Centroidal-momentum-based trajectory generation for legged locomotion

This paper presents a trajectory optimization framework for planning dynamic legged locomotion based on a robot’s centroidal momentum (CM), which is the aggregation of all the links’ momenta at the robot’s Center of Mass (CoM). This new framework is built around CM dynamic model driven by Ground Reaction Forces (GRFs) parameterized with Bézier polynomials. Due to the simple form of CM dynamics, the closed-form solution of the robot’s CM can be obtained by directly integrating the Bézier polynomials of GRFs. The CM can be also calculated from the robot’s generalized coordinates and velocities using Centroidal Momentum Matrices (CMM). For dynamically feasible motions, these CM values should match, thereby providing equality constraints for the proposed trajectory optimization framework. Direct collocation methods are utilized to obtain feasible GRFs and joint trajectories simultaneously under kinematic and dynamic constraint. With the closed-form solutions of CM due to the parameterization of GRFs in the formulation, numerical error induced by collocation methods in the solution of trajectory optimization can be reduced, which is crucial for reliable tracking control when applied to real robotic systems. Using the proposed framework, jumping trajectories of legged robots are obtained in the simulation. Experimental validation of the algorithm is performed on a planar robot testbed, proving the effectiveness of the proposed method in generating dynamic motions of the legged robots.     

Generalisation of the bandpass-lowpass analogy and its application to a phase-shift-keying signal

The conventional theory of the bandpass-lowpass analogy has been generalised to include a frequency-modulated signal. As an example, the explicit formulas are derived for the output wave of a phase-shift-keying signal when it passes through a single-tuned bandpass filter.     

机电一体化技术和应用研究初探

讨论了机电一体化技术对于改变整个机械制造业面貌所起的重要作用,并说明其在钢铁工业中的应用以及发展趋势。     

MECHATRONICS 2000. Seventh Mechatronics Forum InternationalConference and Mechatronics Education Workshop

The following topics are dealt with: flip chip solder joint quality inspection; direct chip attach packaging for microsystems; reliability analysis of no-underfill flip chip package; ASIC/memory integration by system-on-package; wafer-level and flip chip designs through solder prediction models and validation; reliability evaluation of under bump metallurgy in two solder systems; a method to improve the efficiency of the CMP process; thermal and reliability analysis of packaging systems     

Mechatronics applied to auditory localisation for telepresence

This paper describes the importance of the sense of hearing for immersive telepresence systems, and a fundamental approach to designing and implementing a binaural sensor system. This approach relies on knowledge of how the human auditory localisation mechanisms work to locate sounds in space, in order that a synthetic system can be derived. The most important of these mechanisms are explained. The Strathclyde auditory system is then described including ideas drawn from the literature to define a binaural approach. This novel system consists of a set of artificial pinnae and microphones mounted on a binocular stereo sensor platform capable of pan, tilt and roll which is slaved to a head tracking system. A set of preliminary experiments is described which test the performance of the system in practice, as a basis for further development.     

从模拟电视到数字电视的跨越

模拟电视向数字电视过渡是技术发展的必然趋势 ,如果我国对数字电视产业化发展的战略和策略得当 ,那么 ,我国模拟电视产业就能平稳过渡为可持续自主发展的数字电视产业 ,并带动其基础产业 (系统和整机、专用集成电路和芯片、关键部器件特别是显示器件等 )和相应的软件产业及系统集成 (如嵌入式操作系统、中间件和应用软件等 )的健康发展。 1992年以来 ,我国政府开始组织对数字高清晰度电视的科技攻关项目 ,并已经取得了丰硕成果 ,我国正面临模拟电视向数字电视过渡的关键时期。1　数字电视1.1　数字电视的定义数字电视系统是将活动图像、声…     

Design and control of the rapid legged platform GAZELLE

This study presents the design and system integration of the 13-degree-of-freedom legged platform, GAZELLE. The goal of this research is to develop a fast and reliable biped platform for walking experiments. Rapid leg movement can increase robustness in walking stability. During external push or walking on uneven ground, fast leg movement can realize an abrupt change on the landing position. GAZELLE is characterized by a lightweight design, a link-driven structure for low leg inertia, a wide range of motion, and a direct-stacked fin air-cooling module. The actuator is designed using a special type of harmonic drive (lightweight CSF type) and a 200 W brushless DC motor with high power density. The knee and ankle joints are link-driven; hence, the actuators can be placed on the upper position, and the leg inertia is reduced. A novel air cooler design for the cylinder-type motor, which is extremely light and highly efficient, is introduced herein and realized by stacking cooling fins to the motor housing. This study also includes a brief introduction of a stabilizing controller and the walking experiment results of GAZELLE.     

