Documentation

Unicycle Kinematic Model

Compute vehicle motion using unicycle kinematic model

• Library:
• Robotics System Toolbox / Mobile Robot Algorithms Description

The Unicycle Kinematic Model block creates a unicycle vehicle model to simulate simplified car-like vehicle dynamics. This model approximates a vehicle as a unicycle with a given wheel radius, Wheel radius, that can spin in place according to a steering angular velocity, ω.

Ports

Input

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Angular velocity of the wheel in radians per second.

Dependencies

To enable this port, set the Vehicle inputs parameter to Wheel Speed & Heading Angular Velocity.

Vehicle speed, specified in meters per second.

Dependencies

To enable this port, set the Vehicle inputs parameter to Vehicle Speed & Heading Angular Velocity.

Angular velocity of the vehicle, specified in radians per second. A positive value steers the vehicle left and negative values steer the vehicle right.

Output

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Current xy-position and orientation of the vehicle, specified as a [x y theta] vector in meters and radians.

The linear and angular velocities of the vehicle, specified as a [xDot yDot thetaDot] vector in meters per second and radians per second. The linear and angular velocities are calculated by taking the derivative of the state output.

Parameters

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Type of speed and directional inputs to control the vehicle. Options are:

• Vehicle Speed & Heading Angular Velocity — Vehicle speed in meters per second with a heading angular velocity in radians per second..

• Wheel Speed & Heading Angular Velocity — Wheel speed in radians per second with a heading angular velocity in radians per second.

The wheel radius of the vehicle, specified in meters.

The minimum and maximum wheel speeds, specified in radians per second.

The initial x-, y-position and orientation, theta, of the vehicle.

• Interpreted execution — Simulate model using the MATLAB® interpreter. For more information, see Simulation Modes (Simulink).

• Code generation — Simulate model using generated C code. The first time you run a simulation, Simulink® generates C code for the block. The C code is reused for subsequent simulations, as long as the model does not change.

Tunable: No

 Lynch, Kevin M., and Frank C. Park. Modern Robotics: Mechanics, Planning, and Control 1st ed. Cambridge, MA: Cambridge University Press, 2017.

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