Quadruped robot heat dissipation structure, control method and system

Abstract

This invention discloses a heat dissipation structure, control method, and system for a quadruped robot, belonging to the field of mobile robot technology. The heat dissipation structure includes a main body, a sealable heat dissipation duct, an air inlet chamber, an air outlet chamber, an air inlet fan, an air outlet fan, heat sinks, and heat-conducting plates. The air inlet fan is a centrifugal fan, and the air outlet fan is an axial fan; the two are combined to form a heterogeneous push-pull airflow drive. The heat dissipation duct is physically isolated from the internal electronic component compartment, achieving efficient heat dissipation and high-level dust protection. The heat-conducting plates conduct heat from the actuator motor to the walls of the air inlet / outlet chambers, utilizing the airflow to achieve coupled heat dissipation from multiple heat sources. This invention solves the technical contradictions of low heat dissipation efficiency and interference from multiple heat sources in quadruped robots through heterogeneous fan hierarchical control and structural isolation design.

Description

Technical Field

[0001] This invention relates to the field of mobile robot technology, specifically to the heat dissipation structure, control method, and system of a quadruped robot. Background Technology

[0002] Quadruped robots, with their superior terrain adaptability and mobility, show broad application prospects in fields such as industrial inspection, security patrol, and field exploration. To achieve complex motion control and autonomous navigation, quadruped robots typically integrate high-performance core processors and high-torque-density actuators. These core components generate significant heat under high loads and prolonged operation.

[0003] In existing technologies, the heat dissipation solutions for quadruped robots mainly suffer from the following technical contradictions and defects: In order to achieve a high level of dust and water resistance, the electronic component compartment of the robot is usually designed as a sealed structure. This results in the inability to effectively exchange heat with the outside air, leading to heat accumulation inside, processor frequency reduction, and decreased system stability. The heat sources of quadruped robots are mainly divided into two categories: one is the core processor located inside the body; the other is the distributed actuator motors. Traditional solutions often handle the two types of heat sources separately. For example, the body is cooled by a fan, while the joints rely on natural cooling. This results in a complex and bulky heat dissipation system, and the airflow in the body duct cannot effectively help cool the actuator motors. Although some existing designs have introduced air ducts, they are mostly driven by a single fan, making it difficult to balance air pressure and air volume, and failing to form efficient convection heat exchange in a limited space. Summary of the Invention

[0004] To address the shortcomings of existing technologies, this application provides a heat dissipation structure for a quadruped robot, comprising: Fuselage frame; An air intake compartment is located on one side of the fuselage frame, and an air intake is provided on its side wall; An air vent is located on the other side of the fuselage frame, and its side wall has an air vent. The heat dissipation duct is a sealable structure, located inside the fuselage frame, with its two ends connected to the air intake compartment and the air exhaust compartment, respectively. A heat sink is disposed within the heat dissipation duct for thermal contact with the core processor; An intake fan is disposed between the intake compartment and the heat dissipation duct. An exhaust fan is disposed between the heat dissipation duct and the exhaust chamber.

[0005] Furthermore, it also includes: The first heat-conducting sheet includes multiple sheets, one end of which is thermally coupled to the housing of the quadruped robot's actuator motor, and the other end is thermally coupled to the wall of the air intake chamber or the air exhaust chamber. The second heat-conducting sheet is thermally coupled to the outer wall surface of the heat dissipation duct along the length of the heat dissipation duct.

[0006] Furthermore, both the air intake chamber and the air outlet chamber are located below the heat dissipation duct, the air intake fan is configured as a centrifugal fan, and the air outlet fan is configured as an axial fan.

[0007] Furthermore, the other end of the first heat-conducting sheet is thermally coupled to the inner wall of the air intake chamber or the air outlet chamber, and multiple heat dissipation fins are vertically spaced on the first heat-conducting sheet inside the air intake chamber or the air outlet chamber.

[0008] Furthermore, the heat dissipation structure also includes: A guide member is provided at the air outlet position of the intake fan. The guide member has an upper stop and a side guide. The side guide is arranged to form an air vent along the lower part of the upper stop. The heat sink is provided at the air vent position.

