{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,7,8]],"date-time":"2026-07-08T16:05:26Z","timestamp":1783526726291,"version":"3.55.0"},"reference-count":26,"publisher":"MDPI AG","issue":"2","license":[{"start":{"date-parts":[[2021,1,20]],"date-time":"2021-01-20T00:00:00Z","timestamp":1611100800000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":[],"crossmark-restriction":false},"short-container-title":["Entropy"],"abstract":"<jats:p>A simplified fractional order PID (FOPID) controller is proposed by the suitable definition of the parameter relation with the optimized changeable coefficient. The number of the pending controller parameters is reduced, but all the proportional, integral, and derivative components are kept. The estimation model of the optimal relation coefficient between the controller parameters is established, according to which the optimal FOPID controller parameters can be calculated analytically. A case study is provided, focusing on the practical application of the simplified FOPID controller to a permanent magnet synchronous motor (PMSM) speed servo. The dynamic performance of the simplified FOPID control system is tested by motor speed control simulation and experiments. Comparisons are performed between the control systems using the proposed method and those using some other existing methods. According to the simulation and experimental results, the simplified FOPID control system achieves the optimal dynamic performance. Therefore, the validity of the proposed controller structure and tuning method is demonstrated.<\/jats:p>","DOI":"10.3390\/e23020130","type":"journal-article","created":{"date-parts":[[2021,1,20]],"date-time":"2021-01-20T12:16:18Z","timestamp":1611144978000},"page":"130","update-policy":"https:\/\/doi.org\/10.3390\/mdpi_crossmark_policy","source":"Crossref","is-referenced-by-count":43,"title":["A Simplified Fractional Order PID Controller\u2019s Optimal Tuning: A Case Study on a PMSM Speed Servo"],"prefix":"10.3390","volume":"23","author":[{"ORCID":"https:\/\/orcid.org\/0000-0003-0125-7425","authenticated-orcid":false,"given":"Weijia","family":"Zheng","sequence":"first","affiliation":[{"name":"School of Mechatronic Engineering and Automation, Foshan University, 33 Guangyun Road, Foshan 528225, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7006-2122","authenticated-orcid":false,"given":"Ying","family":"Luo","sequence":"additional","affiliation":[{"name":"Department of Mechanical Science and Engineering, Huazhong University of Science and Technology, 1037 Luoyu Road, Wuhan 430074, China"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0002-7422-5988","authenticated-orcid":false,"given":"YangQuan","family":"Chen","sequence":"additional","affiliation":[{"name":"School of Engineering, University of California, Merced, 5200 North Lake Road, Merced, CA 95340, USA"}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Xiaohong","family":"Wang","sequence":"additional","affiliation":[{"name":"School of Automation Science and Engineering, South China University of Technology, 381 Wushan Road, Guangzhou 510641, China"}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"1968","published-online":{"date-parts":[[2021,1,20]]},"reference":[{"key":"ref_1","doi-asserted-by":"crossref","first-page":"101","DOI":"10.1007\/s11071-014-1854-7","article-title":"Numerical simulation for two-dimensional variable-order fractional nonlinear cable equation","volume":"80","author":"Bhrawy","year":"2015","journal-title":"Nonlinear Dyn."},{"key":"ref_2","doi-asserted-by":"crossref","first-page":"650","DOI":"10.1016\/j.cnsns.2014.10.008","article-title":"Using general quadratic lyapunov functions to prove lyapunov uniform stability for fractional order systems","volume":"22","author":"Gallegos","year":"2015","journal-title":"Commun. 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