Control system for controlling water flow of autonomous drilling rig

Abstract

The present disclosure relates to a control system (1) for controlling a water flow (32) of an autonomous drilling rig (100) comprising: a water pump (30) and a hydraulic motor (40), where the autonomous drilling rig (100) is configured to supply water from the water pump (30) into an airway (20) during drilling, where the control system (1) is configured to: receive a value indicative of a feed rate (FR) of a drill bit (12) during drilling, in response to determining a change in the feed rate (FR), a level of electrical power or current provided to the fluid flow valve (42) is adjusted such that a level of water flow (32) supplied from the water pump (30) into the airway (20) is adjusted. Methods, autonomous drilling machines, computer program products, and non-transitory computer readable media are also disclosed.

Description

TECHNICAL FIELD

[0001] The present disclosure relates to a control system for controlling a water flow of an autonomous drilling rig. The present disclosure further relates to an autonomous drilling rig, a method for controlling a water flow of an autonomous drilling rig, a computer program product and a non-transitory computer readable medium. BACKGROUND

[0002] Rock drilling, i.e. drilling a borehole in rock by excavating rock, is a challenging and demanding operation. During rock drilling, e.g. when drilling using a drill string and a drill bit, drill cuttings are produced at the bottom of the borehole. These drill cuttings need to be removed from the borehole during drilling to ensure an efficient drilling operation.

[0003] Drill cuttings can be removed by flushing, such as by supplying pressurized air into the borehole via an air channel. However, if only air is used, unwanted dust can be produced outside the borehole. Therefore, water can be supplied into the air channel, thereby reducing dust production. When water is supplied into the air channel with the pressurized air, a water mist is produced, whereby the water mist is used to reduce dust production.

[0004] Despite the known use of water in pressurized air to reduce dust levels, there is still an effort to develop improved techniques in relation thereto, especially for autonomous drilling rigs. SUMMARY

[0005] In view of the above, it is an object of the present disclosure to provide an improved control system for controlling a water flow of an autonomous drilling rig, which alleviates one or more of the drawbacks of the prior art in at least one aspect, or at least provides a suitable alternative. It is a further object of the present disclosure to provide an autonomous drilling rig, a method for controlling a water flow of an autonomous drilling rig, a computer program product and a non-transitory computer readable medium, which alleviates one or more of the drawbacks of the prior art in at least one aspect, or at least provides a suitable alternative.

[0006] According to a first aspect of the present disclosure, the object is achieved by a control system according to claim 1. Thus, there is provided a control system for controlling a water flow of an autonomous drilling rig, wherein the autonomous drilling rig comprises:

[0007] a drill string,

[0008] a drill bit,

[0009] an air channel for supplying air to the drill bit,

[0010] a water pump and a hydraulic motor, wherein the hydraulic motor is configured to drive the water pump, and

[0011] The autonomous drilling rig is configured to supply water from a water pump to a gas duct during drilling, and the fluid flow used to drive the hydraulic motor is configured to be controlled based on the level of electrical power or current supplied to the fluid flow valve of the hydraulic motor.

[0012] The control system is configured as follows:

[0013] Receives the value indicating the feed rate of the drill bit during drilling.

[0014] In response to a determined change in the feed rate, the level of electrical power or current supplied to the fluid flow valve is adjusted such that the level of water flow supplied from the pump to the air passage is regulated, wherein the regulation of electrical power or current is based on a predetermined relationship between the level of electrical power or current and the level of water flow supplied by the pump.

[0015] As used herein, an autonomous drilling rig refers to a rig in which at least one adjustable drilling parameter of the drilling operation is automatically controlled. At least one of the adjustable drilling parameters described herein is the flow of water supplied from the pump to the air passage during drilling. Other examples of automatically controllable adjustable drilling parameters include: impact frequency, impact force, drill bit feed rate, drill bit and drill string rotation speeds, static load applied to the drill bit, and air pressure.

[0016] The predetermined relationship is the relationship between the level of electrical power and the level of water flow provided by the pump and / or the relationship between the level of current and the level of water flow provided by the pump.

