Artificial muscles embody human aspirations for engineering lifelike robotic movements. This paper introduces an architecture for Inflatable Fluid-Driven Origami-Inspired Artificial Muscles (IN-FOAMs). A typical IN-FOAM consists of an inflatable skeleton enclosed within an outer skin, which can be driven using a combination of positive and negative pressures (e.g., compressed air and vacuum). IN-FOAMs are manufactured using low-cost heat-sealable sheet materials through heat-pressing and heat-sealing processes. Thus, they can be ultra-thin when not actuated, making them flexible, lightweight, and portable. The skeleton patterns are programmable, enabling a variety of motions, including contracting, bending, twisting, and rotating, based on specific skeleton designs. We conducted comprehensive experimental, theoretical, and numerical studies to investigate IN-FOAM's basic mechanical behavior and properties. The results show that IN-FOAM's output force and contraction can be tuned through multiple operation modes with the applied hybrid positive-negative pressure. Additionally, we propose multilayer skeleton structures to enhance the contraction ratio further, and we demonstrate a multi-channel skeleton approach that allows the integration of multiple motion modes into a single IN-FOAM. These findings indicate that IN-FOAMs hold great potential for future applications in flexible wearable devices and compact soft robotic systems.

Origami designs and structures have been widely used in many fields, such as morphing structures, robotics, and metamaterials. However, the design and fabrication of origami structures rely on human experiences and skills, which are both time and labor-consuming. In this paper, we present a rapid design and fabrication method for string-driven origami structures and robots. We developed an origami design software to generate desired crease patterns based on analytical models and Evolution Strategies (ES). Additionally, the software can automatically produce 3D models of origami designs. We then used a dual-material 3D printer to fabricate those wrapping-based origami structures with the required mechanical properties. We utilized Twisted String Actuators (TSAs) to fold the target 3D structures from flat plates. To demonstrate the capability of these techniques, we built and tested an origami crawling robot and an origami robotic arm using 3D-printed origami structures driven by TSAs.

The goal of achieving `universal grasping' where many objects can be handled with minimal control input is the focus of much research due to potential high impact applications ranging from grocery packing to recycling. However, many of the grippers developed suffer from limited sensing capabilities which can prevent handing of both heavy bulky items and also lightweight delicate objects which require fine control when grasping. Sensorizing such grippers is often challenging due to the highly deformable surfaces. We propose a novel sensing approach which uses highly flexible latex bladders. By measuring changes in the air pressure of the bladders, normal force and longitudinal strain can be measured. These sensors have been integrated into a `Magic Ball' origami gripper to provide both tactile and proprioceptive sensing. The sensors show reasonable sensitivity and repeatability, are durable and low-cost, and can be easily integrated into the gripper without affecting performance. When the sensors are used for classification, they enabled identification of 10 objects with over 90% accuracy, and also allow failure to be detected through slippage detection. A control algorithm has been developed which uses the sensor feedback to extend the capabilities of the gripper to include both delicate and strong grasping. It is shown that this closed loop controller enables delicate grasping of potato chips; 80% of those tested were grasped without damage.

Soft robotics has yielded numerous examples of soft grippers that utilize compliance to achieve impressive grasping performances with great simplicity, adaptability, and robustness. Designing soft grippers with substantial grasping strength while remaining compliant and gentle is one of the most important challenges in this field. In this paper, we present a light-weight, vacuum-driven soft robotic gripper made of an origami “magic-ball” and a flexible thin membrane. We also describe the design and fabrication method to rapidly manufacture the gripper with different combinations of low-cost materials for diverse applications. Grasping experiments demonstrate that our gripper can lift a large variety of objects, including delicate foods, heavy bottles, and other miscellaneous items. The grasp force on 3D-printed objects is also characterized through mechanical load tests. The results reveal that our soft gripper can produce significant grasp force on various shapes using negative pneumatic pressure (vacuum). This new gripper holds the potential for many practical applications that require safe, strong, and simple grasping.

