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The adaptation of eight ‘Centaurus’ engines, grouped in pairs, to drive airscrews presenting only four disks to the air stream in the Bristol ‘Brabazon’ is described, including their submersion within the wing thickness, and special cooling arrangements. The reasons chosen for the lay‐out of the power plant are given. Description of the design of the dual‐reduction gear includes the primary and auxiliary drives, freewheels, and propeller shafts. The operating system of the propellers is briefly reviewed. The plant used and programme for testing, including fire precautions and detection and an actual engine fire test, are described.

Reconfigurability of the assembly fixtures, which enables a set of sheet metal automotive parts to be produced on a single production line, is becoming crucial to maintaining competitiveness in the rapidly changing market. One of the key issues in reconfigurable fixture design is to identify the fixture configuration and make sure there is enough workspace for a family of parts. The purpose of this paper is to address this issue, through the design and analysis of two novel reconfigurable fixturing robots.

Following an introduction, the application of the reconfigurable fixturing robot addressed in this paper is described; it is characterized by using parallel manipulator as programmable fixture elements. Kinematic design and reconfigurable design of the fixturing robot is presented based on screw theory and modularized design, respectively.

The proposed reconfigurable fixturing robots can transform their configurations with 4 DoF (degrees‐of‐freedom), and have a continuous workspace for their application.

Reconfigurability of the assembly fixtures is an important issue for automotive manufacturing, due to the highly competitive nature of this industry. The proposed reconfigurable fixturing robots can greatly facilitate the development of new models of vehicles.

Manipulator motion accuracy is a fundamental requirement for precision manufacturing equipment. Light weight manipulators in high speed motions are vulnerable to deformations. The purpose of this work is to analyze the effect of link deformation on the motion precision of parallel manipulators.

The flexible dynamics model of the links is first established by applying the Euler–Bernoulli beam theory and the assumed modal method. The rigid-flexible coupling equations of the parallel mechanism are further derived by using the Lagrange multiplier approach. The elastic energy resulting from spiral motion and link deformations are computed and analyzed. Motion errors of the 3-link torque-prismatic-torque parallel manipulator are then evaluated based on its inverse kinematics. The validation experiments are also conducted to verify the numerical results.

The lateral deformation and axial deformation are largest at the middle of the driven links. The axial deformation at the middle of the driven link is approximately one-tenth of the transversal deformation. However, the elastic potential energy of the transversal deformation is much smaller than the elastic force generated from axial deformation.

Knowledge on the relationship between link deformation and motion precision is useful in the design of parallel manipulators for high performing dynamic responses.

This work establishes the relationship between motion precision and the amount of link deformation in parallel manipulators.

The purpose of this paper is to build a seven‐degrees of freedom (DOF) parallel‐serial robot system which has the advantage of mechanical novelty and simplicity compared with the existing platforms, and to share the experience of converting a popular motion base to an industrial robot for use in full‐mission tank training processes of three armored arms.

By studying the concept of the robot system, a novel parallel‐serial robot with seven DOF driven by electrical servo motors is built. And the transmission modules and Hooke joints are explored and designed in detail. Then the inverse kinematics based on coupling compensation and time‐jerk synthetic optimization methods for trajectory planning of the simulator are presented and further discussed in order to satisfy the requirements of high stability and perfect performance. In advance, the feasibility and applicability of this triune parallel‐serial robot system are verified.

A prototyped test shows that the performance of the system is of a satisfaction with real‐time tracking any trajectories given by the visual system smoothly. Finally, the characteristics of the robot system are realized and verified by experiments and an industrial application.

The triune full‐mission tank training simulator developed in this paper has been used in the military industry and it has a great potential application.

This successful usage of the novel and simple parallel robot system in the military industry expands the range of its applications in real‐life task more operators training. And the proposal methods of inverse kinematics based on coupling compensation and trajectory planning enhanced the theoretical research of the parallel robot.

WITHIN the last year or so we have learned to glue metals together with a strength which brings this method of joining materials into competition with riveting, at least in the thin gauges used in the aircraft and motor industries. Apart from this new extension of gluing to the metal working trades synthetic adhesives have already revolutionized the woodworking industries. This revolution is due to the superior quality of the resulting products and the increased rate of output made possible by the intrinsic high speed of setting of synthetic adhesives aided by such novel methods as high frequency heating, infra‐red heating and the like. In aircraft in particular the “weather‐resistance” of synthetic adhesives has largely removed the disadvantages of wood construction, due to the use of casein glues, so much in evidence in the first winter of this war. It may be said therefore that gluing has been raised from the status of a useful but humble convenience of daily life to a process of engineering significance. But before engineers can use gluing in the fabrication of structures they must be provided with data sufficient to enable thorn to compute the strength of the joints, and we at Aero Research Ltd. have therefore endeavoured to find a simple relation between the strength of a lap joint and its geometry. Such a simple relation is found in “the joint factor” which is defined3 as the square root of the thickness of the sheet divided by the length of the overlap.

Thruster point assembly mechanism (TPAM) of the electric propulsion system allows to adjust the thrust vector, so that the thrust vector is directed to the satellite center of gravity (COG) during the satellite on-orbit working period. In this way the impact of disturbance torque caused by deviation of the thrust vector from the satellite COG during thruster ignition can be decreased. Therefore, the control accuracy of satellite is influenced directly by the control accuracy of TPAM. On the other hand, the on-orbit application of TPAM is restricted to the on-orbit computer resource. Therefore, the purpose of this paper is to design a control strategy for TPAM, and the strategy should not only be able to control the TPAM precisely but also be easily implemented by the on-board computer.

