SE2250230A1

SE2250230A1 - An outdoor robotic work tool comprising an environmental detection system adapted to detect obstacles

Info

Publication number: SE2250230A1
Application number: SE2250230A
Authority: SE
Inventors: Christopher Walfridson; Stefan Bergström
Original assignee: Husqvarna Ab
Priority date: 2022-02-21
Filing date: 2022-02-21
Publication date: 2023-08-22
Also published as: DE102023103665A1

Abstract

ABSTRACT The present disclosure relates to an outdoor robotic work tool (100) adapted for a forward travelling direction (D) and comprising a control unit (120), an environmental detection system (110) that comprises at least one detector transceiver (170) adapted to transmit signals (180a) and to receive reflected signals (180b) that have been reflected by an object (182). The control unit (120) is adapted to determine if an object (182) has been detected by the detector transceiver (170), and if an object (182) has been determined to have been detected, the control unit (120) is adapted to determine a detected extension (183, 185) of the object (182) by means of the received reﬂected signals (180b). The control unit (120) is adapted to determine an estimated continued extension (184) of the object (182).

Description

TECHNICAL FIELD The present disclosure relates to outdoor robotic work tool comprising an environmental detection system with a detector transceiver arrangement. The outdoor robotic work tool can for example be constituted by a robotic lawn mower.

BACKGROUND Automated or robotic power tools such as robotic lawn mowers are becoming increasingly more popular. ln a typical deployment a work area, such as a garden, the work area is enclosed by a boundary wire with the purpose of keeping the robotic lawn mower inside the work area. An electric control signal may be transmitted through the boundary wire thereby generating an (electro-) magnetic field emanating from the boundary wire. The robotic working tool is typically arranged with one or more sensors adapted to sense the control signal.

The robotic lawn mower can then cut grass on a user's lawn automatically and can be charged automatically without intervention of the user, and no longer needs to be manually managed after being set once. The robotic lawn mower needs to have a function of detecting obstacles to avoid colliding with the obstacle before encountering the obstacle, and to have a function of recognizing that a collision has occurred. ln the latter case, a collision sensor can be disposed on the body of the robotic lawn mower, and when the robotic lawn mower collides with an obstacle, the body moves in such a way that the collision sensor generates a collision signal. ln the former case, different kinds of environment detection sensors are use such as ultrasonic sensors as disclosed in EP3508048 and radar sensors as disclosed in SE540794.

There is, however, a need to improve the coverage, reliably and efficiency of such environment detection sensors such that all obstacles are detected in time such that a collision can be avoided by changing direction of the robotic lawn mower, stopping the robotic lawn mower and/or turning the robotic lawn mower away from the obstacle.

This should work for different types of obstacles at different positions relative the robotic lawn mower.

SUMMARY The object of the present disclosure is to provide a robotic work tool with environment detection system that is adapted to handle different types of obstacles at different positions relative the robotic lawn mower.

This object is achieved by means of an outdoor robotic work tool adapted for a forward travelling direction and comprising a control unit, an environmental detection system that comprises at least one detector transceiver adapted to transmit signals and to receive reflected signals that have been reflected by an object. The control unit is adapted to determine if an object has been detected by the detector transceiver. lf an object has been determined to have been detected, the control unit is adapted to determine a detected extension of the object by means of the received reflected signals. The control unit is further adapted to determine an estimated continued extension of the object.

When an object has been detected, and its continued extension has been estimated, this opens for a plurality of actions to handle the object, for example avoiding the object as will be discussed later.

According to some aspects, the control unit is adapted to determine an estimated continued extension of the object by extrapolation of the detected extension.

This means that it is assumed that the object continues in the same manner as the detected extension. The more detected extension that are acquired, the more accurate the continued extension of the object can be estimated, According to some aspects, the control unit is adapted to determine an estimated continued extension of the object when the detected extension has reached a certain threshold. This means that it is determined when the detected extension of the object is considered sufficient to determine the estimated continued extension.

According to some aspects, the control unit is adapted to determine an estimated continued extension of the object by comparing a first detected extension of the object with a second detected extension of the object, adding to the first detected extension. The second detected extension has been determined after the first detected extension has been determined.

This means that the detections reveal more and more of the object, and also reveal how the object extends.

