M. Da Lio

Supporting Drivers in Keeping Safe Speed and Safe Distance: The SASPENCE Subproject Within the European Framework Programme 6 Integrating Project PReVENT

This paper describes a novel driver-support system that helps to maintain the correct speed and headway (distance) with respect to lane curvature and other vehicles ahead. The system has been developed as part of the Integrating Project PReVENT under the European Framework Programme 6, which is named SAfe SPEed and safe distaNCE (SASPENCE). The application uses a detailed description of the situation ahead of the vehicle. Many sensors [radar, video camera, Global Positioning System (GPS) and accelerometers, digital maps, and vehicle-to-vehicle wireless local area network (WLAN) connections] are used, and state-of-the-art data fusion provides a model of the environment. The system then computes a feasible maneuver and compares it with the drivers behavior to detect possible mistakes. The warning strategies are based on this comparison. The system “talks” to the driver mainly via a haptic pedal or seat belt and “listens” to the driver mainly via the vehicle acceleration. This kind of operation, i.e., the comparison between what the system thinks is possible and what the driver appears to be doing, and the consequent dialog can be regarded as simple implementations of the rider-horse metaphor (H-metaphor). The system has been tested in several situations (driving simulator, hardware in the loop, and real road tests). Objective and subjective data have been collected, revealing good acceptance and effectiveness, particularly in awakening distracted drivers. The system intervenes only when a problem is actually detected in the headway and/or speed (approaching curves or objects) and has been shown to cause prompt reactions and significant speed correction before getting into really dangerous situations.

The LTP experiment on the LISA Pathfinder mission

We report on the development of the LISA Technology Package (LTP) experiment that will fly onboard the LISA Pathfinder mission of the European Space Agency in 2008. We first summarize the science rationale of the experiment aimed at showing the operational feasibility of the so-called transverse–traceless coordinate frame within the accuracy needed for LISA. We then show briefly the basic features of the instrument and we finally discuss its projected sensitivity and the extrapolation of its results to LISA.

A Situation-Adaptive Lane-Keeping Support System: Overview of the SAFELANE Approach

Going beyond standard lane-departure-avoidance systems, this paper addresses the development of a system that is able to deal with a large set of different traffic situations. Its foundation lies on a thoroughly constituted environment detection through which a decision system is built. From the output of the decision module, the driver is warned or corrected through suited actuators that are coupled to control strategies. The input to the system comes from cameras, which are supplemented by active sensors (such as radar and laser scanners) and vehicle dynamic data, digital road maps, and precise vehicle-positioning data. In this paper, the presented system design is divided into three layers: the perception layer, which is responsible for the environment perception, and the decision and action layers, which are responsible for evaluating and executing actions, respectively.

Combining safety margins and user preferences into a driving criterion for optimal control-based computation of reference maneuvers for an ADAS of the next generation

This paper outlines a methodology for combining users preferred driving style and safety margins into an ADASs module for optimal reference maneuver computation. The module for optimal reference maneuver computation is part of the system decision planning chain, which links scenario interpretation to warning intervention strategies. The module objective is the computation of a reference maneuver and produce a measure of the related risk by solving an optimal control problem. In this case, the optimal control problem consists in finding the control functions that minimize the integral of a given penalty function over a planning distance subject to a set of constraints. The penalty function is the mean to implement the safe maneuver concept, which has to comply with three top-level requirements: safety-margins, user acceptance and mobility. In the present work only the safe-speed functionality is addressed and a new penalty function formulation is proposed in order to include both safety criteria and preferred driving style. In this paper it is shown that each users personal driving style can be characterized through a small set of parameters from the analysis of car longitudinal and lateral accelerations that can be easily used in optimal control formulation.

Testing LISA drag-free control with the LISA technology package flight experiment

The LISA test masses must be kept fre eo fs tray acceleration noise to within 3 × 10 −15 ms −2 Hz −1/2 in order to obtain the low-frequency gravitational wave sensitivity goal. The LISA technology package (LTP) is a dedicated ESA flight experiment for testing the drag-free control technology that must ensure purity of free fall in the LISA mission. We present here a brief description of the LTP experimental configuration, specific measurements to be performed and the requirements that must be met in order to demonstrate the LTP stray acceleration upper limit goal of 3 × 10 −14 ms −2 Hz −1/2 at 1 mHz.

