A novel robotic leg design with hybrid dynamics

A new leg mechanism is designed to achieve optimal behaviour in both the stance and swing phases. The leg is designed such that its dynamics and kinematics optimally mimic those of simpler mechanisms, namely the spring-loaded inverted pendulum (SLIP) and the double pendulum, for the stance and swing phase, respectively. Controllers based on the simpler mechanisms can thus be used, resulting in an effective control strategy that is simple and transparent.     

星面探测仿生间歇式跳跃机器人设计及实现

设计了一种面向行星表面探测的小型间歇式仿生跳跃机器人.利用机构学中变胞思想及齿轮-连杆闭链机构的力转换特性,提出了一种杆长可控的非对称齿轮-六杆仿袋鼠跳跃机构,对其间歇式跳跃过程进行了分析,并针对跳跃能力和起跳躯干姿态平稳性进行了机构构型与尺寸优化设计.基于优化设计结果,进行了跳跃机器人运动仿真分析和样机试验.结果表明,该仿生跳跃机器人具有非线性递增的弹跳动力、平稳的起跳姿态以及较高的能量利用效率,可通过太阳能供电、单一微小电机驱动实现间歇式跳跃运动.     

Detection and tracking for robotic visual servoing systems

Robot manipulators require knowledge about their environment in order to perform their desired actions. In several robotic tasks, vision sensors play a critical role by providing the necessary quantity and quality of information regarding the robot's environment. For example, “visual servoing” algorithms may control a robot manipulator in order to track moving objects that are being imaged by a camera. Current visual servoing systems often lack the ability to detect automatically objects that appear within the camera's field of view. In this research, we present a robust “figureiground” framework for visually detecting objects of interest. An important contribution of this research is a collection of optimization schemes that allow the detection framework to operate within the real-time limits of visual servoing systems. The most significant of these schemes involves the use of “spontaneous” and “continuous” domains. The number and location of continuous domains are. allowed to change over time, adjusting to the dynamic conditions of the detection process. We have developed actual servoing systems in order to test the framework's feasibility and to demonstrate its usefulness for visually controlling a robot manipulator.     

基于能耗优化的六足机器人摆动腿轨迹规划

以六足机器人单腿为研究对象,研究机器人摆动腿轨迹规划问题.由于摆动要消耗能量,所以提出了一种基于能耗优化的轨迹规划方案.结合以D-H法建立的机器人单腿运动学模型和腿部位置、速度、加速度等约束,采用多项式插值法在关节空间对机器人摆动腿进行轨迹规划.在考虑直流电机有效功率和热损耗的基础上,通过遗传算法对非线性等式和不等式约束下的非线性规划问题进行求解.仿真结果表明,所设计的方案能有效降低摆动腿能量消耗并保证轨迹连续平滑.     

A fast directional filter set for pyramidal image-based robotic systems

In seeking to develop a real-time, pyramidal imaging system for tracking and robotic visual servoing applications, inadequacies in the standard, commonly available kernels for directional filtering have led to the implementation of an alternative set of simple filters that combine to act as oriented edge-contrast operators fulfilling the familiar requirements for both speed and a highly localized response pattern. Although numerous edge operators, kernels and directional filters have been proposed, and low-level filtering is a well-established and mature area of computer vision, within the application described here, this operator set is proving superior to more established methods in efficiently preserving the response localization requirement while propagating the oriented gradient energies through multichannel resolution pyramids for further recursive processing. This paper provides a detailed discussion of the technique, the context of its development, and supporting empirical tests and statistical results. The evidence presented shows that the scheme provides a unified response to both step and line edge types, with acceptable performance in the presence of anticipated noise levels. The approach is pragmatic, of low complexity, and of general utility.     

A new algorithm to maintain lateral stabilization during the running gait of a quadruped robot

This paper presents a new uncoupled controller (based on a Kinetic Momentum Management Algorithm, KMMA) which allows a quadrupedal robot, whose operation is simple and fast, to run using a symmetrical gait patterns in a wide variety of scenarios. It consists of two tasks: calculating the lateral position and speed of the fore swinging leg when it next makes contact with the ground; and controlling the roll angle by mean of inertia forces using the stance legs.The KMMA provides the benefits of modulation and the synchronization typically presented in CPG (Central Pattern Generation) models. Furthermore, it is able to maintain the locomotion parameters (such as stroke frequency of gait pattern) when the robot runs in a highly disturbed environment, thus resulting in a lower energy consumption. Additionally, the uncoupled scheme of the leg makes the operation computationally cheap, thus avoiding the use of a Virtual Actuator Control or a Hybrid Zero Dynamics.The performance of the KMMA has been verified by means of co-simulation (using ADAMS and MATLAB) with a highly realistic model of a quadruped robot with uncoupled legs. The performance of the algorithm has been tested in different situations in which the following variables have been varied: frontal velocity, turning ratio, payload, external disturbances and terrain slope. Successful results in terms of stability, energy efficiency, and adaptability to a complex locomotion environment have been obtained.     