[0009] This application also provides a heat dissipation control method for a quadruped robot, applied to the heat dissipation structure described above, comprising the following steps: S1, real-time acquisition of the core processor temperature T1 and the execution motor position temperature T2; S2, when T1 is greater than the first threshold, start the intake fan and run it at the first speed; S3, when T1 is greater than the second threshold, the exhaust fan is started to run at a second speed higher than the first speed, forming a high-speed directional airflow combining push and pull in the air duct; S4. When T2 is greater than the motor temperature threshold, regardless of whether T1 reaches the first threshold, the intake fan is forcibly started to cool the motor by indirectly conducting airflow to flush the walls of the intake / exhaust chamber.

[0010] Furthermore, if the second threshold is greater than the first threshold, when T1 falls back to between the first threshold and the second threshold, the exhaust fan speed is reduced or its operation is stopped, and only the intake fan is kept running.

[0011] Furthermore, the rate of change of T1 over time is acquired in real time; when the rate of change is greater than a preset temperature rise rate threshold, the exhaust fan is started in advance or the speed of the intake fan is increased to a preset predicted speed to suppress temperature overshoot.

[0012] Furthermore, the rate of change of T2 over time is acquired in real time; when the rate of change is greater than the preset motor temperature rise rate threshold, the intake fan and / or the exhaust fan are started in advance, or the speed of the running fan is increased to the preset predicted speed, so as to suppress the temperature overshoot of the motor.

[0013] As another aspect of this application, a thermal control system for a quadruped robot is also provided, comprising: The temperature acquisition module is used to acquire real-time temperature data of the area where the core processor is located and the temperature data of the motor housing. The controller is configured to execute the control method described above.

[0014] The quadruped robot heat dissipation structure, control method, and system provided in this application have the following beneficial effects: 1. Structural isolation and efficient dust protection: By designing the heat dissipation air duct as a sealable structure, it is physically isolated from the internal electronic component compartment. Outside air only flows within the air duct and does not enter the core circuit area, thereby achieving a high level of dust protection while realizing forced convection heat dissipation. 2. Heterogeneous airflow drive: A centrifugal fan is used as the intake fan to provide high static pressure to overcome the airflow resistance, and an axial fan is used as the exhaust fan to provide high-flow suction. This "push-pull combination" heterogeneous layout ensures high airflow velocity in the airflow duct, which can establish a high-speed, uniform and directional laminar airflow in the narrow heat dissipation airflow duct, so that the heat sink can quickly remove the high heat generated by the core processor and prevent the computing unit from overheating and throttling. 3. Multi-heat source coupled heat dissipation management: The first heat-conducting plate conducts heat from the actuators distributed in each leg to the metal wall of the air intake / exit chamber. When airflow passes through the duct, it continuously washes the inner wall of the chamber and carries away the heat. This design cleverly guides the heat from the distributed heat sources to the centralized air-cooling system, eliminating the need for separate fans for each joint, simplifying system complexity, and solving the problem of multi-heat source interference. 4. Hierarchical Coordinated Control Strategy: Based on the different temperature thresholds of the core processor and the actuator motor, the intake and exhaust fans are independently started, stopped, and their speeds are coordinated. At low loads, only the low-noise, high-efficiency intake fan operates; at high loads, it operates at full speed in a push-pull configuration. It can also respond to joint overheating requests by forcibly activating air cooling, achieving a dynamic balance between thermal management performance and energy consumption / noise. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of one embodiment of the heat dissipation structure for the quadruped robot of this application; Figure 2 for Figure 1 Schematic diagram of the internal structure of the mid-fuselage frame; Figure 3 for Figure 2 Schematic diagram of a local structure in the middle; Figure 4 for Figure 3 Another perspective structural diagram; Figure 5 for Figure 4 Schematic diagram of the guide component structure.