Autonomous pallet localization and picking for industrial forklifts: a robust range and look method

A combined double-sensor architecture, laser and camera, and a new algorithm named RLPF are presented as a solution to the problem of identifying and localizing a pallet, the position and angle of which are a priori known with large uncertainty. Solving this task for autonomous robot forklifts is of great value for logistics industry. The state-of-the-art is described to show how our approach overcomes the limitations of using either laser ranging or vision. An extensive experimental campaign and uncertainty analysis are presented. For the docking task, new dynamic nonlinear path planning which takes into account vehicle dynamics is proposed.

Measurement of the momentum transferred between contacting bodies during the LISA test-mass release phase?uncertainty estimation

The requirements for the Laser Interferometer Space Antenna (LISA) test-mass (TM) release phase are analysed in view of the building up of a testing facility aimed at on-Earth qualification of the release mechanism. Accordingly, the release of the TM to free-fall must provide a linear momentum transferred to the TM not exceeding 10−5 kg m s−1. In order to test this requirement, a double pendulum system has been developed. The mock-ups of the TM and the release-dedicated plunger are brought into contact and then the latter is quickly retracted. During and after release, the TM motion is measured by a laser interferometer. The transferred momentum is estimated from the free oscillations following the plunger retraction by means of a Wiener–Kolmogorov optimal filter. This work is aimed at modelling the measurement chain, taking into account procedure, instruments, mechanisms and data elaboration in order to estimate the uncertainty associated with the transferred momentum measurement by means of Monte Carlo simulation.

Measuring random force noise for LISA aboard the LISA pathfinder mission

The LTP (LISA testflight package), to be flown aboard the ESA/NASA LISA pathfinder mission, aims to demonstrate drag-free control for LISA test masses with acceleration noise below 30 fm s−2 Hz−1/2 from 1–30 mHz. This paper describes the LTP measurement of random, position-independent forces acting on the test masses. In addition to putting an overall upper limit for all source of random force noise, LTP will measure the conversion of several key disturbances into acceleration noise and thus allow a more detailed characterization of the drag-free performance to be expected for LISA.

Test‐Mass Release Phase Ground Testing for the LISA Pathfinder Mission

Aim of the LISA Test‐flight Package on board the LISA Pathfinder mission is to provide in‐flight demonstration of some of the LISA critical technologies in achieving the free‐fall condition of a LISA‐like test‐mass in the bandwidth from 1 to 30mHz. Accordingly, owing to high inertial loads arising during the launch phase the test‐mass needs to be firmly secured to the GRS, in order to avoid collision with the surrounding electrodes and housing parts. After the launch and orbit commissioning, the test‐mass must be released to floating conditions, in compliance with strict requirements of initial position and velocity, due to the low force and torque authority made available by the capacitive actuation system. The Caging Mechanism Assembly is being designed by Alcatel Alenia Space Italia and it constitutes the GRS subsystem dedicated to cage and release the test‐mass. The release phase to floating conditions has been identified as critical for the entire mission, therefore a ground‐based verification of suc...

Spacecraft high precision optimized control for free-falling test mass tracking in LISA-Pathfinder mission

LISA (Laser Interferometer Space Antenna) is the first space mission for the in-flight detection of gravitational waves. In order to reduce the mission risk, some of the key technologies needed for LISA is tested by means of the LISA Test-Flight package (LTP) on board the LISA Pathfinder mission (SMART-2). The goal of the LISA Pathfinder is to provide inflight testing of the free-fall level of a reference Test Mass (TM) to within a factor 10 from the LISA top-science requirement. One of the critical technologies to be tested is the Test Masses Drag-Free and Attitude Control System (DFACS), which is the system that has to provide the test masses inertial insulation through satellite relative position control up to the nanometer level. The system analyzed in the paper is modelled as a multibody made of the satellite, actuated through thrusters, and two test masses, kept at a fixed relative distance by using a capacitive actuation. The paper presents a new control design procedure for this MIMO system. The procedure, based on a multi-objective optimization, yields to controllers that achieve the prescribed levels of performance in terms of disturbance rejection, robustness and phase margin.