Fabio Todeschini

A full hybrid electric bike: How to increase human efficiency

Energy and environmental considerations, new paradigms for urban mobility and transportation increased in the past few years the interest on Light Electric Vehicle (LEV). In that context, Electrically Power Assisted Cycles (EPACs) received a great attention: several efforts have been made in order to improve their performance in terms of autonomy, weight, esthetic and feeling with the driver. In this work, project and realization of a full hybrid electric bike (HEB) are presented. The main idea, borrowed from the more explored 4-wheel world, is to use the possible energy fluxes between cyclist and motor in order to improve the efficiency of the primary engine (the human body) being completely self-sustaining and grid-independent (differently to all the other EPACs). Collected biometric data that lead to the algorithm design are presented in detail focusing particularly on human metabolic efficiency measurement. Finally, an experiment performed in cycling track compares the mechanical and metabolic results between traditional and hybrid electric bike.

Adaptive position–pressure control of a brake by wire actuator for sport motorcycles

Abstract In this work the control of an electro-hydraulic brake by wire system is presented. The actuator is composed of an electric motor, a mechanical transmission, a hydraulic pump and a pipeline connected to the brake caliper. The highly nonlinear, time-varying relationship between pump piston position and plant pressure ismodelled, showing how the closed loop performances degrade without considering it. A hybrid position–pressure switching controller that aims at coping with the mentioned non-linearity is proposed. A position–pressure map estimation algorithm is introduced; this allows one to make the closed loop system robust with respect to temperature variation and brake pad wear.

An experimentally validated capacity degradation model for Li-ion batteries in PHEVs applications

Abstract This paper proposes an experimentally validated capacity degradation model for Li-Ion batteries deployed in plug-in hybrid electric vehicle (PHEV) applications. An aging and characterization campaign aimed to mimic the real battery usage at low state of charge during charge sustaining operation was conducted on six Lithium iron phosphate (LiFePO4) battery cells. We present an analytical model, driven by experimental data, that relates the main aging factors under which the battery cells have been tested to capacity fade. State-of-health (SOH) and prediction of battery end-of-life (EOL) algorithms can be designed with the proposed model.

Nonlinear parameter estimation for capacity fade in Lithium-ion cells based on a reduced-order electrochemical model

Lithium-ion batteries are central to the powertrain transformation taking place in the automotive industry, but the duration, cost, and complexity of experimental work for the characterization of aging mechanisms drive the need for models and model-based estimation approaches. This paper presents a model-based nonlinear parameter estimation method for the characterization of long-term capacity fade of Lithium-ion cells. The proposed approach relies on a reduced-order model of a LiC6/LiFePO4 cell, describing the mass and charge transfer in the solid and liquid phase, and the governing electrochemical principles. The model, validated with experimental data from a battery cell at beginning of life, is used to conduct a sensitivity analysis of the capacity to a subset of physicochemical parameters that are hypothesized to evolve throughout the batterys life. After isolating the most significant model parameters characterizing the long-term capacity degradation, experimental data from battery aging studies were used to solve a system identification problem to identify the degradation trend for the aging-related parameters. The developed tool is applicable to model-based diagnostic algorithms for ascertaining battery state-of-health and predicting the remaining useful life for Li-ion cells subjected to relevant usage and environmental conditions for automotive applications.

Adaptive Cascade Control of a Brake-By-Wire Actuator for Sport Motorcycles

In this paper, a cascade control architecture for a brake-by-wire system suitable for motor racing applications is described. The system is composed of an electromechanical actuator, i.e., an electric motor, a transmission, a master cylinder, and a traditional hydraulic brake (pipe and caliper). Starting from a control-oriented model, a cascade control is proposed. An inner-loop controls the position; an outer the pressure. The outer loop features an adaptation mechanism to cope with the intrinsic time-varying nonlinearity of the position-pressure relationship. The stability and robustness of the pressure loop are proven. Extensive experimental validation, conducted on an instrumented motorbike on a test circuit by a professional rider, shows the performance of the system.

