自动驾驶智能汽车逐渐普及,其在通过城市路面的沟渠、井盖和减速带等特殊路面时,制动与减速时的稳定性与乘坐舒适性较差,为改善这一状况,对悬架的设计提出了更高的要求。为了提高自动驾驶智能汽车制动与减速时的稳定性,通过融合比例积...自动驾驶智能汽车逐渐普及,其在通过城市路面的沟渠、井盖和减速带等特殊路面时,制动与减速时的稳定性与乘坐舒适性较差,为改善这一状况,对悬架的设计提出了更高的要求。为了提高自动驾驶智能汽车制动与减速时的稳定性,通过融合比例积分微分(Proportional Integral Derivative,PID)与模糊算法,设计了针对这些特殊路面的主动悬架模糊PID控制器,在Matlab/Simulink软件中搭建了半车主动悬架仿真模型,通过惯性测量单元(Inertial Measurement Unit,IMU)实车测量了沟渠路面的路面激励信息,并完成仿真试验。结果表明,当自动驾驶智能汽车在C级路面和沟渠路面行驶时,设计的主动悬架模糊PID控制器较单一算法的控制器更有效地降低了车身垂向加速度、车身俯仰角加速度、车轮动载荷和悬架动行程,改善了悬架性能。展开更多
Two simple and effective control strategies for a multi-axle heavy truck, modified skyhook damping (MSD) control and proportional-integration-derivative (PID) control, were implemented into functional virtual prototyp...Two simple and effective control strategies for a multi-axle heavy truck, modified skyhook damping (MSD) control and proportional-integration-derivative (PID) control, were implemented into functional virtual prototype (FVP) model and compared in terms of road friendliness and ride comfort. A four-axle heavy truck-road coupling system model was established using FVP technology and validated through a ride comfort test. Then appropriate passive air suspensions were chosen to replace the rear tandem suspensions of the original truck model for preliminary optimization. The mechanical properties and time lag of dampers were taken into account in simulations of MSD and PID semi-active dampers implemented using MATLAB/Simulink. Through co-simulations with Adams and MATLAB, the effects of semi-active MSD and PID control were analyzed and compared, and control parameters which afforded the best comprehensive performance for each control strategy were chosen. Simulation results indicate that compared with the passive air suspension truck, semi-active MSD control improves both ride comfort and road-friendliness markedly, with optimization ratios of RMS vertical acceleration and RMS tyre force ranging from 10.1% to 44.8%. However, semi-active PID control only reduces vertical vibration of the driver's seat by 11.1%, 11.1% and 10.9% on A, B and C level roads respectively. Both strategies are robust to the variation of road level.展开更多
The most usual way of using chemical method to protect crop against weed, insects, and fungi is spraying the mixture of chemicals and water onto crop through the nozzles. Sprayers usually moved on the field by tractor...The most usual way of using chemical method to protect crop against weed, insects, and fungi is spraying the mixture of chemicals and water onto crop through the nozzles. Sprayers usually moved on the field by tractor, and tractor induced unwanted vibration to sprayer because of uneven soil or terrain. This oscillation leads to over-doses and under-doses of chemical sprayed on the field. For this reason, many commercial and some theoretical suspension were made to reduce undesirable vibration. Therefore, in this study a finite element based model was established to represent the dynamic behavior of spray boom structure with 8m width. The first tenth natural frequencies were obtained between 9.25 Hz to 1,182.5 Hz. Also, a passive vertical suspension was designed to remove unwanted vibration with 0.5 vibration transmissibility. Finally, the suspension system was simulated to be as certain of its efficiency. The results of simulation have good agreement to the proposed aim.展开更多
文摘自动驾驶智能汽车逐渐普及,其在通过城市路面的沟渠、井盖和减速带等特殊路面时,制动与减速时的稳定性与乘坐舒适性较差,为改善这一状况,对悬架的设计提出了更高的要求。为了提高自动驾驶智能汽车制动与减速时的稳定性,通过融合比例积分微分(Proportional Integral Derivative,PID)与模糊算法,设计了针对这些特殊路面的主动悬架模糊PID控制器,在Matlab/Simulink软件中搭建了半车主动悬架仿真模型,通过惯性测量单元(Inertial Measurement Unit,IMU)实车测量了沟渠路面的路面激励信息,并完成仿真试验。结果表明,当自动驾驶智能汽车在C级路面和沟渠路面行驶时,设计的主动悬架模糊PID控制器较单一算法的控制器更有效地降低了车身垂向加速度、车身俯仰角加速度、车轮动载荷和悬架动行程,改善了悬架性能。
基金Projects(51078087, 51178158) supported by the National Natural Science Foundation of ChinaProject(11040606Q39) supported by the Natural Science Foundation of Anhui Province, ChinaProjects(2012HGQC0015, 2011HGBZ0945) supported by the Fundamental Research Funds for the Central Universities
文摘Two simple and effective control strategies for a multi-axle heavy truck, modified skyhook damping (MSD) control and proportional-integration-derivative (PID) control, were implemented into functional virtual prototype (FVP) model and compared in terms of road friendliness and ride comfort. A four-axle heavy truck-road coupling system model was established using FVP technology and validated through a ride comfort test. Then appropriate passive air suspensions were chosen to replace the rear tandem suspensions of the original truck model for preliminary optimization. The mechanical properties and time lag of dampers were taken into account in simulations of MSD and PID semi-active dampers implemented using MATLAB/Simulink. Through co-simulations with Adams and MATLAB, the effects of semi-active MSD and PID control were analyzed and compared, and control parameters which afforded the best comprehensive performance for each control strategy were chosen. Simulation results indicate that compared with the passive air suspension truck, semi-active MSD control improves both ride comfort and road-friendliness markedly, with optimization ratios of RMS vertical acceleration and RMS tyre force ranging from 10.1% to 44.8%. However, semi-active PID control only reduces vertical vibration of the driver's seat by 11.1%, 11.1% and 10.9% on A, B and C level roads respectively. Both strategies are robust to the variation of road level.
文摘The most usual way of using chemical method to protect crop against weed, insects, and fungi is spraying the mixture of chemicals and water onto crop through the nozzles. Sprayers usually moved on the field by tractor, and tractor induced unwanted vibration to sprayer because of uneven soil or terrain. This oscillation leads to over-doses and under-doses of chemical sprayed on the field. For this reason, many commercial and some theoretical suspension were made to reduce undesirable vibration. Therefore, in this study a finite element based model was established to represent the dynamic behavior of spray boom structure with 8m width. The first tenth natural frequencies were obtained between 9.25 Hz to 1,182.5 Hz. Also, a passive vertical suspension was designed to remove unwanted vibration with 0.5 vibration transmissibility. Finally, the suspension system was simulated to be as certain of its efficiency. The results of simulation have good agreement to the proposed aim.
