Mechanisms for creating undulating motion, such as for propulsion, and for harnessing the energy of moving fluid

[0001] This application is a Non-Provisional of and claims priority under 35 U.S.C. §119 to prior U.S. provisional patent application Ser. No. 61/431,412 entitled, “MECHANISMS FOR CREATING UNDULATING MOTION, SUCH AS PROPULSION, AND FOR HARNESSING THE ENERGY OF MOVING FLUID,” filed Jan. 10, 2011.

[0002] This application is also a Continuation-In-Part of and claims priority under 35 U.S.C. §120 to co-pending U.S. non-provisional patent application Ser. No. 12/617,618 entitled, “Pliant or Compliant Elements for Harnessing the Forces of Moving Fluid to Transport Fluid or Generate Electricity,” filed Nov. 12, 2009; which in turn claims priority under 35 U.S.C. §120 to prior non-provisional patent application Ser. No. 12/242,144 entitled, “PLIANT MECHANISMS FOR EXTRACTING POWER FROM MOVING FLUID,” filed Sep. 30, 2008, which in turn claims priority under 35 U.S.C. §120 to U.S. non-provisional patent application Ser. No. 12/150,910 entitled, “Power generator for extracting power from fluid motion,” filed May 1, 2008, which in turn claims priority under U.S.C. §119 to U.S. provisional patent application Ser. No. 60/926,984 filed May 1, 2007.

[0003] All of the aforementioned applications are expressly incorporated herein by reference.

[0004] Disclosed are apparatuses, methods and systems which, in various embodiments, facilitate the conversion of mechanical energy into electrical energy and/or facilitate the conversion of electrical energy into mechanical energy.

[0005] Mechanical devices actuated to perform prescribed motions for a variety of purposes are ubiquitous. Less common are actuated devices that create a prescribed, repetitive undulating motion, or effect. A variety of mechanical and/or electrical devices have come about to either harness the kinetic energy of moving fluids, or to create the movement of the fluids themselves. For example, seafaring vessels may employ a propeller, powered by a mechanical engine, to move through the water. There are also devices developed to harness the power of moving fluid, whereby an electromagnetic generator is coupled to the fluid, such as by a turbine wheel, to produce electrical energy for distribution and consumption by all manner of electrical-energy-powered devices.

[0006] Embodiments of the disclosed apparatuses, methods and systems may be directed to devices which create repetitive and/or undulating motion, or effect, to produce useful work, such as for a propulsion system or other system. These and alternative embodiments may further be directed to devices which exhibit this same undulating motion when external forces are applied, and where this undulating motion is coupled to electricity generating components. Such uses are a consequence of a functional symmetry between actuation and energy harnessing, as between an electromagnetic motor and an electromagnetic generator.

[0007] In some embodiments, flexible sheet-like members are deformed with applied force and the resulting deformation or deformations are maintained through restraining components.

[0008] In one embodiment the restraining components are vertebra plates to which the deformed, flexible sheet-like members are attached in such a manner that they are unable to return to their relaxed state. In some implementations, the vertebrae plates may be elastically or variably-coupled to a central rigid tube or member. The elastic or variable coupled components may, in various implementations, be comprised of electroactive polymer material, a magnetostrictive material, a metal coil passing through a magnetic field, hydraulic pistons, pneumatic pistons, shape memory alloy elements, and/or the like.

[0009] For propulsion embodiments, when the elastic or variable coupling components are actuated with an input of energy, such as an excitation, they will change length and impart forces onto the deformed, flexible sheet-like members, causing their deformations to shift position. In this manner the elastic or variably-coupled actuators create undulation motion along the flexible sheet-like members which may impart force onto ambient fluid to create thrust.

[0010] For generator embodiments secured in the directional flow of fluid, the kinetic energy of the fluid imparts force onto the flexible sheet-like member, causing the positions of the deformations to shift in the direction of the fluid flow. Back and forth fluid flow may cause the deformations to move back and forth. Unidirectional fluid flow may cause the deformations to travel in one direction until they move off the downstream end of the flexible sheet-like member.

