Magnetically actuated exciter device with impact hammer function.

Abstract

The exciter device is configured to apply both a vibration force and an impact force to the device under test. A first end of the piston is coupleable to the device under test and a second end of the piston is aligned with the position of the impact hammer tip. The impact hammer tip and the electromagnet are both coupled to a moveable housing disposed about the piston. The exciter device applies a vibration force to the device under test when an alternating magnetic field is applied by the electromagnet to the permanent magnet that induces linear reciprocating motion of the moveable housing relative to the piston. The exciter device applies an impact force to the device under test when a magnetic field is applied by the electromagnet to the permanent magnet that induces linear motion of the moveable housing sufficient to bring the impact hammer into contact with the second end of the piston.

Description

[Technical field]

[0001] Background technology The present invention relates generally to electromagnetic devices, and more particularly to a structure for manufacturing a magnetically actuated shaker device. Summary of the Invention [Means for solving the problem]

[0002] In one embodiment, the present invention provides an exciter apparatus including a piston, a permanent ring magnet, a moveable housing, an impact hammer, and an electromagnet. A first end of the piston is coupleable to a device under test and a second end of the piston is aligned with the position of the impact hammer. The permanent ring magnet is fixedly coupled to the piston and the electromagnet is coupled to the moveable housing such that a magnetic field generated by the electromagnet impinges on the permanent ring magnet and causes movement of the moveable housing relative to the piston. The exciter apparatus applies a vibration force to the device under test when an alternating magnetic field is applied by the electromagnet to the permanent magnet causing linear reciprocating motion of the moveable housing relative to the piston. The exciter apparatus applies an impact force to the device under test when a magnetic field is applied by the electromagnet to the permanent magnet causing linear motion of the moveable housing sufficient to bring the impact hammer into contact with the second end of the piston.

[0003] In some implementations, the present invention provides a force-responsive testing system including an exciter device and an electronic controller. The electronic controller is communicatively coupled to the exciter device and configured to generate control signals for causing the exciter device to selectively apply vibration and impact forces. In some implementations, the electronic controller is configured to generate the control signals by generating a current that is applied to a coil of an electromagnet.

[0004] In another embodiment, the present invention provides a method for applying a force to a device under test by operating an exciter apparatus to apply a vibrational force to the device under test and operating the exciter apparatus to apply an impact force to the device under test. The vibrational force is applied by an electronic controller by sending a first electrical signal input to the exciter apparatus that causes an electromagnet to generate an alternating magnetic field applied to a permanent ring magnet that causes linear reciprocating motion of the moveable housing relative to a piston. The impact force is applied by sending a second electrical signal input to the exciter apparatus that causes an electromagnet to generate a magnetic field applied to a permanent ring magnet that causes linear motion of the moveable housing sufficient to drive an impact hammer tip of the moveable housing into contact with a second end of the piston.

[0005] In some embodiments, the present invention provides a method of applying an impact force to a device under test by sending an electrical signal input to an electromagnet of an exciter device, causing the electromagnet to generate a magnetic field applied to the permanent ring magnet that causes a linear motion of the moveable housing sufficient to drive a first component coupled to the piston into a second component coupled to the housing. In some embodiments, the first component is a second end of the piston and the second component is an impact hammer tip attached to the moveable housing positioned to align with the second end of the piston. In other implementations, the first component may include an impact hammer tip coupled to the second end of the piston and the second component may be a surface of a support plate of the moveable housing. In other implementations, the first component may be a permanent ring magnet coupled to the piston and the second component may be another component of the moveable housing, and when a magnetic field is applied to the electromagnet, the impact force is generated by the magnet of the piston colliding with the other component of the moveable housing.

[0006] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings. [Brief description of the drawings]

[0007] [Figure 1A] 1 is a cross-sectional view of a movable housing of an exciter device (eg, a mobile exciter device). [Figure 1B] FIG. 1B is a perspective view of the exciter device of FIG. 1A. [Figure 2A] FIG. 1B is a cross-sectional view of the exciter device of FIG. 1A with a selectively attachable impact hammer attachment component. [Figure 2B] FIG. 2B is a perspective view of the exciter device of FIG. 2A. [Diagram 3] FIG. 4 is a block diagram for a control system for the exciter device of FIGS. 1A-2B. [Figure 4] 4 is a graph of the control signals applied by the control system of FIG. 3 to the exciter apparatus of FIGS. 1A and 1B to apply a vibration force to a structure / device under test. [Diagram 5] 4 is a graph of the control signals applied by the control system of FIG. 3 to the exciter device of FIGS. 2A and 2B to apply an impact force to a structure / device under test. [Figure 6] 4 is a flow chart of a method for controllably applying forces to a structure / device under test using the exciter apparatus of FIGS. 1A-2B. [Figure 7] FIG. 3 is a cross-sectional view of the magnetic axial and radial suspension system of the exciter device of FIGS. 1A-2B. [Figure 8A] FIG. 2 is a perspective view of the cylindrical body of the exciter device. [Figure 8B] FIG. 2 is a perspective view of a bobbin of the exciter device. [Figure 8C] FIG. 8C is a perspective view of the bobbin assembly of FIG. 8B positioned within the cylindrical body of FIG. 8A during assembly. [Figure 8D] FIG. 2 is a perspective view of a mode indicator of the exciter device. [Figure 8E] FIG. 2 is a perspective view of a table assembly of the exciter apparatus. [Figure 8F] FIG. 2 is a perspective view of a lower support plate assembly of the exciter apparatus. [Figure 8G]FIG. 1 is a perspective view of a radial guide bushing (i.e., neoprene O-ring) of the exciter device. [Figure 8H] FIG. 1 is a perspective view of the housing of the impact hammer attachment component of the exciter device. [Figure 8I] FIG. 1 is a perspective view of the hammer tip and set screw of the impact hammer attachment component of the exciter device. [Figure 8J] FIG. 8B is a perspective view of a key-lock tool for selectively coupling and decoupling the upper support plate, the lower support plate, and / or the impact hammer attachment components to the cylindrical body of FIG. 8A. [Figure 9] 1B is a flowchart of a method for fabricating the exciter device of FIG. 1A using 3D printing. [Figure 10] 1B is a flowchart of an alternative method for assembling the exciter device of FIG. 1A by 3D printing components directly onto other components. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Before describing any embodiments of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components set forth in the following description or illustrated in the following drawings. The invention is capable of other embodiments and of being practiced or carried out in various ways.

[0009] Modal testing is a process for measuring structural frequency response functions (FRFs). The user is responsible for selecting the correct sensors, channel couplings, frequency ranges, etc., to obtain the system frequency response function with high accuracy. Various embodiments of the present invention recognize that an impact hammer, a single shaker, or multiple shakers can be used to excite a device under test (DUT) or structure under test (SUT). However, conventional impact hammers often cannot impart enough energy to obtain an appropriate response signal in the frequency range of interest, and the direction of the applied force is also difficult to control. Furthermore, integrated shaker devices are limited to the range of frequencies that the device can provide to the DUT.

[0010] The present invention provides multiple excitation modes for high-precision measurements, precise exciter location and orientation by providing an exciter apparatus including an impact hammer and a non-contact magnetic axial suspension, which eliminates uncertainties due to equipment changes. As described in more detail below, in some implementations, the magnetic axial suspension is implemented with a zero-clearance low-friction radial suspension. Furthermore, the exciter apparatus provides in-line excitation for impact and / or continuous excitation (e.g., vibration) at points with limited access over a wide frequency range (e.g., 10-10,000 Hz), for example, by selectively switching between these two excitation modes and reassembling the frequency response function (FRF) measurements taking into account the quality achieved at the different frequency ranges.

