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A tendon-driven snake-arm robot can achieve a bending motion with multiple degrees of freedom (DOF) with a compact structure, which enables the robot to be widely used in confined environments. However, if a conventional tendon-driven snake-arm robot is subject to a lateral force on the distal end, it will experience passive compliance. In this paper, a 2-DOF rolling joint is proposed, based on the opposite-pole attraction of spherical magnets, which has a relatively simple structure compared with traditional joints. By serially connecting the 2-DOF rolling joints, a novel snake-arm robot is designed utilizing a tendon-driven approach. The kinematic model and workspace of the snake-arm robot are obtained, and the bending motion is validated. Based on the kinematic model, it is theoretically proven that the proposed robot can avoid passive compliance. In addition, this feature is verified through load experiments on the developed prototype.

A gear is used not only for power transmission but also in precision positioning. A conventional and general gear has only one degree of freedom motion. Therefore, the case of its use is limited. In this paper, we propose and manufacture an innovative spherical gear. The proposed spherical gear has a multiple degrees of freedom motion. Compared with other spherical gear, the proposed spherical gear does not have complex shape. Moreover, the handle of the proposed spherical gear is similar to that of a spur gear. The experimental apparatus using the spherical gear pair measures a transmission efficiency and an angular backlash between the gears. According to experimental results, the spherical gear teeth could mesh firmly and transmit power at any shaft angle. In addition, the maximum transmission efficiency and the angular backlash become about 87.1% and 16.9 mrad when the shaft angle is 0°, respectively.

Studies have developed various types of soft robotic gloves for hand rehabilitation in recent years. Most soft actuators achieved a sufficient thumb flexion assist while lacking opposition support, which requires the coordination of thumb flexion and abduction-adduction. The difficulties for thumb support lie in the intrinsic complexity of thumb movements and spatial restriction of the hand. To realize multiple degrees of freedom of the thumb and make effective use of the limited space of the hand's dorsal side, we optimized and compared two approaches for thumb support. The combination approach used two independent soft actuators for thumb flexion and abduction-adduction support, respectively. The all-in-one approach used one single soft actuator to assist motions in different directions. We designed the soft actuators for each approach based on the thumb's biomechanical characteristics and evaluated their thumb flexion, abduction support performance in terms of the range of motion (RoM) and force output, and the opposition support performance using an enhanced Kapandji test. The results showed a larger abduction RoM and force output of the composition approach and a higher Kapandji score of the all-in-one approach, indicating that the two approaches might be applicable for thumb support but have the advantage in different rehabilitation stages.

A model that captures the weak frequency sensitivity of elastic hysteretic damping is proposed for the time-domain simulation of structures with multiple degrees of freedom (MDOF) under free or forced vibration. The model is based on a recently proposed modification to the conventional single degree of freedom (SDOF) viscous damping model, utilising a correction factor computed based on the local instantaneous response to adjust the damping coefficient such that the dissipated energy remains insensitive to the frequency characteristics of the motion. The model compares favourably to the well-established viscous (incl. Collar’s frequency correction), Rayleigh and Reid MDOF models, is applicable to any type of loading and, unlike other classes of damping models, such as Rayleigh, modal, Bouc-Wen, Biot, and Collar/Neumark, does not require extensive calibration, knowledge of the past history of motion, or a priori knowledge of the excitation characteristics and frequency.

Currently, additive manufacturing (AM) technology has received significant attention from both academia and industry. AM is characterized by fabricating geometrically complex components in a layer-by-layer manner, and greatly reduces the geometric complexity restrictions compared with traditional manufacturing. As AM is no longer limited to the normal three degrees of freedom (DOF) (three-axis) systems, there are many new multi-DOF AM machines been developed with various aims. It is, therefore, necessary that a review of the topic with regard to multi-DOF AM is performed for future AM system development. This paper, focuses on reviewing publications related to multi-DOF AM according to the number of DOF on an AM machine. The major part of the paper aims to inspire both researchers and engineers to further develop and improve multi-DOF AM systems to achieve different goals. The final part of the paper discusses the findings together with future research directions.

