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In vascular interventional surgery (VIS), the doctors often need to be exposed to X-ray radiation for a long time, operate surgical instruments (Ex. Guidewires and catheters) to perform the operation, which is difficult to ensure the health of surgeons and the safety of operation. In addition, the force between the blood vessel wall and the surgical instrument is complex and variable, the existence of the external disturbance forces easily affects the judgment of the doctors. In this paper, to ensure the health and reduce the fatigue of the doctors, a novel tactile sensing robot-assisted system for VIS was developed to assist the surgeons to complete the operation. Then, the forces between the blood vessel and the surgical instrument during the surgery were analyzed. Besides, a self-developed force sensor was used to confirm the collision force between the tip of the catheter and the blood vessel wall. Finally, combining the haptic force feedback of the system and the developed force sensor, a series of experiments in “Vitro” were completed, and it was indicated by the experiment results that the accuracy of the force feedback can be improved by using the analysis method proposed in this paper, the collision force between the catheter tip and the blood vessel environment can be confirmed by the self-developed force sensor. Based on the results, the developed robot-assisted system for VIS has high safety.

In the present study, the over-constrained hybrid manipulator R(2RPR)R/SP+RR is considered as the research objective. In this paper, kinematics of the hybrid manipulator, including the forward and inverse position, are analyzed. Then, the workspace is checked based on the inverse position solution to evaluate whether the workspace of the hybrid manipulator meets the requirements, and the actual workspace of the hybrid robot is analyzed. After that, the force analysis of the over-constrained parallel mechanism is carried out, and an ADAMS-ANSYS rigid-flexible hybrid body model is established to verify the simulation. Based on the obtained results from the force analysis, the manipulator structure is designed. Then, the structure optimization is carried out to improve the robot stiffness. Finally, calibration and workspace verification experiments are performed on the prototype, cutting experiment of an S-shaped aluminum alloy workpiece is completed, and the experiment verifies the machining ability of the prototype. This work conducts kinematics, workspace, force analyses, structural optimization design and experiments on the over-constrained hybrid manipulator R(2RPR)R/SP+RR, providing design basis and technical support for the development of the novel hybrid manipulator in practical engineering.

Using robotic capsules for assessing gut health has been an emerging field since the early 2000s with researchers attempting to perform diagnosis, monitoring, and therapeutic functions inside the gut. The knowledge of peristaltic forces inside the intestine are crucial for designing the actuation mechanism of robotic capsules, however, the impact of peristalsis on a capsule has not yet been quantified. In this work, an analytical model is presented to study the peristaltic movement of the small intestine. For the first time, finite element simulations were conducted in COMSOL multiphysics to generate intestinal peristaltic forces, and analyze their impact on a robotic capsule. A capsule prototype (30 × $\phi$ 12 mm) was developed to measure the peristaltic forces from living intestinal tissue, while an embedded system was used simultaneously to record the live data from the capsule-intestine interaction. In in vitro experiments, the intestine applied an average axial force of 226 mN and contraction cycles of 9 times/min, while the capsule prototype experienced maximum radial force of 180 mN. A specialized in vitro setup is developed to keep fresh ex vivo intestine samples alive for up to 6 h, while the capsule prototype measured the intestinal forces from the living tissue. This in vitro experimental setup provided an excellent model for the in vivo environment in terms of generating peristaltic movements, hence this force analysis will help in developing efficient prototypes for locomotion, anchoring, localization, biopsy, drug delivery, and sampling mechanisms for robotic capsules.

Due to the unclear application scenarios and force analysis of exoskeletons, there exists a research gap in exoskeleton design. This paper presents a design method and realization of an exoskeleton for a specific scenario of lifting a load in situ. Firstly, the lifting motion process and its data were collected based on a 3-D motion capture system and dynamometer treadmill system. Then, the variations of the torque and motion of each joint were obtained from the data analysis, based on which an active assistance mode for upper limbs and a passive assistance mode for lower limbs were demonstrated. In this design, the hydraulic cylinder for shoulder assistance, the motor for elbow assistance, and the spring for lower limb assistance were calculated and selected according to the motion and torque of each joint. Finally, subjective and objective methods were used to evaluate the exoskeleton based on the results of five test participants, and the median oxygen consumption of the whole test by lifting a load ten times with the assistance was found to be reduced by 9.45% as compared with that in the absence of the exoskeleton.