[0011] Because these deformations result from the internal energy state of the flexible sheet-like member created during fabrication, these deformations cannot be eliminated so long as the restraints remain. Therefore, when a deformation moves off the downstream end of the flexible sheet-like member, another one must come into existence at the upstream end. When the mechanism is anchored in a fluid stream, a series of undulating deformations may travel continuously along the flexible sheet-like member in the direction of the fluid stream. In one generator embodiment, the flexible sheet-like members may be coupled to vertebra plates so that movement of the deformations of the flexible sheet-like members powers the movement of the vertebra plates. The movement of the vertebra plates imparts force onto the elastic or variable coupling components. The elastic or variable coupling component may incorporate transducing components which convert this force into electrical energy. The elastic coupling components may, in some implementations, be constructed of and/or incorporate an electroactive polymer or other electroactive material able to convert mechanical strain into electrical energy. The elastic coupling component may also, in some implementations, be constructed of a magnetostrictive material, a metal coil passing through a magnetic field, hydraulic pistons, pneumatic pistons, shape memory alloy elements, and/or the like.

[0012] The architecture of the system may be the same or similar for certain propulsion and pump embodiments. For example, the difference between some pump and propulsion embodiments is that the elastic or variable coupling components of the propulsion and pump embodiments are actuators rather than generators. In other words, in propulsion embodiments the elastic or variable coupling components convert electrical energy into mechanical action FIG. 1 whereas in the generator embodiments the elastic or variable coupling components convert mechanical action into electrical energy, FIG. 2.

[0013] The mechanisms, including apparatuses, methods and systems, discussed herein are not dependent on any particular actuator technology nor on any particular generator technology.

[0045] In some embodiments, flexible sheet-like members 1 are deformed with at least one applied force 2 in such a manner as to create one or more deformations FIG. 3 to form a crenated strip 3. The deformation(s) of the crenated strip 3 may be maintained via one or more restraining components. In one embodiment, this restraining component is at least one vertebra plate 4 coupled in at least one location to the crenated strip 3. The restrained crenated strip is referred to as the crenated strip fin, or CS fin 5, FIG. 4.

[0046] The CS fin 5 may be coupled, in some implementations, to a rigid or semi rigid central member 6, such as via one or more variable length or elastic tendons 7. Directional forces between the tendon 7 and central member 6 are balanced by equal and opposite directional forces of at least one other tendon 7 and one other CS fin 5. FIG. 4.

[0047] FIG. 5 shows an embodiment of a single vertebra plate 4 with multiple tendons 7 attached to the central member 6 at one end, and attached to the vertebra plate 4 via a bar connector 8 at another other end. The configuration in FIG. 5 may work equally well for propulsion and generator embodiments.

[0048] For actuated embodiments, actuation of the tendons 7 will cause them to lengthen or shorten, thereby changing the internal energy state of the CS fins 5 and thereby causing the position of the deformation, or deformations, to shift position. In shifting position relative to an ambient fluid, the deformations of the CS fins 5 may impart forces onto the ambient fluid to create a propulsive effect in some embodiments. In one embodiment, the tendons 7 may be comprised of rolled or stacked electroactive polymers, a class of materials which may contract when an electric charge is applied via electrodes. Electrical energy from a power source is converted to mechanical strain in electroactive polymer tendons 7. Adding charge to or removing charge from an electroactive polymer tendon 7 may cause the length of the tendon 7 to change. Therefore, by controlling charge to the tendons 7, the relative lengths of the tendons may be controlled. As their lengths change, the forces they impart to the CS fins 5 change and therefore the internal energy states of the CS fins 5 change, causing the positions of the deformations to change.

