Controller and method for hydraulic apparatus

Abstract

To provide a controller for a hydraulic apparatus.SOLUTION: The controller is configured to determine (410) that a mode change criterion has been met for the hydraulic apparatus. In response to the determination, the controller is configured to control (420) a valve arrangement to change a first actuator chamber of a hydraulic actuator between a state of being fluidly connected to a hydraulic machine and fluidly isolated from a second chamber of the hydraulic actuator and a state of being fluidly connected to both the second actuator chamber and the hydraulic machine. Further in response to the determination, the controller is configured to control (430) the hydraulic machine to change a flow rate of hydraulic fluid flowing through the hydraulic machine to regulate a movement of the hydraulic actuator during the control of the valve arrangement.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a controller for a hydraulic device such as a vehicle and a method for controlling such a hydraulic device.

Background Art

[0002] A hydraulic actuator sometimes includes a first hydraulic chamber having a first movable working surface and a second hydraulic chamber having a second movable working surface. Such a hydraulic actuator may be referred to as a double-acting hydraulic actuator. The first hydraulic chamber and the second hydraulic chamber are separated by a movable baffle, and each surface of the movable baffle defines the first and second working surfaces, respectively. In this way, under pressure, the first working surface typically operates to cause movement in a direction opposite to that of the second working surface. Often, the effective working area of the first working surface is different from that of the second working surface. In one example of a double-acting hydraulic actuator as a hydraulic cylinder, the rod extends from the second working surface through the second hydraulic chamber, and the baffle is a piston. As a result, the cross-sectional area of the rod reduces the effective working area of the second hydraulic chamber, which is less than the effective working area of the first hydraulic chamber.

[0003] Sometimes, a hydraulic machine such as a hydraulic pump, a hydraulic motor, or a hydraulic pump motor can be in fluid communication with the first hydraulic chamber, and instead, the second hydraulic chamber can be in fluid communication with a low-pressure hydraulic reservoir. The hydraulic actuator can be moved in a first direction by pumping hydraulic fluid into the first hydraulic chamber, and can be made to move in a second direction opposite to the first direction by being motored by the hydraulic fluid from the first hydraulic chamber. Perhaps, this can be referred to as the "normal" mode.

[0004] In another operating mode, it is known that there is a hydraulic machine that fluidly communicates with both the first and second hydraulic chambers, such that the first hydraulic chamber is in fluid communication with the second hydraulic chamber. This may be referred to as the “differential” mode. In the differential mode, when the hydraulic actuator is operated so that the volume of the first hydraulic chamber decreases, some of the hydraulic fluid from the first hydraulic chamber is directed towards the second hydraulic chamber rather than the hydraulic machine. Since the effective working area of ​​the first hydraulic chamber is larger than that of the second hydraulic chamber, the volume of the second hydraulic chamber increases more slowly than the volume of the first hydraulic chamber decreases. As a result, not all of the hydraulic fluid from the first hydraulic chamber can be directed towards the second hydraulic chamber, and the remainder can be directed towards the hydraulic machine. Thus, it will be understood that when the hydraulic actuator operates in the differential mode, the same flow rate of hydraulic fluid through the hydraulic machine can support faster motion of the hydraulic actuator.

[0005] In differential mode, the maximum load that can be handled by the hydraulic actuator is smaller than when the first hydraulic chamber is fluidly isolated from the second hydraulic actuator.

[0006] This invention is conceived in this context. [Overview of the Initiative] [Means for solving the problem]

[0007] According to one aspect of the present disclosure, a controller for a hydraulic device is provided. The hydraulic device comprises a prime mover, a hydraulic circuit through which a hydraulic fluid can flow, and a hydraulic machine located within the hydraulic circuit and having a rotatable shaft that is drive-engaged with the prime mover. The hydraulic machine is configured such that, during operation, the hydraulic machine exchanges energy with the hydraulic circuit and the prime mover by the motion of the hydraulic fluid between the hydraulic machine and the hydraulic circuit, and by the motion of the rotatable shaft. The hydraulic device further comprises at least one hydraulic actuator having at least a first actuator chamber and a second actuator chamber. Each actuator chamber is located within the hydraulic circuit. At least one hydraulic actuator is used for the hydraulic working function of the hydraulic device. The first actuator chamber is partially defined by a first actuator working surface, and the second actuator chamber is partially defined by a second actuator working surface, the second actuator working surface being positioned to act at least partially opposite to the first actuator working surface. The hydraulic system further comprises a valve device in the hydraulic circuit for selectively routing hydraulic fluid between the first actuator chamber and one or more of the hydraulic machine and the second actuator chamber. The valve device also selectively routes hydraulic fluid between the second actuator chamber and one or more of the first actuator chamber and the low-pressure fluid reservoir.

[0008] The controller is configured to determine that the mode change criteria for the hydraulic device have been met, and in response to that determination, to control the valve device to change between fluidly connecting the first actuator chamber to the hydraulic machine and fluidly isolating it from the second actuator chamber, and fluidly connecting the first actuator chamber to both the second actuator chamber and the hydraulic machine. Furthermore, the controller is configured to change the flow rate of the hydraulic fluid flowing through a portion of the hydraulic circuit that is in fluid communication with the hydraulic machine and the first actuator chamber, thereby controlling the hydraulic machine to adjust the motion (i.e., position or derivative thereof) of at least one hydraulic actuator while controlling the valve device.

[0009] The controller may comprise one or more processors and a memory configured to store instructions, which, when executed by one or more processors, cause the hydraulic device to perform the functions of the controller described herein. The memory may be non-temporary computer-readable memory. The memory may have instructions stored therein. The present invention extends to a non-temporary computer-readable medium (e.g., memory) having instructions stored therein for controlling a device as described herein. The memory may be solid-state memory. The controller may be provided within a single device. In other examples, the controller may be distributed and have multiple processors. The first processor may be isolated from the second processor in a distributed manner.

[0010] Viewed from another aspect, a method is provided for controlling a hydraulic device in order for the controller to operate as configured.

[0011] Specifically, a method for controlling a hydraulic device is provided, the hydraulic device comprising a prime mover, a hydraulic circuit through which a hydraulic fluid can flow, and a hydraulic machine located within the hydraulic circuit and having a rotatable shaft that is drive-engaged with the prime mover. The hydraulic machine is configured such that, during operation, the hydraulic machine exchanges energy with the hydraulic circuit and the prime mover through the flow of hydraulic fluid between the hydraulic machine and the hydraulic circuit, and through the motion of the rotatable shaft. The hydraulic device further comprises at least one hydraulic actuator having at least a first actuator chamber and a second actuator chamber. Each actuator chamber is located within the hydraulic circuit. At least one hydraulic actuator is used for the hydraulic working function of the hydraulic device. The first actuator chamber is partially defined by a first actuator working surface, and the second actuator chamber is partially defined by a second actuator working surface, the second actuator working surface being positioned to act at least partially opposite to the first actuator working surface. The hydraulic device further comprises a valve device in the hydraulic circuit for selectively routing hydraulic fluid between a first actuator chamber and one or more of the hydraulic machine and the second actuator chamber, and for selectively routing hydraulic fluid between the second actuator chamber and one or more of the first actuator chamber and a low-pressure fluid reservoir. The method includes determining that mode change criteria for the hydraulic device have been met, and in response to the determination, controlling the valve device to change the first actuator chamber between being fluidly connected to the hydraulic machine and isolated from the second actuator chamber, and being fluidly connected to both the second actuator chamber and the hydraulic machine. Furthermore, the method includes, in response to the determination, controlling the flow rate of hydraulic fluid flowing through the hydraulic machine and through a portion of the hydraulic circuit that is in fluid communication with the first actuator chamber, thereby regulating the motion of at least one hydraulic actuator while controlling the valve device.

