Synchronized pre-impact and catapult accelerator system
Patent Information
- Application Number
- EP2024808076
- Authority / Receiving Office
- EP · EP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2023-05-16
- Filing Date
- 2024-05-16
- Publication Date
- 2026-02-25
Smart Images
Figure US2024029629_21112024_PF_FP_ABST
Abstract
Description
SYNCHRONIZED PRE-IMPACT AND CATAPULT ACCELERATORSYSTEMCROSS REFERE CE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Patent Application Serial No. 63 / 502,472, filed May 16, 2023. Application Serial No. 63 / 502,472 is fully incorporated herein by reference.BACKGROUND
[0002] Vehicle impact safety is assessed at crash test facilities. Some crash tests are performed in such facilities using a catapult accelerator system. Commercially available catapult accelerator systems are designed to accelerate a payload to reproduce a vehicle collision acceleration versus time profile. These systems are used, frequently with crash dummies, to assess occupant injury during a collision to improve vehicle crashworthiness.
[0003] Existing catapult accelerator systems reproduce the high accelerations (typically above 20 g of acceleration), short impact distance (typically within 2 meters), and short time (about 150 milliseconds) of typical vehicle collisions. They include a test platform that is rail-guided in the axis of acceleration. Various test specimens, such as a car frame fitted with dummies and restraint systems, are attached to the test platform as a payload. Catapult accelerators launch the test platform (with the payload) from zero velocity to a final velocity to match a collision acceleration profile.
[0004] Prior to a real collision, the driver or vehicle safety systems may apply the vehicle brakes. This pre-impact braking can last several seconds, with negative acceleration at the limit of typical car tire friction capability, which can be up to 2 g. As compared to the collision itself, this pre-impact acceleration is much lower and occurs over a greater distance. In this pre-impact interval, other safety restraint systems may activate, and the occupants move due to the force of acceleration. Existing catapult accelerators have limited ability to reproduce both a long duration, low acceleration pre-impact acceleration profile and a short duration, high acceleration collision acceleration profile within the same test cycle.BRIEF DESCRIPTION OF THE DRAWINGS
[0005] FIG. 1 illustrates an example synchronized pre-impact and catapult accelerator system in operation at various stages throughout an example test cycle.
[0006] FIG. 2 illustrates an example acceleration profile reproduced during a test performedusing the synchronized pre-impact and catapult accelerator system.
[0007] FIG. 3 illustrates example components of a pre-impact accelerator of the system depicted in FIG. 1.
[0008] FIG. 4 illustrates an example linear position transducer and friction damper of the system depicted in FIG. 1.
[0009] FIG. 5 illustrates an example release mechanism that allows the test platform to decouple from the pre-impact accelerator prior to the catapult accelerator applying a modulated force to the test platform.
[0010] FIG. 6 is a block diagram of an example architecture of a system in accordance with various embodiments.DETAILED DESCRIPTION
[0011] As mentioned above, existing catapult accelerators have limited ability to reproduce both a long duration, low acceleration pre-impact acceleration profile and a short duration, high acceleration collision acceleration profde within the same test cycle. Disclosed herein are, among other things, techniques, devices, and systems for integrating a long distance, low force pre-impact accelerator and a short distance, high force catapult accelerator into a synchronized pre-impact and catapult accelerator system.
[0012] The pre-impact accelerator of the disclosed system is configured to reproduce a preimpact acceleration profile typical of hard braking just before a collision occurs. This pre-impact acceleration profile may be a long distance, low force acceleration profile that mimics vehicle behavior just before a collision. For example, a driver or a vehicle safety system of a vehicle may apply the vehicle brakes just before a collision, and such pre-impact braking can last several seconds, with much lower acceleration over a greater distance, as compared to the collision.
[0013] The catapult accelerator of the disclosed system is configured to reproduce a collision acceleration profile typical of a collision. This collision acceleration profile may be a short distance, high force acceleration profile with much higher acceleration, as compared to the preimpact acceleration profile. By integrating the pre-impact accelerator and the catapult accelerator into the synchronized pre-impact and catapult accelerator system described herein, both pre-impact and collision acceleration profiles can be reproduced sequentially in a single test cycle, which enhances crash testing by, for instance, mimicking the realism of a scenario of a vehicle crash that would otherwise be irreproducible by existing catapult accelerators. The analysis results of such enhanced crash testing can be leveraged for further development of vehicle safety systems that improve vehicle safety.
