Abstract: A device for testing a vehicle includes at least one sound recording device, which is designed for recording the sound emitted by a vehicle to be tested, and an evaluation device, which is designed for evaluating the sound recorded by the at least one sound recording device. The device may include at least one image recording device, which is designed for recording at least one image of the vehicle to be tested, and a display device which is designed for representing the source(s) of the recorded sound in at least one image of the vehicle to be tested.

Abstract: According to the present invention, use is made of a probe provided with a central sensor, with off-centered sensors and lateral sensors, and said probe is articulated on the aircraft around two orthogonal axes.

Abstract: Systems and methods for providing a multi-direction wind tunnel, or “windball,” are disclosed. The system can have a series of fans configured to provide air flow in a plurality of directions to enable accurate testing of aircraft, unmanned aerial vehicles (UAVs), and other vehicles capable of multi-dimensional flight. The system can comprise a spherical or polyhedral test chamber with a plurality of fans. The fans can be arranged in pairs, such that a first fan comprises an intake fan and a second fan comprises an exhaust fan. The direction of the air flow can be controlled by activating one or more pairs of fans, each pair of fan creating a portion of the air flow in a particular direction. The direction of the air flow can also be controlled by rotating one or more pairs of fans with respect to the test chamber on a gimbal device, or similar.

Abstract: The present invention provides a device for removing sweat from the inner ear by creating a vacuum in connecting tubing between the inner ear and a converging-diverging nozzle. When air enters the front of the converging-diverging nozzle, its velocity accelerates as it flows through the smaller cross-sectional area in the middle section, which causes a drop in pressure in the middle section and a resulting vacuum in the connecting tubing. This vacuum draws sweat from the bottom of the inner ear toward the middle of the converging-diverging nozzle, where it drips out of either end, resulting in sweat being removed from the inner ear.

Abstract: A method for testing water droplet shedding ability of a surface of an aircraft wing includes: blowing air toward a surface of a cylindrical member in an airflow direction perpendicular to an axial direction of the cylindrical member, the cylindrical member simulating the wing and having water-related surface characteristics that differ across a predetermined boundary position in a circumferential direction; supplying a water droplet to a portion of the surface of the cylindrical member on a leading edge side with respect to a flow of the air; and capturing an image of the water droplet that moves on the surface of the cylindrical member across the boundary position due to the flow of the air.

Abstract: Mobile tunnels may be provided on trailers or in association with one or more other vehicles. A mobile tunnel may be towed or otherwise accelerated to a sufficient velocity, thereby causing a fluid such as air or seawater to travel above, below and around the tunnel. The fluid may be diverted into the tunnel and caused to pass over a test object such as an unmanned aerial vehicle or unmanned undersea vehicle within the tunnel, thereby enabling aerodynamic testing or hydrodynamic testing of the test object to be performed. Additionally, one or more materials may be injected into the fluid, thereby enabling destructive testing of the test object to be performed.

Abstract: This disclosure provides example methods, devices, and systems for a sensor having thermal gradients. In one embodiment, a system may comprise a sensor assembly including a housing; a first header and a second header coupled to the housing; a first transducer coupled to the first header, wherein the first transducer is configured to measure a first pressure to generate a first pressure signal; a second transducer coupled to the second header, wherein the second transducer is configured to measure a second pressure to generate a second pressure signal; and wherein the first transducer and the second transducer are positioned in the housing such that a first temperature of the first transducer is about equivalent to a second temperature of the second transducer during operation of the sensor assembly.

Abstract: The invention relates to a method for simulating the unsteady aerodynamic loads being exerted on the external structure of an aircraft, notably in the context of a simulation of the buffeting of a wing surface in an airflow. The method includes a step of measurement of pressure (410) at different points of a grid, a step of calculation of the spectral density at these points (420) followed by extrapolation/interpolation operations to calculate the missing measurements (430), a step of estimation of the pressure coherence (440) for each pair of points of the grid, a step of estimation of the interspectral pressure density (450) for these same pairs of points, from the coherence thus estimated, and a step of calculation of the aerodynamic loads (460) by summing the real part of the interspectral density for the area of the wing surface having a separation of the boundary layer.

