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The design of suspension systems for heavy-duty vehicles covers a specific field of automotive industry. The proposed work focuses on the design development of a front controllable suspension for an agricultural tractor capable to satisfy the system requirements under different operating conditions. The design of the control algorithms is based on the developed multibody model of the actual tractor, including the pitch motion of the sprung mass, the anti-dive effects during braking and forward-reverse maneuvers and the non-linear dynamics of the actuation system. For an advanced analysis, a novel thermo-hydraulic model of the hydraulic system has been implemented. Several semi-active damping controls are analyzed for the specific case study.

This paper presents an analysis of time-optimal maneuvers of a race motorcycle in the circuit of Adria (Italy) with different choices of gearbox ratios. The minimum lap time is found by means of the Optimal Maneuver Method, whose theoretical basis is presented in [1], [3], [4], [10]. The method essentially solves a two-point boundary value optimal control problem by finding the driver's inputs that minimize an objective function (i.e. the minimum-lap time). The good agreement between the method results and data acquired by a measurement system mounted on board a motorcycle driven by expert drivers justifies its use as a tool for vehicle set up and design parameters analysis. In the past the method was extensively used to analyze the influence, on racing vehicle performance, of geometry, mass properties distribution, tire and engine power characteristics as shown in papers [2], [6], [7].

The constantly growing engine power of modern racing motorcycles makes it possible to increase their performance, i.e. to reduce the lap time. The aim of this work is to investigate the relationships between the motorcycle characteristics and its performance by means of the optimal manoeuvre method. This is a powerful technique that essentially, simulates a perfect driver and calculates the minimum lap time for a given motorcycle in a given circuit. Several simulations were carried out on a test circuit, which includes a part of the real Mugello racetrack. Results show that as the engine power increases the lap time decreases and it tends to a limit value. Moreover, for a given engine power, one can find a particular position of the center of mass that leads to the best performance; performances can be improved by adjusting the wheelbase too. Furthermore, best performance can be only reached if the rider chooses the right trajectory for any different vehicle.

This paper deals with the application of the optimal maneuver method to the assessment of motorcycle maneuverability. The optimal maneuver method is a novel approach to the analysis of vehicle performance. The essence of this method is the solution of an optimal control problem which consists in moving the vehicle, according to holding trajectory constraints, between two given endpoints in the “most efficient way”. The concept of “most efficient” is defined by a proper penalty function defined to express maneuverability. In this paper we briefly outline the method and give examples of its application to three classical maneuvers commonly used to test motorcycle handling: a slalom test, a lane change maneuver and a U-curve.