Rapid Design and Analysis of Versatile Robotic Platform

Abstract

To accommodate the ever-expanding data warehouse market, it is necessary to implement a degree of industrial automation to meet maintenance requirements. With the expansion of cloud-based storage and many new and existing companies moving to automate their processes, the need for a more effective method to manage and maintain server warehouses with reduced manpower is necessary. In order to address the need, this design team has developed and prototyped — a platform that would meet the basic requirements for server retrieval. The model navigates on four wheels driven by stepper motors that allow for differential steering and navigation in an indexed workspace. In order to reach servers on both the top and bottom bays, a chassis with low ground clearance was fitted with a scissor lift mechanism. The two sides of the scissor lift are actuated by two stepper motors with a high-ratio gear reduction. The operating system for controls and sensors run on Robot Operating System (ROS) and are powered by a Raspberry Pi that can be remotely programmed and operated from a single network connected computer. For precise controllability of electromechanical devices, appropriately sized drivers and sensors were selected. A Simulink-based step response analysis of inrush current and torque was completed to aid in component selection. This computer-based simulation resulted in important data regarding transient and steady state dynamics of the electromechanical system. This information can be ultimately used to design a PI, PD, or PID controller to eliminate steady state and transient state error from the actual robot, ensuring precise control. Analysis was centered primarily on the lifting, driving, and control mechanisms. The structure of each system was analyzed to ensure proper dimensioning and material selection. At the same time, the mechatronic analysis was completed to ensure lifting requirements were met. Analysis was conducted on the motor shafts, scissor members, gears, and hardware resulting in a robust design. All of the physical parts were initially modeled to meet a minimum safety-factor and were later modified based on the results of finite element analysis studies. This approach will allow the robot to operate safely and effectively regardless of obstruction or human interference. The design and programming enable a single technician to manage a fleet of robots for large scale operations. Because of the simplicity of the robot, the mechanisms and electronics selected can be modified to accommodate specific customer needs. This electromechanical platform and electrical simulation serve as a basis for future research and development of autonomous data warehouse maintenance.