1,722,178 research outputs found
Optimal torque management strategies for all-wheel-drive electric motorcycles
No full textThe need for more sustainable mobility is fostering the electrification of all types of road vehicles. Electrification has also led to increased interest in multi-motor solutions for all-wheel-drive powertrains, to the benefit of handling and stability, and offering the possibility of reducing energy usage thanks to the optimisation of multi-motor torque management. This paper investigates whether the energy efficiency of a dual-motor, all-wheel-drive electric motorcycle is greater than the efficiency of a standard single-motor, rear-wheel-drive one. A mathematical model for the estimation of the driving losses is presented first. The model is then used to develop an optimal torque management strategy that minimises powertrain losses under propulsion as well as a strategy that maximises energy recovery under braking. A case study is used to quantitatively assess the proposed strategies, which are also compared to the performance of standard rear-wheel-drive motorcycles both in terms of energy efficiency and riding safety. Simulation results highlight that the all-wheel-drive electric motorcycle outperforms the rear-wheel-drive both in terms of energy efficiency and tyre-road friction usage. Overall, the maximisation of energy efficiency or safety–depending on specific driving conditions–is achievable with a feed-forward torque management system
Series Hybrid Electric Vehicle Simultaneous Energy Management and Driving Speed Optimization
Full text linkThe energy management (EM) and driving speed
co-optimization of a series hybrid electric vehicle (S-HEV) for
minimizing fuel consumption is addressed in this article on the
basis of a suitably modeled series powertrain architecture. The
paper proposes a novel strategy that finds the optimal driving
speed simultaneously with the energy source power split for
the drive mission specified in terms of the road geometry and
travel time. Such a combined optimization task is formulated
as an optimal control problem that is solved by an indirect
optimal control method, based on Pontryagin’s minimum principle. The optimization scheme is tested under a rural drive
mission by extensive comparisons with conventional methods that
deal with either speed optimization only or EM strategies with
given driving cycles. The comparative results show the superior
performance of the proposed method and provide further insight
into efficient driving
Investigating Alternative Phase Planes for Assessing Vehicle Stability
No full textThis paper discusses the possibility of assessing vehicle stability by means of unconventional graphical methodologies and defining a region of stability of the vehicle, using only yaw rate, lateral acceleration and sideslip rate. The three-dimensional β-r-β ̇ phase surface is investigated, relating trajectories in the r-β ̇ plane to their β values. The r-β ̇ phase plane is investigated for different tyre models and tyre-road friction conditions. A new stability region is proposed
Extending the range of Plug-in Hybrid Electric Vehicles by CVT transmission optimal management
No full textOptimisation of off-road motorcycle suspensions
No full textOff-road motorcycle suspensions are subjected to severe solicitations like large jumps and bumps. Its optimisation requires assessing comfort and handling for which several indices can be found in the literature. However these indices were developed for other vehicles and it is not clear how they behave assessinglarge obstacles. To investigate this, four comfort indices and four handling indices are used to assess the performance of a motorcycle modelled with two degree of freedom under continuos and impulsive off-road excitations. It is found that the best suited indices are the Vibration Dose Value for comfort and the eighth order mean value of the contact force for handling. Additionally, these indices are used to optimise the damping on a five degree of freedom model of a motorcycle, with which is found that on each road scenario, the optimal damping is in between the damping for optimal comfort and optimal handling, and the final selection depend on the relative preference between both objectives
Gyroscopic stabilisers for powered two-wheeled vehicles
Full text linkThis paper illustrates the potential of a gyroscopic stabiliser for the stabilisation of single-track vehicles, at low and high speed as well as during braking. Alternative systems are considered, including single and twin counter-rotating gyroscopes, spinning and precessing with respect to different axes, either freely (passive stabilisers) or in a controlled way (active stabilisers). A suitable mathematical model has been developed and stability has been investigated both by eigenvalue calculation and time domain simulations. It has been found that the most effective configuration is one where the gyroscope(s) spin with respect to an axis parallel to the wheels' spin axis and swing with respect to the vehicle yaw axis. Passive systems may effectively stabilise both weave and wobble at medium and high speed, but cannot stabilise the vehicle at low and zero speed. On the contrary, actively controlled gyroscopes are capable of stabilising the vehicle in its whole range of operating speed, as well as during braking. The alteration of the original vehicle handling characteristics is negligible when active counter-rotating gyroscopes are used, and still acceptable if a single gyroscope is adopted instead
A curvilinear abscissa approach for the lap time optimization of racing vehicles
No full textThe optimal control and lap time optimization of vehicles such as racing cars and motorcycle is a challenging problem, in particular the approach adopted in the problem formulation has a great impact on the actual possibility of solving such problem by using numerical techniques. This paper illustrates a methodology which combines some modelling technique which have been found to be numerically efficient. The methodology is based on the 3D curvilinear coordinates technique for the road modelling, the moving frame approach for the derivation of the vehicle equations of motion, the replacement of the time with the position along the track as new independent variable and the formulation and the solution of the minimum lap time problem by means of the indirect approach. The case study of a GT car is presented and simulation examples are given and discussed
Green driving optimization of a series hybrid electric vehicle
Full text linkThis paper develops an indirect optimal control methodology to achieve green driving optimisation for series hybrid electric vehicles. Starting from a given vehicle mission, specified in terms of a road journey that has to be completed in a given amount of time, the power sharing among the powertrain sources and the vehicle speed profile along the journey are optimised and found. The scheme combines parametric modelling of the vehicle and powertrain together with computationally efficient optimal control software to provide an optimization strategy that works in real-time. Simulation results that demonstrate the success of the method and provide further insight into efficient driving, are presented
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