Design and evaluation of robust controllers for the impedance control of hydraulic actuators with accumulators

• Grant number: 25/03051-2
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: May 01, 2025
• End date: April 30, 2026
• Field of knowledge: Engineering - Mechanical Engineering
• Principal Investigator: Hélio Jacinto da Cruz Neto
• Grantee: André Araújo Fernandes
• Host Institution: Escola de Engenharia de São Carlos (EESC). Universidade de São Paulo (USP). São Carlos , SP, Brazil

Abstract

Mobile robotics plays a crucial role in technological advancement, with robots increasingly being employed in challenging tasks. Many of these applications require interaction with the environment, such as inspection, industrial processes, and cooperation with humans. In these cases, it is ideal for the robot to have a compliant behavior, ensuring a safe and effective interaction. Impedance control is a fundamental approach to modulate this interaction. However, in robots with hydraulic actuators, its implementation presents additional challenges due to the nonlinear dynamics and uncertainties inherent to these systems. This project aims to develop and evaluate strategies to enable the efficient application of impedance control in hydraulic actuators, mitigating these difficulties. Two approaches will be investigated: robust control and hydraulic accumulators. The first aims to guarantee performance and stability in the presence of uncertainties at the impedance loop. The second should attenuate sudden changes in pressure signals, potentially aiding control performance. The evaluation of these approaches will consist of their numerical and experimental implementation. In the numerical evaluation, the model and controllers will be implemented in MATLAB/Simulink environment, while the experimental evaluation will be conducted on the test bench with hydraulic actuators of the legged robotics laboratory of EESC-USP. The comparison between cases with and without the proposed approaches will allow an analysis of their impact on the controllers' performance. It is expected that this study will contribute to the improvement of impedance control in hydraulic systems, expanding its applicability in mobile robots.