <NUM> to be below the threshold suction pressure PSuction. This means that the manipulator <NUM> action of descending, gripping and ascending can be sped up.

Another embodiment of operation of the manipulator <NUM> and the suction gripper <NUM> will now be discussed in reference to <FIG> shows a method of operating the suction gripper <NUM> in order to unblock the suction tube <NUM>.

Steps <NUM>, and <NUM> are the same in <FIG> as in <FIG>. However, in some instances the suction gripper <NUM> may not be operating correctly when the controller <NUM> controls the pneumatic system <NUM> and supplies air to the suction tube <NUM>. For example, it is possible that the suction gripper <NUM> is blocked by debris before the suction gripper <NUM> performs a pick.

Similar to step <NUM> in <FIG>, the controller <NUM> receives pressure information from the pressure sensor <NUM>. Accordingly, when the controller <NUM> receives pressure information from the pressure sensor <NUM>, the controller <NUM> determines that the pressure of the suction cup <NUM> is not operating at a normal operating pressure Pnormal when the suction gripper <NUM> is in the start position as shown in check step <NUM>. For example, the determined pressure is below the normal operating pressure Pnormal. This indicates that the suction tube <NUM> is fully or partially blocked. If the controller <NUM> determines that the suction gripper <NUM> is operating normally, then the controller <NUM> returns to step <NUM>.

In some embodiments, the controller <NUM> performs the check step <NUM> on the suction gripper <NUM> when the suction gripper <NUM> is known not to be gripping an object 106a, 106b, 106c. For example, the controller <NUM> can perform the check step <NUM> of the pressure of the suction cup <NUM> before the picking operation is carried out. The controller <NUM> can carry out the suction gripper check step <NUM> in the start position.

In other embodiments, the controller <NUM> carries out a suction gripper check step <NUM> after other trigger events. For example, if the controller <NUM> determines that a pick has been unsuccessful or the suction gripper <NUM> has malfunctioned. In some embodiments, the controller <NUM> may perform the suction gripper check <NUM> after the suction gripper <NUM> has failed to successfully pick an object a predetermined number of times (e.g. after five unsuccessful picks). In other embodiments, the check step <NUM> is performed at any time during operation of the suction gripper <NUM>. In yet other embodiments, the check step <NUM> is carried out whenever there are no objects to pick. In this way, the controller <NUM> can use time when the manipulator <NUM> is not carrying out a pick to ensure the suction gripper <NUM> is not blocked. As shown in <FIG> and <FIG>, the check step <NUM> is performed before the manipulator <NUM> descends in step <NUM>.

In some embodiments, the controller <NUM> performs the suction gripper check step <NUM> when the suction gripper <NUM> is remote from the conveyor belt. This means that the controller <NUM> can use the pressure information to distinguish between a successful gripping operation as shown in <FIG> and a blockage.

Accordingly, the controller <NUM> determines that the suction gripper <NUM> is blocked based on the pressure information as shown in step <NUM>. Optionally as mentioned above, the controller can additionally use other information such as the position, movement and status of the manipulator to determine that the suction gripper <NUM> is blocked.

Once the controller <NUM> has determined that the suction gripper <NUM> is blocked, the controller <NUM> can take remedial action to unblock the suction gripper <NUM>. In this case, the controller <NUM> operates the suction gripper <NUM> so that the suction gripper <NUM> operates in a blow mode as shown in step <NUM>. In particular, the controller <NUM> sends a control signal to the valve <NUM> to select the valve <NUM> in a blow mode.

In the blow mode, compressed air is introduced into the second air inlet <NUM> of the blow component <NUM>. Accordingly the suction gripper assembly <NUM> creates a positive pressure in the suction cup <NUM>. This means that the airflow is reverse through the suction gripper <NUM> and pushes the blocking object <NUM> out of the suction cup <NUM> as shown in step <NUM>. The pressure of the suction cup <NUM> is shown in <FIG> by the line <NUM> indicating the rapidly increasing pressure and the short burst of positive, above atmospheric pressure.

Optionally, the controller <NUM> can position the manipulator <NUM> so that the blocking object <NUM> is fired clear of the conveyor belt <NUM>. Once the blockage has cleared, the controller <NUM> can instruct the manipulator <NUM> to the start position as shown in <FIG>. Operating the suction gripper <NUM> at the normal operating pressure, Pnormal after Pblow is shown by line <NUM> in <FIG>.

