A compact hydraulic electronically variable displacement pump and related systems and methods

Abstract

A piston-based pump machine can include a reciprocating driver; at least one piston arranged at least partially in a respective at least one cylinder that is arranged relative to the reciprocating driver for selective engagement with the at least one piston; and a controller configured, in operation, to electronically modulate a time-varying magnetic field for the at least one cylinder such that interaction between the reciprocating driver and the at least one piston caused by the time-varying magnetic field causes selective engagement, disengagement, or modulation of displacement of each piston relative to the at least one cylinder. Related systems and methods are also disclosed.

Description

A COMPACT HYDRAULIC ELECTRONICALLY VARIABLE DISPLACEMENTPUMP AND RELATED SYSTEMS AND METHODSPRIORITY CLAIM

[0001] This application claims the benefit of U.S. Provisional Patent Application No. 63 / 669,254 filed on July 10, 2024, the entire contents of which is incorporated herein by reference.TECHNICAL FIELD

[0002] This application is directed generally to pumps and more particularly to piston-based pump machines in which the relationship between one or more pistons and a reciprocating driving member is controlled electromagnetically.BACKGROUND

[0003] Load cases for many robotic actuators require them to operate across a wide range of speeds and torques. This represents a challenge in design for efficiency in that it is difficult to identify practical solutions that operate at maximum efficiency across a wide range. Historically, robotic actuators have been operating in mostly static applications, where power supply is not an issue and onboard energy storage is not required, or in large fossil fuel powered systems, where the energy density of the fuel supply is able to supply competitive uptime between refueling regardless of actuator inefficiency. As power costs due to inefficiency pale in comparison to economic value creation for this type of application, there has been only marginal demand for technological improvements in this area to date.

[0004] Thanks to ongoing advancements in artificial intelligence, the market for compact autonomous robots is on the rise. These systems need to be able to operate on battery and maximal uptime between charges is in high demand. This shift in focus is leading to growing market demand for efficient actuator solutions. In the case of mobile robots, a potential application for this invention, two actuation types have been predominant, electromechanical and hydraulic.

[0005] Electromechanical actuators for mobile robotics applications typically consist of an electric motor coupled with a fixed ratio transmission. This solution is advantageous in that it enables appropriately compact packaging of the actuator system. However, a fixed gear ratio cannot possibly enable efficient operation across the desired load range.

[0006] Hydraulic actuation systems are power dense, capable of matching torque and speed demands at the cost of efficiency. The power on demand is made available by pumping pressurized fluid to a high pressure accumulator, whose storage pressure and volume are designed to match the torque / speed requirements of the actuator. The inefficiency comes from the fact that the fluid is throttled from the high pressure accumulator to satisfy the varying pressure / flow requirements of the actuator.

[0007] Conventional methods for operating fluid working machines more efficiently across a wide operating speed range are known. One approach includes electromagnetically controlled valves, which allow working chambers in a multi -piston machine to be selectively activated on a revolution by revolution basis to vary the pump’s time averaged output. Another explores the possibility of connecting the working chambers of such a machine directly to a load. This architecture eliminates the need for an accumulator and throttling valves, with substantial efficiency improvements and possibly a reduced footprint.

[0008] While these and other approaches may include promising approaches to the inefficiency of conventional hydraulic actuation, these architectures use solenoid actuated valves. The space requirements of solenoid valves limits the size to which these machines can be reduced and consequently their use in compact mobile robotic applications.SUMMARY

[0009] A need exists, therefore, for systems and methods for improved piston-based pump machines, systems, and methods.

[0010] In one embodiment, a piston-based pump machine comprises a reciprocating driver; at least one piston arranged at least partially in a respective at least one cylinder that is arranged relative to the reciprocating driver for selective engagement with the at least one piston; and a controller configured, in operation, to electronically modulate a time-varying magnetic field for the at least one cylinder such that interaction between the reciprocating driver and the at least one piston caused by the time-varying magnetic field causes selective engagement,disengagement, or modulation of displacement of each piston relative to the at least one cylinder.

[0011] In operation, the selective engagement, disengagement, or modulation of displacement of the at least one piston results, in operation, in variable pumping or throttling of the pistonbased pump machine.

[0012] In some embodiments, the piston-based pump machine further comprises at least one solenoid arranged relative to the at least one cylinder to, in operation and as controlled by the controller, generate the time-varying magnetic field.

[0013] In some embodiments, a portion of the at least one piston comprises a ferromagnetic material.

[0014] In some embodiments, the piston-based pump machine further comprises at least one return force means for forcing the at least one piston towards the reciprocating driver. The at least one return force means can be a biasing element or an accumulator.

[0015] In some embodiments, and in operation and as controlled by controller, the at least one solenoid generates the time-varying magnetic field to maintain the selective engagement or modulation of displacement of the at least one piston relative to the at least one cylinder.

[0016] In some embodiments, and in operation, the reciprocating member can position the at least one piston relative to the cylinder such that the time-varying magnetic field is sufficient to maintain the selective engagement or modulation of displacement of the at least one piston relative to the at least one cylinder.

[0017] In some embodiments, at least one cylinder can comprise a plurality of cylinders and the at least one piston can comprise a corresponding plurality of pistons each arranged at least partially in a respective one of the plurality of cylinders. In some embodiments, each of the plurality of cylinders is arranged radially relative to the reciprocating driver, and each of plurality of pistons is connected to the reciprocating driver by a spring or a fluid pressure.

[0018] In some embodiments, the at least one cylinder can comprise a plurality of cylinders and the at least one piston can comprise a corresponding plurality of pistons each arranged at least partially in a respective one of the plurality of cylinders. The plurality of cylinders can be arranged axially relative to the reciprocating driver, and each of plurality of pistons can be connected to the reciprocating driver by a biasing element or a fluid pressure.

[0019] In some embodiments, the at least one piston can comprise a first portion and a second portion, with the first portion arranged at least partially within the at least one cylinder and the second portion being displaceable relative to both the at least one cylinder and the first portion. The first portion and the second portion can function to form a valve within the at least one piston.

[0020] In one embodiment, a method of controlling a piston-based pump machine of this disclosure can comprise causing generation of the time-varying magnetic field to cause the selective engagement or modulation of displacement of the at least one piston relative to the at least one cylinder.

[0021] In one embodiment, a system can comprise a plurality of the piston-based pump machines of this disclosure.

[0022] In an embodiment, a piston-based pump machine can comprise driving means; at least one piston means arranged at least partially in a respective at least one cylinder that is arranged relative to the driving means for selective engagement with the at least one piston means; and control means for electronically modulating a time-varying magnetic field such that interaction between the driving means and the at least one piston means caused by the time-varying magnetic field causes selective engagement, disengagement, or modulation of displacement of each piston means relative to the at least one cylinder.

