aircraft:tmd:rigidbody
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| For this mathematical description Aerofly needs to know a few key parameters of the objects it is simulating. Most important of all is the **mass**, which is represented in Kilograms. The mass defines how fast an object accelerates when a given force acts onto it. For example: If an aircraft is on the ground and the aerodynamic forces are neglitable then the acceleration of the aircraft is directly proportional to the thrust of the engine divided by the mass of the aircraft. Heavier aircraft with the same thrust will therefor accelerate much slower than light aircraft. And only if the total mass of the aircraft is set to a realistic value will the acceleration be realistic. | For this mathematical description Aerofly needs to know a few key parameters of the objects it is simulating. Most important of all is the **mass**, which is represented in Kilograms. The mass defines how fast an object accelerates when a given force acts onto it. For example: If an aircraft is on the ground and the aerodynamic forces are neglitable then the acceleration of the aircraft is directly proportional to the thrust of the engine divided by the mass of the aircraft. Heavier aircraft with the same thrust will therefor accelerate much slower than light aircraft. And only if the total mass of the aircraft is set to a realistic value will the acceleration be realistic. | ||
| - | ==== Rigidbody ===== | + | Here is a visualization of how all the rigidbodies of the DR400 aircraft: |
| + | {{ : | ||
| + | |||
| + | ===== Rigidbody | ||
| Aerofly uses the mathematical concept of a rigidbody to simulate the aircraft mass. A rigidbody in Aerofly can be thought of as a box with a certain size, a certain mass, position and orientation, | Aerofly uses the mathematical concept of a rigidbody to simulate the aircraft mass. A rigidbody in Aerofly can be thought of as a box with a certain size, a certain mass, position and orientation, | ||
| We usually break down the aircraft into several parts, for example the left and right wings, the fuselage, stabilizer, propeller and individual parts of the landing gear (those that move independent of each other). | We usually break down the aircraft into several parts, for example the left and right wings, the fuselage, stabilizer, propeller and individual parts of the landing gear (those that move independent of each other). | ||
| - | |||
| - | Here is a visualization of how all the rigidbodies of the DR400 aircraft: | ||
| - | {{ : | ||
| - | |||
| In the [[aircraft: | In the [[aircraft: | ||
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| In the Aerofly FS 2 physics engine we have several joint types to chose from: | In the Aerofly FS 2 physics engine we have several joint types to chose from: | ||
| - | * multibody_joint | + | |
| - | * jointlinear | + | |
| - | * jointtorque | + | |
| ==== Multibody-Joint ==== | ==== Multibody-Joint ==== | ||
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| A '' | A '' | ||
| - | This is an example of the left wing's root joint. It is allows a rotation around the x-axis, which means the wing can still flap up and down but it can't freely move forward, left/right or up/down (without rotation) relative to the fuselage or rotate around any other axis. | + | This joint is widely used in Aerofly FS 2, it constrains the movements of each part so that long chains like the actuated landing gear of an airliner become relatively easy to understand and set up and compute but still allowing complex movement. For example: The landing gear is rotated around one axis when it is retracted. But the lower part of the landing gear is not directly attached, it has a damper that dampens most of the shock when the aircraft touches down. |
| + | |||
| + | This is an example of the left wing's root joint. It is allows a rotation around the x-axis, which means the wing can still flap up and down but it can't freely move forward, left/right or up/down (without rotation) relative to the fuselage or rotate around any other axis. The values Kp and Kd are set quite high, since the wing creates a lot of lift and this joint has to transfer that bending torque around the root. It's a stiff connection that doesn' | ||
| + | |||
| + | > **Caution**: | ||
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| === Kd === | === Kd === | ||
| - | Damping constant in Newton-Meter per radiant | + | Damping constant in Newton-Meter per radiant |
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| + | ==== Joint-Linear ==== | ||
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| + | Allows full 6 degrees of motion: 3 translation components and 3 rotational components. | ||
| + | |||
| + | == Typical short version === | ||
| + | > **Caution**: | ||
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| + | == Full version === | ||
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| + | > **Caution**: | ||
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| + | ></ | ||
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| + | === Rigid == | ||
| + | Setting '' | ||
| + | |||
| + | === R0 === | ||
| + | |||
| + | '' | ||
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| + | === X0, Y0, Z0 === | ||
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| + | X0, Y0 and Z0 define a rotation matrix to rotate the joint' | ||
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| + | === Kf, Kt == | ||
| + | All '' | ||
| + | '' | ||
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| + | === Df == | ||
| + | All '' | ||
| + | '' | ||
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| + | === ForceMax, TorqueMax === | ||
| + | Defines the force and torque at which the connection breaks. From that moment on the two bodies are completely independant and the crash reset timer is started which reloads the aircraft after (default) 3 seconds. | ||
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| + | === Rotation Input === | ||
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| + | Using Rotation0Control, | ||
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| + | === PreLoad, PreTension === | ||
| + | Defines the offset force (in Newtons) or torque (in Newton-Meters). When the deflection or displacement is zero this force or torque is still acting between the two bodies. Normally the landing gear would compress under the weight of the aircraft but the PreLoad parameter could reduce this displacement to zero on the ground. In the air the gear would then extend outward. | ||
| + | ==== Joint-Torque ==== | ||
| + | |||
| + | Only applies a torque between two bodies and doesn' | ||
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| + | > **Caution**: | ||
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| + | ></ | ||
aircraft/tmd/rigidbody.1538304783.txt.gz · Last modified: 2018/09/30 12:53 by jh