[0014] A test cycle of a test performed using the disclosed system starts with a payload coupled to a top surface of a test platform, and with the test platform positioned at an end of a track opposite the catapult accelerator. For example, the track may have a first end and a second end opposite the first end, with the catapult accelerator positioned at the first end of the track, and with the test platform positioned at the second end of the track at the beginning of the test cycle. The preimpact accelerator, which is coupled to the test platform, applies a first modulated force to the test platform in a first direction to accelerate the test platform towards the first end of the track (e.g., towards the catapult accelerator). The test platform is accelerated until sensor data indicates that the velocity of the test platform has reached a target velocity within a predefined distance of travel, as determined (e.g., calculated) by a control system. The pre-impact accelerator or a brake(s) then applies a second modulated force to the test platform in a second direction opposite the first direction to decelerate the test platform. The application of the second modulated force to the test platform reproduces a pre-impact acceleration profile. In this pre-impact interval, the acceleration of the test platform is calculated and controlled such that the velocity of the test platform is approximately zero velocity at or near a pushing surface disposed on or adjacent to an end of the catapult accelerator that faces the approaching test platform. Based on transducer data generated by a linear position transducer, the catapult accelerator, the pre-impact accelerator, or both accelerators move to bring the test platform and the pushing surface into contact with their velocities substantially matched. The substantially matched velocities at contact may be in the first direction, or zero, or in the second direction. The catapult accelerator then reproduces the collision acceleration profile by applying a third modulated force to the test platform in the second direction to accelerate the test platform towards the second end of the track, thereby creating a large acceleration spike typical of a collision.
[0015] The techniques, devices, and systems described herein synchronize the application of forces to the test platform from the pre-impact accelerator and the catapult accelerator. An advantage of synchronizing the two accelerators in this way is that each accelerator is optimized for a very different acceleration profile than the other. That is, the pre-impact accelerator is optimized for a pre-impact acceleration profile typical of pre-impact braking, and the catapult accelerator is optimized for a collision acceleration profile typical of a collision itself. The resultant acceleration profile that is reproduced by the two accelerators during a single test cycle is a long distance, low force acceleration portion of the profile followed by a short distance, high force portion of the profile. Moreover, an advantage of a velocity reversal of the test platform between pre-impact and collision reproduction is lower system velocity.
[0016] Also disclosed herein are processes, as well as systems comprising one or more processors and one or more memories (e.g., non-transitory computer-readable media) storingcomputer-executable instructions that, when executed by the one or more processors, perform various acts and / or processes disclosed herein. The techniques, devices, and systems will now be described in detail with reference to figures.
[0017] FIG. 1 illustrates an example synchronized pre-impact and catapult accelerator system 100 in operation at various stages throughout an example test cycle 102. The system 100 may include a track 104, a test platform 106, a pre-impact accelerator 108, a catapult accelerator 110, a pushing surface 112, and one or more sensors 114, among other components. The track 104 has a first end 116(1) and a second end 116(2) opposite the first end 116(1). The track 104 can be straight, and may have one or more guide rails that allow one or more movable components of the system 100 to move along the track 104. For example, the test platform 106 is movable along the track 104, and the pushing surface 112 may also be movable along the track 104, in some examples. The movable component(s) (e.g., the test platform 106 and, in some examples, the pushing surface 112) can be moved bidirectionally along the track 104. For example, the test platform 106 and the pushing surface 112 are each movable (e.g., independently of one another) in a first direction 118(1) towards the first end 116(1 ) of the track 104, and in a second direction 118(2) towards the second end 116(2) of the track 104, the second direction 118(2) being opposite the first direction 118(1).
[0018] The pre-impact accelerator 108 is configured to apply a modulated force to the test platform 106 at least in the first direction 118(1). In some examples, and the pre-impact accelerator 108 is configured to apply modulated forces to the test platform 106 bidirectionally. For example, the pre-impact accelerator 108 may be configured to apply a modulated force to the test platform 106 in the first direction 118(1), and subsequently apply a modulated force to the test platform 106 in the second direction 118(2) to reproduce a pre-impact acceleration profile. In some examples, the pre-impact accelerator 108 includes, among other components, an engine and a force transmission apparatus to apply these modulated forces to the test platform 106. The engine and the force transmission apparatus will be described in more detail below with reference to FIG. 3. In some examples, a brake(s) may be used to decelerate the test platform 106 by applying a braking force in the second direction 118(2) after the pre-impact accelerator 108 accelerates the test platform 106 in the first direction 118(1). In some examples, the pre-impact accelerator 108 is configured to accelerate and decelerate the test platform 106 at a relatively low acceleration (e.g., at or below 2 g of acceleration).
[0019] The catapult accelerator 110 is configured to reproduce a collision acceleration profile by applying a modulated force to (e.g., pushing on) the test platform 106 via the pushing surface 112, which may be disposed on or adjacent to an end of the catapult accelerator 110 that faces the test platform 106. Accordingly, the pushing surface 112 is configured to applyacceleration forces (to the test platform 106) in the second direction 118(2). In this manner, the catapult accelerator 110 is configured to accelerate the test platform 106 in the second direction 118(2) towards the second end 116(2) of the track 104. In some examples, the catapult accelerator 110 includes a pressurized fluid-based actuator (e.g., a pneumatic actuator, a hydraulic actuator, etc.) to apply this modulated force to the test platform 106 via the pushing surface 112. In some examples, the catapult accelerator 110 is configured to accelerate the test platform 106 at a relatively high acceleration (e.g., at or above 20 g of acceleration).