[0012] Therefore, the flow rate of the hydraulic fluid flowing through the hydraulic machine and through the portion of the hydraulic circuit that is in fluid communication with the first actuator chamber can be changed, depending on whether the operating mode of the hydraulic actuator has been changed, specifically whether the first actuator chamber is in fluid communication with the second actuator chamber. In this way, the hydraulic device can be reconfigured between a normal mode and a differential mode during the motion of at least one hydraulic actuator. Of course, there may be very small flow leaks across the baffle between the two actuator chambers, but it will be understood that these are not taken into consideration in providing a fluid connection between the first actuator chamber and the second actuator chamber within the scope of the invention as defined herein.

[0013] A hydraulic system can be any system of multiple components configured to substantially use at least one hydraulic actuator to perform a hydraulic work function. A hydraulic system can be provided as part of a vehicle such as a loader, for example, a wheel loader. Therefore, the present invention extends to vehicles equipped with hydraulic systems.

[0014] A hydraulic machine typically defines multiple working chambers, each within a hydraulic circuit. Each working chamber may be partially defined by the inner surface of a cylinder and a movable working surface mechanically coupled to a rotatable shaft. Typically, the movable working surface is the surface of the piston in a piston-cylinder pair. The volume of each working chamber may change periodically with each rotation of the rotatable shaft. In this way, it will be understood that energy is exchanged between the hydraulic circuit and the prime mover through the motion of one or more movable working surfaces and the rotatable shaft.

[0015] The present invention relates in particular to an electronically rectified hydraulic machine in which active cycles of the working chamber volume are interspersed, with net displacement of the hydraulic working fluid present and inactive cycles of the working chamber volume, with no net displacement of the hydraulic working fluid between the working chamber and the hydraulic circuit. Typically, most or all of the active cycles are full-stroke cycles, and the working chamber displaces a predetermined maximum displacement of the working fluid by suitable control of the timing of valve actuation signals. It is also known that the fraction of the maximum displacement made during the active cycle is adjusted by adjusting one or more low-pressure valves and optionally high-pressure valves of a plurality of working chambers to operate so-called partial-stroke cycles. However, such machines typically intersperse active and inactive cycles instead of operating solely by partial-stroke cycles, where the active cycle is a full-stroke cycle, and the fraction of the cycle that is an active cycle (active cycle fraction) is varied to achieve the required minute displacement.

[0016] The controller may be configured (e.g., programmed) to control the low-pressure valve and optionally the high-pressure valve of the work chamber to cause each work chamber to perform either an active or inactive cycle of the work chamber volume during each cycle of the work chamber volume.

[0017] An "active cycle" refers to a cycle of the working chamber volume that results in a net displacement of the working fluid. An "inactive cycle" refers to a cycle of the working chamber volume that does not result in a net displacement of the working fluid (typically, one or both of the low-pressure and high-pressure valves remain closed throughout the cycle). Typically, active and inactive cycles are interspersed to meet requirements indicated by request signals. This is in contrast to machines that perform only active cycles, in which the displacement can vary.

[0018] Request signals for one or more work chambers of a hydraulic machine are typically processed as a "displacement fraction" Fd, which is the target fraction of the maximum displacement of the working fluid per rotation of the rotatable shaft. Requests expressed in terms of volume (volume of working fluid per second) can be converted to displacement fractions, taking into account the current speed of rotation of the rotatable shaft, as well as the number of work chambers grouped together to the same high-pressure manifold and one or more hydraulic components of the hydraulic system (e.g., at least one hydraulic actuator and one or more further hydraulic components). The request signals relate to requests for the combined fluid displacement of one or more work chambers fluidly connected to the one or more hydraulic components of the hydraulic system via a hydraulic circuit. There may be other groups of one or more work chambers fluidly connected to one or more other hydraulic components, each having its own request signal.

[0019] Presumably, at least the low-pressure valve (optionally a high-pressure valve, or optionally both the low-pressure valve and the high-pressure valve) is an electronically controlled valve, and the controller or further controller is configured to control the valve (e.g., electronically) in phase with respect to the cycle of the working chamber volume, thereby determining the net displacement of the hydraulic fluid by each working chamber for each cycle of the working chamber volume. The method may include controlling the valve (e.g., electronically) in phase with respect to the cycle of the working chamber volume, thereby determining the net displacement of the hydraulic fluid by each working chamber for each cycle of the working chamber volume.

[0020] One or more work chamber groups are dynamically assigned to each group of one or more hydraulic component groups in a hydraulic circuit (e.g., hydraulic actuators and / or one or more further hydraulic component groups), thereby changing which of the one or more work chambers is connected to (e.g., a group of) hydraulic component groups, for example, by opening and closing electronically controlled valves (e.g., high-pressure and low-pressure valves as described herein) under the control of a controller. One or more work chamber groups are assigned to each group of (e.g., one or more) hydraulic component groups, thereby changing which machine's work chamber is coupled to which hydraulic component by opening and / or closing (e.g., electronically controlled) valves, for example, under the control of a controller or further controller. The net displacement of the hydraulic fluid through each work chamber (and / or each hydraulic component) can be adjusted by adjusting the net displacement of one or more work chambers connected to one or more hydraulic component groups. One or more work chamber groups are typically connected to each group of one or more hydraulic component groups through the manifold.

[0021] It is likely that the flow rate of the hydraulic fluid received or output by each working chamber can be controlled independently. It is also likely that the flow of hydraulic fluid received or generated by each working chamber can be controlled independently by selecting the net displacement of the hydraulic fluid by each working chamber for each cycle of the working chamber volume. This selection is typically performed by a controller.

[0022] Typically, a hydraulic machine can operate as a pump in pumping mode or as a motor in motoring mode. Perhaps some of the working chambers of the hydraulic machine can pump (and some working chambers can output hydraulic fluid), while other working chambers of the hydraulic machine can motor (and some working chambers can receive hydraulic fluid).

[0023] The hydraulic machine may be a pump motor. The pump motor may be a digital displacement pump motor. Due to the high efficiency of the digital displacement pump motor, energy transfer between the hydraulic machine and at least one hydraulic actuator is also particularly efficient and more efficient than alternative technologies. It will be further understood that the digital displacement pump motor is particularly suitable for this application due to the possibility of high-speed, precise, and independent control of pressure and flow.

[0024] It will be understood that a valve device may contain substantially any valve in a hydraulic circuit that can affect the fluid flow characteristics of the hydraulic circuit, such as the pressure, flow rate, or route of the hydraulic fluid passing through the hydraulic circuit. Typically, a valve device comprises multiple routing valves. It will be understood that controlling at least one of the multiple routing valves is still considered controlling the valve device.

[0025] The pressure difference between the low-pressure fluid reservoir and atmospheric pressure may be smaller than the pressure difference between the first actuator chamber and atmospheric pressure. The low-pressure fluid reservoir may be open to the atmosphere.

