Preparation And Test Of Microstructure Material With Bionic Surfaces And Design Of Mechanical Gripper

Research and development of new bionic mechanical grippers has drawn the attention of researchers in recent years.Grippers with good performance can be widely applied in the field of health care,industrial production,daily life services,agriculture,astronautics,etc.An accurate grasp,a strong adaptability,a simple control strategy and a low damage to the object can be considered as standards to evaluate the functionality of a mechanical gripper.However,traditional rigid grippers could not meet the standards due to the complicated structures,the lack of compliance,and damages to objects due to the rigid contacts.Soft grippers consisting of pneumatic components such as air pumps and air extractors inspired by living creatures such as octopus have high energy consumptions,low energy efficiencies,poor portabilities,and are not easy to fabricate with high cost.Therefore,inspired by the filamentous mastoid structures of typical animal tongues,this paper presents a bioinspired micro-patterned surfaces,based on which designs a novel bioinspired mechanical gripper is designed.Aiming to improve the flexibility and adaptability of the grasp,reduce the damage to the object,and increase the grasping efficiency,we conducted the research as follows:(1)Based on the morphology of filamentous mastoid structures on the surface of tongues of typical animals,a microscale array with wedge-shaped microstructures is designed,and a corresponding mold is fabricated with microscal 3D printing technology;A transition mold made of PDMS matrix helped transfer the micro-structure,to the ecoflex00-30 silicone rubber matrix,verified by a optic microscope.(2)A contact force testing platform is established,Adhesive forces in the normal and tangential directions of specimens made of ecoflex00-30 matrix with/without microstructures are tested and analyzed.Results show that the microstructures can enhance the adhesion in the normal and tangential directions,thus can be applied to the prototype of the mechanical gripper.(3)A novel mechanical gripper is designed which is actuated by servomotors.Rigid parts of the mechanical gripper are fabricated using 3D–printing.assembled into a gripper with the control unit;The micro-patterned surface is bonded with the gripper by pouring a layer of the liquid ecoflex 00-30 on the gripper’s inner surface.(4)Friction forces of a conventional and a bioinspired one are tested via MTS,and the bioinspired surface is proved to enhance the gripping capability;The adaptability and the reliability of the bioinspired mechanical gripper are verified by grasping tests for common objects in daily life,which are different in sizes and shapes;The adhesion and the grasping ability of the bioinspired mechanical gripper are verified in experiments as well as the protective effect on objects;In the maximum load experiment,the load capacity of the bioinspired mechanical gripper is tested.(5)Performances of an ordinary mechanical gripper and the proposed one are analyzed and compared via the following simulation covering three main aspects.First,gripping reaction forces when gripping the same object are measured and compared;Second,amplitudes with sinusoidal acceleration load applied of the same vibration frequency are recorded and analyzed;Third,amplitudes with identical impact energy applied are recorded and analyzed.Via these simulations,the compliance,adaptability,and reliability of the gripper is verified.