The manipulation and constraint equations are established by considering the pure rolling motion in a dexterous hand as two passive joints. According to mapping relation among the motion of the system, the differentia...The manipulation and constraint equations are established by considering the pure rolling motion in a dexterous hand as two passive joints. According to mapping relation among the motion of the system, the differential kinematics and mobility are studied. The minimal structure for realizing the task motion of the object is obtained, and the conditions for dexterous manipulation are presented. Finally, some rolling manipulations are used as examples to demonstrate the applicability of approach proposed.展开更多
This paper first analyzes in detail the signal character of early fault bearing and the advantage and effectiveness in extracting the character frequency with use of short time fourier transform. As one of the methods...This paper first analyzes in detail the signal character of early fault bearing and the advantage and effectiveness in extracting the character frequency with use of short time fourier transform. As one of the methods in monitoring the fault rolling-element bearing, a new signal processing approach, which is called Short Sample Analysis (SSA) is then proposed. This method has taken the high frequency hand of the fault beating signal as diagnostic band and collected the pulse energy in the band as diagnostic parameters, which has proved to be accurate and clear in extracting the characteristic defect frequency, with high rate in signal to noise, and reliable and convenient in real rolling element bearing monitoring system.展开更多
In rolling experiments,the performances of spider-like robot are limited greatly by its motors’driving ability;meanwhile,the ground reaction forces are so great that they damaged the rods.In this paper,we solve above...In rolling experiments,the performances of spider-like robot are limited greatly by its motors’driving ability;meanwhile,the ground reaction forces are so great that they damaged the rods.In this paper,we solve above problems both mechanically and by control.Firstly,we design the parameters of the central pattern generator(CPG)network based on the kinematics of the robot to enable a smooth rolling trajectory.And we also analyze the kinematic rolling and dynamic rolling briefly.Secondly,we add torsion springs to the passive joints of the spider-like robot aiming to make use of its energy storage capacity to compensate the insufficient torque.The simulation results show that the optimized CPG control parameters can reduce the fluctuation of the mass center and the ground reaction forces.The torsion spring can reduce the peak torque requirements of the actuated joints by 50%.展开更多
为防止无人客车智能域因参数标定误差、网络攻击等发出指令致使车辆侧翻,提出了一套基于横向安全评估的智能客车防侧翻自主决策控制系统。首先建立了车辆三自由度线性模型,并基于卡尔曼滤波进行了状态重构;其次在横向载荷转移率(Lateral...为防止无人客车智能域因参数标定误差、网络攻击等发出指令致使车辆侧翻,提出了一套基于横向安全评估的智能客车防侧翻自主决策控制系统。首先建立了车辆三自由度线性模型,并基于卡尔曼滤波进行了状态重构;其次在横向载荷转移率(Lateral-Load Transfer Rate,LTR)基础上推导出预测LTR并作为侧翻指标,同时进行了敏感量分析;然后采用了考虑路面附着系数的主动转向和全轮制动的联合控制方案,将即将失稳时的LTR稳定在设定阈值附近;最后进行仿真验证。结果表明,所设计的联合控制算法在极端工况下不仅保证客车不侧翻,且相比于纯转向控制,联合控制能在一定程度上降低路径跟踪偏差。展开更多
基金This project is supported by Scientific Research Foundation for ReturnedOverseas Chinese Scholars, Education Ministry of China and ProvincialNatural Science Foundation of Shanxi, China (No.2000C37).
文摘The manipulation and constraint equations are established by considering the pure rolling motion in a dexterous hand as two passive joints. According to mapping relation among the motion of the system, the differential kinematics and mobility are studied. The minimal structure for realizing the task motion of the object is obtained, and the conditions for dexterous manipulation are presented. Finally, some rolling manipulations are used as examples to demonstrate the applicability of approach proposed.
文摘This paper first analyzes in detail the signal character of early fault bearing and the advantage and effectiveness in extracting the character frequency with use of short time fourier transform. As one of the methods in monitoring the fault rolling-element bearing, a new signal processing approach, which is called Short Sample Analysis (SSA) is then proposed. This method has taken the high frequency hand of the fault beating signal as diagnostic band and collected the pulse energy in the band as diagnostic parameters, which has proved to be accurate and clear in extracting the characteristic defect frequency, with high rate in signal to noise, and reliable and convenient in real rolling element bearing monitoring system.
基金the Fundamental Research Funds for the Central Universities of China(No.M15JB00250)。
文摘In rolling experiments,the performances of spider-like robot are limited greatly by its motors’driving ability;meanwhile,the ground reaction forces are so great that they damaged the rods.In this paper,we solve above problems both mechanically and by control.Firstly,we design the parameters of the central pattern generator(CPG)network based on the kinematics of the robot to enable a smooth rolling trajectory.And we also analyze the kinematic rolling and dynamic rolling briefly.Secondly,we add torsion springs to the passive joints of the spider-like robot aiming to make use of its energy storage capacity to compensate the insufficient torque.The simulation results show that the optimized CPG control parameters can reduce the fluctuation of the mass center and the ground reaction forces.The torsion spring can reduce the peak torque requirements of the actuated joints by 50%.
文摘为防止无人客车智能域因参数标定误差、网络攻击等发出指令致使车辆侧翻,提出了一套基于横向安全评估的智能客车防侧翻自主决策控制系统。首先建立了车辆三自由度线性模型,并基于卡尔曼滤波进行了状态重构;其次在横向载荷转移率(Lateral-Load Transfer Rate,LTR)基础上推导出预测LTR并作为侧翻指标,同时进行了敏感量分析;然后采用了考虑路面附着系数的主动转向和全轮制动的联合控制方案,将即将失稳时的LTR稳定在设定阈值附近;最后进行仿真验证。结果表明,所设计的联合控制算法在极端工况下不仅保证客车不侧翻,且相比于纯转向控制,联合控制能在一定程度上降低路径跟踪偏差。