[0023] The above summary is not intended to describe each illustrated embodiment or every implementation of the subject matter hereof. The figures and the detailed description that follow more particularly exemplify various embodiments.BRIEF DESCRIPTION OF THE DRAWINGS

[0024] This disclosure may be more completely understood in consideration of the following description of various embodiments in connection with the accompanying figures, in which:

[0025] FIG. 1A is a cross-sectional view of a piston-based hydraulic pump system according to an embodiment of this disclosure.

[0026] FIG. IB is a cross-sectional view of two operational states of a first piston and a reciprocating driver of the system of FIG. 1A according to an embodiment of this disclosure.

[0027] FIG. 1C is a cross-sectional view of FIG. IB in which the solenoid is active according to an embodiment of this disclosure.

[0028] FIG. ID is a cross-sectional view of two operational states of a second piston and the reciprocating driver of the system of FIG. 1A according to an embodiment of this disclosure.

[0029] FIG. IE is a cross-sectional view of FIG. ID in which the solenoid is active according to an embodiment of this disclosure.

[0030] FIG. 2A is a cross-sectional view of two operational states of another piston and reciprocating driver according to an embodiment of this disclosure.

[0031] FIG. 2B is a cross-sectional view of FIG. 2A in which the solenoid is active according to an embodiment of this disclosure.

[0032] FIG. 3A is a cross-sectional view of two operational states of yet another piston and reciprocating driver according to an embodiment of this disclosure.

[0033] FIG. 3B is a cross-sectional view of FIG. 3 A in which the solenoid is active according to an embodiment of this disclosure.

[0034] FIG. 4A is a cross-sectional view of two operational states of still another piston and reciprocating driver according to an embodiment of this disclosure.

[0035] FIG. 4B is a cross-sectional view of FIG. 4A in which the solenoid is active according to an embodiment of this disclosure.

[0036] FIG. 5A is a cross-sectional view of two operational states of a further piston and reciprocating driver according to an embodiment of this disclosure.

[0037] FIG. 5B is a cross-sectional view of FIG. 5 A in which the solenoid is active according to an embodiment of this disclosure.

[0038] FIG. 6 is a cross-sectional view of a piston-based hydraulic pump machine according to an embodiment.

[0039] FIG. 7 is a cross-sectional view of another piston-based hydraulic pump machine according to an embodiment.

[0040] FIG. 8 is a cross-sectional view of yet another piston-based hydraulic pump machine according to an embodiment.

[0041] While various embodiments are amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit thedisclosure or claims to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the subject matter as defined by the claims.DETAILED DESCRIPTION OF EMBODIMENTS

[0042] While the disclosed technology may have embodiment in many different forms, there is shown in the drawings and will herein be described in detail several specific embodiments with the understanding that the present disclosure is to be considered as an exemplification of the principles of the technology and is not intended to limit the technology to the embodiments illustrated. The terminology used herein is for the purpose of describing particular embodiments and is not intended to limit the technology.

[0043] Throughout this disclosure, similar reference numerals are used to refer to the same or similar (though not necessarily identical) elements or components, with the leading number generally corresponding to the drawing number, unless otherwise stated. For example, an element 102 in, e.g., FIG. 1, an element 202 in FIG. 2, element 302 in FIG. 3, etc., generally will refer to the same type of element, even if the particular configuration of element 102 as compared with, e.g., element 202 varies somewhat. Additionally, the term “or” is used inclusively such that if A is or comprises B or C, A could be or comprise just B, just C, or both B and C, unless otherwise stated.

[0044] Substantial inefficiency is caused in compact actuators either by fixed gear ratio speed reducers in electromechanical systems, or by fluid throttling losses in hydraulic systems. The present disclosure is related to various embodiments of systems and control methods that combine electromagnetically controlled pistons of a hydraulic multi-piston pump in a compact infinitely variable transmission for efficient actuation.

[0045] Embodiments of this disclosure seek to address the efficiency issue of compact mobile actuators. Accordingly, disclosed herein is a variable displacement piston-based fluid-working machine, or a pump, in which control of the displacement is achieved electromagnetically. In particular, electromagnetic control is used to selectively connect and disconnecting one or more pistons, or elements or portions of the one or more pistons, from a reciprocating driving member.

[0046] In operation, one or more chambers of the piston-based pump machine, which are controlled electromagnetically, work to control flow or pressure to individual loads. In anembodiment comprising two cylinders, each with a respective piston, the machine is configured such that one cylinder chamber is fluid-driving and one cylinder chamber is fluid-throttling.

[0047] This configuration enables space efficient packaging and eliminates the need for bulky active valving, making it particularly well suited in situations in which compactness is desired, required, or otherwise advantageous. Direct connection to the actuator load eliminates the need for a high pressure accumulator and throttling valves, providing both space and efficiency gains. While some embodiments can have particular reference to non-compressible fluids but its use with gasses is not ruled out.

[0048] In many existing systems employing active valving for digital displacement or variable displacement control, actuation relies on solenoids pulling a valve element across an air gap approximately equal to the valve travel. This air gap is fundamental to valve-based architectures, imposing significant design and operational penalties. Specifically, the solenoid must generate sufficient magnetic force over the full air gap distance while overcoming a return spring or pressure force. This requires larger solenoids capable of sustaining high currents, which not only increases energy consumption but also prolongs coil rise times due to higher inductance. These rise time constraints severely limit the practical switching speed of active valve systems, often resulting in an inability to achieve reliable commutation at rotational speeds above approximately 4000 rpm.

[0049] The present disclosure attempts to overcome these and other limitations through the use of an active piston architecture in which the reciprocating driving member itself closes the air gap as part of its inherent motion cycle. At each revolution, the piston is brought into direct proximity with the driver, effectively eliminating the air gap at the point of latching or actuation. As a result, the solenoid only needs to maintain the piston in position once the air gap is closed, rather than actively pulling it across the gap. This dramatically reduces the required actuation force and current, permitting the use of smaller, lower-power coils with faster response times. These two effects are complementary: the lower energy requirement enables faster rise times, which in turn permits higher-speed operation. Practical testing of working examples has demonstrated that this architecture supports speeds exceeding 6000 rpm, with performance limitations at those speeds shifting from valve timing response to purely fluid dynamic effects such as pressure drop.

[0050] Importantly, in some embodiments, the active piston itself may include an integral valve portion — i.e., the piston is constructed in two or more parts such that one section functions both as the piston face (for generating pressure and flow) and as the moveable valve element controlling fluid communication. In these configurations, the so-called “valve” is not a separate valve in the conventional sense, but a built-in functional section of the piston assembly. Control of commutation is thus achieved by electromagnetically latching or modulating the position of this integral piston section relative to the driving member. Accordingly, these embodiments remain fully consistent with an active piston architecture, rather than representing a separate active valve system. This integrated design retains a key advantage of air gap elimination by using the reciprocating driver’s motion to close the air gap each cycle, ensuring the same benefits of lower actuation energy, faster coil rise time, and higher speed capability.