It is well-known that the responses of a structure are different when subjected to a static load or a sudden step load. The dynamic amplification factor (DAF), which is defined as the ratio of the amplitude of the vibratory response to the static response, is normally used to depict the dynamic effect. For a single-degree-of-freedom system (SDOF) subjected to a sudden dynamic load, the maximum value of DAF is 2. Many design guidelines therefore use 2 as an upper bound to consider the dynamic effect. For a civil engineering structure, which is normally a multiple-degrees-of-freedom (MDOF) system, the DAF may exceed 2 in certain circumstances. The adoption of 2 as the upper bond as suggested by the design guidelines therefore may lead to unsafe structural design. Very limited studies systematically investigate the DAF of a MDOF system. This study theoretically investigates the DAF of a MDOF system when it is subjected to a step load based on the fundamental theory of structural dynamics. The condition on which the DAF may exceed 2 is defined. Two numerical examples and one experimental study of a cable-stayed bridge subjected to sudden cable loss are presented to illustrate the problem.

A multiple-degree-of-freedom (multi-DOF) motor can constitute small-sized and lightweight systems capable of performing complicated motions. Furthermore, the prospects for applications to industrial instruments via a direct drive are promising. This study aimed to develop practical multi-DOF motors capable of performing high-power rotary and linear motions using conventional three-phase inverters. A motor that performs rotary and linear motions is proposed. First, a method is presented for installing a salient pole on a needle with magnets. The method facilitates the use of soft magnetic materials with low eddy-current loss as iron cores. This study demonstrated the effectiveness of the salient pole for increasing the electromagnetic force. The model is used to explain the interactive magnetic interference generated by the armature currents for rotational and translation motions.

This paper introduces the modular design and manufacturing method, mechanical model, and test verification of a new type of soft actuator driven by fluid. First, the modular design scheme and driving principle of omnidirectional bending and elongation of the soft actuator are described. Three print-based elastic air cavities constrained by fire lines are distributed radially inside the actuator. The actuator can complete the 3 DOF motions of omnidirectional bending and elongation. From the basic principle of material mechanics, a novel mechanical model of the soft elastomer actuator is established. By numerically solving the nonlinear model, the relationship between actuator elongation/bending angle and driving pressure is obtained. The theoretical prediction and test results show that the deformation of the actuator exhibits a linear relationship with pressure when the chambers are charged. Additionally, the maximum allowable load force on the actuator terminal also exhibits good linearity when the driving pressure increases. Furthermore, the established mechanical model, which considers gravity effects can more accurately describe the features of bend and elongation of the actuator. The results shows that the proposed model is more convenient than the FEM models. This study provides theoretical support for accurate control of a soft actuator.

Earthquake response mitigation of base-isolated (BI) buildings with a tuned mass damper (TMD) is investigated. Two-dimensional reinforced concrete buildings having multiple degrees of freedom are n...

This paper presents the design, fabrication, and testing of a novel three-dimensional (3D) three-fingered electrothermal microgripper with multiple degrees of freedom (multi DOFs). Each finger of the microgripper is composed of a V-shaped electrothermal actuator providing one DOF, and a 3D U-shaped electrothermal actuator offering two DOFs in the plane perpendicular to the movement of the V-shaped actuator. As a result, each finger possesses 3D mobilities with three DOFs. Each beam of the actuators is heated externally with the polyimide film. The durability of the polyimide film is tested under different voltages. The static and dynamic properties of the finger are also tested. Experiments show that not only can the microgripper pick and place microobjects, such as micro balls and even highly deformable zebrafish embryos, but can also rotate them in 3D space.

