The evaluation of joint velocity, torque, and power capability of the 8-PSS redundant parallel manipulator is investigated in this paper. A series of new joint capability indices with obvious physical meanings are presented. The torque index used to evaluate the respective joint dynamic capability of the redundant parallel manipulator is decoupled into the acceleration, velocity, and gravity term. With these velocity, torque, and power indices, it is possible to control the respective joint capability of the redundant parallel manipulator in different directions. The indices have been applied to evaluate the joint capability of the redundant parallel manipulator by simulation. They are general and can be used for other types of parallel manipulators.

We present a miniature magnetic climbing robot with dimensions 96 × 46 × 64 mm3. With two degrees of freedom it is able to climb ferromagnetic surfaces and to make inner plane to plane transitions whatever their inclination is. This robot, named TRIPILLAR, combines triangular-shaped magnetic caterpillars and frame magnets. This particular configuration allows, for example, to move from ground to wall and ceiling and back. This achievement opens new avenues to use mobile robotics for industrial inspection with stringent size restrictions, such as the ones encountered in power plants.

Relatively large errors can exist in industrial robots as a result of mismatch between the controller model and the corresponding physical model. The paper outlines a novel approach for accuracy assessment and adjustment of multiaxis industrial robots through a low-cost ball-bar link system. The features of the ball-bar, which incorporated a 12 mm range digital displacement transducer in conjunction with a PC, are discussed. The ball-bar device was used in both a trammelling and circular mode of operation. This produced data which not only related to the accuracy of the robot but also enabled joint errors to be significantly reduced.

Finding singular configurations (singularities) has an important role during the design, trajectory planning, and control stages of mechanisms because in these configurations, the instantaneous kinematics is locally undetermined. In this paper, a systematic method is presented to obtain singular configurations of spherical mechanisms with input and output links. The method extends the use of instantaneous poles to singularity analysis of spherical mechanisms and offers geometric conditions for any type of singularities occurring in these mechanisms.

The use of active control techniques has intensified in various control applications, particularly in the field of aircraft systems. This paper presents an investigation into the control of rigid-body and flexible motion of a twin rotor multi-input multi-output system (TRMS) using intelligent inverse-model-based control schemes. The TRMS is an aerodynamic test rig representing the control challenges of modern air vehicle. The augmented feedback PID and feedforward inverse-model-based control has led to good tracking response and vibration reduction of the TRMS, with the use of particle swarm optimisation (PSO). As a comparison, methods using PID controllers are also presented. Experimental results are obtained using the test rig, confirming the viability and effectiveness of the proposed methodology as opposed to conventional PID controllers. The results and evidence from this method are justified, presented and discussed.

This paper presents a novel trajectory planning method for a flexible Cartesian robot manipulator in a point-to-point motion. In order to obtain an exact mathematical model, the parameters of the equation of motion are determined from an identification experiment. An artificial neural network is employed to generate the desired base position, and then, a particle swarm optimization technique is used as the learning algorithm, in which the sum of the displacements of the manipulator is chosen as the objective function. We show that the residual vibrations of the manipulator can be suppressed by minimizing the displacement of the manipulator. The effectiveness and validity of the proposed method are demonstrated by comparing the simulation and experimental results.

In this paper, a generalized form of the antipodal method from multi-finger grasping is presented and implemented for investigating the workspace of a wide range of planar wire-actuated parallel manipulators. Manipulators with distinct wire attachment points on the base and mobile platform are considered, in the absence and presence of external force. The examined workspaces are verified with the corresponding workspaces developed using static force analysis. By applying an external force, modeled as a wire for the antipodal method, the characteristics of the manipulator could be altered by enlarging its workspace in the direction of the applied force.

Cyclic coordinate descent (CCD) inverse kinematics methods are traditionally derived only for manipulators with revolute and prismatic joints. We propose a new numerical CCD method for any differentiable type of joint and demonstrate its use for serial-chain manipulators with coupled joints. At the same time more general and simpler to derive, the method performs as well in experiments as the existing analytical CCD methods and is more robust with respect to parameter settings. Moreover, the numerical method can be applied to a wider range of cost functions.

The design, control, and actuation of legged robots that walk is well established, but there remain unsolved problems for legged robots that run. In this work, dynamic principles are used to develop a set of heuristics for controlling bipedal running and acceleration. These heuristics are then converted into control laws for two very different bipedal systems: one with a high-inertia torso and prismatic knees and one with a low-inertia torso, articulated knees, and mechanical coupling between the knee and ankle joints. These control laws are implemented in simulation to achieve stable steady-state running, accelerating, and decelerating. Stable steady-state running is also achieved in a planar experimental system with a semiconstrained torso.

In this paper, we propose a unique, decoupled 3 degree-of-freedom (DOF) parallel wrist. The condition required for synthesizing a fully isotropic parallel mechanism is obtained on the basis of the physical meaning of the row vector in the Jacobian matrix. Specifically, an over-constrained spherical 3-DOF parallel mechanism is presented and the modified structure, which avoids the redundant constraints, is also introduced. The proposed manipulator is capable of decoupled rotational motions around the x, y, and z axes and contains an output angle that is equal to the input angle. As this device is analyzed with the Jacobian matrix, the mechanism is free of singularity within its workspace and maintains homogenous stiffness over the entire workspace.

In this paper, an offline algorithm generates gaits for robotic biped running motion. A minimization procedure on a novel objective function produces initial joint velocities for the flight phase given the initial joint angles. These computed initial velocities ensure a reasonable starting point for the constrained dynamic optimization procedure to try and formulate a gait that minimizes energy consumption. The simulated robot runs even on ground and up stairs. Results demonstrate the rigid robot solution has a intuitively satisfying human-like motion with an energy consumption that appears reasonable for a rigid robot.

D. Zhang and F. Zhang addressed the issue of designing and analyzing totally decoupled 3-DOF spherical parallel manipulators (SPMs) and concluded that the SPMs in Figs. 5(a) and 5(b) of ref. [1] are completely decoupled and fully isotropic (see Abstract, Section 5, and Conclusions in ref. [1]). This topic is of great interest to researchers working in the general area of parallel mechanisms. However, we disagree with the authors of ref. [1] on their conclusion.