According to some aspects, the control unit is adapted to control the outdoor robotic work tool to slow down. Slowing down will provide more time for performing other actions, and/or alleviating a possible collision.

According to some aspects, the control unit is adapted to control the outdoor robotic work tool to turn away from the estimated continued extension of the object. The robotic work tool is then enabled to perform an evasive maneuver to avoid collision with the object based on the estimation.

According to some aspects, the control unit is adapted to control the outdoor robotic work tool to position itself in front of the estimated continued extension of the object such that the detector transceiver is enabled to further detect the object, such that the control unit is enabled to verify the estimated continued extension of the object.

According to some aspects, the control unit is adapted to control the outdoor robotic work tool to stop and to then perform a turning movement such that the detector transceiver is enabled to scan the object by means of multiple detections, such that the control unit is enabled to verify the estimated continued extension of the object.

This action can be performed as a complement to the previously described action, and will provide further data regarding the extension of the object.

The present disclosure also relates to methods that are associated with above advantages.

BRIEF DESCRIPTION OF THE DRAWINGS The present disclosure will now be described more in detail with reference to the appended drawings, where: Figure 1A shows a schematic perspective view of a |awn mower; Figure 1B Figure 2 Figure 3 Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 shows a schematic top view of the |awn mower; shows a schematic top view of a |awn mower and an object; shows a schematic top view of a |awn mower and an object at a first time; shows a schematic top view of a |awn mower and an object after the first time according to a first example; shows a schematic top view of a |awn mower and an object after the first time according to a second example; shows the second example according to Figure 5 in a yet further time. schematically illustrates a control unit; shows a computer program product; shows a flowchart for methods according to the present disclosure; and shows a schematic top view of a |awn mower and an object after the first time according to a third example.

DETAILED DESCRIPTION Aspects of the present disclosure will now be described more fully hereinafter with reference to the accompanying drawings. The different devices, systems, computer programs and methods disclosed herein can, however, be realized in many different forms and should not be construed as being limited to the aspects set forth herein. Like numbers in the drawings refer to like elements throughout.

The terminology used herein is for describing aspects of the disclosure only and is not intended to limit the invention. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. ln the following, a typical robotic lawn mower will be described, but of course the present disclosure may depart from this description. lt should be noted that even though the description given herein will be focused on robotic lawn mowers, the teachings herein may also be applied to any type of outdoor robotic work tool, such as for example robotic ball collectors, robotic mine sweepers and robotic farming equipment.

Figure 1A shows a perspective view of a robotic lawn mower 100 and Figure 1 B shows a schematic overview of the robotic lawn mower 100. The robotic lawn mower 100 is adapted for a forward travelling direction D, has a body 140 and a plurality of wheels 130; in this example the roboticlawnmower100 has four wheels 130, two front wheels and two rear wheels. The robotic lawn mower100 comprises at least one electric motor 150, where at least some of the wheels 130 are drivably connected to at least one electric motor 150. lt should be noted that even if the description herein is focused on electric motors, combustion engines may alternatively be used in combination with an electric motor arrangement. The robotic lawn mower 100 may be a multi-chassis type or a mono-chassis type. A multi-chassis type comprises more than one body parts that are movable with respect to one another. A mono-chassis type comprises only one main body part.

The robotic lawn mower 100 comprises charging skids 156 for receiving a charging current from a charging station, and possibly also for transferring information by means of electrical communication between the charging station and the robotic lawn mower 100. ln this example embodiment, the robotic Iawnmower 100 is of a mono-chassis type, having a main body part 140. The main body part 140 substantially houses all components of the robotic Iawnmower 100.

The robotic Iawnmower 100 also comprises a grass cutting device 160, such as a rotating blade 160 driven by a cutter motor 165. The grass cutting device being an example of a work tool 160 for a robotic working tool 100. The robotic lawnmower 100 also has at least one rechargeable electric power source such as a battery 155 for providing power to the electric motor arrangement 150 and/or the cutter motor 165. The battery 155 is arranged to be charged by means of received charging current from the charging station 200, received through charging skids 156 or other suitable charging connectors. lnductive charging without galvanic contact, only by means of electric contact, is also conceivable; the charging skids 156 and the contact plates 210 are generally constituted by a charging reception arrangement 156 and a charging transmission arrangement 210. The battery is generally constituted by a rechargeable electric power source 155 that comprises one or more batteries that can be separately arranged or be arranged in an integrated manner to form a combined battery.