SUMMARYThis paper presents a methodology to obtain the wrench capabilities of a kinematically redundant planar parallel manipulator using a wrench polytope approach. A methodology proposed by others for non-redundant and actuation-redundant manipulators is adapted to a kinematically redundant manipulator. Four wrench capabilities are examined: a pure force analysis, the maximum force for a prescribed moment, the maximum reachable force, and the maximum moment with a prescribed force. The proposed methodology, which finds the exact explicit solution for three of the four wrench capabilities, does not use optimization and is very efficient.

The linear induction motors, due to their unique features, utilize in various applications. The most crucial drawback of the linear induction motors is the large air gap between secondary and prima...

The results of kinematic and force analysis of the new six-link converting mechanism of the sucker rod pumper drive (SRPD) are presented in this paper and the advantages of the alternative design are substantiated. Using a straight-line generating mechanism allows reducing essentially converting mechanism dimensions and metal consumption as compared with traditionally used SRPD with swinging balancer and crank-based counterweight, first of all, due to eliminating the complicated arc head (so-called «horse-head») of the existing units. However, in order to make sure the working capacities of non-balancer mechanism, kinematic and force characteristics have to be studied. The results of mathematical modeling of the six-link mechanism confirm the qualitative advantages of the straight-line generator. As a result of the study of the rectilinear-guiding mechanism as a transforming mechanism for the drive of sucker rod pumping units, the laws of motion of the links, position, speed and acceleration of all points were determined. To solve the problem of kinematic analysis, the method of closed vector contours was used, which makes it possible to determine the functions of the position of links and analogs of speeds and accelerations. When solving the problem of strength analysis, the equilibrium of each link was considered. As a result of force analysis, jointly solving the equilibrium equations of the links of the six-link hinge-lever mechanism, the reactions of the hinges of the mechanism are determined. A computer model for studying the kinematics and kinetostatics of the converting mechanism of the sucker rod pumping unit drive has been developed

The double-layer approach (DLA) possesses superior features for the analysis of static electromagnetic problems. In this article, dealing with the magnetostatic analysis, we introduce two kinds of double layers: the first one on the surface of the magnetic body and the second one on the cut-surface within the exciting current loop. From the double layers on the cut-surface, we were able to derive a novel, unified exciting potential, which facilitates the treatment of any magnetostatic problem, including multiply connected problems. Furthermore, in this article, we use for the first time DLA for the analysis of magnetic forces acting on the magnetic bodies. The law of action and reaction provides a self-check function within DLA, enabling thus the simple and reliable tool for the confirmation if the computed results are adequate and accurate. This improved, DLA-based approach for the force analysis together with the introduced “action-reaction” principle for the self-checking of the force calculation are, to the authors' best knowledge, not known in the scientific community so far. Finally, we would like to emphasize that the presented DLA enables accurate, self-checked, generic analysis of the real-world devices, providing advanced treatment of both geometrical singularities (edges, corners) and materials used (high permeability, nonlinearities).

BACKGROUND Artificial anal sphincter (AAS), as an advanced device, has been widely investigated by researchers around world. But the reliability of the structure is still unsatisfactory according to clinical results. What's more, the previous AAS systems are lack the ability of rectal perception as native anal sphincter, which fails to guarantee the safety of the blood supply. In addition, without it, the patient cannot determine when to defecate. METHODS In order to improve the reliability and safety of current artificial anal sphincter systems, a novel structure artificial anal sphincter system with rectal perception function, based on pressure sensor module, is proposed in this article. The novel AAS system has a closed three-arm clamping mechanism, with transmission structure of cam-follower system. Then, the design, strength check, optimization and force analysis of the proposed mechanism are investigated. After that, to remodel rectal perception function, the novel sensor module system based on strain gauge is established. Finally, in vitro experiments are conducted, RESULTS: In vitro test, the sensor system could monitor the rectal pressure accurately. And when H=24.6cm (feeling the urge to have a bowel movement), the clamping pressure is 7.39kPa. which is also less than the safe pressure 9.33kPa. CONCLUSIONS Good performance of the reliability and safety of both novel rectal perception function and new clamping mechanism have been showed.