Development of a mobile robotic system for working in the double-hulled structure of a ship

Shipbuilding processes involve highly dangerous manual welding operations. Welding ship walls inside double-hulled structures presents a particularly hazardous environment for workers. This paper describes the “Rail Runner X” (RRX), a new robotic system that can move autonomously inside the walls of a double-hulled ship and automatically execute the required welding processes. The RRX robotic system is composed of a mobile platform and a welding robot consisting of a 3P3R serial manipulator. The robot is used to weld U-shaped trajectories located between two longitudinal stiffeners. The mobile platform enables traverse movements onto neighboring longitudinal stiffeners. The entire cross section of the robotic system is small enough to be placed inside the double-hulled structure via a conventional access hole from the outside shipyard floor. The overall engineering design process that led to the final robot solution developed is presented in this paper, including kinematic analysis data and experimental results for verifying the autonomous movement and welding performance.     

A robust adaptive sliding-mode control for rigid robotic manipulators with arbitrary bounded input disturbances

In this paper, a robust adaptive sliding-mode control scheme for rigid robotic manipulators with arbitrary bounded input disturbances is proposed. It is shown that the prior knowledge on the upper bound of the norm of the input disturbance vector is not required in the sliding-mode controller design. An adaptive mechanism is introduced to estimate the upper bound of the norm of the input disturbance vector. The estimate is then used as a controller gain parameter to guarantee that the output tracking error asymptotically converges to zero and strong robustness with respect to bounded input disturbances can be obtained. A simulation example is given in support of the proposed control scheme.     

基于神经网络补偿的机器人滑模变结构控制

针对机器人控制系统中存在的建模误差和不确定性干扰,提出了基于神经网络补偿的滑模变结构控制。该方法采用双幂次快速终端滑模控制使得系统能在有限时间内快速达到滑模面和平衡点,采用径向基函数神经网络自适应地补偿建模误差和不确定干扰,并通过李雅普诺夫直接法设计权值更新率,确保了系统的全局稳定性,有效抑制了抖震。对两关节机器人的仿真结果表明了该方法的有效性。     

A distributed control scheme for multiple robotic vehicles to make group formations

This paper presents a novel distributed control scheme of multiple robotic vehicles. Each robotic vehicle in this scheme has its own coordinate system, and it senses its relative position and orientation to others, in order to make group formations. Although there exists no supervisor and each robotic vehicle has only relative position feedback from the others in the local area around itself, all the robotic vehicles are stabilized, which we have succeeded in proving mathematically only in the cases where the attractions between the robots are symmetrical. Each robotic vehicle especially has a two-dimensional control input referred to as a “formation vector” and the formation is controllable by the vectors. The validity of this scheme is supported by computer simulations.     

The general architecture of adaptive robotic systems for manufacturing applications

Adaptive system often refers to the adaptive control system. In this paper, we discuss the adaptive system concept from an architectural perspective of the system. We use the robotic system as an example to illustrate the adaptive system concept, because the robotic system is a generic system underlying many manufacturing systems. Specifically, the paper presents our work on the development of a general architecture of the adaptive robotic system for manufacturing applications. The contribution of this paper includes: (i) elaboration of the concept of adaptive system and classification of means to make the system adaptive and (ii) formulation of a general architecture of the adaptive robotic system based on the criterion that the more system variants out of the architecture implies the more generality of the architecture. Throughout this paper, we use an industrial robotic system for illustration.     

含弧形自由度仿人灵巧手掌的机构设计

提出了一种人手掌的简化模型,根据该模型,设计了仿人灵巧手掌的机构,使得只作为仿人灵巧手手指及其控制部件机架的手掌形成弧形自由度参加手部动作,提高了仿人灵巧手通用性、灵活性和抓持物体的适应性。经优化设计和仿真,机构完全符合灵巧手进行运动时手掌的运动要求。     

Design,implementation and validation of a stability model for articulated autonomous robotic systems

The use of robots in agriculture and forestry is rapidly growing thanks to the progress in sensors, controllers and mechatronics devices. Especially in hilly and mountainous terrains, the development of (semi-)autonomous systems that could travel safely on uneven terrain and perform many operations is an open field of investigation. One of the most promising mobile robot architectures is the articulated 4-wheeled system that shows an optimal steering capacity, and the possibility to adapt to uneven terrains thanks to a central passive degree of freedom. In this paper, the kinematic and (quasi-)static model for evaluating the phase I instability presented in Baker and Guzzomi(2013) has been firstly extended to allow to threat a generic articulated robotic system and to forecast the instability conditions. Then, the model and the stability conditions have been implemented in a Matlab™ simulator and validated by means of an experimental emulator. Finally, a first prototype for a mechatronic anti-overturning device is discussed.     

