Patent Description:
Systems employing hydraulic steering are common in heavy-duty equipment in general. Hydraulic steering is generally governed by a hydraulic pump and a hydraulic system and control of the hydraulic steering is provided by control of the hydraulic pump and/or the hydraulic system.

A steering system of a road vehicle generally comprise transfer of a mechanical torque between a steering input unit (SIU) and a steering strut. This means that, depending on e.g. a force acting upon the steering strut via wheels of the vehicle and the road, a feedback torque will be provided to the SIU.

A hydraulic steering system of a heavy-duty equipment, specifically an articulated vehicle, is generally electronic. This means that there will be no torque autonomously provided to the SIU.

The feedback torque is advantageous as it e.g., prevents an operator of the SIU from rotating the SIU too fast. A correctly applied feedback torque assists the operator in controlling the vehicle in a safe and smooth manner.

In <CIT>, a controller is connected to sensors on a steering wheel and vehicle steering wheels. The controller is connected to a manual power controller and can control actuators like hydraulic or electric units to steer the wheels. It can also influence brakes and suspension. The controller aims to detect forces on the steering wheels early to control steering sensitivity.

<CIT> describes a steer-by-wire system and control program that prevents excessive turning of a steering handle by increasing steering reaction force when drive electric current to a steering actuator is restrained.

From the above, it is clear that there is a need for improvements.

According to a first aspect of the disclosure, a hydraulic steering system comprising a steering input unit, SIU, and a processing circuitry is presented. The processing circuitry is configured to control a haptic feedback exerted by the SIU. The processing circuitry is configured to obtain an available hydraulic steering capacity of the hydraulic steering system, and control the haptic feedback exerted on the SIU based on the obtained hydraulic steering capacity. The first aspect of the disclosure may seek to improve the haptic feedback provided by an SIU of a vehicle with a hydraulic steering system. A technical benefit may include reducing a risk that a current steering angle of the SIU is not reflected by a current steering angle of the vehicle.

In some examples, including in at least one preferred example, optionally, obtaining the available hydraulic steering capacity comprises obtaining hydraulic operational data of the hydraulic steering system, and determining the available hydraulic steering capacity based on the hydraulic operational data. This is advantageous as it enables a more accurate, safe and/or comfortable steering of a vehicle utilizing the hydraulic steering system.

In some examples, including in at least one preferred example, optionally, the hydraulic operational data comprises a current hydraulic power of the hydraulic steering system. This is advantageous as it enables a more accurate, safe and/or comfortable steering of a vehicle utilizing the hydraulic steering system.

In some examples, including in at least one preferred example, optionally, the hydraulic operational data comprises a current hydraulic flow of the hydraulic steering system. This is advantageous as it enables a more accurate, safe and/or comfortable steering of a vehicle utilizing the hydraulic steering system.

In some examples, including in at least one preferred example, optionally, the hydraulic operational data comprises a current speed of a hydraulic pump driving the hydraulic steering system. This is advantageous as it enables a more accurate, safe and/or comfortable steering of a vehicle utilizing the hydraulic steering system.

In some examples, including in at least one preferred example, optionally, the hydraulic steering system is a steer by wire (SBW) system. This is beneficial as SBW systems allows for precise control over steering, enabling operators to make smaller adjustments and fine-tune their steering inputs. SBW eliminates a need for a mechanical steering linkage, which may be heavy and take up valuable space in the vehicle's design. By using electronic signals to control the steering, the system can be much lighter and more compact, allowing for greater flexibility in vehicle design and reduced fuel consumption due to the reduced weight.

In some examples, including in at least one preferred example, optionally, control of the haptic feedback comprises controlling a torque exerted on the SIU.

In some examples, including in at least one preferred example, optionally, the processing circuitry is further configured to obtain environmental data and control the haptic feedback exerted on the SIU also based on the environmental data. The environmental data comprises one or more of a road condition, a weather condition and/or topology data. This is advantageous as it enables a more accurate, safe and/or comfortable steering of a vehicle utilizing the hydraulic steering system.

