Motor systems: reaching out and grasping the molecular tools.

Two recent studies provide important insights into the organization of premotor circuitries, showing that control of highly-specific skilled forelimb movements, such as reaching and grasping, requires activation of specific subpopulations of neurons in the brainstem and spinal cord.

Trial Test of a Bulk-Type Fully HTS Synchronous Motor

© 2013 IEEE. The world's first bulk-type fully high temperature superconducting synchronous motor (HTS-SM) was assembled and tested in our laboratory at the University of Cambridge. The fully HTS-SM was designed with 75 Y123 HTS bulks mounted on the surface of the rotor and six air core 2G HTS racetrack coils used for stator windings. We successfully applied a light fan load test for this fully HTS-SM at its operating temperature of 77 K. The detected decay of the trapped magnetic flux densities at the centre of the HTS bulks was up to 16.5% after 5 h of synchronous rotation. Due to the high current density of the HTS material, the ac stator field for the 2G HTS winding was 49.2% stronger compared with a comparable copper winding. In the meantime, we estimated that the efficiency was about 86% potentially under stable low frequency rotation at 150 r/min. The results show that the performance of this HTS motor is acceptable for practical applications.

Self-organization of reflexive behavior from spontaneous motor activity.

In mammals, the development of reflexes is often regarded as an innate process. However, recent findings show that fetuses are endowed with favorable conditions for ontogenetic development. In this article, we hypothesize that the circuitry of at least some mammalian reflexes can be self-organized from the sensory and motor interactions brought forth in a musculoskeletal system. We focus mainly on three reflexes: the myotatic reflex, the reciprocal inhibition reflex, and the reverse myotatic reflex. To test our hypothesis, we conducted a set of experiments on a simulated musculoskeletal system using pairs of agonist and antagonist muscles. The reflex connectivity is obtained by producing spontaneous motor activity in each muscle and by correlating the resulting sensor and motor signals. Our results show that, under biologically plausible conditions, the reflex circuitry thus obtained is consistent with that identified in relation to the analogous mammalian reflexes. In addition, they show that the reflex connectivity obtained depends on the morphology of the musculoskeletal system as well as on the environment that it is embedded in.

Motor control optimization of compliant one-legged locomotion in rough terrain

While underactuated robotic systems are capable of energy efficient and rapid dynamic behavior, we still do not fully understand how body dynamics can be actively used for adaptive behavior in complex unstructured environment. In particular, we can expect that the robotic systems could achieve high maneuverability by flexibly storing and releasing energy through the motor control of the physical interaction between the body and the environment. This paper presents a minimalistic optimization strategy of motor control policy for underactuated legged robotic systems. Based on a reinforcement learning algorithm, we propose an optimization scheme, with which the robot can exploit passive elasticity for hopping forward while maintaining the stability of locomotion process in the environment with a series of large changes of ground surface. We show a case study of a simple one-legged robot which consists of a servomotor and a passive elastic joint. The dynamics and learning performance of the robot model are tested in simulation, and then transferred the results to the real-world robot. ©2007 IEEE.

Standing up with motor primitives

As observed in nature, complex locomotion can be generated based on an adequate combination of motor primitives. In this context, the paper focused on experiments which result in the development of a quality criterion for the design and analysis of motor primitives. First, the impact of different vocabularies on behavioural diversity, robustness of prelearned behaviours and learning process is elaborated. The experiments are performed with the quadruped robot MiniDog6M for which a running and standing up behaviour is implemented. Further, a reinforcement learning approach based on Q-learning is introduced which is used to select an adequate sequence of motor primitives. © 2006 Springer-Verlag Berlin Heidelberg.

Roles of Knowledge in Motor Learning

The goal of this thesis is to apply the computational approach to motor learning, i.e., describe the constraints that enable performance improvement with experience and also the constraints that must be satisfied by a motor learning system, describe what is being computed in order to achieve learning, and why it is being computed. The particular tasks used to assess motor learning are loaded and unloaded free arm movement, and the thesis includes work on rigid body load estimation, arm model estimation, optimal filtering for model parameter estimation, and trajectory learning from practice. Learning algorithms have been developed and implemented in the context of robot arm control. The thesis demonstrates some of the roles of knowledge in learning. Powerful generalizations can be made on the basis of knowledge of system structure, as is demonstrated in the load and arm model estimation algorithms. Improving the performance of parameter estimation algorithms used in learning involves knowledge of the measurement noise characteristics, as is shown in the derivation of optimal filters. Using trajectory errors to correct commands requires knowledge of how command errors are transformed into performance errors, i.e., an accurate model of the dynamics of the controlled system, as is demonstrated in the trajectory learning work. The performance demonstrated by the algorithms developed in this thesis should be compared with algorithms that use less knowledge, such as table based schemes to learn arm dynamics, previous single trajectory learning algorithms, and much of traditional adaptive control.