[0011] Various embodiments of the present disclosure recognize that challenges exist in limiting component movement when utilizing a magnetic-based system to induce vibration. Some mechanisms for limiting movement of components of an exciter device (e.g., vibration exciter or "shaker device") during vibration may include, for example, springs, cushions, or brackets that physically block the components from moving beyond a certain displacement. However, embodiments of the present invention provide a device that utilizes a first permanent ring magnet fixed to a non-magnetic table and positioned as the primary driving and inductive component of the exciter device, and at least one instance of a second permanent ring magnet positioned to generate a repulsive force with the first permanent ring magnet to provide a magnetic axial suspension for the exciter device. The second permanent ring magnet of the magnetic axial suspension eliminates the need for various mechanisms for limiting component movement, allowing the exciter device to be easily miniaturized and reducing manufacturing costs. In some implementations, the non-contact magnetic axial suspension involves a zero-clearance (e.g., "self-aligning") low-friction radial suspension that provides a ring-shaped contact interface between a table / piston fixed to the device under test and a moving body.

[0012] Embodiments of the present invention recognize that various challenges exist in the manufacture and assembly of structural devices using conventional machining methods. For example, the various material properties of solid structures cannot be achieved by conventional machining methods. Furthermore, conventional machining methods are limited to certain shapes / geometry, such as angled channels (e.g., angled through holes for wire routing, notches, etc.), because the shape / geometry cannot be achieved by conventional machining methods or is so difficult and / or expensive to manufacture that it is impractical. Also, embodiments of the present invention recognize that conventional manufacturing methods include tolerance and additional assembly issues.

[0013] Embodiments of the present invention enable additive manufacturing of fully functional shaker devices, including shapes and geometries that are difficult or impossible to machine using traditional methods. Additionally, the shaker device and corresponding forces are scalable as components of the shaker device can be additively manufactured with the exception of the coil, permanent magnets, and radial guide bushings, resulting in a reduction in the overall weight of the device. It also provides customized components (e.g., pistons, bases, etc.) that can be designed for a variety of complex surfaces, threaded inserts, and / or areas of limited space. Additionally, additive manufacturing of the shaker device allows multiple components of the device to be formed as one complex part, thereby avoiding assembly and tolerance issues and reducing costs associated with waste materials over traditional subtractive manufacturing methods. In some implementations, the use of additive manufacturing allows for alternative distribution modalities. For example, in some implementations, rather than a manufacturer manufacturing a physical device, a design file can instead be tailored to a specific customer (e.g., rescaling components for a specific application) and digitally transferred to the customer who manufactures the vibration exciter device using a 3D printer, thereby avoiding the wait times associated with traditional manufacturing and delivery.

[0014] Additive manufacturing techniques can also be used to achieve "differently tuned" vibration exciters using the same internal components (e.g., coils, magnets, O-rings, etc., as described in detail below). Slight scaling adjustments to the axial dimensions of the vibration exciter before printing can be used to tune the spacing of the same suspension magnets and table magnets, thus decreasing the axial dimensions increases the axial repulsion, increases the stiffness of the vibration exciter, shifts the natural resonance to higher frequencies, and makes the vibration exciter less susceptible to damage at low frequency operation. Conversely, increasing the scale of the axial dimensions of the vibration exciter decreases the axial repulsion, and therefore the axial stiffness, resulting in more force output in the low frequency range.

[0015] 1A and 1B show an example of an exciter apparatus 100 for controllably applying a vibration force to a device / structure under test. As shown in FIG. 1B, the exciter apparatus 100 (e.g., shaker apparatus) includes a movable housing 110 having a lower support plate 112, an upper support plate 114, a cylindrical body 116, and a mode indicator 118. As shown in FIG. 1A, the upper support plate 114 and the cylindrical body 116 are formed with oppositely interlocking helical structures such that the upper support plate 114 is selectively connectable to the cylindrical body 116 by a threading action at a first end of the cylindrical body 116. Similarly, the lower support plate 112 and the cylindrical body 116 are also formed with oppositely interlocking helical structures such that the lower support plate 112 is selectively connectable to the cylindrical body 116 by a threading action at a second end of the cylindrical body 116.

[0016] The movable housing 110 is positioned to partially surround the non-magnetic table 120 (e.g., a piston). The lower support plate 112 and the upper support plate 114 each include an opening positioned to allow a respective end of the non-magnetic table 120 to extend from the movable housing 110. Additionally, a mode indicator 118 is coupled to the cylindrical body 116. Additionally, a first end of each end of the non-magnetic table 120 is coupled to a base 170 that is coupleable to a device / structure under test. The base 170 holds the non-magnetic table stationary relative to the device / structure under test, and movement of the movable housing 110 relative to the non-magnetic table 120 imparts a force to the device / structure under test, as described in more detail below.

[0017] The radial guide bushings 140 are disposed in both openings of the movable housing 110. The radial guide bushings 140 are coupled to the movable housing 110. For example, a first radial guide bushing 140 is coupled to the lower support plate 112 of the movable housing 110 proximate a first end of the non-magnetic table 120. Similarly, a second radial guide bushing is coupled to the upper support plate 114 proximate a second end of the non-magnetic table 120. The radial guide bushings 140 each include a circular opening that surrounds the non-magnetic table 120 and guides the movement of the movable housing 110 relative to the non-magnetic table 120. For example, the radial guide bushings 140 align the movement of the movable housing 110 relative to the non-magnetic table 120. In some implementations, the radial guide bushing 140 is formed of a neoprene material (e.g., a neoprene O-ring) and remains in contact with the non-magnetic table 120 during operation of the exciter apparatus 100 as the movable housing 110 moves relative to the non-magnetic table 120.

[0018] The radial guide bushing 140 acts as a radial suspension for the exciter apparatus 100 and is constructed of a flexible material with a low coefficient of friction between the table / piston 120 and the radial guide bushing 140. In some implementations, the compressible material of the radial guide bushing 140 causes the exciter apparatus 100 to eliminate clearance between the radial guide bushing 140 and the table / piston 120 when the exciter apparatus 100 is assembled. For example, in some implementations, the final assembly of the exciter apparatus 100 causes the radial guide bushing 140 to compress axially between the axial suspension ring magnet 150 and the support plate 112 / 114. This axial compression causes expansion of the radial guide bushing 140 in the radial direction, closing any clearance that may exist between the radial guide bushing 140 and the table / piston 120.

[0019] Additionally, the axial magnetic force applied to the axial suspension ring magnet 150 further contributes to an axial compressive force applied to the radial guide bushing 140 at both the top and bottom of the exciter apparatus 100. This provides a radial suspension that is "self-adjusting" in that as the permanent ring magnet 130 of the table / piston 120 approaches the axial suspension ring magnet 150 at either end of the exciter apparatus 100, the axial suspension ring magnet 150 provides an opposing magnetic force such that it presses further against the radial guide bushing 140. Thus, as the moveable housing 110 approaches either end of the table / piston 120, the corresponding radial guide bushing 140 expands further in the radial direction, increasing the degree of radial stiffness between the moveable housing 110 and the table / piston 120. This increased stiffness of the radial suspension may further limit rocking of the table / piston 120 and, in some implementations, provide a "zero play" radial condition even at higher load operation and / or compensate for wear at the contact interface between the radial guide bushing 140 and the table / piston 120.

[0020] In some implementations, the radial guide bushing 140 is further configured to provide a limited surface area contact (e.g., an idealized "line contact") between the radial guide bushing 140 and the table / piston 120. The reduced contact area also reduces axial friction. In some implementations, the radial guide bushing 140 is fabricated from a neoprene material to provide a balance between radial flexibility and an axial coefficient of friction. In some implementations, a silicone lubricant may be added between the table / piston 120 and the radial guide bushing 140 to further reduce friction between the parts.

