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Showing papers by "Saab Automobile AB published in 1997"


Journal ArticleDOI
TL;DR: In this paper, the cutting force dynamics in alloyed steel, stainless steel and cast iron have been investigated, although a direct measurement of the cutting forces could not be carried out.

24 citations


Proceedings ArticleDOI
01 Jul 1997
TL;DR: In this article, a feedback-based phase compensation method was proposed to compensate for the phase shift of a rate limiter in a rate limiting control surface, which gave a drastic improvement on stability margins and reduced PIO tendencies.
Abstract: For a modern aerodynamically unstable fighter, like the JAS 39 Gripen, the flight control system typically provides 45° phase margin. Therefore rate limiting control surfaces, which may cause large phase shifts, is an important issue. Software rate limiters are placed on the control servo commands in order to prevent the hydraulic servos from rate limiting. When a rate limiter is saturated, the phase shift drastically reduces the stability margins of the closed loop and increases the risk for pilot-induced oscillation (PIO). This paper describes a novel method for compensating the phase shift of a rate limiter. In contrast to earlier phase compensation methods, this method uses feedback instead of logic or feedforward. Open loop and closed loop properties of the method are discussed. The method gives a drastic improvement on stability margins and reduces PIO tendencies.

22 citations


Patent
16 Sep 1997
TL;DR: In this paper, the authors propose a real-time system for simulating the path of an object in a three-dimensional coordinate system using event-driven protocol using a simulation computer.
Abstract: A device for simulating in real-time a path of an object in a three-dimensional coordinate system. The device includes at least a first unit and a second unit each provided with a GPS receiver for receiving position and timing signals respectively from at least four GPS satellites, a transmitter/receiver for communication between the first unit and the second unit in the VHF or UHF frequencies, and a communication computer having memory capacity and providing a connection between the GPS receiver and the transmitter/receiver. A simulation computer is included at least with the first unit. The simulation computer communicates with the communication computer and simulates with an event driven protocol a path in the coordinate system of the object and communicating the path to the second unit. The communication computer controls the communication through the transmitter/receiver according to an STDMA method.

11 citations


Patent
Patrick Berry1
20 May 1997
TL;DR: In this paper, a wing flap for variable curvature is divided in a plurality of segments (6-9), these segments being arranged to be angularly adjustable in relation to each other, so that the segments together form a curved surface constituting the flap.
Abstract: A wing flap for variable curvature is divided in a plurality of segments (6-9), these segments being arranged to be angularly adjustable in relation to each other, so that the segments together form a curved surface constituting the flap. The angular position of the segments (6-9) in relation to each other and in relation to the very surface of the wing is accomplished by means of an articulating mechanism working in a direction along a vertical cross section of the wing. Said articulating mechanism comprises articulating means which are formed both of link arms (1, 3) and of sliding rods (6a-9a) having variable lengths. Each segment (6-9) of the flap is connected to a sliding rod (6a-9a), the top and bottom shells of the segment being rigidly attached to the top side and bottom side respectively of said sliding rod. Thus the top and bottom shells of the first sliding rod form the first segment in the wing flap, etc. By an arrangement, in which a guide rail (5) makes said link arms (1, 3) to be folded or straightened, the sliding rods (6a-9a) are made to form a polygon curve, the segments (6-9) together with each other then forming a curved flap.

10 citations


Journal ArticleDOI
TL;DR: In this paper, a comprehensive test program was carried out to establish criteria parameters and to generate data to validate the stress and failure analyses of composite laminates containing holes, and good agreement between predicted and measured results was found.
Abstract: Stress and failure analyses of composite laminates containing holes are presented. Both the finite element method (FEM) and an analytical method, based on complex stress functions, are used to determine the stress distributions around the holes. The Point Stress Criterion (PSC) and the Damage Zone Criterion (DZC) are used to predict the tensile strength of test specimens subjected to complex loading conditions. A comprehensive test program was carried out to establish criteria parameters and to generate data to validate the stress and failure analyses. For this purpose a special test fixture was designed. Good agreement between predicted and measured results was found.

10 citations


Patent
Edgren Claes1
18 Dec 1997
TL;DR: In this article, a logic system decides a priority for the displays and delays some non-essential indicators if the vehicle is in a situation which demands attention by the driver, e.g., low washer fluid, if the driver changes torque above a set rate, during braking etc.
Abstract: The vehicle is fitted with a number of sensors to monitor set parameters on the vehicle and power train. A logic system processes the signals and activates displays. The logic system decides a priority for the displays and delays some non essential indicators if the vehicle is in a situation which demands attention by the driver. This is determined by programmed control fields and by grouping the sensors in priority sets. The indication of some parameters eg. low washer fluid, is delayed eg. if the vehicle is being reversed, if the driver changes torque above a set rate, during braking etc. Non essential indicators are activated eg. when the vehicle is being driven at a steady speed along a straight road.