[0026] The volume of hydraulic fluid in the second actuator chamber is supplied by a portion of the hydraulic circuit. The fluid is displaced around the hydraulic circuit, and due to its relatively incompressible nature, fluid injected on one side causes immediate fluid discharge of a different fluid on the other side. This fluid displacement effect is called fluid communication. It reflects the reality that injected fluid causes fluid discharge in another part of the circuit, and this is fluid communication (even if it is not the same actual fluid, i.e., different fluid particles are input compared to their output). Injected fluid particles take time to be transported from the hydraulic circuit to their discharge point, causing displacement of upstream particles.

[0027] The valve device and hydraulic machine may be controlled as described herein during the downward or upward movement of a hydraulic working function in which at least one hydraulic actuator is used.

[0028] The downward movement will be understood to be substantially any movement in which the hydraulic working function operates to cause the hydraulic fluid to flow from the first actuator chamber towards the hydraulic machine. Similarly, the upward movement will be understood to be substantially any movement in which the hydraulic working function performs work caused by the flow of hydraulic fluid from the hydraulic machine towards the first actuator chamber.

[0029] At least one hydraulic actuator may be part of a vertical hydraulic working function. In other words, the hydraulic working function may move in a direction having at least some component in the vertical direction.

[0030] Two actuator chambers may each be part of the same hydraulic actuator. A movable baffle may be provided between the two actuator chambers. In this way, it will be understood that a first actuator working surface is defined on a first side of the movable baffle, and a second actuator working surface is defined on a second side of the movable baffle, opposite the first side.

[0031] In some embodiments, at least one hydraulic actuator may be a plurality of hydraulic actuators, such as two hydraulic actuators. Each hydraulic actuator may have the two actuator chambers described above.

[0032] In this way, it will be understood that at least one hydraulic actuator defines a first effective working area that is the total effective surface area of the first actuator chamber or each of its first actuator working surfaces, and also defines a second effective working area that is the total effective surface area of the second actuator chamber or the working surfaces of each of its second actuators.

[0033] Typically, the first effective working area is larger than the second effective working area, and during the motion of the hydraulic actuator, an imbalance in volume change exists between the first and second actuator chambers, ensuring that this is balanced by fluid flow toward or away from the hydraulic machine. Therefore, at least one hydraulic actuator can operate in differential mode by fluidizing the first actuator chamber with the second actuator chamber. The surface area of ​​the working surface of the first actuator chamber may be larger than the surface area of ​​the working surface of the second actuator chamber. Typically, the rod of the hydraulic actuator may extend through the second chamber of at least one hydraulic actuator to the working surface of the second actuator chamber.

[0034] The determination that the mode change criteria for a hydraulic device have been met may be in response to a speed requirement for the hydraulic work function exceeding a predetermined threshold. Therefore, the mode change criteria may be met if there is a change in the speed requirement that exceeds a predetermined threshold.

[0035] In one example, the requested speed may increase from a first level below a first predetermined threshold to a second level above the first predetermined threshold when at least one hydraulic actuator is operating in normal mode. Typically, the first predetermined threshold is set to be less than or equal to the maximum speed requirement, which can be satisfied by a hydraulic machine fluidly communicating with the first actuator chamber when at least one hydraulic actuator is operating in normal mode (i.e., when the first actuator chamber is fluidly isolated from the second actuator chamber via a hydraulic circuit). Thus, to satisfy the second speed requirement, the hydraulic system is configured to switch the hydraulic actuator from normal mode operation to differential mode operation.

[0036] In another example, the requested speed of a hydraulic work function may decrease from a third speed request, which is higher than a second predetermined threshold, to a fourth speed request, which is lower than the second predetermined threshold, when at least one hydraulic actuator is operating in differential mode. Typically, the second predetermined threshold is set to be greater than or equal to the maximum speed request. Thus, the hydraulic system can be configured to switch the hydraulic actuators from differential mode to normal mode (for example, to increase the load that can be safely supported by the hydraulic work function).

[0037] The second predetermined threshold may differ from the first predetermined threshold. For example, the second predetermined threshold may be greater than the first predetermined threshold. Therefore, when the speed requirement is close to the first predetermined threshold and one of the second predetermined thresholds, the operating mode of the hydraulic actuator will be a form of behavior similar to artificial hysteresis, and will prevent abrupt valve switching based only on very small fluctuations in the speed requirement.

[0038] In response to a determination that the mode change criteria have been met, the valve device may be controlled to change the fluid connection of the first actuator chamber from being fluidly connected to the hydraulic machine and fluidly isolated from the second actuator chamber to another state in which the first actuator chamber is fluidly connected to both the second actuator chamber and the hydraulic machine. In this further state, the flow rate of the hydraulic fluid flowing through the portion of the hydraulic circuit that is in fluid communication with the hydraulic machine and the first actuator chamber may be reduced. Thus, the hydraulic device may be controlled to change the operating mode of at least one hydraulic actuator from normal mode to differential mode.

[0039] In response to a determination that the mode change criteria have been met, the valve device may be controlled to change the fluid connection of the first actuator chamber from fluidly connected to at least one of the plurality of work chambers and the second actuator chamber to another state in which the first actuator chamber is fluidly connected to at least one of the plurality of work chambers and fluidly isolated from the second actuator chamber. In this further state, the flow rate of the hydraulic fluid flowing through the portion of the hydraulic circuit that is in fluid communication with the hydraulic machine and the first actuator may be increased. Thus, the hydraulic device may be controlled to change the operating mode of at least one hydraulic actuator from differential mode to normal mode.

[0040] In some embodiments, the hydraulic machine may comprise a plurality of chamber groups. Each chamber group may comprise at least one working chamber. Each chamber group may be routed independently of at least one other of the plurality of chamber groups in a controllable manner. In this way, one of the plurality of chamber groups can be fluidly connected to at least one hydraulic actuator, while another of the plurality of chamber groups can be fluidly connected to at least one further hydraulic component of the hydraulic system (an additional hydraulic actuator or energy storage component, e.g., a hydraulic accumulator). In some examples, more than one of the chamber groups may be connected to a hydraulic component of the hydraulic system (such as a hydraulic actuator or energy storage component). The chamber groups may also be referred to as pump modules.

[0041] The hydraulic device may include at least one additional hydraulic fluid consumer within the hydraulic circuit. This consumer may be selectively fluidically connected to a hydraulic machine. At least one additional hydraulic fluid consumer may be used for additional hydraulic working functions.

[0042] The determination that the mode change criteria for the hydraulic system have been met may respond to a change in the requirement for further hydraulic work functions. If the requirement for further hydraulic work functions increases, in response to the determination that the mode change criteria have been met, the hydraulic system may be controlled to isolate at least one of several chamber groups of the hydraulic machine from the first actuator chamber of at least one hydraulic actuator. The at least one chamber group is one of at least two of several chamber groups that were previously in fluid communication with the first actuator chamber of at least one hydraulic actuator. In response to the determination that the mode change criteria have been met, the hydraulic system may be further controlled to fluidly communicate at least one chamber group of the hydraulic machine with further hydraulic components used to meet the requirement for further hydraulic work functions. Thus, the hydraulic machine can be reconfigured to assist in meeting the requirement for further hydraulic work functions.

[0043] If the demand from further hydraulic fluid consumers decreases, in response to the determination that the mode change criteria have been met, the hydraulic device may be controlled to isolate at least one of the chamber groups of the hydraulic machine that was previously in fluid communication with further hydraulic components to meet the previous demand for further hydraulic work function, and to fluidly communicate at least one of the multiple chamber groups with the first actuator chamber of at least one hydraulic actuator. Thus, the hydraulic machine can be reconfigured to support the motion demand of at least one hydraulic actuator when there is a reduced demand for further hydraulic work function.