[0021] An axial suspension ring magnet 150 is also disposed in an opening in the lower support plate 112, and a second axial suspension ring magnet is similarly disposed in an opening in the upper support plate 114. In some implementations, the axial suspension ring magnet 150 is coupled to the lower support plate 112 of the movable housing 110 and surrounds the non-magnetic table 120. As described in more detail below, the permanent ring magnet 130 is coupled to the non-magnetic table 120 to drive the movement of the movable housing 110, and the axial suspension ring magnet 150 damps the movement of the movable housing 110 relative to the non-magnetic table 120 by providing an opposing magnetic force when the permanent ring magnet 130 approaches the axial suspension ring magnet 150. The axial suspension ring magnet 150 also limits the distance the non-magnetic table 120 extends from the movable housing 110, preventing the portion of the non-magnetic table 120 to which the permanent ring magnet 130 is attached from extending outside the movable housing 110. For example, the poles of the axial suspension ring magnet 150 are oriented to face the same poles of the permanent ring magnet 130 fixed to the non-magnetic table 120 to create a repulsive force that suspends the non-magnetic table 120 and prevents the non-magnetic table 120 from being ejected from the movable housing 110. In some implementations, the axial suspension ring magnet 150 and the permanent ring magnet 130 are both permanent ring magnets constructed of neodymium material.

[0022] The non-magnetic bobbin 160 is disposed within the movable housing 110 and at least partially surrounds the non-magnetic table 120 as well as the permanent ring magnet 130 attached thereto. The non-magnetic bobbin 160 is coupled to the cylindrical body 116 of the movable housing 110. A coil 165 is formed around the non-magnetic bobbin 160. In the example of FIG. 1A, the coil 165 includes at least two opposing windings. The type and shape of the windings of the coil 165 are configured to generate comparable parameters (e.g., inductance, Q factor, insulation strength, and the strength of a desired magnetic field, etc.) for the opposing windings. The coil 165 is formed from a conductive material (e.g., copper wire) and, when a current is controllably applied to the coil 165 (as described in more detail below), the coil 165 operates as an electromagnet that provides a controllable magnetic field. A controllable magnetic field is applied to the permanent ring magnet 130 to selectively induce movement of the moveable housing 110 relative to the permanent ring magnet 130 (and the non-magnetic table 120 to which the permanent ring magnet 130 is coupled) by controllably applying a magnetic field that attracts and repels the permanent ring magnet 130. Thus, the moveable housing 110 is controllably moved up and down relative to the non-magnetic table 120 by controlling the current applied to the coil 165.

[0023] In the example of FIG. 1A , the mode indicator 118 is disposed between the cylindrical body 116 and the upper support plate 114. In some implementations, the mode indicator 118 is a plastic ring body having one or more light emitting diodes disposed therein to controllably illuminate the mode indicator 118. In some implementations, the mode indicator 118 is coupled to the cylindrical body 116 of the movable housing 110. In other implementations, the mode indicator 118 is coupled to the upper support plate 114 of the movable housing 110. In still other implementations, the mode indicator 118 is a separate component that is held in place between the upper support plate 114 and the cylindrical body 116 of the movable housing 110 when the upper support plate 114 is selectively coupled to the cylindrical body 116 by a threaded action.

[0024] In the example of FIG. 1A, the mode indicator 118 indicates the operating mode of the exciter device. The mode indicator 118 may include one or more light emitting diodes (LEDs), which may change color to indicate the operating mode. Additionally, the mode indicator 118 may continuously light up or flash (e.g., power off and on) while the exciter device is operating. In the example of FIG. 1A, the mode indicator 118 may be controlled based on an electrical signal input (e.g., a control signal of a controller, a current in the coil 165, etc.) received by the exciter device.

[0025] As described in further detail below, the lower support plate 112, the upper support plate 114, the cylindrical body 116, and / or the mode indicator 118 of the moveable housing 110 may be manufactured by additive manufacturing (e.g., three-dimensional (3D) printing). For example, the lower support plate 112 and the upper support plate 114 may be constructed of composite carbon fiber polylactic acid (PLA), the cylindrical body 116 may be constructed of composite iron PLA, and the mode indicator 118 may be constructed of PLA.

[0026] In some implementations, the non-magnetic table 120 may be constructed of stainless steel. In some implementations, the non-magnetic table 120 and / or the base 170 may be manufactured by additive manufacturing (e.g., 3D printing). In this example, the non-magnetic table 120 and the base 170 may be constructed of composite carbon fiber polylactic acid PLA. Additionally, the base 170 may take on a variety of shapes suitable for applying the force of the exciter device to the device / structure under test (e.g., a wedge for an inclined surface and / or a rounded adapter for a curved surface). In some implementations, the non-magnetic table 120 may include one or more notches configured to receive a c-shaped washer clip as a mechanism for securing the permanent ring magnet 130 to the non-magnetic table 120.

[0027] 2A and 2B show an example of an exciter device 100 with an impact hammer attachment component 200 configured to controllably apply an impact force to a device / structure under test in addition to (or instead of) a vibration force. As described above, the upper support plate 114 of the movable housing 110 in the example of FIG. 1A is selectively coupleable to the cylindrical body 116 of the movable housing 110. Thus, in some implementations, the upper support plate 114 can be removed from the cylindrical body 116 and replaced with the impact hammer attachment component 200. As shown in FIG. 2A, in this example, the impact hammer attachment component 200 includes a helical structure similar to the helical structure of the upper support plate 114 and is thus selectively engageable with the cylindrical body 116 by a threading action. As shown in FIG. 2A, the impact hammer attachment component 200 includes a housing 202, a fixing screw 210, and a hammer tip 212 coupled to the fixing screw 210. The housing 202 of the impact hammer attachment component 200 includes an opening disposed to receive the second end of the non-magnetic table 120. In the example of FIG. 2A, a fixing screw 210 is disposed in the opening of the housing 202 and coupled to the housing 202 of the impact hammer attachment component 200. The fixing screw 210 is disposed to align with the non-magnetic table 120. The fixing screw 210 includes a hammer tip 212. The hammer tip 212 is secured to an end of the fixing screw 210 and is disposed to contact the second end (e.g., the top end) of the non-magnetic table 120 when the first end of the non-magnetic table 120 is coupled to the base 170 as described above. For example, instead of providing a vibration force by applying an alternating current to the coil 165, the moveable housing 110 is configured to provide an impact force to the device / structure under test that moves the moveable housing 110 upward and away from the surface of the device / structure under test by applying a first control signal / current to the coil while the impact hammer attachment component 200 is coupled to the moveable housing 110. Following this, an opposite current is applied to the coil 165 to move the moveable housing 110 more quickly in the opposite / downward direction relative to the surface of the device / structure under test.The rapid downward movement causes the hammer tip 212 to contact the edge of the non-magnetic table 120, thereby imparting an impact force through the non-magnetic table 120 to the device / structure under test.

[0028] The example of FIG. 2A is just one example of an implementation configured to apply an impact force. Other configurations for generating an impact force between the non-magnetic table 120 and either the movable housing 110 or the impact hammer attachment component 200 are also possible. For example, in some implementations, the hammer tip 210 may be attached to a distal end of the non-magnetic table 120 and configured to impact a surface of the impact hammer attachment component 200 and / or other upper support plate. In other implementations, a structure / component of the non-magnetic table 120 may be configured to impact a structure / component of the movable housing. For example, the device may be configured such that the impact force is generated by applying a magnetic force such that the permanent ring magnet 130 is aligned along a vertical axis with a surface, protrusion, or upper plate of the movable housing 110 and causes a surface of the permanent ring magnet 130 to impact an opposing surface / structure of the movable housing 110.

[0029] Furthermore, in some implementations, the device is configured so that the elastic deformation of the impact hammer tip 212 does not corrupt the exciter measurements when used for frequency response function (FRF) testing. In some implementations, the load cell is mounted between the bottom end of the non-magnetic table 120 and the base 170 (i.e., downstream of the impact tip). Thus, the load cell can accurately measure the force applied to the structure / device under test and adjust the applied magnetic force to the target force. In this way, measurement uncertainties due to the elastic deformation of the hammer tip 212 are reduced or avoided altogether.