A further embodiment will now be discussed with respect to <FIG>. Steps of the methods of operations as discussed with respect to the embodiments shown in <FIG> and <FIG> are incorporated into <FIG>. The steps which are the same to the previously discussed steps have the same reference number and will not be described again.

As mentioned, the operation of gripping an object is the same as shown in <FIG>. However once the suction gripper <NUM> has physically engaged the object 106a, 106b, 106c, it is possible that the grip fails. For example, the seal between the suction cup <NUM> and the object is not good enough. This may be caused by, for example, the object having a rough surface, an increased object porosity, an edge of the suction cup <NUM> overlapping the edge of the object 106a, 106b, 106c, or the seal between the suction cup <NUM> and the object 106a, 106b, 106c is not good enough. Another possible reason for a failing grip is that the object is too heavy. The grip may further fail because the centre of gravity of the object is too far from the suction gripper <NUM>. Indeed, the relative position of the suction gripper <NUM> with respect to the object 106a, 106b, 106c may not be optimal. In these cases, the suction force generated by the suction gripper <NUM> is not sufficient and the object falls away from the suction gripper <NUM> as the manipulator <NUM> moves away from the working area <NUM>.

In this case, it is advantageous that the controller <NUM> knows that the object is no longer being gripped by the suction gripper <NUM>. Accordingly the controller <NUM> can determine that the grip has failed based on pressure information received from the pressure sensor <NUM>. In this way, the grip step <NUM> comprises a grip check step <NUM>, similar to step <NUM>. The grip check step <NUM> continues once the suction gripper <NUM> has physically engaged the object.

If the controller <NUM> determines that the pressure rises rapidly during the grip check step <NUM>, the controller <NUM> determines that the grip has failed as shown in step <NUM>. The controller <NUM> determines from the pressure information that the pressure in the suction cup <NUM> is above the threshold suction pressure PSuction and therefore no object is being gripped by the suction gripper <NUM>. The rapid rise in the pressure from the operating suction pressure Pop_suck to the normal operating pressure Pnormal at the suction cup <NUM> is shown by the dotted rising line <NUM> in <FIG>. Additionally or alternatively, the controller <NUM> waits a period of time, e.g. <NUM> before determining that the suction gripper <NUM> has failed to grip an object. If the controller <NUM> determines that there has been a grip failure in step <NUM>, the controller <NUM> may optionally send instructions to move the manipulator <NUM> to pick an object in the vicinity of the current location of the manipulator <NUM>.

Alternatively, once the controller <NUM> determines that the grip has failed, the controller <NUM> can instruct the manipulator <NUM> to start a new picking operation if a suitable object 106a, 106b, 106c is available and the start position is wherever the manipulator <NUM> is currently located. This means consecutive picks start at the position where the previous pick attempt ended. Alternatively, if no new object is available, the controller <NUM> instructs the manipulator <NUM> to go to the home position to wait for an object 106a, 106b to become available when carried into the working area <NUM> by the conveyor belt <NUM>.

If the controller <NUM> determines that the status of the suction gripper <NUM> is that an object 106a, 106b, 106c is being held, the controller <NUM> instructs the manipulator <NUM> to convey the object 106a, 106b, 106c to the chute <NUM> as shown in step <NUM>. Once the manipulator <NUM> is conveying the object, the object 106a, 106b, 106c has been lifted off the conveyor belt <NUM> and is moved relative to the conveyor belt <NUM> at a height above the conveyor belt <NUM>.

However, during a conveying operation step <NUM>, it is possible that the suction gripper <NUM> does not maintain a successful grip on the object. This may be for similar reasons that the grip failed in step <NUM>.

Accordingly, the controller <NUM> may perform a conveying grip check step as shown in step <NUM>. This step in <NUM> is the same as to the grip check <NUM> previously discussed in reference to <FIG>. If the pressure of the suction cup <NUM> rapidly rises during the conveying step, the controller <NUM> determines that an object has slipped off the suction gripper <NUM> as shown in step <NUM>. The rapid rise in the pressure from the operating suction pressure Pop_suck to the normal operating pressure Pnormal at the suction cup <NUM> is shown by the dotted rising line <NUM> in <FIG>. Once the controller <NUM> determines that an object has slipped off the suction gripper <NUM>, the controller <NUM> instructs the manipulator <NUM> to the start position in step <NUM> for another picking operation as previously discussed.

