Monitoring the state of contact is essential for robotic devices, especially grippers that implement geckoinspired adhesives where intimate contact is crucial for a firm attachment. However, due to the lack of deformable sensors, few have demonstrated tactile sensing for gecko grippers. We present Viko, an adaptive gecko gripper that utilizes vision-based tactile sensors to monitor contact state. The sensor provides high-resolution real-time measurements of contact area and shear force. Moreover, the sensor is adaptive, low-cost, and compact. We integrated gecko-inspired adhesives into the sensor surface without impeding its adaptiveness and performance. Using a robotic arm, we evaluate the performance of the gripper by a series of grasping test. The gripper has a maximum payload of 8N even at a low fingertip pitch angle of 30°. We also showcase the gripper’s ability to adjust fingertip pose for better contact using sensor feedback. Further, everyday object picking is presented as a demonstration of the gripper’s adaptiveness.

The widespread use of fluidic actuation for soft robots creates a high demand for soft pumps and compressors. However, current off-the-shelf pumps are usually rigid, noisy, and cumbersome. As a result, it is hard to integrate most commercial pumps into soft robotic systems, which restricts the autonomy and portability of soft robots. This paper presents the novel design of a soft pump based on bellow structure and super-coiled polymer (SCP) artificial muscles. The pump is flexible, lightweight, modular, scalable, quiet, and low cost. The pumping mechanism and fabrication process of the proposed soft pump is demonstrated. A pump prototype is fabricated to verify the proposed design and characterize its performance. From the characterization results, the pump can reach an output flow rate of up to 54 ml/min and delivers pressure up to 2.63 kPa. The pump has potential applications in untethered soft robots and wearable devices.

This article describes an innovative design of variable stiffness soft actuator, which can potentially be utilized for manipulation and locomotion of soft robots. The new actuator is a combination of two types of actuations: soft pneumatic actuation and muscle-like supercoiled polymer (SCP) actuation. Soft pneumatic actuator has two roles: first is to generate bending motions and second is to increase the stiffness of the whole actuator together with SCP artificial muscles. SCP artificial muscles are exploited to generate pre-load to resist the whole actuator from (excessive) deformation when external load is applied. These two types of actuations are arranged antagonistically to realize stiffness tuning of the whole actuator. At a given bending position, stiffness of the actuator could be tuned by controlling the pressure inside the air chamber and the tension on the SCP artificial muscles. In experimental section, tests are conducted to characterize the applied SCP artificial muscles before they are applied to the proposed actuator. Afterwards, tests of proposed actuator are performed to examine its variable stiffness capability. From experimental results, the proposed actuator can achieve 3.47 times stiffness variation ratio from 0.0312 N/mm(40kPa air pressure and no SCP actuation) to 0.1083 N/mm(82kPa air pressure and SCP actuation at 0.143 W/cm) at the same position (bending angle of 56 degree). This study exhibits the potential of applying SCP artificial muscles to promote the performance of soft robots.