Abstract: A wind turbine blade vortex generator unit and a method for installing it, where a wind turbine blade has at least one series of vortex generator units formed of fins extending substantially perpendicular to the surface of the airfoil and substantially in a direction from the leading edge towards the trailing edge of the wind turbine blade. The vortex generator units each comprises a fin connected to an outer side of the fin base, and where the fin is delta shaped tapering from a trailing edge towards a leading edge and where each of the vortex generator units has a layer of adhesive on an inner side of the base that extends to an outermost periphery of the base. The vortex generator unit has exactly one fin, and the base has an airfoil shaped periphery with a rounded leading edge and a trailing edge.

Abstract: A rain and fog testing apparatus, comprising a fluid channel that runs between a first fluid shutoff coupler and a second fluid shutoff coupler and has at least one dispersion head fluidly coupled to the fluid channel. A liquid pump can be fluidly coupled to the fluid channel at an output end. A liquid heater may also be fluidly coupled to the system along with a controller that provides electrical control of the first fluid shutoff coupler, the second fluid shutoff coupler, the dispersion head, the liquid pump, and the heater. Further, the second fluid shutoff coupler is capable of fluidly coupling a first fluid channel to a plurality of fluid channels and the controller can adjust the orientation of the first fluid shutoff coupler, the second fluid shutoff coupler, the dispersion head, the liquid pump, and the liquid heater to create a simulation of a plurality of rain or fog events.

Abstract: The invention relates to an insert for a turbine engine test vane including the insert and a vane body. The insert includes at least two external surfaces. The insert is configured to fit into the vane body, such that the external surfaces are vane aerodynamic surfaces each forming part of a vane aerodynamic profile.

Abstract: An apparatus for assisting with measurement of a fluid pressure includes a cover layer having a leading cover edge and upper and lower cover surfaces. A cover aperture fluidly connects the upper and lower cover surfaces. A spacer layer has oppositely facing upper and lower spacer surfaces. A cavity has an upper cavity surface, defined by the lower cover surface, which includes the leading cover edge and the cover aperture. A measuring tube is located adjacent to the upper cover surface. The measuring tube includes a tube lumen. When the lower spacer surface is connected to the substrate, the substrate defines a lower cavity surface and extant fluid is present within the cavity. Variable fluid flowing toward the cavity exerts pressure on the extant fluid to generate an extant fluid pressure level which is physically transmitted through the apparatus and made available for measurement as an extant fluid pressure level.

Abstract: A wind tunnel balance, with a tunnel wall adaptor configured to fasten the wind tunnel balance to a wall of a wind tunnel, an actuator housing connected to the tunnel wall adaptor, a plurality of force sensors arranged between the actuator housing and the tunnel wall adaptor and which are configured to detect forces acting on the actuator housing, a pivot coupling, by means of which an airfoil model of an aircraft can be pivotably coupled to the actuator housing, and a plurality of piezoelectric actuators arranged in the actuator housing and which are configured to controllably deflect an airfoil model mounted on the pivot coupling in three spatial directions.

Abstract: Systems and methods for analyzing the gait of an individual are disclosed. The disclosed systems and methods can be configured to acquire data from a first array and a second array of sensors that are configured to be placed in a left and/or right shoe, respectively. The acquired data can be collected or separated into at least two separate gait phases for each array, compared to a baseline condition for each gait phase and categorized into one of at least two uniformity categories for each gait phase. Examples of collected and/or calculated data include pressure values, shear stress values and torque values. The analysis can be focused on both feet of a person, or focused on one foot. A graphical output showing at least one entire gait cycle based on the uniformity categories can then be generated.

Abstract: Various examples are provided for dynamic simulation of wind velocity and pressure. In one embodiment, among others, a dynamic wind simulator includes a fan and a fast-acting damper connected to an inlet of the fan. The fast-acting damper configured to modulate airflow provided by the fan at frequencies up to 10 Hz. In another embodiment, a system includes a fan and an air outlet path of the fan connected to a testing assembly configured to support a specimen for testing. An air inlet path of the fan includes a fast-acting damper configured to modulate airflow provided by the fan to the testing assembly at frequencies up to 10 Hz. The testing assembly may include a pressure chamber and/or a test section.

Abstract: The present invention is aimed to improve the conventional plane-opened hydrodynamic testing device, one or more than one reverse pumping return units (201) are installed with a parallel or substantially parallel manner at the periphery of an active fluid pumping unit (101), so a part of the fluid discharged from the outlet port of the active fluid pumping unit (101) is enabled to be sucked and reversely pumped for being returned to an adjacent space defined at the fluid inlet port of the active fluid pumping unit (101), thereby structuring a semi-opened hydrodynamic testing device having reverse pumping return unit.

