Research On Key Technologies Of Multi-axial Vehicle’s Integrated Transmission Performance Test System

Multiaxial vehicles have a very important market and position in some aspects, such as large-scale construction projects, heavy equipment transportation and military weapons. The integrated multiaxial transmission test system which is one of the main test equipments for testing performance and reliability of multiaxial vehicles plays a key role in accelerating new products development of multiaxial vehicles.In this paper, taking the program named "high-power transmission performance test system" as the basis, the design principles of integrated multiaxial transmission test system and a number of key technical issues were analyzed and researched. The researched key technical issues include three aspects. The modeling of test system and the control of multiaxial speed synchronization are the first aspects. Another one is the dynamic modeling of multiaxial vehicle in vehicle’s performance tests. The last one is the multiaxial electrical inertia emulation based on load distribution. The specific contents are as follows:1) According to characteristics and test requirements of integrated multiaxial transmission test system, some design principles of integrated were proposed and illustrated by examples in this paper which involve device parameters, system test process and other aspects of system measurement and control. For device parameter selection, a matching principle of inertia between system devices and experimental objects was proposed to optimize parameters of system devices. For the test process and aspects of measurement and control, a tiered test process of management plus control was used in test system, and a network mode of industrial ethernet plus fieldbus was built for the network of test system. And functions of integrated multiaxial transmission test system were analyzed and classified in order to keep a good real-time performance.2) From the perspective of system control model, the control method of speed synchronization used for integrated multiaxial transmission test system was studied, and an overall modeling method of any test system was proposed. Then taking a overall model of 3 axis vehicle test system as an example, effects caused by the coupling of models, the discrete between devices and the variety of test subjects in multiaxial speed synchronization were analyzed. According to the requirements of the vehicle performance tests, an algorithm was proposed based on differential speed feedback to compensate the load torque of dynamometer motor and achieve the multiaxial speed control. And the simulation analysis by computer showed the feasibility of the algorithm.3) Conduct a comprehensive study of the requirements and characteristics of multiaxial vehicle performance tests in integrated multiaxial transmission test system, three different dynamical model of multiaxial vehicle were proposed to be used in different vehicle performance tests. The vehicle’s single degree of freedom model which considers the forward direction of vehicle as the only one degree of freedom was suitable for vehicle straight performance tests with general road condition. By further increasing two degrees of freedom which were vertical direction and the pitch direction, the vehicle’s three degree of freedom model was proposed to do vehicle straight performance tests with complex road condition. At last but not the least, the vehicle steering model that can be used for simple steering performance tests was proposed after considering test system’s own characteristics. The validity of those vehicle’s models mentioned above was verified preliminarily by using simulation analysis.4) According to the motion state analyzing of multiaxial vehicle, multiaxial electric inertia emulation based on load distribution should be used when doing vehicle performance tests. By theoretical analysis, the calculation method of load distribution coefficient under different driving conditions of vehicle was proposed. According to the structural characteristics of two uniaxial electrical inertia emulation methods which are inverse dynamics method and speed tracking method, the extension methods from uniaxial electrical inertia to multiaxial electrical inertia were proposed. And the feasibility of new methods was proved by simulation analysis and experimental verification.