Dynamic Modeling of a Laminated Composite- Material Flexible Robot Arm Made of Short Beams

High-precision assembly tasks are often performed by compact industrial robots with small work envelopes. The end-effector positional accuracy of compact robots can be accurately predicted by considering the links of the robot arm as short beams. In this study, a general procedure to derive a dynamic model for a revolute flexible robot arm, which takes into consideration the rotary inertia and shear deformation effects, is presented. Only the last link of the arm is considered to be flexible and assumed to be fabri cated from laminated composite materials. Hamilton's principle is used to derive the equations of motion. A displacement finite element model based on the Timoshenko beam theory is implemented to approximate the solution. The digital simulation studies predict the deflections at the end effector and examine the combined effects of rotary inertia and shear deformation. Further more, the improvement in the dynamic response of the robot arm resulting from the fabrication of the manipula tor from laminated composite materials is demonstrated.