Abstract: Systems and methods for testing ignition properties of particles in a gas. Systems include a test chamber sized to hold a particle to be tested, a gas supply configured to deliver a gas to the test chamber, a heating device configured to heat the particle, and data acquisition equipment configured to collect data associated with the particle and/or the gas. Methods include generating a flow of gas around a particle that is fixed in space relative to the flow of gas in a test chamber, heating the particle and/or heating the gas, and collecting data associated with the particle and/or the gas.

Abstract: An optical sensor comprising a light source; a sensor substrate, arranged to receive a force to be detected, the sensor substrate including an interference pattern generator, optically coupled to the light source for receiving light from the light source, and generating an interference pattern, and a detector, optically coupled to the sensor substrate for receiving the interference pattern and providing a signal which can be used to determine the force applied to the sensor substrate.

Abstract: A system and method for generating fluid flow parameter data for use in aerodynamic heating analysis. Computational fluid dynamics data is generated for a number of points in an area on a surface to be analyzed. Sub-areas corresponding to areas of the surface for which an aerodynamic heating analysis is to be performed are identified. A computer system automatically determines a sub-set of the number of points corresponding to each of the number of sub-areas and determines a value for each of the number of sub-areas using the data for the sub-set of points corresponding to each of the number of sub-areas. The value is determined as an average of the data for the sub-set of points corresponding to each of the number of sub-areas. The resulting parameter values then may be used to perform an aerodynamic heating analysis.

Abstract: The present invention relates to a rotorcraft rotor (1) having a plurality of blades (3) movably mounted on a hub (2) via blade roots (4) that are respectively associated therewith. The rotor (1) is fitted with an information capture appliance having at least one measurement assembly (E1) comprising a flexible bar (11) interposed in engagement at its respective ends between the hub (2) and a blade root (4) that is allocated thereto. A strain gauge (7, 8) formed of a SAW transducer is implanted on the bar (11) and generates information relative to the bending of the bar (11) following tilting orientations of the blade root (4) in flapping (B) and/or in lag (T).

Abstract: Methods and systems for balancing helicopter rotor blades are disclosed. In some examples, density data of a rotor blade may be acquired by scanning the rotor blade. In some examples, surface contour data of a rotor blade may be acquired by scanning the rotor blade. In some examples, simulations may be performed to predict flight data associated with a modeled rotor blade. In some examples, a database may be referenced to predict a desired weight balance and/or a desired aerodynamic balance of a rotor blade.

Abstract: An open area platform for supplementing operation of a wind tunnel balance, comprises a platform body and platform adapters. The platform adapter members have first ends and second ends. The first ends are configured to contact the platform body and the second ends are designed to be operatively coupled with the wind tunnel's balance. As a result, any load on the platform body is configured to be transmitted through the platform adapter members and measured by the wind tunnel balance. Methods of using the open area platform, including for the testing of athletes and their equipment, are also disclosed.

Abstract: A model adapter includes a first section of an off-body adapter at least partially circumscribing a sting mount, and a second section of the off-body adapter coupled to the first section such that the off-body adapter is coupled to the sting mount. The off-body adapter is positioned aft of the model to provide for a substantially aerodynamically smooth transition between a model and the sting mount.

Abstract: The present invention relates to a measuring device comprising a flexible polymer plate (1) and at least one cavity (R0) formed within the polymer plate, comprising a window opening onto an upper face of the polymer plate and configured to receive at least one physical value sensor (SR) arranged in a casing (SP0). The measuring device also comprises electrical conductors (11, 13) embedded in the polymer plate and comprising a termination extending into the cavity (R0), to electrically couple the sensor to an electrical input/output point (4) of the polymer plate. Application mainly to measurements of parietal parameters.

Abstract: A wind tunnel device defines a cyclical tunnel to receive continuous airflow. Airflow is delivered through the tunnel to a testing region that includes a first portion carrying an arm including a spray tip configured to spray particulates in the testing region at an angle, and a second portion including an enlarged cutout region configured to receive the angled sprayed particulates. As airflow carries the angled spray particulates into the second portion, the enlarged cutout region enables the spray particulates to pass through and exit the second portion of the testing region. Analysis in the second region may be conducted through transparent walls free of openings to minimize exposure of the spray particulates to the exterior of the device. A scrubber is adapted to extract spray mist from the airflow as the airflow exits the testing region and is re-circulated through the cyclical tunnel.

