Showing papers by "Hengyu Li published in 2015"
TL;DR: A bionic eyes system of active compensation for robot visual error is proposed inspired by the binocular VOR to solve the problem of vision instability caused by attitude variation of the robot working under bumpy environment.
Abstract: With the wide application of robot in unstructured environment, cognizing and understanding environmental information accurately is the key for robots to complete the task. Thus, visual stability problems in these robot control systems have become important design issues. In this paper, to solve the problem of vision instability caused by attitude variation of the robot working under bumpy environment, a bionic eyes system of active compensation for robot visual error is proposed inspired by the binocular VOR. The bionic vision system is developed based on features of oculomotor behaviors and bionic control algorithm of the binocular VOR. According to the behaviors features of eye movement, the bionic eye mechanism is designed by using a 3-DoF spherical parallel mechanism(SPM). Meanwhile, to improve the performance, the mechanism parameters of SPM are optimized by utilizing the worst-case performance index as the optimizing target in required workspace. An adaptive control model of the binocular VOR is established on neural control mechanisms of eye movement, and the model is used as the bionic control algorithm to drive and control the eye mechanism. The results indicate that the model can actively compensate the visual errors from postural changes of robot. Physical robot experiments also show that the system is robust even with bumpy environment.
20 citations
08 Jun 2015
TL;DR: In this article, a wind power generation system experimental platform is established, and wind generator external characteristics are measured directly by the experimental platform, so output power, input wind energy, tip speed ratio and wind energy utilization coefficient are calculated by the measured data, and draw the appropriate output characteristic curve and analyze the experimental results.
Abstract: This paper, wind power generation system experimental platform is established, and wind generator external characteristics are measured. Vertical axis wind turbine system features parameters are measured directly by the experimental platform, so output power, input wind energy, tip speed ratio and wind energy utilization coefficient et al. parameters are calculated by the measured data, and draw the appropriate output characteristic curve and analyze the experimental results.
10 citations
TL;DR: Experimental results demonstrate the effectiveness and robustness of the bioinspired tracking system using bionic spherical parallel mechanism inspired by head-eye coordination, designed to make the robot track dynamic objects when the robot travels through transmittable terrains, especially bumpy environment.
Abstract: A symmetric Kullback-Leibler metric based tracking system, capable of tracking moving targets, is presented for a bionic spherical parallel mechanism to minimize a tracking error function to simulate smooth pursuit of human eyes. More specifically, we propose a real-time moving target tracking algorithm which utilizes spatial histograms taking into account symmetric Kullback-Leibler metric. In the proposed algorithm, the key spatial histograms are extracted and taken into particle filtering framework. Once the target is identified, an image-based control scheme is implemented to drive bionic spherical parallel mechanism such that the identified target is to be tracked at the center of the captured images. Meanwhile, the robot motion information is fed forward to develop an adaptive smooth tracking controller inspired by the Vestibuloocular Reflex mechanism. The proposed tracking system is designed to make the robot track dynamic objects when the robot travels through transmittable terrains, especially bumpy environment. To perform bumpy-resist capability under the condition of violent attitude variation when the robot works in the bumpy environment mentioned, experimental results demonstrate the effectiveness and robustness of our bioinspired tracking system using bionic spherical parallel mechanism inspired by head-eye coordination.
6 citations
TL;DR: In this paper, a wind-driven land-yacht robot which will be applied in polar expedition is presented, where the main power of robot is provided by wing sail, improving the efficiency of wing sail is the key for its motion.
Abstract: A wind-driven land-yacht robot which will be applied in polar expedition is presented in this article. As the main power of robot is provided by wing sail, improving the efficiency of wing sail is the key for its motion. Wing sail is composed of airfoil, so airfoil theory is researched first, and then several airfoils and their aerodynamic performance are compared, and a high-efficiency airfoil is selected. After that, overturning torque and start wind speed of robot are analyzed to determine the size of the wing sail. At last, the wing sail is manufactured and checked, and it is tested by start wind speed experiments, running speed experiments, steering motion, and obstacle avoidance experiments. The minimum start wind speed is 6 m/s. When wind speed is 10.3 m/s and angle of attack is 90°, running velocity of robot is 1.285 m/s. A land-yacht robot can run steering motion well and avoid obstacle to the target. The result shows that wing sail satisfies the motion requirement of land-yacht robot.