[0020] The test platform 106 (which can also be referred to herein as a “sled”) is configured to receive (and withstand) the high forces applied by the catapult accelerator 110 to a side of the test platform 106 that is facing the catapult accelerator 110. The test platform 106 may have atop surface for supporting a payload 120 (which can also be referred to herein as a “test specimen” or a “test article”). The payload 120 can be one or more vehicle seats (e.g., a vehicle frame with seats) fitted with dummies and restraint systems (e.g., seatbelts, etc.), or any other suitable payload that is to be evaluated in a crash test. The top surface of the test platform 106 may be substantially flat so that the payload 120 can be set on top of the test platform 106 without falling off of the test platform 106, and the top surface of the test platform 106 may have mounting features (e.g., threaded holes configured to receive bolts, clamps, shear keys, latches, hooks, locks, etc.) to couple (e.g., affix) the payload 120 to the test platform 106 such that the payload 120 remains attached to the test platform 106 throughout the test cycle 102. In this manner, the test platform 106 is configured to transport the payload 120 along the track 104 when the payload 120 is coupled to the top surface of the test platform 106.
[0021] Both the pre-impact accelerator 108 and the catapult accelerator 110 (and / or systems associated with these accelerators 108, 110) are controlled by a computerized control system that modulates the forces applied by the accelerators 108, 110 based on a time series of parameters that are calculated to reproduce both the pre-impact and collision acceleration profiles, making closed- loop correction based on sensor inputs (e.g., sensor data generated by one or more of the sensors 114). An example system 600 that may be used as the aforementioned computerized control system is described in more detail below with respect to FIG. 6. The pre-impact accelerator 108 and the catapult accelerator 110 are configured to operate in synchronization over the duration of the test cycle 102 to produce a complete reproduction of both the pre-impact and collision acceleration profiles. This will now be described with reference to the sequential steps of the example test cycle 102 shown in FIG. 1.
[0022] The processes described in this disclosure may be implemented by the architectures described herein, or by other architectures. These processes can be implemented in hardware, software, or a combination thereof. In the context of software, the described operations mayrepresent computer-executable instructions stored on one or more computer-readable storage media that, when executed by one or more processors, perform the recited operations. Generally, computer-executable instructions include routines, programs, objects, components, data structures, and the like that perform particular functions or implement particular abstract data types. The order in which the operations are described is not intended to be construed as a limitation, and any number of the described operations can be combined in any order or in parallel to implement the processes. It is understood that the following processes may be implemented on other architectures as well.
[0023] At Step 1 of the test cycle 102, an operator of the system 100 may input the desired pre-impact and collision acceleration profile to a program executing on a user computing device. In this manner, the control system may receive, based on user input provided via a user interface presented on the user computing device, acceleration profile data indicative of a pre-impact acceleration profile and a collision acceleration profile. The control system calculates a time series of force parameters, acceleration parameters, velocity parameters, and / or distance parameters for performing the test. The operator positions the test platform 106 at the second end 116(2) of the track 104 and couples (e.g., affixes) the payload 120 to the top surface of the test platform 106. The catapult accelerator 110 is prepared to apply the collision acceleration profile upon command from the control system.
[0024] At Step 2 of the test cycle 102, the control system controls the pre-impact accelerator 108 to apply a first modulated force 122(1) to the test platform 106 in the first direction 118(1), thereby accelerating the test platform 106 towards the first end 116(1) of the track 104, increasing the velocity of the test platform 106 from zero to a target velocity (e.g., 24 kilometers per hour (kph)) within a predefined distance of travel (e.g., 10.5 meters (m)). This acceleration is preferably low (e.g., at or below 0.5 g of acceleration) to minimize disturbing the payload 120.
[0025] At Step 3 of the test cycle 102, in response to sensor data (e.g., generated by the sensor(s) 114) indicating that the velocity of the test platform 106 has reached the target velocity within the predefined distance of travel along the track 104, the control system controls the preimpact accelerator 108 or a brake(s) to apply a second modulated force 122(2) to the test platform 106 in the second direction 118(2) to reproduce the desired pre-impact acceleration profile, decreasing the velocity of (e.g., decelerating) the test platform 106 at a rate calculated by the control system until the velocity of the test platform 106 reaches approximately zero velocity at or near the pushing surface 112, or until movement of the test platform 106 reverses such that the test platform 106 is moving in the second direction 118(2) at a low velocity when the test platform 106 is in close proximity to the pushing surface 112. In some examples, the secondmodulated force 122(2) is applied at a time when the test platform 106 moves to a position on the track 104 that is within a predefined distance of the pushing surface 112, such as 2.8 m from the pushing surface 112.
