Experimental test of vehicle longitudinal velocity and road frictim estimation for ABS system

Antilock Braking System (ABS) is designed to prevent wheels from locking, in order to enhance vehicle directional stability during braking manoeuvres. Basically, ABS closed-loop control logic uses tyres slip as control variable. Slip is estimated by comparing vehicle reference speed with the angular speed of each wheel. Thus it is crucial to correctly estimate the longitudinal vehicle speed, in order to get a control system capable of good performance. The control is also affected by road condition; since vehicles are not equipped with sensors able to measure the tyre/road friction coefficient, an other estimation has to be performed. The paper presents an algorithm for the estimation of longitudinal speed, based on the measurements of the four wheel angular speed. A method to assess the road friction, commonly known as "learning phase" is also described: it is carried out during the early stage of the active control intervention and relies on the wheel rotation sensors as well. At first the algorithms are tested through simulation, using a validated 14 degrees of freedom vehicle model. The hydraulic components of the ABS control unit are characterized through experimental tests and then modelled using transfer functions in order to correctly simulate the brake circuit pressure gradient during braking manoeuvres. The influence of different logic updating frequencies over the estimation error is investigated, as well as the sensitivity to several control parameters. The algorithms are then tested through a Hardware in the Loop (HiL) test bench in order to verify their compatibility with real time working conditions. Estimation outputs are compared with analogous values calculated by a commercial control logic. Copyright © 2009 SAE International

Excellent outcome in patients with primary biliary cholangitis in Northwest Italy followed up for up to 30 years

Objective Primary biliary cholangitis (PBC) is a rare chronic autoimmune cholangiopathy, characterized by a variable course and response to treatment. We aimed to describe long-term outcomes of PBC patients referred to three academic centres in Northwest Italy. Methods This is an ambispective cohort study of PBC patients (retrospective component: diagnosis before 1 January 2019; prospective component: thereafter), including 302 patients: 101 (33%) followed up in Novara, 86 (28%) in Turin, 115 (38%) in Genoa. Clinical features at diagnosis, biochemical response to therapy and survival were analyzed. Results Among the 302 patients (88% women, median age 55 years, median follow-up 75 months), alkaline phosphatase (ALP) levels significantly decreased during treatment with ursodeoxycholic acid (UDCA, P < 0.0001) and obeticholic acid (P < 0.0001). At multivariate analysis, ALP at diagnosis was predictive of 1-year biochemical response to UDCA [odds ratio 3.57, 95% confidence interval (CI) 1.4-9, P < 0.001]. Estimated median survival free of liver transplantation and hepatic complications was 30 years (95% CI 19-41). Bilirubin level at diagnosis was the only independent risk factor for the combined outcome of death, transplantation or hepatic decompensation (hazard ratio, 1.65, 95% CI 1.66-2.56, P = 0.02). Patients presenting with total bilirubin at diagnosis ≥0.6 times the upper normal limit (ULN) had a significantly lower 10-year survival compared to those with bilirubin <0.6 times ULN (63% vs. 97%, P < 0.0001). Conclusion In PBC, both short-term response to UDCA and long-term survival can be predicted by simple conventional biomarkers of disease severity, obtained at diagnosis

Numerical analysis of the influence of an actively controlled spoiler on the handling of a sports car

Normal force distribution among tires significantly affects the performance of the vehicle, especially in terms of handling and safety. Consequently, evolving technologies for controlling and regulating normal loads have the potential of boosting the controllability of the vehicle. This paper illustrates the effectiveness of the actively controlled aerodynamic system to increase the performance and the safety margins of a sports car in cornering maneuvers; normal loads on the front and rear axles at high speed are controlled by changing the angle of attack of the front and rear spoilers in opposite directions to alter load distribution. The performance of the controlled system is analyzed through a nonlinear 14-degree-of-freedom vehicle model. Numerical simulations are carried out to understand how the control logic can affect oversteer/understeer response, improving both stability and performance of the vehicle. Robustness of the control systems toward the variation of friction coefficient is also assessed

The costs of multiple sclerosis: A cross-sectional, multicenter cost-of-illness study in Italy

Objectives: To estimate the socio-economic impact of multiple sclerosis (MS) in Italy. Methods: Outpatients with MS were enrolled at 44 centres across Italy. Socio-demographic, clinical and resource utilization data were collected using a validated questionnaire. Each patient completed a weekly diary of expenses due to MS over a three-month period. Direct health care costs and indirect costs (lack of productivity for the patient and for caregivers) were assessed for the whole population and were compared among five groups, categorised by disease severity (EDSS score). An analysis of variance was carried out on socio-demographic variables. Results: For the total population of 566 patients, the mean direct cost over three months was ITL 2,134,000, the mean indirect cost was ITL 7,775,000. Costs were significantly higher for male patients (p < 0.05) and showed a significant increase with increasing age (p < 0.0005), disease duration (p < 0.0005) and disease severity (p < 0.0005). Costs for patients in a progressive phase were significantly higher (p < 0.0005). There were no significant geographical differences among the regions of Italy. Conclusions: This study confirms that MS represents a high economic burden, with indirect costs greatly exceeding direct costs. Unpaid caregivers remain the culturally accepted mode of care for MS patients in Italy and this study illustrates the impact of their loss of earnings. As costs increase with disease progression, these findings suggest that treatment efforts should focus on patients in the early stages of MS, in order to slow down disease progression