5 citations
TL;DR: This work presents an analysis of a zoom system based on the variable focal power lens, and it is demonstrated how the analysis can be used in zoom system design.
Abstract: We present our analysis of a zoom system based on the variable focal power lens, and we demonstrate how our analysis can be used in zoom system design. The transverse magnification is considered as an independent first-order optics control parameter in the zoom system. The zoom system equations are established through the use of matrix optics. Formulas related to the zoom principles and performance of such optical systems are derived, and numerical and theoretical values are compared using examples.
3 citations
03 Sep 2015
TL;DR: In this article, a geometric model of the large-belt width driving roller was built, static analysis was made based on finite element analysis method, and the roller body structure was analyzed by post-processing along the circumferential direction and axial direction respectively.
Abstract: As a key component of the large-belt width conveyor, establishing mechanical model and adopting effective method to improve the design performance of the large-belt width roller is very important. In this paper, mechanical analysis was employed in large-belt width conveyor driving roller for the theoretical foundation of the subsequent analysis. The geometric model of the large-belt width driving roller was built, static analysis was made based on finite element analysis method, and the roller body structure was analyzed by post-processing along the circumferential direction and axial direction respectively. The results show that under the circumstance of ensuring welding quality, the damage of the roller will occur at a certain distance toward the central shell from the connection position of the inside flange and the roller shell, therefore the welding position of the cast welding structure at both ends should avoid the dangerous zone. Analyzing the stress and strain distribution of the roller along the axial direction can predict trends in stress distribution and deformation of the large-belt width roller.
2 citations
08 Jun 2015
TL;DR: A polar wind-driven vehicle is proposed in this article, where the driving force and rolling force of the vehicle are optimized to control the system and navigate in order to achieve a long time and wide range exploration in polar environment.
Abstract: Currently, robots' range of exploration is quite limited due to the finite number of batteries or fuel so that robots can't achieve a long time and wide range exploration which also can't meet the requirement of the polar expedition A polar wind-driven vehicle is proposed in this paper Dynamics analysis of the wind-driven system is used to optimize the driving force and rolling force in order to control the system and navigate The airfoil design has a crucial influence on the aerodynamic characteristics of wind-driven system Through a comparative analysis of several mature airfoils, we select the final airfoil We find the only uncertain variable is the drag force of the vehicle body and designed a set of simulation experiments to find the characteristics of the drag coefficient of the vehicle body Meanwhile, we obtain the conclusion that the body drag coefficients are decreasing along with the increasing of prevailing wind speed And it changes slightly at the high wind speed in polar environment
1 citations
01 Dec 2015
TL;DR: A people detection and tracking system using combination of a several new techniques for mobile robots, plan-view maps, depth weighted histograms, and GNN data association to detect human candidates is proposed.
Abstract: Understanding how humans move through the scene is a key issue of decision-making for an autonomous mobile robot in crown people zones. So accurately detecting and tracking people from a mobile platform can help improve interaction effective and efficient. In this paper, we proposed a people detection and tracking system using combination of a several new techniques for mobile robots, plan-view maps, depth weighted histograms, and GNN data association. We proposed a spatial region of interest based plan-view maps to detect human candidates. Firstly, point cloud sub-clusters were segmented for candidate detection. Two different plan-view maps, named occupancy map and height map, were employed to identify human candidates from point cloud sub-clusters. Meanwhile, a depth weighted histogram was extracted to feature a human candidate. Then, a particle filter algorithm was adopted to track human's motion. Finally, data association was set up to re-identify humans which were tracked. Extensive experiments demonstrated the effectiveness and robustness of our human detection and tracking system.