WO2017070106A1

WO2017070106A1 - Momentum transfer or impulse based linear actuator systems to control movement and velocity of objects and methods for such

Info

Publication number: WO2017070106A1
Application number: PCT/US2016/057516
Authority: WO
Inventors: Faranak Davoodi
Original assignee: Faranak Davoodi
Priority date: 2015-10-18
Filing date: 2016-10-18
Publication date: 2017-04-27

Abstract

A method for controlling the movements of a freely floating craft in a low- or zero-gravity environment or in a low-friction environment, wherein the movements are brought about by imparting a momentum to the craft using a series of linear or impulse actuators.

Description

Momentum Transfer or Impulse Based Linear Actuator Systems to Control

Movement and Velocity of Objects and Methods for Such

Related Applications

[0001] This application claims the benefit of U.S. Prov. Apps. 62/243.083, filed October 18,

2015, 62/243,328, filed Oct. 19, 2015, 62/259,059, filed Nov. 24, 2015, 62/404,201, filed Oct. 5, 2016 and 62/404,767, filed Oct. 6, 2016.

Field of the Invention

[0002] This invention related to methods for controlling the orientation, trajectory, or velocity of floating or low friction objects, such as cubesats in zero gravity orbit of the Earth, and, in particular, to the use of a combination of one or more momentum transfer or impulse based linear actuators integrated into the structure of the floating or low-friction objects to accomplish the control and methods to use such systems.

Background of the Invention

There are numerous small or large floating objects in zero or low gravity environments, for example, satellites that perform various tasks. These floating objects usually utilize one or more subsystems such as an imager or a laser communication system that would perform and work better if adjusted and positioned towards some specific direction or aimed correctly towards a specific target. [0004] Traditionally, the position and orientation of such floating objects were controlled using gas (for example, CO2) or fuel-based thrusters to push the floating object to change its orientation. The problem with this method is that a consumable substance is required for the thruster to operate. The CO2 or fuel stored in the floating object is very limited in quantity and will be exhausted at some point, rendering the floating object uncontrollable. Another problem is that gas or fuel-based thrusters are difficult to control and require a lot of power to operate, thereby making the control and positioning of the floating object extremely challenging.

[0005] The use of hexa-axle linear actuator system to provide a motive force to ground-based objects (i.e., objects in gravity environments) is known. U.S. Patent 8,912,892, describes such a system wherein linear actuators are used to change the center of mass of an object, thereby allowing gravity to act to impart a motion on the object. This is especially effective for spherical- shaped objects, which can use this method change position by rolling along a surface. This method is ineffective, however, in low- or zero gravity environments or low-friction environments.

Summary of the Invention

[0006] Disclosed herein are novel techniques of using momentum transfer and impulse-based linear actuators for control of the trajectory, orientation, and velocity of the floating objects in low- or zero-gravity environments as well as in larger planetary bodies such as the Earth, the moon, or Mars all with gravities of different magnitude and in low-friction environments. The techniques are based on momentum transfer or impulses generated by one or more linear actuators comprised of one or more tubes in which one or more internal masses move under the influence of internal propelling forces such as the magnetic, electric, or mechanical forces. The mechanical impulse of the moving masses colliding with the structure of the floating object at the ends of tubes, or the torque generated on the floating object where there are magnetic pads or parts are integrated to the end of the linear actuators and the torque is generated by the magnetic moment of the moving magnetic, the ferromagnetic, or electromagnetic mass or the dramatically increasing magnetic field of the moving or stationary electromagnetic solenoids toward a fixed ferromagnetic or magnetic pad or part at the end of the linear actuators and where it get integrated to the structure of the floating object would affect the velocity, trajectory, or the orientation of the floating object. The faster the mass is able to move, and the larger it mass, the larger its momentum will be. Moreover, the smaller the mass of the floating object and the faster it is moving, the easier it is to control. Alternatively, the stronger the magnetic moment applied to the magnetic parts attached at the end of the tubes and the floating object, the faster the object would move. Disclosed herein are example embodiments of such impulse based linear actuator system and the floating objects and the applications and methods using such systems and objects. Introduced herein is a control system comprised of one or more momentum transfer or impulse based linear actuators for the floating objects, such as spacecraft. The advantage of this disclosure over prior art spacecraft using the gas-thrusters is that there are no requirements for consumable substances to operate the actuator. The actuators operate on electrical power, which can be generated by any one or a number of means, including, for example, using solar cells or harvesting power from the motion of the floating object. [0008] The impulse-based control techniques and the magnetic levitation techniques disclosed herein could utilize the linear actuators described in U.S. Patent 8,912, 892. Even in gravity environments, the performance of a spherical structure would be increased by eliminating the friction between the moving magnet mass and the tubes and exerting extra magnetic or mechanical momentum transfer force to the spherical structure, even if it is operating on the Earth or on planetary bodies with different gravities, such as Mars or the Moon.

