A k-shortest path based algorithm considering layout density and signal integrity for good buffer candidatelocations is proposed in this paper. Theoretical results for computing the maximal distance betweenbuffers are...A k-shortest path based algorithm considering layout density and signal integrity for good buffer candidatelocations is proposed in this paper. Theoretical results for computing the maximal distance betweenbuffers are derived under the timing, noise and slew rate constraints. By modifying the traditional uniformwire segmenting strategy and considering the impact of tile size on density penalty function, this work proposesk-shortest path algorithm to find the buffer insertion candidate locations. The experiments show thatthe buffers inserted can significantly optimize the design density, alleviate signal degradation, save thenumber of buffers inserted and the overall run time.展开更多
Thanks to the special physical architectures and various locomotion gaits,snake robots may offer significant benefits over traditional legged or wheeled locomotion designs in vast types of scenarios.This paper propose...Thanks to the special physical architectures and various locomotion gaits,snake robots may offer significant benefits over traditional legged or wheeled locomotion designs in vast types of scenarios.This paper proposes an innovative snake robot with digitally-actuated Stewart platforms as its modules and mainly focuses on the simulations of various snake gaits.Three categories of fitting algorithms are elaborated in simulations of lateral undulation and Configuration-Fitting Algorithm of Four Modules is demonstrated as a universal gait fitting algorithm for all kinds of snake robots with binary actuators.Several typical snake gaits are simulated and the results demonstrate the excellent mobility of the snake robot.展开更多
Obstacle avoidance is quite an important issue in the field of legged robotic applications, such as rescuing and detecting in complicated environment. Most related researchers focused on the legged robot’s gait gener...Obstacle avoidance is quite an important issue in the field of legged robotic applications, such as rescuing and detecting in complicated environment. Most related researchers focused on the legged robot’s gait generation after ssuming that obstacles have been detected and the walking path has been given. In this paper we propose and validate a novel obstacle avoidance framework for a six-legged walking robot Hexapod-III in unknown environment. Throughout the paper we highlight three themes: (1) The terrain map modeling and the obstacle detection; (2) the obstacle avoidance path planning method; (3) motion planning for the legged robot. Concretely, a novel geometric feature grid map (GFGM) is proposed to describe the terrain. Based on the GFGM, the obstacle detection algorithm is presented. Then the concepts of virtual obstacles and safe conversion pose are introduced. Virtual obstacles restrict the robot to walk on the detection terrain. A safe path based on Bezier curves, passing through safe conversion poses, is obtained by minimizing a penalty function taking into account the path length subjected to obstacle avoidance. Thirdly, motion planning for the legged robot to walk along the generated path is discussed in detail. At last, we apply the proposed framework to the Hexapod-III robot. The experimental result shows that our methodology allows the robot to walk safely without encountering with any obstacles in unknown environment.展开更多
We theoretically investigate the multistable behavior of a hybrid optomechanical system, in which a charged mechanical resonator is coupled via Coulomb interaction to an optomechanical cavity containing an optical par...We theoretically investigate the multistable behavior of a hybrid optomechanical system, in which a charged mechanical resonator is coupled via Coulomb interaction to an optomechanical cavity containing an optical parametric amplifier （OPA）. It is shown that the multistable behavior of the mean intracavity photon number can be controlled flexibly by adjusting the nonlinear gain parameter of the OPA, the phase of the field pumping the OPA, the power and frequency of the field driving the cavity, and the Coulomb coupling strength between the two charged mechanical resonators. In particular, the increase of the nonlinear gain parameter can result in a transition from bistability to tristability. Moreover, the effect of the Coulomb coupling strength on the bistable behavior of the steady-state positions of the two mechanical resonators is discussed.展开更多
基金Supported by the National Key Project of Scientific and Technical Supporting Programs (No. 2006BAK07B04).
文摘A k-shortest path based algorithm considering layout density and signal integrity for good buffer candidatelocations is proposed in this paper. Theoretical results for computing the maximal distance betweenbuffers are derived under the timing, noise and slew rate constraints. By modifying the traditional uniformwire segmenting strategy and considering the impact of tile size on density penalty function, this work proposesk-shortest path algorithm to find the buffer insertion candidate locations. The experiments show thatthe buffers inserted can significantly optimize the design density, alleviate signal degradation, save thenumber of buffers inserted and the overall run time.
基金supported by the Research Fund of State Key Laboratory of Mechanical System and Vibration,China(Grant No.MSV-2010-07)
文摘Thanks to the special physical architectures and various locomotion gaits,snake robots may offer significant benefits over traditional legged or wheeled locomotion designs in vast types of scenarios.This paper proposes an innovative snake robot with digitally-actuated Stewart platforms as its modules and mainly focuses on the simulations of various snake gaits.Three categories of fitting algorithms are elaborated in simulations of lateral undulation and Configuration-Fitting Algorithm of Four Modules is demonstrated as a universal gait fitting algorithm for all kinds of snake robots with binary actuators.Several typical snake gaits are simulated and the results demonstrate the excellent mobility of the snake robot.
基金supported by the National Basic Research Program of China (Grant No. 2013CB035501)
文摘Obstacle avoidance is quite an important issue in the field of legged robotic applications, such as rescuing and detecting in complicated environment. Most related researchers focused on the legged robot’s gait generation after ssuming that obstacles have been detected and the walking path has been given. In this paper we propose and validate a novel obstacle avoidance framework for a six-legged walking robot Hexapod-III in unknown environment. Throughout the paper we highlight three themes: (1) The terrain map modeling and the obstacle detection; (2) the obstacle avoidance path planning method; (3) motion planning for the legged robot. Concretely, a novel geometric feature grid map (GFGM) is proposed to describe the terrain. Based on the GFGM, the obstacle detection algorithm is presented. Then the concepts of virtual obstacles and safe conversion pose are introduced. Virtual obstacles restrict the robot to walk on the detection terrain. A safe path based on Bezier curves, passing through safe conversion poses, is obtained by minimizing a penalty function taking into account the path length subjected to obstacle avoidance. Thirdly, motion planning for the legged robot to walk along the generated path is discussed in detail. At last, we apply the proposed framework to the Hexapod-III robot. The experimental result shows that our methodology allows the robot to walk safely without encountering with any obstacles in unknown environment.
基金supported by the National Natural Science Foundation of China(Grant No.11304110)the Natural Science Foundation of Jiangsu Province(Grant Nos.BK20130413 and BK20140450)the Natural Science Foundation of the Jiangsu Higher Education Institutions of China (Grant No.13KJB140002)
文摘We theoretically investigate the multistable behavior of a hybrid optomechanical system, in which a charged mechanical resonator is coupled via Coulomb interaction to an optomechanical cavity containing an optical parametric amplifier （OPA）. It is shown that the multistable behavior of the mean intracavity photon number can be controlled flexibly by adjusting the nonlinear gain parameter of the OPA, the phase of the field pumping the OPA, the power and frequency of the field driving the cavity, and the Coulomb coupling strength between the two charged mechanical resonators. In particular, the increase of the nonlinear gain parameter can result in a transition from bistability to tristability. Moreover, the effect of the Coulomb coupling strength on the bistable behavior of the steady-state positions of the two mechanical resonators is discussed.