[0030] In the example of Fig. 2A, the radial guide bushing 140 is disposed in an opening of the housing 202 of the impact hammer attachment component 200. The radial guide bushing 140 is coupled to the housing 202 of the impact hammer attachment component 200. The radial guide bushing 140 surrounds the non-magnetic table 120 and guides the movement of the movable housing 110 and the housing 202 relative to the non-magnetic table 120. Furthermore, the axial suspension ring magnet 150 is disposed in an opening of the housing 202 of the impact hammer attachment component 200. The axial suspension ring magnet 150 is coupled to the housing 202 of the impact hammer attachment component 200.

[0031] The fixation screw 210 is formed as a cylindrical body having a helical structure on its outer surface, and the housing 202 includes an opening having a counter-formed helical structure for receiving and engaging the fixation screw 210 by a threading action. In this manner, the fixation screw 210 can be selectively coupled and decoupled from the housing 202. In some implementations, this selective coupling allows the fixation screw 210 and the hammer tip 212 to be removed and replaced if the hammer tip 212 is damaged. Alternatively, in some implementations, multiple fixation screws 210 may each be provided with a different type of hammer tip 212 (materials of different hardness), thus allowing the hammer tips 212 to be selectively interchangeable to provide a hammer tip 212 suited to a particular testing protocol.

[0032] In some implementations (e.g., as described in more detail below), the impact hammer attachment component 200 can be manufactured by additive manufacturing (e.g., 3D printing). In some such implementations, the impact hammer attachment component 200 can be constructed of composite carbon fiber PLA. Similarly, in some implementations, the fixing screw 210 can be manufactured by additive manufacturing (e.g., 3D printing) and can be constructed of composite carbon fiber PLA. Additionally, the hammer tip 212 can be manufactured and constructed of a material that takes into account the material's ability to resist permanent indentation (i.e., the hardness of the material). In some implementations, the hammer tip 212 can be manufactured by additive manufacturing and can be constructed of PLA, composite iron PLA, and / or composite carbon fiber PLA. In other implementations, the hammer tip 212 can be constructed of stainless steel.

[0033] 3 shows a control system for the exciter apparatus 100. The exciter apparatus 100 is operated by a controller 301 to apply forces to the device / structure under test that allows the exciter apparatus 100 to provide various types and scalable forces based on an input signal. Furthermore, it provides consistent, repeatable and coherent measurements without experimental uncertainties due to alternating apparatus.

[0034] 3, the controller 301 includes an electronic processor 303 and a non-transitory computer-readable memory 305. The memory 305 stores data and instructions that, when executed by the electronic processor 303, provide various functions of the controller 301, including, for example, some or all of the functions described herein. The controller 301 is communicatively coupled to the exciter device 100.

[0035] In addition to storing computer-executable instructions, in some implementations, the memory 305 is also configured to store additional information regarding the exciter apparatus 100, the upper support plate 114, and / or the impact hammer attachment components 200 of the exciter apparatus 100. For example, the memory 305 may be configured to store component information (e.g., location, LED functions, etc.) and performance information (e.g., operating frequency, component constraints, goals / limits, etc.). The configuration shown in FIG. 3 illustrates only one example of the components and connections of the exciter apparatus 100. However, these components and connections may be configured in other ways and may include other components in place of or in addition to the components illustrated in the example of FIG. 3.

[0036] In some implementations, the controller 301 is communicatively coupled to the coil 165 of the exciter apparatus 100 and configured to provide control signals for operating the exciter apparatus 100. For example, in some implementations, the controller 301 may be configured to send control signals to the coil 165 in the form of a current that causes the coil 165 to generate a corresponding magnetic field that interacts with the magnetic field of the permanent ring magnet 130 of the exciter apparatus 100, which generates movement within the moveable housing 110 of the exciter apparatus 100 relative to the non-magnetic table 120. In this example, the controller 301 is configured to modify (e.g., alter the frequency, modify the amplitude, etc.) the control signal sent to the coil 165 to generate a force to be applied to a device / structure under test coupled to the exciter apparatus 100.

[0037] 4 and 5 show examples of control signals that may be applied by the controller 301 to the coil 165 to cause the exciter apparatus 100 to generate a vibration force and an impact force, respectively. As described above, the exciter apparatus 100 is configured to induce a vibration force in the device / structure under test by generating a reciprocating motion of the movable housing 110 relative to the non-magnetic table 120. In some implementations, this is accomplished by the controller 301 applying an AC current to the coil 165, for example, as shown in FIG. 4. The frequency of the induced vibration can be adjusted and regulated by adjusting the frequency of the AC current applied to the coil 165. Also, as described above, in some implementations, the coil 165 includes two coils configured in an opposing manner. Thus, application of the same AC control signal to the coil 165 causes movement in a first direction by generating a magnetic field in the first coil that attracts the permanent magnet 130 coupled to the non-magnetic table, while generating a magnetic field in the second coil that repels the permanent magnet 130.

[0038] To induce an impact force on the device / structure under test, the applied magnetic field must be configured to raise the movable housing 110 relative to the surface of the device / structure under test and then lower the movable housing 110 toward the surface of the device / structure under test at a relatively high speed. This may be accomplished by applying a control signal to the coil 165 as shown in FIG. 5. The magnetic field induced by the slowly rising current causes the movable housing 110 to move upward, while the magnetic field induced by the relatively high negative slope portion of the control signal causes a relatively high speed movement in the opposite direction. This relatively high speed downward movement of the movable housing 110 causes the hammer tip 212 to impact the top edge of the non-magnetic table 120, imparting an impact force through the non-magnetic table 120 to the device / structure under test. In some implementations, the exciter device 100 may be configured to apply only impact forces when equipped with the impact hammer attachment component 200 and only vibration forces when equipped with the upper support plate 114. In other implementations, the exciter device 100 may be configured to selectively apply both impact and vibration forces when equipped with the impact hammer attachment component 200 .

[0039] FIG. 6 illustrates an example of a method executed by the controller 301 to operate the exciter device 100. In some implementations, the controller 301 determines whether the exciter device includes an attachment component (step 402). In the example of FIG. 6, the controller 301 determines whether the exciter device 100 includes an impact hammer attachment component 200. For example, the electronic processor 303 receives an input from a user interface of the controller 301 indicating whether the exciter device 100 includes an impact hammer attachment component 200 or an upper support plate 114. In other implementations, the exciter device 100 is configured with circuitry that automatically determines whether the impact hammer attachment component 200, the upper support plate 114, or other attachments are coupled to the movable housing 110.

[0040] If the controller 301 determines that the exciter apparatus 100 does not include the impact hammer attachment component 200 (step 402, “no” branch), the controller 301 generates a control signal (e.g., the control signal of FIG. 4 ) for the exciter apparatus 100 to apply a vibration force to the device / structure under test. However, if the controller 301 determines that the exciter apparatus 100 includes the impact hammer attachment component 200 (step 402, “yes” branch), the controller 301 generates a control signal (e.g., the control signal of FIG. 5 ) for the exciter apparatus 100 to apply an impact force to the device / structure under test. As described above, in some implementations, the exciter apparatus 100 may be configured to selectively provide an impact force and a vibration force when equipped with the impact hammer attachment component 200. Thus, in some implementations, the controller 301 is configured to transmit a control signal for either an impact force or a vibration force based on a user selection or according to a predetermined test protocol in response to determining that the impact hammer attachment component 200 is coupled to the movable housing 110.

[0041] The controller 301 generates a control signal for the applicable force to be applied to the device / structure under test (step 404) and sends the control signal to the exciter apparatus 100. In some implementations, the controller 301 may be configured to apply the control signal to the exciter apparatus 100 as a current signal applied to the coil 165 to controllably adjust the magnetic field applied by the coil 165. In some implementations, the controller 301 utilizes the electronic processor 303 and instructions / settings stored in the memory 305 to generate the control signal for the exciter apparatus 100. For example, the controller 301 generates an electrical signal having characteristics of amplitude, frequency, and waveform. In some implementations, the controller 301 is configured to adjust the signal characteristics according to a test protocol defined by a user. In some implementations, the controller 301 may include one or more signal generators, such as, for example, a function generator, an arbitrary waveform generator, a frequency generator, etc.