[0016] The markings in the diagram are as follows: 10. Fuselage frame, 11. Actuator motor, 12. Circuit board, 13. CPU, 14. Heat dissipation duct, 15. Cover plate, 16. Heat sink, 17. Air intake compartment, 171. Air intake port, 18. Air intake fan, 19. Guide component, 191. Upper stop, 192. Side guide, 193. Guide opening, 20. Air exhaust compartment, 201. Air exhaust port, 21. Air exhaust fan, 22. First heat conduction plate, 23. Second heat conduction plate. Detailed Implementation

[0017] To enable those skilled in the art to better understand the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative effort should fall within the scope of protection of the present application.

[0018] It should be noted that the terms "first," "second," etc., in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate for the embodiments of this application described herein. Furthermore, the terms "comprising" and "having," and any variations thereof, are intended to cover non-exclusive inclusion; for example, a process, method, system, product, or apparatus that comprises a series of steps or units is not necessarily limited to those steps or units explicitly listed, but may include other steps or units not explicitly listed or inherent to such processes, methods, products, or apparatus.

[0019] In this application, the terms "upper," "lower," "left," "right," "front," "rear," "top," "bottom," "inner," "outer," "middle," "vertical," "horizontal," "lateral," and "longitudinal" indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. These terms are primarily for the purpose of better describing this application and its embodiments, and are not intended to limit the indicated device, element, or component to having a specific orientation, or to be constructed and operated in a specific orientation.

[0020] Furthermore, in addition to indicating location or positional relationship, some of the aforementioned terms may also have other meanings. For example, the term "above" may also be used in some cases to indicate a certain dependency or connection relationship. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0021] Furthermore, the terms "installation," "setup," "equipped with," "connection," "linking," and "socketing" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral structure; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium, or an internal connection between two devices, components, or parts. Those skilled in the art can understand the specific meaning of these terms in this application based on the specific circumstances.

[0022] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. This application will now be described in detail with reference to the accompanying drawings and embodiments. Example

[0023] See Figures 1-5 This embodiment provides a heat dissipation structure for a quadruped robot, mainly including a frame 10. Four sets of actuator motors 11 are installed on the side of the frame 10 for connecting the leg structure of the quadruped robot. The frame adopts an integrated injection molded chassis, which has an installation space inside. Circuit boards 12, CPU 13 and other components are installed in the installation space.

[0024] To achieve heat dissipation for components such as the circuit board and CPU, a heat dissipation duct 14 is provided in the installation space. The heat dissipation duct 14 is located on the longitudinal center line of the chassis frame. It adopts a sealable structure and is sealed at the top with a cover plate 15 to ensure that hot air only flows within the duct. Multiple heat sinks 16 are arranged at intervals along the length of the heat dissipation duct 14 in the middle position. The heat sinks 16 are in close contact with the CPU through a thermally conductive medium (thermal grease or thermal pad) to achieve thermal physical connection.

[0025] Preferably, the heat sink 16 is extruded from high thermal conductivity aluminum material, with a substrate thickness of 2mm and a fin spacing of 15mm, in order to balance air resistance and heat exchange area.

[0026] An air intake chamber 17 is located below one end of the heat dissipation duct 14, positioned between the front and rear actuators without occupying other space. An air inlet 171 is provided on its side wall, and a dust filter (not shown in the figure) can be installed at the air inlet 171 for preliminary filtration of large dust particles. An intake fan 18 is located between the air intake chamber 17 and the heat dissipation duct 14. The intake fan 18 is preferably a high static pressure centrifugal fan with a rated speed of not less than 10,000 RPM.

[0027] To guide the airflow direction of the centrifugal fan, this embodiment also includes a guide member 19. The guide member 19 is located at the air outlet of the intake fan 18. The guide member has an upper stop portion 191 and a side guide portion 192. The upper stop portion 191 prevents the airflow from escaping upwards. The side guide portion 192 surrounds the lower part of the upper stop portion to form a narrow air guide port 193. The air outlet of the centrifugal fan's volute is aligned with the air guide port 193 and is horizontally aligned with the heat dissipation duct. The front end of the heat sink 16 is located near the air guide port. When the airflow is discharged from the centrifugal fan, the guide member straightens the airflow into a horizontally forward, flat, high-speed airflow that directly washes the surface of the heat sink.