According to some aspects, the robotic Iawnmower 100 also comprises means 157 for detecting a boundary wire and/or a navigation sensor arrangement 158 in a previously known manner.

The robotic Iawnmower 100 comprises a control unit 120 and an environmental detection system 110 that comprises at least one detector transceiver 170 adapted to transmit signals 180a and to receive reflected signals 180b that have been reflected by an object 182. With reference also to Figure 2 and Figure 3, the control unit 120 is adapted to determine if an object 182 has been detected by the detector transceiver 170, and if an object 182 has been determined to have been detected, the control unit 120 is adapted to determine a detected extension 183 of the object 182 by means of the received reflected signals 180b.

The detector transceivers 170 can be of any suitable kind, such as for example ultrasonic, radar or Lidar transceivers. Combinations of these and other kinds of detector transceivers are of course conceivable. ln Figure 1B two forvvard-looking detector transceivers 170 are shown but there can be any suitable number of detector transceivers with any suitable positons and coverages.

As shown in Figure 2, the closer an angle that the transmitted signals 180a present to the surface of a target 182 comes to 90°, the higher portion of the energy in the reflected signal 180b will be received by the detector transceiver 170. This is very schematically illustrated in the Figure by a number of reflected signals 180b (only a few indicated for reasons of clarity) emanating from where the transmitted signals 180a reach the object 182. lt should be noted that for example in the case of the detector transceiver 170 being a radar transceiver, a transmitter antenna will according to some aspects transmit most energy in the forward travelling direction D and lesser energy when departing from the forward travelling direction D, due to the antenna beam pattern configuration.

This results in that the determined detected extension 183 of the object 182 will be only a part of the object 182 at a first time as shown in Figure 3. The continuing extension 187 is at this moment unknown to the environmental detection system 110 and the control unit 120.

Therefore, according to the present disclosure, the control unit 120 is adapted to determine an estimated continued extension 184 of the object 182. This estimation can be performed at any time, when a part of the object 182 has been detected. When an object has been detected, and its continued extension 184 has been estimated, this opens for a plurality of actions to handle the object 182, for example avoiding the object as will be discussed later.

According to some aspects, the control unit 120 is adapted to determine an estimated continued extension 184 of the object 182 when the detected extension 183, 185 has reached a certain threshold. This means that a part 183, 185 of the object 182 has been detected, where this part 183, 185 has been determined to be sufficient to determine the estimated continued extension 184 of the object 182. As an example, a length L of the part 183, 185 of the object 182 that has been detected exceeds a threshold length LT such that L > LT.

According to some aspects, as illustrated in Figure 4, the control unit 120 is adapted to determine an estimated continued extension 184 of the object by comparing a first detected extension 183 of the object 182 with a second detected extension 185 of the object 182, adding to the first detected extension 183, where the second detected extension 185 has been determined after the first detected extension 183 has been determined. This means that the detections revea| more and more of the object 182, and also revea| how the object 182 extends. Here, the detected extension 183, 185 comprises a first detected extension 183 and a second detected extension 185, but there may any number of such detected extensions. There should be at least one detected extension.

According to some aspects, the control unit 120 is adapted to determine an estimated continued extension 184 of the object 182 by extrapolation of the detected extension 183. This means that it is assumed that the object 182 continues in the same manner as the detected extension 183, 185. The more detected extension 183, 185 that are acquired, the more accurate the continued extension 184 of the object 182 can be estimated, and the closer the robotic lawnmower 100 will come to the object 182.

Accordingly, as the robotic lawnmower 100 moves the forward travelling direction D it will approach the object 182, and more and more of the object 182 will be known and a prediction of the continued extension 184 of the object will become more and more reliable. At the same time it will be more and more important to determine the extension of the object 182 in front ofthe robotic lawnmower 100, enabling the robotic lawnmower 100 to take one or more suitable actions.

Having determined the estimated continued extension 184 of the object 182, the robotic lawnmower 100 is enabled to take one or more suitable actions, according to some aspects the control unit 120 is adapted to control the robotic lawn mower 100 to slow down. This may be a single action, where the robotic lawn mower 100 then is allowed to collide with the object 182 at the reduced speed. This may also be an action that is combined with other actions, such as -for example -the ones described in the following. Slowing down will provide more time for performing other actions, and/or alleviating a possible collision.

