Achievement of chaotic synchronization trajectories of master-slave manipulators with feedback control strategy

This paper addresses a master-slave synchro- nization strategy for complex dynamic systems based on feedback control. This strategy is applied to 3-DOF pla- nar manipulators in order to obtain synchronization in such complicated as chaotic motions of end-effectors. A chaotic curve is selected from Duffing equation as the trajectory of master end-effector and a piecewise approximation method is proposed to accurately represent this chaotic trajectory of end-effectors. The dynamical equations of master-slave manipulators with synchronization controller are derived, and the Lyapunov stability theory is used to determine the stability of this controlled synchronization system. In numer- ical experiments, the synchronous motions of end-effectors as well as three joint angles and torques of master-slave manipulators are studied under the control of the proposed synchronization strategy. It is found that the positive gain matrix affects the implementation of synchronization con- trol strategy. This synchronization control strategy proves the synchronization＇s feasibility and controllability for com- plicated motions generated by master-slave manipulators.

Piezoelectric soft robot driven by mechanical energy

Power sources and energy-harvesting schemes are still grand challenges for soft robots.Notably,compared with other power sources,triboelectric nanogenerators(TENGs)have shown great potential because of their low manufacturing and fabrication costs,outstanding resilience,remarkable stability,and environmental friendliness.Herein,a triboelectric effect-driven piezoelectric soft robot(TEPSR)system is proposed,which integrates a rotary freestanding triboelectric nanogenerator(RFTENG)to drive a soft robot comprising a piezoelectric unimorph and electrostatic footpads.Based on the natural triboelectrification,through converting mechanical energy into electricity,TENG provides a unique approach for actuation and manipulation of the soft robot.The perfect combination provides the most straightforward way for creating a self-powered system.Experimentally,under the power of RF-TENG,the soft robot reaches a maximum moving speed of 10 cm per second and a turning rate of 89.7°per second,respectively.The actuation and manipulation demonstration are intuitively accomplished by maneuvering the robot around a maze with a 71 cm track within 28 s.For autonomous feedback controls,one practical application is carrying two infrared sensors on board to realize obstacle avoidance in an unstructured environment.Moreover,a micro-camera was equipped with the soft robot to provide real-time“first-person”video streaming,enhancing its detection capability.