When computer vision technique is used in robotics, robotic hand–eye calibration is a very important research task. Many algorithms have been proposed for hand–eye calibration. Based on these algorithms, we introduce a new hand–eye calibration algorithm in this paper, which employs the screw motion theory to establish a hand–eye matrix equation by using quaternion and gets a simultaneous result for rotation and translation by solving linear equations. The algorithm proposed in this paper has high accuracy and stable computational efficiency and can be understood easily. Both simulations and real experiments show the superiority of our algorithm over the comparative algorithms.

In this paper, nonlinear dynamic equations of a wheeled mobile robot are described in the state-space form where the parameters are part of the state (angular velocities of the wheels). This representation, known as quasi-linear parameter varying, is useful for control designs based on nonlinear ∞ approaches. Two nonlinear ∞ controllers that guarantee induced 2-norm, between input (disturbances) and output signals, bounded by an attenuation level γ, are used to control a wheeled mobile robot. These controllers are solved via linear matrix inequalities and algebraic Riccati equation. Experimental results are presented, with a comparative study among these robust control strategies and the standard computed torque, plus proportional-derivative, controller.

This paper is concerned with PID control of rigid robots equipped with brushless DC (BLDC) motors when the electric dynamics of these actuators is taken into account. We show that an adaptive PID controller yields global stability and global convergence to the desired link positions. Moreover, we also show that virtually the PID part of the controller suffices to achieve the reported global results. We present a theoretical justification for the torque control strategy, commonly used in practice to control BLDC motors. Our controller does not require the exact knowledge of neither robot nor actuator parameters.

In this paper, a new biomimetic tendon-driven actuation system for prosthetic and wearable robotic hand applications is presented. It is based on the combination of compliant tendon cables and one-way shape memory alloy (SMA) wires that form a set of agonist–antagonist artificial muscle pairs for the required flexion/extension or abduction/adduction of the finger joints. The performance of the proposed actuation system is demonstrated using a 4 degree-of-freedom (three active and one passive) artificial finger testbed, also developed based on a biomimetic design approach. A microcontroller-based pulse-width-modulated proportional-derivation (PWM-PD) feedback controller and a minimum jerk trajectory feedforward controller are implemented and tested in an ad hoc fashion to evaluate the performance of the finger system in emulating natural joint motions. Part II describes the dynamic modeling of the above nonlinear system, and the model-based controller design.

In this paper, we propose a control method to achieve three objectives simultaneously: velocity regulation during free motion, impact damping and finally force reference tracking. During impact, the parameters are switched in order to dissipate the energy of the system as fast as possible and the optimal switching criteria are deduced. The possibility of sliding regimes is analysed and the theoretical results are verified in simulations.

This paper is an investigation of completely mechanical quick changeable joints for multipurpose explosive ordnance disposal (EOD) robots. With the assistance of a quick changeable joint, an ordinary EOD robot becomes a multipurpose robot with an end effector which can be switched during the task. This exchangeable end effector permits the robot to perform more complex duties. Making the joint completely mechanical increases its capacity and decreases its complexity of control and risk of failure. In this paper, the design, manufacturing, and testing stages are explained for four quick changeable joints each possessing different physical working principles. The test results reveal the best design for a multipurpose EOD robot and give ideas for other uses of quick changeable joints. Employing the quick changeable joints in other mobile robot applications can increase a robot's capacity and efficiency.

This paper presents a quadratic programming (QP) form algorithm to realize on-line planning of mobile manipulators with consideration for improving the stability level. With Lie group and screw tools, the general tree topology structure mobile robot dynamics and dynamic stability attributes were analysed. The stable support condition for a mobile robot is constructed not only in a polygonal support region, but also in a polyhedral support region. For a planar supporting region, the tip-over avoiding requirement is formulated as the tip-over prevent constraints with the reciprocal products of the resultant support wrench and the imaginary tip-over twists, which are constructed with the boundaries of the convex support polygon. At velocity level, the optimized resolution algorithm with standard QP form is designed to resolve the inverse redundant kinematics of the Omni-directional Mobile ManipulatorS (OMMS) with stability considerations. Numerical simulation results show that the presented methods successfully improve the stability level of the robot within an on-line planning process.

People detection and tracking are essential capabilities in order to achieve a natural human–robot interaction. A great portion of the research in that area has been focused on monocular techniques. However, the use of stereo vision for these purposes concentrates a great interest nowadays. This paper presents a multi-agent system that implements a basic set of perceptual-motor skills providing mobile robots with primitive interaction capabilities. The skills designed use stereo and ultrasound information to enable mobile robots to (i) detect an interested user who desires to interact with the robot, (ii) keep track of the user while they move in the environment without confusing them with other people, and (iii) follow the user along the environment avoiding obstacles in the way. The system presented has been evaluated in several real-life experiments achieving good results and real-time performance on modest computers.

In this paper, adaptive control of kinematically redundant robot manipulators is considered. An end-effector tracking controller is designed and the manipulator's kinematic redundancy is utilized to integrate a general sub-task controller for self-motion control. The control objectives are achieved by designing a feedback linearizing controller that includes a least-squares estimation algorithm to compensate for the parametric uncertainties. Numerical simulation results are presented to show the validity of the proposed controller.