Brief Description of the Drawings

[0009] Figure 1 shows a first embodiment of an impulse-based linear actuator, the use of which is described herein.

[0010] Figure 2 shows a variation of the embodiment of Figure 1 wherein multiple solenoids can cooperate with other to move a magnet from one location to another location.

[0011] Figure 3 shows an additional embodiment of an impulse-based linear actuator wherein the magnets are fixed and a solenoid moves inside the linear actuator.

[0012] Figure 4 shows a variation of the embodiment of Figure 1 having fixed permanent or electromagnets integrated with the device to keep the magnet suspended when moving and thereby eliminating the friction.

[0013] Figure 5 shows an example embodiment of an impulse-base linear actuator system

comprised of four impulse-base linear actuators, which are attached to each other with some angle in the middle. The main control decision-making system control system is shown in the middle of the actuators.

Figure 6 shows an example embodiment of a craft for special environment (as defined below) operations having an impulse-base linear actuator system comprised of 12 impulse-base linear actuators connected to each other, and two main control systems, integrated therein.

Figure 7 shows an example of the network of the spherical craft having an impulse-based linear actuator system comprised of 6 impulse-base linear actuators connected to each other and one main control system, integrated therein.

Figure 8 shows an example of the network of the spherical craft in a low gravity environment. Each spherical craft is similar to the example embodiment of Figure 7, and is equipped with a wireless communication system such as RF and optical. They use impulse-base linear actuator systems to control orientation and therefore are able to control and point the communication antenna to the desired location on the ground or towards each other and other craft.

Detailed Description of the Invention This invention related to methods for controlling the orientation, trajectory, and the speed of the floating objects (100), using a combination of one or more impulse-based linear actuators (500) to accomplish the control. For purposes of this disclosure, the term craft (100) or floating object (100) shall mean any object operating in a special environment, as defined below, requiring control of either position (orientation), speed or trajectory; or its angular or translational velocity and displacements. The floating object (100) mentioned in this disclosure can be of any shape such as a cube, sphere, cuboid, cylinder, pyramids, polygon, polyhedron, polytopes, car-shape, boat-shape, or combination thereof. Some examples shall include, but not be limited to spacecraft (manned or unmanned), satellites, orbiters (including, for example, Cubesats, Nanosats, or Spheresats), antenna, including inflatables, spherical shaped, flat, etc., space- stations such as cargo space stations, science space stations, colonization space stations (where humans could stay in orbit), docking stations (where other spacecraft could attach), transportation spacecraft including trans-planetary spacecraft, space-capsules, launching vehicles, rockets, re-entry vehicles (e.g. similar to shuttles or dragons), landing systems, including aeroshells, landers, planetary probes, etc., space planes, dragon space-craft, balloons, drones, or any other spacecraft that could also be an airplane when in the atmosphere, space robots, various robots in different shapes and capabilities that could be used in an orbiter, docking systems, smaller planetary bodies, etc., space-telescopes having structures similar to ones from Hubble, Chandra, Spitzer, Herschel, Plank, etc., and any other floating object in a fluid environment which could be suspended and which could have free (or near free) movements, or have a high speed, including, rockets, missiles, cannon balls, or bullets in the atmosphere or probes, submersibles or torpedoes in a marine environment. Other examples of craft (100) include, but are not limited to various toys or sport balls, buoys, ships, submarines, drones, spherical structures, balloons, airplanes, dragon capsules, launch vehicles, medical devices or micro-robots injected to the body to perform medical diagnoses or treatment or for the delivery of various substances, include medications.

[0019] The term "special environment" shall include both a "low gravity environment" and a

"low friction environment". The low gravity environment shall mean outer space, artificial vacuums or low gravity or zero gravity environments on Earth, various orbits of the Earth or other planetary bodies, the in-situ surface of smaller planetary bodies (such as asteroids) or space objects, or any environment and situation where the floating structure (100) could stay afloat, suspended, or have free movements. Such environments could also include fluids, such as liquids, gasses, oceans, atmospheres, etc. In some cases, the environment might not be a vacuum. The low friction environment shall mean on the ice, or any other hard surface, or the fluid such as the oceans, rivers, blood stream, where the craft (100) such as a light balloon, a cylinder or sphere, has low friction with the surface or the environment and is able to roll, rotate, or slide. Such low friction environments also include the ground and floors of the factories, warehouses, roads, inside parts of the machineries, toys, robots, vehicles, or human body.