[0044] The determination that the mode change criteria have been met for a hydraulic system may be in response to a change in prime mover speed. As the prime mover decelerates, the velocity of the hydraulic fluid displacement also decreases. Therefore, to continue meeting the speed requirements for the hydraulic work function without increasing the number of chambers of the hydraulic machine that are fluidly communicating with at least one hydraulic actuator, it may be necessary to change at least one hydraulic actuator from normal mode to differential mode. If the prime mover speed increases, the velocity of the hydraulic fluid displacement that can be achieved by at least one of the multiple work chambers also increases. Therefore, it may occur to change at least one hydraulic actuator from differential mode to normal mode while continuing to meet the speed requirements for the hydraulic work function without increasing the number of chambers of the hydraulic machine that are fluidly communicating with at least one hydraulic actuator.

[0045] The valve device may include an actuator chamber connecting valve. The actuator chamber connecting valve may be provided between two actuator chambers in a hydraulic circuit. The actuator chamber connecting valve may be a non-proportional valve.

[0046] It will be understood that non-proportional valves typically have only a few discrete flow states that can be selected, including at least an open state in which the valve is open and allows the flow of hydraulic fluid through it with only slight flow restrictions, if any, and a closed state in which the valve is closed and allows the flow of hydraulic fluid through it in at least one direction. Presumably, the closed state blocks the flow of hydraulic fluid in either direction through the valve. Non-proportional valves typically have fewer than five discrete flow states, such as just two. Thus, the state of the valve can be changed rapidly between opening and closing, which is useful when the mode of at least one hydraulic actuator is changed between normal mode and differential mode during the motion of at least one hydraulic actuator. In other words, non-proportional valves may not allow the selection of one flow state from among the possible continuous flow states.

[0047] The valve device may include a low-pressure fluid reservoir connecting valve, which may be called a tank valve. The low-pressure fluid reservoir may be called a tank, simply labeled, and may or may not be a literal tank. The tank valve may be provided between a second actuator chamber and the tank in the hydraulic circuit. The tank valve may be a non-proportional valve. In a first state, the tank valve may be configured as a one-way valve and may also be a poppet valve. Specifically, in the first state, the tank valve may be configured to substantially block fluid flow from the second actuator chamber through the tank valve to the tank, while allowing fluid flow from the tank through the tank valve to the second actuator chamber. In a second state, the tank valve may be configured as an open valve, allowing fluid flow through it in either direction. The tank valve may include fewer than five flow states. The tank valve may include just two flow states.

[0048] The valve device may include a controllable orifice. The controllable orifice may be selectively configurable to a restricted flow state, allowing a limited amount of hydraulic fluid to pass through it. The controllable orifice may further include an open flow state, allowing more hydraulic fluid to pass through than the restricted flow state. The controllable orifice may be provided between a second actuator chamber and a low-pressure fluid reservoir in the hydraulic circuit. The controllable orifice may also be similar to that of a tank valve.

[0049] A time offset may exist between 1) a change in the valve device and 2) a change in the flow rate of the hydraulic fluid flowing through the hydraulic circuit that is in fluid communication with the hydraulic machine and the first actuator chamber. In other words, a valve control signal to cause a change in the state of one or more valves in the valve device may be provided at a different time than the flow rate control signal to cause a change in the flow rate of the hydraulic fluid flowing through the hydraulic machine. Therefore, if the response speed and operating time of the valves in the valve device differ from those of the valves of the hydraulic machine, the valve control signal can still maintain the smooth motion of the hydraulic working function according to system requirements. The smooth motion of the hydraulic working function is achieved by initiating the change in the state of the valves at a different time than the change in the flow rate of the hydraulic fluid flowing through the hydraulic machine.

[0050] In some cases, the change in the state of the valve gear may begin either before or after the change in displacement value.

[0051] The time offset can be less than 0.5 seconds. The time offset can be less than 200 milliseconds. The time offset can be longer than 10 milliseconds.

[0052] To control the hydraulic machine to change the displacement value in response to a decision, the hydraulic machine may be controlled to implement an intermediate flow rate of the hydraulic fluid flowing through it, and then to implement a further flow rate of the hydraulic fluid flowing through it. Thus, the hydraulic machine may not be controlled to switch instantly between the initial flow rate and the further flow rate, but in some examples it may switch to an intermediate flow rate. As a result, the motion of the hydraulic working function may be regulated more smoothly by taking into account a temporarily substantial pressure difference between the first actuator chamber and the second actuator chamber.

[0053] The intermediate flow rate may be outside the range defined by the initial flow rate and the further flow rate. The further flow rate may be between the initial flow rate and the intermediate flow rate. Therefore, when at least one hydraulic actuator is switched from normal mode to differential mode, the intermediate flow rate of the hydraulic machine can be used to quickly fill a portion of the hydraulic circuit, including the second actuator chamber, with hydraulic fluid having a pressure similar to the hydraulic fluid already present in a portion of the hydraulic circuit, including the first actuator chamber, thereby regulating the motion of the hydraulic working function.

[0054] In some cases, the intermediate flow rate may be zero. The intermediate flow rate may be for purposes such as operating the hydraulic machine in the opposite direction. In other words, if the hydraulic machine was previously motoring, the intermediate flow rate may be for purposes such as preventing the hydraulic machine from pumping, at least temporarily.

[0055] The intermediate flow rate may be in the opposite direction to the further flow rate, and therefore the hydraulic machine pumps the hydraulic fluid toward the second actuator chamber, thereby pressurizing the second actuator chamber.

[0056] Presumably, the controller is configured to operate the hydraulic machine according to a further flow rate in response to determining that the hydraulic pressure in the second actuator chamber meets (e.g., exceeds) a pressure threshold.

[0057] Changes in the flow rate of the hydraulic fluid flowing through the hydraulic machine can be carried out in accordance with a predetermined flow rate limit on the flow rate change. Thus, the flow rate of the hydraulic fluid flowing through the hydraulic machine can be controlled to change without becoming as rapid as possible, as enabled by the predetermined flow rate limit. The predetermined flow rate limit can be stored in memory. The predetermined flow rate limit can be less than the maximum rate of change of flow that is physically possible by the hydraulic machine. Therefore, the rate of change can be controlled to maintain smooth motion of the hydraulic working function during the change of operating mode of at least one hydraulic actuator between normal mode and differential mode.

[0058] A hydraulic actuator can be understood as virtually any hydraulic component for exchanging energy between a pressurized hydraulic fluid and dynamic motion. In other words, a hydraulic actuator can extract energy from a pressurized hydraulic fluid by causing motion of a movable component through the force exerted on the movable component by the pressurized hydraulic fluid. Additionally or alternatively, a hydraulic actuator can extract energy from the motion of a movable component by causing pressurization of the hydraulic fluid through the force exerted on the movable component.

[0059] Dynamic motion can be linear or rotational. In some examples, a hydraulic actuator can be a hydraulic propulsion motor.

[0060] In another aspect, the hydraulic device described above is provided, and it is equipped with the controller also described above.

[0061] Unless otherwise explicitly stated, it will be understood that the methods described herein may also include any of the steps performed by the controller as described elsewhere herein.