According to a second aspect, a vehicle is presented. The vehicle comprises a hydraulic steering system comprising a steering input unit, SIU, and a processing circuitry configured to control a haptic feedback exerted by the SIU. The processing circuitry is configured to obtain an available hydraulic steering capacity of the vehicle, and to control the haptic feedback exerted on the SIU based on the obtained hydraulic steering capacity.

In some examples, including in at least one preferred example, optionally, the hydraulic steering system is the hydraulic steering system of the first aspect.

In some examples, including in at least one preferred example, optionally, the hydraulic steering system comprises at least one hydraulic pump arranged to be driven by a propulsion source of the vehicle.

In some examples, including in at least one preferred example, optionally, at least one hydraulic pump is driven proportionally to a ground speed of the vehicle and the hydraulic operational data comprises a current ground speed of the vehicle.

In some examples, including in at least one preferred example, optionally, at least one hydraulic pump is driven proportionally to a rotational speed of the propulsion source and the hydraulic operational data comprises a current rotational speed of the propulsion source.

In some examples, including in at least one preferred example, optionally, the vehicle is an articulated vehicle.

According to a third aspect, a method of determining a haptic feedback exerted by a SIU of a hydraulic steering system is presented. The method comprises obtaining an available hydraulic steering capacity of the vehicle, and controlling the haptic feedback exerted on the SIU based on the obtained hydraulic steering capacity.

In some examples, including in at least one preferred example, optionally, obtaining the available hydraulic steering capacity comprises obtaining hydraulic operational data of the hydraulic steering system, and determining the available hydraulic steering capacity based on the hydraulic operational data.

In some examples, including in at least one preferred example, optionally, the hydraulic operational data comprises at least one of a current hydraulic power of the hydraulic steering system, a current hydraulic flow of the hydraulic steering system and/or a current speed of a hydraulic pump driving the hydraulic steering system.

The disclosed aspects, examples, and/or accompanying claims may be suitably combined with each other as would be apparent to anyone of ordinary skill in the art.

There are also disclosed herein computer systems, control units, code modules, computer-implemented methods, computer readable media, and computer program products associated with the above discussed technical benefits.

Examples are described in more detail below with reference to the appended drawings.

The detailed description set forth below provides information and examples of the disclosed technology with sufficient detail to enable those skilled in the art to practice the disclosure.

A feedback force of a steering input unit (SIU) is a force operating in a reverse direction of a rotational force applied to the SIU. In a general vehicle, such as a car, there is a direct mechanical link for transfer of steering torque between the SIU and the wheels. This means that an inherent feedback force will be provided from the wheels to the SIU depending on e.g. a speed of the vehicle, road conditions etc. In a steer by wire system (SBW), there is no direct mechanical link for transfer of steering torque between the SIU and the wheels or tracks of the vehicle. In SBW systems, feedback torque to the SIU will be in the form of haptic feedback.

The form of the haptic feedback may depend on a type of SIU utilized. To exemplify, if the SIU is a steering wheel, the haptic feedback may be in the form a feedback torque. If the SIU is a joystick or other controlled, the haptic feedback may be in the form a feedback force.

Providing a correct haptic feedback to an SIU is important not only in order to facilitate control of the vehicle, but also to provide a good working environment for an operator of the vehicle. If a haptic feedback is too high, steering of the vehicle will be heavy, and the vehicle will be uncomfortable to operate. As mentioned, if the haptic feedback is too low, there is a risk of overcompensation of the steering causing unstable and shaky steering of the vehicle.

The steering of a heavy-duty vehicle is a safety critical function. An operator of a heavy-duty vehicle shall be in full control of steering of the vehicle at all times. The steering is advantageously such that the vehicle will react smoothly and responsively to input from the operator. Smoothness is advantageous as it provides an ergonomically sound working environment. Responsiveness is advantageous as it provides full control to the operator. However, smoothness and responsiveness may be contradictive for some use cases.

