Novel linear algebra model-based position controller for high-precision 4-DOF Parallel robots

Parallel robots (PRs) have gained increasing attention in various fields owing to their inherent capabilities of high rigidity, load capacity, speed, and precision. However, PRs have several limitations because the development of their forward kinematic and dynamic models to implement model-based control schemes is complex. In particular, obtaining a dynamic model for real-time model-based control is challenging owing to the nonlinearity of the model. Thus, a controller for the trajectory tracking of parallel robots is proposed to overcome the current limitations based on a linear algebra-based controller (LABC) design technique that incorporates the dynamic model into the control scheme. The stability analysis of the controller demonstrated that it is globally uniformly asymptotically stable. A real-time position-control scheme based on the proposed approach was implemented in an actual PR to validate and analyze its response. The PR has four degrees of freedom (DOF): two translations and two rotation movements. Simulations and experiments confirm the feasibility and effectiveness of the proposed controller. The proposed strategy allows intuitive adjustment of the parameters, the computational cost is low, and the robot can follow the desired trajectory precisely, obtaining errors of the order of millimeters in linear movements and of the order of tenths of radians in angular movements. This study advances the current state-of-the-art in PR control in the context of model-based trajectory controllers.