Adaptive-Robust Friction Compensation in a Hybrid Brake-by-Wire Actuator

This work focuses on the development of a pressure-loop controller for a hybrid brake-by-wire system, composed of a hydraulic link and an electro-mechanical actuator. Towards this goal, we will start by constructing a reduced model that is capable of capturing the fundamental dynamics of the actuator, which is particularly useful for control design purposes. Motivated by the large friction disturbances that affect the system, we also investigate linear-in-the-parameter models suitable for (online) model-based friction compensation. More specifically, results from the theory of function approximation, together with optimization techniques, are explored to approximate the Stribeck friction model through a linear-in-the-parameter model. This new linear-in-the-parameter model is then employed in the design of a control law for tracking the braking pressure of the hybrid brake-by-wire. The main features of this controller are the robustness to parametric uncertainties, thanks to the inclusion of a switching-σ adaptive mechanism, and the attenuation of non-parametric disturbances with a continuous sliding mode action. The stability and robustness properties of the closed-loop system are investigated with the help of the Lyapunov method. Finally, experimental tests demonstrate the effectiveness of the proposed approach and its ability to handle disturbances.

Control-oriented analysis and quality assessment of gear shifting in motorcycles

This paper addresses the analysis of the gear shifting maneuver for motorcycles and it constitutes, to our best knowledge, the first contribute to study this aspect in two-wheeled vehicles. Specifically, a comparison between automatic and manual gear shifting is discussed, based on which some cost functions are proposed to quantitatively evaluate the maneuver quality from measured data. Based on such cost functions, we are able to automatically classify the performed maneuver and label it with a quality attribute matching that assigned by the rider.

Nonlinear Pressure Control for BBW Systems via Dead-Zone and Antiwindup Compensation

In the automotive field, brake-by-wire (BBW) systems are electronically regulated actuators, which are capable of applying a desired braking torque to the vehicles wheel. Specifically, the electrohydraulic technology is the most widely used in commercial vehicles, as it offers a good tradeoff in terms of size, weight, and cost. However, control of BBW actuators in such a configuration is a challenging problem for many reasons, among which the most critical are the dead zone due to the fluid reservoir and the input saturation limits of the electric motor that moves the pump. In this paper, a complete control architecture accounting for this nonlinear behavior is presented, where the main components are a linear controller, a dead-zone compensator, and an antiwindup block, designed in a cascade fashion. With such a configuration, the achieved equilibrium point is guaranteed to be globally asymptotically stable, and the overall system shows to be robust with respect to variations of the position-pressure curve. Simulation and experiments on a production prototype are proposed to show the effectiveness of the proposed strategy.

Deadzone compensation and anti-windup design for brake-by-wire systems

Control of BBW actuators is a challenging problem for many reasons, among which the most critical are the dead-zone due to the fluid reservoir and the limits of the electric motor that moves the pump. In this paper, a complete control architecture accounting for this nonlinear behavior is presented, where the main components are a linear controller, a dead-zone compensator and an anti-windup block, designed in a cascade fashion. With such a configuration, the achieved equilibrium point is guaranteed to be globally asymptotically stable and the overall system shows to be robust with respect to variations of the pressure-position curve. Some simulation examples are proposed to show the effectiveness of the proposed strategy.

Automatic Gear Shifting in Sport Motorcycles

Performing safe and effective gear shifts on two-wheeled vehicles in an automatic way is a challenging task, mainly due to the complexity of the system dynamics and the safety-critical aspects of the application. This work offers one of the first contributions in this area, analyzing all the aspects related to this control problem. Specifically, this work provides two main results: an objective quality assessment of the gear-shifting performance and a new gear shift control strategy that optimizes the tradeoff between duration and comfort. The results obtained on an instrumented vehicle confirm the suitability of the proposed approach.