[0020] Each impulse-based linear actuator (500) is comprised of a tube (504) or a shaft (504) with two ends (503) that are attached to the structure of the floating object (100) with one or more moving masses or one or more stationary solenoids inside or along the shaft (504) or the tube (504). The moving masses (501) inside the tubes or through the shafts (504) slide along the linear actuator (500) and impact the connection point between the end of the tube (503) and the floating object (100) thereby colliding with floating object (100) and generating an impulse that could make floating object (100) move. In one embodiment, the moving masses (501) speed up when moving in one direction towards the end of the linear actuator (503) and then retract slowly, using a mechanical propulsion system such as a hydraulic pump, piston, or heating units that expand or compress a fluid (for example oil or air) inside the tube (504). Alternatively, the moving mass could be magnetic and made of ferromagnetic or magnetic material or

electromagnetic solenoids. Under the influence of external electromagnetic forces generated by solenoids or magnetic or ferromagnetic parts integrated inside and along the tube (504), moving mass (501) would collide into the floating object (501) (at the point of connection between end of tube (503) and floating object (501)) thereby creating an impulse, or creating a magnetic pulse, momentum, and torque against the ferromagnetic and electromagnetic parts of the floating object where it joint the end of the tubes (503). As a result, the rotational or translational movements of floating object (100) could be changed.

In another alternate embodiment, one or more stationary electromagnetic solenoids can be impulsed with a burst of electricity to create a burst of magnetic field and moment against those magnetic parts joining the end of the linear actuator (503) and a magnetic torque would be created at the point where the end 503 of tube 504 is attached to the structure of the floating object 100, which would make floating object (100) move and change its direction, orientation, and/or velocity (both angular and translation movement and velocity).

The main application of the collection of the impulse-based linear actuator system (500) and method of the present invention is for craft (100) for which the direction or orientation can be easily changed by a change in momentum generated by the impact of a moving mass (501), an electromagnetic impulse or the quick movement of an internal moving magnetic mass against a ferromagnetic or magnetic joint pad attached to the end of the impulse-based linear- actuator (500). The systems and methods disclosed herein are able to create momentum and forces that can move a craft (100) translationally (i.e., when the entire craft moves from one location to another), or which can make changes in the velocity or the direction (or trajectory) of the craft already moving along a path (i.e., using its own internal or external propulsion) or which can change the rotational velocity or the orientation (or angular displacement) of a stationary or already rotating craft (100). The orientation of a craft (100) is the direction and status of the structure of the craft (100) in relation to its surroundings. For example, if the solar panel of a spacecraft is in the opposite direction of the sun, the control system disclosed herein could rotate the craft about its rotational axis, or along its symmetrical axis, to place its solar panel towards the sun. The system and method disclosed here is based on the momentum transfer or impulse generated by one or more linear actuators comprised of one or more tubes (504) in which one or more internal masses move (501) under the influence of internal propelling forces such as the magnetic, electric, or mechanical forces. The transfer momentum created thereby is transferred to the floating object (100). The mechanical impulse of the colliding moving masses (501) to the structure of the floating object at the end 503 of tube 504 generates a torque on the floating object by the magnetic moment of the moving magnetic, ferromagnetic, or electromagnetic mass or the dramatically increasing magnetic field of the moving or stationary electromagnetic solenoids toward a fixed ferromagnetic or magnetic pad or part at the end of the linear actuators (503). The faster the mass (502) is able to move, and the larger it mass, the larger its momentum will be. Moreover, the smaller the mass of the floating object and the faster it is moving, the easier it is to control. Alternatively, the stronger the magnetic moment applied on the magnetic parts attached at the end of the tubes (503) and the floating object, the faster the object would move.

Each impulse-based linear actuator (500) is integrated into the structure of the floating object. The moving mass (501) inside the tube 504 (i.e., the body of linear actuator (500)) is accelerated (505) and moved to the end 503 of tube 504 and mechanically collides with the structure of the floating object (100). The mass, speed, and the structure of the moving mass (501) and the strength and the elasticity of the structure of the floating object (100) and the point of connection between floating object 100 and linear actuator 500, are such that the generated impulse makes the moving mass (501) impact the elastic structure of the floating object 100 while the floating object (100) moves forward or rotates. The result of such impulse will be based on the Impulse Momentum Theorem and the conservation of momentum and energy. For example, assume the moving mass (501) with mass YYIM and initial velocity of VMi elastically collides the floating object (100) with mass J71F and initial velocity of VFi on the surface of a micro-gravity body such as an asteroid (therefore no friction exists between the floating object and the surface of the planetary body). Also assume that there are no energy waste due to heat or material deformation, or the friction between the moving mass (501) and the tube (504) (for example by applying maglev techniques mentions later in this disclosure), no heat, material deformation, or any other energy waste. Then final velocities of the floating object (100) VMf and the floating objects VFf are approximately as following:

