Hongbin Deng

Bio: Hongbin Deng is an academic researcher from Beijing Institute of Technology. The author has contributed to research in topics: Obstacle avoidance & Robot. The author has an hindex of 6, co-authored 28 publications receiving 118 citations.

The deformable quad-rotor: Design, kinematics and dynamics characterization, and flight performance validation

Abstract: To improve the obstacle surmounting performance of the quad-rotor vehicle, this paper focuses on designing, kinematically and dynamically characterizing a novel deformable quad-rotor that is based on the scissor-like foldable structures. The foldable structure allows that the volume of the quad-rotor can be tuned to dynamically adapt variously sized obstacles and small spaces. To generate the controllable deformation, the actuated angulated elements that are the essential components of the scissor-like foldable structure play an important role. The element design, its actuation mechanism and the corresponding configuration patterns for the new quad-rotor are presented in the paper in detail. The simulations on deformation properties and obstacle surmounting ability are then performed to verify the deformation capability of the structure. In addition, experiments were extensively conducted to test the controlled deformation of the structure as well to investigate the deformation induced effects to the activated quad-rotor airframe and its aerodynamics. All implementation results validate the effectiveness of the proposed deformable quad-rotor design, that is, it enables the new quad-rotor having excellent obstacle surmounting performance, adaptability, flight maneuverability, as well as minimal aerodynamics influences during deforming.

Multi-Robot Obstacle Avoidance Based on the Improved Artificial Potential Field and PID Adaptive Tracking Control Algorithm

Abstract: As for the obstacle avoidance and formation control for the multi-robot systems, this paper presents an obstacle-avoidance method based on the improved artificial potential field (IAPF) and PID adaptive tracking control algorithm. In order to analyze the dynamics and kinematics of the robot, the mathematical model of the robot is built. Then we construct the motion situational awareness map (MSAM), which can map the environment information around the robot on the MSAM. Based on the MSAM, the IAPF functions are established. We employ the rotating potential field to solve the local minima and oscillations. As for collisions between robots, we build the repulsive potential function and priority model among the robots. Afterwards, the PID adaptive tracking algorithm is utilized to multi-robot formation control. To demonstrate the validity of the proposed method, a series of simulation results confirm that the approaches proposed in this paper can successfully address the obstacle- and collision-avoidance problem while reaching formation.

A Virtual Spring Method for the Multi-robot Path Planning and Formation Control

Abstract: Path planning is a challenging and critical issue in robotics, which involves computing a collision-free path between initial and target. The formation control ensures the robots’ collaborative working. To address these two problems, an efficient virtual spring method for multi-robot path planning and formation control is proposed, and the interaction dynamic model is established to describe both logical and physical topology of the network. Based on the network model, the virtual spring method control law is designed, and aiming at the non-reachable and local minima problems, the virtual target search method is proposed. The robots can calculate an optimal path to the target in the predefined formation based on the control law and the virtual target search method. Finally, a series of simulation results confirm that the approaches proposed in this paper are feasible and efficient in the path planning and formation control for the multi-robot systems.

Motion Planning Algorithm of a Multi-Joint Snake-Like Robot Based on Improved Serpenoid Curve

Abstract: In order to study the winding motion of a multi-joint snake-like robot with multi-degree of redundancy in plane, a motion planning algorithm of a multi-joint snake-like robot based on improved Serpenoid curve equation is proposed in this paper. Firstly, the kinematics and dynamics models of a multi-joint snake-like robot are established, and the joint angle curve equation and the thrust expression of each joint of the robot relative to time are obtained. Next, the existing Serpenoid curve equation is improved to calculate the axial bending moment function with joint angle amplitude adjustment factor and turn angle adjustment factor. By analyzing the relationship between the forward thrust of the robot and the improved Serpenoid curve equation, a simple, efficient and reliable closed-loop control system was designed. Then, MATLAB and SimWise4D were used for simulation to obtain the motion trajectory of the robot based on the improved Serpenoid curve motion planning algorithm, and the influence of different parameters on the forward velocity of the multi-joint snake robot was analyzed. Finally, the validity of the motion planning algorithm of a multi-joint snake-like robot based on improved Serpenoid curve equation is verified by the actual experiment.