[0042] The control signal generated by the controller 301 is then transmitted to the exciter device 100 (step 406). In some implementations, as described above, the control signal is transmitted to the exciter device 100 as an electric current applied to the coil 165 of the non-magnetic bobbin 160 of the exciter device 100. The electric signal passes through opposing windings of the coil 165 of the non-magnetic bobbin 160, generating a magnetic field corresponding to the electric signal. The coil 165 and the non-magnetic bobbin 160 are electromagnets (e.g., solenoids), which generate an induced magnetic field centered at the center of the non-magnetic bobbin 160 and / or the coil 165 corresponding to the electric signal (e.g., electric current) passing through the wire of the coil 165. Additionally, the controller 301 may modify characteristics of the electric signal to affect the induced magnetic field.

[0043] In the example of FIG. 6, the base 170 and non-magnetic table 120 of the exciter apparatus 100 apply the force of the movable housing 110 and / or the impact hammer attachment component 200 to the device / structure under test. For example, the non-magnetic table 120 of the exciter apparatus 100 directs the movement of the movable housing 110 to the base 170 coupled to the device / structure under test. The movement of the movable housing 110 corresponds to the interaction of the induced magnetic field of the coil 165 of the non-magnetic bobbin 160 with the magnetic field of the permanent ring magnet 130, generating repulsive and attractive forces that induce continuous vibrations in the non-magnetic table 120. In one scenario, the controller 301 sends a control signal (e.g., current) having a waveform of a set frequency and variable polarity to the exciter apparatus 100 that induces an alternating magnetic field when passing through the coil 165 of the movable housing 110 that interacts with the permanent ring magnet 130 of the non-magnetic table 120. In this scenario, the induced magnetic field of coil 165 causes moveable housing 110 to move linearly (e.g., up and down) relative to the non-magnetic table in response to a control signal. Thus, the linear motion of moveable housing 110 of exciter apparatus 100 induces continuous vibrations in the device under test that is coupled to non-magnetic table 120 via base 170.

[0044] In some implementations, the base 170 and non-magnetic table 120 of the exciter device 100 apply the force of the movable housing 110 and / or the impact hammer attachment component 200 to the device / structure under test. Movement of the movable housing 110 corresponding to the interaction of the induced magnetic field of the coil 165 of the non-magnetic bobbin 160 with the magnetic field of the permanent ring magnet 130 brings the hammer tip 212 of the impact hammer attachment component 200 into contact with a second end of the non-magnetic table 120 coupled to the device / structure under test. Thus, a force (e.g., an impact force) corresponding to the contact between the second end of the non-magnetic table 120 and the hammer tip 212 of the impact hammer attachment component 200 is directed to the device / structure under test. In some implementations, a load cell (force transducer) mounted between the first end of the non-magnetic table 120 and the base 170 is used to measure the force directed to the device / structure under test.

[0045] In some implementations of the example of FIG. 4, the above methodologies may be used alone or in combination to utilize the non-magnetic table 120 to apply the force of the moveable housing 110 and impact hammer attachment components 200 of the exciter apparatus 100 to the device / structure under test. Various embodiments of the present invention provide a controllable excitation mechanism that provides the functionality of a modal hammer and an integrated shaker within a single exciter apparatus. As a result, the exciter apparatus can eliminate the need for a multi-exciter configuration and provide accurate and repeatable results in impact testing.

[0046] In some implementations, the controller 301 also provides a control input to the mode indicator 118 of the exciter device 100 to indicate an operational mode of the exciter device 100 (step 408). In some implementations, the controller 301 is configured to provide a binary (i.e., on / off) signal to the mode indicator 118 to indicate only whether the exciter device 100 is operating (e.g., turning on an LED light of the mode indicator 118 when (a) a control signal current is applied to the coil 165 and / or (b) the exciter device 100 is communicatively coupled to the controller 301). In other implementations, the controller 301 may be configured to operate the mode indicator 118 to convey other information including, for example, (1) a current operational mode (e.g., vibration or shock), (2) an active / inactive status, (3) an error indication, and / or (4) a location / grouping of multiple exciter devices. In some implementations, the controller 301 and the mode indicator 118 are configured to utilize different functions of the LED of the mode indicator 118, such as illumination, illumination intensity, flashing, different colors, etc., to indicate the status of the exciter device 100. For example, the mode indicator 118 may illuminate with a first predetermined intensity and / or a first color when the exciter device is providing an impulse force and illuminate with a second, different predetermined intensity and / or a second color when the exciter device 100 is providing a vibration force.

[0047] Thus, the controller 301 of FIG. 3 is operable to apply a control signal (e.g., current) to the coil 165 of the exciter device 100 to generate a magnetic field. This controllable magnetic field interacts with a permanent ring magnet 130 coupled to the non-magnetic table 120 to cause movement of the moveable housing 110 relative to the non-magnetic table 120. In some implementations, axial and radial suspensions are incorporated into the exciter device 100 to damp the linear motion of the moveable housing 110 and / or limit the motion of the moveable housing 110 to a prescribed range. FIG. 7 illustrates the magnetic axial and radial suspensions of the exciter device 100. The axial and radial suspension components of FIG. 7 are also shown in the examples of FIG. 1A and FIG. 2A above, but are shown in more detail in FIG. 7 for clarity.

[0048] As shown in Fig. 7, the axial and radial suspension of the exciter device 100 includes a permanent ring magnet 130, a radial guide bushing 140, and an axial suspension ring magnet 150. The permanent ring magnet 130 is fixedly coupled to the non-magnetic table 120. Also, the permanent ring magnet 130 includes at least one permanent magnet. For example, the permanent ring magnet 130 of the magnetic axial suspension may be an annular ring magnet and may be axially magnetized.

[0049] The magnetic axial suspension of the exciter device 100 includes at least one instance of an axial suspension ring magnet 150. The axial suspension ring magnet 150 is disposed to surround the non-magnetic table 120 (e.g., a piston). The axial and radial suspension of the exciter device 100 also includes at least one instance of a radial guide bushing 140. The radial guide bushing 140 is also disposed to surround the non-magnetic table 120 (e.g., a piston). The radial guide bushing 140 guides the movement of the non-magnetic table 120 (i.e., aligns the movement of the non-magnetic table 120 with the opening of the movable housing 110). As mentioned above, in some implementations, the opening of the radial guide bushing 140 is designed to provide zero clearance between the radial guide bushing 140 and the non-magnetic table 120 (i.e., the radial guide bushing 140 contacts the non-magnetic table 120 around the entire circumference of the non-magnetic table 120). Additionally, in some implementations, the structure of the movable housing 110 provides an axial "preload" compression of the radial guide bushing 140, thereby causing the radial guide bushing 140 to expand radially.

[0050] In this example, the magnetic axial suspension of the exciter device 100 includes a radial guide bushing 140 and an axial suspension ring magnet 150 located at each end of the movable housing 110. Thus, in FIG. 7, the radial guide bushing 140 and the axial suspension ring magnet 150 located at the bottom of the movable housing 110 (i.e., near the opening of the lower support plate 112) are labeled as radial guide bushing 140-1 and axial suspension ring magnet 150-1, respectively. Similarly, the radial guide bushing 140 and the axial suspension ring magnet 150 located at the top of the movable housing 110 (i.e., either near the opening of the upper support plate 114 or near the opening of the housing 202 of the impact hammer attachment component 200) are labeled as radial guide bushing 140-2 and axial suspension ring magnet 150-2, respectively. Each ring magnet 130, 150 includes two magnetic poles. In the example of FIG. 7, the north magnetic pole is indicated by the letter A and the south magnetic pole is indicated by the letter B. For example, the north pole of permanent ring magnet 130 is labeled 130A in FIG. 7, and the south pole of permanent ring magnet 130 is labeled 130B in FIG.