[0062] Exemplary embodiments of the present invention will be described with reference to the following figures. [Brief explanation of the drawing]

[0063] [Figure 1] This is a schematic diagram of an example of a hydraulic apparatus described herein. [Figure 2] This is a schematic diagram of a portion of the hydraulic apparatus described herein. [Figure 3] This is a schematic diagram of a vehicle system as an example of the disclosure. [Figure 4] This flowchart illustrates a method for controlling the hydraulic machinery described herein. [Figure 5] This is a schematic diagram of an example of a hydraulic machine. [Modes for carrying out the invention]

[0064] Figure 1 is a schematic diagram of an example of a hydraulic apparatus described herein. The hydraulic apparatus 100 comprises a prime mover 102 and a hydraulic machine 104. The hydraulic machine 104 has a rotatable shaft 106 that is driven-engaged with the prime mover 102. In this embodiment, the hydraulic machine 104 defines a plurality of working chamber groups, in particular five working chamber groups also referred to as chamber groups 108a, 108b, 108c, 108d, and 108e. The detailed operation of the hydraulic machine 104, and in particular the working chamber groups 108a, 108b, 108c, 108d, and 108e, will be further described below with reference to Figure 5. Although not shown in Figure 1, each of the work chamber groups 108a, 108b, 108c, 108d, and 108e typically comprises multiple work chambers within a hydraulic circuit, each work chamber being defined in part by a movable work surface mechanically coupled to a rotatable shaft 106, so that during operation, the hydraulic machine 104 exchanges energy with the hydraulic circuit and prime mover 102 through the motion of the work surface and the rotatable shaft 106.

[0065] It will be understood that the hydraulic circuit is defined by any part of the hydraulic device 100 through which a hydraulic fluid can flow and which is in fluid communication with or can be made to any of the working chambers of the hydraulic machine 104.

[0066] The hydraulic device 100 includes a first hydraulic operation function, in this embodiment a boom lifting operation function 110. The boom lifting operation function 110 uses a first hydraulic actuator 112a and a second hydraulic actuator 112b, each mounted in the form of a cylinder ram between two mutually movable components of the vehicle boom that are moved by the operation of the boom lifting operation function. The first hydraulic actuator 112a includes a first actuator chamber 114a and a second actuator chamber 116a. Similarly, the second hydraulic actuator 112b also includes a first actuator chamber 114b and a second actuator chamber 116b. Each of the actuator chambers 114a, 114b, 116a, and 116b is a hydraulic circuit. The first hydraulic actuator 112a further comprises a piston 118a having a rod 120a extending from there through a second actuator chamber 116a of the first hydraulic actuator 112a. Similarly, the second hydraulic actuator 112b also comprises a piston 118b having a rod 120b extending from there through a second actuator chamber 116b of the second hydraulic actuator 112b. The rod 120a of the first hydraulic actuator 112a is mechanically connected to the rod 120b of the second hydraulic actuator 112b and to the boom 122 such that the motion of one of the hydraulic actuators 112a, 112b, and boom 122 causes the motion of the other of the hydraulic actuators 112a, 112b, and boom 122.

[0067] The actuator valve device 124 is provided in the hydraulic circuit between the first hydraulic actuator 112a and the second hydraulic actuator 112b and the hydraulic machine 104, and is also in fluid communication with the low-pressure fluid reservoir 126. Although not shown in Figure 1, the actuator valve device 124 typically comprises a plurality of valves, each for restricting the flow of fluid through it in at least one direction. At least one of the plurality of valves is controllable to selectively change between at least two operating states. The actuator valve device 124 is in fluid communication with both the first actuator chambers 114a and 114b of the first hydraulic actuator 112a and the second hydraulic actuator 112b, and separately, it is in fluid communication with both the second actuator chambers 116a and 116b of the first hydraulic actuator 112a and the second hydraulic actuator 112b. The actuator valve device 124 can selectively route hydraulic fluid between the first actuator chambers 114a, 114b (located at the bottom of each cylinder ram) and one or more of the hydraulic machine 104 and the second actuator chambers 116a, 116b (located at the top of each cylinder ram) via components of a hydraulic circuit, and can also selectively route hydraulic fluid between the second actuator chambers 116a, 116b and one or more of the first actuator chambers 114a, 114b and the low-pressure fluid reservoir 126 via a hydraulic circuit. In other words, in the first configuration, the actuator valve device 124 is configured to fluidly communicate the first actuator chambers 114a and 114b with the hydraulic machine 104, and to isolate the first actuator chambers 114a and 114b from the second actuator chambers 116a and 116b, instead of fluidly communicating the second actuator chambers 116a and 116b with the low-pressure fluid reservoir 126.In a second configuration, the actuator valve device 124 is configured to fluidly communicate the first actuator chambers 114a and 114b (located at the bottom of the cylinder ram) with the hydraulic machine 104 and the second actuator chambers 116a and 116b, while isolating the low-pressure fluid reservoir 126 from the second actuator chambers 116a and 116b. An exemplary configuration and operation of the actuator valve device 124 are shown and described in more detail below with reference to Figure 2.

[0068] The hydraulic device 100 further comprises a hydraulic mechanical valve device 128 in the form of a manifold arrangement 128. The manifold arrangement 128 comprises a plurality of valves for selectively fluidizing the working chamber of the hydraulic machine 104 to other components of the hydraulic device 100 via a hydraulic circuit.

[0069] Other components include an energy storage component 130 in the form of a hydraulic accumulator 130, and one or more further hydraulic services, in this embodiment, six further hydraulic services 132, 134, 136, 138, 140, and 142. Three of the six further hydraulic services 132, 134, and 136 are controllably fluidically connected to the assembly 128 via a first conduit 144. Three of the six further hydraulic services 138, 140, and 142 are controllably fluidically connected to the assembly 128 via a second conduit 146, separate from the first conduit 144. It will be understood that further valves (not shown in Figure 1) may be fluidly connected between the assembly 128 and each of the further hydraulic services 132, 134, 136, 138, 140, and 142. Each of the additional hydraulic services may also be selectively connected to other hydraulic circuit components, such as the low-pressure fluid reservoir 126, but these connections are omitted for simplicity.

[0070] Figure 1 also includes double-headed dashed arrows illustrating the routing of the hydraulic fluid based on the illustrated configuration of the valves shown in the assembly arrangement 128.

[0071] The hydraulic system 100 further comprises a controller (not shown in Figure 1) configured to control at least the hydraulic machine 104, actuator valve device 124, and assembly 128 of the hydraulic system 100. The operation of the controller will be further described below with reference to Figure 4. In some examples, it will be understood that a hydraulic system can be connected to a separate controller for controlling one or more components of the hydraulic system, but can still be considered a hydraulic system.

[0072] Figure 2 is a schematic diagram of a portion of the hydraulic apparatus described herein. Specifically, the portion 200 of the hydraulic apparatus comprises a first hydraulic actuator 212a and a second hydraulic actuator 212b, each in the form of a cylinder ram and used in a hydraulic working function 210. The first hydraulic actuator 212a comprises a first actuator chamber 214a and a second actuator chamber 216a. Similarly, the second hydraulic actuator 212b also comprises a first actuator chamber 214b and a second actuator chamber 216b. Each of the actuator chambers 214a, 214b, 216a, and 216b is located within a hydraulic circuit 250. The first hydraulic actuator 212a further comprises a piston 218a having a rod 220a extending from there through the second actuator chamber 216a of the first hydraulic actuator 212a. Similarly, the second hydraulic actuator 212b also includes a piston 218b, from which a rod 220b extends through the second actuator chamber 216b of the second hydraulic actuator 212b. Although not shown in Figure 2, typically the rod 220a of the first hydraulic actuator 212a is mechanically connected to the rod 220b of the second hydraulic actuator 212b so that the piston moves together.

