Guaranteed Collision Avoidance for Autonomous Systems with Acceleration Constraints and Sensing Uncertainties

Rodriguez-Seda, Erick J.; Stipanović, Dušan M.; Spong, Mark W.

doi:10.1007/s10957-015-0824-7

Cited by 29 publications

(16 citation statements)

References 41 publications

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“…The vector η i ∈ R n is a bounded, discontinuous, small perturbation to the control input aimed to avoid potential deadlocks [36] and chosen as…”

Section: A Online Reactive Planner (Virtual System)mentioning

confidence: 99%

“…As discussed in [36,37], deadlocks (or unwanted local minima) are the result of symmetries among attractive and repulsive potential functions. For the case of two agents, [36] proves that the use of a control perturbation perpendicular to the vehicle's trajectories, such as η i , can be used to successfully break these symmetries. However, it does not guarantee convergence in the general multi-agent case.…”

Section: Remarkmentioning

confidence: 99%

“…Under the presence of deadlocks we cannot guarantee convergence of the virtual system to the desired trajectory. Note, however, that the control perturbation η i in (7) should aid the vehicles in escaping deadlocks as shown in [36]. Remark 4.…”

Section: Trajectory Trackingmentioning

confidence: 99%

See 2 more Smart Citations

Decentralized Cooperative Collision Avoidance Control for Unmanned Rotorcraft with Bounded Acceleration

Rodriguez-Seda

Dawkins

2018

Journal of Guidance, Control, and Dynamics

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“…The vector η i ∈ R n is a bounded, discontinuous, small perturbation to the control input aimed to avoid potential deadlocks [36] and chosen as…”

Section: A Online Reactive Planner (Virtual System)mentioning

confidence: 99%

Section: Remarkmentioning

confidence: 99%

See 1 more Smart Citation

Decentralized Cooperative Collision Avoidance Control for Unmanned Rotorcraft with Bounded Acceleration

Rodriguez-Seda

Dawkins

2018

Journal of Guidance, Control, and Dynamics

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“…The redundancy of manipulators can be used to achieve secondary goals, such as joint limits avoidance [1], obstacle avoidance [2][3][4], minimization of joint torque [5], etc., without disturbances to the main task [6]. In order to drive redundant manipulators, an appropriate sequence of joint velocities is generated from the desired velocity of the endeffector and the predefined constraints of the inverse kinematics (IK) [7].…”

Section: Introductionmentioning

confidence: 99%

“…O. Khatib [3] established an artificial potential field around obstacles and substituted potential forces into the dynamical equation of manipulators. The application of harmonic potential functions can be seen in [4], and some other definitions of potential functions have been provided in recent work [18,19]. However, methods based on artificial potential field achieve obstacle avoidance in a dynamical way and are not applicable when manipulators' dynamical parameters, such as link masses, positions of mass centres, inertias, etc., are unknown.…”

Section: Introductionmentioning

confidence: 99%

Obstacle Avoidance for Redundant Manipulators Utilizing a Backward Quadratic Search Algorithm

Qian

2016

International Journal of Advanced Robotic Systems

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Obstacle avoidance can be achieved as a secondary task by appropriate inverse kinematics (IK) resolution of redundant manipulators. Most prior literature requires the timeconsuming determination of the closest point to the obstacle for every calculation step. Aiming at the relief of computational burden, this paper develops what is termed a backward quadratic search algorithm (BQSA) as another option for solving IK problems in obstacle avoidance. The BQSA detects possible collisions based on the root property of a category of quadratic functions, which are derived from ellipse-enveloped obstacles and the positions of each link's end-points. The algorithm executes a backward search for possible obstacle collisions, from the end-effector to the base, and avoids obstacles by utilizing a hybrid IK scheme, incorporating the damped least-squares method, the weighted least-norm method and the gradient projection method. Some details of the hybrid IK scheme, such as values of the damped factor, weights and the clamping velocity, are discussed, along with a comparison of computational load between previous methods and BQSA. Simulations of a planar seven-link manipulator and a PUMA 560 robot verify the effectiveness of BQSA.

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Deadlock Analysis and Resolution for Multi-robot Systems

Grover¹,

Liu²,

Sycara³

2021

Springer Proceedings in Advanced Robotics

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Collision avoidance for multirobot systems is a well studied problem. Recently, control barrier functions (CBFs) have been proposed for synthesizing decentralized controllers that guarantee collision avoidance (safety) and goal stabilization (performance) for multiple robots. However, it has been noted in several works that reactive control synthesis methods (such as CBFs) are prone to deadlock, an equilibrium of system dynamics that causes the robots to come to a standstill before they reach their goals. In this paper, we analyze the incidence of deadlocks in a multirobot system that uses CBFs for goal stabilization and collision avoidance. Our analysis is formal, in that we demonstrate that system deadlock is indeed the result of a force-equilibrium on robots. We show how to interpret deadlock as a subset of the state space and prove that this set is non-empty, bounded, of measure zero and located on the boundary of the safe set. Based on this analysis, we develop a decentralized three-phase algorithm that uses feedback linearization to ensure that the robots provably exit the deadlock set and converge to their goals while avoiding collisions. We show simulation results and experimentally validate the deadlock resolution algorithm on Khepera-IV robots.

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Guaranteed Collision Avoidance for Autonomous Systems with Acceleration Constraints and Sensing Uncertainties

Cited by 29 publications

References 41 publications

Decentralized Cooperative Collision Avoidance Control for Unmanned Rotorcraft with Bounded Acceleration

Decentralized Cooperative Collision Avoidance Control for Unmanned Rotorcraft with Bounded Acceleration

Obstacle Avoidance for Redundant Manipulators Utilizing a Backward Quadratic Search Algorithm

Deadlock Analysis and Resolution for Multi-robot Systems

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