Stability plays a vital role in any robotic system. Its significance increases in systems related to health and medicine. For rehabilitation devices meant for Spinal Cord Injury (SCI) patients, stability is crucial and key element in ensuring patient safety and the usefulness of the devices. In this study, kinematics, force analysis, and the static tip-over stability of a device for rehabilitation of paraplegic patients is discussed. Kinematics modeling and static force analysis provide critical information about position and loading at different points on the device. Force-Angle Stability Criterion is used to find the static tip-over stability of the device while the patient is on board the device. The Criterion relies on the support boundary, tip-over mode axes, and the Center of Mass (COM) of the complete system. The Criterion is sensitive to the COM position and therefore is more suitable for the application. The linear actuator mounted on the device causes the end effector of the device to move. The patient, strapped with the end effector, in turn moves from sitting position to standing position. The study focuses on the analysis of stability based on changing COM during this motion. The results verify that although the system is well within the stability bounds, it is more stable as it moves from sitting position to standing position.

At present, the vascular interventional surgery has attracted more attention. Because it has the advantages of smaller trauma, lower pain, and quicker recovery after the operation. As for the design of the clamping mechanism, fast and lossless clamping of the catheter has always been a hot and difficult point in the current research. In this paper, a novel slave manipulator is introduced (contains coordinate system). It simulates the twisting of human fingers for the catheter during the actual vascular interventional surgery. Moreover, we evaluated its clamping form. Simulation results show that: From the angle of total deformation, strain, and stress, it is analyzed that there is no damage to the catheter; From the point of view of the clamping force analysis, it is obtained that the clamping force is enough to guarantee the forward and backward of the catheter; From the perspective of conflict protection, the size of the clamping force can be changed by adjusting the clamping depth. In this way, the tip of the catheter can be avoided puncturing the vessel wall, thus increasing the actual clinical safety performance.

Rubber tire loaders are key loading equipment for surface and underground mines and can load up to 35 t of material in a pass. Efficient initial penetration into the pile improves the overall efficiency of the loading operation. For efficient design for good initial penetration, we need to predict accurately the resistive forces encountered by these buckets during initial penetration. This paper examines the resistive forces on the bucket as a function of rake angle, height above the digging floor, speed, and tractive effort during initial penetration. A 1/16th scaled representative model of an 18 t (19.8 ton) capacity load haul dump is used for experimentation to understand the effects of rake angle, height above the floor, speed, and tractive effort. The results show that resistive forces are not associated with rake angle or height above the floor but significantly associated with speed, tractive effort, combined effects of speed and tractive effort, and combined effects of speed and rake angle. Future research should focus on conducting similar experiments on different materials and different buckets to better understand the ground engagement for mining and construction equipment. These insights are important to understand the full range of forces during bucket and equipment design.

A cable-driven hyper-redundant manipulator receives great attention due to its slender body and flexible movement. The configuration of the driving cable is the key to manipulator design. At present, cables are arranged at equal angles on the disk, but it lacks theoretical support. The analysis about the influence of cable positions on cable tensions is relatively deficient. In this paper, the force on links is studied. The influence of cable positions on driving force is analyzed. The relationship between cable position, driving force, external force and joint angles are studied. Numerical simulation is carried out to verify the theoretical analysis. The results show the maximum of driving forces is the smallest when cables are arranged at equal angles and decreases as the cable position becomes uniform. The results explain the rationality of the equal configuration of the cables in the cable-driven hyper-redundant manipulator. It’s beneficial to guide the design of cable-driven manipulator.

This paper proposes an electronic trigger assisted coupled and self-adaptive finger, LPCA finger. LPCA finger is provided with two joints, two motors, two sensors and a control module, which realizes coupling during the startup phase of grabbing and self-adaptive in the next stage. According to its self-adaptive characteristics, the device can grasp the target of uncertain size and type. The pressure sensor is used to collect the information of the object contacted by the phalanges, and the second motor can be triggered to cooperate with the assistance of self-adaptive grasping with only a small extrusion pressure to avoid the damage caused by excessive extrusion pressure on the object caused by the proximal phalange in the grasping process. The finger end grasping force is large and the structure is simple. This paper introduces the design of LPCA finger, and gives the force analysis of finger. Force analysis and experiments indicate that LPCA finger possess coupled and self-adaptive function and its end grasping is stable.

