Three-dimensional loading control of a pneumatic three-universal–prismatic–universal robot

Abstract

Multidimensional force loading has been widely used in the fields of component and material testing. The pneumatic-driven multidimensional force loading parallel mechanism can meet the requirements of complex force loading. A three-dimensional loading robot based on a pneumatic three-universal–prismatic–universal parallel mechanism is designed to apply time-varying three-dimensional loads on a target. Based on the principle of vector superposition, inverse and forward kinematics are deduced. A second-order mathematical model of a metal seal pneumatic cylinder driven by a flow proportional valve is established. Based on the immersion and invariance technique, the leakage flow in the cylinder is taken as the interference term and estimated. Meanwhile, because of the strong nonlinearity of the actuator, based on suitable disturbance estimation, the control rate of the system is designed through the sliding mode surface, and the stability of the control algorithm is analyzed on the basis of the Lyapunov stability theory. The experimental results show that the immersion and invariance controller exhibits a better control performance than the proportional–integral–differential controller: the steady-state control mean square error is reduced by approximately 21% on average and the dynamic (0.2 Hz) tracking mean square error is approximately 10.35 N.

Projeto E Acionamento De Um Robô Lagartixa Pneumático Com Aplicação De Aprendizado Computacional

“…Com relação aos sistemas pneumáticos, em [13][14][15][16][17][18][19][20] é possível notar a versatilidade destes tipos de sistema, que utilizam ar comprimido como fonte de energia. Estas pesquisas contam com projetos e modelagem, controle e testes nos robôs, que servem para funções variadas.…”

“…Liu, Y. et al [17] projetaram um robô paralelo pneumático de juntas prismáticas, além de terem sido feito seu modelo matemático e controle através de válvulas proporcionais de fluxo. Bai et al [18] desenvolveram a modelagem completa de um robô pneumático de seis patas, além de implementação de controle.…”