According to some aspects, the control unit 120 is adapted to determine if a present route 131 will intersect the object 182, and if that is the case, the control unit 120 is adapted to control the robotic lawn mower 100 to turn 132 away from the estimated continued extension 184 of the object 182, as illustrated in Figure 4. The robotic lawnmower100 is then enabled to perform an evasive maneuver to avoid collision with the object 182 based on the estimation 184. lt is of course possible that the estimated continued extension 184 of the object 182 is misleading and does not coincide with the actual continued extension of the object 182. ln order to be able to determine a more accurate estimated continued extension 184 of the object 182, a number of further actions are possible, and some of these will be described in the following.

According to some aspects, as illustrated in Figure 5, the control unit 120 is adapted to control the robotic lawn mower 100 to position itself in front of the estimated continued extension 184 of the object 182 such that the detector transceiver 170 is enabled to further detect the object 182, such that the control unit 120 is enabled to verify the estimated continued extension 184 of the object 182.

This means that the robotic lawn mower 100 follows a path 130 that first turns away from the estimated continued extension 184, and then turns towards the estimated continued extension 184 such that, according to some aspects, the forward travelling direction D is directed towards the estimated continued extension 184.

According to some aspects, as indicated with dashed lines in Figure 5 and Figure 6, the control unit 120 is adapted to control the robotic lawn mower 100 to stop and to then perform a turning movement 100a, 100b such that the detector transceiver 170 is enabled to scan the object 182 by means of multiple detections, such that the control unit 120 is enabled to verify the estimated continued extension 184 of the object 182. This action can be performed as a complement to the previously described action, and will provide further data regarding the extension of the object 182.

Verifying, or checking, the estimated continued extension 184 of the object 182 can thus be performed when an object 182 has been determined to exist, and when the estimated continued extension 184 has been determined and found to be of interest, for example to block the movement of the robotic lawn mower 100 in its present forward trave||ing direction D. As mentioned above, an evasive maneuver can be taken with or without such a verification. lf the estimated continued extension 184 is verified to be correct and correspond to the object 182, the robotic lawn mower 100 continues working using this information about the object 182. Correspondingiy, ifthe estimated continued extension 184 is not correct and does not correspond to the object 182, as i||ustrated in Figure 6, the robotic lawn mower 100 continues working using this information about the object 182. ln Figure 6, the object 182 has been determined to make a bend 133 that does not correspond to the estimated continued extension 184. lf the robotic lawn mower 100 continued work leads to a similar situation as described above with reference to Figure 3, the procedure or procedures described will be repeated. lt is to be appreciated that some of the actions above can be combined, and all actions can be combined with reduced speed. Other actions are of course also conceivable, such as repeating the verification of the estimated continued extension 184 of the object 182 as described with reference to Figure 5 and Figure 6 until the object 182 is satisfactorily defined. The data of the object 182 may be saved in a local memory of the control unit or at a remote memory, for example at a remote server or a charge station. ln Figure 7 it is schematically i||ustrated, in terms of a number of functional units, the components of the control unit 120 according to embodiments of the discussions herein. Processing circuitry 112 is provided using any combination of one or more of a suitable central processing unit CPU, multiprocessor, microcontroller, digital signal processor DSP, etc., capable of executing software instructions stored in a computer program product, e.g. in the form of a storage medium 113. The processing circuitry 112 may further be provided as at least one application specific integrated circuit ASIC, 11 or field programmable gate array FPGA. The processing circuitry thus comprises a plurality of digital logic components.

Particulariy, the processing circuitry 112 is configured to cause the control unit 120 to perform a set of operations, or steps to control the operation of the robotic lawn mower 100 including, but not being limited to, controlling the detector transceiver 170, processing measurements results received via the detector transceiver 170, and the propulsion of the robotic lawn mower 100. For example, the storage medium 113 may store the set of operations, and the processing circuitry 112 may be configured to retrieve the set of operations from the storage medium 113 to cause the control unit 120 to perform the set of operations. The set of operations may be provided as a set of executable instructions. Thus, the processing circuitry 112 is thereby arranged to execute at least parts of the methods as herein disclosed.

