Julio C. Correa

Static Analysis of Tensegrity Structures: Part 1 — Equilibrium Equations

In this paper the mathematical model to perform the static analysis of an antiprism tensegrity structure subjected to a wide variety of external loads is addressed. The virtual work approach is used to deduce the equilibrium equations and a method based on the Newton’s Third Law to verify the numerical results is presented. In the second part of the paper several numerical examples are given.Copyright

Analysis of a Planar Tensegrity Mechanism for Ocean Wave Energy Harvesting

Tensegrity systems have been used in several disciplines such as architecture, biology, aerospace, mechanics, and robotics during the last 50 years. However, just a few references in literature have stated the possibility of using such systems in ocean or energy-related applications. This work addresses the kinematic and dynamic analyses of a planar tensegrity mechanism for ocean wave energy harvesting. Ocean wave mechanics and the most important concepts related to fluid–structure interaction are presented. Then, a planar 3 degrees of freedom (3-dof) tensegrity mechanism, based on a morphology defined by Kenneth Snelson in 1960 which is known as “X-frame,” is proposed as connecting linkage to transmit wave-generated forces. A geometric approach is used to solve the forward and reverse displacement problems. The theory of screws is used to perform the forward and reverse velocity analyses of the device. The Lagrangian approach is used to deduce the equations of motion considering the interaction between the mechanism and ocean waves. The tensegrity-based mechanism is analyzed using a linear model of ocean waves and its energy harvesting capabilities are compared to a purely heaving device. Results show that the proposed tensegrity configuration allows to harvest 10% more energy than the traditional heaving mechanism used in several wave energy harvesting applications. Therefore, tensegrity systems could play an important role in the expansion of clean energy technologies that help the worlds sustainable development.

Static Analysis of Tensegrity Structures: Part 2 — Numerical Examples

In this paper two examples are provided to demonstrate the use of the mathematical model developed in Part 1, as well as the verification method based on a Newtonian approach. The results are presented both graphically and numerically.Copyright

Static Analysis of Prestressed Tensegrity Structures

In this paper the mathematical model to perform the static analysis of a prestressed antiprism tensegrity structure subjected to an arbitrary reduction of its connecting ties is addressed. A virtual work approach is used to deduce the equilibrium equations and the numerical results are verified using a Newtonian approach. One example is provided to illustrate the mathematical model.Copyright

Kinematic Analysis of a Planar Tensegrity Mechanism for Wave Energy Harvesting

Tensegrity systems have been used in several disciplines such as architecture, biology, aerospace, mechanics and robotics during the last fifty years. However, just a few references in literature have stated the possibility of using them in ocean or energy-related applications. This work addresses the kinematic analysis of a planar 3–dof tensegrity mechanism for ocean wave energy harvesting. A planar tensegrity mechanism is proposed based on the “X-frame” morphology developed by Kenneth Snelson in 1960s. A geometric approach is used to solve the forward and reverse displacement problems. The theory of screws is used to perform the forward and reverse velocity analyses of the device. The result of shows that tensegrity systems could play an important roll in the expansion of clean energy technologies that help the world’s sustainable development.

Marine Energy Devices for Colombian Seas

There are several alternatives to obtain marine energy: waves, tides, currents, gradients of temperature and gradients of salinity. All of them have been studied extensively, however their implementation is closely related to the particular conditions of the local sea. This paper presents preliminary results related with the kind of the instrumentation required to monitor the behavior of the variables associated with marine energy and the best available technologies to take advantage of the marine power in the Colombian seas.Copyright

Implementation of a Laboratory for the Study of Robot Manipulators

This paper presents the process followed in the Department of Mechanical Engineering at Universidad Pontificia Bolivariana in Medellin, Colombia to implement a laboratory for the study of robot manipulators. The lab includes the following components: an industrial serial manipulator and the software developed for its integration to a graduate course, a parallel manipulator, a Cartesian robot, an inverted pendulum and a small serial manipulator. Except for the industrial robot, all the other devices were manufactured at the University. For all prototypes, specific software to control them has been developed.© 2010 ASME

Development and implementation of a low-level control system for the underwater remotely operated vehicle Visor3

This paper addresses the development and implementation of a low level control system for the underwater vehicle Visor3, developed by the Universidad Pontificia Bolivariana, located at Medellín, Colombia. Visor3 is an observation class ROV that was developed for surveillance and inspection of port facilities and underwater structures and has been used as a test platform for the development of robotic technology for underwater exploration of Colombian seas. Both, the control and navigation algorithms were implemented in the on-board processor (BeagleBone embedded computer). This processor is running an Ångström operating system which is a Linux distribution used in embedded devices with built-in components. The control and navigation algorithms were tested in a hardware in the loop (HIL) environment using a 6-DOF mathematical model of Visor3 before the real test. Results from the HIL simulation and experimental test are compared. Results show that the HIL is powerful tool for the NGC development of the ROV.

Online Simulation of Mechatronic Neural Interface Systems: Two Case-Studies

Neural interface systems (NIS) are widely used in rehabilitation and prosthetics. These systems usually involve robots, such as robotic exoskeletons or mechatronic arms, as terminal devices. We propose a methodology to assess the feasibility of implementing these kind of neural interfaces by means of an online kinematic simulation of the robot. It allows the researcher or developer to make tests and improve the design of the mechatronic devices when they have not been built yet or are not available. Moreover, it may be used in biofeedback applications for rehabilitation. The simulation makes use of the CAD model of the robot, its Denavit-Hartenberg parameters, and biosignals recorded from a human being. The proposed methodology was tested using surface electromyography (sEMG) signals from the upper limb of a 25-year-old subject to control a kinematic simulation of a KUKA KR6 robot.

Software for the Kinematic Analysis of a Serial Manipulator for Academic Purposes

This paper addresses the development of software created at the Universidad Pontificia Bolivariana, located in Medellin, Colombia, for the direct and reverse analyses of a serial robot manipulator. Results provided for the software are used for the simulation of the manipulator and also provides data for the control of a serial manipulator prototype. Both, the prototype and its control system were also developed at the University as part of a project to establish a robotics lab. Since joint angles control is affected by the complex relationships presented in the gear transmission mechanisms, the kinematics of gear transmissions is also studied. In this way appropriate mappings between actuators, links and the Cartesian space are established. Software requirements, architecture, and its implementation are addressed. The software includes user-friendly graphical environments that allow one to navigate through all the capabilities of the program. The software has been tested intensively in the prototype and can be extended to serial manipulators with the same structure but different dimensions. Authors expect that virtual tools as the presented in this paper, can help to reduce the time to understand concepts related to motion analysis in the fields of robotics.© 2014 ASME