The inventors behind the present disclosure have identified the requirements of above and, through inventive thinking, realized that there is an opportunity to determine haptic feedback in a hydraulic steering system in a manner that is improved or, at least different, from how haptic feedback has been previously determined. To this end, the present disclosure is concerned with haptic feedback of hydraulic steering systems.

A haptic feedback of a SBW system generally depends on the rotation speed of the SIU. For this to be sufficient, the hydraulic steering system is assumed to always have a same steering capacity, which is not the case. For instance, when an engine driving a hydraulic pump of a hydraulic steering system in a vehicle is running at idle speed, a maximum hydraulic power is generally lower compared to higher engine speed. In this example, the vehicle will have a reduced maximum articulation speed. If the haptic feedback, i.e. a feedback force, of the SIU is not sufficiently high, the vehicle will rotate slower than the SIU indicates. In other words, a current steering angle indicated by the SIU will differ from a current steering angle of the vehicle. To include a factor indicating an available hydraulic steering capacity (e.g. engine speed and vehicle velocity for this example) when calculating the haptic feedback may be beneficial in order to sufficiently counteract rotation of the SIU when the available hydraulic steering capacity is low. Generally, a haptic feedback provided to an SIU of an SBW system is determined as a function of a difference between a current angle of the SIU and a current articulation angle of the vehicle. This methodology is blunt and does not provide an accurate haptic feedback.

When operating an articulated vehicle at high velocities, it is important that the SIU is stabilized to not cause any fast and dangerous articulations. The feedback force of the SIU should therefore also be dependent on the vehicle velocity to increase the feedback force when accelerating.

The teachings may be applied to any vehicle utilizing a hydraulic steering system exemplified by the heavy-duty vehicle <NUM> in the form a truck shown in <FIG>. The vehicle <NUM> comprises at least one propulsion source <NUM>. The propulsion source <NUM> may be an engine and/or a motor arranged to propel the vehicle <NUM>. The vehicle <NUM> according to the present disclosure further comprises a hydraulic steering system <NUM>. The hydraulic steering system <NUM> is configured to control steering of the vehicle <NUM>. The hydraulic steering system <NUM> will be further explained throughout the present disclosure.

In <FIG>, another example of the heavy-duty vehicle <NUM> is shown. In <FIG>, the heavy-duty vehicle <NUM> is an articulated vehicle. An articulated vehicle is a vehicle which has a permanent or semi-permanent pivot j oint in its construction. This pivot j oint allows the articulated vehicle to turn more sharply. There are many kinds of articulated vehicles e.g. heavy-duty equipment, buses, trams, trains etc. In <FIG>, the articulated vehicle is exemplified by an articulated hauler. When articulated vehicles are mentioned, articulated vehicles in general are referred to and not specifically articulated hualers. The vehicle <NUM> of <FIG> also comprises at least one propulsion source <NUM> as above and the hydraulic steering system <NUM>.

With reference to <FIG>, one example of the hydraulic steering system <NUM> according to the present disclosure will be presented. The hydraulic steering system <NUM> comprises a processor circuit <NUM>. The processor circuit <NUM> may be any suitable processor circuit <NUM> and may be a distributed or local circuit and may comprise one or more processor devices or control units.

The processing circuit <NUM> is operatively connected to an SIU <NUM>. The processor circuit <NUM> is configured to control a haptic feedback of the SIU <NUM>. The SIU <NUM> may, in some examples, form part of the hydraulic steering system <NUM>. The SIU <NUM> may be provided with an SIU interface <NUM> configured to facilitate communication between the processor circuit <NUM> and the SIU.

