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Relevance There are data in the literature describing the trajectory of displaced center of rotation of the knee joint. However, data on the exact location of instantaneous centers of rotation at various angles of the knee flexion are not available. Objective To identify the localization of instantaneous centers of rotation at various angles of the knee flexion and present the results in the form of a template. Material and methods The bench testing was performed using a specially developed device that provides fixation of the anatomic cadaver preparation of the lower extremity. The device made it possible to identify the zero instantaneous center of rotation using a radiographic positive marker. Control radiographs were performed to determine the "movement" of instantaneous centers of rotation at every 10° of flexion to reach an angle of 120°. The exact location of instantaneous centers of rotation at different knee flexion angles were obtained with a graphical editor and tibia internal rotation identified during the knee flexion. Results The identified instantaneous centers of rotation were applied to the contour of the distal femur to form the template and allow scaling. Conclusions The template developed could be useful for computer hexapod assisted orthopaedic surgery in the treatment of knee stiffness, for mechanotherapy and joint replacement.

Skid-steering mobile robots are widely used because of their simple mechanism and robustness. However, due to the complex wheel-ground interactions and the kinematic constraints, it is a challenge to understand the kinematics and dynamics of such a robotic platform. In this paper, we develop an analysis and experimental kinematic scheme for a skid-steering wheeled vehicle based-on a laser scanner sensor. The kinematics model is established based on the boundedness of the instantaneous centers of rotation (ICR) of treads on the 2D motion plane. The kinematic parameters (the ICR coefficient , the path curvature variable and robot speed ), including the effect of vehicle dynamics, are introduced to describe the kinematics model. Then, an exact but costly dynamic model is used and the simulation of this model’s stationary response for the vehicle shows a qualitative relationship for the specified parameters and . Moreover, the parameters of the kinematic model are determined based-on a laser scanner localization experimental analysis method with a skid-steering robotic platform, Pioneer P3-AT. The relationship between the ICR coefficient and two physical factors is studied, i.e., the radius of the path curvature and the robot speed . An empirical function-based relationship between the ICR coefficient of the robot and the path parameters is derived. To validate the obtained results, it is empirically demonstrated that the proposed kinematics model significantly improves the dead-reckoning performance of this skid–steering robot.