Soft robotics最新文献

Previous rolling soft robots have difficulty in balancing the locomotion speed with energy efficiency and have limited terrain adaptability. This work proposes a rolling soft robot driven by local snap-through buckling, which employs the fast response and configuration maintenance of the bistable structure to enhance the locomotion performance of the soft robot. A theory based on bifurcation and the energy principle is established to analyze the rolling mechanism. The influences of loading position and geometric parameters on the rolling performance are investigated and verified experimentally. The soft robot shows good locomotion speed (0.95 body length per second, BL/s) and small energy loss due to the almost unchanged configuration during the rolling process. The soft robot adapts to complex terrains, including a step with the height of 15 mm, a slope with the angle of 18.36°, and a broken bridge with the gap length of 90 mm (0.443 BL). The proposed rolling soft robot not only has good application prospects in land exploration missions and medical applications but also provides inspiration for the development of rolling soft robots.

Fragile fruit uploading and packaging are labor-intensive and time-consuming steps in postharvest industry. With the aging of the global population, it is supposed to develop robotic grasping systems to replace manual labor. However, damage-less grasping of fragile fruit is the key problem in robotization. Inappropriate grasping force will result in damage, early-stage bruise, or slip. Benefits from the advantages of softness and compliance of a pneumatic-driven soft gripper have been widely adopted for agricultural product and food manipulation. Nevertheless, pneumatic gripper is a complex, multivariable, nonlinear, and long time-delay control system, which is difficult to achieve robust closed-loop grasping force control. In this study, we aim to solve this problem and developed a robotic grasping force control system with pneumatic gripper and matrix force sensor. The force distribution condition was explored to tackle the problem in changing of the main contact point. A double closed-loop control method was proposed based on Kalman filter (KF) and proportion integration differentiation controller with dead band. The external and internal control loops were force controller and air pressure of the pump controller, respectively. The double closed-loop controller with dead band achieved robust grasping force control through air pressure. The experimental results validated the effectiveness of the KF method for denoising and the matrix force visualization method for exploring grasping mechanism. Ablation studies were carried out to demonstrate the effectiveness of the multiple grasping force sensing units in matrix form and the dead band in the controller. The maximum steady-state error was 0.07 N. In addition, the generalization performance and the antidisturbance ability of the grasping force control system was also validated. In summary, the problem in closed-loop control of the grasping force for pneumatic gripper has been solved in our study, and the method in this research is potential to be deployed in fruit postharvest industry.

Modular soft robots (MSRs) exhibit greater potential for sophisticated tasks compared with single-module robots. However, the modular structure incurs the complexity of accurate control and necessitates a control strategy specifically for modular robots. In this article, we introduce a data collection strategy tailored for MSR and a bidirectional long short-term memory (biLSTM) configuration controller capable of adapting to varying module numbers. Simulation cable-driven robots and real pneumatic robots have been included in experiments to validate the proposed approaches. Experimental results have demonstrated that MSRs can explore a larger space, thanks to our data collection method, and our controller can be leveraged despite an increase or decrease in module number. By leveraging the biLSTM, we aim to mimic the physical structure of MSRs, allowing the controller to adapt to module number change. Future work may include a planning method that bridges the task, configuration, and actuation spaces. We may also integrate online components into this controller.

Continuum manipulators can improve spatial adaptability and operational flexibility in constrained environments by endowing them with contraction and extension capabilities. There are currently desired requirements to quantify the shape of an extensible continuum manipulator for strengthening its obstacle avoidance capability and end-effector position accuracy. To address these issues, this study proposes a methodology of using silicone rubber strain sensors (SRSS) to estimate the shape of an extensible continuum manipulator. The way is to measure the strain at specific locations on the deformable body of the manipulator, and then reconstruct the shape by integrating the information from all sensors. The slender sensors are fabricated by a rolling process that transforms planar silicone rubber sensors into cylindrical structures. The proprioceptive model relationship between the strain of the sensor and the deformation of the manipulator is established with considering the phenomenon of torsion of the manipulator caused by compression. The physically extensible continuum manipulator equipped with three driving tendons and nine SRSS was designed. Comprehensive evaluations of various motion trajectories indicate that this method can accurately reconstruct the shape of the manipulator, especially under end-effector loads. The experimental results demonstrate that the mean (maximum) absolute position error of the endpoint is 1.61% (3.45%) of the manipulator length.

Robotics is entering our daily lives. The discipline is increasingly crucial in fields such as agriculture, medicine, and rescue operations, impacting our food, health, and planet. At the same time, it is becoming evident that robotic research must embrace and reflect the diversity of human society to address these broad challenges effectively. In recent years, gender inclusivity has received increasing attention, but it still remains a distant goal. In addition, awareness is rising around other dimensions of diversity, including nationality, religion, and politics. Unfortunately, despite the efforts, empirical evidence shows that the field has still a long way to go before achieving a sufficient level of equality, diversity, and inclusion across these spectra. This study focuses on the soft robotics community-a growing and relatively recent subfield-and it outlines the present state of equality and diversity panorama in this discipline. The article argues that its high interdisciplinary and accessibility make it a particularly welcoming branch of robotics. We discuss the elements that make this subdiscipline an example for the broader robotic field. At the same time, we recognize that the field should still improve in several ways and become more inclusive and diverse. We propose concrete actions that we believe will contribute to achieving this goal, and provide metrics to monitor its evolution.

