Shape memory alloy (SMA) wire-based soft actuators have had their performance limited by the small stroke of the SMA wire embedded within the polymeric matrix. This intrinsically links the bending angle and bending force in a way that made SMA-based soft grippers have relatively poor performance versus other types of soft actuators. In this work, the use of free-sliding SMA wires as tendons for soft actuation is presented that enables large increases in the bending angle and bending force of the actuator by decoupling the length of the matrix and the length of the SMA wires while also allowing for the compact packaging of the driving SMA wires. Bending angles of 400° and tip forces of 0.89 N were achieved by the actuators in this work using a tendon length up to 350 mm. The tendons were integrated as a compact module using bearings that enables the actuator to easily be implemented in various soft gripper configurations. Three fingers were used either in an antagonistic configuration or in a triangular configuration and the gripper was shown to be capable of gripping a wide range of objects weighing up to 1.5 kg and was easily installed on a robotic arm. The maximum pulling force of the gripper was measured to be 30 N.

A novel linear actuator called origami-based vacuum pneumatic artificial muscle (OV-PAM) is proposed in this study that can produce large forces (>400 N) with a contraction ratio >90% of the active length of the actuator. Moreover, some of the designs presented in this article can lift large loads with large contraction ratios at extremely low vacuum pressure (≈10 kPa). This actuator consists of a sealed origami film chamber connecting a polygonal top and bottom plate with evenly spaced transversal reinforcements that prevent the chamber from contracting laterally at certain points of the actuator under vacuum pressure. As vacuum pressure is applied, both a tension force in the walls and a vertical force on the bottom plate of the actuator generate a large contractile force, and the force on the bottom plate can produce a consistent force throughout the entire motion. A quasistatic analytical model was developed that can accurately predict the behavior of the actuator and that can be used for actuator design. OV-PAMs are lightweight, have large contractile forces throughout their entire motion and large contraction ratios. It can also produce large forces at low pressures with large cross-sectional areas. Their versatility could make them well suited for a wide range of applications. They could take us closer to a future where robots can cooperate with humans to shape a better future.

The robotic gripper is an essential component for handling, manipulating, and transporting objects. However, the parallel rigid gripper, which is one of the most widely used grippers in robotics, has limitations in handling fragile objects with a proper gripping force. We present a shape-adaptive universal soft gripper that can grip complex-shaped fragile objects with a high holding force. The shape-adaptive skin of the gripper has extremely low stiffness ( ~ 46 kPa), even lower than that of tofu ( ~ 57 kPa); hence, it can inherently prevent damage to the object. In addition, only the area pressed by the object is selectively deformed, so the contact surface of the gripper can be deformed to match the target object contour. A stiffness transition in the gripper from a soft to hard state follows to achieve effective holding of the object, not just weak object hanging as the previous soft gripper. These characteristics are enabled by a sheet-shaped shape retention layer, a honeycomb-shaped soft supporting layer, and a four-sided wall structure to increase shear modulus. We present applications to show the performance of the gripper, including gripping tofu, preparing a cocktail with a squeezed lemon, and whole chicken soup.

Soft pneumatic robotic grippers can be used to conduct a wide range of tasks in extreme environments as they are generally free of conductive or magnetic components. But the sensorization of these grippers can potentially make them unsuitable for such environments and lower their performance through the introduction of electronic components or conductive materials into their structure. This work introduces the design of a sensorized soft pneumatic gripper using hybrid optical fibers making use of rigid and hard segments to measure the bending deformation and the contact force at specific segments of the finger. Using rigid optical fibers, which has low optical loss, for optical signal transmission allows to place all electronic components outside and away from the gripper ensuring the structure of the gripper and its nearby components are non-conductive and non-magnetic. The utilization of rigid reinforcements on the soft pneumatic actuator also helps maintain the performance of the actuator close to existing non-sensorized soft pneumatic actuators. This sensorized actuator is then used in a proprioceptive soft robotic gripper capable of controlling its grasping force.