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The purpose of this paper is to present a stretched backboneless continuum manipulator, which aims to provide sufficient inner room for potential transportation of objects or fixture of necessary devices, and to reduce the number of motors for reduction of the weight of the system.

A mathematical model of the presented manipulator is established in this paper. To verify the presented theory, the position of the free end was recorded by a high-resolution digital camera in experiment. According to the comparison of experimental values and theoretical values, the error is less than 2.5 per cent. It shows that the mathematical model and theoretical analysis are reasonable; the presented continuum manipulator can reach to desired postures and positions.

This paper presents a new stretched backboneless continuum manipulator supported and driven by cannula tendons. The cannula tendons are composed of rubber tubes and glass fibers. The upper section and the lower section of the presented manipulator are driven by same motors. For steering the manipulator, switched driving strategy is developed based on the presented kinematics model. The presented manipulator possesses six degrees of freedom (DOFs) and has good performance in dealing with complex working environment. The experiment verifies the presented driving strategy.

The presented backboneless continuum manipulator has only two sections and is supported by cannula tendons. Extending this structure to further more sections is a challenge and is left for future research.

The value of this study is to propose a stretched backboneless continuum manipulator, which can provide inner room as large as possible for potential usage and halve the number of motors, for which a switched driving strategy is put forward. As a result, the weight and complexity of the manipulator are decreased. The presented manipulator is able to move in potential complex environments and approach its objects in different postures in virtue of its high flexibility and its six DOFs.

We have reprinted the powerful letter addressed to the Daily Mail by MR. H. W. WILSON, the author of “Ironclads in Action,” advocating the immediate adoption of a policy of reprisals for the Zeppelin murder raids. In our view it is the duty of every journal, whatever may be its raison d'être, to assist in keeping the attention of the public fixed upon this matter, to aid in preventing the general feeling of disgust and indignation from cooling down, and to support those who have the brains to understand the nature of the Hun in their efforts to compel the Government to adopt the most effective means at present available to put an end to the murderous excursions of the German vermin into this country. As MR. WILSON points out, the deliberate Hun policy of slaying women, children and non‐combatants is either permitted by the laws of war recognised by civilised nations or it is not permitted by those laws. If it is permitted, “then clearly the Power which refrains from making similar attacks on the enemy's towns, villages, and residential districts, loses greatly from the military standpoint.” If it is not permitted then the only course— “the force behind the laws of War”—is a policy of drastic reprisals. Moreover, it is the only course that the Hun can understand. The methods of “frightfulness” are definitely laid down in the German military system as methods to be ruthlessly followed whenever this can be done with impunity and the fear of reprisals is also definitely laid down as the only consideration which is to be allowed to operate as a check upn “frightfulness.” “The Power which fails to take reprisals when a great offence is committed is as the negligent judge or the faithless jury that acquits a murderer. It sins against humanity … it encourages the criminal in his crime.”

The very large number of books at present being issued relating to, or connected with the War, conclusively shows to what a great extent the intellectual as well as the material strength of the nation is engrossed by the terrible struggle in which we are engaged. But without abating any of our own interest in the supreme events now taking place, we may well pause to remember that things will not always be thus, and consider carefully before we crowd our shelves with works that are in many cases of very ephemeral value.

The purpose of this paper is to present a novel stretch-retractable single section (SRSS) continuum manipulator which owns three degrees of freedom and higher motion range in three-dimension workspace than regular single continuum manipulator. Moreover, the motion accuracy was analyzed based on the kinematic model. In addition, the experiments were carried out for validation of the theory.

A kinematics model of the SRSS continuum manipulator is presented for analysis on bending, rotating and retracting in its workspace. To discuss the motion accuracy of the SRSS continuum manipulator, the dexterity theory was introduced based on the decomposing of the Jacobian matrix. In addition, the accuracy of motion is estimated based on the inverse kinematics and dexterity theory. To verify the presented theory, the motion of free end was tracked by an electromagnetic positioning system. According to the comparison of experimental value and theoretical analysis, the free end error of SRSS continuum manipulator is less than 6.24 per cent in the region with favorable dexterity.

This paper presents a new stretch-retractable continuum manipulator that the structure was composed of several springs as the backbone. Thus, the SRSS continuum manipulator could own wide motion range depending on its retractable structure. Then, the motion accuracy character of the SRSS continuum manipulator in the different regions of its workspace was obtained both theoretically and experimentally. The results show that the high accuracy region distributes in the vicinity of the outer boundary of the workspace. The motion accuracy gradually decreases with the motion position approaching to the center of its workspace.

The presented SRSS continuum manipulator owns three degrees of freedom. The future work would be focused on the two-section structure which will own six degrees of freedom.

In this study, the SRSS continuum manipulator could be extended to six degrees of freedom continuum robot with two sections that is less one section than regular six degrees of freedom with three single section continuum manipulator.

The value of this study is to propose a SRSS continuum manipulator which owns three degrees of freedom and could stretch and retract to expend workspace, for which the accuracy in different regions of the workspace was analyzed and validated based on the kinematics model and experiments. The results could be feasible to plan the motion space of the SRSS continuum manipulator for keeping in suitable accuracy region.