[0051] 7 is provided by the relative arrangement of the magnetic poles of the lower axial suspension ring magnet 150-1, the upper axial suspension ring magnet 150-2, and the permanent ring magnet 130. In particular, the south magnetic pole 150-1B of the lower axial suspension ring magnet 150-1 is configured to face the south magnetic pole 130B of the permanent ring magnet 130, such that the respective magnetic fields of the permanent ring magnet 130 and the axial suspension ring magnet 150-1 interact to generate a repulsive force. This repulsive force inhibits movement of the movable housing 110 as the lower axial suspension ring magnet 150-1 approaches the permanent ring magnet 130, and also limits the distance that the first end of the non-magnetic table 120 can extend relative to the lower axial suspension ring magnet 150-1. Similarly, the north magnetic pole 150-2A of the axial suspension ring magnet 150-2 is configured to face the north magnetic pole 130A of the permanent ring magnet 130, such that the respective magnetic fields of the permanent ring magnet 130 and the upper axial suspension ring magnet 150-2 interact to generate a repulsive force. This repulsive force inhibits movement of the movable housing 110 as the upper axial suspension ring magnet 150-2 approaches the permanent ring magnet 130, and also limits the distance that the second end of the non-magnetic table 120 can extend relative to the upper axial suspension ring magnet 150-2. The configuration of the axial suspension ring magnets 150-2, 150-1 provides a stable equilibrium position for the permanent ring magnet 130 at the center of the bobbin.

[0052] Further, in some implementations, the axial and radial suspension systems are configured such that operation of the magnetic axial suspension provides additional axial compression (and thus corresponding radial expansion) of the radial guide bushings 140-1, 140-2. In particular, as the permanent ring magnet 130 approaches the axial suspension ring magnet 150-2, the opposing magnetic forces between the permanent ring magnet 130 and the axial suspension ring magnet 150-2 cause the axial suspension ring magnet 150-2 to apply a greater axial compressive force against the radial guide bushing 140-2, thereby increasing the stiffness of the radial guide bushing 140-2 relative to the non-magnetic table 120. Conversely, as the permanent ring magnet 130 approaches the axial suspension ring magnet 150-1, the opposing magnetic forces between the permanent ring magnet 130 and the axial suspension ring magnet 150-1 cause the axial suspension ring magnet 150-1 to apply a greater axial compressive force against the radial guide bushing 140-1, thereby increasing the stiffness of the radial guide bushing 140-1 relative to the non-magnetic table 120.

[0053] 7 and described above provides several benefits and advantages in some implementations: first, the suspension allows the non-magnetic table 120 to be rotated 360° for threaded coupling with the device under test. Also, after assembly, the movable housing 110 can be freely rotated around the non-magnetic table 120 even while the non-magnetic table 120 is fixed to the device under test, which allows more user flexibility in positioning and routing cables coupled to the exciter apparatus 100, for example.

[0054] 8A-8J show an example of the exciter apparatus 100 of FIGS. 1A-2B. In some implementations, these components of the exciter apparatus 100 (e.g., the shaker apparatus) can be manufactured using additive manufacturing (e.g., three-dimensional (3D) printing). For example, the components of the exciter apparatus 100 are 3D printed using fused deposition modeling with a desktop 3D printer, where the components of the exciter apparatus 100 are created layer by layer by applying a molten filament through the nozzle of the desktop printer to form the components. In this example, the molten filament can be plastics with various material properties (e.g., iron-filled metal composite polylactic acid (PLA), black carbon fiber composite heat-treatable PLA (HTPLA), stainless steel composite metal filament, etc.). In another example, the components of the shaker apparatus are 3D printed using fused deposition modeling with an industrial 3D printer, where the components of the shaker apparatus are created layer by layer by applying a molten filament through the nozzle of the industrial printer to form the components. In this example, the molten filament can be metal (e.g., stainless steel) instead of plastic. In other examples, shaker device components are 3D printed using selective laser sintering, also known as SLS printing, in which a laser selectively sinters particles of polymer or metal powder, fusing them together and building the components layer by layer.

[0055] In the example of FIG. 8A, a perspective view of the cylindrical body 116 is shown. The cylindrical body 116 may be made using additive manufacturing. For example, the cylindrical body 116 may be made using a filament having magnetic properties that interact with the magnetic flux generated by the coil 165 for better performance (i.e., generating movement) of the exciter device 100. In another example, the cylindrical body 116 may be made of metal (e.g., using an industrial printer and metal wire) to increase the weight of the cylindrical body 116. Thus, during operation, higher forces are applied to the device / structure under test as the cylindrical body 116 moves up and down with increased dynamic mass due to the metal. The cylindrical body 116 may include an application-specific identifier (e.g., embossed text, delicate symbols, etc.) to identify a particular shaker device within a large array of shakers. Incorporating an identifier using traditional methods is difficult to achieve when machining an object using subtractive techniques. 3D printing offers a cost-effective solution.

[0056] In yet another example, the cylindrical body 116 may be made of two or more different materials in one solid shaker body by using plastics with ferromagnetic iron particles where special magnetic properties are required, and carbon fiber reinforced plastics for increased structural strength that cannot be achieved by conventional machining. In one scenario, the central segment of the cylindrical body 116 in close proximity to the bobbin 160 and the generated magnetic field may be constructed of a magnetic material, while the remaining segments of the cylindrical body 116 may be constructed of a non-magnetic material or a carbon fiber reinforced material. Also, conductive filaments may be used in constructing the cylindrical body 116 to achieve low-cost wire terminals printed directly onto the non-conductive housing of the shaker device. In yet another example, the cylindrical body 116 may include angled through holes, notches, or other types of channels that are shapes / geometry that are difficult, impossible, and / or economically unfeasible to fabricate using conventional methods.

[0057] In the example of FIG. 8B, a perspective view of a non-magnetic bobbin 160 including a coil 165 is shown. In this example, the bobbin 160 is made by additive manufacturing using a heat-resistant non-magnetic metal (e.g., brass). The coil 165 is wound onto the bobbin 160 using an automatic winding machine. The bobbin 160 may include one or more axial notches on the circumference of the non-magnetic bobbin 160 to improve wire routing. Forming this bobbin 160 with axial notches and winding the coil 165 around the bobbin 160 using conventional milling would involve multiple rotation steps plus an additional milling step. However, using 3D printing to make the bobbin 160 reduces manufacturing time, complexity, and cost.

[0058] The bobbin assembly (i.e., bobbin 160 with coil 165 wound on it) is designed and dimensioned to be pressed into cylindrical body 116, as shown in FIG. 8C. The mode indicator 118 is also designed and dimensioned to nest around a portion of cylindrical body 116, as shown in FIG. 8C. FIG. 8D shows a perspective view of mode indicator 118 as a separate component. In this example, bobbin 160, cylindrical body 116, and mode indicator 118 are formed separately as separate components using 3D printing and then assembled as shown in FIG. 8C. However, in some implementations, cylindrical body 116 is 3D printed directly around wound bobbin 160 and / or mode indicator 118 is 3D printed directly on cylindrical body 116. 3D printing components directly on each other in this manner avoids additional assembly steps and also eliminates tolerance issues (e.g., undesired gaps / movements between components due to slight variations in size).

[0059] FIG. 8E shows an example of a non-magnetic table 120 with a pair of ring magnets 130 coupled to it. In some implementations, the table 120 is formed (e.g., by machining) from an aluminum material. In other implementations, the table 120 is 3D printed using carbon fiber reinforced plastic. By 3D printing the table 120 using a material that is both stiff / rigid and lightweight, the table 120 can transmit forces to the device / structure under test while also reducing the static mass loading on the device / structure under test. Mass loading changes the structural dynamic properties of the device / structure under test, and therefore the excess weight of the table 120 will cause measurements with the exciter device 100 attached to the device / structure under test to differ from the actual dynamic properties of the device / structure under test.

