The clearances appear in chain link hinges induced by manufacturing tolerance or wear of components are the most important factor that influences the dynamic performance of the intermittent roller chain drives. Due to...The clearances appear in chain link hinges induced by manufacturing tolerance or wear of components are the most important factor that influences the dynamic performance of the intermittent roller chain drives. Due to the existence of the clearances in chain link hinges, the serious impact vibration phenomenon which influences the stability and the position accuracy of the chain drive system would be caused in the intermittent motion. But, the problem may be that a reasonable modeling on the chain with clearances is difficult due to the large clearance＇s number in chain system and the fact that the clearance＇ size are different. Currently, the studies on the dynamics of the intermittent roller chain considering the multi-clearance＇ joints are rare. Most research works have only focused on the constant moving chains. Taking the intermittent roller chain system as an object, this paper designs and builds the experimental device of this kind of mechanical system. The Longitudinal vibration response of the intermittent chain under the different motion laws was tested. The experimental study shows that the clearances presented in chain link hinges can cause severe impact vibration in the intermittent motion of chain. In subsequent work, the dynamic model of the intermittent roller chain system with the multi-clearance＇ joints was established. By calculating the dynamic response of this kind of mechanical system under the different motion laws, the effect of the clearances on the dynamic response of the intermittent chain drive system was analyzed. The theoretical simulation shows that the serious impact vibration phenomenon of the chain system can be caused by the clearances at the start accelerating period, and the chain drive system is often accompanied by the severe shock and vibration at the moment that the chain moves from the acceleration period to deceleration period. The research conclusions made by the experimental and theoretical studies indicate that the use of motion laws with small and continuous 展开更多
基金supported by National Natural Science Foundation of China (Grant No. 50605060)Tianjin Municipal Natural Science Foundation of China (Grant No. 06YFJMJC03300)
文摘The clearances appear in chain link hinges induced by manufacturing tolerance or wear of components are the most important factor that influences the dynamic performance of the intermittent roller chain drives. Due to the existence of the clearances in chain link hinges, the serious impact vibration phenomenon which influences the stability and the position accuracy of the chain drive system would be caused in the intermittent motion. But, the problem may be that a reasonable modeling on the chain with clearances is difficult due to the large clearance＇s number in chain system and the fact that the clearance＇ size are different. Currently, the studies on the dynamics of the intermittent roller chain considering the multi-clearance＇ joints are rare. Most research works have only focused on the constant moving chains. Taking the intermittent roller chain system as an object, this paper designs and builds the experimental device of this kind of mechanical system. The Longitudinal vibration response of the intermittent chain under the different motion laws was tested. The experimental study shows that the clearances presented in chain link hinges can cause severe impact vibration in the intermittent motion of chain. In subsequent work, the dynamic model of the intermittent roller chain system with the multi-clearance＇ joints was established. By calculating the dynamic response of this kind of mechanical system under the different motion laws, the effect of the clearances on the dynamic response of the intermittent chain drive system was analyzed. The theoretical simulation shows that the serious impact vibration phenomenon of the chain system can be caused by the clearances at the start accelerating period, and the chain drive system is often accompanied by the severe shock and vibration at the moment that the chain moves from the acceleration period to deceleration period. The research conclusions made by the experimental and theoretical studies indicate that the use of motion laws with small and continuous
文摘为实现差速驱动机器人在避障环境下的平滑最优路径规划,提出一种基于Bezier曲线的差速驱动机器人混合避障路径规划算法.首先,建立差速驱动机器人运动模型,用于操控左右两个驱动轮线速率,完成机器人转弯及非匀速运动;其次,利用Bezier曲线描述路径状态,将路径规划问题转换为产生Bezier曲线有限点方位优化问题,提升机器人的运动平滑性;最后,引入遗传算法将二维路径编码简化为一维编码问题,将路边约束、动态避障需求及最短路径需求混合成适应度函数,使机器人尽快脱离局部极小解,成功绕过障碍物抵达目标点.仿真实验结果表明,该方法的避障路径规划效果较好,避障路径距离为30.19 m,且避障用时低于对比方法,最长避障用时为5.3 min.