The hydraulic steering system <NUM> further comprises one or more hydraulic pumps <NUM>. These hydraulic pumps <NUM> are configured to drive the hydraulic steering system <NUM>. That is to say, the hydraulic pumps <NUM> are configured to control a flow of hydraulic fluid in the hydraulic system <NUM>. As will be further explained in later sections, the hydraulic pump <NUM> or hydraulic pumps <NUM> may be driven by any suitable power source of the vehicle <NUM>.

The hydraulic steering system <NUM> is configured to control an articulated joint <NUM> of the vehicle <NUM>. The hydraulic steering system <NUM> is hydraulically connected to the articulated joint <NUM>. In some examples, the articulated joint <NUM> is comprised in the hydraulic steering system <NUM>. The articulated joint <NUM> may be any suitable articulated joint <NUM> arranged to control a steering of a vehicle <NUM>. The articulated joint <NUM> may be an articulation joint of the truck <NUM> of <FIG> arranged to control a steering angle of wheel of the truck <NUM>. The articulated joint <NUM> may be an articulation joint of the articulated vehicle <NUM> of <FIG> arranged to control an articulation of the articulated vehicle <NUM>.

The hydraulic steering system <NUM> may further comprise an oil sump <NUM>. The oil sump <NUM> may serves as a reservoir for hydraulic fluid, ensuring that there is a sufficient supply of oil available to the hydraulic steering system <NUM>. This is beneficial at it helps prevent loss of steering control due to low fluid levels. The oil in the oil sump <NUM> also contributes to cooling the hydraulic steering system <NUM> by dissipating heat generated by the movement of the hydraulic fluid through the system. This can help prevent overheating and damage to the hydraulic steering system <NUM>. The oil sump <NUM> may be provided with one or more filtration devices <NUM>. The filtration device <NUM> is advantageously arranged to filter the hydraulic fluid, i.e. the oil. The filter device <NUM> may be arranged to filter the oil upon entry and/or exit from the oil sump <NUM>. The filter device <NUM> is advantageously configured to remove contaminants from the oil, such as dirt, debris, and/or metal shavings. This helps to protect the components of the hydraulic steering system <NUM> from damage and prolongs their life.

The hydraulic steering system <NUM> may further comprise one or more sensor devices <NUM>. The sensor devices <NUM> may be any suitable sensor devices configured to sense, measure, detect or otherwise obtain operational data indicative of operational parameters of the hydraulic steering system. The operational data may will be further explained in further section of the present disclosure.

The skilled person will appreciate that the hydraulic steering system <NUM> presented herein is simplified for efficiency of disclosure. For instance, the SIU <NUM> is generally provided with a suitable torque providing device (e.g. a linear motor etc.). Further to this, gearings, valves etc. may be provided in the hydraulic steering system <NUM>. The skilled person knows how to design a hydraulic steering system and understands what to include in a hydraulic steering system despite it not being mentioned herein. The features mentioned herein are features that contribute to the detailed understanding of the improving features presented herein.

The inventors behind the present disclosure has realized that haptic feedback of the SIU may be controlled based on a capacity of the hydraulic steering system <NUM>. That is to say, the haptic feedback may depend on a current ability of the hydraulic system <NUM> to control the articulated joint <NUM>. To present an extreme example, if the hydraulic pump <NUM> is broken, an available hydraulic steering capacity <NUM> (see <FIG>) will be substantially zero, that is to say, the hydraulic steering system <NUM> will not be able to provide any torque to the articulated joint <NUM>. In such an example, the haptic feedback is advantageously infinite, or at least at a maximum value.

The available hydraulic steering capacity <NUM> may be a measure of an amount of hydraulic power currently available in the hydraulic steering system <NUM>. The available hydraulic steering capacity <NUM> may be determined based one or more factors relating to the operation of the hydraulic steering system <NUM>. As seen in <FIG>, the available hydraulic steering capacity <NUM> may depend on one or more factors in the form of operational data <NUM> of the hydraulic steering system <NUM>.

