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Normal and longitudinal dynamics of vehicles interrelates via the normal and longitudinal tire reactions. The normal reactions are supposed to be formed by characteristics of the suspension system and tires, and the longitudinal forces in the tire patches are produced by the driveline system by supplying torques to the drive wheels. Usually, the normal and longitudinal reactions, independently generated by the two vehicle systems, are considered to interrelate, but not to impact each other. An analytical study presented in this paper showed that the normal tire reactions are formed not only by the design of suspension but also by the longitudinal tire reactions (circumferential wheel forces), which follow from the wheel torques supplied by the driveline system. A 6×6 vehicle with A-type suspension systems at all three axles exhibits different normal tire reactions at the drive axles during motion even when the static weight distribution is equal.

While much research has focused on improving terrain mobility, energy and fuel efficiency of terrain trucks, only a limited amount of investigation has gone into analysis of power distribution between the driving wheels. Distribution of power among the driving wheels has been shown to have a significant effect on vehicle operating characteristics for a given set of operating conditions and total power supplied to the wheels. Wheel power distribution is largely a function of the design of the driveline power dividing units (PDUs). In this paper, 6×6/6×4 terrain truck models are analyzed with the focus on various combinations of PDUs and suspension systems. While these models were found to have some common features, they demonstrate several different approaches to driveline system design.

The field of Vehicle Dynamics as the theory of a vehicle in motion is to study the vehicle's properties (vehicle running abilities) in the interaction of the vehicle and it's surroundings. This interaction itself appears through forces acting on a vehicle. To control these forces leads to control the properties of a vehicle in motion such as tractive and velocity properties, fuel consumption, turnability, ride stability and others. This paper proposes a unique and novel theory of a vehicle in motion. This theory allows parallel control of the forces acting on a vehicle, which leads to considerable improvement of the vehicle's running abilities. This paper presents the interrelation between the criteria of vehicle running abilities and output characteristics of vehicle systems, which control the vehicle forces. To optimize a vehicle's running abilities require optimization of the combinations of forces acting on a vehicle.

When a vehicle moves over uneven ground, motion of the sprung and unsprung masses causes dynamic shifting in the load transmitted to the ground, making the normal reaction in the tire-soil patch a continuously changing wheel parameter that may affect vehicle performance. At high loads, sinkage of the wheel can become high as the wheel digs into the soil. At low loads, the wheel can have difficulty acquiring sufficient traction. Additionally, steerability of the wheel can be diminished at very low loads. Controlling the damping forces in the suspension that is usually used to improve ride quality and stabilize motion of the sprung mass can result in an increase in the dynamic variation of the wheel normal reaction and cause vehicle performance deterioration. In this paper, a method is developed to establish boundary constraints on the dynamic normal reaction to maintain reasonable tire-terrain mobility characteristics.

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.