Kinematic/dynamic analysis and optimization of a 2-URR-RRU parallel manipulator

Reduced Dynamic Modeling for Heavy-Duty Hydraulic Manipulators With Multi-Closed-Loop Mechanisms

“…is the Jacobian matrix of the serial mechanism, and given that the serial mechanism has two degrees of freedom, the Jacobian matrix has two columns; P G      is given in Appendix B, which can be obtained by looking up Table 2 [42,44]. 1 2…”

“…3 J should be a 2 2  matrix; (1) 3 H must be a 2 2 2   matrix. Equation (17) can be simplified as…”

“…where (1) 3 H . Equation (18) expresses the forward kinematics that can facilitate the formulation of the Hessian matrices by screw theory.…”

“…Hydraulic systems are widely used in the industry, especially in large machinery, because of their ability to handle large inertia and torque loads. Multi-closed-loop manipulators, such as a class of parallel manipulators [1][2][3][4], are characterized by high stiffness, high accuracy, and high payload-to-weight ratio [4]. Therefore, hydraulic multiclosed-loop manipulators, integrated hydraulic actuators with a complex multi-closed-loop mechanical structure, have found promising applications in many heavy-duty applications, such as excavators, forging manipulators, palletizing robots, parallel manipulators, and so on [5][6][7][8].…”

“…Specifically, when integrated with hydraulic actuator dynamics, the dynamic behaviors of these manipulators can be highly nonlinear and complicated, causing difficulties in the control of such systems. Due to the complex topological structure of multiclosed-loop robotic manipulators or parallel robots, the dynamic modeling problem of these robotic mechanical systems has received increasing attention over the past decades [1,2,[9][10][11][12]. However, most existing dynamic models on the complex multi-closed-loop mechanism mainly aim to achieve its optimal design and performance analysis [11][12][13][14].…”