A gait study for a one-leg-disabled hexapod robot

—As a remarkably strong point of a hexapod walking robot, it is considered that even if one of the six legs is disabled, static walking may be maintained by the remaining five legs. However, to maintain the static stability at maximum, a gait study for five-legged walking is a necessary factor. Hence, this paper describes a method of gait study for such a situation. Since it is very difficult to find a suitable gait by use of an analytical method without any model, such as a model based on insects' walking, we employed a programming method with the help of recent powerful computers. Some devices are applied to reduce the number of computations. As a result, we have obtained two kinds of gaits which can maintain the gait stability margin at a high level for a duty factor in the range of 0.6β < 1.     

Efficient force distribution and leg posture for a bio-inspired spider robot

Legged walking and climbing robots have recently achieved important results and developments, but they still need further improvement and study. As demonstrated by recent works, bio-mimesis can lead to important technical solutions in order to achieve efficient systems able to climb, walk, fly or swim (Saunders et al., 2006 [36], Ayers, 2001 [25], Safak and Adams, 2002 [26]). In this paper, taking into account the anatomy and the adhesive and locomotion capabilities of the spider (i.e., an eight-legged system), we present on the one hand a study of the foot force and torque distribution in different operative and slope conditions and, on the other hand, a posture evaluation by comparing different leg configurations in order to minimize the torque effort requirements.     

连续电驱动四足机器人腿部机构设计与分析

提出了一种四足机器人腿部的连续电驱动（即电机整周转动驱动腿部实现摆转跨步动作）方案,设计了一种具有由切比雪夫机构、五杆机构组成的2自由度双曲柄复合连杆机构的机器人腿部结构．分析了动物的足端轨迹特性,采用轨迹圆滑、无突变、导数连续的椭圆曲线规划了机器人足端运动轨迹．以规划的足端轨迹再现为优化目标,采用遗传算法与fmincon函数内点法计算得到了腿部机构杆长的最佳尺寸．在此基础上,建立了机器人仿真模型,通过Adams仿真分析了机器人腿部机构的足端运动特性,并研制了腿部结构性能测试平台．完成了单腿足端运动轨迹跟踪实验,验证了腿部结构设计方案的可行性．     

一种小型陆空两栖机器人的选型分析与结构设计

为了适应灾害救援、资源勘探、野外侦查等复杂作业、复杂场景、复杂地形产生的特殊需求,文章研究了一种小型陆空两栖机器人的总体构型及其结构设计。首先根据该机器人要能实现陆地低角度侦查和空中高角度侦查的使用需求,确定该机器人要兼具地面运动能力和空中运动能力,其功能是地面机器人和飞行机器人的有机结合,据此分别探讨了一体式和组合式两种设计方案,进行了机构的构型分析[1]。在一体式构型方案中,对两自由度结构腿和三自由度结构腿分别进行了阐述与分析。最后综合对比了一体式构型方案和组合式构型方案,通过对优缺点的综合对比,得出组合式构型方案在功能性、实用性和稳定性等方面具有明显优势,为该机器人物理样机的研制提供了可靠、可信的依据[2]。     

Progress towards robotic exploration of extreme terrain

A high degree of mobility, reliability, and efficiency are needed for autonomous exploration of extreme terrain. These requirements have guided the development of the Ambler, a six-legged robot designed for planetary exploration. To address issues of efficiency and mobility, the Ambler is configured with a stacked arrangement of orthogonal legs and exhibits a unique circulating gait, where trailing legs recover directly from rear to front. The Ambler is designed to stably traverse a 30 degree slope while crossing meter sized features. The same three principles have provided many constraints on the design of a software system that autonomously navigates the Ambler through natural terrain using 3-D perception and a combined deliberative/reactive architecture. The software system has required research advances in real-time control, perception of rugged terrain, motion planning, task-level control, and system integration. This paper presents many of the factors that influenced the design of the Ambler and its software system. In particular, important assumptions regarding the mechanism, perception, planning, and control are presented and evaluated in light of experimental and theoretical research of this project.     

Design of a low-cost five-finger anthropomorphic robotic arm with nine degrees of freedom

The aim of this work was to design and demonstrate a dexterous anthropomorphic mobile robotic arm with nine degrees of freedom using readily available low-cost components to perform different object-picking tasks for immobile patients in developing nations. The robotic arm consists of a shoulder, elbow, wrist and five-finger gripper. It can perform different gripping actions, such as lateral, spherical, cylindrical and tip-holding gripping actions using a five-finger gripper; each finger has three movable links. The actuator used for the robotic arm is a high torque dc motor coupled with a gear assembly for torque amplification, and the five-finger gripper consists of five cables placed like tendons in the human arm. The robotic arm utilizes a controller at every link to trace the desired trajectory with high accuracy and precision. Digital implementation of the control algorithm is done on an Atmel Atmega-16 microcontroller using trapezoidal approximation and Newton's backward difference methods. The arm can be programmed or controlled manually to perform a variety of object-picking tasks. A prototype of the robotic arm was constructed, and test results on a variety of object-picking tasks are presented.