[0073] The actuator valve device 224, in the form of an H-bridge 224, is provided within the hydraulic circuit 250 between the first hydraulic actuator 212a and the second hydraulic actuator 212b and the hydraulic machine 204, and is further in fluid communication with the low-pressure fluid reservoir 226.

[0074] The actuator valve device 224 comprises a plurality of valves controllable to operate the hydraulic device as described herein. The hydraulic circuit 250 is formed by a plurality of conduits. The plurality of conduits comprises a first chamber conduit 252 connecting both first actuator chambers 214a, 214b to the actuator valve device 224. The plurality of conduits further comprises a second chamber conduit 254 connecting both second actuator chambers 216a, 216b to the actuator valve device 224. The plurality of conduits further comprises a hydraulic machine conduit 256 connecting a hydraulic machine 204 to the actuator valve device 224, and a low-pressure reservoir conduit 258 connecting a low-pressure fluid reservoir 226 to the actuator valve device 224. The actuator valve device 224 comprises a first valve 260, a second valve 262, a third valve 264, and a fourth valve 266.

[0075] The first valve 260 controls the flow between the second chamber conduit 254 and the low-pressure reservoir conduit 258. In the first position, the first valve 260 is configured to allow hydraulic fluid flow only from the low-pressure reservoir conduit 258 toward the second chamber conduit 254, while substantially blocking the flow of hydraulic fluid from the second chamber conduit 254 toward the low-pressure reservoir conduit 258. In the second position, the first valve 260 is configured to allow hydraulic fluid flow from the second chamber conduit 254 toward the low-pressure reservoir conduit 258. The first valve 260 can be proportionally controlled to implement several different fluid flow rates in the second position.

[0076] The second valve 262 controls the flow between the second chamber conduit 254 and the hydraulic mechanical conduit 256. In the first position, the second valve 262 is configured to allow hydraulic fluid flow only from the second chamber conduit 254 to the hydraulic mechanical conduit 256, while substantially blocking the flow of hydraulic fluid from the hydraulic mechanical conduit 256 to the second chamber conduit 254. In the second position, the second valve 262 is configured to allow hydraulic fluid flow in either direction between the hydraulic mechanical conduit 256 and the second chamber conduit 254. The second valve 262 is solenoid-operated.

[0077] The third valve 264 controls the flow between the first chamber conduit 252 and the hydraulic mechanical conduit 256. In the first position, the third valve 264 is configured to allow hydraulic fluid flow only from the first chamber conduit 252 to the hydraulic mechanical conduit 256, while substantially blocking the flow of hydraulic fluid from the hydraulic mechanical conduit 256 to the first chamber conduit 252. In the second position, the third valve 264 is configured to allow hydraulic fluid flow in either direction between the hydraulic mechanical conduit 256 and the first chamber conduit 252. The third valve 264 is solenoid-operated.

[0078] The fourth valve 266 controls the flow between the first chamber conduit 252 and the low-pressure reservoir conduit 258. In the first position, the fourth valve 266 is configured to allow hydraulic fluid flow only from the low-pressure reservoir conduit 258 towards the first chamber conduit 252, while substantially blocking the flow of hydraulic fluid from the first chamber conduit 252 towards the low-pressure reservoir conduit 258. In the second position, the fourth valve 266 is configured to allow hydraulic fluid flow in either direction between the low-pressure reservoir conduit 258 and the first chamber conduit 252. The fourth valve 266 can be proportionally controlled to implement several different fluid flow rates in the second position.

[0079] Each of the first, second, third, and fourth valves (260, 262, 264, and 266) is an electronically controllable valve that can move between a first position (shown in Figure 2) and a second position.

[0080] The actuator valve device 224 further includes a safety valve 268 that allows the hydraulic mechanical conduit 256 to be directly connected to the low-pressure reservoir conduit 258 in the event of a dangerous pressure buildup in the hydraulic mechanical conduit 256.

[0081] The device further includes a first actuator safety valve 270 and a second actuator safety valve 272, which operate to prevent the first actuator 212a and the second actuator 212b from descending uncontrollably in the event of a failure in the device's electronic control system.

[0082] Figure 3 is a schematic diagram of a vehicle system according to an example of the present disclosure. The vehicle 300 comprises a hydraulic system 310 as described herein, including a hydraulic machine 320 and a controller 330. The controller 330 is configured to exchange signals 325 with the hydraulic machine 320 and to control the hydraulic system 310 according to input signals received by the controller 330, for example, from user input by the operator of the vehicle 300. In this embodiment, the controller 330 is realized by one or more processors 340 and a computer-readable memory 350. The memory 350 stores instructions that, when executed by one or more processors 340, operate the hydraulic system 310 as described herein.

[0083] Although the controller 330 is shown as being part of the vehicle 300, it will be understood that one or more components of the controller 330, or even the controller 330 as a whole, may be provided separately from the vehicle 300, for example, remotely from the vehicle 300, and can exchange signals with the vehicle 300 via wireless communication.

[0084] Figure 4 is a flowchart illustrating a method for controlling a hydraulic machine as described herein. Method 400 is a method for controlling a hydraulic system including a hydraulic machine during a transition of at least one hydraulic actuator between a normal operating mode and a differential operating mode. Specifically, Method 400 includes determining that a mode change criterion for the hydraulic system has been met 410. In other words, the method includes determining, based on one or more parameters, that the operating mode of at least one hydraulic actuator must be transitioned from its current operating mode to a different operating mode (i.e., from a normal mode to a differential mode, or vice versa). As described above, the decision that the operating mode of at least one hydraulic actuator must be changed may depend on one or more of the following: 1) a required speed of the hydraulic actuator, 2) a request for alternative operation of a further hydraulic working function connected to the hydraulic machine, and 3) a change in the shaft speed of the prime mover.

[0085] Method 400 further includes controlling a valve device 420 to change the operating mode of at least one hydraulic actuator between modes in response to a decision. Specifically, to operate at least one hydraulic actuator in normal mode, a first chamber of the hydraulic actuator is fluidically isolated from a second chamber of the hydraulic actuator and fluidly connected to a hydraulic machine. Typically, the second chamber is fluidly connected to a low-pressure fluid reservoir. To operate at least one hydraulic actuator in differential mode, the first chamber of the hydraulic actuator is fluidly connected simultaneously to both the hydraulic actuator and the second chamber of the hydraulic machine.

[0086] Furthermore, in response to the decision, method 400 further includes controlling the hydraulic machine 430 to change the flow rate of hydraulic fluid (e.g., the displacement fraction of the hydraulic machine) flowing through the hydraulic circuit that is in fluid communication with the hydraulic machine and at least one hydraulic actuator. As described above, when changing the operating mode of the actuator from normal to differential, or from differential to normal, the proportion of hydraulic fluid exchanged between the first chamber of the hydraulic actuator and the hydraulic machine changes significantly in a very short time during the motion of the hydraulic actuator. Therefore, the flow rate of hydraulic fluid through the hydraulic machine also needs to be changed to ensure smooth motion of the hydraulic actuator during the transition. Specifically, it is necessary to reduce the flow rate during the transition from the normal operating mode of the hydraulic actuator to the differential operating mode of the hydraulic actuator. Conversely, it is necessary to increase the flow rate during the transition from the differential operating mode of the hydraulic actuator to the normal operating mode of the hydraulic actuator.

