Navigation and control based on integral-uncertainty observer for unmanned jet aircraft

A nonlinear integral-uncertainty observer is presented, which can estimate the integral of measurement output signal and the uncertainty in system, synchronously. In order to be satisfied with the existing hardware computational environments and to select the parameters more easily, a simplified linear version of the nonlinear integral-uncertainty observer is also developed. The effectiveness of the proposed observers are verified through the numerical simulations and experiments: i) through the integral-uncertainty observers, the attitude angle and the uncertainties in attitude dynamics are estimated synchronously from the measurements of angular velocity, and the estimate results by the two observers are compared; ii) a control law is designed based on the observers to drive the jet aircraft to track a reference trajectory

Mitigating Greenhouse Gas Emissions from Winter Production of Agricultural Greenhouses

Consuming conventional fossil fuel, such as coal, natural gas, and oil, to heat agricultural greenhouses has contributed to the climate change and air pollutions regionally and globally, so the clean energy sources have been increasingly applied to replace fossil energies in heating agricultural greenhouses, especially in urban area. To assess the environment performance (e.g., greenhouse gas (GHG) emissions) of the ground source heat pump system (GSHPs) for heating agricultural greenhouses in urban area, a GSHPs using the shallow geothermal energy (SGE) in groundwater was applied to heat a Chinese solar greenhouse (G1) and a multispan greenhouse (G2) in Beijing (latitude 39°40′ N), the capital city of China. Emission rates of the GSHPs for heating the G1 and G2 were quantified to be 0.257–0.879 g CO2 eq. m−2 day−1. The total GHG emissions from heating greenhouses in Beijing with the GSHPs were quantified as 1.7–2.9 Gt CO2 eq. year−1 based on the electricity from the coal-fired power plant (CFPP) and the gas-fired power plant (GFPP). Among different stages of the SGE flow, the SGE promotion contributed most GHG emissions (66%) in total due to the higher consumption of electricity in compressors. The total GHG emissions from greenhouses heating with the coal-fired heating system (CFHs) and gas-fired heating system (GFHs) were quantified as 2.3–5.2 Gt CO2 eq. year−1 in Beijing. Heating the G1 and G2 with the GSHPs powered by the electricity from the CFPP, the equivalent CO2 emissions were 43% and 44% lower than directly burning coal with the CFHs but were 46% and 44% higher than the GFHs that burn natural gas. However, when using the GFPP-generated electricity to run the GSHPs, the equivalent CO2 emissions would be 84% and 47% lower than the CFHs and the GFHs, respectively

Aircraft navigation based on differentiation–integration observer

In this paper, a generalized differentiation–integration observer is presented based on sensors selection. The proposed differentiation–integration observer can estimate the multiple integrals and high-order derivatives of a signal, synchronously. The parameters selection rules are presented for the differentiation–integration observer. The theoretical results are confirmed by the frequency–domain analysis. The effectiveness of the proposed observer is verified through the numerical simulations on a quadrotor aircraft: i) through the differentiation–integration observer, the attitude angle and the uncertainties in attitude dynamics are estimated synchronously from the measurements of angular velocity; ii) a control law is designed based on the observers to drive the aircraft to track a reference trajectory

Mitigating Particulate Matter Emissions of a Commercial Cage-free Aviary Hen House

