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The study of the distribution of the deceleration of vehicles of category M1 when performing various maneuvers is intended to develop methods for assessing the parameters of maneuvering of cars in the study of the circumstances of the occurrence of road accidents. Experimental studies were carried out on passenger cars, which are equipped with automated braking force control systems, for various driving styles. M1 category vehicles were maneuvered on dry asphalt pavement in the range of speeds from 11 to 25 m / s, which is typical for most road traffic accidents. It was found that when braking a vehicle of category M1, longitudinal deceleration increase according to a second-order polynomial dependence in the range of deceleration variation from 1.39 to 5.86 m/s2.

The use of electric energy to drive the drive wheels allows you to improve not only the environment, but also the performance indicators of cars. A hybrid car uses both thermal energy from an internal combustion engine (ICE) and electrical energy from generators or batteries. The authors of the paper have conducted a study on the dynamics of a hybrid car, in which ICE energy is used to charge rechargeable batteries, and the latter provide the driveline. By reducing the amplitude of the traction force oscillations, the energy costs for the forward movement of the car are reduced. The purpose of the study is to determine the energy savings for accelerating a car with a combined power plant with electric engines on wheels using battery power. As a result of the study, a mathematical model of the car acceleration process with a combined power plant and powered electric engines of the driving wheels from the batteries has been obtained.

The methods and principles of monitoring and diagnosing the parameters of power units are generalized. They allow increasing the wheeled vehicles operational reliability. Systems for monitoring the functional stability parameters of the most sensitive to operating conditions systems and assemblies of machines have been developed on the example of a cylinder-piston engine group and steering. An improved method for diagnosing the steering of an articulated wheeled vehicle, which significantly affects the safety of its use, is proposed based on the use of angular accelerations of sections in the road plane as a diagnostic parameter. The dependence for determining the angular accelerations for the case of the random installation of two sensors of the mobile registration and measuring complex on the machine, which allows increasing the accuracy of measurements, is obtained. Experimental studies to diagnose the steering of wheeled vehicles with various operating times have been carried out.

The dynamic distribution of normal reactions between the axles of the wheeled tractor has a significant impact on the stability against skidding and the wheeled tractor braking effectiveness. At the same time, the clarification of the normal reactions distribution between the axles allows to choose more rational braking forces distribution between the axles. It is shown that the best way to ensure the highest braking efficiency is the braking mode when the rear wheels of the tractor are at the blocking limit. An assessment of the expediency of installing brake mechanisms on only one axle of the tractor was made. The increase of braking efficiency of wheeled tractors with all brake wheels provided that they ensure directional stability is considered. The laws of braking forces distribution between the axles of wheel tractors for different sequence of wheels locking are determined.

One of the reasons for the large number of road accidents on highways in Ukraine [1] is the instability of the braking properties due to the unstable characteristics of the brake mechanisms’ friction pairs. The manufacturer produces new automobiles with installed brake pairs (brake pads and their counter bodies), which have passed long-term tests for the stability of the friction coefficient and braking forces distribution of between the axles. This ensures the compatibility of the friction pairs characteristics for front and rear brake mechanisms according to the criteria of heat resistance. During operation, instead of worn-out brake pads, brake discs and drums, drivers can purchase new ones, manufactured as spare parts. However, in the well-known literature there are no methods that allow to check the compatibility of the friction pairs characteristics for front and rear brake mechanisms according to the criteria of heat resistance.

The solution to the problem of stability of a multi-axle vehicle during braking is connected with the determination of the dynamic distribution of normal road reactions between the axles. To assess the stability of the vehicle is used as an indicator of the stability factor representing the ratio of the stabilizing moment to moment, the perturbing skid. When the values of the stability coefficient is greater than or equal to unity, the movement is stable, and otherwise it is unstable. For a multi-axle vehicle, determining the dynamic normal road reactions on the axles is possible after disclosing the static uncertainty of the physical model of the car, which is a multi-support beam. The solution to this problem involves the use of the "three sigma" rule.

The intensive development of tractor-building industry in the world has led to the widespread use of wheeled tractors and tractor trains in transportations on public highways. This requires an increase of engine capacity and speed of tractor trains, as well as strict demands for their braking systems. The formation of the necessary braking properties of wheeled tractors and tractor trains on their basis should be carried out at the design phase, taking into account a wide range of aggregated machines and tools. Blocking the wheels of the trailer with different sequence of their blocking and blocking the wheels of the tractor has significant impact on the total braking force, deceleration and stability of the tractor train. It is advisable to take this into account when modeling the braking process of a tractor train.

The bulk of automobiles are equipped with ABS currently. Having of automatic devices that prevent vehicle wheels from locking and skidding does not require consideration of the normal reactions on the front and rear vehicle axles wheels’ changes dynamics. However, ABS malfunction is possible for various reasons, and in this case the braking system must provide the safety vehicle braking. To provide this, it is necessary to return to the problem of choosing the rational braking forces distribution between the wheels of the front and rear axles.

New solutions for actual problems of determination the efficient distribution of braking forces between the axles of the vehicle, and the stability and drivability of two-axles vehicles at service braking are received in the thesis. It permitted for the first time to determine the Law of distribution of the braking forces between the axles, that ensuring straight-running stability of two-axle vehicle at service braking, to obtain the ideal characteristics for the braking system of two-axle vehicle at service braking and to determine possible values for the distribution of braking force on the front axle. The drivability criterion at service braking obtained further development; it is offered to use boundary at gripping front or rear wheels angular vehicle acceleration on the road.

The results of this work is allowed to identify a number of cybersecurity threats of the automated security-critical automotive systems, which reduces the efficiency of operation, road safety and system safety. Wired or wireless access of the information networks of the modern vehicles allows to gain control over power unit, chassis, security system components and comfort systems. According to the evaluating criterion of board electronics, the presence of poorly-protected communication channels, the 75% of the researched modern vehicles do not meet the minimum requirements of cybersecurity due to the danger of external blocking of vital systems. The revealed vulnerabilities of the security-critical automotive systems lead to the necessity of developing methods for mechanical and electronic protection of the modern vehicle. The law of normal distribution of the mid-points of the expert evaluation of the cyber-security of a modern vehicle has been determined.