Patent Application
20080268404
I. Field
The following description relates generally to systems and methods for training pilots.
II. Background
Historically, the art of flying a helicopter has been learned by some amount of academic education combined with a massive amount of practical training and experience.
Often, training starts in some form of conventional simulator where a pilot sits in a safe environment where the pilot interacts with a set of imitation helicopter controls. As the pilot interacts with the controls, a set of sensors coupled to the controls will monitor the forces applied by the pilot. In turn, a complex set of control programs will use the output of the various sensors to approximate those changes of states that a normal helicopter would experience. In response to the control programs, a set of hydraulic actuators will move the bulk of the simulator to simulate the actual motion a pilot would normally feel.
Unfortunately, such simulated environments do not provide the robust experience needed for many situations a pilot may encounter. On the other hand, the actual experience of such situations can be so hazardous for an inexperienced pilot that many helicopter crews may be injured or lost and/or their aircraft damaged or destroyed.
Accordingly, new technologies directed to improving pilot training are may be useful.
Various aspects and embodiments of the invention are described in further detail below.
In an embodiment, a training apparatus includes a moveable platform configured to allow an operating aircraft to land upon it, a set of actuators mechanically coupled to the platform to cause the platform to be controllable moved in a plurality of degrees of freedom, and control circuitry coupled to the set of actuators, the control circuitry configured to cause the moveable platform to move according to a simulated environment.
In another embodiment, a training apparatus includes a moveable platform configured to allow an operating aircraft to land upon it, a first means coupled to the platform for causing the platform to be controllable moved in a plurality of degrees of freedom, and a control means coupled to the set of actuators, the control means for causing the moveable platform to move according to a simulated environment.
The features and nature of the present disclosure will become more apparent from the detailed description set forth below when taken in conjunction with the accompanying drawings in which reference characters identify corresponding items.
The disclosed methods and systems below may be described generally, as well as in terms of specific examples and/or specific embodiments. For instances where references are made to detailed examples and/or embodiments, it should be appreciated that any of the underlying principals described are not to be limited to a single embodiment, but may be expanded for use with any of the other methods and systems described herein as will be understood by one of ordinary skill in the art unless otherwise stated specifically.
Piloting of any sort is an inherently dangerous occupation, and it may be impossible to remove all risk for even the most mundane of environments. However, there are certain situations that are considered notoriously dangerous even for the most experienced of pilots.
Among such situations are helicopter deck (“helideck”) landings at sea where a helicopter pilot may be required to land his aircraft on a relatively small platform at the back of a ship that may be tossing and turning in response to rough seas.
While such situations may be simulated in conventional simulators, such simulations have limited usefulness. Further, “on-the-job” experience can be so hazardous that lives are lost and aircraft destroyed every year as even the most experienced of pilots may have limited experience with different seagoing conditions.
In response to this situation, the following methods and systems were developed to enable a new form of training where a pilot, flying the helicopter of choice, can practice landings and takeoffs using a platform controlled in a way that simulates the motion of a helideck platform in any number of seagoing conditions.
Additionally, in various embodiments in may be useful to include yet another degree of freedom to take advantage of any wind that may be present. That is, in certain seaside locations, such as Newfoundland, Canada, wind can be guaranteed practically any day, but of course the direction of that wind will vary from day to day, hour to hour. Thus, it may be useful to enable the simulated helideck platform 112 to rotate about a central axis and normal to the horizontal plane of the base of the simulated helideck platform 112. By adding such a feature, pilots can practice takeoffs and landings while effectively controlling wind direction for the greatest diversity of training exercises.
In various embodiments, helideck rotation can take place about a full 360 degrees. However, in various embodiments it may be technically easier, yet still effective, to enable rotation about lesser angles, e.g., 270 degrees, 180 degrees or 90 degrees.
Note that, given that the helideck simulation system is located outdoors and used in concert with actual helicopters, it may be beneficial to use actuators far stronger than used in ordinary simulators and having some extra form of corrosion resistance, such as a ceramic coating or other corrosion-resistant materials.