[0028] An exhaust chamber 20 is located below the other end of the heat dissipation duct 14. This exhaust chamber is also positioned between the front and rear actuators, and its side wall has an exhaust port 201. It should be noted that the same openings are also present on the chassis frame at the positions corresponding to the air inlet and outlet. An exhaust fan 21 is installed between the exhaust chamber 20 and the heat dissipation duct. The exhaust fan is preferably a high-flow axial fan. Axial fans are characterized by axial airflow, resulting in a large air volume but low static pressure, making them suitable for "suction" at the end of the duct to accelerate airflow discharge.

[0029] To address the overheating issue of the actuator motors, a first heat-conducting plate 22 is installed on the outer casing of each actuator motor. This first heat-conducting plate is made of 0.5mm thick copper, with one end attached to the actuator casing and the other end thermally coupled to the outer wall of the intake or exhaust chamber. Heat from the motor is transferred to the intake and exhaust chambers via the heat-conducting plate. The intake and exhaust chambers can be made of aluminum alloy, which has good thermal conductivity. When airflow passes through the duct, the airflow continuously washes over the inner wall of the chamber, achieving multi-source coupled heat dissipation through the airflow.

[0030] Of course, to enhance the heat dissipation effect, the other end can also be thermally coupled to the inner wall of the air intake or exhaust compartment, or close to the inner wall and parallel to it. The connection between the heat conduction plate and the compartment is sealed. If the heat conduction plate is inside the compartment, the airflow directly washes over the heat conduction plate. At the same time, heat dissipation fins can also be set on the heat conduction plate inside the compartment. The heat dissipation fins are set along the height direction of the compartment to increase the heat exchange area and further enhance the heat dissipation effect at the motor.

[0031] In addition, in order to utilize the metal casing of the heat dissipation duct to assist in heat dissipation, a second heat-conducting plate 23 is provided. The second heat-conducting plate 23 is thermally coupled to the outer wall surface of the heat dissipation duct along the length of the heat dissipation duct, and its two ends are attached to the first heat-conducting plate to further enhance the heat dissipation effect.

[0032] The working principle adopts the working logic of "multi-source thermal coupling + isolated heat exchange": Dual-power air circulation: When the system is working, the centrifugal intake fan at the front end uses its high static pressure to forcefully draw in cool air from the side intake and force it into the air duct, overcoming the resistance caused by the heat sink; the axial exhaust fan at the rear end uses its high flow rate to quickly extract the heated air. This "push-pull" heterogeneous fan combination ensures high-speed, directional airflow within the through-duct.

[0033] Heat exchange of core components: The high temperature generated by the CPU is transferred to the heat sink through conduction, and then carried away by the high-speed cold air in the air duct through forced convection.

[0034] Motor heat dissipation: The heat generated by the motor is transferred to the walls of the inlet / outlet air duct via heat-conducting fins. Because fresh airflow circulates at high speed within the air duct, the walls remove the motor's heat through heat exchange, achieving active and passive coupling heat dissipation between the motor and the air duct.

[0035] Dustproof and sealed protection: The sealed heat dissipation channel ensures that the cooling air flows only within the preset "inlet-duct-exhaust port" path. Even if air containing sand and dust is drawn in, the impurities will only remain in the inlet / outlet air chamber and duct and will not be able to invade the circuit board, thus achieving an extremely high level of protection while dissipating heat. Example

[0036] This embodiment provides a heat dissipation control method for a quadruped robot, specifically including the following steps: Step S1: Real-time acquisition of the core processor temperature T1 and the actuator motor position temperature T2. Thermistors are installed on the core processor substrate and the actuator motor housing for real-time temperature monitoring.

[0037] Step S2: When T1 is detected to be greater than the first threshold (for example, the first threshold is set to 40°C), the controller starts the intake fan to run at the first speed R1 (for example, R1 is 40% of the rated speed). At this time, the exhaust fan remains off. Since only the intake centrifugal fan is working and the speed is low, the airflow flows at a low speed in the duct, resulting in extremely low noise. The heat from the second heat conduction plate and the heat sink is slowly carried away. This stage is suitable for light load scenarios.