[0017] By providing a control system as disclosed herein, improved control of water flow during drilling is provided. More specifically, by controlling water flow as disclosed herein, dust generated from drill cuttings during drilling can be reduced while ensuring that excessive water is not supplied to the gas passages. Excessive water can mean reduced drilling performance and / or unnecessary water waste. With this disclosure, no sensors are required for measuring water flow. Instead, water flow can be controlled based on (such as solely on) feed rates and predetermined relationships as disclosed herein. This can mean reliable and robust control, reduced dust generation, cost-effective control, etc.

[0018] Optionally, the control system is further configured to initially set the initial value of the electrical power or current supplied to the fluid flow valve, thereby providing an initial level of water flow from the pump to the air passage. The initial value can be set based on input from the user. The initial value can be set based on the set feed rate at the start of drilling operations. Initially setting the initial value can mean improved control of the water flow, mitigating any unwanted dust generation or water spillage during drilling operation startup.

[0019] Optionally, the initial value of the electrical power or current is set at least in part based on the type of rock that the autonomous drilling rig is about to drill into. It is recognized that the type of rock can affect dust generation. Accordingly, by setting the initial value at least in part based on the type of rock, further improved control of the water flow can be achieved.

[0020] Optionally, the initial value of the electrical power or current is set at least in part based on the condition of the autonomous drilling rig, which indicates the wear state of the drill bit. It is recognized that the wear state of the drill bit can affect dust generation. Accordingly, by setting the initial value at least in part based on the condition of the autonomous drilling rig, which indicates the wear state of the drill bit, further improved control of the water flow can be achieved. For example, the wear state of the drill bit can be determined by using a condition sensor for the drill bit, which measures the wear state of the drill bit. Alternatively, the wear state of the drill bit can be determined based on the previous usage time of the drill bit. For example, the previous usage time can be a value, such as expressed in minutes and / or hours, corresponding to how long the drill bit was previously used in operation.

[0021] Optionally, the control system is further configured to regulate the level of electrical power or current supplied to the fluid flow valve, such that the level of water flow from the pump to the air passage is proportionally adjusted relative to the drill bit feed rate during drilling. Proportional adjustment of the water flow relative to the feed rate has been shown to mitigate dust generation while also preventing water from overflowing into the air passage.

[0022] Optionally, the predetermined relationship between the level of electrical power or current and the level of water flow provided by the pump is nonlinear. For example, the predetermined relationship can be expressed by a nonlinear curve with an increasing derivative. Alternatively, the predetermined relationship can be expressed by a nonlinear curve with a decreasing derivative. This disclosure is further based on the understanding that a nonlinear relationship can exist between the electrical power or current supplied to the fluid flow valve of the hydraulic motor and the level of water flow from the pump driven by the hydraulic motor. Accordingly, by way of example, by using a nonlinear predetermined relationship, the water flow to the air passage can be effectively controlled, mitigating the risk of dust generation while preventing any water from spilling into the air passage.

[0023] According to a second aspect of this disclosure, the objective is achieved by the autonomous drilling rig according to claim 7. Therefore, an autonomous drilling rig is provided, comprising:

[0024] Drill string,

[0025] drill,

[0026] The air passage is used to supply air to the drill bit.

[0027] A water pump and a hydraulic motor, wherein the hydraulic motor is configured to drive the water pump, and

[0028] The autonomous drilling rig is configured to supply water from a water pump to an air passage during drilling, and the fluid flow used to drive the hydraulic motor is configured to be controlled based on the level of electrical power or current supplied to the fluid flow valve of the hydraulic motor.

[0029] The autonomous drilling rig further includes a control system according to any one of the examples of the first aspect of this disclosure.

[0030] The advantages and effects of the second aspect of this disclosure are similar to those of the first aspect. It should also be noted that all embodiments of the first aspect of this disclosure can be combined with all embodiments of the second aspect of this disclosure, and vice versa.

[0031] According to a third aspect of this disclosure, the objective is achieved by the method according to claim 8. Therefore, a method for controlling water flow in an autonomous drilling rig is provided, wherein the autonomous drilling rig comprises:

[0032] Drill string,

[0033] drill,

[0034] The air passage is used to supply air to the drill bit.