[0026] At Step 4 of the test cycle 102, the pushing surface 112 and the test platform 106 are shown to be in contact with each other prior to the transition from the pre-impact acceleration profile to the collision acceleration profile. Various modes of operation are contemplated for implementing this transition. In a first mode of operation (e.g., a “stop-touch-then-fire” mode), the test platform 106 makes contact with (e g., touches), or moves into close proximity to, the pushing surface 112 at a time when the velocity of the test platform 106 reaches approximately zero velocity due to the deceleration of the test platform 106 at Step 3. In a second mode of operation (e.g., a “reverse-direction-touch-then-fire” mode), the velocity of the test platform 106 (and the direction of travel of the test platform 106) reverses near the pushing surface 112 due to continued application of the second modulated force 122(2) to the test platform 106, thereby causing the test platform 106 to start moving in the second direction 118(2), and the control system then controls the catapult accelerator 110 to move the pushing surface 112 into contact with the test platform 106 while the test platform 106 is moving in the second direction 118(2). In a third mode of operation (e.g., a “touch-reverse-direction-then-fire” mode), the test platform 106 makes contact with (e.g., touches), or moves into close proximity to, the pushing surface 112 at a time when the pushing surface 112 and the test platform 106 are moving in the first direction 118(1). After contact is made, the pushing surface 112 and the test platform 106 may continue to move in the first direction 118(1) or may move in the second direction 118(2) before applying the third modulated force 122(3) in the second direction 118(2). . It is to be appreciated that the direction of force on (and therefore the acceleration on) the test platform 106 is away from the first end 116(1) throughout the pre-impact braking interval, whereby the velocity of the test platform 106 can, but does not have to, reverse, yet the force vector does not. In some examples, the movement of the pushing surface 112 and / or the movement of the test platform 106 is / are controlled in order to substantially match the velocity of the pushing surface 112 to the velocity of the test platform 106 just as the pushing surface 112 makes contact with the test platform 106, which prevents a significant impact (abrupt change in velocity) that might disturb the payload 120. In some examples, the catapult accelerator 110 is controlled to move the pushing surface 112 into contact with the test platform 106 based on transducer data generated by a linear position transducer (See FIG. 4 for a more detailed description of an example linear position transducer 400). For example, the transducer data may indicate that the pushing surface 112 is spaced a distance from the test platform 106 around the time when the velocity of the test platform 106 reaches approximately zero velocity at or near the pushing surface 112 (within the sensing envelope of the linear positiontransducer 400), and the catapult accelerator 110 may be controlled to move the pushing surface 112 and / or the pre-impact accelerator 108 may be controlled to move the test platform 106 by a certain amount(s) in order to close that distance and to establish contact between the pushing surface 112 and the test platform 106.
[0027] In some examples, a smoothing mechanism (e.g., a damper, a crushable sheet, and / or the like) may be disposed between the pushing surface 112 and the test platform 106. This smoothing mechanism may be used to smooth the transition from the pre-impact accelerator 108 to the catapult accelerator 110, thereby reducing possible acceleration spikes as the test platform 106 and the pushing surface 112 are brought into contact. For example, the test platform 106 and the pushing surface 112 may be made of a rigid, or at least a semi-ngid, material, and the smoothing mechanism may help to absorb some of that impact to smooth the aforementioned transition. The stroke of the smoothing mechanism may be limited in order to smooth the transition from the pre-impact accelerator 108 and the catapult accelerator 110, and, in the fully actuated or crushed state, the smoothing mechanism and / or other contact surface will transmit the high forces associated with the collision acceleration profile to the test platform 106. In some examples, a damper used as the smoothing mechanism is implemented as a friction device (e.g., a friction damper) with force set by varying the normal force on a sliding surface. An example material for a crushable sheet that is used as the smoothing mechanism is aluminum honeycomb.
[0028] At Step 5 of the test cycle 102, once the pushing surface 112 has contacted the test platform 106 or is in close proximity thereto, the control system controls the catapult accelerator 110 to apply, via the pushing surface 112, a third modulated force 122(3) to the test platform 106 in the second direction 118(2), thereby accelerating the test platform 106 towards the second end 116(2) of the track 104. As mentioned, this acceleration is preferably high (e.g., at or above 20 g of acceleration) to reproduce the collision acceleration profile. Accordingly, the third modulated force 122(3) is greater than the first modulated force 122(1) and the second modulated force 122(2). In some examples, the third modulated force 122(3) is applied in response to transducer data (generated by the linear position transducer 400) indicating that the pushing surface 112 has contacted the test platform 106.
[0029] To enable the required timing and velocity precision, the pre-impact accelerator 108 can be fitted with one or more sensors 114, as mentioned above. The sensor(s) 114 is / are configured to measure, over the full stroke of the test platform 106, the acceleration, velocity, and / or position of the test platform 106 on the track 104. The control system uses the sensor data generated by the sensor(s) 114 for closed-loop control of the pre-impact accelerator 108, thereby controlling the acceleration, velocity, and / or position of the test platform 106 in real-time. In other words, the control sy stem may adjust the first modulated force 122(1) and / or the second modulatedforce 122(2) in real-time during the test cycle 102 based on the sensor data generated by the sensor(s) 114 and in accordance with a pre-impact acceleration profde specified by the operator. In some examples, the catapult accelerator 110 may be fitted with similar sensors so that the control system can adjust the third modulated force 122(3) in real-time during the test cycle 102 based on the sensor data and in accordance with a collision acceleration profile specified by the operator.
