Classifications

• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
  • B64G1/00—Cosmonautic vehicles
  • B64G1/22—Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
  • B64G1/66—Arrangements or adaptations of apparatus or instruments, not otherwise provided for
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B26/00—Optical devices or arrangements for the control of light using movable or deformable optical elements
  • G02B26/08—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light
  • G02B26/0816—Optical devices or arrangements for the control of light using movable or deformable optical elements for controlling the direction of light by means of one or more reflecting elements
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
  • B64G1/00—Cosmonautic vehicles
  • B64G1/22—Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B64—AIRCRAFT; AVIATION; COSMONAUTICS
  • B64G—COSMONAUTICS; VEHICLES OR EQUIPMENT THEREFOR
  • B64G1/00—Cosmonautic vehicles
  • B64G1/22—Parts of, or equipment specially adapted for fitting in or to, cosmonautic vehicles
  • B64G1/24—Guiding or controlling apparatus, e.g. for attitude control
  • B64G1/244—Spacecraft control systems
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B27/00—Optical systems or apparatus not provided for by any of the groups G02B1/00 - G02B26/00, G02B30/00
  • G02B27/64—Imaging systems using optical elements for stabilisation of the lateral and angular position of the image
  • G02B27/644—Imaging systems using optical elements for stabilisation of the lateral and angular position of the image compensating for large deviations, e.g. maintaining a fixed line of sight while a vehicle on which the system is mounted changes course
• • G—PHYSICS
  • G02—OPTICS
  • G02B—OPTICAL ELEMENTS, SYSTEMS OR APPARATUS
  • G02B7/00—Mountings, adjusting means, or light-tight connections, for optical elements
  • G02B7/18—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors
  • G02B7/182—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors for mirrors
  • G02B7/1822—Mountings, adjusting means, or light-tight connections, for optical elements for prisms; for mirrors for mirrors comprising means for aligning the optical axis
  • G02B7/1827—Motorised alignment
• • H—ELECTRICITY
  • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
  • H02K—DYNAMO-ELECTRIC MACHINES
  • H02K41/00—Propulsion systems in which a rigid body is moved along a path due to dynamo-electric interaction between the body and a magnetic field travelling along the path
  • H02K41/02—Linear motors; Sectional motors
  • H02K41/035—DC motors; Unipolar motors
  • H02K41/0352—Unipolar motors
  • H02K41/0354—Lorentz force motors, e.g. voice coil motors

Definitions

• FSM Fast moving steering mirrors
• beam steering mirrors are commonly used in high-performance electro-optical sensors or laser systems for pointing laser beams or stabilizing the line of sight of an optical sensor
• the FSM is large enough (e.g., about 2 inch to about 20 inch aperture mirror) that motion of the mirror must be implemented in a way that its exported reaction loads (e.g., "kickback" torque and/or force due to acceleration of the mirror) are compensated for by a mass moving in the opposite direction of the mirror.
• the reaction mass must be driven in such a way that the phase error with the mirror is extremely low to ensure that the exported load is minimized. This is often accomplished by actively driving the reaction mass with a dedicated separate set of actuators and tilt position sensors.
• FIG. 1 is a schematic diagram of a two axis reaction compensated steerab!e platform device in accordance with an example of the present disclosure.
• FIG. 2 illustrates tilting of the two axis reaction compensated steerabie platform device of FIG. 1.
• FIG. 3A is a schematic diagram top view of a two axis reaction compensated steerabie platform device in accordance with an example of the present disclosure.
• FIG. 3B is a schematic diagram top view of a two axis reaction compensated steerabie platform device in accordance with another example of the present disclosure.
• FIG. 4 is a schematic diagram of a three axis reaction compensated steerabie platform device in accordance with an example of the present disclosure.
• FIG. 5 is a schematic diagram top view of a three axis reaction compensated steerabie platform device in accordance with an example of the present disclosure.
• the term “substantially” refers to the complete or nearly complete extent or degree of an action, characteristic, property, state, structure, item, or result.
• an object that is “substantially” enclosed would mean that the object is either completely enclosed or nearly completely enclosed.
• the exact allowable degree of deviation from absolute completeness may in some cases depend on the specific context. However, generally speaking the nearness of completion will be so as to have the same overall result as if absolute and total completion were obtained.