机电一体化课程的仿真设计

机电一体化技术课程设计是机电一体化专业的实践课程。应用仿真软件,设计自动控制程序,丰富课程设计的内容。通过增加机电一体化设计的仿真设计环节,使学生的机电结合的知识更加巩固,同时对相关知识的理解也更趋向于立体化。这样的仿真环节,对同样有此课程的同行们,会有一定的启示作用。     

Towards stable and efficient legged race-walking of an ePaddle-based robot

ePaddle mechanism is a novel hybrid locomotive mechanism designed for accessing terrestrial, aquatic and amphibious terrains with versatile locomotion gaits. Among those gaits, race-walking gait has a promised gait that is potential for achieving highly stable, and highly energetic efficient legged walking. This paper studies the motion planning method of this unique race-walking gait for an ePaddle-based quadruped robot. The standard gait sequence that consists of four phases is firstly presented. The selection of wheel-center trajectory for achieving the gait is then discussed based on kinematic models of the ePaddle module in these phases. Two motion planning methods are presented for an ePaddle-based quadruped robot to track planar path with the proposed race-walking gait. Stability and energetic performances of the proposed race-walking gait are discussed by evaluating duty factor of the ePaddle module, and by measuring stability margin and specific resistance of the robot. A set of simulations on tracking straight and circular paths verifies the idea of the race-walking gait as well as its stability and efficiency.     

Guest Editorial Introduction to the Focused Section on Medical Mechatronics

The six papers in this focused section were originally presented at the first IEEE/RAS-EMBS International Conference on Biomedical Robotics and Biomechatronics (BioRob'06), held February 20-22, 2006, in Pisa, Italy. The first three papers illustrate mechatronic devices for rehabilitation applications; the fourth paper presents a mechatronic system for disabled people; and the last two papers deal with mechatronic devices and technologies for minimally invasive and teleoperated surgery. The papers are summarized here.     

Understanding air-core photonic-bandgap fibers: analogy to conventional fibers

It is shown from basic principles that the core modes of an air-core photonic-bandgap fiber (PBF) exhibit similar qualitative and quantitative behavior as the linearly polarized (LP) modes of an equivalent conventional fiber whose step-index profile is entirely determined by the band edges of the PBF. This analogy leads to the concept of effective numerical aperture (NA), which is used to provide an intuitive interpretation of the qualitative behavior of PBF modes. By using this equivalence, several key properties, including the number of modes, their cutoff, effective index, size, and divergence, and the dependence of these quantities on the PBF core and cladding parameters, can be predicted approximately by simulating the LP modes of the equivalent step-index fiber using standard LP-mode simulators or well-known formula. Besides providing a convenient tool to model the modes of a PBF, this analogy gives new physical insight into the fundamental characteristics of these complex waveguides.     

Guest Editorial Introduction to the Focused Section on Advanced Integrated Mechatronics

The 11 regular papers and four short papers in this special section focus on the research issues of advanced integrated mechatronics. The topics include advanced mechatronic sensing, devices and control, biomechatronics for better life, intelligent mechatronic systems, infotronics-enabled mechatronics systems, intelligent automation systems, and innovative applications of mechatronic systems.     

传感器与检测技术在机电一体化系统中的应用

通过对传感器及检测技术在机电一体化系统中应用状况的描述,指出传感器及检测技术作为机电一体化系统不可缺少的关键技术之一,在机电一体化系统中起着举足轻重的地位和作用,也是机电一体化系统完成自动控制和自动调节的关键环节。同时还对机电一体化系统中常用传感器的种类、功能、以及将来的研究、应用和发展方向做了简要介绍。     

Guest Editorial Introduction to the Focused Section on Mechatronics in Multirobot Systems

This Focused Section includes ten papers that cover advances in mechatronics that are applicable to multirobot systems. The introduction also includes highlights of related articles published in previous issues of the IEEE/ASME Transactions on Mechatronics.     

Mechatronics and control of a long-range nanometer positioning servomechanism

Since the manufacturing accuracy of semiconductor and biochemical products is increased to nanometer level gradually, the development of long-range positioning servomechanism has become a hot research topic. The piezoelectric actuator is widely chosen to design precise positioning system for achieving the sub-micro or nano-position. However, their motion range is only 100 μm. Here, a long-range nanometer positioning servo system with AC servo motor and ball screw mechanism is built for the precision manufacturing purpose. It needs a special design control algorithm to obtain quick transient response and precise steady state accuracy. A new model-free fuzzy controller is designed to control this low-cost motion stage for achieving nanometer step response positioning. It has a novel gain auto-tuning strategy in response to the transient or steady state responses requirement. The experimental results show that this approach can reach more than 30 cm stroke and the step response error is less than 60 nm.