pybeltsolver 0.1.1

Geometric solver and visualizer for 2D generic belt systems.

Geometric Solver and Visualizer for 2D Generic Belt Systems

This module provides the Belt and Circle classes to define, validate, and solve the geometry of a closed-loop belt-like system with no restrictions on the number of pulleys. It also supports custom routing topologies (front/back) via the BeltFace class, and dynamic length optimization via SciPy. Visualization is provided through Matplotlib. Axes and Figures are returned.

Examples

Standard 2-Pulley System

c1 = Circle(40.0, (0, 0), name="Drive Motor")
c2 = Circle(40.0, (250, 0), name="Driven Wheel")

pulleys = [c1, c2]
routing = [BeltFace.FRONT, BeltFace.FRONT]

belt = Belt(circles=pulleys, topology=routing, allow_crossing=False)
print(f"Total Belt Length: {belt.total_length:.2f}")
belt.plot()

Three-Pulley System with Mixed Routing and Optimization

import numpy as np

c1 = Circle(52 * 2 / np.pi / 2, (0, 0), name="c1")
c2 = Circle(23 * 2 / np.pi / 2, (10, 50), name="c2")
c3 = Circle(20 * 2 / np.pi / 2, (0, 78.87), name="c3")

pulleys = [c1, c2, c3]
routing = [BeltFace.FRONT, BeltFace.BACK, BeltFace.FRONT]

belt = Belt(circles=pulleys, topology=routing, allow_crossing=True)
print(f"Original Length: {belt.total_length:.2f}")

# Slide the tensioner (c2) along the X-axis to reach exactly 240 units
belt.find_movable_circle_position(
    target_length=240, movable_circle_idx=1, slide_vector=np.array([1, 0])
)
print(f"New Length: {belt.total_length:.2f}")
belt.plot()

4-Pulley System (Default Topology)

c1 = Circle(40.0, (0, 0), name="c1")
c2 = Circle(40.0, (250, 0), name="c2")
c3 = Circle(20.0, (240, -75), name="c3")
c4 = Circle(40.0, (100, -160), name="c4")

pulleys = [c1, c2, c3, c4]

# Topology defaults to all BeltFace.FRONT if not specified
belt = Belt(circles=pulleys, allow_crossing=False)
print(f"Total Belt Length: {belt.total_length:.2f}")
belt.plot()

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Author: Vincent Wallsten
Date: 2026-06-23