Law of optimal control of power supplied to wheeled vehicle running gear when moving linearly

Abstract

Introduction (problem statement and relevance). Energy efficiency is one of the most important properties of present-day vehicles. Energy efficiency increasing allows reducing the costs for vehicle movement and for cargo and passenger transportation respectively, as well as decreasing harmful environmental impact. Vehicle energy efficiency increasing can be achieved in different ways, including by optimizing the law of control of the power supplied to the running gear in order to decrease energy consumption for motion caused by wheel slipping (spinning). The research objective is to increase the wheeled vehicle energy efficiency by means of optimal control of the power supplied to the running gear.Methodology and research methods. Vehicle driving inevitably consumes energy, part of which ensures tractive or propelling force generation in the driving wheels when overcoming resistance to motion, while other part is spent to transform energy supplied to the running gear and losses for wheel slipping. Thus, a vehicle energy efficiency increase can be reached by optimal control of the power supplied to the running gear. The loss power in the process of vehicle motion when interacting with the environment is used as a target function in solving this optimization problem. Besides decreasing the energy costs or consumption for the motion, the required vehicle traction level shall be ensured in order to ensure the driving speed mode set by the driver. In this regard, when solving the optimization problem the equality-type constraint describing the mentioned condition shall be taken into account. The method of Lagrange multipliers is used to solve the optimization task.Scientific novelty and results. When developing the control law for the power supplied to the running gear, one shall use additional information on interaction of the wheels with the supporting surface. An additional source of information here is the axial force on the wheel axis measured by installation of the force measuring (dynamometrical) wheels that are an integral part of the wheeled vehicle design. The developed control law for the power supplied to the running gear allows ensuring higher energy efficiency of a vehicle, thereby leveling the disadvantages of the known transmission types with a coupled and individual drive: locked, differential and individual distributing tractive effort torques between the wheels in proportion to the actual normal loads.Practical significance. Application of the developed control law for the power supplied to the running gear will allow, using a common transmission control approach, ensuring of high traction properties under various conditions as well as reduction of energy costs for vehicle motion without requiring additional differential lock control, in case of differential interconnections, and will also allow prevention of additional tyre wear or transmission element malfunction when power circulation occurs in case of a locked drive.