In order to improve the overall strength of the aerial winch drum and reduce the weight of the drum further. The mathematical model of the cable tension acting on the winch drum is built based on the force balance formula, and the relationship between the cable tension and the cable winding layers is analyzed. The multi-layer winding coefficient equation is established according to the actual cable arrangement on drum, MATLAB is used to solve the equation. The simulation results show that the multi-layer winding coefficient increases as the number of winding layers, but the growth rate decreases gradually. When the number of winding layers exceeds a certain value, the multi-layer winding coefficient tends to be stable, and the tension of the inner and outer layers of the cables wound on the drum is larger. This algorithm can be effectively applied to the structural design of aviation winch drum, and provide theoretical basis for practical engineering design.

In order to ensure the smooth, reliable and safe driving of intelligent vehicles, this paper combines the driving state information and energy transfer information of vehicles in traffic environment, builds a three-degree-of-freedom vehicle dynamic model and force analysis, and verifies it by software simulation. The results show that the dynamic model and control algorithm can ensure the safe driving of intelligent vehicles under complex constraints such as high speed, slip and roll, and effectively consider the influence of road curvature and terrain on the dynamic characteristics of high-speed vehicles to ensure collision-free driving. Hardware-in-the-loop simulation can connect the rapid prototype hardware system with the actual equipment to be controlled, and can repeatedly study the performance characteristics of the system when using different sensors and driving mechanisms .

A newly developed prototype of a soft cable-driven elbow exoskeleton for lifting and lowering of loads was developed. To identify potential harmful forces within the elbow joint, an analysis was conducted with biomechanical simulation. To analyze the effect of the exoskeleton on the human body, biomechanical simulations were conducted on the prototype to assess the joint reaction forces during a lifting task with and without the soft elbow exoskeleton. To reduce these forces, the optimal way to attach the cables for generating the moment around the elbow needs to be identified using biomechanical simulation. First results show that in average the load on the elbow joint is reduced while wearing the exoskeleton compared to lifting 5 kg without any assistance. A large distance between the lower arm and the attachment point in ventral direction is very beneficial, due to the introduction of another lever arm into the system. Especially if the elbow is fully stretched, whereas the pulling force vector would go parallel to the arm. With the implementation of the lever arm, the load on the elbow is lower for any position of the arm.

The return capsule needs to be launched to the moon and return back to earth in the third stage of the Chinese lunar exploration project. Therefore, it is necessary to perform simulations on the ground. This paper presents an 8-cable-driven parallel manipulator to achieve end-force output in a low-gravity environment. End-force output refers to the vector sum of the external force on the end-effector. A model of end-force output is established based on a kinematics model, a dynamic model, and a force analysis of an 8-cable driven parallel manipulator. To obtain end-force output in a low-gravity environment, the cable force has to be controlled to counteract gravity. In addition, a force-position mix control strategy is proposed to proactively control the cable force according to the force optimal distribution given by the closed-form force distribution method. Furthermore, a suitable choice for an end-force output is obtained by modeling the effect of cable force on end-force output. Experimental results show that the actual cable force agrees well with the calculated force distribution, indicating that it is feasible to realize end-force output in a low gravity environment.

The diffusion of Internet-based Intangible Network Goods (IINGs) shows new characteristics completely different from that of traditional material products. This paper aims to establish new models t...

Assembly-level geometric errors such as backlash, center distance errors and shaft misalignments may adversely affect the operation of a gear train. The tolerance analysis method proposed in the paper estimates these errors from tolerance specifications on gears and mounting parts (shafts, bearings, housings). The problem is solved by analogy with an equivalent problem of force analysis: on a properly defined structure, external forces correspond to the assembly-level error, and calculated internal forces and support reactions provide the sensitivities of part tolerances on the total error. Previously developed for generic assemblies, the approach proves especially simple for gear systems compared to existing methods of tolerance analysis, as it relies upon structural analysis procedures that are customary in mechanical design. The method based on static analogy includes a two-level classification of geometric errors, which helps overcome the complexity of tolerance analysis problems for gearings. Two examples of gear trains of different types and configurations are presented to demonstrate the calculation procedure and verify its correctness by comparison with geometric considerations.

This paper proposes a method for designing the ram structure of friction stir welding (FSW) robots using finite element analysis. Under the given working condition, force analysis for the ram struc...

