A multi-posture 3D printed actuator composed of VT-type bidirectional deflection fishbone-like modules based on shape memory alloy wires

Abstract

In this paper, a multi-posture actuator (MPA) composed of VT-type bidirectional deflection fishbone-like modules (VBFM) based on shape memory alloy (SMA) wires is proposed for realizing multi-posture deformation control. Through sizing of the VT-type structure and the arrangement of VBFM in series, it is possible to realize the actuator design meeting specific deformation requirements. The thermo mechanical coupling analysis model b- ased on kinematics, dynamics, thermodynamics and SMA models is established to study the VBFM deflection angle and multi-posture performance of the MPA. The experimental and numerical results show that the MPA can achieve the target postures and the maximum deflection angle of the single VBFM in one direction can reach about 1.8°. In addition, the load actuation performance of 1-VBFM and MPA is investigated, and the results show that the actuated deflection angle increases with the input electrical power within its effective range and decreases with the external load. This study lays the foundation for the applications of lightweight modular MPAs in robotics, aerospace, vehicle engineering, etc.

A fast actuated soft gripper based on shape memory alloy wires

“…where x A , x te and x co correspond to x i in equation ( 16), p v1v2 is the macroscopic transition probability parameter of the transition rate from stage v 1 to stage v 2 , v 1 v 2 represents coA (co to A phase transition), Aco (A to co phase transition), Ate (A to te phase transition) and teA (te to A phase transition), respectively. By adding energy balance relationships to dynamic ordinary differential equations, latent heat can be introduced into the macroscopic system to calculate the time derivative of temperature as follow [50]:…”

A novel dual-stage shape memory alloy actuated gripper

“…The DAG specimen using polylactic acid (PLA-1.75 mm) material is printed by a 3D printer Infinity X2, as shown in Figure 6 1 and 2. See the reference (Simone et al, 2019;Fumagalli et al, 2009;Li et al, 2022aLi et al, , 2022b for more details on material parameters. It should be noted that the SMA wire needs to be prestretched during installation to balance the SMA wire, structure and spring in the DAG to its initial state.…”

“…To make dexterous grippers, actuation technologies are developed in conjunction with different smart materials, such as piezoelectric actuators (Lyu and Xu, 2021; Li et al , 2022a, 2022b; Gao et al , 2020), dielectric elastomer actuators (DEA) (Liu et al , 2020; Pourazadi et al , 2019; O Halloran et al , 2008; Prechtl et al , 2021; Kunze et al , 2021) and shape memory alloy (SMA) actuators (Wang and Ahn, 2017; Wang et al , 2020; Lu et al , 2019; Nespoli et al , 2010; Stroud and Hartl, 2020). In these methods, the relatively small actuation stroke of piezoelectric actuators limits its application in mechanical grippers (Chen et al , 2021; Zhang et al , 2020a, 2020b).…”