Algorithms for collision-free navigation of mobile robots in complex cluttered environments: a survey

Abstract

SUMMARYWe review a range of techniques related to navigation of unmanned vehicles through unknown environments with obstacles, especially those that rigorously ensure collision avoidance (given certain assumptions about the system). This topic continues to be an active area of research, and we highlight some directions in which available approaches may be improved. The paper discusses models of the sensors and vehicle kinematics, assumptions about the environment, and performance criteria. Methods applicable to stationary obstacles, moving obstacles and multiple vehicles scenarios are all reviewed. In preference to global approaches based on full knowledge of the environment, particular attention is given to reactive methods based on local sensory data, with a special focus on recently proposed navigation laws based on model predictive and sliding mode control.

A reactive collision avoidance algorithm for nonholonomic vehicles

“…Figure 6 shows that |ψ (2) dca | <ψ dca,sup during the simulation. Hence, sinceψ dca,sup < r max , the vehicle is able to perfectly follow ψ (2) dca after a transition period, which agrees with r max ≥ψ dca,sup . The obstacle distance remains greater than d safe , as seen in the top half of Figure 6.…”

“…The direction of the sides of the extended vision cone are denoted β (1) and β (2) . Two velocity vectors v β (1) and v β (2) are defined along the sides of the extended vision cone as…”

“…In order to achieve this, a compensated vision cone V o (t) is defined by compensating the extended vision cone for the obstacle velocity v o (t), as illustrated in Figure 3. The velocity vectors defining the sides of V o are x y β (2) v ca γ ca v β (2) γ vo (2) (2) then given by…”

“…However, since v (1) ca and v (2) ca are first order differentiable with angular velocity less thanψ dca,sup , and ψ dca is then chosen to be the closest of v (1) ca and v (2) ca by (21), the vehicle is immediately able to follow ψ dca to avoid the obstacle again.…”

“…The vehicle then proceeds towards the target in accordance with the pure pursuit guidance law (11). Distance between the vehicle and the obstacle in the first scenario(top), and the angular velocity of ψ (2) dca (bottom), which was used during the CA maneuver.…”