• adjacent refers to the proximity of two structures or elements. Particularly, elements that are identified as being “adjacent” may be either abutting or connected. Such elements may also be near or close to each other without necessarily contacting each other. The exact degree of proximity may in some cases depend on the specific context.
• a reaction compensated steerable platform device can measure and directly compensate for the exported loads generated by movement of a reaction mass, thereby accommodating differences in balance and alignment between a steerable platform and a reaction mass.
• the reaction compensated steerable platform device can include a base, a steerable platform movably coupled to the base, and a reaction mass movably coupled to the base.
• the reaction compensated steerable platform device can also include a primary actuator coupled to the steerable platform and the base to cause movement of the steerable platform.
• the reaction compensated steerable platform device can further include a secondary actuator coupled to the reaction mass and the base to cause movement of the reaction mass.
• the reaction compensated steerabie platform device can also include a load sensor configured to provide feedback for actuation of the secondary actuator, such that the reaction mass moves to compensate for a load induced on a support structure by the movement of the steerabie platform.
• a reaction compensated steerabie platform system can include a support structure and a reaction compensated steerabie platform.
• the reaction compensated steerabie platform can include a base coupled to the support structure, a steerabie platform movably coupled to the base, and a reaction mass movably coupled to the base.
• the reaction compensated steerabie platform can also include a primary actuator coupled to the steerabie platform and the base to cause movement of the steerabie platform.
• the reaction compensated steerabie platform can further include a secondary actuator coupled to the reaction mass and the base to cause movement of the reaction mass, in addition, the reaction compensated steerabie platform can include a load sensor configured to provide feedback for actuation of the secondary actuator, such that the reaction mass moves to compensate for a load induced on the support structure by the movement of the steerabie platform.
• FIG. 1 illustrates a schematic diagram of a reaction compensated steerabie platform device 100 in accordance with another example of the present disclosure.
• the device 00 can include a base 110 that can support various components of the reaction compensated steerabie platform device 100, as described herein.
• the device 100 can also include a steerabie platform 120 movably coupled to the base 110, such as by a pivot connector assembly, which can include one or more pivot connectors 140.
• the device 100 can include one or more primary actuators 130a, 130b (e.g. , force actuators) to cause movement of the steerabie platform 120.
• the loads generated by movement of the steerabie platform can be "exported" from a steerabie platform device to a support structure for the device, which may become evident at higher speeds or frequencies.
• a steerabie platform device may form a part of a FS , which is mounted to a support structure of a satellite. Loads from the FSM as generated by movement of the steerabie platform can be exported to the support structure of the satellite, which can interfere with other components and systems of the satellite, such as by exciting structural vibration modes and causing unwanted structural vibrations.
• the device 100 can also include a reaction mass 50 movably coupled to the base 110 to provide cancellation of loads (e.g., torques and/or forces) generated by movement of the steerabie platform 120.
• the reaction mass 150 can be movably coupled to the base 110 by a connector assembly, which can include one or more connectors 142.
• the device 100 can further include one or more secondary actuators 132a, 132b to cause movement of the reaction mass 150.
• the connectors 140, 142 can include any suitable type of connector or mechanism for providing pivotal or rotational movement, such as a flexible connector (e.g., a pivot flexure), a bearing connector (e.g. , ball bearings), a bushing connector, etc.
• a flexible connector e.g., a pivot flexure
• a bearing connector e.g. , ball bearings
• bushing connector e.g., a bushing connector, etc.
• connectors referred to herein may include any suitable type of pivotal or rotational connector known in the art.
• the primary actuators 130a, 130b can be coupled to the base 110 and the steerabie platform 120, such that actuation of the primary actuators 30a, 130b causes the steerabie platform 120 to move.
• the secondary actuators 132a, 132b can be coupled to the base 110 and the reaction mass 150, such that actuation of the secondary actuators 132a, 132b causes the reaction mass 150 to move.
• Such a configuration is referred to generally as an "active" reaction mass load cancellation configuration due to the secondary actuators 32a, 32b actively causing the reaction mass 150 to move in opposition to the steerabie platform 120, which is caused to move by the primary actuators 130a, 130b.
• the primary actuators 130a, 130b and secondary actuators 32a, 132b can comprise voice coil or similar force actuators, which can extend/retract to cause movement of the steerabie platform 120 and the reaction mass 150, respectively.
• FIG. 1 shows primary actuators 130a, 130b on opposite sides of the connector 140.
