There is an increasing awareness of the need to reduce traffic accidents and fatality due to vehicle collision.Post-impact hazards can be more serious as the driver may fail to maintain effective control after collisi...There is an increasing awareness of the need to reduce traffic accidents and fatality due to vehicle collision.Post-impact hazards can be more serious as the driver may fail to maintain effective control after collisions.To avoid subsequent crash events and to stabilize the vehicle,this paper proposes a post-impact motion planning and stability control method for autonomous vehicles.An enabling motion planning method is proposed for post-impact situations by combining the polynomial curve and artificial potential field while considering obstacle avoidance.A hierarchical controller that consists of an upper and a lower controller is then developed to track the planned motion.In the upper controller,a time-varying linear quadratic regulator is presented to calculate the desired generalized forces.In the lower controller,a nonlinear-optimization-based torque allocation algorithm is proposed to optimally coordinate the actuators to realize the desired generalized forces.The proposed scheme is verified under comprehensive driving scenarios through hardware-in-loop tests.展开更多
The work of the paper focused on the post impact of oil spill contamination of groundwater in Bassambiri Nembe Bayelsa State. Groundwater samples were sampled from hand dug wells from eight stations including the cont...The work of the paper focused on the post impact of oil spill contamination of groundwater in Bassambiri Nembe Bayelsa State. Groundwater samples were sampled from hand dug wells from eight stations including the control point for physico-chemical investigation using sterilized glass bottles. Sampling was carried out upstream and downstream on the Santa Barbara River across the stations and the results are as follows surface water pH ranged 6.90 - 7.50, electrical conductivity 19739.41 μS/cm - 28920.64 μS/cm and Chloride 6019.63 - 9274.82 mg/l. The Total Dissolved Solids (TDS) varied from 10472.72 mg/l - 16538.19 mg/l dissolved oxygen (DO) 6.21 mg/l - 7.371 mg/l while the mean biochemical oxygen demand (BOD) 0.09 ± 0.52 mg/l - 2.4 ± 0.81 mg/l, temperature 28.04℃ - 31.79℃ while total alkalinity is 43.95 mg/L -73.87 mg/L. Calcium ion ranged 375.68 mg/l - 536.72 mg/l, Magnesium ion 88.35 - 243.24 mg/l and Potassium ion 41.27 - 121.17 mg/l. The results of the study showed that the pH, salinity, alkalinity, total suspended solids (TSS), Chlorides, Phosphates, and Nitrates are within permissible limits of the WHO, however the electrical conductivity, TDS, turbidity, DO, BOD, and hardness exceeded WHO permissible limits for drinking water. Total Petroleum Hydrocarbon (TPH) and Heavy metals had low concentrations in the Santa Barbara River across the study area suggesting that surface water is not polluted. However, the surfactants used initially to contain the oil pollution were effective based on this research.展开更多
基金Beijing Municipal Science and Technology Commission via the Beijing Nova Program(Grant No.Z201100006820007).
文摘There is an increasing awareness of the need to reduce traffic accidents and fatality due to vehicle collision.Post-impact hazards can be more serious as the driver may fail to maintain effective control after collisions.To avoid subsequent crash events and to stabilize the vehicle,this paper proposes a post-impact motion planning and stability control method for autonomous vehicles.An enabling motion planning method is proposed for post-impact situations by combining the polynomial curve and artificial potential field while considering obstacle avoidance.A hierarchical controller that consists of an upper and a lower controller is then developed to track the planned motion.In the upper controller,a time-varying linear quadratic regulator is presented to calculate the desired generalized forces.In the lower controller,a nonlinear-optimization-based torque allocation algorithm is proposed to optimally coordinate the actuators to realize the desired generalized forces.The proposed scheme is verified under comprehensive driving scenarios through hardware-in-loop tests.
文摘The work of the paper focused on the post impact of oil spill contamination of groundwater in Bassambiri Nembe Bayelsa State. Groundwater samples were sampled from hand dug wells from eight stations including the control point for physico-chemical investigation using sterilized glass bottles. Sampling was carried out upstream and downstream on the Santa Barbara River across the stations and the results are as follows surface water pH ranged 6.90 - 7.50, electrical conductivity 19739.41 μS/cm - 28920.64 μS/cm and Chloride 6019.63 - 9274.82 mg/l. The Total Dissolved Solids (TDS) varied from 10472.72 mg/l - 16538.19 mg/l dissolved oxygen (DO) 6.21 mg/l - 7.371 mg/l while the mean biochemical oxygen demand (BOD) 0.09 ± 0.52 mg/l - 2.4 ± 0.81 mg/l, temperature 28.04℃ - 31.79℃ while total alkalinity is 43.95 mg/L -73.87 mg/L. Calcium ion ranged 375.68 mg/l - 536.72 mg/l, Magnesium ion 88.35 - 243.24 mg/l and Potassium ion 41.27 - 121.17 mg/l. The results of the study showed that the pH, salinity, alkalinity, total suspended solids (TSS), Chlorides, Phosphates, and Nitrates are within permissible limits of the WHO, however the electrical conductivity, TDS, turbidity, DO, BOD, and hardness exceeded WHO permissible limits for drinking water. Total Petroleum Hydrocarbon (TPH) and Heavy metals had low concentrations in the Santa Barbara River across the study area suggesting that surface water is not polluted. However, the surfactants used initially to contain the oil pollution were effective based on this research.
