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Welcome to Dr. Puren Ouyang's Homepage

Teaching Publications Laboratory Education


Puren Ouyang, Ph.D. P.Eng.

Associate Professor
Department of Aerospace Engineering

ENG144, George Velari Engineering Building
Ryerson University
350 Victoria Street, Toronto

Tel: 1-416-979-5000 ext. 4928
Fax: 1-416-979-5056

Research Interests:

Control System

Hybrid System
Micro/Nano Engineering

Current Research Project(s): Contour tracking control in position domain: principle, development, and application

The high complexity, nonlinearity, and wide applications of robotic systems have led to extensive research in the field of robot control. Many control methods have been developed with the goal of achieving high contour tracking and reliable performances. In the applicant’s recent research, the concept of position domain control was introduced in a simple form of PD/PID control laws for robotic systems to improve contour tracking performance as a superior alternative to time domain control.

To build the position domain control system, a multiaxis robotic system is viewed as a master–slave motion system. The master motion is measured and used as a reference that will not produce any error to the final contour error, and the slave motions are described as functions of the master motion according to the contour trajectory requirements. Slave motion control is implemented in position domain based on the master motion.
Theoretical research and systematic development of position domain control systems are necessary in order to promote the new position domain control and its applications in manufacturing industry. This research aims to develop position domain control theory, methods, and applications for contour tracking in manufacturing processes as an alternative that has superior performance than the time domain counterparts.

The long-term goal of this research program is to make position domain control as a core control technology for contour tracking of robotic systems and to improve product quality in manufacturing processes.
The research program aims at developing a general position domain control theory that can integrate the traditional time domain control theory, providing alternative but superior control systems for contour tracking applications, and exploring its applications for hybrid robotic systems.
This research will develop the following enabling technologies to make position domain control a reality and potential applications in manufacturing processes:

 (1) Theoretical study of position domain control to build a united system architecture that can integrate position domain control and time domain control. (2) Development of advanced position domain control systems to expand the control methods developed in time domain to position domain. (3) Testing, verification, and application of the position domain control system in hybrid macro-micro motion systems and hybrid actuation systems.

Past Research Project: Hybrid Macro-Micro Robotic Systems

There are three general research issues in the HMMRS technology. The first issue is about the design of the architecture of the HMMRS. Currently, in macro-micro systems, it seems that the so-called serial architecture is mostly used. The second issue is about the technology to implement the architecture of HMMRS, in particular the technology of control and / or coordination of the whole system. The third issue is the tailoring of the general HMMRS technology to a specific application to further optimize the performance of the specific HMMRS system.

The short-term objectives are proposed to address the aforementioned issues, and they are described as follows:

  1. Study on the HMMRS architecture. In this program, the general hybridization principle will be applied to the HMMRS; in particular a parallel or hybrid architecture to bring macro-scale and micro-scale systems or sub-systems together.
  2. Study on control of the HMMRS. One of the potential problems with the HMMRS is interaction of different technical principles for cross-domain systems with side effects. Philosophically, integration of them together demands a high skill of coordination or control. In particular, I will study hybridization of different control algorithms (e.g., learning-based algorithm, PID, model-based algorithms, etc.). The optimization needs to be done here in the determination of share between the two systems to achieve the target in terms of system bandwidth, accuracy and precision.
  3. Methodology for adapting the general HMMRS technology to a specific application. In the proposed research program, the inspection for the aircraft skin as an example will be developed to verify the HMMRS. A prototype HMMRS with inspection devices such as CCD camera and eddy current testing instrument will be built and first tested in laboratory on a sample aircraft skin, followed by the test on a real fuselage section of the aircraft skin.


  • AER520 -- Stress Analysis
  • AER626 -- Applied Finite Element Method
  • AER507 -- Materials and Manufacturing
  • AER509 -- Control Systems
  • AER723 -- Introduction to Space Systems Design
  • AE/ME8115 -- Advanced Finite Element Analysis
  • AE/ME8137 -- Advanced Systems Control
  • AE/ME8138 -- Computational Dynamics




PhD and Master students positions are avaiable in Mechatronics, Robotics, and Micro manipulation systems. To pursue research in these areas, the candidates should have a bachelor/master’s degree in Aerospace/ Mechanical/ Electrical engineering with a strong background in design, dynamics and control systems, as well as high GPA and TOEFL score.

Interested candidates may contact Dr. Ouyang for details and should send their resumes and three references as well as copies of research papers to