Modelling and analysis of selected platform dynamics issues of a land robot

The research object is a land robot designed to perform special tasks. One of the robot's elements is a six-wheeled platform with independent suspension. The platform allows the robot to move on land and overcome obstacles. Any equipment enabling the robot to perform planned tasks can be mounted on it. If the implementation of the mission requires the platform to move in uneven terrain, external forces are generated resulting from the platform's wheels overcoming uneven road surfaces. Disturbances occurring in the system may negatively affect the measuring and actuating devices mounted on the platform. Actuator devices may also cause additional excitations. This may lead to disruptions in the process of the land robot carrying out its intended work. The aim of the work is to analyse selected dynamics issues with particular emphasis on the modal analysis of the land robot platform and, on this basis, to check the correctness of its design. In order to carry out the tasks set, a physical and mathematical model of the platform was developed. The energy method was used to derive the analytical relationships, which requires the determination of the kinetic energy, the potential energy, the dissipative Rayleigh function and external non-potential forces. A modal analysis was carried out to determine the dynamic parameters of the system and its susceptibility to the generated excitations was determined. The considerations carried out allow for the design of a structure that improves comfort for the actuating devices. Thanks to the developed model, it is possible to select the values and distribution of system parameters in such a way as to exclude the phenomenon of beating and resonance. In the general case, the robot's basic motion is coupled to the disturbances generated in the system. That's why the considerations carried out in this paper are so important, which enable the development of robot platform dynamics that minimize the impacts on the robot's realized fundamental motion.