Unicycle Kinematic Model

Compute vehicle motion using unicycle kinematic model

expand all in page
  • Library:

  • Robotics System Toolbox / Mobile Robot Algorithms

  • Unicycle Kinematic Model block

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

expand all

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

expand all

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

expand all

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

Model Examples

Plan Path for a Unicycle Robot in Simulink

Plan Path for a Unicycle Robot in Simulink

Demonstrates how to execute an obstacle-free path between two locations on a given map in Simulink®. The path is generated using a probabilistic road map (PRM) planning algorithm (mobileRobotPRM). Control commands for navigating this path are generated using the Pure Pursuit controller block. A unicycle kinematic motion model simulates the robot motion based on those commands.

References

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

Extended Capabilities

C/C++ Code Generation
Generate C and C++ code using Simulink® Coder™.

See Also

Blocks

Classes

Introduced in R2019b

Robotics System Toolbox Documentation

Support