Stereo-vision plays an important part in planetary exploration. A high-precision calibration method is introduced for such system, which uses wide-angle lens. It makes use of planar homography constraint to estimate intrinsic and extrinsic parameters. On the basis of this initial guess, an optimization scheme is used to minimize a new cost function, 3D reprojection error sum. All calibration parameters of two cameras are globally optimized simultaneously with genetic algorithm (GA). Both simulation and real image experiment results show this scheme have much higher precision than traditional methods

The paper analysis a kinematic model for a wheeled mobile robot (WMR) traversing uneven terrain. A new form of the kinematics for wheeled mobile robot is deduced, through analyzing Jacobian matrices of individual wheel and rearranging the variables. The performance and characters of the kinematic formulation are explained using physical conception. A new method is proposed to set up the kinematics formulation for wheeled mobile robots. After analyzing the actuation kinematics, simulation results are provided to validate the motion of wheeled mobile robot over a special terrain

In this paper, a high order open and closed ILC (iterative learning control) scheme with initial state learning is presented. The convergent bounds are only dependent on the system uncertainties and disturbances but independent of the initialization errors. The scheme performs better than common ILC scheme with initial state learning both in convergence rate and transient performance. By adding closed loop, the whole algorithm has better performance in both stability and convergence than the open loop one alone. Furthermore, the effectiveness of the proposed method is illustrated by simulation experiments.

This paper presents an iterative learning scheme for a linear time-invariance (LTI) system. Based on the scheme, the influence of learning structure, learning laws and learning parameters on the convergence speed of iterative learning control (ILC) is discussed. Furthermore, the theoretical proof and simulation conclusions are provided, which is the theoretical instruction and designing guideline for practical applications of ILC.

This paper focuses on motion planning in dynamic environments that exists dynamic obstacle and moving goal. It is based on the relative coordinates and acceleration space coordinates and it includes two behaviors: obstacle avoidance and moving to the goal. The behavior of avoidance is reactive, and the behavior of moving to the goal is considered as a reverse problem of the avoidance. The switch between two behaviors is based on the acceleration space coordinates. The experiment results verify its validity.

It is an important problem to determine the relative position and translation between two space objects in robotic research. However, if traditional stereo vision method is used in model-based system without exploiting rigid constraints, the precision may be low especially in depth direction. This paper solves this problem with an accurate and real-time strategy, which is based on real-time genetic algorithm (RGA) and perspective 3-point (P3P) algorithm. Real image and simulation experiments show this method has dramatic performance and it can be applied in real-time situation.

This paper describes the motion planning problems of mobile robots in uncertain dynamic environments with no restrictions on the shape of obstacles. A new approach based on the behavior dynamics of collision-avoidance is proposed to deal with the real-time collision-free motion planning using the local coordinates of the mobile robot. The behavior dynamics of a dynamic collision-avoidance process was modeled, and then the motion-planning problem was transformed into a simple optimization problem with some inequality constraints based on control of the behavior dynamics. The decision-making space of this optimization problem is right the acceleration space of the mobile robot. By solving this optimization problem, the optimal behavior of the mobile robot to avoid obstacles and go to the desired target can be obtained easily. Simulations are given to illustrate the main ideas.

This paper proposes a calibration strategy for distorted camera with high precision. It makes use of planar homography constraint to estimate the intrinsic and extrinsic parameters. On the basis of this initial guess, an optimization scheme is used to minimize a new cost function, which is based on a perspective 3-point (P3P) algorithm. All the calibration parameters are globally optimized simultaneously with genetic algorithm (GA). Simulation and real image experiment result show this technique have much higher precision than traditional methods.

The network-included delays are not only unknown and stochastic, but also usually more than one sampling interval, which result in disturbing the order of control signals and making the system analysis much complex. By the prediction of a new estimator and using the event-driven and time-driven actuators simultaneously, the plant gets the current control signals in every sampling interval. Thus, the long delays are compensated in time. The simulation results show the efficiency of this compensation method.

Now a number of advanced control systems take advantage of networks such as Ethernet, Fieldbus and Internet as their communication channel. Transmission time delay of these networks may lead unstable problems to system. In this paper, the prediction of network delay using neural network is presented first. Then the analysis of the control oriented quality of service (CO-QoS) specially with the Internet-based teleoperation is considered and fuzzy inference is used to construct a quantification of CO-QoS. At last, the simulation results show that this method provides a practical way for the judgment of the network's characteristics.

Classical PD control for a direct drive motor system is enhanced to suppress disturbing torque by incorporating an acceleration feedback loop. This is intended to achieve a stable and high stiffness control without the need of adjusting the PD controller, either the structure or the parameters. The acceleration feedback control is presented with a focus on designing the acceleration closed-loop in terms of its stability and ability in resisting the dynamic disturbances. The sensing and modeling of angular acceleration via servo-type linear accelerometers is dealt with from the viewpoint of practical implementation. Extensive experiments are conducted on the second joint of a three-link direct drive robot. Results are compared to those obtained by classical PD control without the acceleration feedback loop, to mainly investigate the ability of the acceleration feedback control in resisting disturbing torque, and its influence on conventional PD control.

This paper is concerned with the stabilization problem of multiple chained form control systems with input constraints. A new controller presented can stabilize the system to an arbitrarily, small /spl epsi/-neighborhood of its equilibrium in a finite time. This is achieved by the sliding mode approach and a multi-step control strategy. The application of it to a nonholonomic wheeled mobile robot is described. Simulation result shouts that the proposed controller is effective.

In this paper, a ten degrees of freedom (DOF) redundant robot manipulator based on three DOF parallel platforms is introduced. The main contents of the paper include configuration, kinematics, mechanical design and control system. The new robot is a hybrid serial system which is composed of a slide pair and three sections of three DOF parallel platforms. The system is driven by hydraulic cylinders and controlled by electric-hydraulic servo valves and STD Bus. It can sweep large workspace and be used for the operations inside of a large container.