Developing robotic manipulators capable of performing effective physical interaction tasks is a challenging topic. In this study, we design a soft robotic arm (SRA) with multiple degrees of freedom inspired by the flexible structures and the unique motion mechanism of the octopus arm. The SRA is fabricated with elastomeric materials, which consists of four series of integrated pneumatic chambers that play similar roles as the muscles in the octopus arm can achieve large bending in various directions with variable stiffness. This SRA displays specified movements via controlling pressure and selecting channels. Moreover, utilizing parallel control, the SRA demonstrates complicated three-dimensional motions. The force response and motion of the SRA are determined both experimentally and computationally. The applications of the present SRA include tightly coiling around the objects because of its large bending deformation (nearly $$360^{{\circ }})$$ , grasping multiple objects, and adjusting the grabbing mode in accordance with the shape of objects.

A multivariable approach of modeling and feedforward control of rate-independent hysteresis in multi-dof piezoelectric actuators is proposed in this paper. For that, the classical Prandtl–Ishlinskii (CPI) hysteresis model is extended into multivariable. Then, based on the inverse multiplicative structure and on the multivariable CPI model, a compensator is suggested. The proposed compensator does not require an extra-calculation: As soon as the model is identified, the compensator is obtained by structure. Furthermore, inversion of the model is avoided. Additionally to the hysteresis suppression, the multivariable compensator permits to reduce the cross-couplings between the axes which is not possible with standard techniques. The modeling and the inversion-free compensator are afterward applied to a two-degrees-of-freedom (2-dof) piezoactuator. The extensive investigated experimental tests demonstrate that the strong cross-couplings and the strong hysteresis in the two axes can be substantially reduced and linearized, respectively.

To reduce the torsional vibration of vehicle power transmission system (VPTS), a torsional vibration model with multiple degrees of freedom (MDOF) of VPTS was established. The scheme of equipping torsional vibration dampers (TVDs) on the drive shaft was employed by the calculation of the forced vibration and the free vibration of the VPTS. The energy method was used to optimize the parameters of single-stage, two-stage parallel, and two-stage series TVDs based on the principle that balances the damping effect and lightweight design. On the basis of this, the parameters of the models incorporating TVD and elastic couplings (ECs) were optimized. Results showed that the proposed method can ensure the damping effects of TVD and realize the lightweight.

End-effector tools with low weight, multiple degrees of freedom have significant application significance. At present, motor-driven robot operating tools generally have more complicated transmission systems as well as actuators, and the weight is also heavy. In this paper, a bolt-screwing tool based on a pneumatic slip ring structure is designed, which can realize two-DOF motion of clamping-releasing and rotating. The tool consists of a pneumatic slip ring with sealed structure and a cylinder driven gripper. This article also introduces the control strategy required to screw the bolt, and describes the configuration of the experiment. Finally, the bolt is screwed into the thread hole in the experiment to verify the reliability of the screw assembly tool and the effectiveness of the corresponding control scheme.

In this paper, a morphing carbon fibre composite aerofoil concept with an active trailing edge is proposed. This aerofoil features of camber morphing with multiple degrees of freedom. The shape morphing is enabled by an innovative structure driven by an electrical actuation system that uses linear ultrasonic motors (LUSM) with compliant runners, enabling full control of multiple degrees of freedom. The compliant runners also serve as structural components that carry the aerodynamic load and maintain a smooth skin curvature. The morphing structure with compliant truss is shown to exhibit a satisfactory flexibility and loading capacity in both numerical simulations and static loading tests. This design is capable of providing a pitching moment control independent of lift and higher L/D ratios within a wider angle-of-attack range. Such multiple morphing configurations could expand the flight envelope of future unmanned aerial vehicles. A small prototype is built to illustrate the concept, but as no off-the-shelf LUSMs can be integrated into this benchtop model, two servos are employed as actuators, providing two controlled degrees of freedom. This paper received a Written Paper Prize - Bronze Award from the Royal Aeronautical Society in 2018.

