**5. Conclusions**

This book chapter gives a brief summarization of the research articles from eclectic sources like journal, patents and masters-PhD thesis published in last 5 years on piezoelectric ultrasonic motors. This article gives us the statistical analysis of number of publications on ultrasonic motors with respect to year of publication, country of origin & list of top 10 research journal. It divides all the articles into different categories and highlights the challenges, opportunities & research carried out. It broadly classifies the research article in areas like new design, modeling & simulation, friction & wear, piezoelectric materials, thermal performance & USM applications. Further it introduces with concept of Industry 4.0 & its key enabling technologies. It explains how to apply industry 4.0 technologies like digital twins & simulations, big data & machine learning, Industrial internet of things, additive manufacturing & augmented reality to improve the design & performance of the USM and how USM can best fit in Industry 4.0 era. Ultrasonic motors have tremendous potential for the improvement & Industry 4.0 technologies has tremendous potential to improve its design & performance on the other hand USM has many advantages & wide application areas which can be best suited for industry 4.0 settings. Thus, both USM & industry 4.0 if amalgamated together can give us a remarkable output in future.

*The Roles of Piezoelectric Ultrasonic Motors in Industry 4.0 Era: Opportunities & Challenges DOI: http://dx.doi.org/10.5772/intechopen.100560*