Current operational data relating to the hydraulic pump <NUM> is advantageously evaluated (by e.g. the sensor device <NUM>) to determine operational data <NUM>.

One exemplary operational data <NUM> may be a current hydraulic pressure (Pa). A hydraulic pressure that the hydraulic steering system <NUM> is currently operating at is a factor that may determine the amount of hydraulic power (steering capacity) available. An increase in hydraulic pressure increases the steering capacity.

Another exemplary operational data <NUM> may be a current hydraulic flow rate (cm<NUM>/s). A current hydraulic flow rate that the hydraulic steering system <NUM> is currently operating at is a factor that may determine the amount of hydraulic power (steering capacity) available. An increase in hydraulic flow rate increases the steering capacity.

Another exemplary operational data <NUM> may be a current capacity of the hydraulic pump <NUM>. The current capacity of the hydraulic pump <NUM> is one factor that may determine the amount of hydraulic power that is available in a hydraulic system. The pump capacity may be indicated in terms of the hydraulic flow rate and the hydraulic pressure. The higher the pump capacity, the more hydraulic power (steering capacity) is available.

A current fluid viscosity is another exemplary operational data <NUM>. The fluid viscosity, or thickness, of the hydraulic fluid used in the hydraulic steering system <NUM> may affect the amount of hydraulic power available. Thicker fluids may reduce the flow rate and increase resistance, which can reduce the amount of hydraulic power (steering capacity) available.

The fluid viscosity may be affected by a temperature of the fluid. A current temperature of the hydraulic fluid is another exemplary operational data <NUM>. Generally, an increase in temperature yields a decreased fluid viscosity which may reduce the amount of hydraulic power (steering capacity) available.

The available hydraulic steering capacity <NUM> may, as indicated above, depend on current operation of the hydraulic pump <NUM>. As shown in <FIG>, the hydraulic pump steering system <NUM> may comprise more than one hydraulic pump 130A, 130B. For safety and redundancy in order to ensure reliable steering, a first hydraulic pump 130A may be driven by a crankshaft <NUM>' (or any other suitable member that rotates proportionally to a rotational speed of the propulsion source <NUM>) of the vehicle <NUM> and second hydraulic pump <NUM>B may be driven by a driveshaft <NUM>'' (or any other suitable member that rotates proportionally to a ground speed of the vehicle <NUM>) of the vehicle <NUM>. The driveshaft <NUM>'' is connected to a gearbox <NUM> of the vehicle <NUM> and located downstream from the gearbox <NUM> such that the gearbox <NUM> is arranged between the driveshaft <NUM>" and the propulsion source <NUM>. The first hydraulic pump 130a will provide a hydraulic pressure proportional to a rotational speed of the propulsion source <NUM>. The higher the rotational speed of the propulsion source <NUM>, the higher the steering capacity <NUM> of the hydraulic steering system <NUM> (and vice versa). The second hydraulic pump 130b will provide a hydraulic pressure proportional to a ground speed of the vehicle <NUM>. The faster the vehicle <NUM> travels, the higher the steering capacity <NUM> of the hydraulic steering system <NUM> (and vice versa).

In <FIG>, the first hydraulic pump 130A may generally be considered a primary hydraulic pump 130A as this will provide a steering capacity <NUM> as long as the propulsion source is running, even if the vehicle <NUM> is stationary. The second hydraulic pump 130B may generally be considered a secondary hydraulic pump 130B as this will only provide a steering capacity <NUM> when the vehicle <NUM> is moving. The secondary hydraulic pump 130B will ensure that a moving vehicle <NUM> may be controlled even if the primary hydraulic pump 130A malfunctions.

In some exemplary embodiments of the hydraulic steering system <NUM>, only one of the first hydraulic pump 130A or the second hydraulic pump 130B is present.

From <FIG>, it may be concluded that the available hydraulic steering capacity <NUM> may be determined based on operational data <NUM> relating to the propulsion source <NUM>. To this end, the operational data <NUM> may comprise a rotational speed (rpm) of the propulsion source <NUM> of the vehicle <NUM>.