[0030] FIG. 2 illustrates an example acceleration profile 200 reproduced during a test performed using the synchronized pre-impact and catapult accelerator system 100. The acceleration profile 200 is a curve that represents the acceleration of the test platform 106 over time throughout a single test cycle 102. The encircled numbers 1 through 5 in FIG. 2 represent time intervals or points in time associated with the sequential steps (1 through 5) of the test cycle 102 described above with reference to FIG. 1. As can be seen in FIG. 2, the test platform 106 is initially at rest at Step 1 of the test cycle 102.
[0031] At Step 2 of the test cycle 102, the test platform 106 is accelerated, thereby increasing the velocity of the test platform 106 to a target velocity within a predefined distance of travel. The acceleration during the time interval associated with the encircled number 2 in FIG. 2 is preferably low (e.g., at or below 0.5 g of acceleration).
[0032] At Step 3 of the test cycle 102, the test platform 106 is decelerated, thereby decreasing the velocity of the test platform 106 at a rate calculated by the control system until the velocity of the test platform 106 reaches approximately zero velocity in close proximity to the pushing surface 112 or just as the test platform 106 makes contact with (e.g., touches) the pushing surface 112. This negative acceleration during the time interval associated with the encircled number 3 in FIG. 2 is also preferably low (e.g., at or below 2 g of acceleration).
[0033] At Step 4 of the test cycle 102, the pushing surface 112 is in contact with the test platform 106. Prior to this contact being made, the catapult accelerator 110 may be actuated to move the pushing surface 112 into contact with the test platform 106, and the direction of travel can be in the first direction 118(1), at rest, or in the second direction 118(2). In some examples, movement of the pushing surface 112 and / or movement of the test platform 106 is controlled to substantially match the velocity of the pushing surface 112 to the velocity of the test platform 106 just as the pushing surface 112 makes contact with the test platform 106.
[0034] At Step 5 of the test cycle 102, the test platform 106 is accelerated in the second direction 118(2) by the catapult accelerator 110 applying a modulated force to the test platform 106 via the pushing surface 112, thereby accelerating the test platform 106 towards the second end 116(2) of the track 104. As mentioned, this acceleration during the time interval associated with the encircled number 5 in FIG. 2 is preferably high (e g., at or above 20 g of acceleration) to reproduce the collision acceleration profile.
[0035] FIG. 3 illustrates example components of the pre-impact accelerator 108. In some examples, the test platform 106 is actuated by force transmitted from an engine 302 by means of a force transmission apparatus. The force transmission apparatus may be comprised of an axially stiff rope 304 that is coupled (e.g., affixed) to the test platform 106, forming a loop that is routed over sheaves and a capstan 306. The capstan 306 has multiple helical wraps of rope 304 sufficient to prevent slippage, and the pitch of the helical wraps of rope 304 follow a spiral groove on the capstan 306. A threaded rod 308 with the same pitch as the spiral groove on the capstan 306 is coupled (e.g., affixed) to a shaft of the capstan 306 and engages a nut 310 mounted to the ground. The assembly of the engine 302, the capstan 306, and the threaded rod 308 is mounted on linear bearings 312 to move together with respect to ground. By this configuration, rotation of the engine 302 effects a lateral movement of the capstan 306, and the helical wraps of rope 304 remain laterally stati onary. A tensioner 314 sufficiently tensions the rope 304 to maintain rope tension and prevent capstan 306 slippage. During operation, a position of the tensioner 314 is locked so that the resulting loop of rope 304 has a fixed route and so that the capstan 306 may impart force to the rope 304 in either direction with a stiff force connection to the test platform 106. The engine 302 is controlled by a variable speed drive 316. The variable speed drive 316 and the engine 302 may be selected to have low mass and high frequency response to maximize controllability via the computerized control system. The engine 302 or the capstan 306 rotating assembly is fitted with a sensor 114 (e.g., an encoder) for measuring the position of the test platform 106. This position measurement (e.g., sensor data indicating the position measurement) can be used by the computerized control system as an input from which the position of the test platform 106 on the track 104, the velocity of the test platform 106, and / or the acceleration of the test platform 106 may be derived. In this way, test platform 106 motion can be controlled throughout the pre-impact acceleration imparted by the pre-impact accelerator 108.
[0036] FIG. 4 illustrates an example linear position transducer 400 and friction damper 402 of the synchronized pre-impact and catapult accelerator system 100. As the test platform 106 comes into close proximity of the pushing surface 112, an accurate and precise measurement(s) of the relative position, velocity, and / or acceleration of the test platform 106 and the pushing surface 112 can be used to effect a smooth transition from the pre-impact accelerator 108 to the catapult accelerator 110. In some examples, this measurement(s) can be made by a spring-loaded linear position transducer 400 fitted to either the pushing surface 112 or the test platform 106. The computerized control system uses transducer data generated by this linear position transducer 400 to calculate relative position, velocity, and / or acceleration of the test platform 106 and the pushing surface 112 for use in a feedback loop during the transition from the pre-impact accelerator 108 to the catapult accelerator 110. Once the test platform 106 contacts the pushing surface 112 (whichcan be disposed on an end of the catapult accelerator 110 that faces the approaching test platform 106), the pushing surface 112 and the test platform 106 are moved as one (e.g., in unison) as the control system controls the catapult accelerator 110 to reproduce the collision, with acceleration of the collision acceleration profile measured by an accelerometer fitted to the pushing surface 112, the test platform 106, or both.
