An ornithopter hovers, darts, turns rapidly, and pulls up from a dive by blending paraglider, airplane, and helicopter characteristics.

The traditional single electromechanical conversion energy harvester can collect energy only in a single vibration direction. Moreover, it requires high environmental vibration frequency, and its output power is low. To solve these problems, a cross-shaped magnetically coupled piezoelectric–electromagnetic hybrid harvester is proposed. The harvester comprised a ring-shaped support frame, a piezoelectric generation structure, and an electromagnetic generation structure. The harvester could simultaneously generate energy piezoelectrically and electrically, in addition, it could generate electricity efficiently at a lower environmental vibration, and it can collect the energy in two vibration directions simultaneously. To verify the effectiveness of the device, we set up a vibration experiment system and conducted comparative experiments about non-magnetically coupled piezoelectric, magnetically coupled piezoelectric, and magnetically coupled piezoelectric–electromagnetic hybrid energy harvesters. The experimental results showed that the output power of the magnetically coupled piezoelectric–electromagnetic hybrid energy harvester was 2.13 mW for the piezoelectric structure and 1.76 mW for the electromagnetic structure under the vibration of single-direction resonant frequency. The total hybrid output power was 3.89 mW. The hybrid harvester could collect vibration energy parallel to the ring in any direction. Furthermore, compared with the non-magnetically coupled piezoelectric energy harvester and the magnetically coupled piezoelectric energy harvester, the output power was increased by 141.6% and 55.6%, respectively.

Currently, common vibration energy harvesters can only capture vibration energy in a unidirectional or fixed plane, posing issues such as high collection frequency, limited frequency range, and low output power. This paper proposes a multi-directional broadband piezoelectric-electromagnetic-magnetic coupling composite vibration energy harvester. It achieves three-directional energy harvesting while broadening the harvesting frequency and having a higher power density compared to current state-of-the-art research. Comprising a piezoelectric system and an electromagnetic system, the harvester leverages theoretical analysis to design the piezoelectric cantilever beam with a branching structure, enhancing its broad frequency characteristics. In addition, the magnetic coupling effect is added to the device so that the cantilever beam in three directions can work when the device receives unidirectional vibration excitation. Building on theoretical analysis, the COMSOL 5.6 software is utilized to conduct simulation analysis and optimize the size of the designed piezoelectric cantilever beam structure. This process validates theoretical analysis accuracy and improves energy capture capability. To confirm device viability and simulation accuracy, a physical model is fabricated, and vibration tests are executed. The energy harvester generates two peaks (10 Hz, 27 Hz) when vibration excitation is applied, which effectively broadens the collection frequency. Under the vibration frequency excitation in the X and Y directions, the total composite output power of the multidirectional broadband piezoelectric-electromagnetic-magnetic coupling composite vibration energy harvester is 17.72 mW and 30.22 mW, and the power density can reach 32.85 mW·cm⁻³, which significantly strengthened the captured energy efficiency of the energy harvester compared with the energy harvester without magnetic coupling, with the total composite output power increased by 352.0% and 165.8%, respectively; under the excitation of the Z-direction vibration frequency, the total composite output power was 42.42 mW and 44.80 mW, and the power density could reach 48.70 mW·cm⁻³.

In nature, birds can freely observe and rest on the surface of objects such as tree branches, mainly due to their flexible claws, thus this paper is inspired by bird perching and shows two imitation bird claw perching grasping mechanisms in the shape of “three in front and one at the back”. One is articulated, the other is resilient, the difference being that the former has a pin-articulated claw structure and uses a double fishing line to perform the grasping and resetting action, while the latter uses a resilient linking piece, a single fishing line and resilient linking piece to perform the grasping and resetting action. To verify the grasping effect, experiments were designed to grasp objects of different shapes and maximum grasping weight load. The results show that the two types of perching grasping mechanism can reach a large degree of toe bending, have good passive bending deformation ability, can grasp different types of objects, including the articulated type has a stronger deformation ability, and can grasp branches with a diameter in the range of 12.5–55.8 mm. The elastic reset type is smoother than the articulated type toe bending curve, and the maximum graspable object weight is about three times the overall weight of the grasping mechanism. The maximum gripping weight is about three times the overall weight of the gripping mechanism and the load capacity is about two times that of the articulated type.

It is well known that a multi-axle wheeled robot possesses larger load capability and also higher drive performance. However, its steering flexibility is degraded due to the large number of wheels. In order to solve this problem, in this article, we proposed three control schemes based on the center of rotation or the steering angles of both the first- and last-axle wheels. To release these control schemes, steering mode selection and also the left wheel’s steering angle in a specific axle are added approaching a practical application. Thereafter, the remaining wheels’ steering angles can be calculated with the Ackerman steering theorem. In order to verify the control effects, a five-axle all-wheel-steering wheeled robot has been developed with the Bluetooth wireless monitor system. Based on the newly designed robot, validation experiments are carried out, such as lateral movement, situ rotation, and multi-mode steering within a narrow space. The results indicate that the proposed design in this article can ensure a more flexible and faster movement within a narrow space. It shows large potential in obstacle avoidance compared with the conventional partial-wheel steering mode.