[0051] Higher achievable operating speeds enable the design of more compact systems. For example, increasing operating speed from 4000 rpm to 6000 rpm can represent a 50% increase in pump throughput for a given cylinder displacement. This allows designers to reduce the physical size of the pump for the same flow capacity.

[0052] Furthermore, conventional systems employing active valves are known to suffer from vibration issues. For a given time-averaged flow requirement, the lower maximum rpm achievable in such designs results in a lower pulsation frequency and higher transient flow variations. By enabling higher speeds with the active piston configuration, the pulsation frequency of flow is increased, which reduces the magnitude of transient flow variations required to deliver the same average flow. This higher-frequency, lower-amplitude pulsation can lead to smoother operation, reduced vibration, and improved suitability for compact and mobile robotic applications.

[0053] While certain embodiments achieve reduced or eliminated air gaps through reciprocating motion of the driving member that inherently closes the gap at actuation time, alternative configurations are also contemplated. These may include concentric sliding components, rotational engagement surfaces, telescoping structures, or other relative motion strategies that bring the actuator and latching surfaces into proximity prior to or during actuation. Such designs can similarly reduce required actuation energy and improve response times.

[0054] This disclosure also includes various methods of operating or controlling a piston-based pump machine as well as methods of operating or controlling one or more individual cylinders or pistons of a piston-based pump machine.

[0055] Turning to the drawings, FIG. 1A illustrates an exemplary piston-based pump system 100 in cross-section. Pump system 100 comprises a reciprocating driver 110. In some embodiments, reciprocating driver 110 can comprise a swashplate, wobble plate, or similar style driver. In other embodiments, a crankshaft, cam-based mechanism (including a barrel cam, axial cam, and end cam, as examples), Scotch yoke linkage, eccentric drive, oscillating or rotating cylinder block, in-line cam lob shaft, or some other rotary -to-reciprocating or other drive configuration suitable for actuating one or more hydraulic pistons can be used as or with reciprocating driver 110. Though reciprocating driver 110 is depicted and discussed in at least the example embodiment of FIGS. 1 A-5B, and other example drivers or driving means may be depicted or described with respect to other examples herein, these are not limiting with respect to the claims or other contemplated embodiments, which can utilize, work with, or comprise any suitable type of driver, driving mechanism, or driving means.

[0056] Pump system 100 also comprises two cylinders 120 and 121 in the embodiment of FIG. 1, though other embodiments can comprise more or fewer cylinders. For example, one embodiment comprises a single cylinder, and other embodiments can comprise three or more cylinders, such as four cylinders, six cylinders, eight cylinders, or more cylinders. Though some applications particular applications can benefit from embodiments that comprise an even number of cylinders, with pairs of these cylinders operating antagonistically as will be described in some examples herein, other embodiments with an odd number of cylinders are possible. The number of cylinders depicted or used in any examples herein is not limiting with respect to what may be claimed or used in any particular application.

[0057] Cylinders 120, 121 can comprise a ferromagnetic material in various embodiments. In one particular embodiment, cylinders 120 and 121 comprise ferromagnetic steel. Other embodiments can comprise some other ferromagnetic material(s) or nonmagnetic material(s), such as stainless steel, with the examples given herein being merely illustrative.

[0058] In some embodiments, pump system 100 comprises a solenoid coil associated with each cylinder. Thus, pump system 100 as depicted in FIG. 1 A comprises two solenoid coils 130 and 131 arranged relative to cylinders 120 and 121, respectively.

[0059] Each cylinder 120, 121 comprises a piston 140 and 141, respectively, arranged at least partially therein. Each piston 140, 141 generally comprises a first (e.g., head) portion and a second (e.g., base) portion. Thus, in the embodiment of FIG. 1, piston 140 comprises first portion 142 and second portion 144, and piston 141 comprises a first portion 143 and a second portion 145.

[0060] In some embodiments, each first portion 142, 143 is ferromagnetic and each second portion 144, 145 is non-magnetic. In one particular embodiment, first portions 142, 143 comprise ferromagnetic steel, and second portions 144, 145 comprise non-magnetic steel. As previously mentioned, other embodiments can comprise some other ferromagnetic material(s) or nonmagnetic material(s), such as stainless steel or even lighter-weight materials such as plastics or composites, with the examples given herein being merely illustrative.

[0061] System 100 also includes a passive inlet check valve 150 and a passive outlet check valve 151. Check valve 150 connects chamber 122 of cylinder 120 to a low pressure accumulator 160 through channel 170. Check valve 151 connects chamber 122 to load 180 through channel 173.

[0062] Chamber 123 of cylinder 121 is connected to load 180 through channels 171 and 173 and to low pressure accumulator 160 through channel 172. Other components not explicitly depicted or described also are or can be included in system 100, such as a power source.

[0063] A controller 190 controls the state of coils 130 and 131 (represented by dashed lines in FIG. 1A) and monitors various operational characteristics of pump system 100. These characteristics can include a speed of reciprocating driver 110 (through an encoder 191, which interacts with reciprocating member 110 to determine a current position or speed of reciprocating member 110, as is generally known to those having skill in the art), a pressure of load 180 (through a pressure transducer 192), and a fluid flow rate in channel 173 (through flow meter 193).

[0064] In operation, piston 140 pumps fluid from accumulator 160 to load 180. Piston 141 acts as a throttling valve by throttling fluid from load 180 to low pressure accumulator 160. In an open position as is generally depicted in FIG. 1, piston 141 sits against or relative to valve seat 152. Low pressure accumulator 160 can be maintained at a boost pressure to prevent cavitation effects in pump system 100.

[0065] FIG. IB illustrates two operational states of piston 140 when solenoid 130 is inactive, separated by a dashed line, according to an embodiment. On the left side, piston 140 is in a bottom dead center position (BDC), having sucked fluid into chamber 122 through check valve 150. The return of piston 140 to BDC, following the motion of reciprocating driver 110, is enabled in some embodiments by a biasing element 162 or a boost pressure from accumulator 160. Biasing element 162 (as well as biasing element 163 discussed elsewhere herein) can comprise a spring or other elastic mechanical component in some embodiments, while in other embodiments biasing element 162 (as well as biasing element 163) can comprise some other component altogether.

[0066] On the right side of FIG. 1A, piston 140 is depicted at top dead center (TDC), having pumped fluid out of chamber 122 through check valve 150.

[0067] FIG. 1C illustrates two operational of piston 140 when solenoid 130 is active according to an embodiment. On the left side, piston 140 is latched at TDC, despite reciprocating driver 110 being at a position for BDC. Piston 140 will remain in this position so long as solenoid 130 is active (for example, with a 100% duty cycle, which deactivates the pumping function). Solenoid 130 is configured such that activation with a 100% duty cycle will result in a force on piston 140 equal or greater in magnitude and opposite in direction to the return force provided by biasing element 162 or the boost pressure of accumulator 160.