In this study, we propose a fabric muscle based on the Zigzag Shape Memory Alloy (ZSMA) actuator. Soft wearable robots have been gaining attention due to their flexibility and the ability to provide significant power support to the user without hindering their movement and mobility. There has been an increasing focus on the research and development of fabric muscles, which are crucial components of these robots. This article introduces a high-performance fabric muscle utilizing zigzag-shaped shape memory alloy (SMA), ZSMA, a new form of SMA actuator. Through modeling and experimentation of the ZSMA actuator, we identified an optimized actuator design and detailed the fabric muscle fabrication process. The proposed fabric actuator, weighing only 7.5 g, demonstrated the impressive capability to lift a weight of 2 kg with a contraction displacement of 40%. This significant achievement paves the way for future research possibilities in soft wearable robotics.

The octopus has attracted widespread attention owing to its unique underwater movement and its ability to escape with inkjets, which also promoted the development of underwater bionic robots. This study introduces a magnetic octopus robot (MOR) 3D printed with PA6/NdFeB composite material, which has good magnetic responsiveness and rigidity to cope with complex environments. The MOR can roll and rotate through complex terrain and passages because of its eight-claw structure. It also has amphibious locomotion and can pass through narrow gaps of 37.5% of its height by deformation. In addition, the MOR can not only clamp, transport, and release solids but also liquids by adding silicone hollow spheres, which indicates the potential of the MOR to be used in medical applications for transporting solid or liquid drugs. This research will help broaden the application prospects of magnetron robots in the field of medical drug transportation.

Wearable robots, especially those composed of soft materials, are increasingly attracting interest due to their comfort, ease of donning and doffing, and their ability to provide assistance across various applications. In wearable robotics, striking a balance between ensuring low impedance for wearer comfort and providing sufficient assistive force is a notable design challenge. In this study, we propose exploiting impedance variation in accordance with the types of muscle contraction in the human body. Particularly in eccentric muscle contraction, the impedance can help reduce the muscular load, since it exerts force in the same direction as the muscles. To utilize the relation, we proposed a linked-layer jamming mechanism, which adjusts its impedance largely in various directions. This mechanism allows not only a broad variable range of impedance in multiple rotation directions but also directional torque design, even when equipped in human multi-degree-of-freedom (DoF) joints. By constructing a wearable robot prototype equipped with the proposed linked-layer jamming mechanisms, the effectiveness of this impedance-based assistance approach was confirmed through experiments. The findings from this study present new possibilities in wearable robot design, showing that suitably amplified impedance can assist human motion, potentially enhancing task efficiency and lowering injury risk. This work thus offers a new perspective for researchers in the field of wearable robots, demonstrating that impedance, often minimized in existing designs, can be utilized beneficially when properly amplified.

Traditional robots derive their capabilities of movement through rigid structural "links" and discrete actuated "joints." Alternatively, soft robots are composed of flexible materials that permit movement across a continuous range of their body and appendages and thus are not restricted in where they can bend. While trade-offs between material choices may restrain robot functionalities within a narrow spectrum, we argue that bridging the functional gaps between soft and hard robots can be achieved from a hybrid design approach that utilizes both the reconfigurability and the controllability of traditional soft and hard robot paradigms. In this study, we present a hybrid robot with soft inflated "linkages," and rigid internal joints that can be spatially reconfigured. Our method is based on the geometric pinching of an inflatable beam to form mechanical pinch-joints connecting the inflated robot linkages. Such joints are activated and controlled via internal motorized modules that can be relocated for on-demand joint-linkage configurations. We demonstrate two applications that utilize joint reconfigurations: a deployable robot manipulator and a terrestrial crawling robot with tunable gaits.

The somatosensory system is crucial for living beings to survive and thrive in complex environments and to interact with their surroundings. Similarly, rapidly developed soft robots need to be aware of their own posture and detect external stimuli. Bending and force sensing are key for soft machines to achieve embodied intelligence. Here, we present a soft inductive bimodal sensor (SIBS) that uses the strain modulation of magnetic permeability and the eddy-current effect for simultaneous bidirectional bending and force sensing with only two wires. The SIBS is made of a flexible planar coil, a porous ferrite film, and a soft conductive film. By measuring the inductance at two different frequencies, the bending angle and force can be obtained and decoupled. Rigorous experiments revealed that the SIBS can achieve high resolution (0.44° bending and 1.09 mN force), rapid response, excellent repeatability, and high durability. A soft crawling robot embedded with one SIBS can sense its own shape and interact with and respond to external stimuli. Moreover, the SIBS is demonstrated as a wearable human-machine interaction to control a crawling robot via wrist bending and touching. This highlights that the SIBS can be readily implemented in diverse applications for reliable bimodal sensing.