Dynamics and Control of Underactuated Systems

Dear Colleagues,

Recently, interest has grown in the research field of underactuated systems. A system is said to be underactuated if the number of degrees of freedom within it is greater than the number of independent actuators. In industrial high-performance applications, this property occurs for several reasons. Firstly, it develops as a consequence of weight- or cost-driven design methodologies that fulfill some predefined specification, leading to a reduction in the number of required motors. Secondly, underactuation can arise due to the failure of one or more actuators. Lastly, in order to lower energy consumption and, for instance, fulfill one of the goals regarding the United Nations 2030 Development Agenda, the mass of the components should be significantly lowered. This yields lightweight, highly flexible components and renders underactuation less negligible. By taking all these possible situations into account in order to ensure good performances in the presence of underactuated systems, proper dynamic modeling and control strategies must be developed.

In this light, this Special Issue aims to present advances in both the dynamic modeling and control of underactuated systems.

Papers are welcome on topics that are related, but not limited, to:

• Motion planning;
• Inverse dynamics for underactuated systems;
• Control of nonminimum-phase mechanical systems;
• Feedforward control for mechanical systems;
• Model predictive control for mechanical systems;
• Active vibration control;
• Parameter estimation and model updating;
• Modeling and control of underactuated systems;
• Modeling and control of flexible systems;
• Modeling and control of underactuated multibody systems;
• Underactuated robots;
• Cable-driven robots.

We look forward to your valuable contribution.

Dr. Iacopo Tamellin
Dr. Jason Bettega
Guest Editors

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Actuators is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2400 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

• underactuated systems
• motion planning
• control of underactuated systems
• dynamics of underactuated systems
• inverse dynamics
• flexible systems
• vibration control

Title: Adaptive PID Control of a Quadrotor using Hybrid Particle Swarm Optimization
Authors: Ishaq Hafez; Rached Dhaouadi
Affiliation: American University of Sharjah, UAE
Abstract: This paper presents a novel solution to enhance quadrotor maneuvering and stabilization using a Hybrid Particle Swarm Optimization with Quasi-Newton (HPSO-QN) method for PID controller design. This advanced technique combines the global search capabilities of Particle Swarm Optimization (PSO) with the local search abilities of the Quasi-Newton (QN) method to estimate the optimal gains for controlling altitude and position trajectories. The tuning process is guided by an objective function that minimizes the mean squared error between the estimated and targeted state references. When compared to standard PSO algorithms, the HPSO-QN method shows significant improvements in terms of robustness and precision. These improvements underscore the effectiveness and potential of the HPSO-QN approach for complex control systems in quadrotors.

Title: Dynamic Output Feedback of Second-Order Systems: An Observer-Based Controller with LMI Design
Authors: Danielle Silva Gontijo; José Mário Araújo; Luciano Antonio Frezatto; Fernando de Oliveira Souza
Affiliation: 1. Universidade Federal de Minas Gerais, Programa de Pós-Graduação em Engenharia Elétrica, Minas Gerais, BR 2. Instituto Federal da Bahia, Grupo de Pesquisa em Sinais e Sistemas, Bahia, BR 3. Universidade Federal de Minas Gerais, Departamento de Engenharia Eletrônica, Minas Gerais, BR
Abstract: In this paper, an LMI design to control uncertain second-order systems subject to perturbation in the state via dynamic output feedback is approached. A Luenberger-like descriptor observer to reconstruct the system state is then introduced, and LMI conditions to robust PD-feedback control using the state estimation are applied to compute an optimal parameterized observer gain. The proposed approach can be applied to complete or underactuated systems under the hypothesis that the mass matrix is non-singular. A numerical example and an experimental implementation for the stabilization of a mini-inverted pendulum are given to show the proposal's effectiveness.