![]() At this point we’re accelerating toward a vertical climb rate of 1 meter per second. The initial takeoff phase lasts for only a split second once the helicopter has climbed a mere 5 centimeters, the system asserts full control over the helicopter’s position, velocity, and attitude. The reason for this is that we don’t want the control system to be fighting against the ground, possibly resulting in undefined behavior. During this initial takeoff phase, we limit the control system to respond only to angular rates (how quickly the helicopter rotates or tilts). We take off with a sudden increase in collective control on both rotors, which causes the vehicle to “boost” off the ground. ![]() When Ingenuity takes off, the rotor is already spinning at the setpoint speed of 2,537 rpm. Like a traditional helicopter, we can change the pitch angle in two ways: by using “collective control,” which changes the blade pitch uniformly over the entire rotation of the blade, and by using “cyclic control,” which pitches the blade up on one side of the vehicle and down on the other. The bigger the bite, the more lift (and drag) is produced. Instead, we control our Mars Helicopter in the same manner as full-scale terrestrial helicopters: by changing the pitch angle of the blades, which affects the airfoil “angle of attack” and thereby determines how big a “bite” the blades take out of the air. ![]() Unlike many consumer drones, Ingenuity is not controlled by changing the rotor speeds. Here are some key aspects of the flight control system’s performance on Mars. Now that Ingenuity is actually flying at Mars, we can begin to assess how things stack up against expectations. But in all of that work, we could only approximate certain aspects of the environment. We followed that up with testing in a massive 25-meter-tall, 7.5-meter-diameter vacuum chamber here at JPL where we replicate the Martian atmosphere. To develop those algorithms, we performed detailed modeling and computer simulation in order to understand how a helicopter would behave in a Martian environment. But when it comes time to fly, the helicopter is on its own and relies on a set of flight control algorithms that we developed here on Earth before Ingenuity was even launched to Mars. ![]() Before each of Ingenuity’s test flights, we upload instructions that describe precisely what the flight should look like. ![]()
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