OBSTACLE-AVOIDANCE NAVIGATION OF MULTIPLE MOBILE ROBOTS

In the context of robot soccer, the robots have to select actions to achieve individual and team goals in the dynamic environment. It is important for a robot to acquire navigation behaviors for avoiding other robots and obstacles in the real time environment. This paper suggested an efficient approach to collision avoidance in multi robot system. This approach is based on velocity information of moving objects and the distance between robot and obstacle in three specified directions. The main contribution of this paper is that it provides a method for robots with decreased computational cost and makes the robot navigate without collision with each other in a complicated environment.

Multi-Robot Collaborative Hunting in Cluttered Environments With Obstacle-Avoiding Voronoi Cells

This work proposes an online collaborative hunting strategy for multi-robot systems based on obstacle-avoiding Voronoi cells in a complex dynamic environment. This involves firstly designing the construction method using a support vector machine(SVM) based on the definition of buffered Voronoi cells(BVCs). Based on the safe collision-free region of the robots, the boundary weights between the robots and the obstacles are dynamically updated such that the robots are tangent to the buffered Voronoi safety areas without intersecting with the obstacles. Then, the robots are controlled to move within their own buffered Voronoi safety area to achieve collision-avoidance with other robots and obstacles. The next step involves proposing a hunting method that optimizes collaboration between the pursuers and evaders. Some hunting points are generated and distributed evenly around a circle. Next, the pursuers are assigned to match the optimal points based on the Hungarian algorithm.Then, a hunting controller is designed to improve the containment capability and minimize containment time based on collision risk. Finally, simulation results have demonstrated that the proposed cooperative hunting method is more competitive in terms of time and travel distance.

Design and Realization of Simple Intelligent Robotic Lawn Mower Based on Arduino Mega2560

Robotic lawn mowers available in markets are much more complicated with high cost, hence, a new robot is designed in the research. In detail, the control system is made up of Arduino Mega2560 and 11 sensors and the robot works with four wheels （two front and back wheels） driven by an electric motor. Furthermore, the platform of lawn-mowing is designed semicircle, equipped with three small high- speed and low-power electric motors; the cutting distance is determined by width of motherboard. In addition, the hardware of the system is made up of circuit control and working machines, of which the former includes a single chip unit, a wireless remote control, a sensor unit, an infrared array module, a driving module of electric motor, a display unit and a power source; the latter includes a mowing platform and a sensor window. In addition, the related software is programmed using C language and modular programming involving PWM program, Hall sensor program, liquid-crys- tal display, tilt program, supersonic sounding program, infrared obstacle-avoidance program, parking program, and remote control program. After hardware was adjust- ed, the robotic lawn mower was tested for multiple times in a standard lawn, and a satisfied effect was achieved.

A Technical Framework for Selection of Autonomous UAV Navigation Technologies and Sensors

The autonomous navigation of an Unmanned Aerial Vehicle(UAV)relies heavily on the navigation sensors.The UAV’s level of autonomy depends upon the various navigation systems,such as state measurement,mapping,and obstacle avoidance.Selecting the correct components is a critical part of the design process.However,this can be a particularly difficult task,especially for novices as there are several technologies and components available on the market,each with their own individual advantages and disadvantages.For example,satellite-based navigation components should be avoided when designing indoor UAVs.Incorporating them in the design brings no added value to the final product and will simply lead to increased cost and power consumption.Another issue is the number of vendors on the market,each trying to sell their hardware solutions which often incorporate similar technologies.The aim of this paper is to serve as a guide,proposing various methods to support the selection of fit-for-purpose technologies and components whilst avoiding system layout conflicts.The paper presents a study of the various navigation technologies and supports engineers in the selection of specific hardware solutions based on given requirements.The selection methods are based on easy-to-follow flow charts.A comparison of the various hardware components specifications is also included as part of this work.

SENSOR-BASED MOTION CONTROL USING ADAPTIVE NAVIGATION RULES IN THE DYNAMIC ENVIRONMENT FOR MOBILE ROBOT

In the multi-robots system, it's important for a robot to acquire adaptivenavigation rules for reaching the goal and avoiding other robots and obstacles and in the real-timeenvironment. An efficient approach to collision-avoidance in multi-robots system is suggested . Itis based on velocity information of moving objects and the distances between the robots and theobstacles in three specified directions and makes the robot navigate adaptively without collisionwith each other in a complicated situation. The effectiveness of algorithm is proved by the severalsimple examples in the physical world.

Obstacle-avoiding path planning for multiple autonomousunderwater vehicles with simultaneous arrival

This paper focuses on planning the obstacle-avoiding paths of multiple autonomous underwater vehicles(AUVs) in complex ocean environment, with the time coordination of simultaneous arrival. By imitating the nature phenomenon that river water avoids rocks and reaches the destination, the interfered fluid dynamical system(IFDS) is first presented to obtain the single-AUV path for obstacle avoidance, where the modulation matrix is calculated to quantify the influence of obstacles especially. Then the two-layer comprehensive adjustment to path length and voyage speed is utilized, aiming to achieve the simultaneous arrival at destination between multi-AUVs. By adjusting reactive parameters of IFDS, the former is to roughly ensure the intersection of AUVs' potential arrival time range to be non-null. On this basis, the latter adjusts each AUV's voyage speed finely using the consensus method with state predictor, which has faster convergence speed. If the multi-AUVs communication network is connected, the whole system will quickly converge to the consensus state, i.e., the estimated time of arrival(ETA) of each AUV tends to be equal. Finally, the simulation results verify the advantages of our proposed method.

Development of unilateral obstacle-avoiding mower for Y-trellis pear orchard

To solve the problem of weeding under Y-trellis pear orchards,a unilateral obstacle-avoiding mower(UOAM)was developed in this study.The mower is composed of an obstacle-avoiding disc mechanism,a hydraulic profiling mechanism,and a cutting disc mechanism.The diameter of the obstacle-avoiding disc was 0.7 m,which could swing around the trunk or ground pile actuated by the spring mechanism.The piston movement of the hydraulic cylinder controls the working position of the obstacle-avoiding disc.The maximum extension distance of the hydraulic profiling arm was 1 m.Based on the national standards and actual situation of orchards,the optimum parameters were determined with a combination of advancing speed of 0.44 m/s,rotation speed of the cutting disc at 2000 r/min,blade number of 2,and cutting edge length of 0.2 m.Finally,the design parameters were verified by the mathematical model of the blade cutting edge trajectory and multi-body dynamics simulation.Taking stubble cutting stability,leakage rate,working efficiency and costs as the test indexes,field performance comparison tests were carried out on the three operation modes of UOAM mowing,shoulder carrying mower(SCM)mowing and manual weeding.Test results showed that the coefficient variation of stubble cutting height of UOAM was the smallest,showing that the working stability of UOAM was better than the other two treatments.The leakage rate of UOAM was 2.42%,and its coefficient variation was lower than that of SCM.The working efficiency of UOAM was much higher than that of SCM and manual weeding,which was 4.44 times of SCM and 20 times of manual weeding.The profitable area of UOAM was 7.02 hm^(2),showing that it was suitable for large-scale mechanized Y-trellis pear orchards.