[0049] For generator embodiments of the invention, forces 14 from ambient moving fluid may cause the deformations of the CS fins 5 to shift in position, imparting force onto the tendons 7. This force on the tendons 7 may cause them to lengthen or shorten in some implementations. In one embodiment, the tendons 7 are comprised of electroactive polymers, which may convert mechanical energy into electrical energy through material strain and may convert electrical energy into mechanical strain, FIGS. 8-14

[0050] For generator embodiments, mechanical energy may act upon an electroactive polymer sheet with electrodes, and/or other type of transducer. In some implementations, electrical energy from the transducer passes through generator control electronics and then to power conversion circuitry, and then to an electrical output or storage device. FIG. 6. For actuator embodiments, energy from a battery or other energy source may pass through a converter and then through actuator electronics, then to electroactive polymer material via electrodes, and/or to some other transducer, which converts electrical energy into mechanical energy. FIG. 7.

[0051] FIGS. 8-11 show aspects of a sequence under operation and forces of moving water 14, showing how in one generator embodiment, the travel of deformations along a CS fin 5 correlates with rotation of vertebra plates 4 which in turn changes the length of the tendons 7 via which the CS 5 fins are coupled to the central member 6. The deformations can, in one implementation, be thought of as protruding from either side of a neutral axis and causing partial rotation clockwise or counter clockwise. FIGS. 8-11 track a single point 15 on a CS fin 5 as defined by maximum deformation and maximum rotation. The relative rotation 16 of a vertebra plate 4 may correlate with the movement of a single point 15 of deformation along the CS fin 5.

[0052] FIGS. 12-14 show aspects of a sequence under operation of a generator embodiment showing a top view of the embodiment shown in FIGS. 8-11, and tracks the travel of a single point 17 on one CS fin 5 at maximum wave amplitude, or rotation, as deformations travel along the CS fin 5 imparting rotation to the vertebra plates 4.

[0053] FIGS. 15-18 show aspects of a sequence under operation of an actuated propulsion embodiment, showing how, in one implementation, actuated tendons 7 may sequentially rotate vertebra plates 4 which impart force onto the CS fins 5 to create a propulsive force 18. FIGS. 15-18 track a single point 15 on a CS fin 5 as defined by maximum deformation and maximum rotation. The relative rotation 16 of a vertebra plate 4 may correlate with the movement of a single point 15 of deformation along the CS fin 5.

[0054] FIG. 19 shows some aspects of a generator embodiment attached to one implementation of an anchoring mechanism 19 that will hold the mechanism still in a fluid stream. In the illustrated embodiment, flexible longitudinal strips 20 enclose the vertebra plates and tendons in a longitudinal enclosure 21. For hydropower embodiments, the longitudinal strips 20 may provide a waterproof enclosure 21, FIG. 20, such as to keep electronic components dry. This waterproofing may not be a requirement for wind power embodiments. The electronic components enclosed within the longitudinal enclosure 21 may include electroactive polymer tendons, wiring, printed circuit boards, and/or the like components. In one implementation, electronic components may be housed in the anchoring mechanism 19 and connected to the generator core by a conduit 22.

[0055] FIG. 21 shows some aspects of the generator embodiment of FIG. 20 without the longitudinal strips 20 to reveal the vertebra plates 4 and tendons 7 inside.

[0056] The number of CS fins 5 may vary in different embodiments for both propulsion and generation, FIGS. 22-24. FIG. 25 shows a generator embodiment with 2 CS fins.

[0057] In yet another embodiment of the present invention FIG. 26, the CS fins 5 may be eliminated and the longitudinal strips 20 are the external surface primarily interacting with the fluid instead. In such embodiments without the CS fins 5, the vertebra plates 4 may be widened FIG. 28. During fabrication, forces may be applied to the longitudinal strips 20 in their relaxed state to create deformations in the longitudinal strips 20. The vertebra plates 4 may be coupled to the longitudinal strips 20 and elastically or variably coupled to the central member 6 via tendons 7 in some implementations. The longitudinal strips 20 are unable to return to their pre-deformed shape after being restrained via attachment to the vertebra plates 4. Therefore, undulations in the longitudinal strips 20 persist and undulations, such as traveling undulations, are expressed as partial rotation of the vertebra plates 4 clockwise and counterclockwise.