[0035] A water pump and a hydraulic motor, wherein the hydraulic motor is configured to drive the water pump, and

[0036] The autonomous drilling rig is configured to supply water from a water pump to a gas duct during drilling, and the fluid flow used to drive the hydraulic motor is configured to be controlled based on the level of electrical power or current supplied to the fluid flow valve of the hydraulic motor.

[0037] The methods include:

[0038] Receives the value indicating the feed rate of the drill bit during drilling.

[0039] In response to a determined change in the feed rate, the level of electrical power or current supplied to the fluid flow valve is adjusted such that the level of water flow supplied from the pump to the air passage is regulated, wherein the regulation of electrical power or current is based on a predetermined relationship between the level of electrical power or current and the level of water flow supplied by the pump.

[0040] The advantages and effects of the third aspect of this disclosure are similar to those of the first and second aspects of this disclosure. It should also be noted that all embodiments of the third aspect of this disclosure can be combined with all embodiments of the first and second aspects of this disclosure, and vice versa.

[0041] Optionally, the method further includes:

[0042] The initial value of the electrical power or current supplied to the fluid flow valve is initially set so that the initial level of water flow from the water pump to the air passage is provided.

[0043] Optionally, the initial value of the electrical power or current is set at least in part based on the type of rock that the autonomous drilling rig is about to drill into.

[0044] Optionally, the initial value of the electrical power or current is set at least in part based on the condition of the autonomous drilling rig, which indicates the wear condition of the drill bit.

[0045] Optionally, adjusting the level of electrical power or current includes adjusting the level of electrical power or current supplied to the fluid flow valve such that the level of water flow supplied from the pump to the air passage is proportional to the feed rate of the drill bit during drilling.

[0046] Optionally, the predetermined relationship between the level of electrical power or current and the level of water flow provided by the pump is non-linear.

[0047] According to the fourth aspect of this disclosure, the objective is achieved by the computer program product according to claim 14. Therefore, a computer program product is provided comprising instructions that cause a control system of any of the examples of the first aspect of this disclosure to perform the steps of the method of any of the examples of the third aspect of this disclosure.

[0048] According to the fifth aspect of this disclosure, the objective is achieved by a non-transitory computer-readable storage medium according to claim 15. Therefore, a non-transitory computer-readable medium is provided having a computer program product stored thereon according to the fourth aspect of this disclosure. Attached Figure Description

[0049] Referring to the accompanying drawings, a more detailed description of embodiments of the present disclosure, cited by way of example, is given below.

[0050] In the attached diagram:

[0051] Fig. 1a This is a schematic diagram of an autonomous drilling rig and control system according to an example of this disclosure.

[0052] Fig. 1b This is a schematic diagram of an autonomous drilling rig and control system according to an example of this disclosure.

[0053] Fig. 2a - Fig. 2b A graph is plotted to represent electrical power or current as a function of water flow, according to examples of this disclosure.

[0054] Fig. 2c A graph is plotted according to an example of this disclosure, expressing the feed rate as a function of water flow.

[0055] Fig. 3It is a flowchart of an example method according to this disclosure, and

[0056] Fig. 4 This is a side view of an autonomous drilling rig according to an example of this disclosure.

[0057] The accompanying drawings are not necessarily drawn to scale. It should also be noted that some details in the drawings may be enlarged to better describe and illustrate particular examples. Unless otherwise stated, the same reference numerals refer to the same elements throughout the description. Detailed Implementation

[0058] Fig. 1a and Fig. 1b An example is depicted of an autonomous drilling rig 100 and a control system 1 for controlling the water flow 32 of the autonomous drilling rig 100.

[0059] Depend on Fig. 1a - Fig. 1b The control system 1 depicted in the box may include a control unit 14, which is an electronic control unit herein. The control unit 14 may include processing circuitry adapted to run a computer program product 16 as disclosed herein. The computer program product 16 may be stored on a non-transitory computer-readable medium 18. The control unit 14 may include hardware and / or software for performing the methods according to this disclosure. In embodiments, the control unit 14 and / or control system 1 may be represented as a computer. The control unit 14 may consist of one or more separate sub-control units. The control system 1 may be an onboard system at least partially located on the autonomous drilling rig 100. Alternatively, the control system 1 may be a non-onboard system adapted to communicate with the autonomous drilling rig 100, for example, via wireless and / or wired communication devices (not shown).