Untethered, controllable, mobile microrobots have been proposed for numerous applications, ranging from micro-manipulation, in vitro tasks (e.g., operation of microscale biological substances) to in vivo applications (e.g., targeted drug delivery; brachytherapy; hyperthermia, etc.), due to their small-scale dimensions and accessibility to tiny and complex environments. Researchers have used different magnetic actuation systems allowing custom-designed workspace and multiple degrees of freedom (DoF) to actuate microrobots with various motion control methods from open-loop pre-programmed control to closed-loop path-following control. This article provides an overview of the magnetic actuation systems and the magnetic actuation-based control methods for microrobots. An overall benchmark on the magnetic actuation system and control method is also discussed according to the applications of microrobots.

The study of the mechanical ruling process of aluminum grating needs a new test device. And a program controlled test device for mechanical ruling was analyzed, designed, manufactured and tested in this paper. The developed mechanical ruling techniques of this device to fabricate micropatterns are introduced with the characteristics of multiple degrees of freedom, openness, visualization, and operability. After some primary tests, assessment of microgrooves was performed with mini video microscopy, which confirmed the validity of the new device for mechanical ruling process investigation.

The vibration and noise caused by pressure pulsation, referred to as fluid-borne vibration or fluid-borne noise, are some of the most detrimental problems in hydraulic systems. A Helmholtz silencer with multiple degrees of freedom was proposed to attenuate several harmonic frequencies generated in the hydraulic systems. The silencer consists of a cylindrical vessel with several chokes inside the vessel. The final goal of this research project is the development of a multiple-degree-of-freedom type of Helmholtz silencer that can be applied to hydraulic pump systems operated at different speeds. The aim of this report is to establish the design criteria of the silencer specifications. In particular, the effects of the diameter and length of the choke and the cylindrical volume on attenuation performance were analytically and experimentally investigated.

Piezoelectric actuators play huge role in positioning field and take micro technology to the new level. Micro positioning stages using piezoelectric actuators make it possible to enhance micro-technology. They are the key devices in micro management. This paper presents design and simulation of PZT XY-microstage with multiple degrees of freedom. This XY-Microstage has a high precision positioning. The whole structure is arranged in a symmetrical manner made up of silicon having dimension 20mm×20mm×0.4mm. All PZT actuators can be driven individually, results deflection of a micro stage in different directions. Two actuation units with Moonie amplification mechanism are integrated into the structure. Each actuation unit has the command or control on whole structure for movement in the desired direction. The performances of the XY-Microstage are simulated with the help of Finite Element Method of COMSOL Multiphysics.

This article presents a simple procedure for predicting time-domain vibrational behaviors of a multiple degrees of freedom mechanical system with dry friction. The system equations of motion are discretized by means of the implicit Bozzak–Newmark integration scheme. At each time step, the discontinuous frictional force problem involving both the equality and inequality constraints is successfully reduced to a quadratic mathematical problem or the linear complementary problem with the introduction of non-negative and complementary variable pairs (supremum velocities and slack forces). The so-obtained complementary equations in the complementary pairs can be solved efficiently using the Lemke algorithm. Results for several single degree of freedom and multiple degrees of freedom problems with one-dimensional frictional constraints and the classical Coulomb frictional model are obtained using the proposed procedure and compared with those obtained using other approaches. The proposed procedure is found to be accurate, efficient, and robust in solving non-smooth vibration problems of multiple degrees of freedom systems with dry friction. The proposed procedure can also be applied to systems with two-dimensional frictional constraints and more sophisticated frictional models.

In the present study, the Volterra series theory is adopted to theoretically investigate the force transmissibility of multiple degrees of freedom (MDOF) structures, in which an isolator with nonlinear anti-symmetric viscous damping is assembled. The results reveal that the anti-symmetric nonlinear viscous damping can significantly reduce the force transmissibility over all resonance regions for MDOF structures with little effect on the transmissibility over non-resonant and isolation regions. The results indicate that the vibration isolators with an anti-symmetric damping characteristic have great potential to solve the dilemma occurring in the design of linear viscously damped vibration isolators where an increase of the damping level reduces the force transmissibility over resonant frequencies but increases the transmissibility over non-resonant frequency regions. This work is an extension of a previous study in which MDOF structures installed on the mount through an isolator with cubic nonlinear damping are considered. The theoretical analysis results are also verified by simulation studies.