In operation, the platform 210 may be made to move about 1-6 degrees of freedom by virtue of the hydraulic actuators 220, which are themselves controlled using hydraulic control systems (not shown) and some form of computer circuitry (also not shown).
While it is certainly possible to perform rotation about the circular base rails/drives 230 at any time, in various embodiments rotation may be limited to times when the hydraulic actuators 220 are not moving and/or set to secure/settled positions. The turntable can then be locked firmly before the actuators are allowed to move (reproducing ship motions). Generally, (but not necessarily) rotation may be accomplished using a skidding system or by using a number of electric or hydraulic motors, and rotation accuracy may be feasible to within +/−1° or less.
For calculations of the motion system it is important to choose one principle (top or bottom rotation) in an early development stage since this choice affects the forces on the actuators 220, i.e., the weight supported by the actuators in second helideck embodiment 112-B may be substantially greater. For example, according to one set of calculations for specific embodiments, the minimum static force against the actuators for the first helideck embodiment 112-A may be about 89,000 lbs while the minimum static force against the actuators for the second helideck embodiment 112-B may be about 99,000-102,000 lbs.
Continuing, some consideration of the simultaneous and non-simultaneous velocities and accelerations of a landing platform may be taken into account in order to fully reproduce realistic helideck movements. The derived velocities and accelerations are not included in this document, but are fully within the capacity of one of ordinary skill in the art to derive.
Various issues to be considered include: (1) the length of the cushioning zone of the actuators, (2) the available hydraulic Power, (3) the size of hydraulic components (valves, piping, hoses, etc.), and (4) simultaneous heave and pitch velocities.
For various ocean/water wave frequencies (T=5 . . . 15s), the heave-velocity versus pitch-velocity coupling of a helideck platform is calculated and plotted in 4. In view of
Next, with regard to simultaneous roll and sway velocities, attention is drawn to
For non-simultaneous motions the following is assumed: The non-simultaneous velocities and accelerations in rotational directions are based on a reference wave with a wave period of approximately 5 seconds. It is also assumed that this wave pattern results in a movement of maximum single rotational degree of freedom excursions. The linear velocities are selected at 2.0 m/s, and overall non-simultaneous velocities may be found in Table 1 below:
Continuing,
Table 2 is an exemplary set of actuator velocities for a system using six actuators. Actuator velocities are calculated for simultaneous and non-simultaneous motions.
Table 2 shows that the largest actuator velocity (2.251 m/s) appears during the non-simultaneous roll or simultaneous motion.
Continuing, the following is a discussion of simultaneous and non-simultaneous acceleration requirements of a exemplary motion base. The simultaneous and non-simultaneous acceleration requirements will mainly be used (in further analyses) to determine the nominal actuator force and nominal forces on floor pads/joints.
Also the worst case accelerations due to a failure in controls (Valve zero, or cushioning) are described. The worst case accelerations will be mainly be used to determine the worst case forces on floor pads and joints.
For various wave frequencies (T=5 . . . 15s), exemplary heave-velocity versus pitch-velocity coupling is calculated and plotted in
The wide and long ellipses represent the high frequent motions. The lower frequent motions are represented by the small and shorter ellipses. Maximum simultaneous acceleration requirement of the present embodiment is approximately 4 m/s2 heave together with 2°/s2 pitch.
Continuing, roll acceleration depends on the roll frequency and amplitude. It is assumed in the present embodiment that the period time of the roll shall not be lower than 5 seconds and that the roll amplitude shall not exceed 15°. In
For the non-simultaneous motions the following is assumed: The nominal non-simultaneous velocities and accelerations in rotational directions are based on a reference wave with a wave period of approx. 5 seconds. It can be further assumed that this wave pattern results in a movement of maximum single rotational degree of freedom excursions. This will result in an acceleration of 0.25 g. Considering wave patterns, which may exist in a broad spectrum, higher wave periods can occur. Therefore the linear accelerations are selected at 0.5 g.