Concerns over animal welfare among general public and marketing decisions have led to pledges by a number of U.S. food retailers and restaurants to source only cage-free (CF) eggs in the foreseeable future, e.g., by 2025. Compared to conventional cage production system, CF hen housing offers hens more space and opportunities to exercise their natural behaviors (e.g., perching, dust bathing, and foraging). However, CF housing poses many inherent environmental challenges, among which are high levels of particulate matter (PM) and ammonia (NH3). Spraying liquid agent (e.g., 125 mL m-2 per cm litter depth) has been shown to effectively mitigate the generation of PM by 60-70% from CF henhouse litter in our previous lab-scale tests. The objectives of this study were to verify the lab-study findings of PM reduction with liquid spray on a commercial CF farm and to evaluate the indoor air and litter quality before and after liquid spray. This field verification study was conducted with a commercial aviary CF house (50,000 laying hens, L×W×H = 154 × 21.3 × 3.0 m) in Iowa during winter of 2017-2018. A water sprinkling system was installed in half of the experimental henhouse in the length direction (treatment section), whereas the other half of the henhouse served as the control. In each trial, the spray dosage (125 mL H2O m-2 per cm litter depth) was adjusted according to the initial litter depth before the spray. A total of three trials were conducted in this study. Results show that the PM concentration was reduced by 37-51% PM in the commercial aviary henhouse. The lower reduction efficiency in the field than the values obtained in the lab tests was partially attributed to the fact that water spray was applied to only the open litter area, and the litter area under the aviary system was not sprayed. Adjusting spray dosage according to litter depth is necessary for maintaining a certain reduction efficiency. Litter moisture content of the treatment sections was 9-14% higher than control (i.e., 15.6% vs. 14% for Trial 1, 14.6% vs. 12.2% for Trial 2, and 17.7% vs. 14.9% for Trial 3), but NH3 concentrations in treatment and control were similar during the test

Particulate Matter Suppression and Heat Stress Relief in a Cage-free Hen House

Compared to conventional cage production system, cage-free (CF) hen housing offers hens more space and opportunities to exercise their natural behaviors (e.g., perching, dust bathing, and foraging). However, CF housing poses many inherent environmental challenges, among which are high levels of particulate matter (PM). Spraying liquid agent (e.g., 125 mL m-2 per cm litter depth) has been shown to effectively mitigate the generation of PM by 60%-70% from CF henhouse litter in our previous lab-scale tests. The objectives of this study were to verify the lab-study findings of PM reduction with liquid spray on a commercial CF farm and to evaluate the cooling effect of liquid spray on hens in hot weather. This study was conducted with a commercial aviary CF house (50,000 laying hens) in Iowa during winter of 2017-2018 and summer of 2018. A water sprinkling system was installed in half of the experimental henhouse in the length direction (treatment section), whereas the other half of the henhouse served as the control. Results show that the PM emission was reduced by 37%-51%. Adjusting spray dosage according to litter depth is necessary for maintaining a certain reduction efficiency. Litter moisture content of the treatment sections was 9%-14% higher relative to the control, but NH3 concentrations in treatment and control were similar. For the summer cooling, sprinkled hens had up to 7 oC lower body surface temperature than non-sprinkled one immediately after a 20-sec or 30 mL m-2 water spray. The sprinkled hens were still 5 oC cooler than the non-sprinkled ones 3 min after spray. The cooling effect for some birds lasted for about 10 min, but most would dry out soon under the testing conditions (temperature of 35 oC and relative humidity of 32%)

Mitigating Particulate Matter Generations in a Commercial Cage-free Henhouse

Compared to conventional cage production systems, cage-free (CF) hen housing offers hens more space and opportunities to exercise their natural behaviors (e.g., perching, dust bathing, and foraging). However, CF housing poses a number of inherent environmental challenges, among which are high levels of particulate matter (PM) and ammonia (NH3). Spraying water on CF henhouse litter (e.g., 125 mL m-2 per cm litter depth) has been shown to mitigate generation of PM by 60-70% in our previous lab-scale tests. The objectives of this study were to verify the lab-study findings of PM reduction in a commercial CF henhouse in central Iowa and to evaluate the indoor air quality (e.g., PM and NH3 concentrations) and litter moisture content affected by water spray. The commercial CF house had a nominal capacity of 50,000 laying hens, measuring L×W×H = 154 × 21.3 × 3.0 m). A water sprinkling system was installed in half of the henhouse in the length direction (treatment section), whereas the other half of the henhouse served as the control. For each of the three trials conducted during winter of 2017-2018, spray dosage (125 mL H2O m-2 per cm litter depth) was set according to the initial litter depth before spray. Results show that PM concentration was reduced by 37-51% PM in the treatment section of the CF henhouse. The lower reduction efficiency in the field than in the lab tests was partially attributed to the fact that water spray in the commercial henhouse was applied to only the open litter area, and not the litter area under the aviary system due to limited space. Adjusting spray dosage according to litter depth is necessary for maintaining the appreciable reduction efficiency. Litter moisture content of the treatment section was 9-14% higher than that of the control (15.6% vs. 14% in Trial 1, 14.6% vs. 12.2% in Trial 2, and 17.7% vs. 14.9% in Trial 3), but NH3 concentrations in the treatment and control sections were similar during the test

Computer Vision-Based Animal Preference Assessment – Do Laying Hen Chicks Prefer Light with UVA Radiation?