VMf = ((mM-mh) I (mM+mF))vMi + {1i /( inM+mh) )V L VFf = ({mh - MM) I (mM+mF))vFi + ( 2IHM/( inM+m ) ) VMI

[0025] Alternatively, the magnetic force and torque generated by the magnetic fields of the internal actuator's magnet (which is the moving or stationary magnet (501) or stationary electromagnetic solenoid (502)) with moment ml on the floating-object's magnet (which is the electromagnetic part of the floating object (100) joint at the end of the tube (503)) with moment m2, and when there is a magnetic field of B l between them caused by the moment of the internal actuator's magnet, could correlate with the following formula:

[0026] The force exerted by the internal actuator's magnet with moment mi on the floating- object's magnet with moment m₂ is

If — (lilt * Hi ) j The result of calculating the gradient is

Where f is the unit vector pointing from the internal actuator's magnet 1 to floating- object's magnet 2 and r is the distance between them. An equivalent expression is F— "^■»■-"^■■ {(* x mi) x mg -f (? x m¾) x m*™ * ***¾) 4- x m%} * (i x m )}

The force acting on the internal actuator's magnet mi is in the opposite direction. The torque of internal actuator's magnet 1 on floating-object's magnet 2 is

[0027] The magnetic mass and parts mentioned in this disclosure are made of known magnets,

such as alnico magnets, bonded magnets, ceramic (ferrite) magnets, flexible rubber magnets, neodymium iron boron (NdFeb) magnets, and samarium cobalt magnets, etc.

The stationary or moving electromagnetic solenoids with coils made of electrically conducting materials such as copper, silver, gold, or high temperature or regular

superconductors material such as Bi-2223 (Bismuth 2223) or ReBCO (Rare earth Barium Copper Oxide).

[0028] Different parts of floating-object or the craft (100), and different parts the linear actuator

(500) including its tube (504) or the shaft (504) is preferably composed of ethylene tetrafluoroethyle (ETFE) or any other fluoropolymers (such as Teflon-PTFE, FEP, PFA, PVDF, PCTFE, ECTFE, Vespel, Meldin, PEEK, etc. with their exceptional properties such as being extremely pure (with almost zero percent metal in it) which could be used as magnetic and electric jackets, or being able to resist the extreme temperatures (-300F to + 300F), while act as thermal insulations, being extremely elastic and tensile resistant, extremely low friction, anti- fouling (when used in the Earth's oceans, so no algae would attached to it). Based on the special environment that the floating-object (100) and the linear actuator system (500) need to operate, they may be constructed using other materials such as PVC, or Kevlar, Dyneema, Polyurea, PVC, polyurethane or fiberglass.

Figure 1 shows an example embodiment of the invention consisting of a single impulse- based linear actuator (500) consisting of tube (504) through which one or more magnetic masses (501) may move under the influence of coils (502).

Passing electrical currents through coils (502) creates a magnetic field that could either attract or repel the moving magnet(s) (501), depending on the direction of the current. If the direction of the current in coil (502) is such that the magnetic pole of the moving magnet (501) is opposite the magnetic pole created by the coil (502), the moving magnet will be drawn towards the coil (502). However, if the direction of the current is such that the created magnetic pole of the coil (502) is the same as the moving magnet (501), the moving magnet would be repelled from the coil (502).

By controlling the direction and strength of the current passing through coils (502), based on the well-known Faraday's Law of Induction, the moving magnet (501) can move (505) from one location in tube (504) to another location in tube (504), at varying speeds.

For example, in Figure. 1, the coil near Location 0 could repel moving magnet (501) from Location 0 towards Location 1. Meanwhile, the coil near Location 1 could attract moving magnet (501) towards itself. If it is desired that moving magnet (501) pass Location 1, then the coil near Location 1 could either be switched off or the direction of the currents going through the coil can be change to be able to repel moving magnet (501) to ensure that the moving magnet (501) would stop in its target location. The appropriate location or desired target for the moving magnet to stop might be based on our calculation on what would be the appropriate force and torque on the magnetic pad or part of the floating-object (100) which is attached to the end of the tube (503). The right timing for switching the coils (502) is critical for the proper positioning of moving magnets (501), the torque applied to the craft (100), and also for making the overall system energy efficient. For example, we may want to make the coil (502) near Location 1 be activated (by passing an appropriate currents through it) and energized only when moving mass (501) is within the effective range of the electromagnetic field of the coil.

[0033] In one example embodiment of the impulse-based linear actuator (500), moving magnet

(501) might need to pass through Location 1 and strike the structure of the craft in which it is installed, which would preferably be attached to the end of the tube (503), to impart an even larger momentum to the craft. Preferably, the end (503) of tube (504) will be connected to the structure of the craft via sturdy connection points using fluoropolymers, (e.g. ETFE), Titanium, Polyurea, Kevlar, etc. to protect it from damage due to continuous strikes by moving mass (501).