Motor Control and Learning by the State Space Model

A model is presented that deals with problems of motor control, motor learning, and sensorimotor integration. The equations of motion for a limb are parameterized and used in conjunction with a quantized, multi-dimensional memory organized by state variables. Descriptions of desired trajectories are translated into motor commands which will replicate the specified motions. The initial specification of a movement is free of information regarding the mechanics of the effector system. Learning occurs without the use of error correction when practice data are collected and analyzed.

Aprendizaje integrado de Epidemiología y Bioestadística en el Grado de Medicina: valoración de los estudiantes

Los objetivos fueron conocer la valoración de los alumnos de 2º de Medicina sobre la inte-gración Epidemiología-Bioestadística y comparar su percepción a comienzo y final de curso. Se elaboraron dos cuestionarios con afirmaciones que los alumnos valoraron mediante una escala tipo Likert. Participaron 102 estudiantes. Para comparar los resultados a principio y final de curso se utilizó la prueba de rangos con signo de Wilcoxon. El 83% creía al finalizar el curso que comprendían la importancia de Epidemiología-Bioestadística en Medicina y les parecía interesante estudiarlas de forma integrada. Al inicio de curso, un 46,1% pensaba que la asignatura iba a ser interesante y al final este porcentaje fue 69,6%. Al inicio, el 69,6% veía la relación entre la Medicina y la Estadística y al final, el 83,3%. El 41% creía al inicio que iban a adquirir competencias fundamentales para el desempeño profesional y al final lo creía el 57,8%.

Las exposiciones orales como herramienta para mejorar el clima de aprendizaje

En el marco de un proyecto de investigación-acción sobre las actitudes de los profesores y su influencia en el clima de aprendizaje, llevamos a cabo un procedimiento para mejorar dicho clima durante la realización de exposiciones orales, de trabajos realizados en pequeños grupos. Concluida la exposición tanto los alumnos que habían expuesto como sus compañeros realizaban una valoración crítica. Todos los comentarios fueron recogidos por escrito y se utilizaron para elaborar un documentoguía para la realización de exposiciones orales. Participaron 106 estudiantes de la Universidad Europea de Madrid. Se diseñó un cuestionario para conocer la valoración de los estudiantes sobre la actividad, que fue cumplimentado por 87 alumnos. Aunque la mayoría de los participantes había realizado exposiciones orales previamente, el 39,1% se mostraba “en desacuerdo” o “totalmente en desacuerdo” en haber recibido pautas para hacer correctamente una presentación y exposición oral. El 92% de ellos consideraron importante para mejorar sus exposiciones el recibir formación al respecto. El 89,6% estaban “de acuerdo” o “totalmente de acuerdo” en que la actitud del profesor durante la actividad fue adecuada. El 65,5% consideraron que la actividad favoreció un clima de colaboración y compañerismo.

Aprendizaje experiencial aplicado en la enseñanza superior en el campo de la electrónica en cursos para adultos trabajadores

En este trabajo se muestran las experiencias tenidas con adultos trabajadores en la enseñanza de la Electrónica, en la formación de los mismos como Ingenieros. Están basadas en el aprendizaje experiencial, desde el primer encuentro, gracias a las vivencias obtenidas por el propio alumno, se aprecian ventajas en la aplicación de esta metodología que dan respuesta a las necesidades de este tipo de alumno. Así estos alumnos optimizan el tiempo necesario de aprendizaje, facilitando la comprensión, aplicación y justificación de los conocimientos teóricos. Les reafirma la confianza en sí mismos y les facilita el acercamiento con su vida profesional.

Growth of Motor Coordination in Early Robot Learning

M. H. Lee and Q. Meng, Growth of Motor Coordination in Early Robot Learning, IJCAI-05, 2005.

A Content-Neutral Approach for Sensory-Motor Learning in Developmental Robotics

M.H. Lee, Q. Meng and F. Chao, 'A Content-Neutral Approach for Sensory-Motor Learning in Developmental Robotics', EpiRob'06: Sixth International Conference on Epigenetic Robotics, Paris, 55-62, 2006.