Coplanar Tripteron Inverse Kinematics

cotript.py

#!/usr/bin/env python

from __future__ import print_function

import math


angle = math.radians(35)  # Arm offset angle
t = math.tan(angle)       # Store tangent

# Tower rotations
beta_a = math.radians(120)
gamma_a = math.radians(240)

# Actuator coefficients
alpha_x = 0   # sin(0) = 0 * t = 0
alpha_y = t  # cos(0) = 1 * t = t
beta_x = math.sin(beta_a) * t
beta_y = math.cos(beta_a) * t
gamma_x = math.sin(gamma_a) * t
gamma_y = math.cos(gamma_a) * t

# Platform movement vector
x = 0
y = 0
z = 1

# Inverse Kinematics
alpha = x*alpha_x - y*alpha_y + z
beta = x*beta_x - y*beta_y + z
gamma = x*gamma_x - y*gamma_y + z

print("alpha: {}; beta: {}; gamma: {}".format(alpha, beta, gamma))