83 lines
2.5 KiB
C++
83 lines
2.5 KiB
C++
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#ifndef _GEAR_HPP
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#define _GEAR_HPP
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namespace yasim {
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class RigidBody;
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// A landing gear has the following parameters:
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//
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// position: a point in the aircraft's local coordinate system where the
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// fully-extended wheel will be found.
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// compression: a vector from position where a fully-compressed wheel
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// will be, also in aircraft-local coordinates.
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// spring coefficient: force coefficient along the compression axis, in
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// Newtons per meter.
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// damping coefficient: force per compression speed, in Ns/m
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// static coefficient of friction: force along the ground plane exerted
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// by a motionless wheel. A unitless scalar.
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// dynamic coefficient of friction: force along the ground plane exerted
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// by a sliding/skidding wheel.
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// braking fraction: fraction of the dynamic friction that will be
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// actually exerted by a rolling wheel
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// rotation: the angle from "forward" by which the wheel is rotated
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// around its compression axis. In radians.
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//
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class Gear {
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public:
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Gear();
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// Externally set values
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void setPosition(float* position);
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void setCompression(float* compression);
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void setSpring(float spring);
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void setDamping(float damping);
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void setStaticFriction(float sfric);
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void setDynamicFriction(float dfric);
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void setBrake(float brake);
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void setRotation(float rotation);
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void setExtension(float extension);
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void getPosition(float* out);
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void getCompression(float* out);
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float getSpring();
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float getDamping();
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float getStaticFriction();
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float getDynamicFriction();
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float getBrake();
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float getRotation();
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float getExtension();
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// Takes a velocity of the aircraft relative to ground, a rotation
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// vector, and a ground plane (all specified in local coordinates)
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// and make a force and point of application (i.e. ground contact)
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// available via getForce().
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void calcForce(RigidBody* body, float* v, float* rot, float* ground);
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// Computed values: total force, weight-on-wheels (force normal to
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// ground) and compression fraction.
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void getForce(float* force, float* contact);
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float getWoW();
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float getCompressFraction();
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private:
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float calcFriction(float wgt, float v);
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float _pos[3];
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float _cmpr[3];
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float _spring;
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float _damp;
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float _sfric;
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float _dfric;
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float _brake;
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float _rot;
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float _extension;
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float _force[3];
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float _contact[3];
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float _wow;
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float _frac;
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};
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}; // namespace yasim
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#endif // _GEAR_HPP
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