Research on Piezoelectric Driving Microminiature Three-Legged Crawling Robot

Micro-robots have the characteristics of small size,light weight and flexible movement.To design a micro three-legged crawling robot with multiple motion directions,a novel driving scheme based on the inverse piezoelectric effect of piezoelectric ceramics was proposed.The three legs of the robot were equipped with piezoelectric bimorphs as drivers,respectively.The motion principles were analyzed and the overall force analysis was carried out with the theoretical mechanics method.The natural frequency,mode shape and amplitude were analyzed with simulation software COMSOL Multiphysics,the optimal size was determined through parametric analysis,and then the micro three-legged crawling robot was manufactured.The effects of different driving voltages,different driving frequencies,different motion bases and different loads on the motion speed of the robot were tested.It is shown that the maximum speed of single-leg driving was 35.41 cm/s,the switching ability between different motion directions was measured,and the movements in six different directions were achieved.It is demonstrated the feasibility of multi-directional motion of the structure.The research may provide a reference for the design and development of miniature piezoelectric three-legged crawling robots.

Design of large-displacement asymmetric piezoelectric microgripper based on flexible mechanisms

The output displacement of the traditional symmetrical microgripper is large,but its micro-components or parts are easily damaged due to the uneven force exerted on the left and right jaws of the gripper.The output force of the traditional asymmetric microgripper is stable.However,its output displacement is small,typically half the output displacement of the symmetric microgripper.To solve these problems,in this study,we designed a large-displacement asymmetric microgripper.First,we calculated the relationship between the theoretical input and output variables based on their geometric relationship.Then,we analyzed the performance of the microgripper using finite element software.Lastly,we used a piezoelectric actuator as the input driver of the microgripper.The errors associated with the theoretical and simulated output displacements were 7.05%and 9.24%,respectively.At 150 V of driving voltage,the maximum output displacement was 224μm,and the actual magnificationwas 11.2 times.Microparts can be gripped in parallel and stably,which confirms the validity of the design.

A Piezoelectrically Driven Microrobot Using a Novel Monolithic Spatial Parallel Mechanism as Its Hip Joint

Inspired by the fast,agile movements of insects,we present a 1.9 g,4.5 cm in length,piezoelectrically driven,quadrupedal microrobot.This microrobot uses a novel spatial parallel mechanism as its hip joint,which consists of two spatially orthogonal slider-crank linkages.This mechanism maps two inputs of two independent actuators to the decoupled swing and lift outputs of a leg,and each leg can produce the closed trajectories in the sagittal plane necessary for robot motion.Moreover,the kinematics of the transmission are analyzed,and the parameters of the flexure hinges are designed based on geometrical constraints and yield conditions.The hip joints,legs and exoskeletons are integrated into a five-layer standard laminate for monolithic fabrication which is composed of two layers of carbon fiber,two layers of acrylic adhesive and a polyimide film.The measured output force(15.97 mN)of each leg is enough to carry half of the robot’s weight,which is necessary for the robot to move successfully.It has been proven that the robot can successfully perform forward and turning motions.Compared to the microrobot fabricated with discrete components,the monolithically fabricated microrobot is more capable of maintaining the original direction of locomotion when driven by a forward signal and has a greater speed,whose maximum speed is 25.05 cm/s.