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An open-link locomotion module, comprising a driving wheel with an electric motor, a system of electro-hydraulic suspension, and an electro-hydraulic power steering system, is presented in this paper as the basis for the modular design of unmanned (robotic) ground vehicles. The open-link-type configuration allows the module to be functionally integrated and engineered with a system of similar modules and thus virtually allows to compile vehicles with any required number of driving wheels. The overall dimensions and carrying capacity of the tire used in the module, as well as technical characteristics of the suspension and power steering systems make possible to employ the module for commercial ground vehicle applications. This paper considers technical issues related to designing the locomotion module.

The main trend in designs of modern automobiles is a widespread use of mechatronic modules and systems. These modules are built as a symbiosis of electric, electronic and hydraulic components, united by means of the control system and intended to fulfill particular targeted functions. In the article results of a comprehensive theoretical and experimental study aimed at creating a drive and a control system of a wheel module intended to be used with the steering and spring systems of an automobile and a mobile robot have been considered. Also the basic principles of the a complex of mechatronic drives of the wheel module (CMD WM) and technical requirements for the components of the complex as a mechatronic module of the system of active safety of the automobile and mobile robot have been formulated.

Two characteristics of terrain mobility are essential in designing an unmanned ground vehicle (UGV): (i) the ability of a vehicle to move through terrain of a given trafficability and (ii) the obstacle performance, i.e., the ability to avoid, interact with and overcome obstacles encountered on a preset route of a vehicle. More attention has been given to the vehicle geometry including selection of the angles of approach and departure, radii of longitudinal and lateral terrain mobility, and the steering system configuration. An essential effect is exhibited by the tire properties in their interaction with the support surface; this, in turn, affects traction properties of the wheel and, thus, vehicle terrain mobility. However, the influence of power distribution between the driving wheels together with vehicle steering system on the two above-listed characteristics of terrain mobility has not been considered in depth.

The aim of this paper is to present the main principles of building the traction electric drive (TED) of the wheels of a heavy-duty road commercial vehicle.A high importance is given to the complex nature of designing and summing up the practical experience of making particular designs of the traction electric drive; as well as to the involved terms and definitions. The design of the AC TED with asynchronous motors and an AC generator looks most promising and having the best price/quality ratio.

The modular designing principle is generally recognized in the automotive industry. However, the issue of building a wheel open-link locomotion module (OLLM) as a combination of steering (wheel turning), springing, traction drive and braking systems is not properly developed yet. An automated control system (ACS) is needed to able to unite and coordinate all the vehicle systems intended to manage the wheel. The automated control system intended to manage the steering and wheel springing parameters is a combination of an information and power channels, through which the wheel is electro-hydraulically driven, and the steering, springing and braking systems are controlled. The number of such channels in a wheeled mover of the vehicle or mobile robot is defined by the wheel type (driving, driven, steered or non-steered wheel). The plurality of such channels forms a complex of automated control systems of the wheeled mover.

An open-link locomotion module (OLLM) is an autonomous energy self-sufficient locomotion setup for designing ground wheeled vehicles of a given configuration that includes drive/driven and steered/non-steered wheels with individual suspension and brake systems. Off-road applications include both trucks and trailers. The paper concentrates on the module's electro-hydraulic suspension design and presents results of analytical and experimental studies of a trailer with four driven (no wheel torque applied) open-link locomotion modules. On highly non-even terrain, the suspension design provides the sprung mass with sufficient vibration protection at low level of normal oscillations, enhanced damping and stabilized angular movements. This is achieved by the introduction of two control loops: (i) a fast-acting loop to control the damping of the normal displacements; and (ii) a slow-acting control loop for varying the pressure and counter-pressure in the suspension system.

An electro-hydraulic servo system makes the basis for a mechatronic locomotion module (LM) and for a complex comprising an LM and an undercarriage of a vehicle. The servo system of the wheel module/LM complex is a combination of the information and power channels of the electro-hydraulic wheel drive within the steering system. A combination of the servo systems makes up a complex of servo systems of the steering system of the multi axis wheel mover of the vehicle. Theoretical and experimental studies of the functioning all-wheel steering were aimed on substantiation the rational algorithmic maintenance of the automatic control system. The results of the study allowed formulating the basic principles of designing and calculating the functionality algorithms for the steering system of the complex of mechatronic modules of the multi-axis vehicle.