Practical Automatic Tuning of Lag-lead Compensators for Feedback Control Systems

Yu Sheng Lu*, Tsang Shiuan Tsai, Chin Hao Lai

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review


This paper proposes a scheme for auto-tuning a lag-lead compensator to satisfy frequency-domain specifications of a feedback control system. Most previous studies proposed algorithms for tuning either lag or lead compensators. A study presented a self-tuning lag-lead compensator whose proportional gain, however, needs to be set manually. In contrast to previous studies, a fully automated tuning process for a lag-lead compensator is devised in this paper. In the proposed scheme, the plant's frequency responses at specific frequencies are first estimated, and an iterative algorithm adapts all controller parameters. To facilitate the estimation of high loop gain at a low frequency, a notch filter is introduced to the control loop while estimating this high low-frequency loop gain. Without this mechanism, a real-time data acquisition system of a wide dynamic range would be required. In addition to fulfilling the requirements for the low-frequency loop gain and phase margin, another feature of the proposed scheme is the satisfaction of the required gain-crossover frequency. However, the proposed method supposes that the frequency-domain specifications can be met for a plant using a lag-lead compensator, which is the plant's requirement for the proposed method. Experimental results for controlling a voice-coil motor are reported in this paper, showing that the proposed auto-tuner can practically provide a lag-lead compensated system satisfying frequency-domain performance requirements.

Original languageEnglish
Pages (from-to)281-290
Number of pages10
JournalPeriodica polytechnica Electrical engineering and computer science
Issue number3
Publication statusPublished - 2023


  • automatic tuning
  • control system
  • frequency-domain specification
  • lag-lead compensator
  • loop gain
  • stability margin

ASJC Scopus subject areas

  • Software
  • Signal Processing
  • Information Systems
  • Computer Science Applications
  • Computer Networks and Communications
  • Electrical and Electronic Engineering


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