[0034] In a variation of an embodiment of linear actuator 500, Figure 2 shows an example

embodiment of linear actuator (500) using multiple coils (502). This variation is especially useful if magnet (501) is smaller, compared to the length of tube (503), or if the available source of energy is not powerful enough to pass strong currents through coils (502). In this case, the directions of the coils (502) should change in turn from attraction, to neutral, to repelling to make the moving magnet (501) move from Location 0 to Location 1, passing through several of the coils (502) on the way. [0035] An intelligent control system is integrated inside the floating object (100) or the craft (100). The control system (101) comprised of some position and situation sensors and detectors which could detect the orientation, trajectory, direction, and the speed of the craft (100) and then control the position and speed of the moving magnets (501), to adjust the strength, direction and duration of the electrical currents that pass through the propulsion solenoids (502) or the moving electromagnets (501) and therefore to control the mechanical or magnetic impulse generates against the floating-object (100), which in turn would control the translational and rotational movements (velocity and

displacement) of the spacecraft or the floating object (100).

[0036] Some example sensors and equipment that could integrated inside the craft (100) to

detect and calculate its relative position, orientation, speed are: (1) gyroscopes such as ( ADIS 16136 AMLZ - MEMS Gyroscopes Single Axis ±450 s 24-Pin Tray - Analog Devices), (2) sun tracking sensors (SSOC-D60 2-Axis digital sun sensor or NSS Fine Sun Sensor), (3) star tracker sensors (NST-1 Nano Star Tracker), or a (4) CubeSense (CubeSense module is an integrated sun and nadir sensor for attitude sensing. It makes use of two CMOS cameras - one dedicated to sun sensing and another for horizon detection. The sun sensor has a neutral density filter included in the optics. Both cameras have wide field-of-view optics. The primary outputs of the sensor are two angles that can be used to calculate the sun and nadir vectors relative to the CubeSense camera boresights), (5) GPS (Irridium), (6) CTD or Depth, salinity, and temperature sensor such as Valeport's fast CTD Profiler (if the floating object is used in the ocean), etc. Some position sensors such as Keyence's CMOS Multi- Function Analog Laser Sensor, or Keyence's Super Small Head Compact and Lightweight Laser Displacement Sensor) could be integrated into the structure of the impulse-based linear actuator (500) in order to detect and update the position of each moving magnet alongside its tubes or shafts (504). Alternatively, an Inductive Proximity Sensor or hall effect sensor such as

Honeywell Hall Effect 103SR13A-1 or The US 1881 is an integrated Hall effect latched sensor can be integrating at the end of the tubes (503) or alongside of the tube (204) in order to detects any change in the magnetic field generated by moving magnet (501) approaching and retracting, and therefore verify its position along the tubes (504) or the shafts (504).

All of the sensory and position data could wirelessly transfer to the main decision making controller and vice versa, using micro transceivers such as Bluetooth (e.g. Digi-Key 1528-1199-ND), ZigBee (e.g. Digi-Key XB24-AWI-001-ND), or optical (XFP-10GZR- OC192LR). The main decision making controller is comprised of hardware and software control and data processing systems such as a controller, data logger and processor (for example Adafruit Trinket Mini Microcontroller 3.3V and 5V Logic using the ATtiny85 or Arduino, etc.) as well as communication transceivers (wireless ZigBee, Bluetooth, optic, etc.). The data received from various sensors and controlling systems (such as the controlling electric circuits that would adjust the currents passing through the solenoids (502)) will be received by the main controller and will be processed to determine the adjustments required to control the moving magnets (501), generated impulses, and therefore, the translational and rotational movements of the floating-object (100). The calculated information and value of the adjustments to different parts of the system will be then transferred to the related parts (e.g. the solenoids (502)) via wireless micro transmitters such as the ones mentioned above. Preferably, the currents required to activate the solenoids (502) and move the magnets (501) are generated through a controllable electrical circuit, which would use a battery or a capacitor to create voltage and current, under control of the main decision making control system (101). The electrical power required to operate the control system and to energize the coils (502) can be generated by any one or a number of means, including, for example, using solar cells or harvesting power from the motion of the floating object (100) to charge the system's battery or capacitors. An example of such power system could be GOMSpace 3U power pack which includes the solar cells, the capacitor, rechargeable battery, solar light tracker, etc.

