Wheel and Axle
Wheel and axle.
Description
The Wheel and Axle block represents the wheel and axle mechanism shown in the following diagram.
The wheel and axle are coaxial, and it is assumed that the axle is rigidly connected to the frame, making this mechanism an ideal converter of mechanical rotary motion into mechanical translational motion. The mechanism has two connections: a mechanical rotational port A corresponding to the axle, and a mechanical translational port P corresponding to a point on the wheel rim. The mechanism is described by the following equations:
Where:
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- torque on the axle.
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- the force on the wheel rim.
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- angular velocity of the wheel.
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- linear velocity at the wheel rim.
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- wheel radius.
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- orientation of the mechanism. The value is
+1if rotation of the axis in the globally specified positive direction is converted to translational motion in the positive direction, and-1if positive rotation results in translational motion in the negative direction.
Use the block when modelling rack and pinion gears, steering wheels, lifting devices, winches, etc.
The positive directions of the block are from A to the reference point and from the reference point to P.
Ports
A - axis
`rotational mechanics
Mechanical rotational port, corresponds to the axis.
P is the periphery of the wheel
` translational mechanics'.
Mechanical progressive port, corresponds to a point on the rim of the wheel.
Parameters
Wheel radius - wheel radius
`0.05 m (by default)
Wheel radius.
Mechanism orientation - relationship between axis rotation and translational motion direction
Drives in positive direction (by default)| Drives in negative direction.
The value Drives in positive direction means that axis rotation in the globally assigned positive direction is converted to forward motion in the positive direction. The value Drives in negative direction means that axis rotation in the globally assigned positive direction is converted to forward motion in the negative direction.