With the manufacturing industry taking shift from mass production to mid-volume and mid-variety, flexible manufacturing systems are increasingly in use. They require not only machine flexibility but also flexible material handling, storage & retrieval systems. Being the most versatile material movement system, Mobile Robots got the most deserved attention over time. To understand in depth about the deep technical aspects of a mobile robotic system, lets delve more into what constitutes this & what are the important components of this whole robotic system.
A mobile robot is more than just a single vehicle; it’s a system with integration of several components that form the building blocks. As observed earlier, the navigation system & the control systems are at the heart of the system that act as the guiding force for these vehicles. Other principle components include the safety system, traffic management system, battery charging system, and the hardware components like the body of mobile robot, payload..etc.
Broadly we can divide the components of mobile robot into 2 parts; software & hardware.
The critical software components that run the mobile robot are:
Navigation System: Navigation system guides the path of autonomous vehicles and it can be a closed path or an open path. Closed path systems are used in case of automated guided vehicles, where a predetermined path plan will be there, and the path is laid by physical objects like wired navigation technology or guided tape system.
Mobile robots rather operate on open path system, that is laser sensor navigation system, or lidar based natural navigation where the best path will be decided in real-time according to the changes in the environment. These are advanced systems over closed path systems, and offer much flexibility. The type of navigation system can be chosen depending on the requirement of the operations & the environment in which it operates.
Control System:Control system integrates mobile robot with the Fleet (other mobile robots), WMS/WCS and also the user interface. This is a centralized system that drives the entire functionality of mobile robot by interacting with WMS/WCS/ERP for job initiation, managing the movement by calculating the optimal path, uploading and discharging of payload as per the given commands. In case of advanced navigation systems, like natural navigation or laser-based navigation it stores the map of the entire warehouse and directs the mobile bot based on the input commands.
Safety System: Safety system consists of a set of sensors and bumpers in the interior architecture of the mobile robot. These sensors take care of localization of the mobile robot, and collision avoidance. They offer 2 level safety system, one for slowdown of bot upon detection of an avoidance & the other for stopping of the mobile robot to prevent collision. These sensors help in positioning of the mobile bot w.r.t the surrounding system.
Fleet Management System:Fleet management system organizes and manages the movement of AGVs in the given area such that no collisions will happen among the vehicles and with people or other objects. More importantly it facilitates the proper integration of AGVs among themselves & external equipment such as forklifts, conveyors, shuttles ..etc.
The critical hardware components that run the mobile robot are:
Energy Supply: Energy supply to mobile robot takes care of: Vehicle guidance control, electrical, electronic and sensory systems, mechanical moving components and load transfer equipment.
Basic methods used for energy supply to mobile robots include:
• Traction batteries (electric vehicle batteries, or EVBs) (lead or NiCd batteries)
• Non-contacting energy transfer
• Hybrid Systems: Non-contacting energy transfer plus a small auxiliary battery
All these technologies have their justifications in terms of cost, battery life time, time needed for a full cycle charging, type of operations, power density..etc, hence depending on the requirement one can choose the system.
Payload: Payload is the maximum weight carried by the mobile robot, and it depends on the mechanical structure, motor specifications. Depending on the requirement, it can be scalable to any external MHE like a fork, conveyor, liftdeck and tow trucks.
Safety System: On the hardware part, the safety system of mobile robot will have different alert mechanisms like buzzer sounds, optical warning lights and acoustic warning signals, which include blinkers to indicate a change of direction as with automobiles, but with acoustic support.
These individual components make up one whole system that provides flexible material movement from one point to another without the need of any fixed conveyor networks or any laid paths on the floor or ceiling. To know more about how superior these systems are over its older counterparts, watch this space.
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