From <FIG>, it may further be concluded that the available hydraulic steering capacity <NUM> may be determined based on operational data <NUM> relating to a ground speed of the vehicle <NUM>. To this end, the operational data <NUM> may comprise a current ground speed of the vehicle <NUM>.

As indicated in <FIG>, the hydraulic operational data <NUM> may be comprise data obtained from e.g. the vehicle <NUM> in general, the propulsion source <NUM> of the vehicle <NUM>, the hydraulic steering system <NUM> in general, the hydraulic pump <NUM> of the hydraulic steering system <NUM>, the articulated joint <NUM> of the vehicle <NUM> etc. The hydraulic operational data <NUM> is utilized to determine the available hydraulic steering capacity <NUM> of the vehicle <NUM> and the available hydraulic steering capacity <NUM> is utilized to determine the haptic feedback of the SIU <NUM>.

The inventors behind the present disclosure have further realized that it may be advantageous to utilize further data in order to determine the haptic feedback to be exerted by the SIU <NUM>. Such data may, as shown in <FIG>, comprise environmental data <NUM>. The environmental data <NUM> may be any suitable data describing a current environment of the vehicle. The environmental data <NUM> may be obtained from one or more sensors or devices on board the vehicle <NUM>. Such sensors or devices may be an anti-spin circuitry, a temperature sensor, an inclination sensor, road condition sensor etc. The environmental data <NUM> may comprise weather data obtained by e.g. a communications device <NUM> of the vehicle <NUM> and/or one or more sensors or devices of the vehicle <NUM>. The environmental data <NUM> may comprise topology data <NUM> obtained by e.g. the communications device <NUM> of the vehicle <NUM> and/or one or more sensors or devices on board the vehicle <NUM>.

As previously indicated, the haptic feedback functionality of an SBW system is advantageously used to provide an operator of the vehicle <NUM> with information on a current status of the steering. That is to say, what the current capabilities of the vehicle are and to ensure that the operator is controlling the vehicle <NUM> in a harmless way. The present disclosure has taught the skilled person to comprise more data when determining the haptic feedback in order to give the operator a better understanding of how the vehicle <NUM> may, and should, be handled in every situation. To just base the haptic feedback on the rotational speed of the SIU <NUM> has been tested, evaluated and deemed to be insufficient for most use cases. However, by comprising the steering capacity <NUM> significantly increases the quality of the haptic feedback and reduces, or even removes, a risk that the current steering angle of the SIU does not reflect a current steering angle of the vehicle <NUM>.

In the following, a non-limiting implementation example of the teachings of the present disclosure will be given. Define a rotational speed of the SIU <NUM> as <MAT>, a haptic feedback, i.e. a feedback torque as τfb, a current hydraulic flow as Qhyd(t), the current hydraulic power as Phyd(t) and the vehicle velocity as v(t). The feedback torque τfb(t) may be calculated as <MAT> at each time point t. As mentioned, in hydraulic steering solutions used in some vehicles <NUM>, the hydraulic flow and power depends on a speed of the propulsion source <NUM>. The hydraulic power and flow are used to indicate the hydraulic capacity <NUM> at each time point.

More generally, the steering capacity <NUM> may be defined from the hydraulic flow and power. For other steering solutions, the steering capacity <NUM> may be defined and used to calculate the haptic feedback. If the steering capacity <NUM> is defined as <MAT>,the haptic feedback, i.e. the feedback torque is defined as <MAT> at each time point t.

As mentioned e.g. in reference to <FIG>, the haptic feedback to be provided to the SIU <NUM> may be determined further based on surrounding conditions, i.e. environmental data <NUM>. That is to say, the environmental data <NUM> may describe that the vehicle <NUM> is currently in deep mud which may cause an increase in haptic feedback.