10 citations


Patent
Aronsson Lars1
04 Dec 1997
TL;DR: The floor pan of a road vehicle is composed of a sheet of metal at the front and another sheet at the rear as discussed by the authors, and each of the sills may taper from a given thickness in the front to a very narrow portion just in front of the cutout accommodating each rear wheel.
Abstract: The floor pan (10) is for a road vehicle. It consists of a sheet of metal (11) at the front and another sheet of metal (12) at the rear. There are thickened or raised sills (13,14) on each side of the floor pan. Each of the sills may taper from a given thickness (e) at the front to a very narrow portion just in front of the cutout (15) accommodating each rear wheel. The width (b) of the front flat or profiled part of the floor pan is less than the width (d) of the flat or profiled rear part.

8 citations


Patent
Zimmer Claes1
27 Nov 1997
TL;DR: In this article, a temperature sensor is mounted on a roof bracket of a vehicle to measure the interior temperature of the vehicle for the air conditioning system, and the sensor housing is pref. polypropylene.
Abstract: The temperature sensor (10), to measure the interior temperature of a vehicle for the air conditioning system, is mounted to a roof bracket (24) of the vehicle. The temperature monitor unit (18) projects from the roof bracket (24) into and towards the interior of the vehicle passenger space (25). The monitor (18) has a glass mantle, in a holder of a ceramic material. The sensor housing is pref. of a white plastics and especially polypropylene.

7 citations


Patent
Kvist Lennart1
03 Apr 1997
TL;DR: The spring clamp as mentioned in this paper is a U-shaped main body with a web and two projecting legs, and a spring bracket is formed in one piece with the web and the free end of the bracket is V-shaped.
Abstract: The spring clamp (10) has a U-shaped main body with a web (20) and two projecting legs (22). A circular segment (38) extends outward at an angle from one longitudinal edge of each leg. A spring bracket (40) extends from the centre of a longitudinal edge of the web towards the connection socket on the clamp. Due to its axial dimension, the bracket engages on a flat surface (48) of the outside of the injection line (14) when fitted. The free end of the bracket is V-shaped. The bracket is formed in one piece with the web.

6 citations


Proceedings ArticleDOI
13 Aug 1997
TL;DR: A multispectral imaging MWIR sensor developed by us utilizes the high frame rate made possible by modern FPA arrays and has the capability to perform two point correction in real time, thereby compensating for the different dynamic ranges in each spectral band.
Abstract: There is a trend today towards a reduction in target signatures, the signatures becoming increasingly adapted to the background in which the targets operate. In addition, new types of countermeasures are making the task for optical seekers increasingly difficult. One way to increase the capability of detecting low-signature targets in a countermeasure environment is to utilize not only the magnitude of the signature but also its distribution over the spectrum. For collection of information regarding the spectral signatures of targets, countermeasures and backgrounds, a multispectral imaging MWIR sensor has been developed by us. This device utilizes the high frame rate made possible by modern FPA arrays. Such an array has been combined with a rapidly rotating filter wheel, thereby producing images of 128 by 128 pixels in six wavelength bands in the 2 - 5 micrometer region at a frame rate exceeding 30 Hz in each band. The sensor has a field-of-view of 3.7 degrees and a pixel resolution of 0.5 mrad. The sensor has the capability to perform two point correction in real time, thereby compensating for the different dynamic ranges in each spectral band. An extensive measurement program is in progress for gathering data for targets, countermeasures and backgrounds. Selected results from this program are presented.

5 citations


Patent
11 Dec 1997
TL;DR: In this paper, the guide is arranged so that when the backrest is folded, it takes the belt away to the adjacent bodywork wall, leaving the front seat free of the belt.
Abstract: The guide (6) is arranged so that when the backrest is folded, it takes the belt away to the adjacent bodywork wall, leaving the backrest free of the belt. The guide has an upper arm (7) pivoted to the bodywork. The belt is controlled by this arm. With the backrest folded up, the upper arm is held in its initial position projecting over the backrest. When the backrest is folded down, it is automatically turned towards the side, holding the belt, so that the backrest is left free of the belt when it is folded in either direction.

Book ChapterDOI
01 Jan 1997
TL;DR: The main conclusions concerning the use of μ-synthesis are: Handling qualities requirements as formulated in the HIRM problem can easily be incorporated in the design and robustness to modelling errors can be handled in a straightforward way.
Abstract: It is described how the μ-synthesis method was used to design a controller for the HIRM benchmark problem. Controllers for the longitudinal and lateral axes were designed. For the longitudinal axis a fixed-gain controller was designed, but for the lateral axis designs were carried out for a low and a high angle of attack flight case. The main conclusions concerning the use of μ-synthesis are: Handling qualities requirements as formulated in the HIRM problem can easily be incorporated in the design. Robustness to modelling errors can be handled in a straightforward way whereas robustness due to variations in flight case can be more difficult to include. It may be a bit difficult to choose weighting transfer functions that reflect the requirements in an appropriate way, and quite some time is spent on tuning the weighting transfer functions.