The main controlling system (101) could get integrated inside a protective chamber made of ETFE (or other fluoropolymers elastomers such as Teflon- PTFE, FEP, PFA, PVDF, PCTFE, ECTFE, Vespel, Meldin, PEEK,), polyurethane, Titanium, Polyurea, or a combination of them, to protect its electronics and sensors, from the internal and external vibrations and movements, or harmful radiations (e.g. solar winds or radio waves). The main controlling system (101) (inside its protective container) could get integrated anywhere inside the floating object (100), and perhaps in the middle of the collection of impulse-based actuators (500) (as shown in Figure 5) or in the middle of the floating- object (100) and the integrated collection of the impulse-based linear actuator systems (500) inside it and as shown in Figure 6.

Additionally, when there are several coils (502) along the tube (504), the coils (502) can be made to act as a single unit (similar to having a phase-array magnetic field) to create a stronger moving power for magnetic mass (501) towards a given direction and the required speed to create the desired impulse and torque on the body of the floating-object (100).

[0041] In yet another variation, moving magnets (501) could be coils when electrical currents are passed through them (i.e., they could be inductive). The coils for moving magnet (501) could be made of superconducting materials such that an extremely strong magnetic field is generated. Moreover, a combination of superconducting techniques and temperature differences could be used to make the coils and coil-magnets switch off and on to control the speed and location of the moving objects (501) inside the tube. There are several superconducting materials such as Bi-2223 (Bismuth 2223) or ReBCO (Rare earth Barium Copper Oxide) that could work for this in the extremely cold environments of outer space and planetary bodies far away from the sun.

[0042] The coils (502) located at the ends of the tubes also can act as dampers to slow down the fast moving magnet (501), if needed, to ensure that it would not hit and possibly damage the interface structures (503) at the end of tube (504) and the structure of the craft.

Conversely, the coils (502) located at the ends of the tubes could act as accelerator to the moving magnet (501) and therefore create a stronger impulse or magnet moment and torque against the floating-object (100).

[0043] Figure 3 shows another example embodiment of the linear actuator (500) that consists of a tube axle (504) where there are one or more stationary permanent magnets (501) integrated into the structure of the tube (504), and the moving object creating the momentum are moving coil(s) (502). The moving coil (502) could be moved from one location to another within tube (504), for example, along direction (505), under the influence of stationary permanent magnet (501) located near interface (503), when there is a current is passing through coil (502). The stationary permanent magnets (501) could actually be other coils with a current passing through them. Moreover, the coils could be made of superconductors, with example material mentioned in this disclosure.

In another variation embodiment of the impulse-based linear actuator (500), static permanent or electromagnetic magnets are wrapped around the tube (504) or the shaft (504) to create a magnetic levitation effect thereby suspending the moving magnet (501) or electromagnet solenoids (501) and (502) inside the tubes. This variation eliminates any concerns regarding friction between tube or shaft (504) and moving magnet (501). An example embodiment of such design (500) using magnet levitation is shown in Figure 4. The example embodiment (500) is very similar to the high-speed trains with sets of static or electromagnets integrated on the lining of the tube to create magnet levitation (511) of the moving magnet (501). Once the moving magnet (501) is floating, the propulsion electromagnetic solenoids (502) could get activated and supplied with a controlled alternating current, which causes the electromagnetic solenoid (502) to switch polarity. By spacing the coils (502) with appropriate gaps alongside the tube 504, the moving magnet (501) is first attracted to the electromagnets (502) in front but later repelled by them as it passes over them. This will make the moving magnet (501) to move inside the tube from one location to the other while under magnetic levitation effect and no friction. Alternatively, and if a shaft (504) going through a hole inside the moving magnets are used (501), then the entire shaft could get covered either by electromagnetic coils or the static permanent magnets, with different magnetic polarity with the parts of the moving magnet (104) around the shaft (504) to create a magnetic levitation effect and help the moving magnet to float around the shaft and therefore eliminate the friction. ETFE or PTFE resins could also be used as extremely efficient lubricants in extremely cold environment between the moving magnet (501) and the tube (504) or the shaft (504), if maglev techniques are not used.

[0045] One or more impulse-based linear-actuators (500) could get attached to each other (using bounding techniques such as heat-sealing, various glues, or mechanical stranding techniques or O-ring, etc.) with an angle (5001) such as 180 degree or along each other, perpendicular to each other, or with any degree of angle (5001), to create a combination or collection 5000 of the impulse-based linear actuator system. Figure 5 shows an example embodiment of such combination impulse-based actuator system (5000) comprised of 4 impulse-based linear actuators (500a, 500b, 500c, 500d), which are connected to each other with some angle (5001) and wherein the main control system (101) is integrated in the middle of the impulse-based actuator system (5000).