[0060] As shown in FIG. 8E, multiple ring magnets 130 are arranged in series on the table 120 with opposing poles touching so that the multiple ring magnets 130 together act as a single larger magnet. In this example, ferromagnetic disks 124 are arranged on either side of the ring magnets 130 to secure the permanent ring magnets 130 to the table 120 (i.e., prevent the magnets from sliding and rotating) and, in some implementations, act as a retaining device to linearize the magnetic field at the end regions of the permanent ring magnets 130 and coils 165. In some implementations, the linearization of the magnetic field can help linearize the output force when operating the exciter device 100 at large displacements. A clip 122 (e.g., a "c" shaped washer) engages with a groove on the shaft of the table 120 on the outside of the disks 124. In other implementations, the functionality of the ferromagnetic disks 124 and the c-shaped clips shown in the example of FIG. 8E may be realized as one 3D printed part.

[0061] FIG. 8F provides a perspective view of the lower support plate 112 according to one implementation. The lower support plate 112 is formed with an integral clip structure 112A formed concentrically with an opening in the lower support plate 112 and sized to receive both the radial guide bushing 140 and the axial suspension ring magnet 150. As shown in the example of FIG. 8F, the radial guide bushing 140 is disposed within the lower support plate 112 around the opening, and the axial suspension ring magnet 150 is disposed above the radial guide bushing 140. The clip structure 112A clips the axial suspension ring magnet 150 in place using a pretension to couple the radial guide bushing 140 and the axial suspension ring magnet 150 to the lower support plate 112. Due to the stacked arrangement of the axial suspension ring magnet 150 and the radial guide bushing 140 when coupled to the lower support plate 112, the radial guide bushing 140 is not visible in FIG. 8F. However, the radial guide bushing 140 is shown in FIG. 8G prior to assembly.

[0062] 8F example shows the assembly of the lower support plate 112, in some implementations, a similar clip structure 112A is also incorporated into the upper support plate 114 and / or housing 202 of the impact hammer attachment component 200 to engage and retain corresponding radial guide bushings and / or axial suspension ring magnets. The support plates 112, 114 are 3D printed using carbon fiber reinforced plastic to avoid deformation in the areas of the radial guide bushings 140 and axial suspension ring magnets 150 and to increase the stiffness of these high load areas of the shaker apparatus.

[0063] FIG. 8H illustrates an example of the housing 202 of the impact hammer attachment component 200. The housing 202 may be 3D printed using carbon fiber PLA and / or stainless steel materials. In this example, the composition of the housing 202 may vary based on the target weight of the specification test application (i.e., a heavier housing 202 can provide a greater impact force). FIG. 8I illustrates an example of the fixing screw 210 and the hammer tip 212 of the impact hammer attachment component 200. In some implementations, the fixing screw 210 and the hammer tip 212 are 3D printed using carbon fiber PLA and / or stainless steel materials. In various implementations, the fixing screw 210 and the hammer tip 212 may be formed of the same material or different types of materials. In some implementations, the hammer tip 212 is coupled to the fixing screw 210 as a separate assembly step, and in other implementations, the hammer tip 212 is 3D printed directly on the fixing screw 210. In this example, the set screw 210 is formed with a helical outer surface configured to engage a corresponding helical formation within the top opening of the housing 202 of the impact hammer attachment component 200, such that the set screw 210 and the hammer tip 212 are selectively coupleable to the housing 202. However, in other implementations, the set screw 210 and the hammer tip 212 may be integrally formed as part of the housing 202 of the impact hammer attachment component 200.

[0064] 8J, a perspective view of the key 410 is shown. In some implementations, the key 410 is 3D printed using carbon fiber reinforced plastic material and formed to correspond to the unique shape of the impact hammer attachment component 200, the lower support plate 112, and / or the upper support plate 114. Thus, the key-lock design of the support plates prevents disassembly of the components without specific tools (i.e., only authorized users can modify the shaker device).

[0065] FIG. 9 shows an example of a method for assembling the exciter device 100. First, the cylindrical body 116, the bobbin 160, the mode indicator 118, the upper support plate 114, and the lower support plate 112 are formed (described above) using 3D printing (step 901). The bobbin 160 is wound with a coil 165 (step 903), and the wound bobbin is pressed into the cylindrical body 116 (step 905). The mode indicator 118 is then placed in place on the cylindrical body 116 (step 907), as shown in FIG. 8C. The radial guide bushing 140 and the axial suspension magnet 150 are coupled to the upper support plate 114 and the lower support plate 112 (step 909), as shown in FIG. 8F. Next, the table assembly of FIG. 8E is assembled (step 911) and placed inside the bobbin assembly (step 913). The lower support plate 112 and the upper support plate 114 are then locked into place using the key 410 (step 915).

[0066] In the example of FIG. 9, the various components of the exciter device 100 are manufactured separately and then assembled. However, as described above, in some implementations, the various components are formed in place by 3D printing the components directly onto the other components. FIG. 10 shows another example of a method for assembling the exciter device 100 by 3D printing the components directly onto one another. First, as shown in FIG. 8B, the bobbin 160 is 3D printed (step 1001) and the coil 165 is wound onto the bobbin 160 (step 1003). The cylindrical body 116 is then 3D printed directly onto the bobbin assembly (step 1005), and the mode indicator 118 is 3D printed directly onto the cylindrical body 116 (step 1007). Next, as shown in FIG. 8F, the upper support plate 114 and the lower support plate 112 are formed using 3D printing (step 1009), and the radial guide bushing 140 and the axial suspension magnet 150 are bonded to the upper support plate 114 and the lower support plate 112 (step 1011). Next, the table assembly of FIG. 8E is assembled (step 1013) and placed inside the bobbin assembly (step 1015). The lower support plate 112 and the upper support plate 114 are then fixed in place using a key 410 (step 1017).

[0067] In some implementations of the above-mentioned systems and methods, different materials can be combined in one printed part by switching between different printed materials (e.g., using plastic with ferromagnetic iron particles where special magnetic properties are needed and using carbon fiber reinforced plastic to increase structural strength). The different materials are combined globally by the associated printing process. In this way, it is possible to achieve high-strength parts with specific "local" properties. Similar variety of materials in one "solid" part cannot be achieved by conventional machining techniques. For example, in some implementations, the central portion of the cylindrical body 116 (closest to the magnetic field generated through the bobbin 160 and coil 165) is formed to include magnetic material, while the remaining body (and support plate) is formed of non-magnetic material or carbon fiber reinforced material. Also, conductive filaments can be used to realize low-cost wire terminals printed directly on the non-conductive housing (e.g., cylindrical body 116) of the exciter device 100. Similarly, in some implementations, the locking screw 210 of the impact hammer attachment component is 3D printed from a hard carbon fiber plastic, and the hammer tip 212 is 3D printed directly onto the locking screw 210 using a plastic material with a different elasticity.

[0068] In some implementations, the cylindrical body 116 may be 3D printed to include angled through holes for wire routing, notches required for wire guidance during assembly, or other types of channels. These shapes / geometry are difficult (or impossible) to machine with conventional processes and would be very expensive.

[0069] In various implementations, the size (and therefore output force) of the exciter apparatus 100 is scalable. For example, to print a larger exciter apparatus 100 to provide sufficient excitation for testing on commercial vehicles, trucks, and marine vessels (i.e., application-specific "shakers"), all parts can be printed with a scaling factor of 2x. In some implementations, most of the components of the exciter apparatus 100 (except for the ring magnet, radial guide bushings, and coils) can be 3D printed. A larger shaker with more coil windings, a larger (stronger) magnet, and a higher dynamic mass of the cylindrical body 116 can provide higher force excitation. Similarly, a smaller shaker (scaling factor <1) can be 3D printed, for example, for durability testing of electronic components with limited access. Additionally, 3D printed parts are customizable. For example, the base 170 can be 3D printed in a form factor designed to connect to curved surfaces and / or other complex geometries.