[0038] Step S3: When T1 continues to rise and exceeds the second threshold (for example, the second threshold is set to 55°C), the controller starts the exhaust fan to run at the second speed R2, wherein the second threshold is greater than the first threshold and the second speed R2 is higher than the first speed R1 (for example, R2 is 80% of the rated speed).

[0039] At this time, the intake fan and the exhaust fan operate simultaneously, creating a strong push-pull combined negative pressure zone within the cooling airflow duct. Specifically, the intake centrifugal fan overcomes the resistance of the heatsink to establish positive pressure, while the exhaust axial fan creates negative pressure at the end. The combined effect of these two fans significantly increases the airflow velocity through the gaps in the heatsink, quickly suppressing the surge in processor temperature.

[0040] Step S4: In motion mode, the quadruped robot's actuators generally reach high temperatures before the CPU. When the temperature T2 at any actuator position is detected to be greater than the motor temperature threshold (for example, the motor temperature threshold is set to 60°C), the intake fan is forcibly started regardless of whether T1 has reached the first threshold (if it has not been started, it will be started; if it has been started, it will continue to run).

[0041] When T2 exceeds the motor temperature threshold, while T1 remains below the first threshold (i.e., the CPU is still under low temperature and light load), the controller executes a motor-priority cooling mode: the system adjusts the intake fan speed based solely on the difference between T2 and the motor temperature threshold, while the exhaust fan remains off or operates at its lowest speed. In this mode, only the intake fan establishes a unidirectional positive pressure airflow, which flows stably through the intake and exhaust chambers, washing over the first heat-conducting fins and their cooling fins attached to the inner wall of the chamber, thus carrying away the heat transferred from the motor to the chamber through forced convection. Because only a single fan operates, this mode achieves the lowest power consumption and noise levels while ensuring motor cooling.

[0042] As a preferred solution, the control logic is as follows when temperature T1 drops: When T1 falls between the first and second thresholds (e.g., to 45°C), the exhaust fan speed is reduced to stop, and only the intake fan is kept running at a low speed. The intake fan is completely stopped only when T1 falls further to a safe range below the first threshold. This control strategy avoids the fan frequently starting and stopping at the critical temperature point, which would generate noise and current surges.

[0043] In addition to the graded control based on absolute temperature value mentioned above, this method also introduces a predictive feedforward mechanism based on temperature rise rate to intervene in advance when the temperature has risen rapidly before reaching the threshold, thereby suppressing temperature overshoot.

[0044] First, the controller calculates the rate of change of T1 over time in real time. When the rate of change is greater than the preset processor temperature rise rate threshold, even if T1 has not yet reached the second threshold, the controller will start the exhaust fan in advance or increase the speed of the intake fan to the preset second speed R2 in advance, so that the airflow is accelerated in advance and the heat sink is flushed with high airflow before the temperature reaches the dangerous threshold, thereby effectively suppressing the CPU temperature overshoot.

[0045] Secondly, the controller synchronously calculates the rate of change of temperature T2 at each actuator position over time. When the temperature rise rate of any actuator exceeds the preset motor temperature rise rate threshold, even if T2 has not yet reached the motor temperature threshold, the controller will start the intake fan and / or exhaust fan in advance, or increase the speed of the already running fan to the preset predicted speed. This feedforward control targeting the motor heat source can intervene with forced air cooling in advance when the motor heats up rapidly but has not yet reached the overheat protection threshold, preventing the motor temperature inertia overshoot from causing a protective shutdown.

[0046] When the rate of change of T2 is greater than the threshold of the motor temperature rise rate, the following control strategy is adopted first: if neither the intake fan nor the exhaust fan is running at this time, the intake fan is started in advance to pre-cool the motor with unidirectional positive pressure airflow; if the intake fan is running at this time, the intake fan speed is increased simultaneously and the exhaust fan is started to form a high-speed airflow combining push and pull. Example

[0047] This embodiment also provides a heat dissipation control system for a quadruped robot, including: Temperature acquisition module is used to acquire temperature data T1 of the area where the core processor is located and temperature data T2 of the housing of each actuator in real time; The controller can be the robot's main control computer or a microcontroller. The controller 1 stores executable instructions and is configured to execute the logic of each step in the above control method embodiment. The drive module is connected to the intake fan and the exhaust fan respectively, and receives signals from the controller to adjust the fan speed.