[0058] Rotation of the vertebra plates causes the lengths of the tendons 7 to change. FIGS. 29-33 illustrate aspects of a vertebra plate 4 undergoing a sequence of clockwise rotations and show how the tendons 7 change length with rotation in one implementation. FIGS. 34-38 illustrate further detail from the same sequence with the vertebra plate 4 removed from view but with rings 23 that couple the vertebra plates to the tendons remaining visible.

[0059] Several of these embodiments may be attached to a vessel to propel the vessel through fluid. In one implementation, one device is attached to the vessel, and in alternative embodiments, multiple devices may be attached. The device may be attached to the vessel by, for example, connecting the central core member to the vessel. This connection may be made with screws, glue, gusset plates, or other connecting mechanism. Alternate means of connection may also be implemented.

[0060] FIG. 27 illustrates an example of a free-swimming propulsion embodiment 25.

[0061] In yet another implementation of the propulsion embodiment, the central member 26 is flexible and may be induced to bend in any direction via one or more actuated longitudinal tendons 27 which connect to each other end-to-end forming one or more rows of longitudinal tendon 27 lines that run parallel to the flexible central member 26, FIGS. 39-40. Actuation of the longitudinal tendons 27 causes them to change in length. This change in length may occur by applying and releasing voltage, current, pressure, a magnetic field and/or the like. Three or more rows of longitudinal tendons 27 allow control of direction of movement of a free-swimming propulsion mechanism 25. The longitudinal tendons 27 are fixed to the flexible central member 26, such as by radial arms 28 and may be arranged relative to the flexible central member 26 so that one line is above and one line is below the flexible central member 26, and one line is to one side of the flexible central member 26, and one line is to the other side of the flexible central member 26, such as in a cross-shaped pattern. Reducing the length of only the upper line of longitudinal tendons 27 will cause the central axis of the mechanism to curve upward. Reducing the length of only the lower line of longitudinal tendons 27 will cause the central axis of the mechanism to curve downwards. In the same way, reducing the length of the line of longitudinal tendons 27 on only one side causes the central axis of the mechanism to curve towards that side, and the mechanism will veer in that direction.

[0062] In one implementation, each line of longitudinal tendons 27 may be supplied with an actuation circuit and a sensor circuit connected electronically to a microcontroller 29, which may control the length of each via actuation of the line of longitudinal tendons 27. In this manner, the microcontroller may cause the direction of travel of the vessel to change by causing the longitudinal central axis of the mechanism to curve, causing the vessel to alter its course from a straight trajectory to a curved trajectory. The longitudinal tendons 27 may be comprised of a number of different materials, such as electroactive polymers, shape memory alloys, carbon nano-tubes, and/or any other of a variety of existing and emerging materials in which the material will change shape when actuated by electric charge, heat and/or other input. In addition, these actuated components described above may be actuated pneumatically or hydraulically using assemblies of components such as pumps and valves coupled to such final actuators as pistons, diaphragms and/or other actuators. Methods by which such components may be induced to change the shape and/or length may be applied, so that the arrangements described above will produce the desired actions described above, whichever materials/components are used.

[0063] Some of the propulsion and generator embodiments disclosed thus far have utilized rotary reciprocating motion of the vertebral plates, with the CS fins 5 coupled to the vertebra plates 4 so that the CS fins 5 undulate substantially in-phase with each other FIG. 41. The longitudinal strips 20 also undulate substantially in-phase with each other in such embodiments. In another implementation, the CS fins 5 may rotate in substantially opposite directions relative to each other to create a bilateral reciprocating action FIG. 42.

[0064] Bilateral reciprocator 30 embodiments may be configured with a central member 6 coupled on opposite sides by tendons 7 that, as with embodiments utilizing rotational motion, may be actuators for propulsion embodiments or energy harnessing components for generator embodiments. The forces within the deformations of the CS fins 5 are transferred first to the longitudinal strips 20 and then onto the tendons 7 and then onto the central member 6. Each tendon 7 may, in one implementation, be coupled at one end to the central member 6, such as via a tension bracket 31, and may be coupled at the other end to the junction point 32 of two longitudinal strips 20, such as via a tension hanger bracket 33, FIGS. 43-47.

