Exfo Inc.

Volvo Car Corporation

Mats Skold

Mathias Westlund

Henrik Sunnerud

Tony Gustafsson

Peter Andrekson

Mats Jonasson

Gang He

Bernard Ruchet

Daniel Gariepy

A method is described for determining a friction estimate between a road surface and a tire of a vehicle, the tire being arranged on a steerable wheel of the vehicle, and the vehicle having an axle rack pivotably attached to a linkage arm connected to the steerable wheel such that a translational motion of the axle rack causes the linkage arm to rotate about a kingpin element such that the linkage arm causes a turning motion of the steerable wheel. The method includes acquiring a plurality of rack force values; acquiring a plurality of lateral wheel force values; mapping a relation between the plurality of rack force values and the lateral wheel force values to a model; and determining the lateral friction estimate based on the mapping.

Method and system for computing a road friction estimate

A method is described for computing a friction estimate between a road surface and a tire of a vehicle when the vehicle is in motion along a course, the tire being arranged on a steerable wheel of the vehicle, and the vehicle including two front wheels and two rear wheels and an axle rack pivotably attached to a linkage arm connected to the steerable wheel such that a translational motion of the axle rack causes the linkage arm to rotate about a kingpin element such that the linkage arm causes a turning motion of the steerable wheel. A corresponding system and vehicle are also described.

A method in a vehicle for determining road properties is described. The method includes: acquiring vehicle acceleration in x, y and z directions; acquiring a rack force; acquiring a wheel speed for each of all four wheels; determining a wheel speed energy based on the wheel speed; determining a wheel slip of all four wheels of the vehicle based on a respective wheel speed of the wheel; determining an acceleration energy in each of the x, y and z-directions based on the vehicle acceleration and the vehicle speed; determining a rack force energy based on the detected rack force; and determining road properties based on the wheel speed energy, rack force energy and vehicle speed. A system is also described for performing the method.

Method and system for determining road properties in a vehicle

There is provided a system and a method for determining an in-band noise parameter representative of the optical noise contribution (such as OSNR) on a polarization-multiplexed optical Signal-Under-Test (SUT) comprising two polarized phase-modulated data-carrying contributions and an optical noise contribution. For each of a multiplicity of distinct polarization-analyzer conditions, the SUT is analyzed to provide at least one polarization-analyzed component of the SUT and the polarization-analyzed component is detected with an electronic bandwidth at least ten times smaller than the symbol rate of the SUT to obtain a corresponding acquired electrical signal; for each acquired electrical signal, a value of a statistical parameter is determined from the ac component of the acquired electrical signal, thereby providing a set of statistical-parameter values corresponding to the multiplicity of distinct polarization-analyzer conditions; and, from the set of statistical-parameter values, the in-band noise parameter is mathematically determined.

In-band OSNR measurement on polarization-multiplexed signals

There is provided a method and an apparatus for determining quality parameters on a polarization-multiplexed optical signal based on an analysis of the power spectral density of the Signal-Under-Test (SUT). The method is predicated upon knowledge of the spectral shape of the signal in the absence of significant noise or spectral deformation. This knowledge is provided by a reference optical spectrum trace. Based on this knowledge and under the assumption that ASE noise level is approximately constant in wavelength over a given spectral range, the spectral deformation of the signal contribution of the SUT may be estimated using a comparison of the spectral variations of the optical spectrum trace of the SUT with that of the reference optical spectrum trace.

Signal deformation measurement on polarization-multiplexed signals

A two-gate sampling system has been designed to perform sampled balanced detection of one or more input signal pairs. The present invention performs simultaneous sampling of both signals in each signal pair followed by digitization and combination of the sample pairs using software. By first sampling the signals and then combining the sampled into the corresponding balanced detected signal it is possible to avoid the bandwidth limitations and impedance problems introduced by traditional balanced detectors and electrical oscilloscopes. In particular, for optical sampling gates very high bandwidth sampling gates can be designed without any impedance issues and hence almost perfect balanced detection reconstruction can be performed for very high speed signals. Balanced detection is becoming more and more important as the new phase modulated optical data signals are introduced to the market, such as e.g. PSK, DPSK, QPSK and DQPSK. The present invention is well suited for analysis of these new types of signals.

Sampling-based balanced detection system

An optical sampling arrangement for high-speed measurement of the time-varying electric field of an optical input signal utilizes coherent mixing of the optical input signal with a reference laser source in a phase-diverse optical hybrid solution, followed by optical sampling of the coherently-mixed fields at the output of the optical hybrid. The generated streams of optical samples are then detected and signal processed in order to reconstruct a sampled version of the electric field of the original optical input signal.

Growing community of inventors

Gothenburg, Sweden

Mats Skold