Active vibration control of a flexible parallel manipulator 3RRR

Author(s)

Geronel, Renan Sanches ; de Oliveira, Gustavo Correa ; Rodrigues, Gabriel Konda ; da Silva, Maira Martins

• Document type: Journal article
• Source: ROBOTICA; v. N/A, p. 19-pg., 2025-05-19.

Abstract

Parallel manipulators (PMs) are adopted in different fields due to their superior characteristics compared to serial manipulators. PMs with flexible links are likely more energy efficient and have high dynamic performance since they are lighter than those with rigid links. On the other hand, due to their lightweight design, the flexibility can lead to undesired deformation and vibration, decreasing the tracking trajectory and transient errors. This work proposes a two-loop active vibration control strategy, using strain gauges and piezoelectric lead zirconate (PZT) actuators, to compensate for the undesired effect of the flexibility. A pose control loop exploits the sliding mode control using data collected from images acquired by an oCam-5CRO-U camera, while the active vibration control loop uses strain gauge sensors and PZT actuators. Strain gauges are responsible for measuring the deformation of each link, and after being treated by digital filters, these signals are applied to the PZT actuator. Combining both loops allows the manipulator to be guided over the desired trajectory with positive vibration attenuation. The results reveal that the presence of the PZT on both sides of the flexible links increases the links' rigidity, yielding overshoot and vibration reduction during the manipulator's motion. In addition, the maximum peak is significantly attenuated, and the overall oscillations are also positively reduced when using the two-loop active control strategy. The root mean square error quantifies this attenuation, showing an average reduction of 30% in the corresponding step input directions. Therefore, the proposal improves the system performance by enhancing the tracking trajectory with lower vibrations. (AU)

• FAPESP's process: 23/00687-8 - Performance improvement of smart metastructures for broadband vibroa-coustic control
• Grantee: Gabriel Konda Rodrigues
• Support Opportunities: Scholarships in Brazil - Post-Doctoral
• FAPESP's process: 18/21336-0 - Towards high speed parallel kinematic machines, Phase II: instrumentation, modeling and control of a flexible manipulator
• Grantee: Maira Martins da Silva
• Support Opportunities: Regular Research Grants
• FAPESP's process: 22/06816-1 - Dynamic Model-Free Control of Parallel Planar Manipulators with Flexible Links
• Grantee: Gustavo Corrêa de Oliveira
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 23/07834-6 - Digital Twins: an integrated approach for modeling and controlling Flexible Manipulators
• Grantee: Renan Sanches Geronel
• Support Opportunities: Scholarships in Brazil - Post-Doctoral