Abstract: A method and apparatus for identifying a position of a surface on an aircraft. Image data for an image of the surface on the aircraft is received. The image data is processed to determine whether the position of the surface on the aircraft is a desired position. A surface position identification report comprising information identifying whether the position of the surface on the aircraft is the desired position is generated.

Abstract: A device for measuring a sound source distribution in three-dimensional space is provided in which tracer particles included around an object are irradiated with a two-dimensional laser sheet within an x-y plane at two times separated by a short time interval, images of the irradiated tracer particles are taken, and two in-plane velocity components of the tracer particles in the laser sheet and one out-of-plane velocity component perpendicular to the laser sheet are measured based on the images taken. Further, the velocity field of the three velocity components in three-dimensional space is measured by obtaining three velocity components within a plurality of planes spaced apart in a z-axis direction perpendicular to the laser sheet and stacking the three velocity components within the plurality of planes in the z-axis direction. The sound source distribution around the object is measured from the velocity field.

Abstract: A microparticle count apparatus that includes or is connected to a gas reservoir for increasing stability of air pressure at the microparticle counter even when air pressure or air flow rate provided by a nozzle coupled to the microparticle measurement apparatus is unstable.

Abstract: In accordance with one aspect of the present disclosure, an apparatus and a method of testing one of aerodynamic and acoustic characteristics of a vehicle is described. The method includes measuring a vehicle center using a gauge. The gauge includes a carrier section from which a pair of arms extend in opposed directions. Each of the arms has an axle center locator. The carrier section has a vehicle center marker. Upon determination of the vehicle center, the vehicle can be located in a wind tunnel at a predetermined location and exposed to an enhanced air flow.

Abstract: A wind tunnel balance, with a tunnel wall adaptor configured to fasten the wind tunnel balance to a wall of a wind tunnel, an actuator housing connected to the tunnel wall adaptor, a plurality of force sensors arranged between the actuator housing and the tunnel wall adaptor and which are configured to detect forces acting on the actuator housing, a pivot coupling, by means of which an airfoil model of an aircraft can be pivotably coupled to the actuator housing, and a plurality of piezoelectric actuators arranged in the actuator housing and which are configured to controllably deflect an airfoil model mounted on the pivot coupling in three spatial directions.

Abstract: The invention relates to a wind tunnel balance, having at least one belt unit that has at least one belt unit frame equipped with at least one conveyor belt that is wound around at least two rollers. The wind tunnel balance also has at least one fastening device that is suitable for fastening a vehicle to the conveyor belt in a predetermined position, a frame, and a platform that is supported so that it is able to move relative to the frame; force measuring elements are provided between the platform and the frame and are able to detect forces between the frame and platform, and the fastening device is attached to the platform in stationary fashion. The invention permits a high-precision detection of aerodynamic forces in wind tunnel measurements or tests.

Abstract: A model motion system for providing controlled motion of a vehicle model with wheels on is provided. The model motion system includes a pitch system coupled to the vehicle model with wheels on to control a pitch range of motion of the vehicle; a roll system coupled to the vehicle model with wheels on to control a roll range of motion of the vehicle; and a yaw system coupled to the vehicle model with wheels on to control a yaw range of motion of the vehicle. The pitch system, the roll system, and the yaw system control the respective ranges of motion of the vehicle model with wheels on.

Abstract: An apparatus for testing an implement having an elongate shaft with a head end and a grip end, with a head attached to the head end. The apparatus may include a wind tunnel with a test cell adapted to receive the head of the implement and permit a range of unrestricted movement of the head within the test cell. The test cell includes an inlet and outlet for air flow and a portal or opening in a wall of the cell to which an elongate conduit is attached. The conduit extends in a direction substantially normal, or radial, to the direction of airflow. The conduit is adapted to receive the shaft of the implement, with the grip end of the implement extending beyond the far end of the conduit and into a clamp. The clamp is adapted to hold the grip end of the shaft in a fixed position.

Abstract: A method for removing interference-induced distortion effects from an environment used to experimentally measure aerodynamic signatures. A space marching algorithm is used to extract the effects of environment including rail and wall reflections and rail edge effects to create an interference-free pressure signature.