Soft robots are an interesting alternative for classic rigid robots in applications requiring interaction with organisms or delicate objects. Elastic inflatable actuators are one of the preferred actuation mechanisms for soft robots since they are intrinsically safe and soft. However, these pneumatic actuators each require a dedicated pressure supply and valve to drive and control their actuation sequence. Because of the relatively large size of pressure supplies and valves compared to electrical leads and electronic controllers, tethering pneumatic soft robots with multiple degrees of freedom is bulky and unpractical. Here, a new approach is described to embed hardware intelligence in soft robots where multiple actuators are attached to the same pressure supply, and their actuation sequence is programmed by the interaction between nonlinear actuators and passive flow restrictions. How to model this hardware sequencing is discussed, and it is demonstrated on an 8-degree-of-freedom walking robot where each limb comprises two actuators with a sequence embedded in their hardware. The robot is able to carry pay loads of 800 g in addition to its own weight and is able to walk at travel speeds of 3 body lengths per minute, without the need for complex on-board valves or bulky tethers. ispartof: ADVANCED MATERIALS vol:31 issue:3 ispartof: location:Germany status: published

This paper proposes a novel approach for nonlinearity detection in vibrating systems. The approach is developed based on a new concept recently proposed by the author known as nonlinear output frequency response functions (NOFRFs) and the properties of the NOFRFs for nonlinear systems with multiple degrees of freedom (mdof). The results of numerical simulation studies verify the effectiveness of the approach. Nonlinear components often represent faults in practical mdof systems including beams. The proposed approach therefore has significant potential in the fault diagnosis of practical mdof engineering systems and structures.

Based upon the conservation of average energy a theorem about the periodic solutions of strongly nonlinear nonautomous systems with multi-degree-of freedom is proved. This theorem can not only decide the existence and stability of the periodic solutions, but at the same time can also give their first-order and second-order approximate expressions.

This study considers the dynamic response of electrostatic actuators with multiple degrees of freedom that are driven by multiple voltage sources. The critical values of the applied voltages beyond which the dynamic response becomes unstable are investigated. A methodology for extracting a lower bound for this dynamic pull-in voltage is proposed. This lower bound is based on the stable and unstable static response of the system, and can be rapidly extracted because it does not require time integration of momentum equations. As example problems, the dynamic pull-in of two prevalent electrostatic actuators is analyzed.

A twisted wire actuator, whereby the shortening of the length of a wire or a bundle of wires (20,21,22), as it is twisted, is used to control the motion of an actuated element, achieving sub-micron motion resolution. The control can be performed robotically. The high resolution can be achieved without the use of gears, sliders, or high precision lead screws, thus enabling a simplified actuation system and eliminating sources of friction. The use of wires (20,21,22) operating in opposing directions and having oppositely directed rotations significantly reduces the non-linearity effect inherent in twisted wire actuation, resulting in a system having a good level of motion linearity as a function of control input impulse. The use of multiple twisted wires (20,21,22) attached to the actuated element at different angles, enables the implementation of robotic systems with multiple degrees of freedom. Several experimental actuators verify these results.

In this paper with the use of conservation of average energy, a newmethod for computing the periodic solutions of strongly nonlinearautonomous systems with multi-degree-of-freedom is suggested. Thismethod cannot only decide the existence, but also give the approximateexpressions of the periodic solutions.

Predicting the actions of muscles controlled by the nervous system allows understanding how movement is generated in humans and animals. Computational neuromusculoskeletal models use surface electromyography (EMG) to “drive” simulated muscles to predict the resulting joint moments produced during dynamic tasks. We present a hybrid EMG-driven/EMG-assisted musculoskeletal model of the human lower extremity that addresses the main limitations of current EMG-driven methods. The new model estimates activation patterns for muscles from which EMGs cannot be measured and adjusts experimental EMG recording that may be subject to measurement errors, while calculating joint moments from multiple joints with multiple degrees of freedom. The model ensures dynamically consistent solutions, estimating the dynamics of 34 muscles and the resulting joint moments simultaneously produced around six degrees of freedom in the human lower limb. We describe the theoretical aspects of the proposed methodology and present experimental results that demonstrate the benefits of the new method.