[0068] Solenoid 130 can be activated at duty cycles below 100% in some embodiments. This will allow piston 140 to travel from TDC towards BDC, though at a reduced speed compared to reciprocating driver 110. Under these circumstances, reciprocating driver 110 will eventually re-engage piston 140 somewhere between TDC and BDC and result in a pump stroke in which only a fraction of the total swept volume of piston 140 is pumped.

[0069] FIG. ID illustrates two operational states of piston 141 when solenoid 131 is inactive according to an embodiment. On the left, piston 141 is at BDC, enabling flow of fluid through chamber 123 between channels 171 and 172. The return of piston 141 to BDC, following the motion of reciprocating driver 110, is enabled by a biasing element 163 or the pressure of chamber 123.

[0070] On the right side of FIG. ID, piston 141 is at TDC. In this position second portion 143 of piston 141 is close to but not engaging valve seat 152, hence still enabling fluid flow, though at a reduced rate as the proximity of second portion 145 to valve seat 152 will restrict the flow.

[0071] FIG. IE illustrates two operational states of piston 141 when solenoid 131 is active according to an embodiment. On the left side, piston 141 is latched past TDC, engaging valve seat 152 despite reciprocating driver 110 being at BDC. Piston 141 will remain in this position so long as solenoid 131 is active (e.g., with a 100% duty cycle), deactivating the throttling function of piston 141. Solenoid 131 is designed such that activating it with a 100% duty cycle will result in a force greater in magnitude and opposite in direction to the return force provided by biasing element 163 or the pressure of chamber 123.

[0072] Solenoid 131, like solenoid 130, can be activated at duty cycles below 100% in some embodiments. This will allow piston 141 to travel from TDC towards BDC, though at a reduced speed compared to reciprocating driver 110. Under these circumstances, reciprocating driver 110 will eventually re-engage piston 141 somewhere between TDC and BDC. This reduced motion of piston 141 will result in a lower time averaged flow area between channels 171 and 172, causing a reduction in flow compared to the case described with respect to FIG. IB and 1C.

[0073] The inlet and outlet channels (e.g., channels 170, 171, 172, 173) do not need to be arranged as depicted, with the figures showing just one example embodiment. In some embodiments it could be beneficial to have both channels perpendicular to the piston axis, as is the case for channel 171 in FIGS. 1 A-1E. In this case there would not be a valve seat as such for piston 141, but piston 141 would rather act as a spool valve for controlling flow. It is also worth noting that one or more of the channels can be shaped so that the flow therethrough is in some way dictated by the position of the piston. Consider a simplified example in which there are two openings arranged one on top of the other. As the piston travels it would first cover both, then one, then none, with consequent increase in flow. This can be achieved by using multiple channels or by adjusting a geometry of the channel, in various embodiments.

[0074] Referring again to FIG. 1A, cylinder 120 is responsible for pumping fluid to load 180. By controlling solenoid 130 at each revolution of reciprocating driver 110, cylinder 120 can be set to one of three modes:• With solenoid 130 deactivated, cylinder 120 will pump the full swept volume of piston 140.• With solenoid 130 at 100% duty cycle, cylinder 120 will idle and not pump any fluid.• With solenoid 130 between 0% and 100% duty cycle, cylinder 120 will pump only a fraction of the total swept volume proportional to the duty cycle.

[0075] Cylinder 121 is responsible for throttling fluid through chamber 123 between channels 171 and 172. By controlling solenoid 130 at each revolution of reciprocating driver 110, cylinder 121 can be set to one of three modes:• With solenoid 131 deactivated, cylinder 121 will enable maximum flow.• With solenoid 131 at 100% duty cycle, cylinder 121 will function as a closed valve.• With solenoid 131 between 0% and 100% duty cycle, cylinder 121 will restrict flow proportionally to the duty cycle.

[0076] Controller 190 can be configured to operate machine 100 in at least three modes:• An open -loop stepper mode, in which the pumping function of cylinder 120 alternates between full pump and idle cycles and the throttling function of cylinder 121 is set to no flow mode.• A closed-loop servo control mode, in which the signal from flow meter 193 feeds back to the controller to determine flow rate to the load, though this may be measured by other means depending on the final configuration, and pump and throttle functions of each cylinder are set accordingly between 0 and 100% at each revolution.• A closed loop force control mode, in which the pressure from pressure transducer 192 provides feedback and pump and throttle functions of each cylinder 120, 121 are set accordingly between 0 and 100% at each revolution.

[0077] The configuration depicted in FIGS. 1A-1E makes use of two of many possible piston / cylinder configurations and an example of how these can be arranged in just one of many multi-piston machine embodiments.

[0078] With regards to piston / cylinder configurations, the types introduced above can be classified as “normally active” pistons. Different configurations can be better suited to certain types of applications or machine configurations. For example, unlike the configurations shown in FIGS. 1B-1E, the configuration depicted next in FIGS. 2A and 2B is such that the piston can be made entirely of magnetic steel, as the piston is latched in its TDC position. Latching at TDC can provide a stronger magnetic latching force compared to the side latch of the embodiments above. One advantage of this configuration might be that the solenoid coils can require less power to induce higher latching forces, though a potential disadvantage might be that surface level phenomena such as eddy currents on the faces of the two latching surfaces might induce delays in the collapse of the latching force with consequences on controllabilityat higher drive speeds. Such disadvantages can be overcome or tolerated in some embodiments and applications, however.

[0079] FIG. 2A illustrates an alternative embodiment of the normally active type, when solenoid 230 is inactive. On the left side, piston 240 is in BDC, having sucked fluid into chamber 222 through inlet check valve 250a. The return of piston 240 to BDC, following the motion of reciprocating driver 210, is enabled in some embodiments by a biasing element 262 or by system boost pressure, where available based on machine configuration.

[0080] On the right side of FIG. 2A, piston 240 is depicted at TDC, having pumped fluid out of chamber 222 through outlet check valve 250b.

[0081] FIG. 2B illustrates an two operational states of piston 240 when solenoid 230 is active according to an embodiment. On the left side, piston 230 is latched at TDC, despite reciprocating driver 210 being at a position for BDC. Piston 230 will remain in this position so long as solenoid 230 is active (for example, with a 100% duty cycle, which deactivates the pumping function). Solenoid 230 is configured such that activation with a 100% duty cycle will result in a force on piston 240 equal or greater in magnitude and opposite in direction to the return force provided by biasing element 262 or the system boost pressure.

[0082] Solenoid 230 can be activated at duty cycles below 100% in some embodiments. This will allow piston 240 to travel from TDC towards BDC, though with delayed timing compared to reciprocating driver 210. Under these circumstances, reciprocating driver 210 will eventually re-engage piston 240 somewhere between TDC and BDC and result in a pump stroke in which only a fraction of the total swept volume of piston 240 is pumped.