The storage medium 113 may also comprise persistent storage, which, for example, can be any single one or combination of magnetic memory, optical memory, solid state memory or even remotely mounted memory.

According to some aspects, the control unit 120 further comprises an interface 114 for communications with at least one external device such as a user terminal. As such the interface 114 may comprise one or more transmitters and receivers, comprising analogue and digital components and a suitable number of ports for wireline communication. The interface 114 can be adapted for communication with other devices, such as a remote server, a charging station 215, and/or other robotic lan mowers. Examples of such wireless communication devices are Bluetooth®, WiFi® (lEEE802.1 1 b), Global System Mobile (GSM) and LTE (Long Term Evolution), to name a few.

Figure 8 shows a computer program product 800 comprising computer executable instructions 810 stored on media 820 to execute any of the methods disclosed herein.

With reference to Figure 9, the present disclosure also relates to a method an outdoor robotic work tool 100 adapted for a fon/vard travelling direction D. The method comprises transmitting S100 signals 108a, receiving S200 reflected signals 180b that 12 have been reflected by an object 182 using at least one detector transceiver 170, and determining S300 if an object 182 has been detected by the detector transceiver 170. lf C100 an object 182 has been determined to have been detected, the method comprises determining S400 a detected extension 183, 185 of the object 182 by using the received reflected signals 180b, and determining S500 an estimated continued extension 184 of the object 182.

According to some aspects, the method comprises determining S500 an estimated continued extension 184 of the object 182 by extrapolating S510 the detected extension 183, 185.

According to some aspects, the method comprises determining S500 an estimated continued extension 184 of the object 182 when C200 the detected extension 183, 185 has reached a certain threshold.

According to some aspects, the method comprises determining S500 an estimated continued extension 184 of the object by comparing S520 a first detected extension 183 of the object 182 with a second detected extension 185 of the object 182, adding to the first detected extension 183, where the second detected extension 185 has been determined after the first detected extension 183 has been determined.

According to some aspects, the method comprises controlling S600 the outdoor robotic work tool 100 to slow down.

According to some aspects, the method comprises controlling S700 the outdoor robotic work tool 100 to turn 132 away from the estimated continued extension 184 of the object 182.

According to some aspects, the method comprises controlling S800 the outdoor robotic work tool 100 to position itself in front of the estimated continued extension 184 of the object 182 such that the detector transceiver 170 is enabled to further detect the object 182, such that the control unit 120 is enabled to verify the estimated continued extension 184 of the object 182. by means of multiple detections 13 According to some aspects, the method comprises controlling S810 the outdoor robotic work tool 100 to stop and to then perform a turning movement 100a, 100b such that the detector transceiver 170 is enabled to scan the object 182 by means of multiple detections, such that the control unit 120 is enabled to verify the estimated continued extension 184 of the object 182.

The present disclosure is not limited to the above, but may vary freely within the scope of the appended claims. For example, the robotic lawn mower 100 may comprise both an electric motor arrangement that is powered by a rechargeable electric power source 155, as well as a combustion engine arrangement that is powered by petrol, diesel or some other suitable fuel.

The control unit 120 can be constituted by one or more separate units, according to some aspects the control unit 120 is at least partly comprised in the environmental detection system 110.

The object may have any suitable shape, with reference to Figure 10 that shows a schematic top view of a lawn mower and an object after the first time according to a third example, an arcuate object 182' is shown. There is a detected extension 183', 185' and the estimated continued extension 184' of the object 182' has been determined to follow the arcuate extension of the detected extension 183', 185'. Here, the detected extension 183', 185' comprises a first detected extension 183' and a second detected extension 185', but there may any number of such detected extensions as discussed above.

Claims

1. An outdoor robotic work tool (100) adapted for a forward travelling direction (D) and comprising a control unit (120), an environmental detection system (1 10) that comprises at least one detector transceiver (1 70) adapted to transmit signals (180a) and to receive reflected signals (180b) that have been reflected by an object (182), where the control unit (120) is adapted to determine if an object (182) has been detected by the detector transceiver (170), and if an object (182) has been determined to have been detected, the control unit (120) is adapted to determine a detected extension (183, 185) of the object (182) by means of the received reflected signals (180b), wherein the control unit (120) is adapted to determine an estimated continued extension (184) of the object (182).

