Technical Review: Indirect Tire Pressure Monitoring Systems and Tire Vibrations

Indirect tire pressure monitoring systems (ITPMSs) have been an active area of research for the past 2 decades. Researchers worldwide have strived to develop estimation techniques for the detection of the change in tire pressure by using the vibration information present in the speed signal. Different groups have used a torsional vibration model for the tire, owing to its torsional stiffness and rotational moment of inertia. The standard antilock braking system (ABS) speed sensor signal is analyzed for these vibrations. Different estimation algorithms try to detect the change in this vibration frequency, which indicates the change in the torsional stiffness of the tire as a result of variation in the pressure. Tire vibrations have been studied in great detail for the past 5 decades, and there are various models of tire vibrations available in the literature. These models range from physics-based analytical models to finite element models (FEMs). Analytical models take benefit from the mathematics developed for rotating elastic thin shells and plates, whereas FEMs use simulation tools to develop vibration models of the tire. A detailed literature survey of ITPMSs and tire vibration models reveals that there is no correlation between the vibrations detected in the speed signal and the vibrations predicted in the tire vibration models. Researchers have developed tire vibration models that do not take into consideration the effects of vibrations on the speed signal; although, to the best of our knowledge, signal processing and estimation experts who have developed methods for ITPMSs have not validated the true source of observed vibrations in the speed signal and could not present a viable theoretical explanation. In this review, a comprehensive study of the ITPMS techniques and tire vibration models is presented, with an aim to find a correlation between them. The review begins with a brief introduction to the topic followed by state of the art, then a detailed review of ITPMSs and the methods for their realizations in the automotive industry. Finally, tire vibration models are presented in detail, and possible links between vibration models and ITPMS vibrations are sorted.