[0037] The pushing surface 112 and the test platform 106 may be rigid and strong to transmit the large and rapidly varying forces generated by the catapult accelerator 110. As contact is made between the pushing surface 112 and the test platform 106, a relative velocity and / or an acceleration spike due to impact can result. As shown in FIG. 4, a short-stroke friction damper 402 can be fitted so that the pushing surface 112 applies force to the test platform 106 in the second direction 118(2) some distance before contact is made. The friction damper 402, which can be a plate(s) in some examples, may be coupled (e.g., affixed) to either the pushing surface 112 or the test platform 106 in such a way that the friction damper 402 (e.g., plate(s)) can slide against the mounting surface for a set distance until contact is made between the pushing surface 112 and the test platform 106. The pre-load of the friction damper attachment (e.g., plate attachment) allows regulation of the friction force, and the initial position of the friction damper 402 (e.g., plate(s)) sets the damping stroke. By these means, a known force and energy are applied in the second direction 118(2) from the pushing surface 112 to the test platform 106 as the velocities are substantially matched, softening potential impact.
[0038] FIG. 5 illustrates an example release mechanism 500 that allows the test platform 106 to decouple from the pre-impact accelerator 108 prior to the catapult accelerator 110 applying a modulated force to the test platform 106. The collision acceleration profile (See e.g., the time interval associated with the encircled number 5 in FIG. 2) typically has acceleration and velocity much higher than the pre-impact acceleration profile (See e.g., the time interval associated with the encircled number 3 in FIG. 2). Partly or completely releasing the test platform 106 from the pre-impact accelerator 108 is advantageous to prevent exposing the pre-impact accelerator 108 to these high forces and velocities, thereby preventing damage to the pre-impact accelerator 108. Examples of devices to achieve this decoupling include the release mechanism 500 depicted in FIG. 5 to release the test platform 106 from the drive rope 304, a clutch to disconnect engine 302 of the pre-impact accelerator 108 from the rest of the pre-impact accelerator 108 system, and / or a force-limiting breakaway device, such as a shear pin that disconnects the test platform 106 from the pre- impact accelerator 108 once the force from the catapult accelerator 110 is applied.
[0039] With reference to the example release mechanism 500 shown in FIG. 5, the pre-impact accelerator rope loop is terminated at the release spool 502. The release spool 502 is latched to the release mechanism 500, which is coupled (e.g., affixed) to the test platform 106. When the releasespool 502 is latched to the release mechanism 500, forces can be applied bidirectionally (e.g., in the first direction 118(1) and in the second direction 118(2)) to the test platform 106 by the rope 304. A groove in the release spool 502 applies a force in the first direction 118(1) to a cam- actuated release lever 504 of the release mechanism 500, and a force in the second direction 118(2) is applied by a release spool flange 506. During the time that the force is applied in the second direction 118(2) and the test platform approaches the pushing surface 112, a cam 508 mounted to the ground actuates the release lever 504 and disengages the release mechanism 500 from the release spool 502, freeing the release mechanism 500 and the test platform 106 for motion of the test platform 106 in the second direction 118(2) during the operation of the catapult accelerator 110.
[0040] FIG. 6 is a block diagram of an example architecture of a system 600 in accordance with various embodiments. The system 600 may represent the aforementioned computerized control system that is used to control components of the system 100 introduced in FIG. 1, such as the accelerators 108 and 110. As shown, the system 600 may include one or more processors 602 and one or more forms of computer-readable memory 604. The system 600 may also include additional storage devices. Such additional storage may include removable storage 606 and / or non-removable storage 608.
[0041] In various embodiments, the computer-readable memory 604 is non-transitory and can include both volatile memory and non-volatile memory (e.g., random access memory (RAM), read-only memory (ROM), erasable programmable read-only memory (EEPROM), Flash Memory, miniature hard drive, memory card, optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium). The non-transitory computer-readable memory 604 may also be described as computer storage media and may include volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information, such as computer readable instructions, data structures, program modules, or other data. Computer-readable memoiy 604, as well as the removable storage 606 and non-removable storage 608, are all examples of non-transitory computer-readable storage media, and some or all of the memory 604, the removable storage 606, and / or the non-removable storage 608 may constitute the local memory of the system 600, as described herein. Non- transitory computer-readable storage media include, but are not limited to, random access memory (RAM), read-only memory (ROM), electrically erasable programmable ROM (EEPROM), flash memory or other memory technology, compact disc ROM (CD-ROM), digital versatile disks (DVD) or other optical storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired informationand which can be accessed by the system 600. Any such non-transitory computer-readable storage media may be part of the system 600.