[0046] The combination 5000 of impulse-based linear actuators are mounted in in various parts and places with respect to the structure of the craft (100) and with respect to each other, to control the orientation movement (rotation velocity and rotation displacement), or translational movement (translational trajectory, speed, or displacement) of the craft (100). An example embodiment of such arrangement is shown in Figure 6. Each impulse-based linear actuator (500) consists of one or more moving magnetic masses

(501) and stationary coils (502) (or the reverse arrangement as discussed above). The momentum of the moving magnets (501) attracted or repelled by the stationary coils

(502) inside the craft (100) impart a momentum to the craft (100) to make it turn, flip, rotate, slide, lean, steer, or move to one side or along a given direction. The main control systems (101a) and (101b) inside protective chambers are integrated inside the floating object (100) and in two locations (101a) and (101b) in the middle of the collection of the impulse-based linear actuators (5000)

In a method of changing the orientation of a craft, the control system would effect a desired change in orientation, trajectory, and speed of the craft (100). The required change in orientation could be due to a deviation from a pre-programmed position or to achieve an orientation received form an off-board source (101). Preferably, the craft (100) will be equipped with a communication system (103) to perform external communication with some base-stations such as a satellite and receive off-board instructions. Depending on the sophistication of the programming aboard the control system of the craft (101), the craft could receive, from the off-board source, a desired final position, in which case it would calculate the required series of movements of said masses to achieve the desired final position. Alternatively, the craft (100) could receive a series of changes in position, in which case the craft would calculate the required series of movements of said masses to achieve each individual change in position. In a less sophisticated craft the craft (100) could receive, the actual series of movements of said masses from the off-board source, consisting of the strength and duration of the power applied to each coil (502). The capabilities of the craft to calculate the required series of movements of the masses (501) may be a function of available power. In any case, the coordinated movements of the masses (501) are then carried out by energizing the appropriate coils (502) to effectuate the movement of masses (501) within tubes (504), resulting in the desired movement of the craft (100). The movement of masses (501) could be carried out in parallel or serially, depending on available power. [0048] In the specific embodiment shown in Figure 6, one or more linear actuators 500a are arranged in a hexa-axial configuration, having two linear actuators along the longitudinal axis (i.e., the Z-axis) of the craft, which consists of moving objects (501) that move from one side of the longitudinal axis to the other, creating momentum and forces that could make the craft have some translational movement along the Z-axis. Moreover, several smaller linear actuators (500b) and (500c), oriented orthogonally with respect to each other and the Z-axis, can provide forces to the sides of the craft to change its angular or rotational movement as well as its orientation and trajectory in the direction of the X-axis and Y-axis. Thus, the craft can effect movements of pitch, yaw and roll.

[0049] Another example embodiment of the control system using a combination of linear

actuators (5000) for a spherical craft is shown in the Figure 7. A controlled quick moving of the magnets (501) while creating impulses with the end of their tubes (503) where they integrate into the structure of the floating-object (100), one after another from the center towards the outer shell, could make the sphere rotate around one of its rotational axes. Each moving magnet after colliding the structure of the floating-object (mechanically or magnetically), would bounce back or retracted slowly without creating considerable impulse. For example, by opening the circuit and therefore turning off the magnetic pads or solenoids integrated inside the floating-object and where it get attached to the end of the tube (503) immediately after the impact and instead closing the circuit of the solenoids on the other end of the tube (504) and towards the center of the sphere (101), to position it on the other end of the tube to be ready for another set of accelerations and impulses later. Using such techniques, the spherical craft (100) could also move translationally, or even perform hopping (for example if it is on the very low gravity body of an asteroid). Note that the force here is caused by the fast speed of the magnets and the momentum (mechanically or magnetically and by magnetic torque as described in this disclosure), the torque that they create inside the spherical craft, as opposed to prior art methods which, in the presence of gravity, change the center of the mass of the craft.

[0050] The system and method taught herein, for example, the ones that use a combination of several linear actuators (5000), is capable of creating a momentum to impart movement to the craft (100), for example, making the craft rotate around its rotational axis or creating translational forces that could move the craft translationally. The direction and speed of the craft's translational movement is controlled by controlling the speed of the magnets (501) and their collision to the floating-object (100) as mentioned herein (and by the number of moving magnets along the axes), thereby adjusting the momentum- generated forces in different directions.

