Kinematics, workspace and singularity analysis of a multi-mode parallel robot

A family of reconfigurable parallel robots can change motion modes by passing through constraint singularities by locking and releasing some passive joints of the robot. This paper is about the kinematics, the workspace and singularity analysis of a 3-PRPiR parallel robot involving lockable Pi and R (revolute) joints. Here a Pi joint may act as a 1-DOF planar parallelogram if its lock-able P (prismatic) joint is locked or a 2-DOF RR serial chain if its lockable P joint is released. The operation modes of the robot include a 3T operation modes to three 2T1R operation modes with two different directions of the rotation axis of the moving platform. The inverse kinematics and forward kinematics of the robot in each operation modes are dealt with in detail. The workspace analysis of the robot allow us to know the regions of the workspace that the robot can reach in each operation mode. A prototype built at Heriot-Watt University is used to illustrate the results of this work.Comment: International Design Engineering Technical Conferences \& Computers and Information in Engineering Conference, Aug 2017, Cleveland, United States. 201

Kinematically Redundant Octahedral Motion Platform for Virtual Reality Simulations

We propose a novel design of a parallel manipulator of Stewart Gough type for virtual reality application of single individuals; i.e. an omni-directional treadmill is mounted on the motion platform in order to improve VR immersion by giving feedback to the human body. For this purpose we modify the well-known octahedral manipulator in a way that it has one degree of kinematical redundancy; namely an equiform reconfigurability of the base. The instantaneous kinematics and singularities of this mechanism are studied, where especially "unavoidable singularities" are characterized. These are poses of the motion platform, which can only be realized by singular configurations of the mechanism despite its kinematic redundancy.Comment: 13 pages, 6 figure

Reconfiguración asimétrica de un manipulador paralelo de 3-gdl

In this paper an asymmetric reconfigurable parallel manipulator is presented. Asymmetric configurations are obtained by modifying the angle between each of the kinematic chains. Thanks to the reconfiguration proposal significant improvement of the manipulator performance can be obtained with respect to a Delta-type parallel robot. The computation of the best condition number is obtained, the results show that by using the redundancy, all the performance indices that depend on the Jacobian matrix can be improved as well.En este trabajo se presenta un manipulador paralelo reconfigurable asimétrico. Al modificar los ángulos de cada una de las cadenas cinemáticas pueden obtenerse configuraciones asimétricas. Gracias a la reconfiguración propuesta pueden generarse mejoras significativas del desempeño del manipulador, con respecto a un robot paralelo tipo Delta. El cálculo del mejor número de condición es obtenido, los resultados muestran que usando la redundancia todos los índices de desempeño que dependen de la matriz Jacobiana pueden ser mejorados también

Correct-by-Construction Approach for Self-Evolvable Robots

The paper presents a new formal way of modeling and designing reconfigurable robots, in which case the robots are allowed to reconfigure not only structurally but also functionally. We call such kind of robots "self-evolvable", which have the potential to be more flexible to be used in a wider range of tasks, in a wider range of environments, and with a wider range of users. To accommodate such a concept, i.e., allowing a self-evovable robot to be configured and reconfigured, we present a series of formal constructs, e.g., structural reconfigurable grammar and functional reconfigurable grammar. Furthermore, we present a correct-by-construction strategy, which, given the description of a workspace, the formula specifying a task, and a set of available modules, is capable of constructing during the design phase a robot that is guaranteed to perform the task satisfactorily. We use a planar multi-link manipulator as an example throughout the paper to demonstrate the proposed modeling and designing procedures.Comment: The paper has 17 pages and 4 figure

Kinematic analysis of a single-loop reconfigurable 7R mechanism with multiple operation modes