[0060] The 100 self-propelled drilling rig includes:

[0061] Drill string 10,

[0062] Drill bit 12,

[0063] Air passage 20 is used to supply air to drill bit 12.

[0064] Water pump 30 and hydraulic motor 40.

[0065] Drill bit 12 is located at the end of drill string 10. Drill bit 12 can also be referred to as drill bit. Drill string 10 and drill bit 12 are configured to drill borehole 200 by breaking mineral matrix 210.

[0066] The autonomous drilling rig 100 can be configured, for example, to perform impact and / or rotary rock drilling. For example, the hammer (not shown) used to provide the impact force can be air-driven or hydraulically driven. The impact force can be provided, for example, at the top of the drill string 10 or near the drill bit 12.

[0067] Air duct 20 is configured to receive pressurized air from, for example, an air compressor (not shown) of an autonomous drilling rig 100. In this example, the air compressor may also be configured to drive the aforementioned hammer to generate impact force during drilling. Alternatively, the hammer may be hydraulically driven.

[0068] A hydraulic motor 40 is configured to drive a water pump 30, i.e., to cause the water pump 30 to pump water. The hydraulic motor 40 includes a fluid flow valve 42 for driving the hydraulic motor 40. The fluid flow valve 42 can also be referred to as a hydraulic valve. The hydraulic motor 40 is typically driven by hydraulic oil and is configured to convert hydraulic pressure into torque and angular displacement (rotation). The resulting torque and angular displacement are used to drive the water pump 30. The fluid flow valve 42 is configured to control the horizontal and angular displacement of the torque of the hydraulic motor 40.

[0069] The autonomous drilling rig 100 is configured to supply water from the water pump 30 to the air duct 20 during drilling. Fig. 1a - Fig. 1b In the example shown, the air passage 20 is provided inside the drill string 10. However, in other examples, the air passage may be provided outside the drill string. The fluid flow for driving the hydraulic motor 40 is configured to be controlled based on the level of electrical power or current supplied to the fluid flow valve 42 of the hydraulic motor 40. Accordingly, the fluid flow valve 42 is an electro-hydraulic flow valve. The voltage level of the electro-hydraulic flow valve 42 may be, for example, 12V (volts) or 24V.

[0070] Control system 1 is configured as follows:

[0071] The value of the feed rate FR of drill bit 12 during drilling is received. The feed rate FR, or penetration rate, can be expressed, for example, in m / s (meters per second), and is determined by... Fig. 1a - Fig. 1b The downward arrow icon in the image.

[0072] Control system 1 is further configured as follows:

[0073] In response to a change in the feed rate FR, the level of electrical power or current supplied to the fluid flow valve 42 is adjusted such that the level of water flow 32 supplied from the water pump 30 to the air passage 20 is regulated. The adjustment of electrical power or current is based on a predetermined relationship between the level of electrical power or current and the level of water flow 32 supplied by the water pump 30.

[0074] Water flow 32 supplied to air passage 20 will generate water mist in air passage 20 due to pressurized air within it. The pressurized air containing water mist will then be supplied to drill bit 12 within air passage 20, whereby drill cuttings from the drilling operation will mix with the water, thereby mitigating dust generation outside the borehole 200. Air, water, and drill cuttings will be removed from the borehole 200 during drilling, as depicted by arrow 220 pointing upwards from the borehole 200. Accordingly, inFig. 1a - Fig. 1b In the example shown, air, water, and drill cuttings are removed from the borehole 200 outside the drill string 10. However, in other examples, air, water, and drill cuttings may be removed from the borehole 200 in channels within the drill string and / or in channels near the drill string.

[0075] The feed rate FR can be achieved, for example, by using, as Fig. 1b The feed rate sensor 50, as depicted, is used for measurement. For example... Fig. 1b As depicted, the feed rate sensor communicates with the control system 1. Alternatively, the feed rate FR can be determined based on information indicating the power level of the autonomous drilling rig 100 during drilling.