[0083] FIG. 3A illustrates two operational states of yet another alternative piston / cylinder embodiment of the normally active type when solenoid 330 is inactive according to an embodiment. In this particular configuration, low pressure inlet valve 353 is housed in piston 340. This requires a flooded crank-case to enable low pressure fluid to flow into chamber 322 through piston 340. On the left side, piston 340 is in a BDC, having sucked fluid into chamber 322 through check valve 350. The return of piston 340 to BDC, following the motion of reciprocating driver 310, is enabled by a biasing element 362.

[0084] On the right side of FIG. 3 A, piston 340 is depicted at TDC, having pumped fluid out of chamber 322 through check valve 350.

[0085] FIG. 3B illustrates two operational states of piston 340 when solenoid 330 is active according to an embodiment. On the left side, piston 340 is latched at TDC, despite reciprocating driver 310 being at a position for BDC. Piston 340 will remain in this position so long as solenoid 330 is active (for example, with a 100% duty cycle, which deactivates the pumping function). Solenoid 330 is configured such that activation with a 100% duty cycle will result in a force on piston 340 equal or greater in magnitude and opposite in direction to the return force provided by biasing element 362.

[0086] Solenoid 330 can be activated at duty cycles below 100% in some embodiments. This will allow piston 340 to travel from TDC towards BDC, though with delayed timing compared to reciprocating driver 310. Under these circumstances, reciprocating driver 310 will eventually re-engage piston 340 somewhere between TDC and BDC and result in a pump stroke in which only a fraction of the total swept volume of piston 340 is pumped.

[0087] While certain embodiments integrate the valving or other flow-control element(s) or mechanism directly within the piston body itself (such as in FIGS. 3A and 3B), other configurations are contemplated in which the flow-control element(s) or mechanism is or are physically separable but still mechanically coupled to the piston. For example, motion of the reciprocating driver may inherently reduce the actuation gap or synchronize movement of a separate valve component, achieving similar advantages in reduced actuation force and faster response times. Such “hybrid” arrangements allow design flexibility while retaining the core benefits of the disclosed commutation principles. An example embodiment of such a configuration, in which the piston is still an active piston and comprises an upper piston portion that is also a valve, is described with reference to FIGS. 4A and 4B.

[0088] FIG. 4A illustrates two operational states of yet another alternative piston / cylinder embodiment of the normally active type, in which solenoid 430 is inactive according to an embodiment. In this particular configuration, a low pressure inlet valve is housed in piston 440, in that piston 440 itself comprises two portions that together form such a valve. This requires a flooded crank-case to enable low pressure fluid to flow into chamber 422 through piston 440.

[0089] In this embodiment piston 440 comprises two sections, a first piston section 440a that is both the face of piston 440 (and consequently responsible of the pumping of the fluid) and a valve, and a second piston section 440b responsible for commutation. On the left side, piston 440 is in BDC position, having sucked fluid into chamber 422 through first piston section 440a.The return of piston 440 to BDC, following the motion of reciprocating driver 410, is enabled by a biasing element 462.

[0090] On the right side of FIG. 4A, piston 440 is depicted at TDC, having pumped fluid out of chamber 422 through check valve 450.

[0091] FIG. 4B depicts two operational states of piston 440 when solenoid 430 is active according to an embodiment. On the left side, first piston section 440a is latched at TDC, despite reciprocating driver 410 and second piston section 440b being at a position for BDC, where first piston portion 440a and second piston portion 440b are coupled through a tension spring 464. First piston portion 44a will remain in this position so long as solenoid 430 is active (for example, with a 100% duty cycle, which deactivates the pumping function). Solenoid 430 is configured such that activation with a 100% duty cycle will result in a force on first piston portion 440a equal or greater in magnitude and opposite in direction to the return force provided by spring 464.

[0092] Solenoid 430 can be activated at duty cycles below 100% in some embodiments. This will allow first piston portion 440a to travel from TDC towards BDC, though with delayed timing compared to second piston portion 440b, which follows reciprocating driver 410 due to the force exerted by spring 464. Under these circumstances, second piston portion 440b will eventually re-engage first piston portion 440a somewhere between TDC and BDC and result in a pump stroke in which only a fraction of the total swept volume of piston 440 is pumped.

[0093] With regards to contemplated piston / cylinder configurations, some embodiments can be considered to be “normally inactive” pistons, in contrast with those discussed and depicted thus far.

[0094] FIG. 5A illustrates two operational states of a normally inactive piston / cylinder embodiment, in which solenoid 530 is inactive according to an embodiment. In this embodiment, low pressure inlet valve 553 is arranged in first piston portion 540a. This requires a flooded crank-case to enable low pressure fluid to flow into chamber 522 (see FIG. 5B) through first piston portion 540a and second piston portion 540b.

[0095] On the left side, second piston portion 540b is in a BDC position, while first piston portion 540a is maintained at TDC through the action of spring 564.

[0096] On the right side of FIG. 5A, first piston portion 540a is (still) depicted at TDC. No movement by first piston portion 540a results in no fluid flow.

[0097] FIG. 5B depicts two operational positions of piston 540 when solenoid 530 is active according to an embodiment. On the left side, first piston portion 540a is latched to second piston portion 540b, overcoming the force from spring 564. Second piston portion 540b will remain latched to first piston portion 540a so long as solenoid 530 is active (for example, with a 100% duty cycle, which fully activates the pumping function). Solenoid 530 is configured such that activation with a 100% duty cycle will result in a force on piston 540 equal or greater in magnitude and opposite in direction to the return force provided by spring 564.

[0098] Solenoid 530 can be activated at duty cycles below 100% in some embodiments. This will allow first piston portion 540a to travel from TDC towards BDC only so long as the magnetic force overcomes the force from spring 564. Under these circumstances, second piston portion 540b will eventually re-engage first piston portion 540a somewhere between TDC and BDC and result in a pump stroke in which only a fraction of the total swept volume of piston 540 is pumped.Control Methodologies

[0099] As previously mentioned, embodiments of systems disclosed herein can comprise a controller, such as controller 190 in system 100 of FIG. 1A. Various control methodologies can be implemented by or with such a controller, and still other embodiments can comprise alternate or additional controller or control means.

