Electroadhesion (EA), as an electrostatically driven, controllable adhesion technology, has unique attributes such as low noise, robust adaptability, and energy efficiency. However, its adhesion pressure is still low (0.1~10kPa) which may significantly limit its applications. This paper presents an innovative electroadhesion pad embedded with liquid and solid dielectrics. The experiments demonstrate that this liquid-solid electroadhesion pad (LSEAP) is capable of much larger adhesion pressure, compared to the traditional solid electroadhesion pad (SEAP). On one hand, the LSEAP can increase the dielectric contact with the substrate. On the other hand, the actuator can increase its dielectric strength. We also explore the application of this actuator to perching of a commercial Unmanned Aerial Vehicle (UAV), in order to promote the UAV's sustainable flight. Notably, the untethered LSEAP system, with an adhesion area as small as 4 cm2and a self-weight as light as 8.7 g, can support an UAV of 249.7 g for stable adhesion on various surfaces. The adhesion pressure generated by our LSEAD can be 32.2kPa, significantly larger than those reported in the literature. The weight ratio of the UAV to the LSEAP system is 14.6, more than double those in previous studies. The integration of this EA system markedly prolongs the operational duration of UAVs, rendering them suitable for sustainable surveillance and reconnaissance missions. This LSEAP also marks a pivotal advancement towards adhesion-based applications such as grippers and wall-climbing robots.

Various variable stiffness mechanisms have been developed to bestow new capabilities for the robotics community by changing the mechanical behaviors of robots. However, variable stiffness is limited in actuation, response speed, stiffness ratio, and, most importantly, modeling. This article proposes hybrid actuated laminar jamming to outperform individual actuated variable stiffness mechanisms. An analytical model for multilayer laminar jamming that accurately characterizes mechanical behaviors in experiments is first built. Comprehensive parametrical analysis based on this model serves as design guidelines for performance improvements of laminar jamming. Feedforward control further proves the validity of the proposed model and exhibits good controllability, showing response speed as fast as 5 ms. The synergy between electroadhesion and vacuum actuation significantly enhances overall performance, resulting in far greater effects than individual contributions. For instance, the proposed device generates a high stiffness that is almost impossible for individual vacuum or electroadhesion. Moreover, vacuuming increases 23% of the breakdown voltage, which leads to a larger electroadhesion force and, hence, a higher stiffness.

Miniature soft robots present great potential in delicate manipulations due to their gentle force, complaint structures, and flexible motions. Easy control and fast response make pneumatic actuation a prevalent method for driving soft robotics. In addition, sequential motions are also crucial for enhancing the grasping and moving abilities of soft robots. How-ever, existing miniature pneumatic soft robots are limited to one-dimensional geometries and simple motions due to the difficulties in designing and fabricating intricate small airways in miniature pneumatic soft robots, which restricts them from more versatile deformations. Here, we employ intricate monolithic microchannels embedded into miniature soft robots' mon-olithic bodies for sequential motions. After verifying the effects of the channel diameter, strain-limiting layer, and elastic modulus of the robot's body on the bending behaviors of the ID soft robots, we fabricated a soft flower robot capable of sequential and simultaneous 3D-to-3D shape morphing through five individual microchannels and a soft carnivorous plant robot containing 2D interconnected microchannels capable of sequential enclosed grasping through a single inlet.

Haptic gloves allow the players to feel the virtual world more realistically by providing force feedback. At present, haptic gloves are mainly driven by conventional motors, and for them, being lightweight, low cost, low in power consumption, and intrinsically safe to operators are challenging. Here, we designed a haptic glove (So-EAGlove) integrating a flexible electrostatic adhesive brake to resist human fingers with a tunable braking force and render a softness sensation. This glove weighs only 51 g, but is capable of simulating objects in a large range of Young's modulus from 540 Pa to 5.4 MPa. The electrostatic adhesive brake costs only approximately 2.43 mW during operation, i.e., more than three days powered by a small button battery. We built a feedforward control model and evaluated its performance. Experimental results show that this glove can generate an accurate force to follow the force-displacement profile of the corresponding real objects. The error is less than 7%, barely noticeable by the subjects. The subjective tests also demonstrate that little statistical difference exists between the real objects and the virtual objects for the subjects.

Planar and flexible climbing robots suffer from buckling while climbing on a vertical surface. This paper analyzes two different modes: one-end free buckling and two-ends fixed buckling. As an example for buckling analyses, the paper focuses on an electrostatic climbing robot that features thin body. As the body of the robot has only 2.5 mm of thickness, it is more prone to buckling than any other flexible robots, making it the best example for the buckling problem. Based on the analyses, the paper proposes a buckling-free control strategy for the electrostatic robots. The proposed strategy guarantees the force balance between adhesive force and weight force, as well as the elastic stability of the robot. To implement the strategy, the paper investigates the available region of the proper forces and optimal parameters on the prototype robot. A prototype of climbing robot was developed to verify the analyses and solutions, weighing merely 29 g (excluding battery and control circuits). It successfully climbed up a vertical wall without buckling, carrying the payload of 0.4 N.

This paper presents a new kind of climbing robots whose locomotion and adhesion are both realized by electrostatic force. Two crawler-type robots were prototyped. For both of the prototypes, high-power electrostatic film motors are installed. The slider of the electrostatic motor works as a crawling belt as well as an electrode for electroadhesion. The first prototype that has a rigid mechanical structure is light in weight (49 g) and thin in thickness (14 mm). It can climb on a vertical aluminum board with a speed up to 104 mm/s and horizontally pull a payload of about 3.2 N. The other prototype is equipped with a flexible mechanical structure that consists of a series of passive joints. By smoothly transitioning from a horizontal floor up to a slope, the robot demonstrated its capability to comply with complicated surfaces.