The National Research Institute of Mechanical Engineering plans to organize the Institute-level Doctoral Thesis Evaluation Council for PhD candidate Tran Si Kien in mid-July 2026. The Institute hereby publishes the information on the doctoral thesis of the PhD candidate as follows:

Full name of PhD candidate: Tran Si Kien

Collective of scientific supervisors: Dr. Phan Dang Phong and Prof. Dr.Sc. Do Sanh

Field: Mechanical Engineering - Code: 9520103

Training institution: National Research Institute of Mechanical Engineering - Ministry of Industry and Trade

Doctoral thesis information on the topic: “Dynamics and optimal motion control of industrial manipulators based on Pontryagin's maximum principle” by PhD candidate Tran Si Kien

Summary of new conclusions of the thesis

1. Scientific significance

• Research and establish the theoretical basis and methodological framework for the optimal control problem of industrial manipulators.
• Determine the optimal control effort trajectory for several manipulator models, thereby clarifying the applicability of the approach using Pontryagin's principle in the study of optimizing the motion of industrial manipulators.
• The topic will contribute several results to the research direction on optimal control of open-chain robot manipulators.
• The theoretical research method combined with simulation presented in the topic can serve as a reference basis for scientific research on robot manipulator control.
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2. Practical significance

The proposed research method can support the selection of motion strategies towards reducing control effort and improving the working efficiency of manipulators in industrial operation processes.

• The research results of the thesis can provide a reference basis for input parameter sets, dynamic models, cost functions, and simulation data for subsequent studies on intelligent control and data-driven robot motion optimization.
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3. New contributions of the thesis

• Propose a methodological framework for the problem of dynamic analysis and optimal motion control of industrial manipulators. Based on the inheritance of known methods including the transmission matrix, the matrix-form Lagrange equation, the compatibility principle, and Pontryagin's maximum principle, the thesis organizes and combines these methods into a unified procedure to establish kinematic and dynamic models, handle trajectory constraints, and determine optimal control conditions. The novelty lies in the integration of the aforementioned theoretical tools within the same methodological framework directly serving typical motion problems of industrial manipulators.
• Establish optimal control problems for several typical motion types of industrial manipulators, considering given target point conditions and motion trajectory constraints. Different motion types are formulated within the same optimal control framework, directly considering the dynamic structure of the manipulator, load variations between the forward and return phases, as well as the influence of the execution time of each stage, rather than being described merely as individual geometric trajectory planning problems.
• Verify the optimal control law through numerical simulation for several typical planar manipulator models, providing quantitative comparisons of optimality criteria with certain motion laws and other methods, thereby illustrating the applicability of the proposed method.

View the detailed content of the thesis of PhD candidate Tran Si Kien here