טכניון מכון טכנולוגי לישראל
הטכניון מכון טכנולוגי לישראל - בית הספר ללימודי מוסמכים  
M.Sc Thesis
M.Sc StudentBursak Alexander
SubjectDevelopment of the Flexible-Track Robot Robotrek
Capable of Autonomous Lucomotion
DepartmentDepartment of Mechanical Engineering
Supervisor Professor Elon Rimon
Full Thesis text - in Hebrew Full thesis text - Hebrew Version


Abstract

Locomotion of mechanisms on rough terrains is widely applied in various areas: transportation, agriculture, rescue, defense, and so on. Locomotion on tracks is a widespread solution, which greatly increases the robot’s traversability on non-rigid or non-smooth terrains. While tracks provide many benefits compared to wheels, there are many situations when obstacles are too difficult to overcome. This happens for example when an obstacle is slightly higher than the vehicle tracks.

This thesis presents the main design stages of the first prototype of a non-conventional single closed chain robot named RoboTrek with subsequent experimental analysis. This specific robot design allows passage over obstacles with height comparable to the chain’s length. Unlike conventional tracks stretched on a rigid frame with the help of tension wheels, this robotic chain is not stretched and uses its natural degrees of freedom at the connection of each link to preserve and change its shape. The single loop chain is driven by single axle motorized chassis, which gives high power and reliability to the robot. The joints connecting each pair of links may exist in three modes: free to rotate, completely locked in a specific angle position and locked in its natural limit position. Each locking unit is controlled mechanically during the robot’s motion.

Since this configuration of the robot mechanism has never been considered before, the work consists of the following design parts: mechanism analysis, dimensional analysis, strength calculation, assembly process analysis, experimental tests for the robot’s mechanism behavior observation and data collection. The assembly process is rather complex and requires design of special tools and accessories. Because of multiple degrees of freedom, this basic closed chain requires sensing and triggering of the chain’s links space orientation.  In order to protect different robot mechanism units from mechanical damage, design of the electro-mechanical protection system is required.

The results obtained in this work represent guidelines for subsequent mechanical and motion research and development of a single motor closed chain robot, to be discussed as later generation models.