[0087] Figure 5 is a schematic diagram of the components of the hydraulic apparatus shown in Figures 1 and 2, showing a single group of working chambers currently connected to one or more hydraulic components (e.g., actuators) through a high-pressure manifold 554. Figure 5 provides details of a first group 500, which comprises a plurality of working chambers (eight shown) having cylinders 524 having a working volume 526 defined by the inner surface of the cylinder, and pistons 528 (providing the working surface 528) driven from a rotatable shaft 530 by an eccentric cam 532, which reciprocate within the cylinder to change the working volume of the cylinder. The rotatable shaft is rigidly connected to the drive shaft and rotates together. A shaft position and speed sensor 534 transmits electrical signals through a signal line 536 to a controller 550, thus enabling the controller to determine the instantaneous angular position and rotational speed of the shaft, and the instantaneous phase of the cycle of each cylinder.

[0088] Each work chamber is associated with a low-pressure valve (LPV) in the form of an electronically operated surface-sealing poppet valve 552 having an associated work chamber, and is also operable to selectively seal channels extending from the work chamber to a low-pressure hydraulic fluid manifold 554 to which one or more work chambers can be connected, or to all as actually shown herein, into the low-pressure hydraulic fluid manifold hydraulic circuit. The LPV is a normally-open solenoid-operated valve which passively opens when the pressure in the work chamber is less than or equal to the pressure in the low-pressure hydraulic fluid manifold, i.e., during the intake stroke, to fluidize the work chamber to the low-pressure hydraulic fluid manifold, but is selectively closable under active control of the controller via the LPV control line 556 to disengage the fluidization of the work chamber to the low-pressure hydraulic fluid manifold. The valve may alternatively be a normally-closed valve. Flow forces due to the passage of fluid across the valve, as well as forces arising from the pressure difference across the valve, also affect the net force on the movable valve member.

[0089] Each work chamber is further associated with a high-pressure valve (HPV) 564, each in the form of a pressure-operated discharge valve. The HPVs open outward from their respective work chambers, and each is operable to seal its respective channel, which extends through a valve block from the work chamber to a high-pressure hydraulic fluid manifold 558, which can connect one or more work chambers, or in fact all of them, as shown in Figure 5. The HPVs function as normally closed pressure-release check valves, passively opening when the pressure in the work chamber exceeds the pressure in the high-pressure hydraulic fluid manifold. The HPVs also function as normally closed solenoid-operated check valves, which the controller can selectively hold open via an HPV control line 562 when the HPV is opened by the pressure in the associated work chamber. Typically, the HPVs are not openable by the controller in relation to the pressure in the high-pressure hydraulic fluid manifold. Additionally, the HPVs may be openable, or partially openable, under the control of the controller when pressure is present in the high-pressure hydraulic fluid manifold but not in the work chambers.

[0090] In pumping mode, the controller selects a net displacement rate of the hydraulic fluid from the work chamber to the high-pressure hydraulic fluid manifold by the hydraulic motor by actively closing one or more LPVs near the point of maximum volume in the associated work chamber cycle, thereby directing the hydraulic fluid through the associated HPVs to the subsequent contraction stroke (but not by actively holding the HPVs open). The controller selects the number and sequence of LPV closures and HPV openings to generate flow or create shaft torque or power to satisfy the selected net displacement rate.

[0091] In motoring operation mode, the controller selects a net displacement rate of the hydraulic fluid displaced through the high-pressure hydraulic fluid manifold and actively closes one or more LPVs just before the minimum volume point of the associated work chamber cycle, closing the path to the low-pressure hydraulic fluid manifold, which compresses the hydraulic fluid in the work chamber by the remainder of the contraction stroke. The associated HPV opens when the pressure across it becomes equivalent, directing a small amount of hydraulic fluid outward through the associated HPV, which is held open by the controller. The controller then typically holds the associated HPV open until near the maximum volume of the associated work chamber cycle, allowing the hydraulic fluid to flow from the high-pressure hydraulic fluid manifold into the work chamber and apply torque to the rotatable shaft.

[0092] Similar to determining on a cycle basis whether the LPV remains open or open, the controller can be operated to vary the precise phase of HPV closure for different working chamber volumes, thereby selecting a net displacement rate from high pressure to low pressure hydraulic fluid manifold, or vice versa.

[0093] The arrows on the low-pressure fluid connection 506 and the high-pressure fluid connection 521 indicate the hydraulic fluid flow in motoring mode, while the flow reverses in pumping mode. The pressure relief valve 566 can protect the first group from damage.

[0094] Under normal operation, the active and inactive cycles of the working chamber volume are intermittently used to meet the requirements indicated by the hydraulic mechanical control signals.

[0095] Throughout this specification and the claims, the terms “composes,” “includes,” and their variations mean “includes but not limited to,” and they are not intended to exclude, nor do they exclude, other components, integers, or steps. Throughout this specification and the claims, the singular form includes the plural form unless otherwise required by context. In particular, where the indefinite article is used, the specification should be understood to evoke both the singular and plural forms unless otherwise required by context.

[0096] Features, integers, characteristics, or groups described in conjunction with specific aspects, embodiments, or examples of the present invention should be understood to be applicable to any other aspects, embodiments, or examples described herein, provided they do not conflict with each other. All features and / or all steps of any method or process disclosed herein (including any appended claims, abstract, and drawings) can be combined in any combination, except for any combination in which at least some of such features and / or steps are mutually exclusive. The present invention is not limited to any of the details of any of the embodiments described herein. The present invention extends to any novel features or any novel combination of features disclosed herein (including any appended claims, abstract, and drawings), or to any novel steps or any novel combination of steps of any method or process disclosed herein.

Claims

1. 1. A controller for a hydraulic device, the hydraulic device comprising: The prime mover and a hydraulic circuit through which hydraulic fluid can flow; a hydraulic machine within the hydraulic circuit and having a rotatable shaft in driving engagement with the prime mover, wherein during operation the hydraulic machine is configured to exchange energy with the hydraulic circuit and the prime mover by flow of hydraulic fluid between the hydraulic machine and the hydraulic circuit and through movement of the rotatable shaft; at least one hydraulic actuator having at least a first actuator chamber and a second actuator chamber, each actuator chamber being in the hydraulic circuit, the at least one hydraulic actuator being used in a hydraulic work function of the hydraulic device, the first actuator chamber being partially defined by a first actuator work surface and the second actuator chamber being partially defined by a second actuator work surface, the second actuator work surface being arranged to act at least partially in opposition to the first actuator work surface; a valve arrangement in the hydraulic circuit for selectively routing the hydraulic fluid between the first actuator chamber and one or more of the hydraulic machine and the second actuator chamber, and for selectively routing the hydraulic fluid between the second actuator chamber and one or more of the first actuator chamber and a low pressure fluid reservoir, wherein the controller determining that a mode change criterion for the hydraulic system has been met; In response to said determination, controlling the valve arrangement to change the first actuator chamber between being fluidly connected to the hydraulic machine and fluidly isolated from the second actuator chamber, and being fluidly connected to both the second actuator chamber and the hydraulic machine; and controlling the hydraulic machine to vary a flow rate of hydraulic fluid flowing through a portion of the hydraulic circuit that is in fluid communication with the hydraulic machine and the first actuator chamber, thereby regulating movement of the at least one hydraulic actuator during the control of the valve arrangement; the hydraulic machine comprises a plurality of chamber groups each comprising at least one working chamber in the hydraulic circuit, the hydraulic device comprises at least one further hydraulic fluid consumer in the hydraulic circuit and selectively fluidly connected to the hydraulic machine, the at least one further hydraulic fluid consumer being used in a further hydraulic work function, the determination that the mode change criteria of the hydraulic device have been met is responsive to an increase in demand for the further hydraulic work function, and in response to the determination, the hydraulic device is controlled to isolate at least one chamber group of the hydraulic machine from the first actuator chamber of the at least one hydraulic actuator, the at least one chamber group being among at least two of the plurality of chamber groups that were previously in fluid communication with the first actuator chamber of the at least one hydraulic actuator.

