Mechatronics projects are projects related to Robotics and Control. I was able to cooperate in a few such projects in the University of Tehran while I was working on our paper. This list may also include some other extracurricular Mechatronics projects I may have done in my spare time during the last few years.
Control of a Ball on a Rotating Beam
This project was an exercise in Linear Modern Control. It was purely done in state space and all the codes were written in MATLAB or C++. The system's dynamic differential equations were derived, which were nonlinear needless to say, since they encompassed a plethora of trigonometric functions, its state space equations were built and linearized, and then a linear controller was designed for the linearized system. The linearized system was found to be fully controllable and observable around the equilibrium point.
Design and Analysis of a Pipe Inspection Robot
The objective of this project was to design a pipe inspection robot with a machining apparatus capable of repairing sewage pipes. We would design the layout and mechanism of the robot along with its dimensions, and then select particular parts for all of its different operations from existing catalogs. Almost all of the degrees of freedom of the robot I had designed were hydraulically actuated, and the tool itself was powered by an air motor. Pumps, electromotor-gearboxes, hydromotors, gear trains and hydraulic cylinders were used for actuation and operation. The only thing that this robot does not have is an adaptable traction mechanism to enable it to work in pipes while maintaining stability, even in bent or vertical pipes. Traction mechanisms are usually straight-forward and easy to design, encompassing a simple linkage system and a hydraulic cylinder.
This Pipe Inspection Robot employs wheels for locomotion, but some models use tracks for better friction. The wheels are driven by hydromotors connected to a differential system. The tool is connected to free-moving linkages that are actuated via hydraulic cylinders. Pipe Inspection Robots usually hold adjustable cameras as well, which are not shown here, because they are irrelevant to the project.
Design and Analysis of a Warehouse Robot
This project was similar to the Pipe Inspection Robot in nature, it was an exercise in Mechatronics, and part selection. A warehouse robot resembling a lift truck was designed, and its parts were selected from real-life catalogs. Furthermore, its programs for autonomy and control were written such that it could act autonomously, or remote-controlled. The robot uses Swedish wheels, and employs hydraulic motors for locomotion. It also uses many gears and gear trains for object handling. It has more degrees of freedom than a normal lift truck. It is also much smaller, simpler, and less complex.
Dynamic Analysis and Control of a 6-DOF Manipulator
This was a Robotics course project for M.Sc. students in University of Tehran, which I elected to partake in. I chose an ABB welding robot, since ABB posts its product specifications and CAD models on its website. I derived all of its Geometry, Denavit-Hartenberg Transformations, Forward and Inverse Kinematics, Jacobian, Dynamic Equations, and a PID controller for its joints in MATLAB and Simulink. I also derived its optimal-time control architecture, as well as a path planner and its tracking controller. The MATLAB-Simulink simulations and analyses were validated, and the robot was animated and catia and dynamically analyzed in SolidWorks Camworks.
Dynamic Modeling and Sliding-Mode Control of a Tractor-Trailer Wheeled Mobile Robot with Skidding Effects on the Wheels
In this team project, whose outcome eventually became a paper, a tractor-trailer wheeled mobile robot subjected to skidding effects is dynamically modeled. The well-known Newton-Euler method is utilized to derive the dynamic equations of the system, which are then expressed in compressed matrix form. In order to calculate the interaction between ground and wheel, the LuGre dynamic friction model is used. The behavior of an uncontrolled system has been simulated in MATLAB® using the derived dynamic equations, and then compared against a model designed in ADAMS®. The results match each other, proving the accuracy of the dynamic equations. Then, assuming that the response of the system subjected to skidding is similar to that of a system with pure-rolling under finite random disturbances on the input, a control law via sliding surfaces is established based on the dynamic equations of the pure-rolling model.
The response of a controller with disturbances implemented on a system with pure-rolling is then simulated in MATLAB® software and compared against that of a controller with no disturbance implemented on a system with skidding. With the results adequately close, the credibility of the assumption made therein is verified, along with the accuracy of the deigned controller.
Design and Construction of a Modular and Supplementary Mechanism for Increasing the Mobility of Wheeled Pipe Inspection Robots
In this team project whose outcome also became a paper, a novel mechanism is designed to increase mobility of industrial pipe inspection robots. This mechanism is a modular unit addable to the robot. The proposed mechanism has two degrees of freedom, one prismatic and one revolute, only one of which is actuated at a time. A high-power motor is used to actuate the mechanism and a switching system is utilized to select between the degrees of freedom. The maneuver of climbing over a step for a robot equipped with this module, involves lifting the front end of the robot, passing the center of mass of robot over the step, and then lifting the rear end of the robot in order to fully move the robot over the step. To this end, the module uses two different modes. In mode 1, when the arm of the module makes contact with the ground, the revolute joint is active and in mode 2, prismatic joint is active. A visual strategy for climbing over steps is proposed and after simulation, via experimentation, it is validated.
It is derived from the results that using mode 2 requires significantly less torque for the actuator, therefore mode 2 is selected for lifting one end of the robot in simulations and experiments. Empirical results of the tests demonstrate that the proposed mechanism can discernibly improve the mobility of pipe inspection robots when encountering steps and obstacles. Furthermore, the fundamental compactness of the devised module enables it to be used when geometrical limitations are imposed, such as pipes with relatively smaller diameters.