The Foldable Drone: A Morphing Quadrotor That Can Squeeze and Fly

Abstract: The recent advances in state estimation, perception, and navigation algorithms have significantly contributed to the ubiquitous use of quadrotors for inspection, mapping, and aerial imaging. To further increase the versatility of quadrotors, recent works investigated the use of an adaptive morphology, which consists of modifying the shape of the vehicle during flight to suit a specific task or environment. However, these works either increase the complexity of the platform or decrease its controllability. In this letter, we propose a novel, simpler, yet effective morphing design for quadrotors consisting of a frame with four independently rotating arms that fold around the main frame. To guarantee stable flight at all times, we exploit an optimal control strategy that adapts on the fly to the drone morphology. We demonstrate the versatility of the proposed adaptive morphology in different tasks, such as negotiation of narrow gaps, close inspection of vertical surfaces, and object grasping and transportation. The experiments are performed on an actual, fully autonomous quadrotor relying solely on onboard visual-inertial sensors and compute. No external motion tracking systems and computers are used. This is the first work showing stable flight without requiring any symmetry of the morphology.

Efficient and Complete Centralized Multi-Robot Path Planning.

Abstract: Multi-robot path planning is abstracted as the problem of computing a set of non-colliding paths on a graph for multiple robots. A naive search of the composite search space, although complete, has exponential complexity and becomes computationally prohibitive for problems with just a few robots. This work proposes an efficient and complete algorithm for solving a general class of multi-robot path planning problems, specifically those where there are at most n-2 robots in a connected graph of n vertices. The algorithm employs two primitives: a "push" operation where a robot moves toward its goal until no further progress can be made, and a "swap" operation that allows two robots to swap positions without altering the configuration of any other robot. Simulated experiments compare the proposed approach with several other centralized and decoupled planners, and show that the proposed technique has highly competitive computation time and easily scales to problems involving 100s of robots, solving them in under 5 seconds.

Agile Robotic Fliers: A Morphing-Based Approach.

Abstract: The aerial robot presented here for the first time was based on a quadrotor structure, which is capable of unique morphing performances based on an actuated elastic mechanism. Like birds, which are able to negotiate narrow apertures despite their relatively large wingspan, our Quad-Morphing robot was able to pass through a narrow gap at a high forward speed of 2.5 m.s− 1 by swiftly folding up the structure supporting its propellers. A control strategy was developed to deal with the loss of controllability on the roll axis resulting from the folding process, while keeping the robot stable until it has crossed the gap. In addition, a complete recovery procedure was also implemented to stabilize the robot after the unfolding process. A new metric was also used to quantify the gain in terms of the gap-crossing ability in comparison with that observed with classical quadrotors with rigid bodies. The performances of these morphing robots are presented, and experiments performed with a real flying robot passing through a small aperture by reducing its wingspan by 48% are described and discussed.

Design and Control of a Passively Morphing Quadcopter

Abstract: This paper presents a novel quadcopter design that uses passive rotary joints to enable rapid aerial morphing without the use of additional actuators. The normally rigid connections between the arms of the quadcopter and the central body are replaced by sprung hinges that allow for the arms of the quadcopter to fold downward when low thrusts are produced by the propellers, resulting in a reduction of the largest dimension of the vehicle by approximately 50%. The ability of the vehicle to reduce its size during flight allows, e.g., for the traversal of gaps through which a non-morphing quadcopter could not pass. The vehicle is designed such that existing quadcopter controllers and trajectory generation algorithms can be used, provided that some additional constraints on the control inputs are met. The nonlinear dynamics of the system are presented, and design rules are given that minimize transition time between configurations and maximize the available range of control inputs. A method for performing gap traversal maneuvers is proposed and validated experimentally.

Survey on Aerial Manipulator: System, Modeling, and Control

Abstract: The aerial manipulator is a special and new type of flying robot composed of a rotorcraft unmanned aerial vehicle (UAV) and a/several manipulator/s. It has gained a lot of attention since its initial appearance in 2010. This is mainly because it enables traditional UAVs to conduct versatile manipulating tasks from air, considerably enriching their applications. In this survey, a complete and systematic review of related research on this topic is conducted. First, various types of structure designs of aerial manipulators are listed out. Subsequently, the modeling and control methods are introduced in detail from the perspective of two types of typical application cases: free-flight and motion-restricted operations. Finally, challenges for future research are presented.