Determination of a collision free path for a robot between start and goal positions through obstacles cluttered in a workspace is central to the design of an autonomous robot path planning. This paper presents an overview of autonomous mobile robot path planning focusing on algorithms that produce an optimal path for a robot to navigate in an environment. To complete the navigation task, the algorithms will read the map of the environment or workspace and subsequently attempts to create free paths for the robot to traverse in the workspace without colliding with objects and obstacles. Appropriate or correct and suitable algorithms will fulfill its function fast enough, that is, to find an optimal path for the robot to traverse in, even if there are a large number of obstacles cluttered in a complex environment. To achieve this, various approaches in the design of algorithms used to develop an ideal path planning system for autonomous mobile robots have been proposed by many researchers. Simulation and experimental results from previous research shows that algorithms play an important role to produce an optimal path (short, smooth and robust) for autonomous robot navigation and simultaneously it prove that appropriate algorithms can run fast enough to be used practically without time-consuming problem. This paper presents an overview and discusses the strength and weakness of path planning algorithms developed and used by previous and current researchers.

Research in the area of cooperative multi-agent robot systems has received wide attention among researchers in recent years. The main concern is to find the effective coordination among autonomous agents to perform the task in order to achieve a high quality of overall performance. Therefore, this paper reviewed various selected literatures primarily from recent conference proceedings and journals related to cooperation and coordination of multi-agent robot systems (MARS). The problems, issues, and directions of MARS research have been investigated in the literature reviews. Three main elements of MARS which are the type of agents, control architectures, and communications were discussed thoroughly in the beginning of this paper. A series of problems together with the issues were analyzed and reviewed, which included centralized and decentralized control, consensus, containment, formation, task allocation, intelligences, optimization and communications of multi-agent robots. Since the research in the field of multi-agent robot research is expanding, some issues and future challenges in MARS are recalled, discussed and clarified with future directions. Finally, the paper is concluded with some recommendations with respect to multi-agent systems.

Finding consensus is one of the most important tasks in multi-agent robot motion coordination research, especially in a communication environment. This justification underlies the use of event-triggered controller in current multi-agent consensus research. However, the communication issue has not been adequately addressed in a broadcast communication environment for rendezvous applications. Therefore, the broadcast event-triggered (BET) controller with a new formulation was designed using the Simultaneous Perturbation Stochastic Algorithm (SPSA). Theorems and relevant proofs were presented. Agent performances with the BET controller were evaluated and compared with the conventional broadcast time-triggered (BTT) controller. The results showed an effective motion generated by a multi-agent robot to reach the rendezvous point based on the Bernoulli distribution and gradient approximation of the agent local controller. The BET controller has proven to work more efficiently than the BTT controller when it reaches convergence in less than 40.42% of time and 21.00% of iterations on average. The utilization of communication channels is slightly reduced for BET, which is 71.09% usage instead of fully utilized by BTT. The threshold value of the event-triggered function (ETF) and SPSA parameters affected agent performances. Future research may consider using an effective and efficient BET controller in a complex communication environment with many variations of graph topology networks.