## 1 Introduction  
Model-based simulation studies can be the basis for selecting the optimal parameters of a mobile robot, so they are an important tool in the process of designing new solutions. The robot model can be used both at the design stage and in the case of existing robots when designing and optimizing their motion control systems, as well as for energy-efficient path planning. Knowledge of the real parameters of the robot may allow for increasing the accuracy of simulation research. These parameters can be obtained in the identification process. The key geometric parameters determining the driving properties of a wheeled vehicle are those related to the number of wheels and the wheel arrangement, as well as their diameter and width. In turn, an optimally selected control system can allow for the accurate implementation of a desired vehicle movement. One of the key questions that arise at the design stage of wheeled mobile robots is what kinematic structure of the robot should be adopted. This has a decisive impact on the driving properties of the robot and is closely related to the area of its application. As indicated in [PERSON] and Dabek, 2019 [PERSON] (2019), modern wheeled mobile robots belong to one of the following groups: differentially driven, skid-steered, car-like or Ackermann steering, omnidirectional, and rover-type. Skid-steered mobile robots deserve special attention due to their universal application, as they can be used both indoors and outdoors. For this reason, they are most often used in robots for special applications, e.g., for neutralizing improvised explosive devices. However, they have a fundamental drawback--wheel slip is their inherent feature when turning or rotating in place, which adversely affects the accuracy of the movement and energy efficiency. The question arises as to how these negative aspects can be reduced by appropriately selecting the wheel arrangement. Therefore, the aim of this study is to investigate the influence of the wheel arrangement and control system structure of a six-wheeled robot with non-steered wheels on the tracking control accuracy and energy efficiency. To investigate the influence of the wheel arrangement, it would be necessary to analyze a different ratio of the wheel track to the wheel axle distance. For this purpose, a constant value of the wheel axle distance is assumed and various values in terms of the wheel track are analyzed. In addition, the same wheel axle distance is adopted for all robot wheels. The different ratio of the wheel track to the wheel axle distance could also be studied analogously, assuming a constant wheel track and changing the wheel axle distance. As far as the structure of the control system is concerned, one can primarily take into account the control of only the robot's wheels, based on the measurement of the angular velocities of wheel spins, which may allow for achieving a high accuracy of movement in the case of negligible slip of the wheels. Such a control system can also be supplemented with an additional pose controller, i.e., used to control the position and course of the robot based on their measurement or estimation. This may allow for minimizing tracking errors in the case of wheel slip and, consequently, the deviation of the actual robot trajectory from the desired trajectory. In order to achieve the aim of the article, the following key research questions must be answered:  
1. How does the wheel arrangement affect the accuracy of the robot's movement? 2. How does the wheel arrangement affect the energy efficiency? 3. What impact does the choice of control system structure have on the above issues, taking into account the wheels' controller and, additionally, the pose controller? To answer the above research questions using a model-based approach, it is necessary to analyze the robot's kinematics and develop its dynamics model.