Gait Regulation of a Bionic Quadruped Robot with Antiparallelogram Leg Based on CPG Oscillator

In order to shorten the research and development cycle of quadruped robot, it is significant to solve the problem of single leg weight-bearing and obtain a smooth gait switching. Firstly, a leg structure with an antiparallelogram is proposed, which greatly enhances the strength and stiffness of the leg in this paper. Secondly, the Simulink-ADAMS cosimulation platform is built and the improved Hopf oscillator is used in the control of robot. This control mode based on CPG realizes the walk and trot gait of quadruped robot. Thirdly, in order to solve the problems of breakpoints, phase-locked, and stopping of gait curve in the process of gait switching by directly replacing the gait matrix, the functional relationship between the right hind leg and duty cycle is introduced to realize the smooth transition of gait curve. The simulation results show that the proposed algorithm can achieve a smooth gait transformation within 4–6 second, which preliminarily proves the feasibility of the algorithm. Finally, the experimental platform is built and the control algorithm is written into the controller to realize the specific gait of the robot, which proves the effectiveness of the proposed method

The Impact of Process Conditions on Surge Current Capability of 1.2 kV SiC JBS and MPS Diodes

This paper demonstrated the impact of process conditions on the surge current capability of 1.2 kV SiC junction barrier Schottky diode (JBS) and merged PiN Schottky diode (MPS). The influence of ohmic contact and defect density produced by implantation was studied in the simulation. The device fabricated with high temperature implantation had less defect density in the implant region compared with room temperature implantation, which contributed to higher hole injection in surge current mode and 20% surge capability improvement. In addition, with lower P+ ohmic contact resistance, the device had higher surge capability. When compared to device fabrication with a single Schottky metal layer in the device active area, adding additional P+ ohmic contact on top of the P+ regions in the device active area resulted in the pn junctions sharing a greater portion of surge current, and improved the devices’ surge capability by ~10%

The Impact of Process Conditions on Surge Current Capability of 1.2 kV SiC JBS and MPS Diodes

This paper demonstrated the impact of process conditions on the surge current capability of 1.2 kV SiC junction barrier Schottky diode (JBS) and merged PiN Schottky diode (MPS). The influence of ohmic contact and defect density produced by implantation was studied in the simulation. The device fabricated with high temperature implantation had less defect density in the implant region compared with room temperature implantation, which contributed to higher hole injection in surge current mode and 20% surge capability improvement. In addition, with lower P+ ohmic contact resistance, the device had higher surge capability. When compared to device fabrication with a single Schottky metal layer in the device active area, adding additional P+ ohmic contact on top of the P+ regions in the device active area resulted in the pn junctions sharing a greater portion of surge current, and improved the devices’ surge capability by ~10%

High-strength 91 W-6Ni-2Co-1Fe tungsten heavy alloys prepared by laser melting deposition using granulated powder

This study introduces a new approach for fabricating high-strength 91 W-6Ni-2Co-1Fe tungsten heavy alloys (WHAs) using laser melting deposition (LMD) with a specially formulated granulated powder, characterized by near-spherical particles and a dense structure with fine W grains (2.6 μm). Thin plate samples were prepared using laser powers from 500 W to 900 W, revealing increased density at higher laser power, while the W grain size remains relatively stable. A near-fully dense sample (99% density) with the finest W grain size of 2.8 μm is obtained at a laser power of 900 W, while the highest hardness of 482 HV is achieved at 700 W. The contributions of the high cooling rate of LMD, the Co addition, as well as the use of fine-grained granulated powder to enhance the high strength are discussed. These findings offer significant insights into optimizing WHA fabrication using LMD, highlighting its potential in advanced materials engineerin