2. The outdoor robotic work tool (100) according to claim 1, wherein the control unit (120) is adapted to determine an estimated continued extension (184, 184') of the object (182, 182') by extrapolation of the detected extension (183, 185; 183', 185').

3. The outdoor robotic work tool (100) according to any one of the claims 1 or 2, wherein the control unit (120) is adapted to determine an estimated continued extension (184) of the object (182) when the detected extension (183, 185) has reached a certain threshold.

4. The outdoor robotic work tool (100) according to any one of the previous claims, wherein the control unit (120) is adapted to determine an estimated continued extension (1 84) of the object by comparing a first detected extension (1 83) of the object (182) with a second detected extension (185) of the object (182), adding to the first detected extension (183), where the second detected extension (185) has been determined after the first detected extension (183) has been determined.

5. The outdoor robotic work tool (100) according to any one of the previous claims, wherein the control unit (120) is adapted to control the outdoor robotic work tool (100) to slow down.

6. The outdoor robotic work tool (100) according to any one of the previous claims, wherein the control unit (120) is adapted to control the outdoor robotic work tool (100) to turn (1 32) away from the estimated continued extension (1 84) of the object (182).

7. The outdoor robotic work tool (100) according to any one of the previous claims, wherein the control unit (120) is adapted to control the outdoor robotic work tool (100) to position itself in front of the estimated continued extension (184) of the object (182) such that the detector transceiver (170) is enabled to further detect the object (182), such that the control unit (110) is enabled to verify the estimated continued extension (184) of the object (182).

8. The outdoor robotic work tool (100) according to claim 7, wherein the control unit (120) is adapted to control the outdoor robotic work tool (100) to stop and to then perform a turning movement (100a, 100b) such that the detector transceiver (170) is enabled to scan the object (182) by means of multiple detections, such that the control unit (110) is enabled to verify the estimated continued extension (184) of the object (182).

9. The outdoor robotic work tool (100) according to any one of the previous claims, wherein the robotic work tool (100) is a robotic lawn mower.

10. A method in an outdoor robotic work tool (100) adapted for a forward travelling direction (D), where the method comprises transmitting (S100) signals (108a); receiving (S200) reflected signals (180b) that have been reflected by an object (182) using at least one detector transceiver (170); determining (S300) if an object (182) has been detected by the detector transceiver (170); and if (C100) an object (182) has been determined to have been detected, the method comprises determining (S400) a detected extension (183, 185) of the object (182) by using the received reflected signals (180b); anddetermining (S500) an estimated continued extension (184) of the object (182).

11. The method according to claim 10, wherein the method comprises determining (S500) an estimated continued extension (184) of the object (182) by extrapolating (S510) the detected extension (183, 185).

12. The method according to any one of the c|aims 10 or 11, wherein the method comprises determining (S500) an estimated continued extension (184) of the object (182) when (C200) the detected extension (183, 185) has reached a certain threshold.

13. The method according to any one of the c|aims 10-12, wherein the method comprises determining (S500) an estimated continued extension (1 84) of the object by comparing (S520) a first detected extension (183) of the object (182) with a second detected extension (185) of the object (182), adding to the first detected extension (183), where the second detected extension (185) has been determined after the first detected extension (183) has been determined.

14. The method according to any one of the c|aims 10-13, wherein the method comprises controlling (S600) the outdoor robotic work tool (100) to slow down.

15. The method according to any one of the c|aims 10-14, wherein the method comprises controlling (S700) the outdoor robotic work tool (100) to turn (132) away from the estimated continued extension (184) of the object (182).

16. The method according to any one of the c|aims 10-15, wherein the method comprises controlling (S800) the outdoor robotic work tool (100) to position itself in front of the estimated continued extension (184) of the object (182) such that the detector transceiver (170) is enabled to further detect the object (182), such that the control unit (110) is enabled to verify the estimated continued extension (184) of the object (182).

17. The method according to claims 16, wherein the method comprises controlling (S810) the outdoor robotic work tool (100) to stop and to then perform a turning movement (100a, 100b) such that the detector transceiver (170) is enabled to scan the object (182) by means of multiple detections, such that the control unit (110) is enabled to verify the estimated continued extension (184) of the object (182).