• One primary actuator 130a can extend (i.e., "push") and the other primary actuator 130b can retract (i.e., "pull”) to cause rotation of the steerable platform 120, such as about a y-axis, as shown in FIG. 2.
• the secondary actuators 132a, 132b are also shown on opposite sides of the connector 42.
• One secondary actuator 132a can extend (i.e., "push") and the other secondary actuator 132b can retract (i.e., "pull") to cause rotation of the reaction mass 150, such as about a y-axis, as shown in FIG. 2.
• a similar arrangement of primary and secondary actuators and connectors can be included to facilitate rotation of the steerable 120 platform and the reaction mass 150 about another axis, such as the x-axis.
• primary and secondary actuators and connectors can be configured to provide for tilting of the steerable platform 120 and the reaction mass 150 in two dimensions or degrees of freedom.
• the device 100 can include one or more position sensors 160a, 180b that can be mounted on the base 110 and/or the steerable platform 120 and used to monitor the position (e.g., the angular position) of the steerable platform 120 relative to the base 110.
• the device 100 can include one or more load sensors 162a, 162b (such as a force and/or torque sensor) configured to provide feedback for actuation of the secondary actuators 32a, 132b.
• the load sensors 162a, 162b can be located or disposed where the base 110 is coupled to a support structure (indicated by the fixed coupling at 112) for the device 00 to which the base 110 is coupled, such as coupled between the base 110 and the support structure.
• the device 00 coupled to a support structure can form a reaction compensated steerable platform system in accordance with the present disclosure.
• the primary actuators 30a, 130b can be controlled by a servo or control loop 170 using position feedback from the steerable platform 120 (e.g., the position sensors 160a, 160b between the steerable platform 120 and the base 110).
• the secondary actuators 132a, 132b can be controlled by a servo or control loop 172 using force and/or torque feedback from the load sensors 162a, 162b at the base mount (indicated at 112, e.g., between the base 110 and a support structure in support of the device 00).
• the secondary actuators 132a, 132b operate in the control loop 172, which can utilize force and/or torque feedback of the base 110 (which includes the base and everything supported by the base), in order to directly measure loads induced by the movement of the steerabie platform and move the reaction mass 150 to offset or cancel the loads.
• the load sensors 162a, 162b can provide force and/or torque feedback for actuation of the secondary actuators 132a, 132b to cause the reaction mass 150 to move in a manner that compensates for loads induced by the movement of the steerabie platform 120,
• the reaction mass 50 can be independently controlled by the secondary actuators 132a, 132b to directly cancel or eliminate the exported loads.
• Using feedback from the load sensors 162a, 162b therefore allows the reaction mass 50 to move in a manner that actively offsets and cancels actual loads generated by the movement of the steerabie platform 120, instead of merely attempting to offset torque based on movement and position.
• the device 100 can accommodate differences in balance and alignment between the steerabie platform 120 and the reaction mass 150 that would otherwise go unaccounted for in a typical active reaction compensated steering mirror.
• two control loops can be utilized to control operation of the primary actuators.
• a two axis device can include two control loops to control operation of the secondary actuators 132a, 132b.
• one control loop for each axis using load feedback at the base mounting location 112 with a supporting structure in one aspect, can use information from one or more acceierometers located at a desired vibration sensitive interface or location.
• a servo loop can be used to control actuation of the primary actuators 130a, 130b for movement of the steerable platform 120 in each degree of freedom.
• a servo loop can be used to control actuation of the secondary actuators 132a, 132b for movement of the reaction mass 150 in each degree of freedom, in one aspect, the control or servo loop for actuation of the primary and/or secondary actuators can use external feedback from an optical sensor (e.g. , a quad cell, a photopot, etc.) measuring or sensing the steerable platform 120 and/or the reaction mass 150.
• an optical sensor e.g. , a quad cell, a photopot, etc.
• a reaction compensated steerable platform device will include three or four primary actuators to facilitate rotation or angular movement of a steerable platform about two orthogonal axes.
• three primary actuators 230a-c can be utilized and angularly spaced apart from one another at suitable angles, such as 120 degrees, although the primary actuators can be disposed in any angular configuration, in another example, illustrated in FIG. 3B, four primary actuators 330a-d can be utilized, such as two primary actuators per rotational degree of freedom.
• the steerable platforms have been omitted for clarity to illustrate components that would otherwise be obscured.
