Dynamic Modeling and Analysis of the Human Jumping Process

Humanoid robots have recently been the subject of many new and interesting fields both in robotics research and industry. The wide variety of their applications in civic and hostile environments demand developing approperiate theoretical models for analysis. A dynamical model was developed to study the human jumping process, and the effect of factors like joint speeds and hand motion in jumping. An experiment was designed and setup to compare the theoretical model with experimental observations. Time histories of vertical force, mass center velocity and driving torques were also obtained. Using dynamical equations, the effect of joint speeds on the maximum values of these quantities is discussed. It was shown that reducing the joint speeds of a body could lead to an unsuccessful jump in which the body would not enter the flight phase. An increase in speed reduced the take-off time (the time necessary for the body to leave the ground) and increased the body's linear velocity at take-off, as well as the maximum value of driving torques. Effect of hand motion was also investigated through suppressing motion of the shoulder and elbow. It was observed that hand motion had an improving effect on the body's linear velocity. Although speed of joints did not show to have a great influence on most joint torques, those at the shoulder and elbow were observed to be more sensitive to it.     

Data Communications for Internet Robots

For Internet robots, the most challenging and distinct difficulties are well recognized to be associated with Internet transmission delays, delay jitter and not-guaranteed bandwidth, which might degrade system performance dramatically or even lead to instability. Current approaches to data communication between the remote robot and the human operator employ directly one of the two currently available protocols, i.e. TCP and UPD. In this paper, a teleoperation-oriented data transmission mechanism is implemented. Compared to TCP, the presented scheme provides minimized transmission delays and delay jitter; in the steady state, its transmission rate is much smoother; when available network bandwidth changes, it adapts to the variation quickly without large overshoot. Compared to UDP, it is inter-protocol fairness convergent, intro-protocol convergent, and efficient convergent. The presented mechanism is deployed in a mobile robot teleoperation system developed. In the experiments, users successfully guided a Pioneer-2 mobile robot through a laboratory environment remotely over the Internet via a web browser.     

双机器人协调作业下碰撞算法及仿真研究

本文立足于关节水平，从双机器人碰撞研究入手，提出了机器人协同作业下碰撞检测 、干涉空间的算法，解决了机器人与周边环境任意障碍物碰撞问题．建立了连杆与连杆，连 杆与平面，连杆与任意三维实体避障理论模型，给出了相应的计算方法及计算机仿真结果．     

一种基于概率方法的车型机器人路径规划方法

考虑车体外形和前轮方向角限制,车型移动机器人路径的空间维数明显增加,常规的规划方法难以获得理想的速度。论文报告了概率方法在车型机器人路径规划上的研究结果,共研究了机器人约束、全局、局部概率路径规划和启发式结点生成等问题。模拟表明,该方法可获得足够好的适合车型机器人移动的次优路径。     

基于专家系统的多移动机器人模糊自校正协调系统

研究多移动机器人的运动规划问题，在实时运动规划专家系统的基础上提出了一种串级模糊控制器，以校正实际工作环境下各机器人的运动状态与理想情况下可能产生的误差，使各机器人正确调整各自运动状态，达到协调工作的目的。     

Training a Vision Guided Mobile Robot

This paper presents the design, implementation and evaluation of a trainable vision guided mobile robot. The robot, CORGI, has a CCD camera as its only sensor which it is trained to use for a variety of tasks. The techniques used for training and the choice of natural light vision as the primary sensor makes the methodology immediately applicable to tasks such as trash collection or fruit picking. For example, the robot is readily trained to perform a ball finding task which involves avoiding obstacles and aligning with tennis balls. The robot is able to move at speeds up to 0.8 ms^-1 while performing this task, and has never had a collision in the trained environment. It can process video and update the actuators at 11 Hz using a single $20 microprocessor to perform all computation. Further results are shown to evaluate the system for generalization across unseen domains, fault tolerance and dynamic environments.     

Robust Hybrid Control of Constrained Robot Manipulators via Decomposed Equations

Basing on a constraint Jacobian induced orthogonal decomposition of the task space and by requiring the force controller to be orthogonal to the constraint manifold, the dynamics of the constrained robots under hybrid control is decomposed into a set of two equations. One describes the motion of robots moving on the constraint manifold, while the other relates the constraint force with the hybrid controller. This decomposition does not require the solution of the constraint equation in partition form. In this setting, the hybrid control of constrained robots can be essentially reduced to robust stabilization of uncertain nonlinear systems whose uncertainties do not satisfy the matching condition. A continuous version of the sliding-mode controller (from Khalil [12]) is employed to design a position controller. The force controller is designed as a proportional force error feedback of high gain type. The coordination of the position controller and the force controller is shown to achieve ultimately bounded position and force tracking with tunable accuracy. Moreover, an estimate of the domain of attraction is provided for the motion on the constraint manifold. Simulation for a planar two-link robot constraining on an ellipse is given to show the effectiveness of a hybrid controller. In addition, the friction effect, viewed as external disturbance to the system, is also examined through simulations.     

Rough Terrain Autonomous Mobility—Part 1: A Theoretical Analysis of Requirements

A basic requirement of autonomous vehicles is that of guaranteeing the safety of the vehicle by avoiding hazardous situations. This paper analyses this requirement in general terms of real-time response, throughput, and the resolution and accuracy of sensors and computations. Several nondimensional expressions emerge which characterize requirements in canonical form.The automatic generation of dense geometric models for autonomously navigating vehicles is a computationally expensive process. Using first principles, it is possible to quantify the relationship between the raw throughput required of the perception system and the maximum safely achievable speed of the vehicle. We derive several useful expressions for the complexity of terrain mapping perception under various assumptions. All of them can be reduced to polynomials in the response distance.The significant time consumed by geometric perception degrades real-time response characteristics. Using our results, several strategies of active geometric perception arise which are practical for autonomous vehicles and increasingly important at higher speeds.     

A Probabilistic Approach to Concurrent Mapping and Localization for Mobile Robots

This paper addresses the problem of building large-scale geometric maps of indoor environments with mobile robots. It poses the map building problem as a constrained, probabilistic maximum-likelihood estimation problem. It then devises a practical algorithm for generating the most likely map from data, along with the most likely path taken by the robot. Experimental results in cyclic environments of size up to 80 by 25 meter illustrate the appropriateness of the approach.