Plan Path for a Bicycle Robot in Simulink

This example 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 bicycle kinematic motion model simulates the robot motion based on those commands.

Enter start and goal locations

startLoc = [5 5];
goalLoc = [12 3];

The imported maps are : simpleMap, complexMap and ternaryMap.

Model Overview

The model is composed of four primary operations :

• Planning

• Control

• Plant Model

Planning

The Planner MATLAB® function block uses the mobileRobotPRM path planner and takes a start location, goal location, and map as inputs. The blocks outputs an array of wapoints that the robot follows. The planned waypoints are used downstream by the Pure Pursuit controller block.

Pure Pursuit

The Pure Pursuit controller block generates the linear velocity and angular velocity commands based on the waypoints and the current pose of the robot.

Check if Goal is Reached

The Check Distance to Goal subsystem calculates the current distance to the goal and if it is within a threshold, the simulation stops.

Plant Model

The Bicycle Kinematic Model block creates a vehicle model to simulate simplified vehicle kinematics. The block takes linear and angular velocities as command inputs from the Pure Pursuit controller block, and outputs the current position and velocity states.

Run the Model

To simulate the model

Visualize The Motion of Robot

To see the poses :

map = binaryOccupancyMap(simpleMap)
map =
binaryOccupancyMap with properties:

mapLayer Properties
LayerName: 'binaryLayer'
DataType: 'logical'
DefaultValue: 0
GridLocationInWorld: [0 0]
GridOriginInLocal: [0 0]
LocalOriginInWorld: [0 0]
Resolution: 1
GridSize: [26 27]
XLocalLimits: [0 27]
YLocalLimits: [0 26]
XWorldLimits: [0 27]
YWorldLimits: [0 26]

robotPose = simulation.BicyclePose
robotPose = 362×3

5.0000    5.0000         0
5.0001    5.0000   -0.0002
5.0007    5.0000   -0.0012
5.0036    5.0000   -0.0062
5.0181    4.9997   -0.0313
5.0902    4.9929   -0.1569
5.4081    4.8311   -0.7849
5.5189    4.6758   -1.1170
5.5366    4.6356   -1.1930
5.5512    4.5942   -1.2684
⋮

numRobots = size(robotPose, 2) / 3;
thetaIdx = 3;

% Translation
xyz = robotPose;
xyz(:, thetaIdx) = 0;

% Rotation in XYZ euler angles
theta = robotPose(:,thetaIdx);
thetaEuler = zeros(size(robotPose, 1), 3 * size(theta, 2));
thetaEuler(:, end) = theta;

for k = 1:size(xyz, 1)
show(map)
hold on;

% Plot Start Location
plotTransforms([startLoc, 0], eul2quat([0, 0, 0]))
text(startLoc(1), startLoc(2), 2, 'Start');

% Plot Goal Location
plotTransforms([goalLoc, 0], eul2quat([0, 0, 0]))
text(goalLoc(1), goalLoc(2), 2, 'Goal');

% Plot Robot's XY locations
plot(robotPose(:, 1), robotPose(:, 2), '-b')

% Plot Robot's pose as it traverses the path
quat = eul2quat(thetaEuler(k, :), 'xyz');
plotTransforms(xyz(k,:), quat, 'MeshFilePath',...
'groundvehicle.stl');

pause(0.01)
hold off;
end