[0076] The control system 1 can be further configured to initially set the initial value of the electrical power or current supplied to the fluid flow valve 42, so that the initial level of water flow 32 supplied from the water pump 30 to the air passage 20 is provided.

[0077] For example, the initial value of electrical power or current can be set, at least in part, based on the type of rock that the autonomous drilling rig 100 is about to drill into. The type of rock can indicate how much dust may be generated during drilling. Therefore, by setting the initial value based on the type of rock at the start of drilling, dust generation can be further mitigated.

[0078] Alternatively, the initial value of the electrical power or current can be set at least in part based on the condition of the autonomous drilling rig 100, which indicates the wear condition of the drill bit 12. For example, the wear condition can be determined using a condition sensor 60 for the drill bit 12, which measures the wear condition of the drill bit. For example, the condition sensor 60 can be configured to measure the length and / or size of the worn parts of the drill bit 12. Fig. 1b As depicted, the condition sensor 60 communicates with the control system 1.

[0079] Fig. 2a - Fig. 2b The electrical power or current P / I supplied to the fluid flow valve 42 is shown in relation to the water flow Wf from the water pump 30 (in Fig. 1a - Fig. 1b Example diagram showing the relationship between (represented as 32) in the figure. Fig. 2c An example graph showing the relationship between feed rate FR and water flow Wf.

[0080] like Fig. 2a - Fig. 2bAs shown, the predetermined relationship between the level of electrical power or current and the level of water flow Wf provided by pump 30 can be non-linear. Correspondingly, the predetermined relationship between the level of current and the level of water flow Wf provided by pump 30 can be non-linear, and / or the predetermined relationship between the level of electrical power and the level of water flow Wf provided by pump 30 can be non-linear. Current I can be expressed in amperes. Electrical power P can be expressed in watts.

[0081] For example, such as Fig. 2a As shown, the predetermined relationship can be expressed by a nonlinear curve C1 with a decreasing derivative. As another example, such as... Fig. 2b As shown, the predetermined relationship can be expressed by a nonlinear curve C2 with an increasing derivative. The predetermined relationship can be determined using empirical testing, simulation, and / or by models describing the characteristics / features of the fluid flow valve 42, hydraulic motor 40, and / or water pump 30. For example, the predetermined relationship can be determined by interpolation between multiple measurement points obtained through empirical testing of the fluid flow valve 42, hydraulic motor 40, and / or water pump 30 during operation. As another example, the predetermined relationship can be determined by interpolation between multiple measurement points obtained by simulating the operation of the fluid flow valve 42, hydraulic motor 40, and / or water pump 30.

[0082] like Fig. 2c As shown, the control system 1 can be further configured to adjust the level of electrical power or current supplied to the fluid flow valve 42 such that the level of water flow Wf supplied from the water pump 30 to the air passage 20 is proportionally adjusted relative to the feed rate FR of the drill bit 12 during drilling. For example, as shown, the proportional relationship can be expressed by a line L1, such as expressed as... , where k is a constant.

[0083] Fig. 3 A flowchart depicts a method for controlling water flow 32 in an autonomous drilling rig 100 according to an example of this disclosure. The autonomous drilling rig 100 can be configured as mentioned above.

[0084] The methods include:

[0085] S1: Receives the value of the feed rate FR of drill bit 12 during drilling, and

[0086] S2: In response to a determined change in the feed rate FR, the level of electrical power or current supplied to the fluid flow valve 42 is adjusted such that the level of water flow 32 supplied from the water pump 30 to the air passage 20 is regulated, wherein the electrical power or current regulation is based on a predetermined relationship between the level of electrical power or current and the level of water flow 32 supplied by the water pump 30.

[0087] The pre-determined relationship can be any of the pre-determined relationships described above.

[0088] like Fig. 3 The method indicated by the dotted box includes:

[0089] S0: Initially set the initial value of the electrical power or current supplied to the fluid flow valve 42 so that the initial level of water flow 32 supplied from the water pump 30 to the air passage 20 is provided.

[0090] The initial value can be set as mentioned above.

[0091] Adjusting the level of electrical power or current may include adjusting the level of electrical power or current supplied to the fluid flow valve 42 such that the level of water flow 32 supplied from the water pump 30 to the air passage 20 is proportional to the feed rate FR of the drill bit 12 during drilling.

