Fundamental Mechanics and Precision Control of Optical Axis Stability and Parallelism in Multi-Sensor Electro-Optical Pods

Abstract

Modern electro-optical pods incorporatemulti-spectral sensors for reconnaissance, target acquisition, and laser designation, where sub-milliradian optical axis stability and inter-sensor parallelism are critical for mission success. This paper establishes a unified theoretical framework combining rigid-body kinematics and deformable body mechanics to develop a physics-based stability metric through screw theory formulation, expressing the optical axis dynamics as ˙O = [ω]×O+v, with thermo-mechanical constraints [ω]×O < ω, v < v for engineering implementation. A novel computational geometry method evaluates multi-sensor alignment errors by solving Ei = si − (si · ˆO) ˆO + JTT + Jgg, where JT and Jg represent thermal and gravitational Jacobians. The rigid-flexible coupling model with multi-point constraints (MPC) reveals thermal dominance (0.49 mrad IR sensor pitch displacement at 60◦C, 272× gravitational effect), material sensitivity (CTE mismatch contributing 68% of TV sensor’s azimuthal error), and cross-axis coupling (19% LD error amplification under thermal gradients). However, due to the limitations of current experimental conditions, the experimental validation ismainly carried out in controlled environments. The current experimental validation shows <5% deviation between predicted andmeasured parallelismerrors across −20◦C to 60◦C. In the future, we will supplement the evaluation of the robustness of the control method through existing simulation verifications (such as adding vibration and temperature disturbance models) in the “experimental discussion” or “prospect” section, and clarify the research plan for actual environment testing. The framework provides design guidelines for optimal sensor placement minimizing JT F, temperaturedependent calibration protocols, and 0.1 mrad allocable margin for manufacturing tolerances. This methodology advances electro-optical system engineering fromempirical tuning tomodel-driven optimization, demonstrating 0.12 mrad (3σ) stability in field tests under ISO 9022 environmental stress profiles, with key innovations including the first integration of Lie algebra kinematics with FEM-based deformation analysis for optical systems and physics-informed error budgeting separating thermal, mechanical, and alignment components.

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