Patent
14 May 1997
TL;DR: In this article, a method and a device for purifying methane gas in a Raman cell is described. But the method is not suitable for the use of large amounts of methane, as it can react with each other and as time passes form organic compounds, which are deposited on the inner side of the windows.
Abstract: The present invention relates to a method and a device for purifying methane gas in a Raman cell (20). When pumped laser light having a high power passes through the Raman cell containing methane gas, a portion of the methane can be decomposed, and then highly reactive methyl radicals are formed. They can react with each other and as time passes form organic compounds, which are deposited on the inner side of the windows (22a, 22b) of the Raman cell. A trap (26) comprising calcium grains (27), which absorb the methyl radicals, is introduced in the Raman cell (20). The methane gas, which comprises a small content of methyl radicals, is made to come in contact with the calcium grains (27), whereby a reaction occurs between the methyl radicals and the calcium grains, so that calcium carbide and calcium hydride are formed. The methane gas is driven around in the Raman cell (20) and through the trap (26) by means of a compressor wheel (28) driven by a motor (29c).

Book ChapterDOI
01 Jan 1997
TL;DR: An algorithm has been described for preprocessing the grid to achieve a good static-load balance on the processors in parallel computation for compressible Navier–Stokes equations.
Abstract: Publisher Summary Many floating-point operations and many grid points are required for an accurate approximation of the steady state solution of compressible flow problems in aerospace applications. The compressible Navier–Stokes equations model the flow of air around airplanes very well. In the parallel implementation, a processor is dedicated to one or several blocks of the grid. The difference stencil at a block boundary needs solution data from the neighboring block on the other side of the boundary. For calculations around realistic aircraft configurations, the number of blocks generated by a grid generator is often greater than the number of available processors. If the processor speed differs in the network, then their relative performance is estimated by submitting a small test program to all the slave processors. The computation automatically recovers after the failure of a slave processor, but when the master processor fails, the computation must be restarted manually or by the queuing system if this is used. An algorithm has been described for preprocessing the grid to achieve a good static-load balance on the processors in parallel computation.

Patent
16 Sep 1997
TL;DR: In this article, a real-time simulator for simulating the position of a possibly fictitious object in a three-dimensional coordinate system is described, comprising at least a first unit and a second unit.
Abstract: A device is described for simulating in real time the position of a possibly fictitious object in a three-dimensional coordinate system, comprising at least a first unit and a second unit. Each unit is provided with a GPS-receiver (2) for receiving position and timing signals respectively from at least four satellites, furthermore with a transmitter/receiver for communication between the first and second units and a communication computer (6) having memory capacity and connecting the GPS-receiver (2) and transmitter/receiver (4). The device is in particular characterized in that at least the first unit contains a simulation computer (7) communicating with the communication computer and simulating the position in the coordinate system and in time of said object and communicating this information to the second unit and the that the communication computer (6) is arranged to control the communication through the transmitter/receiver (4) according to the STDMA-method.

Patent
Arulf Oerjan1
04 Mar 1997
TL;DR: In this paper, a rotational movement system for a satellite during discharge from an adapter of a launch vehicle was proposed, which includes at least one line dismountably attached to a first point on the satellite and a first points on the adapter.
Abstract: A device for imparting rotational movement to a satellite during discharge from an adapter of a launcher. The satellite includes a first axis, a second axis, and a third axis passing through a center of gravity. The first axis, the second axis, and the third axis are mutually perpendicular. The device includes at least one line dismountably attached to a first point on the satellite and a first point on the adapter. The at least one line is attached to the satellite and the adapter such that the at least one line imparts a rotational movement to the satellite as the satellite is discharged and separates from the adapter with a discharge velocity in a direction along the first axis. A lock dismountably attaches the at least one line to the satellite.

Patent
Arulf Oerjan1
12 Sep 1997
TL;DR: In this paper, the first and second points of the line component on the satellite were located relatively close to one another, and the line components with their other ends fixed at points on the adaptor were shown to be mechanical with a locking spring holding a component fixed to the end of a line component.
Abstract: The second axis (6,7) of the satellite (3) forms an angle with the satellite speed vector, ie its first axis (5) At least one line component (8,9) is releasably locked in a first point (10,11) on the satellite and is fixed at a second point (13) on the adaptor The first and second points are so located relatively to one another that the line component on separation of the satellite from the adaptor exerts a turning torque on the satellite The lock component is clearly mechanical with a locking spring holding a component fixed to the end of the line component The line components with its other ends are fixed at points on the adaptor On separation of the satellite from the adaptor by separation springs a relative speed occurs between the satellite and the support rocket, with the line component being stretched until the lock component releases it