This paper presents a novel one-degree-of-freedom (1-DOF) single-loop reconfigurable 7R mechanism with multiple operation modes (SLR7RMMOM), composed of seven revolute (R) joints, via adding a revolute joint to the overconstrained Sarrus linkage. The SLR7RMMOM can switch from one operation mode to another without disconnection and reassembly, and is a non-overconstrained mechanism. The algorithm for the inverse kinematics of the serial 6R mechanism using kinematic mapping is adopted to deal with the kinematic analysis of the SLR7RMMOM. First, a numerical method is applied and an example is given to show that there are 13 sets of solutions for the SLR7RMMOM, corresponding to each input angle. Among these solutions, nine sets are real solutions, which are verified using both a computer-aided design (CAD) model and a prototype of the mechanism. Then an algebraic approach is also used to analyse the mechanism and same results are obtained as the numerical one. It is shown from both numerical and algebraic approaches that the SLR7RMMOM has three operation modes: a translational mode and two 1-DOF planar modes. The transitional configurations among the three modes are also identified

Parallel Manipulators

In recent years, parallel kinematics mechanisms have attracted a lot of attention from the academic and industrial communities due to potential applications not only as robot manipulators but also as machine tools. Generally, the criteria used to compare the performance of traditional serial robots and parallel robots are the workspace, the ratio between the payload and the robot mass, accuracy, and dynamic behaviour. In addition to the reduced coupling effect between joints, parallel robots bring the benefits of much higher payload-robot mass ratios, superior accuracy and greater stiffness; qualities which lead to better dynamic performance. The main drawback with parallel robots is the relatively small workspace. A great deal of research on parallel robots has been carried out worldwide, and a large number of parallel mechanism systems have been built for various applications, such as remote handling, machine tools, medical robots, simulators, micro-robots, and humanoid robots. This book opens a window to exceptional research and development work on parallel mechanisms contributed by authors from around the world. Through this window the reader can get a good view of current parallel robot research and applications

Formación emprendedora de la facultad de Ingeniería Química (FIQ) 2015-2018

In this article we present the experience of Entrepreneurial Training of the Facultyof Chemical Engineering (FIQ) 2015-2018 is presented, which had as purpose to develop skills, talents and entrepreneurial attitudes in the students, faculty and administrative staff of the faculty to contribute to its growth personal and professional. The process began in September 2015 and since then three generations have been trained, with a total of 152 participants, of which: 12 teachers, 6 administrative employees, 124 students from first to fifth year of the Chemical Engineering career and graduates of the FIQ, as well as 10 students participating in other UNI careers, stories such as industrial, mechanical, agricultural, civil and architectural engineering. Taking place in March 2018, the first Graduation of Entrepreneurs in which 32 certificates of approval of the Entrepreneurial Training course and Design of Business Plans were delivered, with the presentation of 11 completed business plans.En este artículo se presenta la experiencia de Formación Emprendedora de la Facultad de Ingeniería Química (FIQ) 2015-2018, que tuvo como propósito desarrollar habilidades, talentos y actitudes emprendedoras en los estudiantes, personal docente y administrativo de la facultad para contribuir a su crecimiento personal y profesional. El proceso inició en septiembre del año 2015 y desde entonces se han formado tres generaciones, capacitando a un total de 152 participantes de los cuales: 12 han sido docentes, 6 participantes del personal administrativo, 124 estudiantes de primer a quinto año de la carrera de ingeniería química y egresados de la FIQ, así como 10 estudiantes que pertenecen a otras carreras de UNI, tales como, ingeniería Industrial, mecánica, agrícola, civil y arquitectura. Realizándose en marzo de 2018, la primer Graduación de Emprendedores en la cual se entregaron 32 diplomas de aprobación del curso Formación Emprendedora y Diseño de Planes de Negocios, con la presentación de 11 planes de negocios concluidos

Grasping and Control Issues in Adaptive End Effectors

Research into robotic grasping and manipulation has led to the development of a large number of tendon based end effectors. Many are, however, developed as a research tool, which are limited in application to the laboratory environment. The main reason being that the designs requiring a large number of actuators to be controlled. Due to the space and safety requirements, very few have been developed and commissioned for industrial applications. This paper presents design of a rigid link finger operated by a minimum number of actuators, which may be suitable for a number of adaptive end effectors. The adaptive nature built into the end effector (due to limited number of actuators) presents considerable problems in grasping and control. The paper discusses the issues associated with such designs. The research can be applicable to any adaptive end effectors that are controlled by limited number of actuators and evaluates their suitability in industrial environments