[0042] The system 600 may further include one or more input devices 610, including, without limitation, a touch screen (e.g., touch, or proximity-based) display, physical buttons (e.g., keyboard or keypad), a camera-based sensor configured to receive gestural input from a user, a microphone or microphone array for receiving voice input commands from a user, pointing devices (e.g., mouse, pen, stylus, etc.), or any other suitable input devices 610 coupled communicatively to the processor(s) 602 and the computer-readable memory 604. The system 600 may further include one or more output devices 612, including, without limitation, a display, one or more light-emitting diode (LED) indicators, speakers, a printer, or any other suitable output device coupled communicatively to the processor(s) 602 and the computer-readable memory 604.
[0043] The system 600 may further include communications interface(s) 614 that allow the system 600 to communicate with other computing devices 616 such as via a network (e.g., a wired network, a cellular network, a radio air interface, etc.), which can be a local area network(s) and / or a wide area network(s). The communications interface(s) 614 may facilitate transmitting and receiving signals over any suitable wireless and / or wireline communications interface(s). In an example, the system 600 may communicate with (e.g., receive data from and / or send data to) the aforementioned sensors(s) 114 and / or the aforementioned linear position transducer 400 via the communications interface(s) 614. As another example, the system 600 may communicate with (e.g., receive data from and / or send data to) systems associated with the aforementioned accelerators 108, 110).
[0044] In some embodiments, the computer-readable memory 604 may include a control component 618, which represents computer-executable instructions stored in the memory 604 and executable by the processors) 602 to perform the operations described herein. For example, the control component 618 may be configured to control the pre-impact accelerator 108 and the catapult accelerator 110 (or the systems associated with these accelerators 108, 110), as described herein. The memory 604 may also store data, such as acceleration profile data 620, sensor data 622, and / or transducer data 624. For example, the acceleration profile data 620 may be indicative of a pre-impact acceleration profile and / or a collision acceleration profile, as described herein. For instance, if an operator of the system 100 provides user input, via the input device(s) 610, in order to input a desired pre-impact acceleration profile and a desired collision acceleration profile for an upcoming test, these profiles may be stored as acceleration profile data 620. Additionally, or alternatively, the acceleration profile data 620 may represent parameters calculated by the system 600 (e.g., by the control component 618) based on the aforementioned acceleration profiles, such as a time series of force parameters, acceleration parameters, velocity parameters, and / or distanceparameters for performing the test. In addition, as the sensor(s) 114 measure one or more of an acceleration of the test platform 106, a velocity of the test platform 106, or a position of the test platform 106 on the track 104, sensor data 622 may be generated and stored in the memory 604. Similarly, as the linear position transducer 400 measures one or more of the position of the test platform 106 relative to a position of the pushing surface 112, the velocity of the test platform 106 relative to a velocity of the pushing surface 112, or the acceleration of the test platform 106 relative to an acceleration of the pushing surface 112, transducer data 624 may be generated and stored in the memory 604. The data 620, 622, and / or 624 may be used in the performance of the operations, as described elsewhere herein.
[0045] Unless otherwise indicated, all numbers expressing quantities, properties, conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present disclosure. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. When further clarity is required, the term “about” has the meaning reasonably ascribed to it by a person skilled in the art when used in conjunction with a stated numerical value or range, i.e. denoting somewhat more or somewhat less than the stated value or range, to within a range of ±20% of the stated value; ±19% of the stated value; ±18% of the stated value; ±17% of the stated value; ±16% of the stated value; ±15% of the stated value; ±14% of the stated value; ±13% of the stated value; ±12% of the stated value; ±11% of the stated value; ±10% of the stated value; ±9% of the stated value; ±8% of the stated value; ±7% of the stated value; ±6% of the stated value; ±5% of the stated value; ±4% of the stated value; ±3% of the stated value; ±2% of the stated value; or ±1% of the stated value.
[0046] While the foregoing invention is described with respect to the specific examples, it is to be understood that the scope of the invention is not limited to these specific examples. Since other modifications and changes varied to fit particular operating requirements and environments will be apparent to those skilled in the art, the invention is not considered limited to the example chosen for purposes of disclosure, and covers all changes and modifications which do not constitute departures from the true spirit and scope of this invention.
[0047] Although the application describes embodiments having specific structural features and / or methodological acts, it is to be understood that the claims are not necessarily limited to the specific features or acts described. Rather, the specific features and acts are merely illustrative some embodiments that fall within the scope of the claims of the application.
Claims
CLAIMSWhat is claimed is:
1. A system comprising: a track having a first end and a second end opposite the first end; a test platform that is movable along the track and configured to transport a payload that is coupled to a top surface of the test platform; one or more sensors configured to generate, at one or more times during a test cycle, sensor data indicative of one or more of an acceleration of the test platform, a velocity of the test platform, or a position of the test platform on the track; a pre-impact accelerator coupled to the test platform and configured to accelerate the test platform at least in a first direction towards the first end of the track; a catapult accelerator positioned at the first end of the track and configured to accelerate the test platform in a second direction towards the second end of the track; a pushing surface that is configured to apply acceleration forces in the second direction, wherein the pushing surface is disposed on or adjacent to an end of the catapult accelerator that faces the test platform; and a control system configured to perform operations during the test cycle, wherein the test cycle starts with the test platform positioned at the second end of the track and having the payload coupled to the top surface of the test platform, the operations comprising: controlling the pre-impact accelerator to apply a first modulated force to the test platform in the first direction to accelerate the test platform towards the first end of the track; in response to the sensor data indicating that the velocity of the test platform has reached a target velocity within a predefined distance of travel along the track, controlling the pre-impact accelerator or a brake to apply a second modulated force to the test platform in the second direction to decelerate the test platform; and controlling the catapult accelerator to apply, via the pushing surface, a third modulated force to the test platform in the second direction to accelerate the test platform towards the second end of the track.