[0065] FIG. 44 illustrates some aspects of assembled details of a bilateral reciprocating embodiment.

[0066] FIG. 45 illustrates some aspects of a bilateral reciprocating embodiment with its longitudinal strips 20 removed.

[0067] FIG. 46 illustrates some aspects of a bilateral reciprocating embodiment with its CS fins 5 removed.

[0068] FIG. 47 illustrates some aspects of a bilateral reciprocating embodiment of FIG. 46 with its CS fins 5 removed and its longitudinal strips 20 removed.

[0069] Actuator embodiments of the bilateral reciprocator 30 utilizing electroactive polymers may be employed to address the challenge of electroactive polymer actuation in which tension force is desired: The potential energy stored in the CS fins during the fabrication process from the force 2 used to create the persistent deformations of the crenated strips 3 that forms the CS fins 5, is redistributed within the CS fin 5 when charge is selectively applied to tendons 7. Therefore, rather than actuation of a tendon 7 causing it to contract and exert propulsive force onto the CS fin 5, actuation of a tendon causes it to elongate, which causes deformations to shift via the elastic forces loaded as potential energy during fabrication.

[0070] Described another way, the tendons of propulsion embodiment are not actuated to exert tensile force. The tensile forces in the entire mechanism are present due to deformation forces during fabrication. Actuation of tendons may cause them to relax, thus changing the balance of forces and causing the stored potential energy to release, thereby initiating motion in the tendons 7 and therefore also in the CS fins 5.

[0071] Some actuator and generator embodiments may also be described as follows:

[0072] Two or more crenated strips 3 or deformed members 3 elastically coupled to a rigid or semi rigid central member 6 via tendons 7 so that the deformation energy of one deformed member 3 is shared with every other deformed member 3 in dynamic equilibrium.

[0073] A rigid or semi rigid central member 6 symmetrically coupled via tendons 7 to at least two deformed members 3 with the potential energy of the deformations in the deformed members 3 held in equilibrium by the transfer of forces between the deformed members 3 via the tendons 7.

[0074] A central rigid or semi-rigid member 6 elastically coupled via tendons 7 to at least two deformed members 3 whose internal energy states communicate via the tendons 7 and rigid or semi-rigid member 6 so that the internal energy states of the deformed members 3 are in equilibrium.

[0075] Energy from an external source such as the kinetic energy of moving water or air causes the deformations of the deformed members 3 to shift and in so doing impart energy onto the tendons 7 from which energy may be harnessed. An input of energy into the tendons 7 causing them to expand or contract imparts forces onto the deformed members 3 causing the deformations therein to shift and thereby imparting force onto ambient fluid such as air or water to create a propulsive effect.

[0076] This disclosure describes inventive aspects, including at least the following:

[0077] It is to be understood that the tendons 7 of propulsion and generator embodiments may be configured as transducers and may be comprised of a number of different components. Embodiments discussed herein are directed to novel mechanical components and their novel assembly which effectively transfer forces to the tendon 7 transducers, or transfer forces away from the tendon 7 transducers. Therefore, this invention may couple with other components not described explicitly. Examples include adaptations whereby the tendons 7 are pneumatic tubes or pistons which may pump a fluid for the purpose of pumping, and/or to drive a conventional electromagnetic generator.

[0078] It is to be understood that while the embodiments discussed herein focus on examples utilizing electroactive polymer materials for the tendons 7, the mechanical principles brought to bear work equally well for embodiments in which the tendons 7 may be any elastic or variable length transducer. Embodiments discussed herein are directed to the design, arrangement and functioning of mechanical components acting upon tendons 7, which are transducers for propulsion or energy harnessing.

[0079] The deformed member 3 or CS 5 fins described herein may also, in some implementations, be comprised of a segmented sheet-like material, such as one having portions which are stiffer coupled to each other by portions or joints which are less stiff.

[0080] FIG. 48 illustrates some aspects of a generator embodiment in which the transducer of at least one vertebra is an electromagnetic generator 34 rotationally coupled to the vertebra plate 4 and fixed to the central member 6. Traveling undulations of the CS fins 5 cause rotational movement of the vertebra plates 4 as described above, generating electricity in the ring generators 34 which may be fixed in position relative to the central member 6.

