A tethered marsupial robotics system comprises three components: an Unmanned Ground Vehicle (UGV), an Unmanned Aerial Vehicle (UAV), and a tether connecting both robots. Marsupial systems are highly beneficial in industry as they extend the UAV's battery life during flight. This paper introduces a novel strategy for a specific path planning problem in marsupial systems, where each of the three components must avoid collisions with ground and aerial obstacles modeled as 3D cuboids. Given an initial configuration in which the UAV is positioned atop the UGV, the goal is to reach an aerial target with the UAV. We assume that the UGV first moves to a position from which the UAV can take off and fly through a vertical plane to reach an aerial target. We propose an approach that discretizes the space to approximate an optimal solution, minimizing the sum of the lengths of the ground and air paths. First, we assume a taut tether and use a novel algorithm that leverages the convexity of the tether and the geometry of obstacles to efficiently determine the locus of feasible take-off points for the UAV. We then apply this result to scenarios that involve loose tethers. The simulation test results show that our approach can solve complex situations in seconds, outperforming a baseline planning algorithm based on RRT* (Rapidly exploring Random Trees).

Abstract Given a finite set of weighted points in $${\mathbb {R}}^d$$ R d (where there can be negative weights), the maximum box problem asks for an axis-aligned rectangle (i.e., box) such that the sum of the weights of the points that it contains is maximized. We consider that each point of the input has a probability of being present in the final random point set, and these events are mutually independent; then, the total weight of a maximum box is a random variable. We aim to compute both the probability that this variable is at least a given parameter, and its expectation. We show that even in $$d=1$$ d = 1 these computations are #P-hard, and give pseudo-polynomial time algorithms in the case where the weights are integers in a bounded interval. For $$d=2$$ d = 2 , we consider that each point is colored red or blue, where red points have weight $$+1$$ + 1 and blue points weight $$-\infty $$ - ∞ . The random variable is the maximum number of red points that can be covered with a box not containing any blue point. We prove that the above two computations are also #P-hard, and give a polynomial-time algorithm for computing the probability that there is a box containing exactly two red points, no blue point, and a given point of the plane.

Consider a set of receptors belonging to two competitive telecommunication firms, the blue firm and the red firm. The receptors are represented as points in the plane, b are blue and belong to the blue firm and r are red and belong to the red firm. The blue firm has an emitting device represented as a point that moves along a path sending information to blue receptors as follows: At any time, the device sends information to all blue receptors covered by the largest disk centered at it and contains no red receptor. In this scenario, we study two optimization problems. The first problem is to compute a path, P, such that the number of blue receptors served by a moving device is maximized. In particular, we give efficient algorithms when P is a straight line, an anchored half-line and an axis-parallel double ray. As a second task, we study the problem of removing the minimum number of red receptors in such a way that there exists a straight line path P so that if the device moves along P all blue receptors are served. We prove geometrical properties of an optimal straight line and propose efficient algorithms depending on the degrees of freedom of the line.