2. The system of claim 1, further comprising a linear position transducer configured to generate transducer data indicative of one or more of the position of the test platform relative to a position of the pushing surface, the velocity of the test platform relative to a velocity of the pushingsurface, or the acceleration of the test platform relative to an acceleration of the pushing surface, wherein the operations further comprise: based on the transducer data indicating that the pushing surface is spaced a distance from the test platform after the test platform has decelerated, controlling the catapult accelerator and / or the pre-impact accelerator to move the pushing surface and / or the test platform until the pushing surface contacts the test platform.
3. The system of claim 2, wherein the velocity of the test platform substantially matches the velocity of the pushing surface at a time when the pushing surface contacts the test platform.
4. The system of claim 1, wherein the pre-impact accelerator comprises an engine and a force transmission apparatus configured to apply the first modulated force and the second modulated force to the test platform.
5. The system of claim 1, wherein the third modulated force is greater than the first modulated force and the second modulated force.
6. The system of claim 1, wherein the pre-impact accelerator is coupled to the test platform via a release mechanism to allow the test platform to decouple from the pre-impact accelerator prior to the catapult accelerator applying the third modulated force to the test platform.
7. The system of claim 1, the operations further comprising adjusting at least one of the first modulated force or the second modulated force in real-time during the test cycle based on the sensor data in accordance with a pre-impact acceleration profile.
8. The system of claim 2, wherein the test platform is moving in the first direction, is at rest, or is moving in the second direction before the pushing surface contacts the test platform and the catapult accelerator applies the third modulated force to the test platform.
9. The system of claim 1, further comprising a friction damper coupled to the pushing surface or the test platform and configured to absorb the third modulated force.
10. The system of claim 1, wherein the payload comprises one or more vehicle seats fitted with dummies and restraint systems, and wherein the test cycle is associated with a vehicle crash test.
11. A method comprising: controlling a pre-impact accelerator to apply a first modulated force to a test platform in a first direction to accelerate the test platform towards a first end of a track, the test platform having a pay load coupled to a top surface of the test platform; in response to sensor data indicating that a velocity of the test platform has reached a target velocity within a predefined distance of travel along the track, controlling the pre-impact accelerator or a brake to apply a second modulated force to the test platform in a second direction opposite the first direction to decelerate the test platform; and controlling a catapult accelerator to apply, via a pushing surface, a third modulated force to the test platform in the second direction to accelerate the test platform towards a second end of the track opposite the first end of the track.
12. The method of claim 11, further comprising, based on transducer data indicating that the pushing surface is spaced a distance from the test platform after the test platform has decelerated, controlling the catapult accelerator and / or the pre-impact accelerator to move the pushing surface and / or the test platform until the pushing surface contacts the test platform.
13. The method of claim 12, wherein the velocity of the test platform substantially matches a velocity of the pushing surface at a time when the pushing surface contacts the test platform.
14. The method of claim 11, wherein the third modulated force is greater than the first modulated force and the second modulated force.
15. The method of claim 11, wherein the pre-impact accelerator is coupled to the test platform via a release mechanism to allow the test platform to decouple from the pre-impact accelerator prior to the catapult accelerator applying the third modulated force to the test platform.
16. The method of claim 11, further comprising adjusting at least one of the first modulated force or the second modulated force in real-time during a test cycle in accordance with a preimpact acceleration profile.
17. The method of claim 12, wherein the test platform is moving in the first direction, is at rest, or is moving in the second direction before the pushing surface contacts the test platform and the catapult accelerator applies the third modulated force to the test platform.
18. The method of claim 11, further comprising, prior to controlling the pre-impact accelerator to apply the first modulated force to the test platform: receiving, based on user input provided via a user interface presented on a user computing device, acceleration profile data indicative of a pre-impact acceleration profile and a collision acceleration profile; and calculating a time series of force parameters, acceleration parameters, velocity parameters, and / or distance parameters for a test cycle, wherein the first modulated force, the second modulated force, and / or the third modulated force are applied to the test platform based on the time series of force parameters, acceleration parameters, velocity parameters, and / or distance parameters.
19. The method of claim 11, wherein the third modulated force is absorbed by a friction damper coupled to the pushing surface or the test platform.
20. The method of claim 11, wherein the pay load comprises one or more vehicle seats fitted with dummies and restraint systems, and wherein the method is performed as part of a vehicle crash test.