First, the structure and work principle of TPAM are discussed, and the mathematical model based on D-H coordinate system is built for it. Then the fitting methods are utilized to design the control strategy of TPAM. Absolute position fitting-based control strategy and relative position fitting-based control strategy are designed, and the least squares algorithm is introduced for parameter selection.

Simulations and tests are provided for the TPAM. Compared with the state-of-the-art PD controller, the proposed control strategy shows smaller overshoot and more simple realization. The experiment results are matched with the simulation results and both the experiment and simulation results show the validity of the proposed control strategies.

The designed control strategies can be used for the TPAM of some satellite’s electric propulsion system.

The mathematical model of the TPAM based on D-H coordinate system is given. The absolute position fitting-based control strategy and relative position fitting-based control strategy are proposed. Compared with existing methods, the two control strategies have more simple structure and smaller amount of computations. Furthermore, the relative position fitting-based control strategy achieves high precision with simple structure.

The purpose of this paper is to propose a two-degrees-of-freedom wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism based on spring, in order to improve the robot’s athletic ability, load capacity and rigidity, and to ensure the coordination of multi-modal motion.

First, based on the rotation transformation matrix and closed-loop constraint equation of the parallel trunk joint mechanism, the mathematical model of its inverse position solution is constructed. Then, the Jacobian matrix of velocity and acceleration is derived by time derivative method. On this basis, the stiffness matrix of the parallel trunk joint mechanism is derived on the basis of the principle of virtual work and combined with the deformation effect of the rope driving pair and the spring elastic restraint pair. Then, the eigenvalue distribution of the stiffness matrix and the global stiffness performance index are used as the stiffness evaluation index of the mechanism. In addition, the performance index of athletic dexterity is analyzed. Finally, the distribution map of kinematic dexterity and stiffness is drawn in the workspace by numerical simulation, and the influence of the introduced spring on the stiffness distribution of the parallel trunk joint mechanism is compared and analyzed. It is concluded that the stiffness in the specific direction of the parallel trunk joint mechanism can be improved, and the stiffness distribution can be improved by adjusting the spring elastic structure parameters of the rope-driven branch chain.

Studies have shown that the wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism based on spring has a great kinematic dexterity, load-carrying capacity and stiffness performance.

The soft-mixed structure is not mature, and there are few new materials for the soft-mixed mixture; the rope and the rigid structure are driven together with a large amount of friction and hindrance factors, etc.

It ensures that the multi-motion mode hexapod mobile robot can meet the requirement of sufficient different stiffness for different motion postures through the parallel trunk joint mechanism, and it ensures that the multi-motion mode hexapod mobile robot in multi-motion mode can meet the performance requirement of global stiffness change at different pose points of different motion postures through the parallel trunk joint mechanism.

The trunk structure is a very critical mechanism for animals. Animals in the movement to achieve smooth climbing, overturning and other different postures, such as centipede, starfish, giant salamander and other multi-legged animals, not only rely on the unique leg mechanism, but also must have a unique trunk joint mechanism. Based on the cooperation of these two mechanisms, the animal can achieve a stable, flexible and flexible variety of motion characteristics. Therefore, the trunk joint mechanism has an important significance for the coordinated movement of the whole body of the multi-sport mode mobile robot (Huang Hu-lin, 2016).

In this paper, based on the idea of combining rigid parallel mechanism with wire-driven mechanism, a trunk mechanism is designed, which is composed of four spring-based wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism in series. Its spring-based wire-driven 4SPS/U rigid‒flexible parallel trunk joint mechanism can make the multi-motion mode mobile robot have better load capacity, mobility and stiffness performance (Qi-zhi et al., 2018; Cong-hao et al., 2018), thus improving the environmental adaptability and reliability of the multi-motion mode mobile robot.

This paper aims to verify the workspace and movement performance of a redundantly actuated humanoid chewing robot.

A redundantly actuated humanoid chewing robot with 6-PUS linkages and two higher kinematic pairs (HKPs) is introduced. The design of HKPs is specified by mimicking the temporomandibular joint (TMJ) structure obtained through a computed tomography scan of the mastication system. The border movement, mouth-opening trajectory and velocity of subjects’ lower incisor point are measured by using the mandibular kinesiograph. Based on the kinematics, the envelope of the workspace is analyzed. The workspace and mouth-opening movement experiments are carried out. The border movement of the lower incisor point is measured. The mouth-opening trajectory is planned and tested on the chewing robot.

Comparing with measurement results of border movement and mouth-opening movement of human, it is shown that the humanoid chewing robot can meet the workspace requirements and is able to perform mouth-opening movement like human-beings.

The chewing robot is designed to reproduce human jaw movements and application in test of dental components and materials or evaluation of food textural properties.

The chewing robot is inspired by the mastication system which itself is mechanically redundant because of the TMJ and more muscles than required. The novel spatial redundantly actuated chewing robot is the first of this kind with two HKPs to mimic the human TMJ and is a higher fidelity mechanism.

Several finite element models were proposed to investigate the effects of voids and their interactions on SMT solder joint reliability in thermal mismatch loading. Both linear elastic analysis and non‐linear and time‐dependent finite element analysis were performed on models with different sizes and locations of voids in solder joints. The focus was on the interactions of the two voids. Various distances between voids are considered. Constitutive equations accounting for both plasticity and creep for one solder material were assumed and implemented in a finite element program. The following observations have been obtained: (i) the stress and strain in a solder joint of two voids are different from those of a one void joint; (ii) the stress and strain reach a maximum for a particular void size and location either along the interface of the solder joint or at the edges of voids; (iii) the initiation of interfacial debonding may be induced by the interaction of the voids; (iv) creep due to thermal cycling has a significant effect on solder joint reliability.