Aquatic organisms, due to soft body structure and high agility, have inspired many biomimetic robots. However, considering the issues of insulation and waterproofing, as well as the driving module of soft materials, their control systems are usually larger and heavier. Therefore, small underwater robots often tethered, i.e., it cannot integrate energy and control systems onto the body, which greatly limited in its working range and activity mode. This paper presents a small untethered bionic manta ray. The robotic fish is driven by dielectric elastomer actuators (DEA), which controls the double wing structure on both sides by the central muscle part to simulate the process of the manta ray’s lateral fins fanning to propel itself forward. And the flexible printed circuit board (FPC) constitutes the body of the fish and is also an independent energy control system. The electronic components are evenly distributed on the double-wing structure of the robotic fish to realize the integration of the energy control system. This circuit system can be powered by a small lithium battery and output a periodic voltage to drive the motion of the robotic fish. The masses of our tethered and untethered fish are 1.9g and 5.1g respectively. The swimming speed of these two types of fish can reach 42.5mm/s and 17.0 mm/s. And this design principle can be extended to the research and design of various flexible devices and soft robots.

Abstract The precise perception of the surrounding environment in traffic scenes is an important part of an intelligent transportation system. The event camera could provide complementary information to traditional frame‐based cameras, such as high dynamic range, and high time resolution, in the perception of traffic targets. To improve the precision and reliability of perception as well as facilitate lots of RGB camera‐based studies introduced to event cameras directly, a refined registration method for event‐based cameras and RGB cameras on the basis of pixel‐level region segmentation is proposed, to provide a fusion method at pixel level. A total of eight sequences and a dataset containing 260 typical traffic scenes are contained in the experiment dataset, both selected from DSEC, a traffic event‐based dataset. The registered event image shows a better spatial consistency with RGB images visually. Compared to the baseline, the evaluation indicators, such as the performance of the contrast, the proportion of overlapping pixels, and average registration accuracy have been improved. In the traffic object segmentation task, the average boundary displacement error of our method has decreased and the max decline value has reached 79.665%, compared to the boundary displacement error between ground truth and baseline. These results indicate prospective applications in the perception of intelligent transportation systems combined with event and RGB cameras. The traffic dataset with pixel‐level semantic annotations will be provided soon.

Lower-limb assisted exoskeletons are widely researched for movement assistance or rehabilitation training. Due to advantages of compliance with human body and lightweight, some cable-driven prototypes have been developed, but most of these can assist only unidirectional movement. In this paper we present an untethered cable-driven ankle exoskeleton that can achieve plantarflexion-dorsiflexion bidirectional motion bilaterally using a pair of single motors. The main weights of the exoskeleton, i.e., the motors, power supplement units, and control units, were placed close to the proximity of the human body, i.e., the waist, to reduce the redundant rotation inertia which would apply on the wearer’s leg. A cable force transmission system based on gear-pulley assemblies was designed to transfer the power from the motor to the end-effector effectively. A cable self-tension device on the power output unit was designed to tension the cable during walking. The gait detection system based on a foot pressure sensor and an inertial measurement unit (IMU) could identify the gait cycle and gait states efficiently. To validate the power output performance of the exoskeleton, a torque tracking experiment was conducted. When the subject was wearing the exoskeleton with power on, the muscle activity of the soleus was reduced by 5.2% compared to the state without wearing the exoskeleton. This preliminarily verifies the positive assistance effect of our exoskeleton. The study in this paper demonstrates the promising application of a lightweight cable-driven exoskeleton on human motion augmentation or rehabilitation.