[0048] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A heat dissipation structure for a quadruped robot, characterized in that, include: Fuselage frame; An air intake compartment is located on one side of the fuselage frame, and an air intake is provided on its side wall; An air vent is located on the other side of the fuselage frame, and its side wall has an air vent. The heat dissipation duct is a sealable structure, located inside the fuselage frame, with its two ends connected to the air intake compartment and the air exhaust compartment, respectively. A heat sink is disposed within the heat dissipation duct for thermal contact with the core processor; An intake fan is disposed between the intake compartment and the heat dissipation duct. An exhaust fan is disposed between the heat dissipation duct and the exhaust chamber.

2. The heat dissipation structure for a quadruped robot according to claim 1, characterized in that, Also includes: The first heat-conducting sheet includes multiple sheets, one end of which is thermally coupled to the housing of the quadruped robot's actuator motor, and the other end is thermally coupled to the wall of the air intake chamber or the air exhaust chamber. The second heat-conducting sheet is thermally coupled to the wall of the heat dissipation duct along its length.

3. The heat dissipation structure for a quadruped robot according to claim 2, characterized in that: Both the air intake chamber and the air outlet chamber are located below the heat dissipation duct. The air intake fan is configured as a centrifugal fan, and the air outlet fan is configured as an axial fan.

4. The heat dissipation structure for a quadruped robot according to claim 3, characterized in that: The other end of the first heat-conducting plate is thermally coupled to the inner wall of the air intake chamber or the air outlet chamber, and multiple heat dissipation fins are vertically spaced on the first heat-conducting plate inside the air intake chamber or the air outlet chamber.

5. The heat dissipation structure for a quadruped robot according to claim 1, characterized in that, The heat dissipation structure also includes: A guide is provided at the air outlet of the intake fan. The guide has an upper stop and a side guide. The side guide forms an air vent along the lower part of the upper stop. The heat sink is provided at the air vent and multiple fins are arranged at intervals along the length of the heat dissipation duct.

6. A heat dissipation control method for a quadruped robot, applied to the heat dissipation structure according to any one of claims 1 to 5, characterized in that, Includes the following steps: S1, real-time acquisition of the core processor temperature T1 and the execution motor position temperature T2; S2, when T1 is greater than the first threshold, start the intake fan and run it at the first speed; S3, when T1 is greater than the second threshold, the exhaust fan is started to run at a second speed higher than the first speed, forming a high-speed directional airflow combining push and pull in the air duct; S4. When T2 is greater than the motor temperature threshold, regardless of whether T1 reaches the first threshold, the intake fan is forcibly started to cool the motor by indirectly conducting airflow to flush the walls of the intake / exhaust chamber.

7. The heat dissipation control method for a quadruped robot according to claim 6, characterized in that: If the second threshold is greater than the first threshold, when T1 falls back to between the first threshold and the second threshold, the speed of the exhaust fan is reduced or its operation is stopped, and only the intake fan is kept running.

8. The heat dissipation control method for a quadruped robot according to claim 6, characterized in that, Also includes: Real-time acquisition of the rate of change of T1 over time; When the rate of change is greater than the preset temperature rise rate threshold, the exhaust fan is started in advance or the speed of the intake fan is increased to the preset predicted speed to suppress temperature overshoot.

9. The heat dissipation control method for a quadruped robot according to claim 6, characterized in that, Also includes: Real-time acquisition of the rate of change of T2 over time; When the rate of change is greater than the preset motor temperature rise rate threshold, the intake fan and / or the exhaust fan are started in advance, or the speed of the already running fan is increased to the preset predicted speed, in order to suppress the temperature overshoot of the motor.

10. A heat dissipation control system for a quadruped robot, comprising: The temperature acquisition module is used to acquire real-time temperature data of the area where the core processor is located and the temperature data of the motor housing. The controller is configured to perform the control method as described in any one of claims 6-9.

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