Samuel N. Cubero

Dynamics and Control of a VTOL Quad-Thrust Aerial Robot

Some possible useful applications for Vertical Take-Off & Landing (VTOL) Unmanned Aerial Vehicles (UAVs) include remote video surveillance by security personnel, scouting missions or munitions delivery for the military, filming sports events or movies from almost any angle and transporting or controlling equipment. This paper describes the design, control and performance of a low-cost VTOL quadrotor UAV, known as the QTAR (Quad Thrust Aerial Robot).

Blind Search Inverse Kinematics for Controlling All Types of Serial-link Robot Arms

The main objective of “Inverse Kinematics” (IK) is to find the joint variables of a serial-link manipulator to achieve a desired position and orientation relationship between the end-effector frame and a base (or reference) frame. This paper describes a general purpose Inverse Kinematics (IK) method for solving all the joint variables for any type of serial-link robotic manipulator using its Forward Kinematic (FK) solution. This method always succeeds in solving the IK solution for any design of articulated, serial-link robot arm. It will always work on any design of serial-link manipulator, regardless of the number or types of joints or degrees of freedom (rotary and/or translational) and it is simple and easy enough to be implemented into robot arm design and simulation software, even automatically, without any need for complex mathematics or custom derived equations. Known as the “Blind Search” method, it also works on robots with redundant joints and with workspace internal singularities and will not become unstable or fail to achieve an IK solution. Robot arm design and 3D simulation software has been written and has successfully demonstrated that the “Blind Search” algorithm can be used as a general-purpose IK method that is capable of controlling all types of robot arm designs and even 3D animated objects and characters. The speed of solving IK solutions numerically is dependent on software design, selected search parameters and processing power.

A Mobile Manipulator Arm for Assisting the Frail Elderly and Infirm

This paper justifies the need for more research in the area of ‘assistive robotics’ and it describes the design and performance of a manipulator arm and gripper, mounted on an electric scooter, that can enable frail elderly and people with disabilities to collect and retrieve heavy objects, such as shopping items, located on high shelves. Known by the acronym ‘ESRA’, short for ‘Electric Scooter Robot Arm’, this device can be attached to a mobile vehicle like an electric scooter or an electric-powered wheelchair. This paper discusses the basic mechanical design of the ESRA manipulator and gripper, joint control, important design tools and failure analysis that were used for its development, and overall performance of the prototype arm. The object retrieval performance of this manipulator can also be enhanced using machine vision techniques for automatic object detection and gripper guidance. Different end-effector tools can be mounted on the end of the ESRA to enable the operator to perform a wide variety of common household chores and manipulation tasks.

Developing the Creativity and Design Skills of Mechatronic Engineering Students with Labs and Robot Competitions

This paper discusses the benefits of using competitions in the teaching activities for a 1st or 2nd year mechatronic engineering subject that teaches microcontrollers and/or mobile robotics using a ‘hands on’ PBL (Problem Based Learning) approach to learning and assessment. It describes, in detail, effective competition design philosophies and guidelines for creating different types of robotics competitions (and their rules) which help to keep students highly motivated and engaged in their learning and self-education. A ‘hands on’ one-semester microcontroller programming subject is used to illustrate three different case studies (competitions) that were implemented. This particular subject achieved very high satisfaction marks in student surveys and attracted a great deal of praise from students. The same teaching principles and similar kinds of technical competitions can also be used to achieve successful learning outcomes in other kinds of technical or engineering related subjects. This paper also describes general principles for designing an effective lab based course structure and how technical concepts and materials can be presented, learned quickly, and assessed in order to produce very interested and highly motivated students who are keen to teach themselves practical real world skills with minimum stress and maximum enjoyment. The case studies include a robotic racing car competition, a multi-player box grabbing contest over a rocky obstacle course and a ‘robot wars / robot sumo’ style competition that was televised nationwide in Australia.

Game Development Tools for Simulating Robots and Creating Interactive Learning Experiences

There are several different ways to create and control virtual 3D (three-dimensional) models of robots, however, most of these methods can only be implemented or understood by experts with years of extensive experience in 3D graphics programming, 3D mathematics and a plethora of advanced skills in the areas of solid modelling and 3D animation. This paper presents a brief history and summary of the state-of-the-art in 3D game development tools and technologies which can be used to develop realistic looking graphics for developing user interfaces and robot control programming tools. It also presents a simple and easy-to-learn kinematic modelling and 3D simulation process using a 4 degree of freedom (4-dof) articulated robot leg for an amphibious walking and swimming robot that is currently being designed by the authors. This 4-dof robot leg will be used as an example or case study to demonstrate an effective method for motion control, animation and simulation. Also described are popular software tools and essential skills needed to create a simple 3D simulation program. The source code of the 3D simulation software for the 4-dof robot leg is listed and described to help readers apply such methods to other robot designs, devices and complex machinery.

Design concepts for an energy-efficient amphibious unmanned underwater vehicle

This paper describes the conceptual design and operating principles of an oscillating-foil propulsion system for an unmanned underwater vehicle called TURTLE (‘Tele-operated Unmanned Robot for Telemetry and Legged Exploration’), currently under development. This UUV (‘Unmanned Underwater Vehicle) will be designed to be a 6-legged swimming and walking amphibious robot, fitted with foils (or flat fins) which can be manipulated with several degrees of freedom to produce highly efficient underwater propulsion forces. The legs will each have four degrees of freedom, of which the fourth is rotation of a foil that is fitted to the ’shin’ to provide propulsion for swimming. By manipulating the movements and rotations of this foil, propulsion forces can be generated to implement a variety of swimming modes, each with its own advantages and disadvantages. The foils attached to the fins allow the main body to be controlled in all six degrees of freedom. It will also be an amphibious robot that will be able to transition between swimming mode and walking mode, for walking on an underwater surface or over dry land if power considerations permit. It must be powerful and strong enough to support itself and light payloads while walking over rough or undulating surfaces commonly found on a beach. The mechanical design will allow the absolute position and orientation of the body to be accurately controlled relative to the ground surface, whether above or below water, for the purpose of precision control of onboard tools and sensors. The space frame construction method keeps water drag low and allows large scale, strong, rigid structures and manipulator limbs (or links) to be built. Space frames also keep material cost, weight and actuator energy usage to very low levels. Such lightweight and energy efficient robots will be useful in many practical applications, such as oil and gas exploration, drilling, mining, construction, automated agriculture, military transport and space exploration.