For optimal performance, actuators designed for biologically-inspired robotics applications need to be capable of mimicking the key characteristics of natural musculoskeletal systems. These characteristics include a large output stroke, high energy density, antagonistic operation and passive compliance. The actuation properties of dielectric elastomer actuators (DEAs) make them viable for use as an artificial muscle technology. However, much like the musculoskeletal system, rigid structures are needed to couple the compliant DEA layers to a load. In this paper, a cone DEA design is developed as an antagonistic, multi-DOF actuator, viable for a variety for biologically-inspired robotics applications. The design has the advantage of maintaining pre-strain through a support structure without substantially lowering the overall mass-specific power density. Prototype cone DEAs have been fabricated with VHB 4910 acrylic elastomer and have characteristic dimensions of 49mm (strut length) and 60mm (DEA diameter). Multi-DOF kinematical outputs of the cone DEAs were measured using a custom 3D motion tracking system. Experimental tests of the prototypes demonstrate antagonistic linear (±10mm), rotational (±25°) and combined multi-DOF strokes. Overall, antagonistic cone DEAs are shown to produce a complex multi-DOF output from a mass-efficient support structure and thus are well suited for being exploited in biologically-inspired robotics.

In this paper, we present a versatile MEMS gripper capable of two-dimensional manipulation. This is accomplished by a multiple degrees of freedom electrothermal actuator which can achieve independent in-plane and out-of-plane motions. The device is fabricated with the MetalMUMPs process, which offers silicon nitride, polysilicon, and nickel as the major structural materials. The electrothermal actuator achieves large movement. The in-plane and out-of-plane tip displacements are 83.7 ?m at 0.6 V and 98 ?m at 87.2 V, respectively.

This paper deals with a new mechanism and the experiments of a 6 D. O. F. micromanipulator based on electrostatic actuations. This proposed micromanipulator is aiming at applications of biotechnology, microsurgery, and nanotechnology. Since operations in these fields grow rapidly and complicatedly, movable dexterous micromanipulators with multiple degrees of freedom such as 6 D.O. F. are desired. The salient features of this microactuator/manipulator are that: (1) it is structurally very compact since this micromanipulator is fabricated and assembled using methods of the photoetching process; (2) it has six degrees of freedom for motion control: the manipulator can move along three axes, and can also rotate along each axis; (3) it is easy to make the entire actuator. This paper demonstrates some of the static motions of the new actuators, and these functional merits will make it possible to operate the micromanipulator in a much more complicated environment under the microscope.

A method to estimate the standard deviation of eigenvalue and eigenvector of random multiple degrees of freedom (MDOF) systems is presented. This method can be applied not only to the MDOF systems with distinct eigenvalues, but also to the systems with multiple eigenvalue. Results for a beam and a truss are presented.

We present the design and development status of the opto-mechanical sub-systems that will be used in an experimental demonstration of imaging systems for eLISA. An optical bench test bed design incorporates a Zerodur® baseplate with lenses, photodetectors, and other opto-mechanics that must be both adjustable - with an accuracy of a few micrometers - and stable over a 0 to 40°C temperature range. The alignment of a multi-lens imaging system and the characterisation of the system in multiple degrees of freedom is particularly challenging. We describe the mechanical design of the precision mechanisms, including thermally stable flexure-based optical mounts and complex multi-lens, multi-axis adjuster mechanisms, and update on the integration of the mechanisms on the optical bench.