[0100] Generally speaking, commutation of individual cylinders in embodiments of the various systems disclosed herein can be achieved through a variety of control methodologies, tailored to the desired level of precision, responsiveness, and system complexity.• Continuous Holding Current Control: In one embodiment, the electromagnetic latch is supplied with a continuous holding current, which defines the force resisting movement of an internal piston section. This current can be set to achieve a desired displacement setpoint and can be adjusted as needed over time in response to higher- level control commands (e.g., changing flow demand), but remains constant within each reciprocation cycle. The timing at which the internal piston section moves relative to the driving member is passively determined by the mechanical balance between the steady electromagnetic holding force and a biasing element such as a spring.Once set, this approach passively defines the effective stroke length for each cycle in a repeatable manner, with no requirement for active, per-cycle electronic actuation or phase-synchronous control. This methodology simplifies the control architecture and reduces energy consumption while avoiding electronically commutated valve actuation synchronized to the reciprocation phase.• Cycle-by-Cycle Open-Loop Control: In another embodiment, the controller applies a continuous voltage to the coil on a revolution-by-revolution basis, with timing coordinated to the shaft position. For example, open-loop stepper-like control can be used where known crankshaft position enables on / off coil control at the correct phase. This method supports variable displacement modes by electronically selecting the release timing on a per-cycle basis.• Synchronized PWM Control with Position Feedback: In yet another embodiment, the controller generates pulse-width modulated signals synchronized to the position of the reciprocating driving member. On a revolution-by-revolution basis, each pulse can be initiated at a desired crank angle, with the modulation depth determining effective actuation duration. This strategy enables precise cycle-synchronous control of commutation events, supporting real-time adjustment of displacement volume for each working chamber in response to system demands.• Variable Stroke Control: In some embodiments, the relative position of the moveable piston component may be controlled to achieve not only discrete (e.g., on / off or stepped) displacement settings but also continuously variable stroke lengths. This can be accomplished by modulating the latching or holding force in real time, allowing fine-grained adjustment of effective displacement volume on a continuum. Such continuous control may be advantageous for applications requiring precise flow modulation, smooth actuator motion, or adaptive control in response to varying load conditions.• Control Signal Variations: The actuation and latching force in these systems can be controlled using various electrical signals, including but not limited to current, voltage, duty-cycle modulation, or other forms of electrical parameter adjustment. Control can be implemented in open-loop or closed-loop configurations depending on system requirements, supporting a range of complexity from simple setpoint-based operation to sophisticated sensor-driven adaptive control.

[0101] FIG. 6 illustrates an exemplary piston-based hydraulic pump system 600 in crosssection. Pump system 600 comprises a reciprocating driver 610, in this embodiment a radial crankshaft configuration (though other configurations can be used in other embodiments).

[0102] Pump system 600 also comprises at least one cylinder 620 in the embodiment of FIG. 6, though other embodiments can comprise more cylinders. Cylinder 620- can be configured according to, though not limited by, any of the above-described piston / cylinder configurations.

[0103] In some embodiments, pump system 600 comprises a solenoid coil associated with each cylinder. Thus, pump system 600 as depicted comprises one solenoid coil 630 arranged around cylinder 620.

[0104] Cylinder 620 is arranged relative to a passive inlet check valve, in this case integrated in a piston 640 as per some embodiments above, a passive outlet check valve 651 and a flooded crankcase 611. Alternative embodiments in which the inlet check valve is built into the body of the pump and draws fluid from either a flooded crankcase or a dedicated reservoir are also possible, as will be apparent to those skilled in the art. The piston-integrated check valve connects flooded crankcase 611 to chamber 620. Check valve 651 connects chamber 622 to load 680 through channel 670.

[0105] In this configuration, load 680 represents a hydraulic motor. While the low pressure hydraulic circuit can be configured in a variety of ways as obvious to those skilled in the art, in this embodiment a low pressure outlet of load 680 is shown to be connected to a boost pressure accumulator 660 and to flooded crankcase 611 through filter 682. Thus, in operation, piston 640 pumps fluid from flooded crankcase 611 to load 680 .

[0106] A controller 690 controls the state of coil 630, and consequent pump commutation, and monitors various elements and operational characteristics of pump system 600. These characteristics can include a speed of reciprocating driver 61 ©(through an encoder 691, which interacts with reciprocating driver 610 to determine a current position of reciprocating driver 610, as is generally known to those having skill in the art), a pressure of load 680 (through a pressure transducer 692), a pressure of boost pressure accumulator 660 and speed of load 680 (through an encoder 693, which interacts with the output shaft of load 680 to determine a current position or speed of load output shaft, as is generally known to those having skill in the art). These are examples of only some of the elements and characteristics that can be monitored and measured in hydraulic pump systems, and other sensors (e.g., transducers, encoders, etc.)to measure various other characteristics can be included in other embodiments, as will be appreciated by those skilled in the art.

[0107] FIG. 7 illustrates another exemplary piston-based hydraulic pump system 700 in crosssection. Pump system 700 comprises a reciprocating driver 710, in this embodiment a radial crankshaft configuration. Pump system 700 also comprises at least one cylinder 720 in the embodiment of FIG. 7, though other embodiments can comprise more cylinders. Cylinder 720 can be configured according to, though not limited by, any of the above-described piton / cylinder configurations

[0108] In some embodiments, pump system 700 comprises a solenoid coil associated with each cylinder. Thus, pump system 700 as depicted comprises one solenoid coil 730 arranged around cylinder 720.

[0109] Cylinder 720 has a passive inlet check valve, in this case integrated in piston 740 as per some embodiments above, a passive outlet check valve 751, and a flooded crankcase 711. Alternative embodiments in which the inlet check valve is built into the body of the pump and draws fluid from either a flooded crankcase or a dedicated reservoir are also possible, as obvious to those skilled in the art. The piston integrated check valve connects flooded crankcase 711 to chamber 722. Check valve 751 connects chamber 722 to load 780 through channel 770.

[0110] In this configuration, load 780 can represent a linear hydraulic piston type actuator. While the low pressure hydraulic circuit can be configured in a variety of ways, as will be apparent to those skilled in the art, in this embodiment a low pressure outlet of load 780 is connected through a throttling valve 781 to a boost pressure accumulator 760 and in turn to flooded crankcase 711 through filter 782.[OHl] In operation, piston 740 pumps fluid from flooded crankcase 711 to load 780. The flow rate from the commutated pump output will result in a varying pressure at load 780 as throttling valve 781 restricts flow to the downstream low-pressure side circuit.

[0009] A controller 790 controls the state of coil 730, and consequent pump commutation, and monitors various elements and operational characteristics of pump system 700. These characteristics can include a speed of reciprocating driver 710 (through an encoder 791, which interacts with reciprocating member 710 to determine a current position of reciprocating member 710, as is generally known to those having skill in the art), a pressure of load 780(through a pressure transducer 792), a pressure of boost pressure accumulator 760 and speed of load 780 (through an encoder 793, which interacts with the output shaft of load 780 to determine a current position or speed of the load output shaft, as is generally known to those having skill in the art). As mentioned above, these are examples of only some of the elements and characteristics that can be monitored and measured in hydraulic pump systems, and other sensors (e.g., transducers, encoders, etc.) to measure various other characteristics can be included in other embodiments, as will be appreciated by those skilled in the art.

[0112] FIG. 8 illustrates an exemplary embodiment of a piston-based hydraulic pump system 800 in cross-section. Pump system 800 combines three of the configurations described above into a single machine, though other embodiments can comprise more cylinders and any combination of cylinder and load configurations. In this configuration, cylinders and loads are arranged such that from with a single reciprocating driving member 811 a variety of load types (880a_through 880 / / ) can be controlled independently.

