The motion of three German Shepherd Dogs on a treadmill was recorded using a three-dimensional motion capture system. The locomotion speed of the dog was respectively set at 4km·h^-1, 5.5km·h^-1, 7 km·h...The motion of three German Shepherd Dogs on a treadmill was recorded using a three-dimensional motion capture system. The locomotion speed of the dog was respectively set at 4km·h^-1, 5.5km·h^-1, 7 km·h^-1 and 8.5 km·h^-1. By processing the acquired data, the joint trajectories of the dogs＇ hind limbs were computed and a time series analysis was conducted. Joint angle-angle diagrams were obtained and the Lyapunov exponents were computed. Results show that the stability decreased when speed increased, which can be attributed to the decrease in the stance phase respect to the swing phase when speed is increased. Results also show that the dogs changed gait during the tests, namely walking in the range of 4 km·h^-1 to 7 km·h^-1 and pacing at 8.5 km·h^-1 A significant drop in stability was observed from walking to pacing.展开更多
In this paper,a structural analysis is performed to gain insights on the synergistic mechanical amplification effect thatCampaniform sensilla have when combined in an array configuration.In order to simplify the analy...In this paper,a structural analysis is performed to gain insights on the synergistic mechanical amplification effect thatCampaniform sensilla have when combined in an array configuration.In order to simplify the analysis performed in this preliminaryinvestigation,an array of four holes in a single orthotropic lamina is considered.Firstly,a Finite Element Method(FEM) analysis is performed to discretely assess the influence that different geometrical parameters have on the mechanicalamplification properties of the array.Secondly,an artificial neural network is used to obtain an approximated multi-dimensionalcontinuous function,which models the relationship between the geometrical parameters and the amplification properties of thearray.Thirdly,an optimization is performed to identify the geometrical parameters yielding the maximum mechanical amplification.Finally,results are validated with an additional FEM simulation performed by varying geometrical parameters in theneighborhood of the identified optimal parameters.The method proposed in this paper can be fully automated and used to solvea wide range of optimization problems aimed at identifying optimal configurations of strain sensors inspired by Campaniformsensilla.展开更多
Vibrational behavior of thermally actuated cantilever micro-beams and their mechanical response at moderately high frequency under a non-harmonic periodic loading is studied in this paper. Two different configurations...Vibrational behavior of thermally actuated cantilever micro-beams and their mechanical response at moderately high frequency under a non-harmonic periodic loading is studied in this paper. Two different configurations are considered: 1) a straight beam with two actuation layers on top and bottom which utilizes the bimorph effect to induce bending;2) a uniform beam with base excitation, where the beam is mounted on an actuator which moves it periodically at its base perpendicular to its axis. Generally, vibrating micro-cantilevers are required to oscillate at a specified frequency. In order to increase the efficiency of the system, and achieve deflections with low power consumption, geometrical features of the beams can be quantified so that the required vibrating frequency matches the natural frequencies of the beam. A parametric modal analysis is conducted on two configurations of micro-cantilever and the first natural frequency of the cantilevers as a function of geometrical parameters is extracted. To evaluate vibrational behavior and thermo-mechanical efficiency of micro-cantilevers as a function of their geometrical parameters and input power, a case study with a specified vibrating frequency is considered. Due to significant complexities in the loading conditions and thermo-mechanical behavior, this task can only be tackled via numerical methods. Selecting the geometrical parameters in order to induce resonance at the nominal frequency, non-linear time-history (transient) thermo-mechanical finite element analysis (using ANSYS) is run on each configuration to study its response to the periodic heating input. Approaches to improve the effectiveness of actuators in each configuration based on their implementation are investigated.展开更多
基金Acknowledgement This work was supported by the National Science Foundation of China （Grant No. 50875108）, and the Natural Sciences and Engineering Research Council of Canada （NSERC）.
文摘The motion of three German Shepherd Dogs on a treadmill was recorded using a three-dimensional motion capture system. The locomotion speed of the dog was respectively set at 4km·h^-1, 5.5km·h^-1, 7 km·h^-1 and 8.5 km·h^-1. By processing the acquired data, the joint trajectories of the dogs＇ hind limbs were computed and a time series analysis was conducted. Joint angle-angle diagrams were obtained and the Lyapunov exponents were computed. Results show that the stability decreased when speed increased, which can be attributed to the decrease in the stance phase respect to the swing phase when speed is increased. Results also show that the dogs changed gait during the tests, namely walking in the range of 4 km·h^-1 to 7 km·h^-1 and pacing at 8.5 km·h^-1 A significant drop in stability was observed from walking to pacing.
基金supported by the Natural Sciences and Engineering Research Council (NSERC) of Canada and CMC Microsystems
文摘In this paper,a structural analysis is performed to gain insights on the synergistic mechanical amplification effect thatCampaniform sensilla have when combined in an array configuration.In order to simplify the analysis performed in this preliminaryinvestigation,an array of four holes in a single orthotropic lamina is considered.Firstly,a Finite Element Method(FEM) analysis is performed to discretely assess the influence that different geometrical parameters have on the mechanicalamplification properties of the array.Secondly,an artificial neural network is used to obtain an approximated multi-dimensionalcontinuous function,which models the relationship between the geometrical parameters and the amplification properties of thearray.Thirdly,an optimization is performed to identify the geometrical parameters yielding the maximum mechanical amplification.Finally,results are validated with an additional FEM simulation performed by varying geometrical parameters in theneighborhood of the identified optimal parameters.The method proposed in this paper can be fully automated and used to solvea wide range of optimization problems aimed at identifying optimal configurations of strain sensors inspired by Campaniformsensilla.
文摘Vibrational behavior of thermally actuated cantilever micro-beams and their mechanical response at moderately high frequency under a non-harmonic periodic loading is studied in this paper. Two different configurations are considered: 1) a straight beam with two actuation layers on top and bottom which utilizes the bimorph effect to induce bending;2) a uniform beam with base excitation, where the beam is mounted on an actuator which moves it periodically at its base perpendicular to its axis. Generally, vibrating micro-cantilevers are required to oscillate at a specified frequency. In order to increase the efficiency of the system, and achieve deflections with low power consumption, geometrical features of the beams can be quantified so that the required vibrating frequency matches the natural frequencies of the beam. A parametric modal analysis is conducted on two configurations of micro-cantilever and the first natural frequency of the cantilevers as a function of geometrical parameters is extracted. To evaluate vibrational behavior and thermo-mechanical efficiency of micro-cantilevers as a function of their geometrical parameters and input power, a case study with a specified vibrating frequency is considered. Due to significant complexities in the loading conditions and thermo-mechanical behavior, this task can only be tackled via numerical methods. Selecting the geometrical parameters in order to induce resonance at the nominal frequency, non-linear time-history (transient) thermo-mechanical finite element analysis (using ANSYS) is run on each configuration to study its response to the periodic heating input. Approaches to improve the effectiveness of actuators in each configuration based on their implementation are investigated.