2. 1. A method of controlling a hydraulic device, the method comprising: The prime mover and a hydraulic circuit through which hydraulic fluid can flow; a hydraulic machine within the hydraulic circuit and having a rotatable shaft in driving engagement with the prime mover, wherein during operation the hydraulic machine is configured to exchange energy with the hydraulic circuit and the prime mover by flow of hydraulic fluid between the hydraulic machine and the hydraulic circuit and through movement of the rotatable shaft; at least one hydraulic actuator having at least a first actuator chamber and a second actuator chamber, each actuator chamber being in the hydraulic circuit, the at least one hydraulic actuator being used in a hydraulic work function of the hydraulic device, the first actuator chamber being partially defined by a first actuator work surface and the second actuator chamber being partially defined by a second actuator work surface, the second actuator work surface being arranged to act at least partially in opposition to the first actuator work surface; a valve arrangement in the hydraulic circuit for selectively routing the hydraulic fluid between the first actuator chamber and one or more of the hydraulic machine and the second actuator chamber, and for selectively routing the hydraulic fluid between the second actuator chamber and one or more of the first actuator chamber and a low pressure fluid reservoir, the method comprising: determining that a mode change criterion for the hydraulic system has been met; In response to said determination, controlling the valve arrangement to vary the first actuator chamber between fluidly connecting the first actuator chamber to the hydraulic machine and fluidly isolating the first actuator chamber from the second actuator chamber, and fluidly connecting the first actuator chamber to both the second actuator chamber and the hydraulic machine; controlling the hydraulic machine to vary a flow rate of hydraulic fluid flowing through a portion of the hydraulic circuit in fluid communication with the hydraulic machine and the first actuator chamber, thereby regulating movement of the at least one hydraulic actuator during the control of the valve arrangement; the hydraulic machine comprises a plurality of chambers, each chamber comprising at least one working chamber in the hydraulic circuit; the hydraulic device comprises at least one further hydraulic fluid consumer in the hydraulic circuit and selectively fluidly connected to the hydraulic machine; the at least one further hydraulic fluid consumer is used in a further hydraulic work function; the determination that the mode change criterion of the hydraulic device has been met is in response to an increase in demand for the further hydraulic work function; and in response to the determination, the hydraulic device is controlled to isolate at least one chamber of the hydraulic machine from the first actuator chamber of the at least one hydraulic actuator, the at least one chamber being among at least two of the plurality of chambers that were previously in fluid communication with the first actuator chamber of the at least one hydraulic actuator.

3. 2. The controller of claim 1, wherein the valve arrangement and the hydraulic machine are controlled during a downward movement of the hydraulic work function in which the at least one hydraulic actuator is used, or the valve arrangement and the hydraulic machine are controlled during an upward movement of the hydraulic work function in which the at least one hydraulic actuator is used.

4. The controller of claim 1 , wherein a surface area of ​​the first actuator work surface is greater than a surface area of ​​the second actuator work surface.

5. The controller of claim 1 , wherein the determination that the mode change criteria for the hydraulic system have been met is in response to a speed demand for the hydraulic work function exceeding a predetermined threshold.

6. 2. The controller of claim 1, wherein in response to the determination, the valve arrangement is controlled to change from fluidly connecting the first actuator chamber to the hydraulic machine and fluidly isolating it from the second actuator chamber to fluidly connecting the first actuator chamber to both the second actuator chamber and the hydraulic machine, and the hydraulic machine is controlled to reduce a flow rate of hydraulic fluid flowing through the portion of the hydraulic circuit that is in fluid communication with the hydraulic machine and the first actuator chamber.

7. 2. The controller of claim 1, wherein in response to the determination, the valve arrangement is controlled to change the first actuator chamber from fluidly connecting the first actuator chamber to both the second actuator chamber and the hydraulic machine to fluidly connecting the first actuator chamber to the hydraulic machine and fluidly isolating the first actuator chamber from the second actuator chamber, and the hydraulic machine is controlled to increase a flow rate of hydraulic fluid flowing through the portion of the hydraulic circuit that is in fluid communication with the hydraulic machine and the first actuator chamber.

8. 2. The controller of claim 1, wherein the valve arrangement comprises an actuator chamber connection valve provided in the hydraulic circuit between the first actuator chamber and the second actuator chamber, the actuator chamber connection valve being a non-proportional valve.

9. The controller of claim 1 , wherein the hydraulic machine is an electronically commutated hydraulic machine.

10. 2. The controller of claim 1, wherein there is a time offset between the alteration of the valve arrangement and the alteration of the flow rate of the hydraulic fluid flowing through the portion of the hydraulic circuit that is in fluid communication with the hydraulic machine and the first actuator chamber, optionally the time offset being less than 0.5 seconds.

11. 2. The controller of claim 1, wherein in response to the determination, to control the hydraulic machine to vary the flow rate, the hydraulic machine is controlled to implement an intermediate flow rate of the hydraulic fluid flowing through the hydraulic machine and thereafter implement a further flow rate of the hydraulic fluid flowing through the hydraulic machine.

12. 12. The controller of claim 11, wherein the intermediate flow rate is in an opposite direction to the further flow rate such that the hydraulic machine pumps hydraulic fluid toward the second actuator chamber causing pressurization of the second actuator chamber.

13. The controller of claim 1 , wherein the change in the flow rate of the hydraulic fluid flowing through the hydraulic machine is implemented in response to a predetermined flow rate limit of a change in displacement value.

14. A hydraulic device, The prime mover and a hydraulic circuit through which hydraulic fluid can flow; a hydraulic machine within the hydraulic circuit and having a rotatable shaft in driving engagement with the prime mover, wherein during operation the hydraulic machine exchanges energy with the hydraulic circuit and the prime mover by movement of the hydraulic fluid between the hydraulic machine and the hydraulic circuit and through movement of the rotatable shaft; at least one hydraulic actuator having at least a first actuator chamber and a second actuator chamber, each actuator chamber being in the hydraulic circuit, the at least one hydraulic actuator being used in a hydraulic work function of the hydraulic device, the first actuator chamber being partially defined by a first actuator work surface and the second actuator chamber being partially defined by a second actuator work surface, the second actuator work surface being arranged to act at least partially in opposition to the first actuator work surface; a valve arrangement in the hydraulic circuit for selectively routing the hydraulic fluid between the first actuator chamber and one or more of the hydraulic machine and the second actuator chamber, and for selectively routing the hydraulic fluid between the second actuator chamber and one or more of the first actuator chamber and a low pressure fluid reservoir; A hydraulic system comprising: the controller according to claim 1 .

Images