[0051] The system and method taught herein provides a method for precisely controlling the movement of a floating-craft (100). It would be realized that the size and scope of the invention are dependent on the size of the craft to be controlled, but that the system should operate identically in craft ranging in size from tiny micro-robots which can be deployed in the human body to large spacecraft operating in space or submersibles operating in a fluid environment. Using this system and method, the movement of magnets (501) can be controlled very accurately to provide very precise control of the movements of the craft. The impulse-based controllable floating-objects or crafts (100) could have external communication capabilities (103) such as RF or optic, etc. with some external base- stations such as the other spacecraft, satellites, or ground-based or planetary based communication dish networks. Figure 8 shows a wireless mesh network (1000) of the impulse-based controllable spacecraft (100) on the micro-gravity of the orbit of the Earth (or other planetary bodies). As shown, spacecraft (100) have communication (for example RF and using Iridium transceivers) with each other as shown as 103a, 103b, and 103f in Figure 8. Additionally, spacecraft 100 may communicate with ground-based stations via an optical connection 103c 103d, and 103e. Such collaborative network of the impulse-based spacecraft (100) could optimize their monitoring, positioning,

communication, or surveillance efforts by optimizing the coverage and also sharing their tasks intelligently in order to optimize the resources of the entire system such as the power, bandwidth, etc. The current state of the art of the cost-effective spacecraft 100 such as the cubesats with extremely limited control system in zero-gravity situation does not allow them to control the direction of their communication antenna to the appropriate directions (other spacecraft, or ground based- stations). The impulse-based control system (5000) described in this disclosure would allow such networking of the floating- spacecraft (1000) with reliable communication capabilities.

Claims

What is claimed is:

1. A method for controlling the movements of a craft in a special environment, said craft being equipped with one or more linear actuators, each of said linear actuators having a tube with one or more moveable masses therein, said method comprising effecting the movement of one or more of said masses within one or more of said tubes to achieve a desired orientation or position of said craft, wherein changes in the orientation or position of said craft are brought about when said movement of said masses imparts a momentum to said craft.

2. The method of claim 1 wherein said linear actuators further comprise one or more magnetic coils to effect the movement of said masses within said tube.

3. The method of claim 1 wherein said linear actuators further comprise a mechanical a mechanical force to effect the movement of said masses within said tube.

4. The method of claim 2 wherein said step of effecting the movement of one or more masses comprises one or more steps of energizing said one or more magnetic coils to achieve a desired speed and final position of said masses.

5. The method of claim 4 wherein said steps of energizing said one or more magnetic coils may be carried out serially or in parallel.

6. The method of claim 1 wherein said craft is equipped with a communication system, further comprising the step of receiving, via said communication system, instructions for changing said orientation of said craft.

7. The method of claim 6 wherein said instructions for changing said orientation of said craft comprise a desired orientation, further comprising the step of calculating movements of one or more of said masses within one or more of said linear actuators to impart momentum to said craft to achieve said desired orientation.

8. The method of claim 6 wherein said instructions for changing said orientation of said craft comprise one or more instructions for movements of one or more of said masses, further comprising the step of effecting said one or more instructions.

9. The method of claim 2 wherein said craft has a power supply for powering said magnetic coils to effect said movement of said one or more masses.

10. The method of claim 9 wherein said power supply is self-sustaining, having the capability recharge via the generation of power or through power harvesting due to movements of said craft.

11. The method of claim 1 wherein said craft is equipped with a set of 6 linear actuators, arranged in a hexa-axial configuration to effect change in pitch, roll and yaw and translation of said craft.

12. The method of claim 11 wherein said craft has a longitudinal axis and further wherein 2 of said linear actuators are aligned along said longitudinal axis and further wherein 2 of said linear actuators are aligned along an axis orthogonal to said longitudinal axis and still further wherein 2 of said linear actuators are aligned along an axis orthogonal to said longitudinal axis and orthogonal to the said other 2 linear actuators.

13. The method of claim 1 wherein said craft is equipped with multiple sets of linear actuators.

14. The method of claim 1 wherein each set of linear actuators has a hexa-axial

configuration.

15. The method of claim 11 where said craft is spherical and is equipped with a single set of linear actuators having a hexa-axial configuration.

16. The method of claim 1 wherein said craft is equipped with a control system and one or more sensors and further comprising the step of, having said control system calculate required changes in the orientation and position of said craft due to requirements imposed by on-board programming and information received from said one or more sensors.

17. The method of claim 16 wherein said further comprising the step of having said control system calculate individual movements of said masses within said tubes to effect said required changes in the orientation and position of said craft.

18. A method for controlling the movements of a craft in a special environment, said craft being equipped with one or more impulse actuators, each of said impulse actuators having a tube with one or more stationary electromagnetic masses positioned therein, said method comprising imposing an electric field against said one or more stationary electromagnetic masses, thereby effecting a torque on said one or more stationary electromagnetic masses which is transferred to said craft via a mechanical coupling.

19. The method of claim 2 wherein said linear actuators further comprise one or more static permanent magnets or electromagnets wrapped around said tube to keep said moveable masses suspended within said tube via a magnetic levitation effect.

20. The method of claim 19 wherein said craft is equipped with a control system, further comprising the step of controlling said one or more static permanent magnets or electromagnets via said control system.