Abstract
By a News Reporter-Staff News Editor at Robotics & Machine Learning Daily News Daily News-Investigators publish new report on Ro botics. According to news reporting originating in Padua, Italy, by NewsRx journ alists, research stated, "Differentially flat under-actuated robots are characte rized by more degrees of freedom (DOF) than actuators: this makes possible the d esign of lightweight cheap robots with high dexterity. The main issue of such ro bots is the control of the passive joint, which requires accurate dynamic modeli ng of the robot.Friction is usually discarded to simplify the models, especially in the case of low-speed trajectories." The news reporters obtained a quote from the research from the University of Pad ua, "However, this simplification leads to oscillations of the end-effector abou t the final position, which are incompatible with fast and accurate motions.This paper focuses on planar $n$ -DOF serial robotic arms with $n-1$ actuated rotational joints plus one final passive rotational joint with stiffness and friction properties. These robots, if properly balanced, are differentially flat. When the non-actuated joint can b e considered frictionless, differentially flat robots can be controlled in open loop, calculating the motor torques demanded by pointto- point motions. This pap er extends the open-loop control to robots with a passive joint with viscous fri ction adopting a Laplace transform method. This method can be adopted by exploit ing the particular structure of the equations of motion of differentially flat u nder-actuated robots in which the last equations are linear. Analytical expressi ons of the motor torques are obtained."
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