[0081] FIG. 48 also illustrates some aspects of a propulsion embodiment in which the transducer of at least one vertebra is an electric motor 35 rotationally coupled to the vertebra plate 4 and fixed to the central member 6. Actuation of the electric motor 35 causes the vertebra plates 4 to rotate which imparts force to the CS fins 5 which impart force onto ambient fluid

[0082] Some propulsion embodiments may also be described as follows:

[0083] Two or more deformed flexible members 3 symmetrically coupled to a fixed central member 6 so that the potential energy in the deformations of each flexible member 3 are in equilibrium with the potential energy in the deformations of every other flexible member 3, and where the coupling mechanism is a transducer, and whereby an external energy source 14 causes the distribution of potential energy in the flexible members 3 to change and transfer energy to the transducers which harness the transferred energy. The transducer may be electroactive polymers, electromagnetic generator, etc.

[0084] Two or more deformed flexible members 3 symmetrically coupled to a fixed central member 6 so that the potential energy in the deformations of each flexible member 6 are in equilibrium with the potential energy in the deformations of every other flexible member 6, and where the coupling mechanism is a transducer, and where actuation of the transducer imparts force onto the flexible members 3 causing the distribution of potential energy in the deformed flexible members 3 to change and to transfer force onto the deformed flexible members 3 thereby creating a propulsive action 18. The transducer may be electroactive polymers, electromagnetic motor, etc.

[0085] FIG. 49 shows an exemplary embodiment of transducer excitation. A plurality of transducers may be affixed in sequence in a direction of desired wave propagation, wherein the plurality of transducers are each affixed at a first end to a first restraining component 4901. The second end of the plurality of transducers may be affixed to a second restraining component, wherein the plurality of transducers are maintained in ma state of excited equilibrium by connections to the first and second restraining components 4905. In some embodiments, the maintained state of excited equilibrium may be caused by an elongation of tendons, an applied pressure, and/or the like. An excitation signal may be applied to a first group of transducers, wherein the excitation signal causes a release in the transducer of mechanical resistance to forces imparted by the first and second restraining components 4910. The excitation signal may, in various embodiments, be a voltage, current, pressure, magnetic field, and/or the like. In some implementations, the strength of the excitation signal may be determined based on, for example, wave length, wave speed, wave frequency, historical values, sensor data wherein the sensors may track factors such as stress or displacement, and/or the like. Conditions may be monitored via a processor, CPU, microcontroller, and/or the like to determine the next excitation 4915 and a determination of whether the next excitation condition is satisfied 4920. The processor, CPU, microcontroller, etc., may also determine how much, where, and when excitation should be applied. The conditions may be based on, for example, whether sensor data such as a force or displacement exceeds or drops below a certain value. For example, the sensors may measure force in the tendons or displacement in the CS fins relative to a certain threshold. In an alternative embodiment, the condition may be based on a set passage of time and/or a model that indicates a signal should be sent to a certain part at a certain time. For example, in some implementations, sequence programming in the memory or data structures may include time, place, and the amount and/or type of excitation to apply as it relates to the propagation of a wave. If the condition is not met, the system may wait for a predetermined period of time 4925 or, in an alternative embodiment, continually loop to monitor for the next excitation 4915. When the next excitation condition is satisfied 4920, an excitation may be applied to the next group of transducers 4930. In some embodiments, as the wave propagates, the amount of excitation applied may decrease; that is, as motion propagates through the CS fins, the tendons may require less excitation. In some implementations, sensors may measure a restraining force, which may then be compared to a threshold value to determine the amount of excitation to apply. Further embodiments may show that when the excitation occurs in one group of transducers, the force on the second group of transducers is increased. In alternative embodiments, the force on the second group of transducers may be decreased after excitation occurs in the first group of transducers. If there is another group of transducers 4935, the system may monitor for the condition for the next excitation 4915; if there are no more groups, the loop terminates 4940.