[0113] A controller 890 controls the state of independent coils, and consequent commutation, and monitors various operational characteristics of pump system 800. These characteristics can include a speed of reciprocating driver 810 (through an encoder 891, which interacts with reciprocating driver 810 to determine a current position of reciprocating driver 810, as is generally known to those having skill in the art), a pressure of loads 880a, 880b, and 880 / / (through pressure transducers 892a, 892b and 892 / / , respectively), a pressure of boost pressure accumulator 860, and speed of load, similar to as described above with respect to FIG. 7.Applications and Use Cases

[0114] The active piston commutation technology described herein, including but not limited to embodiments employing electronically controlled latching mechanisms, passive valve elements, and adjustable displacement via modulated stroke length, is broadly applicable across a wide range of industrial, robotic, vehicular, and consumer applications. Examples will be included herein but are not limiting with respect to currently anticipated, as well as possible future, applications and technologies.

[0115] Embodiments and principles disclosed herein are not limited to use within centralized, multi-valve hydraulic circuits or integrated machine control systems. Rather, they can be implemented or deployed in modular, distributed, or standalone actuator units. For example, single-cylinder or multi-cylinder pumps with active piston commutation can be integrateddirectly into an actuator housing, providing local generation of hydraulic pressure tailored to the actuator's requirements. Such configurations can replace or augment traditional hydraulic systems, pneumatic cylinders, electric linear actuators, or even rotary electric motors in many contexts.

[0116] Potential use cases include, but are not limited to, the following examples:• Robotic manipulators, such as dexterous hands or multi -joint arms, in which distributed pumps with active piston control can enable compact, integrated hydraulic actuation at each joint or digit.• Soft robotics, employing local, electronically controlled hydraulic sources for precise inflation and deflation of compliant structures.• Aerial vehicles (e.g., drones), in which distributed hydraulic actuation for rotor actuation, tilting rotors, variable pitch mechanisms, or landing gear can benefit from compact, low-latency, and energy-efficient variable displacement pumping modules.• Legged robots and exoskeletons, in which local, high-force hydraulic actuation can be highly advantageous for joint control with low mass and high energy density.• Off-highway equipment (e.g., excavators, loaders, agricultural machinery), enabling variable displacement actuation for attachments or tools without reliance on complex, centralized valve banks.• Industrial machinery, including presses, forming equipment, and precision positioning systems, in which variable displacement pumping can replace electric or pneumatic actuators for improved control and efficiency.• Medical devices in which precise fluid delivery or actuation in compact form factors are advantageous or required.• Consumer products, such as powered tools, fitness equipment, or mobility devices, that can benefit from small-scale, energy-efficient, electronically tunable hydraulic actuation.Marine equipment, including steering actuators, fin controllers, and other systems in which compact, distributed hydraulic actuation improves responsiveness and packaging.• Aerospace systems, such as control surfaces, landing gear, or other actuation requirements where weight savings, reliability, and precise control are critical.• Underwater vehicles, for propulsion, manipulation, or buoyancy control using compact, pressure-tolerant hydraulic modules.• Powered prosthetic and orthotic devices, in which integrated hydraulic actuation can deliver high force density in a wearable form factor.• Wearable exosuits and construction robotics, enabling human augmentation and powered motion in compact, modular packages for industrial or field use.

[0117] These and other example implementations can benefit from the modularity, distributed control capability, and energy efficiency enabled by one or more of the embodiments, or features or elements of the embodiments, disclosed herein.

[0118] Embodiments of this disclosure support both asynchronous displacement setting (for example, using constant holding current modes without per-cycle electronic commutation) and cycle-synchronous control (where desired for higher performance or precision). As such, embodiments are adaptable to applications in which simple, robust control architectures or those requiring fine-grained, real-time actuation are advantageous or required.

[0119] It is expressly contemplated that active piston commutation systems of various embodiments of this disclosure can be used in single-cylinder configurations, multiple singlecylinder modules operating in parallel or independently, or integrated multi-cylinder pump assemblies. These can be deployed in isolated actuators, distributed networks of actuators, or conventional centralized hydraulic circuits.

[0120] Accordingly, the present disclosure is not limited to any specific industrial sector or machine type, and it is intended to encompass all applications in which fluid power actuation can be improved, miniaturized, modularized, or optimized through the use of active pistonbased displacement control with electronically adjustable latching mechanisms and / or passive valve configurations.

[0121] The following clauses form part of this disclosure:

[0122] Clause A: A piston-based pump machine comprising: a reciprocating driver; at least one piston arranged at least partially in a respective at least one cylinder that is arranged relativeto the reciprocating driver for selective engagement with the at least one piston; and a controller configured, in operation, to electronically modulate a time-varying magnetic field for the at least one cylinder such that interaction between the reciprocating driver and the at least one piston caused by the time-varying magnetic field causes selective engagement, disengagement, or modulation of displacement of each piston relative to the at least one cylinder.

[0123] Clause B: The piston-based pump machine of Clause A, wherein the selective engagement, disengagement, or modulation of displacement of the at least one piston results, in operation, in variable pumping or throttling of the piston-based pump machine.

[0124] Clause C: The piston-based pump machine of Clause A or Clause B, further comprising at least one solenoid arranged relative to the at least one cylinder to, in operation and as controlled by the controller, generate the time-varying magnetic field.

[0125] Clause D: The piston-based pump machine of any of Clauses A-C, wherein a portion of the at least one piston comprises a ferromagnetic material.

[0126] Clause E: The piston-based pump machine of any of Clauses A-D, further comprising at least one return force means for forcing the at least one piston towards the reciprocating driver.

[0127] Clause F: The piston-based pump machine of Clause E, wherein the at least one return force means is a biasing element or an accumulator.

[0128] Clause G: The piston-based pump machine of any of Clauses C-F, wherein, in operation and as controlled by controller, the at least one solenoid generates the time-varying magnetic field to maintain the selective engagement or modulation of displacement of the at least one piston relative to the at least one cylinder.

[0129] Clause H: The piston-based pump machine of Clause G, wherein, in operation, the reciprocating driver positions the at least one piston relative to the cylinder such that the timevarying magnetic field is sufficient to maintain the selective engagement or modulation of displacement of the at least one piston relative to the at least one cylinder.

[0130] Clause I: The piston-based pump machine of any of Clauses A-H, wherein: the at least one cylinder comprises a plurality of cylinders and the at least one piston comprises a corresponding plurality of pistons each arranged at least partially in a respective one of the plurality of cylinders, each of the plurality of cylinders is arranged radially relative to thereciprocating driver, and each of plurality of pistons is connected to the reciprocating driver by a spring or a fluid pressure.

[0131] Clause J: The piston-based pump machine of any of Clauses A-H, wherein: the at least one cylinder comprises a plurality of cylinders and the at least one piston comprises a corresponding plurality of pistons each arranged at least partially in a respective one of the plurality of cylinders, the plurality of cylinders are arranged axially relative to the reciprocating driver, and each of plurality of pistons is connected to the reciprocating driver by a biasing element or a fluid pressure.