[0092] As mentioned above, the predetermined relationship between the level of electrical power or current and the level of water flow 32 provided by the water pump 30 can be a non-linear relationship.

[0093] Fig. 4 An example of an autonomous drilling rig 100 according to this disclosure is depicted. The autonomous drilling rig 100 may also be referred to as autonomous drilling rig 100.

[0094] The 100 self-propelled drilling rig includes:

[0095] Drill string 10,

[0096] Drill bit 12,

[0097] Air passage 20 is used to supply air to drill bit 12.

[0098] A water pump (not shown) and a hydraulic motor (not shown), wherein the hydraulic motor is configured to drive the water pump, and

[0099] The autonomous drilling rig 100 is configured to supply water from a water pump to the air duct 20 during drilling, wherein the fluid flow for driving the hydraulic motor is configured to be controlled based on the level of electrical power or current supplied to the fluid flow valve (not shown) of the hydraulic motor, and

[0100] The autonomous drilling rig 100 further includes a control system 1 according to any one of the examples of the first aspect of this disclosure.

[0101] As shown, the autonomous drilling rig 100 can be a machine without any operator's cab. However, in other examples, the autonomous drilling rig may include an operator's cab.

[0102] The autonomous drilling rig 100 is a drilling rig in which at least one adjustable drilling parameter of the drilling operation is automatically controlled, for example, by a control system 1. At least one of the adjustable drilling parameters herein is the flow 32 of water supplied from the water pump 30 to the air duct 20 during drilling. Other examples of automatically controllable adjustable drilling parameters are: impact frequency, impact force, feed rate FR of the drill bit 12, rotational speed of the drill bit 12 and the drill string 10, static load applied to the drill bit 12, and air pressure supplied to the air duct 20.

[0103] The self-propelled drilling rig 100 can be like Fig. 4 The diagram shows a track component 110 or any other ground engagement device for moving the autonomous drilling rig 100. The autonomous drilling rig 100 may further include one or more hydraulic cylinders 120 for moving / rotating the drill string 10 relative to the body 130 of the autonomous drilling rig 100. Any one of the track component 110, hydraulic cylinders 120, and adjustable drilling parameters may be automatically controlled by the control system 1. The drill string 10 may be connected to the body 130 via a boom 140 and a feed beam 150 attached to the boom 140, as further shown. The feed beam 150 carries a carriage 160, which is slidably arranged along the feed beam 150 to allow the carriage 160 to travel along the feed beam 150. The carriage 160, in turn, carries the drill string 10, thus allowing the drill string 10 to travel along the feed beam 150 by sliding the carriage 160. The carriage 160 may be further automatically controlled by the control system 1. For example, the feed rate FR can be determined based on information indicating the power level used for the sliding carriage 160 during drilling and / or by a sensor (not shown) that measures the feed rate of the carriage 160.

[0104] It should be understood that the present invention is not limited to the embodiments described above and illustrated in the accompanying drawings; rather, those skilled in the art will recognize that many changes and modifications can be made within the scope of the appended claims.

Claims

1. A control system (1) for controlling the water flow (32) of an autonomous drilling rig (100), wherein, The autonomous drilling rig (100) includes: Drill string (10). Drill bit (12). Air passage (20) for supplying air to the drill bit (12), A water pump (30) and a hydraulic motor (40), wherein the hydraulic motor (40) is configured to drive the water pump (30), and The autonomous drilling rig (100) is configured to supply water from the water pump (30) to the air passage (20) during drilling, wherein the fluid flow for driving the hydraulic motor (40) is configured to be controlled based on the level of electrical power or current supplied to the fluid flow valve (42) of the hydraulic motor (40). The control system (1) is configured as follows: Receive the value of the feed rate (FR) of the drill bit (12) during drilling. In response to a change in the feed rate (FR), the level of the electrical power or current supplied to the fluid flow valve (42) is adjusted such that the level of the water flow (32) supplied from the water pump (30) to the air passage (20) is regulated, wherein the regulation of the electrical power or current is based on a predetermined relationship between the level of the electrical power or current and the level of the water flow (32) supplied by the water pump (30).

