Outdoor obstacle detection using ultrasonic sensors for an autonomous vehicle ensuring safe operations

Ultrasonic or sonar sensors are widely used for range finding for indoor and outdoor applications in robotics. However, for outdoors applications, they pose different environmental challenges. Ultrasonic sensor can be used both in air and underwater. It emits acoustic pulses in a cone shaped form in its surroundings and waits for the echoes from the objects nearby that lie within its working range. Ultrasonic sensors have convincing advantages over other sensors. However, sonar sensors have different practical limitations as well which need to be carefully dealt with while working with these sensors. Ultrasonic sensors have several applications in electronics and robotics including obstacle detection and avoidance, mapping and navigation, object recognition and identification. Ultrasonic sensors are widely used in automatic car parking systems in modern vehicles, where two to four sensors are mounted in rear bumper for detecting obstacles up to 2.5 meter and assisting the driver about the parallel parking. The thesis is mainly divided into two parts. In the first part, background studies and literature review is presented which describes sonar sensing principle, applications, advantages, limitations and outdoor sensing challenges. In the second part, a sonar system for obstacle detection for a mobile machine is implemented and its tests and results are discussed. The study indicates the testing of ultrasonic sensors for obstacles detection for an autonomous mobile vehicle outdoor. The sensors were tested both on static frame and on real machine detecting different obstacles from 60 cm up to five meters. The results are better when the object is in front or moving along the axis of the sensor. The sensors are connected in series and are in ranging mode all the time. The experimental results show that the environmental factors like, air turbulence and temperature change affect the speed of sound in air and measuring range. The ranging value is better indoors than the outdoors for same obstacles. However, the results are better on less windy day and also when the surface is strong reflector. It is noted that the results get improved when a cone made of paper or plastic is wrapped around the transducer. The sensor is protected with a water proof casing made of PVC plastic material and it is noted that the casing made of aluminum does not yield good results as compared with the plastic casing. The two or more sensors attached in line increase the covering area of the system

Design Fabrication & Real Time Vision Based Control of Gaming Board

This paper presents design, fabrication and real time vision based control of a two degree of freedom (d.o.f) robot capable of playing a carom board game. The system consists of three main components: (a) a high resolution digital camera (b) a main processing and controlling unit (c) a robot with two servo motors and striking mechanism. The camera captures the image of arena and transmits it to central processing unit. CPU processes the image and congregate useful information using adaptive histogram technique. Congregated information about the coordinates of the object is then sent to the RISC architecture based microcontroller by serial interface. Microcontroller implements inverse kinematics algorithms and PID control on motors with feedback from high resolution quadrature encoders to reach at the desired coordinates and angles. The striking unit exerts a controlled force on the striker when it is in-line with the disk and carom hole (or, pocket). The striker strikes with the disk and pots (to hit (a ball) into a pocket) it in the pocket. The objective is to develop an intelligent, cost effective and user friendly system that fulfil the idea of technology for entertainment

Outdoor obstacle detection using ultrasonic sensors for an autonomous vehicle ensuring safe operations

Ultrasonic or sonar sensors are widely used for range finding for indoor and outdoor applications in robotics. However, for outdoors applications, they pose different environmental challenges. Ultrasonic sensor can be used both in air and underwater. It emits acoustic pulses in a cone shaped form in its surroundings and waits for the echoes from the objects nearby that lie within its working range. Ultrasonic sensors have convincing advantages over other sensors. However, sonar sensors have different practical limitations as well which need to be carefully dealt with while working with these sensors. Ultrasonic sensors have several applications in electronics and robotics including obstacle detection and avoidance, mapping and navigation, object recognition and identification. Ultrasonic sensors are widely used in automatic car parking systems in modern vehicles, where two to four sensors are mounted in rear bumper for detecting obstacles up to 2.5 meter and assisting the driver about the parallel parking. The thesis is mainly divided into two parts. In the first part, background studies and literature review is presented which describes sonar sensing principle, applications, advantages, limitations and outdoor sensing challenges. In the second part, a sonar system for obstacle detection for a mobile machine is implemented and its tests and results are discussed. The study indicates the testing of ultrasonic sensors for obstacles detection for an autonomous mobile vehicle outdoor. The sensors were tested both on static frame and on real machine detecting different obstacles from 60 cm up to five meters. The results are better when the object is in front or moving along the axis of the sensor. The sensors are connected in series and are in ranging mode all the time. The experimental results show that the environmental factors like, air turbulence and temperature change affect the speed of sound in air and measuring range. The ranging value is better indoors than the outdoors for same obstacles. However, the results are better on less windy day and also when the surface is strong reflector. It is noted that the results get improved when a cone made of paper or plastic is wrapped around the transducer. The sensor is protected with a water proof casing made of PVC plastic material and it is noted that the casing made of aluminum does not yield good results as compared with the plastic casing. The two or more sensors attached in line increase the covering area of the system

