NASA’s Mission of Mars is currently in the news, recently helicopter flies on the Red Planet with Perception Rover have flown several times.
Engineer chopper
NASA’s Ingenuity Explain: A helicopter from the US space agency NASA (National Aeronautics and Space Administration) along with his rover also reached Mars. This helicopter named Ingenuity has flown on the Red Planet many times, which is such a big thing for NASA because for the first time a helicopter has taken flight to another world (NASA Ingenuity Briefing). So let us talk in detail about the Ingenuity Helicopter and its performance today.
Some instructions are uploaded before every single flight of the helicopter, which tells what kind of flight it will be. But when it comes to flying, it depends on the helicopter itself how it will perform and in the meantime, flight control algorithms (a problem solving formula or a kind of procedure, which has some rules, including instruction Is called.) Depends on it. Which were developed on Earth before the Ingenuity was sent to Mars (NASA Perseverance and Ingenuity).
Computer simulation is done
NASA has taken this up on its website and said that before making the algorithms, modeling and computer simulation was done in detail to understand how a helicopter would work in the atmosphere of Mars. Computer simulation refers to the process of mathematical modeling that is done to find out the behavior of something on a computer. Testing was done by preparing a Mars-like environment in NASA’s Jet Propulsion Lab. A 25 m long, 7.5 m diameter vacuum chamber was used for this.
But only certain aspects of the environment could be understood through it (NASA Ingenuity Mars Helicopter). But now Ingenuity has really started flying on Mars, after which now it is also helping to know how things can go beyond expectations. Let’s know some important aspects related to the performance of this flight control system on Mars.
Takeoff of Ingenuity
Like other drones, engineeredness is not controlled by changing the rotor speed. Instead, it is controlled exactly as common helicopter controls are. That is, by changing the pitch angle of the blades. Actually, NASA’s environment is something, for which the rotorcraft’s blades have to take a lot of force. That is why the helicopter has been made lighter. Also, its blades have also been given the power to rotate over 2500 revolutions per minute. That is, how fast the blade can fly according to the wind speed.
When the engine takes off, the rotor is already rotating at a speed of 2,537 rpm. NASA’s team takeoff the helicopter by simultaneously increasing the control on both rotors, causing it to lift off the ground (NASA Ingenuity Helicopter Flight). At this early stage of takeoff, NASA only takes into account the response of the angular rates (ie how fast the helicopter rotates) and limits the control system to respond in other ways.
Sensors get information about movements
But as soon as the helicopter rises 5 cm above, the system is in a position to fully control the position, velocity and attitude of the helicopter. After this, it moves upwards of one meter per second. Sensors are used to detect the movements of the helicopter during the flight, including a rangefinder and a camera (NASA Ingenuity First Flight). The sensor is not used until the helicopter flies up to a meter high because there is a risk of dust from being on the surface.
Therefore, the NASA team uses the Inertial Measurement Unit (IMU) to measure acceleration (rate of change of velocity) and angular rates. Then all these are used to find out his movements. Data from the first three flights of the helicopter shows that it has been in the air for 0.25 seconds, which is in line with NASA’s expectations. NASA expected the required power of the rotor system to increase, as seen later.
For example, the second flight saw an increase of 310 watts, which is less than the maximum capacity of 510 watts of the battery. After takeoff, it took two seconds for the helicopter to reach a height of one meter. Where it started using its sensors. The Percussion Rover was also present near the helicopter where the flight was taking place, dust was visible in some of the pictures taken by him but there was no indication that the dust had blurred the camera lens, which was OK fine. When the helicopter rises above the earth, its speed starts to be affected by the wind.
What is special in hover
Whenever the helicopter hovers, that is, circling the air, NASA tries to maintain its constant height and position. How successful the team is in doing this is all left to the engineer’s own guess as to how he is performing. These same estimates help to know how well it is being controlled. Data shows that the hover is well placed within about one cm. Perceived Rover also has a MEDA (Mars Environmental Dynamics Analyzer) weather station.
Which shows the wind speed, temperature and humidity on Mars. Apart from this, it also shows the dust particles present there and their quantity. With the help of this, all the information is collected and then using this information we find out the performance of the system. That is, how and how much control he has to control during the flight of the helicopter. NASA says that during the first flight of the helicopter the hover was hovering around 9.2 degrees on the lower rotor, with 8.2 degrees on the upper rotor.
Evaluation of psychic control
NASA says that whatever was thought about the hover, it has been found to meet some of the same expectations. All the results showed that there is a good margin against ‘aerodynamic stall’ (NASA Ingenuity Design). Aerodynamic stall – Stall is a state of aerodynamics or aviation, whereby the folding angle of attack (the angle at which the air cord of an aircraft’s wings meet at a speed of air) starts to increase at a certain point.
Along with this, its psychic control was also evaluated, which is responsible for the pitch and roll. That is, how does the helicopter move up and down while flying. Hover has also seen relatively stable values, typically less than 3 degrees (NASA Ingenuity Helicopter Team). Psychic control also provides information about the wind, against which the concerned vehicle has to fly.
Helicopter landing
Landing is a challenging part for any flight. The engine lands after flying directly from the earth, after which the touchdown is detected again. But many incidents happen rapidly, such as a touchdown. First the descent rate (the vertical component of the vehicle’s velocity) is stabilized by 1 meter per second. When the aircraft’s feet are at a height of one meter from the ground, the algorithm stops using the navigation camera and altimeter to make estimates. It seems to depend entirely on the IMU. Doing this during takeoff avoids dusting.
Another purpose of this is to estimate velocity easily. Which is important to avoid touching the surface prematurely i.e. touchdown. Touchdown detection is detected only after half a second of turning on the IMU, when the vehicle’s foot is estimated to be 0.5 meters above the ground. Ingenuity is a touchdown when the descent velocity (the speed with which an object moves in a direction) falls by 25 cm or more per second.
What happens in the last step?
As soon as the engine comes to the surface, the descent velocity also falls rapidly. The flight control system then stops trying to control the speed of the helicopter (NASA and Ingenuity). The system then waits until the helicopter is on the surface for about 3 seconds. After which the speed of its rotor is reduced. A question also arises as to why NASA makes contact with the ground at a relatively high speed of 1 meter per second.
There are many reasons for this. First of all, it reduces the dead-reckoning time, which needs to be spent without a camera and an altimeter. Second, it reduces the time it takes for the ‘ground effect’, where there is less information about the dynamics of the vehicle. Third, it makes it easy to find that we have come to the surface. All this has been successful due to the landing gear design, which prevents the aircraft from faltering at the time of landing.
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