F. Lenzi

Decreased density of the platelet serotonin transporter in pathological gamblers.

Background/Aims: The aim of this study was to investigate the serotonin transporter (SERT), by means of the 3H-paroxetine ([3H]-Par) binding to platelet membranes, in patients affected by pathological gambling (PG), as compared with a similar group of healthy control subjects. Methods: Seventeen PG patients were selected amongst those who were drug-free and at the first psychiatric interview in a Department of Addiction. The diagnosis was assessed according to DSM-IV criteria and PG severity was measured by means of the South Oaks Gambling Screen. The platelet [3H]-Par binding was carried out according to a standardized method. The binding parameters, the maximum binding capacity (Bmax) and the dissociation constant (Kd), were obtained by means of the Scatchard analysis. Results: The Bmax values of PG patients were significantly lower than that of healthy subjects, while the Kd values were not different in the two groups. No significant effect of age, sex or psychiatric comorbidity on Bmax or Kd was observed; there were also no correlations between clinical and biological variables. Conclusions: PG patients showed a dysfunction at the level of the platelet SERT that would suggest the involvement of the 5-HT system in this condition.

Electronic Control of a Motorcycle Suspension for Preload Self-Adjustment

This paper describes the application of electronics to the control of the rear suspension of a motorcycle. The aim of the system is to make the suspension work around its optimal operating point, so that the safety and comfort of the vehicle can be improved. In fact, variations of the load carried by the vehicle determine a change of the suspension spring compression that moves the operating point away from the optimal value. Spring compression can also be changed by varying the suspension preload. The electronic system described here reveals load changes and automatically adjusts the motorcycle suspension preload in order to compensate the load variation and keep the suspension to its optimal operating point. The system is based on a linear position sensor that monitors the actual stroke of the suspension and a microcontroller that executes the control algorithm and drives the preload actuator. Road tests carried out on a motor scooter equipped with the system show its correct functionality and demonstrate the achievement of a better operation of the suspension with simple hardware and cost affordable for the two-wheel market.

Distributed sensor for steering wheel grip force measurement in driver fatigue detection

This paper presents a low-cost and simple distributed force sensor that is particularly suitable for measuring grip force and hand position on a steering wheel. The sensor can be used in automotive active safety systems that aim at detecting drivers fatigue, which is a major issue to prevent road accidents. The key point of our approach is to design a chain of sensor units, each of them provided with some intelligence and general purpose capabilities, so that it can serve as platform for integrating different kinds of sensors into the steering wheel. A proof-of-concept demonstration of the distributed sensor consisting of 16 units based on capacitive sensing elements has been realised and preliminary results are presented.

Voice coil actuators: From model and simulation to automotive application

This paper describes an innovative linear voice-coil-actuated automatic sequential gear with manual shift for a Formula Student race car. The application is novel to linear voice coil actuators, which are usually adopted in PC hard disks or speakers. A model, which comprises both the dynamic and thermal characteristics of the adopted voice coil is developed to perform several co-simulations of the electrical and mechanical parts of the system. Model validation is also presented. The experiments show that voice coil actuators offer an alternative solution to pneumatic and hydroelectric systems in this application, avoiding the need of any extra-circuit (e.g. for air or oil), compressor or tank.

Embedded electronic control system for continuous self-tuning of motorcycle suspension preload

Comfort and safety of vehicles significantly depends on the behavior of the suspension system. This is particularly true in two-wheel vehicles where the equilibrium is fundamental. Variations of the static load on the vehicle determine a compression of the suspension spring that modifies the static equilibrium point with respect to the optimal value. The system we describe is capable of continuously correcting the suspension preload of a motorcycle without user intervention, in order to compensate the load variations. The electronic system is based on a microcontroller and a linear position sensor that measures the suspension stroke. It executes a closed-loop control algorithm that adjusts the preload and maintains the average value of the suspension stroke constant. The experimental results coming from road tests performed on a scooter are reported and discussed.

A Hardware-Software Platform for Design and Verification of In-Motorcycle Electronic Systems

This paper describes a hardware-software platform suitable for rapid prototyping of electronic systems for in-motorcycle applications. The hardware platform architecture is characterized by two programmable components consisting of an 8-bit microcontroller and a PC-like device, such as a portable PC or a PDA, which communicate by means of a Bluetooth wireless link or a CAN bus. The application can dynamically be partitioned on the two processors, during the design and verification phases. This allows the hardware-in- the-loop simulation and the fine-tuning of the control algorithm before porting the application to the embedded processor. Two application examples for motorcycles are presented. They demonstrate that the designed hardware/software platform leads to rapid and low-cost implementations of innovative in- motorcycle electronic systems.

Sensorless control of the suspension preload in motorcycles

This paper describes the sensorless control of a motorcycle suspension preload. The aim of the system is to make the suspension work around its optimal operating point, making the vehicle height independent of the load carried. This improves the safety and comfort of the vehicle. The electronic system described here reveals load changes and automatically adjusts the motorcycle suspension preload in order to compensate the load variation, without expensive sensors. The preload is set by means of a DC motor and a worm gear that in its turn regulates the preload hydraulic piston. The basic idea is to monitor the DC motor current during activations and calculate the load torque, which carries information on the actual vehicle load. This allows the feedback chain to be sensorless. Laboratory experiments carried out on a benchmark demonstrate that the system is able to guarantee the same correct functionalities as the sensored prototype, but with a great cost saving.

Using a very low-cost hall sensor for motorcycle indicator automatic turn-off: an experimental study

Motorcycles are becoming the preferred means of transportation for many people in crowded and mild climate cities. Nevertheless, they still offer a rather low level of safety, as compared to cars, in which the use of electronic systems has led to effective improvements of the vehicle safety. The purpose of this paper is to show the feasibility of a very low-cost approach to the implementation of a control system that switches the motorcycle indicators off automatically. The electronic system is based on a low-cost industrial Hall sensor that is used to recognize when a turn is completed by reading the Earthpsilas magnetic field. The system electronics is simple and thus affordable for the motorcycle industry. Preliminary experimental results are shown and discussed to demonstrate the feasibility of the solution that may lead to a significant improvement of the safety of two-wheeled vehicles.