Poultry have a fourth retinal cone that allows them to see in the ultraviolet A (UVA) wavelength (315-400 nm) and may use UVA perception to modify various behavioral functions such as feeding, peer recognition, mate selection, and social encounters. As UVA perception is an essential part of poultry vision, it may be of socio-economic significance to provide certain amount of UVA light in poultry production facilities, particularly in most of modern facilities where artificial lighting is the only light source for the birds. However, there is limited scientific information regarding how to provide the UVA supplementation to birds as well as the behavioral responses of birds to UVA radiation. The objective of this study was to assess preference of W-36 chicks (day-old) for light-emitting diode (LED) light supplemented with or without various levels of UVA radiation (0%, 5%, 10%, and 15%), i.e., LED vs. LED+UVA. A total of 108 chicks (day-old) in 18 groups over nine successive batches were assessed for their choice via preference test. For each group (six chicks), each bird was individually identified with one of the six colored marks (yellow, green, blue, purple, pink, and orange) on the head. Each group of chicks involved an 8-day preference test, during which the birds could move freely between two inter-connected compartments that contained LED and LED+UVA, respectively. A real-time monitoring system was employed to record behaviors of chicks at a capture rate of 5 frames per second. Trajectory of each bird was tracked using automated computer vision based on color detection algorithms. Time spent and feed intake by the birds under each light condition were measured daily and analyzed with generalized linear mixed models. The following results were found. In the scenario of 0% vs. 5% UVA, the chicks spent significantly lower amount of time under LED+UVA than under LED (45.6% vs. 54.4%), but had comparable feed use under both light conditions. In the scenario of 0% vs. 10% UVA, the chicks showed similar amount of time spent and feed use. In the scenario of 0% vs. 15% UVA, the chicks spent significantly higher proportion of time (61.3% vs. 38.7%) and consumed significantly more feed (60.5% vs. 39.5%) under LED+UVA than under LED. The study demonstrates the attracting effect of UVA light at 15% inclusion rate under LED illumination on chicks in terms of time spent and feed use. A large-scale and long-term study to further verify the positive effects of UVA inclusion seems warranted

Behavioral and Production Responses of W-36 Chicks to Supplementary UVA Light

UVA (315-400 nm) light perception is an essential part of poultry vision, which may be used to modify behavioral traits of birds such as feeding, peer recognition, and social encounters. The objectives of this study were to assess behavioral and production responses of W-36 chicks reared under LED light with or without various levels of UVA supplementation (0%, 5%, 10%, and 15%), i.e., LED+UVA vs. LED. For behavioral response, a total of 108 chicks (day-old) in 18 groups were assessed for their lighting preference. Each group of chicks was involved an 8-d preference test, during which the birds could move freely between two inter-connected compartments that contained LED and LED+UVA, respectively. For production response, a total of 180 chicks (day-old) in 12 groups were used to assess the effects of the UVA supplementation (5%) on growth performance of chicks. For each batch, two groups were randomly assigned to two compartments, one with LED and the other with LED+UVA. In the scenario of 0% vs. 5% UVA, the chicks spent significantly lower amount of time under LED+UVA than under LED (45.6% vs. 54.4%), but had comparable feed use under both light conditions. In the scenario of 0% vs. 10% UVA, the chicks showed similar amount of time spent and feed use. In the scenario of 0% vs. 15% UVA, the chicks spent significantly higher proportion of time (61.3% vs. 38.7%) and consumed significantly more feed (60.5% vs. 39.5%) under LED+UVA than under LED. Chicks had comparable growing performance under LED and LED+UVA (5%) and no eye pathology was detected at 5% UVA supplementation level. The study demonstrates the attracting effect of UVA light at 15% inclusion rate under LED illumination on chicks in terms of time spent and feed use. A large-scale and long-term study to further verify the positive effects of UVA inclusion seems warranted