Continuing, in
Table 4, exemplary accelerations of the six actuators are calculated for simultaneous and non-simultaneous motions.
Table 4 shows that the largest actuator acceleration (±3.99 m/s2) appears during the non-simultaneous heave motion.
Worst case accelerations of a platform may occur due to failure(s) in one or more of the actuators. During a failure the actuator can generate higher forces than that the motion base requires nominally, which results in significant higher acceleration than the nominal accelerations:
In general, two types of extreme forces can cause extreme accelerations of the payload including:
Worst case forces: This is the maximum force that can occur during a failure (cushioning, valve null etc.). Reaction forces of the six upper pads are calculated when one actuator loads its upper pad with the maximum force, while the other five actuators are locked (no acceleration, no velocity). All possible system positions (64 combinations of extended and retracted actuators) are investigated to find the extreme resulting forces on the upper pads. The results are shown in
Table 5. These results do not include a safety factor. In retracted position the actuator loads the upper pad with 1967 kN pushing. Totally extended, the actuator loads the upper pad with 1441 kN pulling. Two cases are considered, including when a helicopter is at an extreme position on deck and when the helideck is empty
Maximum Nominal Force: These values are theoretical values that are calculated using the maximum nominal force that the actuators can generate. During normal simulation (normal mode), these values are limited by software. During operation in manual mode, certain test signals (for instance step response) may generate these accelerations. These values do not include the normal gravity acceleration. In neutral the system is optimal compensated, i.e., not static force. The nominal cylinder force (pressure times surface)=0.0346*180 bar=623 kN.
The extreme accelerations the specified loading conditions are summarized in
Table 5. The last column shows the maximum extreme accelerations of the column 2 to 4. The accelerations in the last column are design parameters for the helideck (payload).
Continuing, the minimum required non-simultaneous velocities/accelerations of the exemplary platform are summarized below:
Simultaneous velocities/accelerations can be summarized by:
Worst case accelerations may occur due to failure(s) in one or more of the actuators. During such failure, the actuator can generate higher forces than that the motion base requires nominally, which results in significant higher accelerations of the MRP than the nominal required accelerations.
In operation, the control system 810 can be first activate and an appropriate control input selected, such as any of the set of manual controls 830, the sine-wave generator 812 and a set of history/telemetry records 814.
Next, assuming rotation of the relevant helideck platform is made or unnecessary, the hydraulic controls 820 and actuators 220 moving the helideck platform 210 may be activated and used as necessary or desired.
In step 904, the helideck platform may be rotated to a desired angle, and optionally locked down afterward. Next, in step 906, the hydraulic controls and actuators moving the helideck platform may be activated. Control continues to step 908.
In step 908, a set of training exercises may be performed with the helideck platform moved by the actuators under control of the control circuitry and control input, and in step 910, training may be monitored as desired. Generally, training may include repeatedly landing and taking off based upon at least one set of simulated seagoing conditions and perhaps a variety of simulated conditions. Control then continues to step 950 where the process stops.
What has been described above includes examples of one or more embodiments. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the aforementioned embodiments, but one of ordinary skill in the art may recognize that many further combinations and permutations of various embodiments are possible. Accordingly, the described embodiments are intended to embrace all such alterations, modifications and variations that fall within the spirit and scope of the appended claims. Furthermore, to the extent that the term “includes” is used in either the detailed description or the claims, such term is intended to be inclusive in a manner similar to the term “comprising” as “comprising” is interpreted when employed as a transitional word in a claim.
This Application claims priority to U.S. Provisional Patent Application No. 60/847,364 to Mr. Rick Burt filed on Sep. 27, 2006 entitled “Novel Training Platform and Related Method of Operation”. The contents of the above-reference Provisional Application are incorporated by reference in their entirety for all purposes.
| Number | Date | Country | |
|---|---|---|---|
| 60847364 | Sep 2006 | US |