Simultaneous assembly of multiple objects is a key technology to form solid connections among objects to get compact structures in precision assembly and micro-assembly. Dramatically different from traditional assembly of two objects, the interaction among multiple objects is more complicated on analysis and control. During simultaneous assembly of multiple objects, there are multiple mutually effected contact surfaces, and multiple force sensors are needed to perceive the interaction status. In this paper, a coordinated micro-robot manipulation strategy is proposed for simultaneous assembly problem, which is based on microscopic vision and force information. Taking simultaneous assembly of three objects as an instance, the proposed method is well articulated, including calibration of assembly system, force analysis for each contacting surface, and insertion control strategy for assembly process. The proposed method is applicable also to case with more objects. Experiment results demonstrate effectiveness of the proposed method.

The purpose of this study is to present a forward kinematics model of the human lumbar spine and to compare the internal loads and trunk flexion extension with existing literature. The forward kinematics model of lumbar spine with 30 DOF was designed using Solidworks and used Matlab to simulate the results for different postures. The forward kinematics model predicted similar trend for trunk flexion extension, compression force, shear forces and moment as described in literature for in vivo studies. The comparison between the proposed model and in vivo measurement showed a pressure difference of less than 15% on the disc L4-L5 for all activities whereas the compression force and moment differed by ~17% on the disc L5-S1. The modeling methodology presented in this thesis provides a more accurate representation of compression forces and moments of the human lumbar spine since the model makes no assumptions regarding muscle force and does not rely on any other software for kinematics data.

A kinematic chain with two degrees of freedom and one input can have definability of motion only if there is an additional constraint of forces and velocities. Such a chain is a mechanism that has the brand new property of force adaptation. The article presents a kinematic and force analysis of two-mobile adaptive mechanisms and describes the principle of definability of motion.

This paper presents the design, analysis and development of an anthropomorphic robotic hand, i.e. MCR-Hand III. Based on the investigation of human hand anatomical structure and the related existing robotic hands, mechanical design of the MCR-Hand III is presented. Then, a detailed introduction for mechanical compliance of the hand is provided, which is achieved through the combinations of springs with four-bar 4R linkages and tendons. Using D-H convention, kinematics and force analysis of the hand are formulated and illustrated with numerical simulations, laying background for comparison and evaluation. Subsequently, a prototype of the proposed robotic hand is developed, and fingertip force calibration and validation are conducted. Further, a three-stage algorithm for object stiffness identification and adaptive grasping is proposed and evaluated, and grasping evaluation based on the Cutkosky taxonomy with additional deformable object lifting operation and piano manipulation is carried out. The proposed MCR-Hand III costs less than $800 and is hence affordable for wider applications. The experimental results indicate that the proposed hands are capable of implementing the grasp and manipulation for most of the objects used in daily life.

The Rędziński Bridge in Wrocław is the biggest Polish concrete cable-stayed bridge. It is equipped with a large structural health monitoring (SHM) system which has been collecting the measured data since the bridge opening in the year 2011. This paper presents a comparison between the measured data and the finite element method (FEM) calculations, while taking into account 7 years of data collection and analyses. The first part of this paper concerns the SHM application. In the next part, which contains comparisons between forces in cables and temperature changes throughout the structure, the measured data are presented. The third part includes SHM-based calculations and simulations with a complex FEM model to check the measured data and to estimate future measurements. The last part contains a durability assessment calculation for the cable stays.

Experiments with a cam-type clamp tool were carried out to overcome the difficulty of transporting and installing large-diameter mono-piles for offshore wind turbines. Using the experiments method to design a small wedge-type clamping mechanism and using cam teeth made of 40Cr material resulted in the maximum friction for the mechanism. A single clamping design was created for the cam-type clamp tool to hoist mono-piles for offshore wind turbines. Through force analysis and Automatic Dynamics Analysis of Mechanical System (ADAMS) dynamic simulation of the lifting tool, it was calculated that the clamping force of the lifting tool meets application requirements. A prototype was built in order to carry out an experiment in which the lifting tool hoisted a mono-pile. It was concluded from the experiment that the proposed design of the lifting tool is feasible in practical applications.