• the connectors 140 can constrain the position of the steerable platform 120 in a flexible manner, enabling the steerable platform 120 to be controlled while still allowing for freedom of motion in one or more degrees of freedom.
• the connectors 140 can have a certain degree of mechanical flexibility in combination with a degree of mechanical rigidity.
• Any suitable number of connectors 140 can be utilized in any suitable configuration to facilitate movement of the steerable platform in one or more degrees of freedom, such as rotational degrees of freedom about two orthogonal axes.
• an individual connector 240 can be configured to provide movement in two degrees of freedom (FIGS. 3A and 3B), such as rotation about two axes, in another example, one or more connectors can be utilized to facilitate movement in a single rotational degree of freedom.
• an individual connector e.g., a cross-blade flexure pivot or a pivot flex bearing
• a cross-blade flexure pivot or a pivot flex bearing can be configured to provide movement in only a single degree of freedom, such as rotation about an axis.
• three connectors can be utilized and angularly spaced apart from one another at suitable angles, such as 120 degrees, although the connectors can be disposed in any angular configuration, in this case, an individual connector can be configured to provide movement in two degrees of freedom (e.g., two rotational) or three degrees of freedom (e.g., two rotational and one translational), as discussed further below.
• the connectors 140 and actuators 130a, 130b can therefore be utilized to adjust the tilt angle of the steerabie platform 120 in the x-z plane and/or the y- z plane. Tilting in the x-z plane and the y-z plane may be referred to as a rotation about the y-axis and a rotation about the x-axis, respectively.
• the reaction mass 150 can be movably coupled to the base 110 (i.e., by suitable connectors 42) in a manner similar to the steerabie platform 20 to provide for movement in similar degrees of freedom, such that the reaction mass 50 can move opposite the steerabie platform 120 to compensate for loads induced by movement of the steerabie platform 120.
• any suitable number of position sensors 160a, 160b can be utilized in any suitable configuration to determine position of the steerabie platform 120 in one or more degrees of freedom, such as rotational degrees of freedom about two orthogonal axes.
• three position sensors 260a-c can be utilized and angularly spaced apart from one another at suitable angles, such as 120 degrees, although the position sensors can be disposed in any angular configuration.
• four position sensors 360a-d can be utilized, such as two position sensors per rotational degree of freedom.
• the position sensors disclosed herein can be any suitable type of position sensor, such as an interferometric position sensor, an inductive position sensor, etc.
• the position sensors can be configured to determine the position of the steerab!e platform in one or more dimensions. Position sensors with a large dynamic range are desirable since such sensors can provide precise position information over a large range of distances.
• load sensors 182a, 182b can be utilized in any suitable configuration to determine loads in one or more degrees of freedom, such as rotational degrees of freedom about two orthogonal axes.
• three load sensors 262a-c can be utilized and angularly spaced apart from one another at suitable angles, such as 120 degrees, although the load sensors can be disposed in any angular configuration, in another example, illustrated in FIG. 3B, four load 362a-d sensors can be utilized, such as two load sensors per rotational degree of freedom.
• a load sensor will be referred to generally as a sensor that can measure force and/or torque (e.g. , a load ceil), which can be measured or sensed in any suitable manner.
• a load sensor can measure or sense one or more quantities that may be used to derive a force or a torque, such as utilizing an accelerometer. in a specific example, a load sensor can measure force in order to derive the torque.
• the device 100 can include any suitable number of primary actuators 130a, 130b and secondary actuators 132a, 32b, as described herein.
• three secondary actuators can be utilized and angularly spaced apart from one another at suitable angles, such as 120 degrees, although the secondary actuators can be disposed in any angular configuration.
• four secondary actuators can be utilized, such as two secondary actuators per rotational degree of freedom.
• the reaction compensated steerabie platform device 100 is an example of a two axis device (e.g., rotation about two orthogonal axes).
• the actuators disclosed herein can be any suitable type of actuator, such as a voice coil actuator, a Lorenz force actuator, a current-mode actuator, an eiectrostrictive actuator, a piezoelectric actuator, a pneumatic actuator, a hydraulic actuator, an electromechanical screw-jack actuator, etc. in one example, a moveable support member fabricated using a spring to provide a repulsive force, and a solenoid to provide an attractive force can be used.
