Robotic Pick‐and‐Place Operations in Multifunctional Liquid Crystal Elastomers

Abstract

Pick‐and‐place operations for transporting objects precisely to a target position are a prominent function of (soft‐) robotic systems. Therefore, there is great interest in industry to improve the characteristic gripping, holding, and releasing methods involved in pick‐and‐place operations. Within living organisms such as octopi, nature demonstrates that multiple types of conjointly working actuators are required for flexible pick‐and‐place operations. Herein, a multifunctional soft robotic arm is developed, capable of transporting an object within 3D space. The soft robotic arm consists of two structural actuators (rotating base and lifting unit) and a suction cup‐based gripper. The structural actuator acts as both the load bearing and actuating components of the robotic system. Yet, the gripper is the crucial innovation within the robotic arm. A cephalopod‐limb‐inspired gripper functioning through the reversible flat‐to‐conical deformation of azimuthally aligned liquid crystal elastomer (LCE) films is proposed. The pressure‐generating actuation mechanism of the gripper means that no external device is needed to operate the gripping function. Akin to natural systems, the in‐tandem operation of the actuators in the soft robotic arm allows for multifactored tasks. Yet, the design achieves this through the use of a single material, which is not innate in natural archetypes.

Recent Advances in Electrically Driven Soft Actuators across Dimensional Scales from 2D to 3D

“…[106] The deformation can be stimulated by light, heat, electronic stimuli, and magnetic with corresponding photothermal, electrothermal, and magnetothermal effect. [107][108][109][110] Removing the source of stimulation leads to the release of energy stored as mechanical energy. Combining this property with a proper design of the stimulation source, the actuator will be programmable and even acquire the ability of associative learning.…”

Hot Fingers: Individually Addressable Graphene-Heater Actuated Liquid Crystal Grippers

“…Stimuli-responsive materials have been receiving increased attention, especially for motile devices, biomedical applications including wearables and surgical devices, dynamic surfaces, and materials for personal comfort. − Liquid crystal (LC) actuators based on LC elastomers (LCEs) or LC networks (LCNs) are prime candidate materials for use in soft-touch devices ,− and are promising alternatives to, for example, hydrogels and silicones . LCE/LCN grippers have structures which can bend due to internal disruption of the LC mesogenic order with large deflections at relatively low actuation temperatures, facilitating soft gripping without introducing damage to the object. ,− Nevertheless, soft actuators with control over individual gripper fingers are still in their infancy and often are not optimized: for example, they cannot independently actuate their fingers − or are overly complex in design. , …”

Photochemically Induced Propulsion of a 4D Printed Liquid Crystal Elastomer Biomimetic Swimmer

“…Consequently, the order of LC molecules is disrupted, resulting in macroscopic contraction along the director. [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 ] When the LC system is in air, significant photoinduced heating and deformation can occur quite rapidly. However, if the LC system is in a fluid with higher thermal conductivity than air, the heat generated by the photothermal mechanism is efficiently taken away from the actuator.…”