Autonomous control of magnetically-actuated miniature robots enables greater versatility and complexity in function but has so far been a challenge to implement. In this paper, we present closed-loop position feedback control of a miniature origami robot utilizing its integrated magnet and an array of Hall effect sensors, enabling the robot's actuation, detection, and locomotion to be initiated from outside its body. An array of 33 Hall effect sensors arranged in repeated triangles cover a range of 60 mm by 75 mm, enabling position detection of the robot with average error of 0.995±0.520 mm. The robot's speed response to applied magnetic field was characterized, and a controller was designed to actuate the robot dependably. We demonstrate autonomous movement of the robot along preplanned paths and the viability of magnetic detection and actuation.

Developing miniature robots that can carry out versatile clinical procedures inside the body under the remote instructions of medical professionals has been a long time challenge. In this paper, we present origami-based robots that can be ingested into the stomach, locomote to a desired location, patch a wound, remove a foreign body, deliver drugs, and biodegrade. We designed and fabricated composite material sheets for a biocompatible and biodegradable robot that can be encapsulated in ice for delivery through the esophagus, embed a drug layer that is passively released to a wounded area, and be remotely controlled to carry out underwater maneuvers specific to the tasks using magnetic fields. The performances of the robots are demonstrated in a simulated physical environment consisting of an esophagus and stomach with properties similar to the biological organs.

Impact protection and vibration isolation are an important component of the mobile robot designer's toolkit; however, current damping materials are available only in bulk or molded form, requiring manual fabrication steps and restricting material property control. In this paper we demonstrate a new method for 3D printing viscoelastic materials with specified material properties. This method allows arbitrary net-shape material geometries to be rapidly fabricated and enables continuously varying material properties throughout the finished part. This new ability allows robot designers to tailor the properties of viscoelastic damping materials in order to reduce impact forces and isolate vibrations. We present a case study for using this material to create jumping robots with programmed levels of bouncing.

Soft-bodied robots are designed to work in the physical world with a high compliance, while most of them lack in highly dynamic motion. In this paper, we present a soft-bodied jumping robot, which leverages its body's elasticity to achieve a highly dynamic passive bouncing motion after an active jumping motion. This robot has a cubic shape. It is covered by silicone foam, and each of its six faces has an opening to allow for jumping actuation. By winding up and releasing an elastic strip, the robot can jump in two directions at any orientation. We present the design, and fabrication process, and experimental results. By comparing this robot with a rigid version of the robot, we show that this soft-bodied robot can use a single jump to travel longer forward than its rigid counterpart.

This paper explores the use of a deformable octahedron robot as an alternative for the autonomous exploration of complex confined spaces, voids and tunneling structures. Current robotic platforms lack the capabilities for adapting their shape when moving through intricate sections of cavities. We discuss the geometrical and dynamical properties of a deformable octahedral platform. We use real and simulated robots to test and synthesize locomotion controllers that allow our robots to travel along different portions of a tunneling test bed. Evolutionary methods allow us to automatically produce controllers for in-pipe motion. We demonstrate the capabilities of peristaltic locomotion, different modes of deformation and volumetric adaptation. An evaluation of motion capabilities inside pipe elbows and branches is performed. Our results suggest that this type of deformable robot has a potential for travelling along confined spaces.

In this paper, we validate whether the network modularity can emerge, and the evolution performance can be improved by varying the environment or evolution process under a more freeform artificial evolution. Previous studies have demonstrated that the modular structure naturally arisen as a response of the variations on environment and selection process, however, since the models they used were relatively simple and with some biasing constraints, the results may lack of generality. In contrast, we evolve more freeform neural networks to address this issue, and an artificial tracer method was employed to quantify the modularity. A series of varying scenarios have been experimented, the results show that the evolution performance have been improved in most cases, however, the modularity never appeared among those scenarios. A further experiment shows that our method has the potentials to produce modular networks but the more advanced methods are still needed to encourage the emergence of modularity on the complex questions.

We present a concept for a modular robot with a quasi-regular polyhedron based on a cuboctahedron element. Lattice-type modular robots can adapt their morphology by reconfiguring to various shapes. While regular polyhedrons provide the bases of many promising 3D lattice elements, few modular robots have shapes with more than six regular faces. The conceptual design and prototypes of cuboctahedron elements are presented in this paper. To account for the various connecting configurations between robotic modules, we propose a directed graph with three parameters to represent the morphology of such a modular robotic system.