Simple demo of bicycle model

bicycle_model.py

import matplotlib.pyplot as plt
from math import *
import numpy as np
import matplotlib.patches as patches

# reference https://dingyan89.medium.com/simple-understanding-of-kinematic-bicycle-model-81cac6420357
class Bicycle(object):
    def __init__(self):
        self._length =0.1 # m
        self._width = 0.01
        # position of rear axis
        self._x = 0.0 # m
        self._y = 0.0 # m
        self._orientation = 0.0 # rad
        self._steer_angle = 0.0 # rad
        self._steer_rate = 0.0 # rad/s
        self._velocity = 0.0 # m/s

    @property
    def x(self):
        return self._x

    @property
    def y(self):
        return self._y

    @property
    def length(self):
        return self._length

    @property
    def width(self):
        return self._width

    @property
    def orientation(self):
        return self._orientation

    def set_steer_angle(self, angle):
        self._steer_angle = angle

    def set_velocity(self, velocity):
        self._velocity = velocity

    def drive(self, dt):
        self._x += self._velocity * cos(self._orientation)
        self._y += self._velocity * sin(self._orientation)
        orientation_rate = self._velocity * tan(self._steer_angle) / self._length
        self._orientation += orientation_rate * dt


def plot(bicycle, ax, color):
    rect = patches.Rectangle((bicycle.x,bicycle.y), bicycle.length, bicycle.width, bicycle.orientation/pi*180, linewidth=2,edgecolor=(color,0,0),facecolor='none')
    ax.add_patch(rect)

fig,ax = plt.subplots(1)
axes = plt.gca()
axes.set_xlim([-5,5])
axes.set_ylim([-5,5])
b = Bicycle()
dt = 0.1
b.set_velocity(0.1)
b.set_steer_angle(pi/6)
steps = 100
for i in range(steps):
    plot(b,ax, float(i)/float(steps))
    b.drive(0.1)
plt.show()