If the conveying operation in step <NUM> is successful, the manipulator <NUM> moves the picked object 106c over the chute <NUM> or proximal to the chute <NUM>. At this point the controller <NUM> can release the picked object 106c into the chute <NUM>. In some embodiments, the controller <NUM> drops the picked object 106c by stopping the air supply to the suction tube <NUM>. In this way, the suction force is removed from the suction gripper <NUM> and the picked object 106c will fall under the force of gravity into the chute <NUM>.

Alternatively or additionally, the controller <NUM> can reverse the airflow through the suction tube <NUM> so that the picked object <NUM> is blown off the suction gripper <NUM>. To blow the picked object 106c from the suction gripper <NUM>, the controller <NUM> operates the suction gripper <NUM> in the blow mode as shown in step <NUM>. The blow operation is shown in step <NUM> and has been previously discussed in reference to <FIG>. Optionally, the controller <NUM> can implement the blow or release operation in step <NUM> whilst the manipulator is moving towards the chute <NUM>. Accordingly, the picked object 106c is "thrown" to the chute <NUM>. This can be advantageous because the manipulator does not have to travel as far, increasing the number of picks that can be made by the waste sorting robot <NUM>.

In some embodiments, the controller <NUM> instructs a blow operation <NUM> to be carried out after each pick whether it is successful or not. In this way, the positive airflow through the suction tube <NUM> is constantly cleaning the debris from the suction tube <NUM>. This ensures that a buildup of debris in the suction tube <NUM> does not occur.

Another embodiment will now be discussed in reference to <FIG> shows a schematic flow diagram of a method of operation of the suction gripper <NUM>. The method is the same has <FIG> except that some of the method steps are in a different order. In particular, the suction step <NUM> does not immediately start once the manipulator <NUM> is in the start position. Indeed, the suction gripper <NUM> descends towards the conveyor belt <NUM> with the source of compressed air turned off. In this way, the suction gripper <NUM> is not creating a suction force whilst the suction gripper <NUM> descends.

The controller <NUM> determines that the suction gripper <NUM> has physically engaged the object when the slidable coupling <NUM> starts to slide. The controller <NUM> receives a signal from at least one sensor configured to detect relative motion between the first and second parts <NUM>, <NUM> of the slidable coupling <NUM>. The sensor detects that the suction gripper <NUM> has moved between a first position and a second position relative to the manipulator <NUM>. The at least one sensor can be a microswitch, an optical sensor to detect relative movement, an ultrasonic distance sensor, an infrared sensor, a stress/strain gauge a pressure sensor coupled to the ball valve <NUM> to detect air being urged out of the hollow sleeve <NUM> when the slidable coupling <NUM> compresses or any other suitable sensor for detecting relative movement between the first and second part <NUM>, <NUM>. The controller <NUM> controls the Z-axis servo <NUM> to move the suction gripper <NUM> downwards until the controller receives a signal from the at least one sensor that the slidable coupling <NUM> has started to slide as shown in step <NUM>. In response to the signal, the controller <NUM> starts the suction in step <NUM>. In this way, the compressed air supply is only turned on when the suction cup <NUM> is physically engaging the object. The controller <NUM> before or after the suction step <NUM> also stops the downward movement of the suction gripper <NUM> as shown in step <NUM>. The rest of the steps of the method are the same as previously discussed.

In other embodiments, the suction gripper arrangements as described with respect to the <FIG> and the operation of the suction grippers discussed in reference to <FIG> and <FIG> can also be used with other types of object manipulation robots. For example, the suction gripper <NUM> 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.

In another embodiment two or more embodiments are combined. Features of one embodiment can be combined with features of other embodiments.

Claim 1:
A waste sorting robot (<NUM>) comprising:
a manipulator (<NUM>) comprising a suction gripper (<NUM>) for interacting with one or more waste objects (106a, 106b, 106c) to be sorted within a working area (<NUM>), wherein the manipulator (<NUM>) is moveable within the working area (<NUM>) and wherein the suction gripper (<NUM>) is moveable relative to the manipulator (<NUM>) between a first position being a start position and a second position in which the suction gripper engages a waste object;
a controller (<NUM>) configured to send control instructions to the manipulator (<NUM>); and
at least one sensor configured to detect the suction gripper (<NUM>) moving between the first and second positions, whereby the controller is configured to determine the suction gripper (<NUM>) has engaged a waste object;
characterized in that the controller (<NUM>) is configured to actuate the suction gripper (<NUM>) in dependence on a signal detecting the suction gripper (<NUM>) has moved between the first and second positions so that suction in the suction gripper (<NUM>) is turned on in the second position.