Motion control of the wedge prisms in Risley-prism-based beam steering system for precise target tracking

Area of Science:

• Optics and Photonics
• Mechanical Engineering
• Control Systems

Background:

• Risley prisms are optical devices used in beam steering systems.
• Previous research provided exact inverse solutions for Risley prisms.
• Understanding the relationship between beam slewing and prism angular velocities is crucial for target tracking.

Purpose of the Study:

• To investigate the nonlinear relationship between beam slewing rate and prism angular velocities in a Risley-prism-based system.
• To analyze the limited regions and singularity points within the field of regard.
• To identify methods for avoiding control singularities.

Main Methods:

• Calculating gradients of the scan field based on existing inverse solutions.
• Analyzing the nonlinear dynamics of the Risley-prism-based beam steering system.
• Investigating system performance concerning limited regions and singularity points.

Main Results:

• The maximum rotational velocities for both prisms are similar and depend on the altitude angle.
• The central limited region of the field of regard is largely independent of prism parameters.
• Control singularities at the center path can be avoided by switching between the two inverse solutions.

Conclusions:

• The nonlinear dynamics of Risley prisms in target tracking systems are characterized.
• The study provides insights into managing operational limitations and singularities.
• Switching inverse solutions offers a practical method to overcome control singularities.