Regional climate assessment of precipitation and temperature in Southern Punjab (Pakistan) using SimCLIM climate model for different temporal scales

Unbalanced climate during the last decades has created spatially alarming and destructive situations in the world. Anomalies in temperature and precipitation enhance the risks for crop production in large agricultural region (especially the Southern Punjab) of Pakistan. Detailed analysis of historic weather data (1980–2011) record helped in creating baseline data to compare with model projection (SimCLIM) for regional level. Ensemble of 40 GCMs used for climatic projections with greenhouse gas (GHG) representative concentration pathways (RCP-4.5, 6.0, 8.5) was selected on the baseline comparison and used for 2025 and 2050 climate projection. Precipitation projected by ensemble and regional weather observatory at baseline showed highly unpredictable nature while both temperature extremes showed 95 % confidence level on a monthly projection. Percentage change in precipitation projected by model with RCP-4.5, RCP-6.0, and RCP-8.5 showed uncertainty 3.3 to 5.6 %, 2.9 to 5.2 %, and 3.6 to 7.9 % for 2025 and 2050, respectively. Percentage change of minimum temperature from base temperature showed that 5.1, 4.7, and 5.8 % for 2025 and 9.0, 8.1, and 12.0 % increase for projection year 2050 with RCP-4.5, 6.0, and 8.5 and maximum temperature 2.7, 2.5, and 3.0 % for 2025 and 4.7, 4.4, and 6.4 % for 2050 will be increased with RCP-4.5, 6.0, and 8.5, respectively. Uneven increase in precipitation and asymmetric increase in temperature extremes in future would also increase the risk associated with management of climatic uncertainties. Future climate projection will enable us for better risk management decisions

SARS-CoV-2 vaccination modelling for safe surgery to save lives: data from an international prospective cohort study

Background: Preoperative SARS-CoV-2 vaccination could support safer elective surgery. Vaccine numbers are limited so this study aimed to inform their prioritization by modelling. Methods: The primary outcome was the number needed to vaccinate (NNV) to prevent one COVID-19-related death in 1 year. NNVs were based on postoperative SARS-CoV-2 rates and mortality in an international cohort study (surgical patients), and community SARS-CoV-2 incidence and case fatality data (general population). NNV estimates were stratified by age (18-49, 50-69, 70 or more years) and type of surgery. Best- and worst-case scenarios were used to describe uncertainty. Results: NNVs were more favourable in surgical patients than the general population. The most favourable NNVs were in patients aged 70 years or more needing cancer surgery (351; best case 196, worst case 816) or non-cancer surgery (733; best case 407, worst case 1664). Both exceeded the NNV in the general population (1840; best case 1196, worst case 3066). NNVs for surgical patients remained favourable at a range of SARS-CoV-2 incidence rates in sensitivity analysis modelling. Globally, prioritizing preoperative vaccination of patients needing elective surgery ahead of the general population could prevent an additional 58 687 (best case 115 007, worst case 20 177) COVID-19-related deaths in 1 year. Conclusion: As global roll out of SARS-CoV-2 vaccination proceeds, patients needing elective surgery should be prioritized ahead of the general population