Abstract: A force measuring system is provided for measuring forces on a rotating body that includes, but is not limited to a force measuring device, which is mounted on the rotating body, as well as a position sensing unit for detecting the rotation of the rotating body and an evaluation unit, which is connected to the force measuring device and the position sensing unit. The evaluation unit is configured for recording a force value measured by the force measuring device depending on the detected position of the rotating body. The force measuring system allows the forces and torques on a rotating body to be determined precisely and as flexibly as possible, independently of the prevailing rotation speed of the rotating body.

Abstract: An engine simulator for wind tunnel models exhibits a turbine with an inlet for a pressurized fluid and an outlet for a relieved fluid, a flow-type body arranged downstream from the turbine, a jacket that at least partially envelops the flow-type body with the formation of a gap, and at least two electrodes. A downstream end of the flow-type body is provided with a heater coating comprised of a matrix material that contains a conductivity additive and is connected with the electrodes for applying an electrical voltage. This may make it possible to prevent ice formation on the trailing edge of the flow-type body.

Abstract: An open area platform for supplementing operation of a wind tunnel balance, comprises a platform body and platform adapters. The platform adapter members have first ends and second ends. The first ends are configured to contact the platform body and the second ends are designed to be operatively coupled with the wind tunnel's balance. As a result, any load on the platform body is configured to be transmitted through the platform adapter members and measured by the wind tunnel balance. Methods of using the open area platform, including for the testing of athletes and their equipment, are also disclosed.

Abstract: An example vane arm testing rig includes a base having a first attachment configured to receive a first end of a vane arm when the vane arm is in an engaged position, and a torque member having a second attachment configured to receive an opposing, second end of the vane arm when the vane arm is in the engaged position. The vane arm extends along a longitudinal axis from the first end to the second end. The first and second attachments are configured to rotate relative to each other about the axis. The first and second attachments are configured to move laterally relative to each other.

Abstract: A system and method for producing surface deformations on a surface of a body. The system and method relate to changing the convective heat transfer coefficient for a surface. The system includes a first surface being a surface of a body exposed to a fluid flow and at least one actuator affecting deformation of the first surface. The system also includes a control system providing control commands to the at least one actuator, the control commands configured to change deformations on the first surface in order to change the convective heat transfer coefficient of the first surface. Further, the system includes a sensor providing environmental characteristic information to the control system.

Abstract: There is provided a wind tunnel model measuring system for use with a wind tunnel. The system has a measuring assembly with an automated movable structure with at least one measuring device mounted thereon and configured for placement within the wind tunnel, and a measuring controller device located outside the wind tunnel to control the automated movable structure in order to remotely move the automated movable structure from a storage position within the wind tunnel to one or more operating positions with respect to a wind tunnel model within the wind tunnel and to allow the at least one measuring device to determine a relative position of at least one movable first component with respect to a second component, both of the wind tunnel model. The system further has a processing device configured for placement outside the wind tunnel and coupled to the measuring controller device.

Abstract: A wind tunnel device defines a cyclical tunnel to receive continuous airflow. Airflow is delivered through the tunnel to a testing region that includes a first portion carrying an arm including a spray tip configured to spray particulates in the testing region at an angle, and a second portion including an enlarged cutout region configured to receive the angled sprayed particulates. As airflow carries the angled spray particulates into the second portion, the enlarged cutout region enables the spray particulates to pass through and exit the second portion of the testing region. Analysis in the second region may be conducted through transparent walls free of openings to minimize exposure of the spray particulates to the exterior of the device. A scrubber is adapted to extract spray mist from the airflow as the airflow exits the testing region and is re-circulated through the cyclical tunnel.

Abstract: A locking fastening device for fastening a first component to a second component, an adjustable fastening device for adjustably fastening a first component to a second component, and a component system including at least one first component that is fastened to a second component are described. Also described are a main wing of a wind tunnel model aircraft having an adjusting and fastening system which includes at least one locking fastening device and at least two adjustable fastening devices for adjusting and fastening an aerodynamic additional body that is adjustable relative to the main wing by means of a plurality of retaining devices, as well as a wind tunnel model aircraft having such a main wing.

Abstract: A method of optimizing performance of a wind turbine electric generator (WTG) comprises the steps of measuring the performance of a wind turbine electric generator, defining an area on a blade of the WTG, placing stall flags within said defined area, monitoring the behavior of the stall flags when the WTG is operating, determining a stall line based upon the stall flags during operation, installing vortex generators on the blade adjacent to and upwind of said stall line, monitoring the behavior of said stall flags during operation with vortex generators installed on all blades, and measuring the performance of the WTG to detect improved performance. If there is little or no improvement, repeating the steps on a second WTG using different placement within the defined area for the vortex generators.