[0132] Clause K: The piston-based pump machine of any of Clauses A- J, wherein the at least one piston comprises a first portion and a second portion, wherein the first portion is arranged at least partially within the at least one cylinder and the second portion is displaceable relative to both the at least one cylinder and the first portion.

[0133] Clause L: The piston-based pump machine of Clause K, wherein the first portion and the second portion function to form a valve within the at least one piston.

[0134] Clause M: A method of controlling the piston-based pump machine of any of Clauses A-L, comprising: causing generation of the time-varying magnetic field to cause the selective engagement or modulation of displacement of the at least one piston relative to the at least one cylinder.

[0135] Clause N: A system comprising a plurality of the piston-based pump machines of any of Clauses A-L.

[0136] Clause O: A piston-based pump machine comprising: driving means; at least one piston means arranged at least partially in a respective at least one cylinder that is arranged relative to the driving means for selective engagement with the at least one piston means; and control means for electronically modulating a time-varying magnetic field such that interaction between the driving means and the at least one piston means caused by the time-varying magnetic field causes selective engagement, disengagement, or modulation of displacement of each piston means relative to the at least one cylinder.

[0137] Various embodiments of systems, devices, and methods have been described herein. These embodiments are given only by way of example and are not intended to limit the scope of the claimed inventions. It should be appreciated, moreover, that the various features of the embodiments that have been described may be combined in various ways to produce numerousadditional embodiments. Moreover, while various materials, dimensions, shapes, configurations and locations, etc., have been described for use with disclosed embodiments, others besides those disclosed may be utilized without exceeding the scope of the claimed inventions.

[0138] Persons of ordinary skill in the relevant arts will recognize that the subject matter hereof may comprise fewer features than illustrated in any individual embodiment described above. The embodiments described herein are not meant to be an exhaustive presentation of the ways in which the various features of the subject matter hereof may be combined. Accordingly, the embodiments are not mutually exclusive combinations of features unless explicitly stated or described as such; rather, the various embodiments can comprise a combination of different individual features selected from different individual embodiments, as understood by persons of ordinary skill in the art. Moreover, elements described with respect to one embodiment can be implemented in other embodiments even when not described in such embodiments unless otherwise noted.

[0139] It should be understood that the individual operations used in the methods of the present teachings may be performed in any order and / or simultaneously, as long as the teaching remains operable. Furthermore, it should be understood that the apparatus and methods of the present teachings can include any number, or all, of the described embodiments, as long as the teaching remains operable.

[0140] Although a dependent claim may refer in the claims to a specific combination with one or more other claims, other embodiments can also include a combination of the dependent claim with the subject matter of any or each other dependent claim or a combination of one or more features with other dependent or independent claims. Such combinations are proposed herein unless it is stated that a specific combination is not intended. Any use of “or” is inclusive unless otherwise stated (e.g., a system comprising A or B also can comprise A and B).

[0141] Any incorporation by reference of documents above is limited such that no subject matter is incorporated that is contrary to the explicit disclosure herein. Any incorporation by reference of documents above is further limited such that no claims included in the documents are incorporated by reference herein. Any incorporation by reference of documents above is yet further limited such that any definitions provided in the documents are not incorporated by reference herein unless expressly included herein.

[0142] For purposes of interpreting the claims, it is expressly intended that the provisions of 35 U.S.C. § 112(f) are not to be invoked unless the specific terms “means for” or “step for” are recited in a claim.

Claims

CLAIMSWhat is claimed is:

1. A piston-based pump machine comprising: a reciprocating driver; at least one piston arranged at least partially in a respective at least one cylinder that is arranged relative to the reciprocating driver for selective engagement with the at least one piston; and a controller configured, in operation, to electronically modulate a time-varying magnetic field for the at least one cylinder such that interaction between the reciprocating driver and the at least one piston caused by the time-varying magnetic field causes selective engagement, disengagement, or modulation of displacement of each piston relative to the at least one cylinder.

2. The piston-based pump machine of claim 1, wherein the selective engagement, disengagement, or modulation of displacement of the at least one piston results, in operation, in variable pumping or throttling of the piston-based pump machine.

3. The piston-based pump machine of claim 1, further comprising at least one solenoid arranged relative to the at least one cylinder to, in operation and as controlled by the controller, generate the time-varying magnetic field.

4. The piston-based pump machine of claim 3, wherein a portion of the at least one piston comprises a ferromagnetic material.

5. The piston-based pump machine of claim 1, further comprising at least one return force means for forcing the at least one piston towards the reciprocating driver.

6. The piston-based pump machine of claim 5, wherein the at least one return force means is a biasing element or an accumulator.

7. The piston-based pump machine of claim 3, wherein, in operation and as controlled by controller, the at least one solenoid generates the time-varying magnetic field to maintain the selective engagement or modulation of displacement of the at least one piston relative to the at least one cylinder.

8. The piston-based pump machine of claim 7, wherein, in operation, the reciprocating driver positions the at least one piston relative to the cylinder such that the time-varying magnetic field is sufficient to maintain the selective engagement or modulation of displacement of the at least one piston relative to the at least one cylinder.

9. The piston-based pump machine of claim 1, wherein: the at least one cylinder comprises a plurality of cylinders and the at least one piston comprises a corresponding plurality of pistons each arranged at least partially in a respective one of the plurality of cylinders, each of the plurality of cylinders is arranged radially relative to the reciprocating driver, and each of plurality of pistons is connected to the reciprocating driver by a spring or a fluid pressure.

10. The piston-based pump machine of claim 1, wherein: the at least one cylinder comprises a plurality of cylinders and the at least one piston comprises a corresponding plurality of pistons each arranged at least partially in a respective one of the plurality of cylinders, the plurality of cylinders are arranged axially relative to the reciprocating driver, and each of plurality of pistons is connected to the reciprocating driver by a biasing element or a fluid pressure.

11. The piston-based pump machine of claim 1, wherein the at least one piston comprises a first portion and a second portion, wherein the first portion is arranged at least partially within the at least one cylinder and the second portion is displaceable relative to both the at least one cylinder and the first portion.

12. The piston-based pump machine of claim 11, wherein the first portion and the second portion function to form a valve within the at least one piston.

13. A method of controlling the piston-based pump machine of claim 1, comprising: causing generation of the time-varying magnetic field to cause the selective engagement or modulation of displacement of the at least one piston relative to the at least one cylinder.

14. A system comprising a plurality of the piston-based pump machines of claim 1.

15. A pi ston-based pump machine compri sing : driving means; at least one piston means arranged at least partially in a respective at least one cylinder that is arranged relative to the driving means for selective engagement with the at least one piston means; and control means for electronically modulating a time-varying magnetic field such that interaction between the driving means and the at least one piston means caused by the time-varying magnetic field causes selective engagement, disengagement, or modulation of displacement of each piston means relative to the at least one cylinder.

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