核心概念
This paper presents a novel non-conservative collision avoidance technique using convex optimization to establish the distance between robotic spacecraft and space structures for autonomous on-orbit assembly operations.
要約
The paper proposes a novel approach to reformulate the collision avoidance problem by precisely modeling complex-shaped, full-dimensional controlled vehicles and obstacles using a series of differentiable convex functions. These functions are used as constraints in a convex optimization problem to establish the minimum distance between any two convex sets. The optimality condition of this optimization problem forms a new set of differentiable constraints that can be used in an optimal control problem to generate collision-free trajectories.
The effectiveness of the proposed method is demonstrated in two autonomous on-orbit assembly scenarios in tight environments, where the robotic spacecraft performs the assembly procedure. A pseudo-spectral optimal control method is utilized to show that the proposed technique can generate optimal trajectories in tight environments with multiple active components present.
The key highlights and insights are:
- The controlled vehicle and obstacles are modeled using real-valued, differentiable, convex functions, which are then used in a convex optimization problem to establish the minimum distance between them.
- The optimality conditions of this convex optimization problem are used to formulate a new set of differentiable constraints that can be incorporated into an optimal control problem to enforce collision avoidance.
- The proposed method is non-conservative and can handle full-dimensional controlled vehicles and obstacles, making it suitable for autonomous on-orbit assembly operations in tight environments.
- Numerical simulations of two assembly scenarios demonstrate the effectiveness of the proposed technique in generating optimal, collision-free trajectories for the robotic spacecraft.
統計
The maximum available thrust and torque were selected as 0.02 N and 0.01 N.m, respectively.
The robotic spacecraft unit's mass and inertia were considered 3 kg and 5 kg/m^2, respectively.
20 nodes were used for discretization in Scenario A.
引用
"The collision avoidance constraints are prominent as non-convex, non-differentiable, and challenging when defined in optimization-based motion planning problems."
"The necessity of proposing a collision avoidance technique that is not conservative in any manner, is designed for full-dimensional spacecraft and obstacles, and is comprehensive to incorporate the space robotics applications, as well as other applications, is evident."