In <FIG>, an exemplary method <NUM> of determining the haptic feedback exerted by an SIU <NUM> is shown. The method <NUM> may be performed by any suitable means. Advantageously, a processor circuit <NUM> as the one previously presented may be configured to cause execution of one or more features of the method <NUM>. In some examples, the processor circuit <NUM> is configured to execute one or more of the features of the method <NUM>. The method <NUM> will be briefly described outlining the main features of the method <NUM>. However, it should be mentioned that the method <NUM> may be amended to comprise any suitable feature or example presented herein.

The method <NUM> comprises obtaining <NUM> the available hydraulic steering capacity <NUM> of the vehicle <NUM>. The available hydraulic steering capacity <NUM> may comprise any indicator and/or data relevant for the steering of the vehicle <NUM> as presented herein. The available hydraulic steering capacity <NUM> may be obtained in any suitable means presented herein.

The method further comprises controlling <NUM> the haptic feedback exerted on the SIU <NUM> based on the obtained hydraulic steering capacity <NUM>. The control of the haptic feedback exerted on the SIU <NUM> may, as previously indicated, be provided by any suitable means acting upon the SIU <NUM>.

Optionally, the method <NUM> may further comprise obtaining <NUM> hydraulic operational data <NUM> of the hydraulic steering system <NUM>, and determining <NUM> the available hydraulic steering capacity <NUM> based on the hydraulic operational data <NUM>. The hydraulic operational data <NUM> may be any suitable hydraulic operational data <NUM> as indicated in the present disclosure.

The method <NUM> is shown in a specific order but this is for illustrative purposes only. The skilled person will appreciate that the order of some features of the method <NUM> may be suitably interchanged.

<FIG> is a schematic diagram of a computer system <NUM> for implementing examples disclosed herein. The computer system <NUM> is adapted to execute instructions from a computer-readable medium to perform these and/or any of the functions or processing described herein. The computer system <NUM> may be connected (e.g., networked) to other machines in a LAN, an intranet, an extranet, or the Internet. While only a single device is illustrated, the computer system <NUM> may include any collection of devices that individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. Accordingly, any reference in the disclosure and/or claims to a computer system, computing system, computer device, computing device, control system, control unit, electronic control unit (ECU), processor device, processing circuitry, etc., includes reference to one or more such devices to individually or jointly execute a set (or multiple sets) of instructions to perform any one or more of the methodologies discussed herein. For example, control system may include a single control unit or a plurality of control units connected or otherwise communicatively coupled to each other, such that any performed function may be distributed between the control units as desired. Further, such devices may communicate with each other or other devices by various system architectures, such as directly or via a Controller Area Network (CAN) bus, etc..

The computer system <NUM> may comprise at least one computing device or electronic device capable of including firmware, hardware, and/or executing software instructions to implement the functionality described herein. The computer system <NUM> may include processing circuitry <NUM> (e.g., processing circuitry including one or more processor devices or control units), a memory <NUM>, and a system bus <NUM>. The computer system <NUM> may include at least one computing device having the processing circuitry <NUM>. The system bus <NUM> provides an interface for system components including, but not limited to, the memory <NUM> and the processing circuitry <NUM>. The processing circuitry <NUM> may include any number of hardware components for conducting data or signal processing or for executing computer code stored in memory <NUM>. The processing circuitry <NUM> may, for example, include a general-purpose processor, an application specific processor, a Digital Signal Processor (DSP), an Application Specific Integrated Circuit (ASIC), a Field Programmable Gate Array (FPGA), a circuit containing processing components, a group of distributed processing components, a group of distributed computers configured for processing, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The processing circuitry <NUM> may further include computer executable code that controls operation of the programmable device.