This paper analyzes the stabilization problem from the energy point of view. Perturbations are detected by the gyros and categorized according to the constraints on the zero-moment point, energy, and walking pattern. Ankle torque is exerted to extend the linear inverted pendulum mode (LIPM). Compensation movement is computed according to the analysis on the energy of LIPM and the influence of disturbance to the energy. The experimental results from both the simulation and the physical robot not only proved effective but also explain various human reactions to disturbance in locomotion.

The paper describes a skiing robot that is capable of skiing autonomously on a ski slope. The robot uses carving skiing technique. Based on a complex sensory system it is capable of autonomously navigating on the ski slope, avoiding obstacles, and maintaining a stable position during skiing on an unknown ski slope. The robot was tested using simulation in a virtual reality environment as well as on a ski slope.

In this paper obtaining the optimal configuration of the dual-arm cam-lock (DACL) robot at a specific point is addressed. The objective is to optimize the applicable task-space force in a desired direction. The DACL robot is a reconfigurable manipulator formed by two parallel cooperative arms. The arms normally operate redundantly but when needed, they can lock into each other in certain joints in order to achieve a higher stiffness, while losing some degrees of freedom. Furthermore, the dynamics of the DACL robot is discussed and parametrically formulated. Considering the geometrical constraints at a given point in the robot's workspace, the optimum configuration for maximizing the cooperatively applicable force by dual arms is determined.

This paper presents an automatic training method based on the Baum–Welch algorithm (also known as EM algorithm) and a robust low-level controller. The method has been applied to the indoor autonomous navigation of a surveillance robot that utilizes a WiFi+Ultrasound Partially Observable Markov Decision Process (POMDP). This method uses a robust local navigation system to automatically provide some WiFi+Ultrasound maps. These maps could be employed within probabilistic global robot localization systems. These systems use a priori probabilistic map in order to estimate the global robot position. The method has been tested in a real environment using two commercial Pioneer 2AT robotic platforms in the premises of the Department of Electronics at the University of Alcalá. Some experimental results and conclusions are presented.

This study concerns the design and prototype of four different mobile robot platforms for rescue robot operations after an earthquake. At first, a test field is constructed to represent a mildly damaged earthquake zone. The test field consists of eight different sections: sand, gravel, ditch, water, bridge, incline, decline, and turn. The mechanical structure, electronics, software, communication, and possible sensory systems are explained. After the robots are manufactured, they are physically tested for their performance in the test field for 18 different parameters. The test results show the effective body structure. Challenges of the rescue robot design are explained and future expectations are given.

This paper presents two fully parallel manipulators of type 5-5 and 4-5 with special geometry that makes them partially decoupled. The direct kinematic analysis and the singularity study of these manipulators are addressed, which show that the motion of the manipulators can be easily controlled. Computational considerations are reported, which demonstrate that the algorithms proposed for the direct kinematic analysis are very efficient. Moreover, a comparison with other special geometries illustrates that the proposed manipulators are valuable solutions and represent a good compromise between an efficient controllability and a simple practical feasibility.

This paper describes the development of a desktop robotic system that enables the plug-and-play function through the USB (universal serial bus) port of a personal computer (PC). Thus a new kind of desktop PC peripheral is invented that has programmable manipulability. The robotic system is realized on an internally distributed control structure that facilitates higher system reliability. A PID control algorithm is implemented on a prototype of the proposed system, to demonstrate the system's ability to implement feedback control. Experimental results show the performance and properties of the proposed system.

The workspace of a parallel manipulator is usually smaller than the size of the robot itself. It is important to derive new structures that enjoy the advantages of parallel manipulators and also have a large workspace. In this paper we present two configurations of similar structures RRRS and RRSR with rotating links. The RRRS structure has a relatively large workspace—larger than the size of the robot itself—which is not common in parallel robots. The inverse and forward kinematics of the robots are presented. The workspaces of the robots are compared to similar and well-known structures, such as Eclipse, Alizade, Delta, and Hexa robots.

Restoration of mechanical energy dissipating on impact at the ground is necessary for sustainable gait generation. Parametric excitation is one approach to restore the mechanical energy. Asano et al. (“Parametric excitation mechanisms for dynamic bipedal walking,” IEEE International Conference on Robotics and Automation (2005) pp. 611–617.) applied parametric excitation to a biped robot with telescopic-legs, in which up-and-down motion restores total mechanical energy like playing on the swing. In this paper, parametric excitation principle is applied to a kneed biped robot with only knee actuation and it is shown that the robot walks successively without hip actuation. We also examine influences of several parameters and reference trajectory on walking performance.

A novel 3SPS+SP parallel manipulator (PM) with 4-dof is proposed. Its kinematics and statics are analyzed systematically. The analytic formulae for solving the displacement, velocity, acceleration, workspace, active forces and constrained force are derived. The analytic results are verified by using a simulation mechanism of the 3SPS+SP PM.

The paper presents a method of reaction force and moment calculation for a 3-RSS pure translational parallel link robot (Delta-type parallel robot), in which the inverse and forward kinematics of the parallel link robot are directly analyzed according to kinematic structure of the parallel robot. For dynamic analysis, the parallel robot is imaginarily parted into three serial ones, and their actual joint torques are determined by the virtual work principle. To obtain the reaction force and moment of the parallel robot acting on the base, which is the composition of the reaction forces and moments of the three serial robots, the Newton–Euler Method is adopted. To show the validity of the presented method, the simulation analysis and experimental results are given, the experimental results tally with the calculation value.