Deformation Forecasting of Huangtupo Riverside Landslide in the Case of Frequent Microseisms

Ever since the impoundment of Three Gorges Reservoir（TGR）, the seismicity in head region of TGR has increased significantly. Coupled with wide fluctuation of water level each year, it becomes more important to study the deformation forecasting of landslides beside TGR. As a famous active landslide beside TGR, Huangtupo riverside landslide is selected for a case study. Based on long term water level fluctuation and seismic monitoring, three typical adverse conditions are determined. With the established 3D numerical landslide model, seepage-dynamic coupling calculation is conducted under the seismic intensity of V degree. Results are as follows： 1. the dynamic water pressure formed by water level fluctuation will intensify the deformation of landslide; 2. under seismic load, the dynamic hysteresis is significant in defective geological bodies, such as weak layer and slip zone soil, because of much higher damping ratios, the seismic accelerate would be amplified in these elements; 3. microseisms are not intense enough to cause the landslide instability suddenly, but long term deformation accumulation effect of landslide should be paid more attention; 4. in numerical simulation, the factors of unbalance force and excess pore pressure also can be used in forecasting deformation tendency of landslide.

Cockroach-inspired Traversing Narrow Obstacles for a Sprawled Hexapod Robot

Inspired by the cockroach’s use of a pitch-roll mode traverses through narrow obstacles,we improve the RHex-style robot by adding two sprawl joints to adjust the body posture,and propose a novel pitch-roll approach that enables an RHex-style robot to traverse through two cylindrical obstacles with a spacing of 90 mm,about 54%body width.First,the robot can pitch up against the obstacle on the one side by the cooperation of its rear and middle legs.Then,the robot rotates one side rear leg to kick the ground fast,meanwhile the sprawl joint on the other side rotates inward to make the robot roll and fall forward.Finally,the robot can rotate the legs on the ground to move the body forward until it crosses the obstacles.In this article,both cylinder and rectangular columns are considered as the narrow obstacles for traversing.The experiments are demonstrated by using the proposed approach,and the results show that the robot can smoothly traverse through different narrow spaces.

Bionics-based Optimization of Step-climbing Gait in a Novel Mini-RHex Robot

RHex-style robots can perform manifold moving gaits in different applications,but they have always faced a challenge of climbing up high obstacles.In this paper,the bionics-based gait optimization in an RHex-style robot is proposed for climbing steps at different heights,which even enables the robot to climb up the step with 4.2 times of the leg length.First,a thoracic flexion is designed in the robot,and an algorithm of adjusting body inclination is proposed to perform the rising stage after placing front legs on top of step,which can be applied in different RHex-style robots with different sizes.Especially,when the thoracic flexion is implemented,the robot can climb the higher step with the proposed algorithm.Second,to climbing the higher steps,a claw-shape legs-based algorithm is proposed for robot reaching the higher step and climbing it up.During the vital rising stage,when the front legs of the robot have reached the top of the step,the robot can bend the front body downward with its thoracic flexion like a cockroach,and then lift the front and middle legs alternately to move COM up and forward onto the step.The simulation analysis is utilized to verify the feasibility of the proposed algorithms.Finally,the step-climbing experiments at different heights are performed in our robot to compare with the existing works.The results of simulations and experiments show the superiority of the proposed algorithms for the improved robot due to climbing up the higher steps.