The Portland fire department contacted you for a consultation. The Fire departme
ID: 1766419 • Letter: T
Question
The Portland fire department contacted you for a consultation. The Fire department along with the Oregon department of forestry (ODF) initiated a program to use Drone in case of forest fire in remote areas to speed up the response time. They want to develop a special drone, which can provide continuous coverage of live video surveillance by hovering above the forest fire area. High temperature and strong wind conditions are the expected challenges. The Fire department had no idea how to develop a Drone suitable to the expected conditions. Obviously they tried some of the commercially available Drones (mostly consumer drones) but all failed. They cannot even find the failed drones because they all fall into the testing forest fire location.
(a) What factors do you think caused the severe damage to the Drones the department tested? (other than the gusty wind) and what damage can cause malfunction of the camera attached to the drone, which is a crucial part for operation?
The department Chief was convinced by your explanation and decided to provide funding to you to develop a Drone, which can fit their need. Assume you found a good vendor making stable Drone structure and body, which can withstand the heat beyond the expected lifetime. But the camera module vendor is hard to find. One vendor proposed that their camera module can withstand the high temperature and show their testing data. From the Weibull plot the vendor provided,
(b) What is the characteristic life time?
(c) What is the time until the 1% failure rate?
(d) How many samples did the vendor tested to get this weibull plot? You can see there are 11 failed samples but what is the total number of the tested sample? (use the following equation)
F(t) = (i - 0.3)/(n + 0.4)
(e) Regarding the first failure in the weibull plot. Do you think the data point is valid? Or do you want to eliminate the data point? And Why?
(f) If you eliminate the first failure data point, how will the characteristic life time change?
99.00 C 50.00 10.00 1.00 10.00 100.00 1000.00 10000.00 Time to Failure (h)Explanation / Answer
(A) The various factors that contribute to the damage of the drones are:-
(1) High temperature zones of the forest fire which could damage the electronics of the drone and cause malfunctioning to its operation.
(2) Due to hasty winds, the turbulence around the drone poses a major cause of malfunction. this could lead to crashing of the drone directly into the fire area. This makes the drone to go in the direction where it does not want to go. For this the high power motor is required to carry out the desired objective.
(3) Motor failure is also a cause of loss of funtionality in drone.
(4) Due to fire the birds that fly around can potentially collide with the drone causing loss of functionality.
(5) The camera could malfunction in the situation when the work for extingushing fire will start. The vapors of the waters can be condensed onto the lens of the camera which would depriciate the quality of video. Similarly fog, dew and temerature variation are potential contributors towards the functionality of camera.
(B) The chrecterictic life time for camera is approximately 100 to 1000 hrs as the percentage failure rate is increased significantly as we take a close look at the data points available.
(C) Approximately 90 hours is the time ultill 1% failure rate.
(E) The 1st failure rate data point can be a faulty data point as it is so uneven from the distribution trend line as shown in the graph. So it is justified to neglect this data point to have a better understanding of the problem.
(F) If the 1st data point is neglected the charecteristic life expectancy would be approximately 600 to 1000 hours, which seems to be justified with the trend of percentage failure rate.
Related Questions
drjack9650@gmail.com
Navigate
Integrity-first tutoring: explanations and feedback only — we do not complete graded work. Learn more.