Fire rescue operations can be very demanding and dangerous to the people and equipment involved. Through the use of an unmanned aerial vehicles fire rescue personnel have the potential to utilize a valuable tool that allows them a birds eye view of the rescue scene. Thermal imaging allows for identification of hot spots within structure and locating people within burning buildings and homes. Such a technology becomes more critical when responding at night in the dark where visibility is limited.
The UAS must withstand various weather conditions, high temperatures, and supporting a variety of sensor payloads. Below are sample base requirements for the system and their respective derived requirements.
Air Vehicle system development design considerations cover such areas as maximum altitude, cruise speed, loiter speed, climb rate, radius of action, and hover capability. One of the key requirements needed by fire rescue personnel is the ability to circle or lock onto an object or structure and either orbit or hover to provide real time visual feedback.
1. Air Vehicle Element
1.1. Shall provide capability to orbit (i.e., fly in circular pattern around) or hover over an object of interest.
1.1.1. [Derived] Air Vehicle shall avoid obstacles when circling around object of interest
1.1.2. [Derived] Air Vehicle orbit radius shall be modifiable based on location.
1.1.3. [Derived] Air Vehicle hover altitude shall be modifiable based on location.
1.1.4. [Derived] Air Vehicle orbit shall automatically compensate for high temperatures above maximum threshold.
1.1.5. [Derived] Air Vehicle hover shall automatically compensate for high temperatures above maximum threshold.
1.1.6. [Derived] Air Vehicle orbit shall hold hover accuracy within twelve inches when winds reach up to 25 mph.
1.1.7. [Derived] Air Vehicle orbit shall hold hover accuracy within twelve inches when winds reach up to 25 mph.
Command and control is a critical interface needed for the receipt, processing, and transmission of information. Visual feedback requirements are critical to help with rescue decisions based on endangered life found within burning structure as well as hot spots that can’t be identified other than thermal imaging.
2. Command and Control (C2)
2.1. Shall visually depict payload sensor views
2.1.1. [Derived] C2 shall display high definition (720P) color live video feed when mode is selected.
2.1.2. [Derived] C2 shall display thermal imaging to identify hot spots versus life when mode is selected.
2.1.3. [Derived] C2 shall display sensor views on rugged Toughbook laptop.
2.1.4. [Derived] C2 Human machine interface for payload sensor views shall be designed per current human factors standards
The payload determines the capability of the vehicle and mission type. Modularity of payloads is a major advantage allowing for greater versatility and environments. Size, weight, power consumption, and cost are key payload characteristics that need to be taken into consideration during system development.
3. Payload
3.1. Shall use power provided by air vehicle element
3.1.1. [Derived] Payload shall be provided power by the air vehicle for up to 2 hours.
3.1.2. [Derived] Payload shall notify/communicate to operator when power requirements are at a minimum due to system issue.
3.1.3. [Derived] Payload air vehicle power should have a back up redundant system so landing is not required for troubleshooting.
Data link communications involves range, missions, deployment area, availability of frequencies, and operational cost. The radius of action of the air vehicle is an import factor contributing to the usefulness of the system being developed. Determining whether the system will be flown within line of sight or beyond line of sight must be known early on in the system development.
4. Data-Link
4.1. Shall be capable of communication range exceeding two miles visual line of site (VLOS).
4.1.1. [Derived] Data-Link shall be impermeable to radio signal interference when beyond line of sight.
4.1.2. [Derived] Data-Link uplink/downlink signal shall not degrade when at a distance of two miles.
4.1.3. [Derived] Data-Link shall operator on a standard frequency that is secure.
Testing requirements are required to verify the derived requirements are met or exceeded.
5. Testing Requirements
5.1. Air Vehicle
5.1.1. Performance Accuracy
5.1.1.1. Verify hover capability minimum position requirement is met
5.1.1.2. Verify orbit capability minimum position requirement is met
5.1.1.3. Verify when position modification is made during orbit vehicle adjusts accordingly
5.1.1.4. Verify vehicle adjusts orbit when maximum temperature is reached
5.1.1.5. Verify vehicle adjusts hover when maximum temperature is reached
5.2. Command and Control
5.2.1. Reliability
5.2.1.1. Verify high definition video feed functions during flight without signal loss
5.2.1.2. Verify thermal imaging video mode functions properly during flight.
5.2.1.3. Verify C2 communication and interface between Toughbook and air vehicle
5.2.1.4. Verify HMI is user friendly and intuitive for operator.
5.3. Payload
5.3.1. Functionality
5.3.1.1. Verify maximum power requirements of air vehicle during flight
5.3.1.2. Verify minimum power requirements of air vehicle during flight.
5.3.1.3. Verify redundant back up system functions when air vehicle power can not supply payload power
5.3.1.4. Verify user message/alarm when power reduction/failure occurs.
5.4. Data Link
5.4.1. Reliability
5.4.1.1. Test air vehicle communication using standard forms of radio interference to verify system is not compromised
5.4.1.2. Test flight of air vehicle at pre-determined distance intervals to meet communication requirements when beyond line of sight.
The system development sample requirements outlined above would require the 10-phase waterfall method, which would start with the concept design and research leading to design, test, development, certification, production, and support. The purpose of using this method is due to tight control of requirements, documentation, and formal gate reviews. The system development methodology also allows for tight control of schedule and cost. The fire rescue drone would use common off the shelf components allowing for the budget to be met within the nine month scheduled project. Ground testing would also involve component and subsystem testing due to the harsh environments the vehicle would encounter. Temperature, wear, functionality, strength, fatigue, and acceleration are all key characteristic that would require baseline data. Subsystem testing would require verification of the flight control system, power plant, and payloads under simulated flight conditions at a minimum.
References:
Austin, R. (2010). Unmanned aircraft systems: UAVS design, development, and deployment. Chichester, West Sussex, U.K: Wiley.
AndyGurd. (2013, January 28). Managing your requirements 101 –A refresher. Part 4: What is traceability? [Web log post]. Retrieved from https://www.ibm.com/developerworks/community/blogs/requirementsmanagement/entry/managing_your_requirements_101_a_refresher_part_4_what_is_traceability7?lang=en
No comments:
Post a Comment