Abstract: The invention relates to a flow state sensor (10) for detecting a flow state at a body (16) that may be impinged on by a flow (12). A flow state sensor (10) that is of a simple construction and that is simple to evaluate is characterized in accordance with the invention by at least one frequency detecting device (20) for detecting at least one predefined frequency characteristic of the flow state. The frequency detecting device (20) has at least one oscillation element (22; 22a, 22b, 22c) excitable to resonant oscillatory movement (30) by a flow (12) and having a resonant frequency or natural frequency adapted to the predefined frequency characteristic, especially corresponding to the predefined frequency characteristic. Uses of the flow state sensor (10) in a flow measuring device (62) and in a flow measuring method, and an advantageous production method for the flow state sensor (10) are also proposed.

Abstract: A wind tunnel with a closed section for aeroacoustic measurements with an anechoic coating including: a) a first cavity having a thickness D1 in a range of 20?D1?50 mm filled with a fibrous material with a flow resistance R in a range of 10?R?50 kRayl/m; b) a first microperforated panel having a thickness t1 in a range of 0.25?t1?0.75 mm and with a perforation percentage p1 in a range of 15%?p1?30%; c) a second air cavity having a thickness D2 in a range of 10?D2?30 mm; d) a second microperforated panel having a thickness t2 in a range of 0.25?t2?0.75 mm and with a perforation percentage p2 in a range of 15%?p2?30%. The perforations of the panels can be circular or longitudinal slot-shaped having a diameter d or width w in a range of 0.2?d, w?0.5 mm.

Abstract: A probe for measuring a local angle of attack designed to be fixed to a wall and a method implementing the probe are provided. The probe comprises at least three pressure sampling ports disposed over a nose of the probe body, pressure measurement means associated with the pressure sampling ports and calculation means capable of determining an angle of attack of the flow with respect to the main direction of the probe body as a function of the pressures measured by the pressure measurement means. The calculation means are configured for choosing from amongst the pressure sampling ports those allowing the best measurement precision of the local angle of attack to be obtained and for calculating the local angle of attack with respect to the main direction using the pressure measurements carried out in the chosen pressure sampling ports.

Abstract: A wind tunnel device defines a cyclical tunnel to receive continuous airflow. Airflow is delivered through the tunnel to a testing region that includes a first portion carrying an arm including a spray tip configured to spray particulates in the testing region at an angle, and a second portion including an enlarged cutout region configured to receive the angled sprayed particulates. As airflow carries the angled spray particulates into the second portion, the enlarged cutout region enables the spray particulates to pass through and exit the second portion of the testing region. Analysis in the second region may be conducted through transparent walls free of openings to minimize exposure of the spray particulates to the exterior of the device. A scrubber is adapted to extract spray mist from the airflow as the airflow exits the testing region and is re-circulated through the cyclical tunnel.

Abstract: A method for removing interference-induced distortion effects from an environment used to experimentally measure aerodynamic signatures. A space marching algorithm is used to extract the effects of environment including rail and wall reflections and rail edge effects to create an interference-free pressure signature.

Abstract: An apparatus for testing effects of relative movement of a fluid and an object has a test chamber (3) arranged to contain a fluid and is open in a manner to allow fluid inlet and/or outlet while the movable surface is moving. There is a drive (1) for moving a movable surface (13) with respect to the fluid in the chamber, and a probe for monitoring fluid conditions within the test chamber. The chamber has an inlet (5) and a separate outlet (6), and the drive is arranged to rotate a rotor (1) having the movable surface (13).

Abstract: A prank apparatus includes a base unit, a driving device and a decorative unit. The base unit includes a housing, a support rack, a sounder, a sensor, a power supply, and a control board. The driving includes a mounting seat, a drive wheel, a drive motor, a driven wheel, a support bar, and two torsion springs. The In the preferred embodiment, the decorative unit includes an extension shank having a first end connected with the support bar and a second end provided with a guide slot, a movable pin movably mounted in the guide slot, a first link having a first end pivotally connected with the movable pin, a decorative body connected with a second end of the first link, and a second link having a first end pivotally connected with the support rack and a second end pivotally connected with the first link.