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A military wheel-leg hybrid quadruped robot is developed, which can move by the dynamic driving wheels on the road without being damaged at high speed, and can walk by stepping alternately in the ruins with its mechanical legs, and can skate on a flat road by the wheels without dynamic driving.The robot can walk at the maximum speed with the minimum energy consumption. A new type of meta-morphic mechanical leg based on the 3-PUPS parallel mechanism is proposed, and its kinematic analysis is done. The effects of dimension parameters of 3-PUPS mechanism on its kinematic and static evaluation indexes are analyzed by defining performance evaluation indexes. A set of the structural parameters of mechanical leg is selected, and an experimental prototype of mechanical leg is developed. A general mechanism model of wheel-leg hybrid quadruped robot is established, and the relationship among robot’s parameters and its kinematic and static evaluation indexes is revealed. A set of structural parameters of wheel-leg hybrid quadruped robot is selected,and the overall design of wheel-leg hybrid quadruped robot is completed. The pose of mechanical leg experimental prototype is measured using a special robot calibration system. Experimental results show that the maximum error of mechanical leg motion platform along x axis is 0.041 mm, the maximum error along y axis is 0.040 mm, the maximum error along z axis is 0.040 mm, the maximum error of the attitude angle around z axis is 0.041°, the maximum error of attitude angle around y axis is 0.043°, and the maximum error of attitude angle around x axis is 0.045°. The experimental prototype of mechanical leg meets the design requirements. [ABSTRACT FROM AUTHOR]

A new type of wheel-leg hybrid quadruped robot is proposed, which has four 6-DOF mechanical legs based on 3-UPS parallel mechanism. The dynamics of mechanical legs are modeled, and their driving parameters are predicted. The vector chain method is used to establish a transfer model of 3-UPS parallel mechanism, and the Jacobian matrix is established. A dynamics model of mechanical legs is established based on the Lagrange equation, and the drive force acted on the mechanism is given. The peak prediction model of servo motors for driving speed and torque is analyzed based on the dynamics model. The calculated result shows that the peak value of rotating speed of driving motor is 19.7 r/s, and the peak value of torque of driving motor is 71 mN·m. A design scheme of mechanical leg and its structure parameters are used to obtain the changes of driving speeds and torques of 6 motors over time. The calculated results show that the peak speed of driving motor is 15.3 r/s, and its peak torque is 48.1 mN·m, which are all less than the predicted limit values. The predicted peak power of servo motors is 77 (W). It proves that the dynamic analysis and the peak prediction model of driving parameters of the mechanical leg are very reasonable. [ABSTRACT FROM AUTHOR]

With the aid of the VISAR, the velocity histories of rear free surface of the alumina with different thicknesses under plate impact loading were recorded. The failure wave trajectory was obtained from the recompression signals observed in the temporal curves of rear free surface velocity of samples. The results indicate that the generation and propagation mechanisms of failure wave are closely related to the mesoscale failure properties of alumina. The mesostructure properties of tested alumina were studied according to the SEM of alumina samples. Based on these properties, a mesoscopic model of alumina, including alumina grain phase and glassy phase, is established. Further, mesoscale simulations were presented to analyze the mesoscale failure properties of alumina. And the generation and propagation mechanisms of failure waves in shocked alumina were researched at the mesoscale. The results show that the nucleation and growth of rapid in-situ grain boundary microcracks under impact loading give rise to the failure wave phenomenon, and the failure wave propagation may be governed by diffusion processes. [ABSTRACT FROM AUTHOR]