The system bus <NUM> may be any of several types of bus structures that may further interconnect to a memory bus (with or without a memory controller), a peripheral bus, and/or a local bus using any of a variety of bus architectures. The memory <NUM> may be one or more devices for storing data and/or computer code for completing or facilitating methods described herein. The memory <NUM> may include database components, object code components, script components, or other types of information structure for supporting the various activities herein. Any distributed or local memory device may be utilized with the systems and methods of this description. The memory <NUM> may be communicably connected to the processing circuitry <NUM> (e.g., via a circuit or any other wired, wireless, or network connection) and may include computer code for executing one or more processes described herein. The memory <NUM> may include non-volatile memory <NUM> (e.g., read-only memory (ROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), etc.), and volatile memory <NUM> (e.g., random-access memory (RAM)), or any other medium which can be used to carry or store desired program code in the form of machine-executable instructions or data structures and which can be accessed by a computer or other machine with processing circuitry <NUM>. A basic input/output system (BIOS) <NUM> may be stored in the non-volatile memory <NUM> and can include the basic routines that help to transfer information between elements within the computer system <NUM>.

Computer-code which is hard or soft coded may be provided in the form of one or more modules. The module(s) can be implemented as software and/or hard-coded in circuitry to implement the functionality described herein in whole or in part. The modules may be stored in the storage device <NUM> and/or in the volatile memory <NUM>, which may include an operating system <NUM> and/or one or more program modules <NUM>. All or a portion of the examples disclosed herein may be implemented as a computer program <NUM> stored on a transitory or non-transitory computer-usable or computer-readable storage medium (e.g., single medium or multiple media), such as the storage device <NUM>, which includes complex programming instructions (e.g., complex computer-readable program code) to cause the processing circuitry <NUM> to carry out actions described herein. Thus, the computer-readable program code of the computer program <NUM> can comprise software instructions for implementing the functionality of the examples described herein when executed by the processing circuitry <NUM>. In some examples, the storage device <NUM> may be a computer program product (e.g., readable storage medium) storing the computer program <NUM> thereon, where at least a portion of a computer program <NUM> may be loadable (e.g., into a processor) for implementing the functionality of the examples described herein when executed by the processing circuitry <NUM>. The processing circuitry <NUM> may serve as a controller or control system for the computer system <NUM> that is to implement the functionality described herein.

The computer system <NUM> may include an input device interface <NUM> configured to receive input and selections to be communicated to the computer system <NUM> when executing instructions, such as from a keyboard, mouse, touch-sensitive surface, etc. Such input devices may be connected to the processing circuitry <NUM> through the input device interface <NUM> coupled to the system bus <NUM> but can be connected through other interfaces, such as a parallel port, an Institute of Electrical and Electronic Engineers (IEEE) <NUM> serial port, a Universal Serial Bus (USB) port, an IR interface, and the like. The computer system <NUM> may include an output device interface <NUM> configured to forward output, such as to a display, a video display unit (e.g., a liquid crystal display (LCD) or a cathode ray tube (CRT)). The computer system <NUM> may include a communications interface <NUM> suitable for communicating with a network as appropriate or desired.

The operational actions described in any of the exemplary aspects herein are described to provide examples and discussion. The actions may be performed by hardware components, may be embodied in machine-executable instructions to cause a processor to perform the actions, or may be performed by a combination of hardware and software. Although a specific order of method actions may be shown or described, the order of the actions may differ. In addition, two or more actions may be performed concurrently or with partial concurrence.

It will be further understood that the terms "comprises," "comprising," "includes," and/or "including" when used herein specify the presence of stated features, integers, actions, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, actions, steps, operations, elements, components, and/or groups thereof.

Claim 1:
A hydraulic steering system (<NUM>) comprising a steering input unit, SIU, (<NUM>) and a processing circuitry (<NUM>) configured to control a haptic feedback exerted by the SIU (<NUM>), characterized by the processing circuitry (<NUM>) being configured to:
obtain an available hydraulic steering capacity (<NUM>) of the hydraulic steering system (<NUM>), and
control the haptic feedback exerted on the SIU (<NUM>) based on the obtained hydraulic steering capacity (<NUM>).