2. The control system (1) according to claim 1, wherein, The control system (1) is further configured to initially set an initial value for the electrical power or current supplied to the fluid flow valve (42) such that an initial level of water flow (32) supplied from the water pump (30) to the air passage (20) is provided.

3. The control system (1) according to claim 2, wherein, The initial value of the electrical power or current is set at least in part based on the type of rock that the autonomous drilling rig (100) is about to drill into.

4. The control system (1) according to any one of claims 2 or 3, wherein, The initial value of the electrical power or current is set at least in part based on the condition of the autonomous drilling rig (100), which indicates the wear condition of the drill bit (12).

5. The control system (1) according to any one of the preceding claims, wherein, The control system (1) is further configured to adjust the level of the electrical power or current supplied to the fluid flow valve (42) such that the level of the water flow (32) supplied from the water pump (30) to the air passage (20) is adjusted proportionally to the feed rate (FR) of the drill bit (12) during drilling.

6. The control system (1) according to any one of the preceding claims, wherein, The predetermined relationship between the level of electrical power or current and the level of water flow (32) provided by the water pump (30) is a non-linear relationship.

7. An autonomous drilling rig (100), comprising: Drill string (10). Drill bit (12). Air passage (20) for supplying air to the drill bit (12), A water pump (30) and a hydraulic motor (40), wherein the hydraulic motor (40) is configured to drive the water pump (30), and The autonomous drilling rig (100) is configured to supply water from the water pump (30) to the air passage (20) during drilling, wherein the fluid flow for driving the hydraulic motor (40) is configured to be controlled based on the level of electrical power or current supplied to the fluid flow valve (42) of the hydraulic motor (40), and The autonomous drilling rig (100) further includes a control system (1) according to any one of the preceding claims.

8. A method for controlling water flow (32) in an autonomous drilling rig (100), wherein, The autonomous drilling rig (100) includes: Drill string (10). Drill bit (12). Air passage (20) for supplying air to the drill bit (12), A water pump (30) and a hydraulic motor (40), wherein the hydraulic motor (40) is configured to drive the water pump (30), and The autonomous drilling rig (100) is configured to supply water from the water pump (30) to the air passage (20) during drilling, wherein the fluid flow for driving the hydraulic motor (40) is configured to be controlled based on the level of electrical power or current supplied to the fluid flow valve (42) of the hydraulic motor (40). The method includes: The receiver (S1) indicates the value of the feed rate (FR) of the drill bit (12) during drilling. In response to determining a change in the feed rate (FR), the level of the electrical power or current supplied to the fluid flow valve (42) is adjusted (S2) such that the level of the water flow (32) supplied from the water pump (30) to the air passage (20) is regulated, wherein the regulation of the electrical power or current is based on a predetermined relationship between the level of the electrical power or current and the level of the water flow (32) supplied by the water pump (30).

9. The method according to claim 8, wherein, The method further includes: Initially set (S0) to the initial value of the electrical power or current supplied to the fluid flow valve (42) so that the initial level of water flow (32) supplied from the water pump (30) to the air passage (20) is provided.

10. The method according to claim 9, wherein, The initial value of the electrical power or current is set at least in part based on the type of rock that the autonomous drilling rig (100) is about to drill into.

11. The method according to any one of claims 9 or 10, wherein, The initial value of the electrical power or current is set at least in part based on the condition of the autonomous drilling rig (100), which indicates the wear condition of the drill bit (12).

12. The method according to any one of claims 8 to 11, wherein, Adjusting the level of the electrical power or current includes adjusting the level of the electrical power or current supplied to the fluid flow valve (42) such that the level of the water flow (32) supplied from the water pump (30) to the air passage (20) is adjusted proportionally to the feed rate (FR) of the drill bit (12) during drilling.

13. The method according to any one of claims 8 to 12, wherein, The predetermined relationship between the level of electrical power or current and the level of water flow (32) provided by the water pump (30) is a non-linear relationship.

14. A computer program product comprising instructions for causing a control system (1) according to any one of claims 1 to 6 to perform the steps of the method according to any one of claims 8 to 13.

15. A non-transitory computer-readable medium on which a computer program product according to claim 14 is stored.

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