We propose to create a class of articulated micromanipulator robots with multiple degrees of freedom, workspaces on the order of a cubic millimeter, and payloads on the order of a milligram. We have created rigid links, mechanical couplings, and large-force, large-displacement micromotors. Hollow triangular beams made from rotated microhinged polysilicon plates can withstand axial loads of up to 2.3 gm. Mechanical couplings are used to rotate folded structures off the substrate with less than 2μN of force. Linear electrostatic stepper motors with an estimated force of 6.5μN at 35V and a travel of 40μm have also been demonstrated.

The popularity of minimally invasive surgical (MIS) procedures over traditional open procedures motivates us to develop new instruments that address the limits of existing technology and enable more widespread use of minimally invasive approaches. Robotic surgical instruments have the potential to provide improved dexterity and range of motion within the confines of the human body when compared with manually actuated instruments. The high strain response of electron-irradiated p(VDF-TrFE) copolymer makes it a candidate actuator material for robotic instruments that provide electronic mediation and multiple degrees of freedom of tip movement. We are currently studying both active and passive viscoelastic properties with the end goal of constructing a mathematical model to simulate the behavior of this material as an actuator. Studies have been conducted on 15 micron thick samples in rolled and rolled-flattened configurations. Active responses indicate approximately 2.5% strain in a 93 MV/m electric field under lightly loaded test conditions. Passive properties can be modeled by a 5 parameter viscoelastic model with two time constants of approximately 12 and 193 seconds. Current studies are examining means of combining active and passive properties in a simple model that can aid in design of a control system for the robotic actuators.

We present a novel approach to construct 3-D 1×N rotary micromirrors, which are fundamental components in optical switching systems. A rotary micromirror consists of two microparts: a rotary micromotor and a micromirror. Both of the two microparts are fabricated with PolyMUMPs,TM (MEMSCAP, Research Triangle Park, North Carolina), a surface micromachining process. A sequential robotic microassembly process is developed to join the two microparts together to construct the 3-D device. To achieve high positioning accuracy and strong mechanical connection, the micromirror is joined to the micromotor using an adhesive mechanical fastener. The mechanical microjoint has self-alignment capability and provides a temporary joint between the two microparts. The adhesive bonding creates a strong permanent connection between the two microparts. The adhesive mechanical fastener does not require extra supporting plates to fix the micromirror, which simplifies the microassembly process and makes it possible to automatically assemble the rotary micromirror. A hybrid manipulation strategy, which includes pick-and-place and pushing-based micromanipulations, is utilized to assemble the micromirror onto the micromotor. The pick-and-place manipulation has the ability to globally position the micromirror with multiple degrees of freedom. The pushing-based manipulation can achieve high positioning accuracy. This novel approach provides great flexibility and high accuracy for assembling the complex micromirror.

This paper deals with the coordination force distribution at finger joints for an articulated hand, under the assumption that the articulated hand with multiple degrees of freedom and a multiple articulated joint structure grasps some objects. In this study, four algorithms for this force distribution problem in grasping some object are derived from the static equilibrium conditions. Furthermore, a method for changing contact and non-contact fingers in grasping is derived and some simulations are shown, where changing fingers implies that some non-contacting fingers begin to make contact with the object, while the other contacting fingers do not contact it, keeping the stable grasping conditions by hand as a whole. Finally, based on the proposed five control algorithms, a control flow of stable grasping methods for the force distribution at each joint is made for an overall control of the finger system by determining grasping forces to changing grasping fingers.

A dynamical system having multiple degrees of freedom and under parametric excitation is governed by a system of ordinary differential equations with periodic coefficients. In this paper a first-approximation analysis is carried out and criteria for instability are derived explicitly.

A beam attached to a multiple degrees of freedom system is a common and complex structure in a broad field of engineering and science. The paper presents a novel and efficient computer model for dynamic analysis of a cantilever beam structure attached to a multiple degrees of freedom system by means of the recurrence matrix method. In this model, the forced responses and natural characteristics of the coupled beam are achieved and numerical simulations of the established model agree well with the early results. Finally, the vibration reductions of a beam by a dynamic vibration absorber are numerically studied.