• an optical assembly (not shown) will be mounted to the steerable platform 120 to provide a steerable mirror (e.g., FSM).
• the steerable mirror can have a reflective surface, such as in the shape of an annulus as can be found in telescopes commonly referred to as Cassegrain telescopes.
• the reaction compensated steerable platform device 00 can be utilized in other applications as well, such as air or space borne telescopes, laser systems, laser radar systems, and the like. The technology has been found particularly effective as a platform to support a mirror for line-of- sight scanning and stabilization or other precision pointing uses.
• the steerable platform 120 and/or the base 110 can be configured to provide a rigid support for an optical assembly.
• FIG. 4 illustrates a schematic diagram of a reaction compensated steerable platform device 400 in accordance with another example of the present disclosure.
• the device 400 is similar to the device 100 in many respects, such as utilizing an active reaction mass configuration with a secondary actuator 432a, 432b for a reaction mass 450 controlled by feedback from a load sensor 462a, 462b between a base 410 and a supporting structure (at 412).
• connectors 440a, 440b of a steerable platform 420 to the base 410 and connectors 442a, 442b of the reaction mass 450 to the base 410 are configured to facilitate relative movement in a transiational degree of freedom, in addition to one or more rotational degrees of freedom.
• the primary actuators 430a, 430b and the secondary actuators 432a, 432b can be configured to "piston" (e.g., a linear stroke) to provide movement of the steerable platform 420 and the reaction mass 450 in a transiational degree of freedom, in addition to one or more rotational degrees of freedom, thus providing a three axis device.
• position sensors 460a, 460b of the device 400 can be configured to sense position in the three degrees of freedom (two rotational and one transiational) to provide position feedback for the primary actuators 430a, 430b.
• the piston action of the actuators can cause movement of the steerable platform 420 (e.g., to provide pivoting about a virtual pivot point) that results in reaction force as well as torque that may be exported from the device 400.
• the load sensors 462a, 462b of the device 400 can be configured to sense loads in the three degrees of freedom (two rotational and one transiational) to provide load feedback for the secondary actuators 432a, 432b to facilitate cancelling or offsetting reaction loads in three degrees of freedom.
• the connectors can comprise a C-flexure, a U-flexure, a J-flexure, or the like.
• the connector in this example can be formed in the shape of the letter "C", "IT, or "J" to provide flexibility in the z-direction.
• Such connectors can act as a constraint on the position of the steerable platform 420 or the reaction mass 450, yet can be flexible in the z-direction, enabling the supported structure to translate in the z-direction.
• the connectors can also be pivotal or rotational about one or more axes of rotation, such as about the x-axis and/or y-axis.
• a connector can include any suitable device or mechanism to provide movement in a transiational degree of freedom, such as a linkage mechanism or a linear bearing.
• a three axis device 500 can have actuators 530a-c (secondary actuators obscured from view), position sensors 580a-c, load sensors 562a-c, and connectors 540a-c included in any suitable quantity and configuration, such as having three of each type of component disposed at 120 degrees from one another, as illustrated in FIG. 5.
• a method for facilitating compensation of a reaction in a steerable platform device can include obtaining a steerable platform device, having a base, a steerable platform movably coupled to the base, a reaction mass movably coupled to the base, a primary actuator coupled to the steerable platform and the base to cause movement of the steerable platform, and a secondary actuator coupled to the reaction mass and the base to cause movement of the reaction mass. Additionally, the method can include facilitating sensing of a load induced on a support structure by the movement of the steerable platform to provide feedback for actuation of the secondary actuator, such that the reaction mass moves to compensate for the load. It is noted that no specific order is required in this method, though generally in one
• these method steps can be carried out sequentially.
• facilitating sensing of a load can comprise obtaining a load sensor.
• the load sensor can comprise at least one of a load cell and an acceieromefer.
• the load sensor can be coupleabie between the base and a support structure.

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• 2016
  • 2016-02-22 US US15/050,359 patent/US10197792B2/en active Active
  • 2016-12-22 WO PCT/US2016/068345 patent/WO2017146812A1/en active Application Filing
  • 2016-12-22 EP EP16828843.9A patent/EP3420399A1/en not_active Withdrawn
  • 2016-12-22 JP JP2018544124A patent/JP6641496B2/ja not_active Expired - Fee Related
• 2018
  • 2018-08-15 IL IL261177A patent/IL261177B/en active IP Right Grant

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