[0070] Thus, the examples described herein above provide, among other things, an exciter apparatus for inducing vibration and / or impact forces in a device / structure under test, as well as a mechanism for manufacturing the exciter apparatus using 3D printing. Further features and advantages of these systems and methods are set forth in the following claims.

[0071] As used herein, relational terms such as first and second, upper and lower, etc. may be used only to distinguish one entity or operation from another entity or operation without necessarily requiring or implying an actual such relationship or order between such entities or operations. The terms "comprises," "comprising," "has," "having," "includes," "including," "contains," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion, whereby a process, method, article, or apparatus that comprises, has, includes, or contains a list of elements may include other elements not expressly listed or inherent to such process, method, article, or apparatus, rather than including only those elements. An element followed by "comprises...a," "has...a," "includes...a," or "contains...a" does not, without further constraints, exclude the presence of additional identical elements in the process, method, article, or apparatus that comprises, has, includes, or contains that element. The terms "a" and "an" are defined as one or more, unless otherwise noted herein. The terms "substantially," "essentially," "approximately," "about," or any other version thereof, are defined as close to what would be understood by one of ordinary skill in the art. The term "coupled," as used herein, is defined as connected, but not necessarily directly, and not necessarily mechanically. A device or structure that is "configured" in a particular way is configured in at least that way, but may be configured in unrecited ways.

Claims

1. 1. An exciter device, comprising: a piston, a first end of the piston being coupleable to a surface of a device under test; a permanent ring magnet fixedly coupled to the piston; a movable housing disposed around the piston, the movable housing being linearly movable relative to the piston; an electromagnet coupled to the movable housing and configured to receive an electrical signal input to generate a magnetic field that impinges on the permanent ring magnet; the exciter apparatus is configured to apply a vibration force to the device under test when the electrical signal input causes the electromagnet to generate an alternating magnetic field, the alternating magnetic field applied to the permanent ring magnet causing a linear reciprocating motion of the movable housing relative to the piston; the exciter apparatus is an electromagnet configured to apply an impulse force to the device under test when the electrical signal input causes the electromagnet to generate a magnetic field that, when applied to the permanent ring magnet, induces linear movement of the moveable housing sufficient to induce contact between a first position fixed relative to the piston and a second position fixed relative to the moveable housing; An exciter device comprising:

2. 2. The exciter apparatus of claim 1, further comprising an attachment component selectively coupleable to the movable housing, the attachment component including an impact hammer tip positioned in alignment with a second end of the piston, and the impact force being applied by contacting the impact hammer tip with the second end of the piston.

3. The accessory components include: an accessory housing having an opening disposed to be aligned with an axis of linear motion of the piston when the accessory is coupled to the movable housing; a fastening screw selectively connectable to the accessory component housing inside the opening; a hammer tip secured to a first end of the set screw; 3. The exciter apparatus of claim 2, comprising:

4. 3. The exciter apparatus of claim 2, wherein the attachment component includes a helical structure, the moveable housing includes a corresponding helical structure, and the attachment component is selectively coupleable to the moveable housing by engaging the helical structure with the corresponding helical structure via a threaded action.

5. 3. The exciter apparatus of claim 2, further comprising an upper support plate, said upper support plate being selectively and interchangeably coupleable to said moveable housing in place of said accessory component, said upper support plate including an opening disposed to be aligned with an axis of said linear motion of said piston when said upper support plate is coupled to said moveable housing such that said second end of said piston does not contact said upper support plate during movement of said moveable housing relative to said piston.

6. a lower support plate having a lower opening aligned with the axis of the linear motion of the piston, the first end of the piston passing through the lower opening; an axial suspension magnet coupled to the movable housing adjacent the lower opening and positioned to have an opposite magnetic polarity to that of the permanent ring magnet, wherein opposing magnetic forces between the axial suspension magnet and the permanent ring magnet damp movement of the movable housing relative to the piston as the axial suspension magnet approaches the permanent ring magnet; a radial guide bushing disposed adjacent the lower opening and circumferentially surrounding the piston, the radial guide bushing being formed of a flexible and compressible material and limiting radial movement of the movable housing relative to the piston; The exciter apparatus of claim 1 further comprising:

7. 1. A force response testing system comprising: An exciter device according to claim 1; 1. An electronic controller comprising: sending a first control signal to the exciter device, the first control signal configured to cause the electromagnet of the exciter device to generate a first magnetic field that moves the impact hammer in a direction away from the second end of the piston; sending a second control signal to the exciter device after sending a first control signal to the exciter device, the second control signal configured to cause the electromagnet of the exciter device to generate a second magnetic field that drives the first location fixed relative to the piston into contact with the second location fixed relative to the movable housing. An electronic controller; A force response testing system comprising:

8. 8. The force response testing system of claim 7, wherein the electronic controller is configured to transmit the first control signal and the second control signal by controllably adjusting a current applied to a coil of the electromagnet.

9. 9. The force response testing system of claim 8, wherein the electronic controller is further configured to apply an alternating current to the coil of the electromagnet, the alternating current causing the electromagnet to generate the alternating magnetic field and apply the vibration force to the device under test.

10. 10. The force response testing system of claim 9, wherein the electronic controller is configured to adjust the amplitude and frequency of the vibration force applied to the device under test by adjusting the amplitude and frequency of the alternating current applied to the coil of the electromagnet.

11. 8. The force response testing system of claim 7, wherein the exciter device further includes a mode indicator including at least one light emitting diode, and the electronic controller is further configured to send a mode indicator control signal to the at least one light emitting diode of the mode indicator, the mode indicator control signal configured to operate the light emitting diode to provide a visual indication of an operational mode of the exciter device.

12. 1. A method for applying a force to a device under test, comprising: applying a vibration force to the device under test by sending a first electrical signal input to an exciter device, the exciter device comprising: a piston, a first end of the piston being coupled to a surface of the device under test; a permanent ring magnet fixedly coupled to the piston; an impact hammer tip coupled to the movable housing and positioned in alignment with a second end of the piston, the second end being opposite the first end; a movable housing disposed around the piston, the movable housing being linearly movable relative to the piston; Including, applying the first electrical signal input configured to cause the electromagnet to generate an alternating magnetic field applied to the permanent ring magnet that induces linear reciprocating motion of the moveable housing relative to the piston; applying, by an electronic controller, an impact force to the device under test by sending a second electrical signal input to the exciter device, the second electrical signal input configured to cause the electromagnet to generate a magnetic field applied to the permanent ring magnet that causes linear movement of the moveable housing sufficient to drive the impact hammer tip of the moveable housing into contact with the second end of the piston; A method comprising:

13. Transmitting the first electrical signal input to the exciter device comprises: generating an alternating current; applying said alternating current to a coil of said electromagnet; The method of claim 12, comprising:

14. 14. The method of claim 13, further comprising adjusting the amplitude and frequency of the vibrational force applied to the device under test by adjusting the amplitude and frequency of the alternating current applied to the coil of the electromagnet.

15. 13. The method of claim 12, wherein applying the impact force to the device under test further comprises sending a pre-impact electrical signal input to the exciter device, the pre-impact electrical signal input configured to cause the electromagnet to generate a pre-impact magnetic field applied to the permanent ring magnet that causes a pre-impact linear motion of the movable housing that moves the impact hammer tip away from the second end of the piston prior to applying the second electrical signal input that drives the impact hammer tip into contact with the second end of the piston.

16. 13. The method of claim 12, wherein sending the second electrical signal input to the exciter device includes applying a current to a coil of the electromagnet, the method further including adjusting a magnitude of the current applied to the coil of the electromagnet to thereby adjust a magnitude of the impact force.

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