Simulation is an important way to verify the feasibility of design parameters and schemes for robots. Through simulation, this paper analyzes the effectiveness of the design parameters selected for a tomato picking manipulator, and verifies the rationality of the manipulator in motion planning for tomato picking. Firstly, the basic parameters and workspace of the manipulator were determined based on the environment of a tomato greenhouse; the workspace of the lightweight manipulator was proved as suitable for the picking operation through MATLAB simulation. Next, the maximum theoretical torque of each joint of the manipulator was solved through analysis, the joint motors were selected reasonably, and SolidWorks simulation was performed to demonstrate the rationality of the material selected for the manipulator and the strength design of the joint connectors. After that, the trajectory control requirements of the manipulator in picking operation were determined in view of the operation environment, and the feasibility of trajectory planning was confirmed with MATLAB. Finally, a motion control system was designed for the manipulator, according to the end trajectory control requirements, followed by the manufacturing of a prototype. The prototype experiment shows that the proposed lightweight tomato picking manipulator boasts good kinematics performance, and basically meets the requirements of tomato picking operation: the manipulator takes an average of 21 s to pick a tomato, and achieves a success rate of 78.67%.

Gait analysis is a method for identifying biomechanical abnormalities in the gait cycle. It is a way of assessing the way in which we walk and run. Force analysis is critical during rehabilitation process of amputation patients, since overloading might place the bone-implant interface at risk, while under loading might extend unnecessarily the already long rehabilitation program. Highly developed sensor and data acquisition technology provides an easy and reliable way to do gait analysis. We will use IDEEA Life Gait sensor attached to the ankle, thigh and chest. The IDEEA system records data points of daily activities, and posture and exercise on 24 h basis analyze these data with high intelligence, detailed to every seconds, every move you made or every step you walked. The ActView (GaitView) program allows you to manage these data and view them in the form of charts, tables and curves.

Subway electric passenger cars have a large capacity, high efficiency, high-frequency door set control switch and other characteristics, so it requires the door safety, reliability, low failure rate. This paper mainly aims at the force analysis calculation and structural optimization of the fault of the screw break of the synchronous rod bracket, so as to avoid the same kind of fracture situation.

The paper puts forward a self-powered double-layer parking device, aimed at solving the problem of a serious shortage of parking space and transformational difficulty in older urban communities. The parking device was driven by the power of the car and driver, which can be accessed to cars independently. The detailed force analysis of the device was carried out thoroughly, which is combined with the structure and the driving principle of the device. Based on the parameters, the structure of the device was determined and the self-powered systems, satisfying the requirements, were designed. Taking the height of the column and the force point of wire, the analysis and research of dynamic simulation was accomplished, based on the ADAMS accomplished. The dynamic performance optimization design was obtained and the rationality and feasibility of the device were verified, too.

At present, robots are more and more widely used in various fields, especially in the medical field in recent years, the typical application field is laparoscopic surgery robot and neurosurgery robot, the advantages of robot high precision have been fully demonstrated in the operation. Because of the rapid development of surgical robot, the matching surgical instruments have also been developed accordingly. Because of the different types and structures of the robot, each kind of surgical robot needs to design special surgical instruments to match its function. This paper proposes a special two-degree-of-freedom (DOF) craniotomy surgery robot special instrument, which cooperates with craniotomy surgery robot to complete craniotomy operation.

A generic evacuation model is developed based on the behavioral characteristics of passengers during bus fires. Inspired by hydrodynamic mechanisms, the proposed particle-based force-driven model is built using force analysis of evacuees and analogs the movement of people as fluid motion. Several modules are developed to characterize evacuees’ preferences for varying exits, aggregated behavior of groups, and effects of driver. The Smoothed Particle Hydrodynamics (SPH) methods are applied to solve the proposed model using smoothed kernel functions. Experiments are conducted to calibrate and validate the proposed model based on observed evacuees’ behavioral characteristics, such as evacuation time, evacuation speed under different scenarios in terms of bus capacity, and the interaction between evacuees. The results of the study will contribute to a better understanding of bus evacuation options, improved design of bus vehicles to cope with internal fires, and the development of appropriate policies and regulations for bus passenger evacuation in response to fires. The proposed method can also be readily applied to other related fields with minor modifications.

Launching technology with rocket booster is widely used in the launching process of UAV. In this paper, the process of short rail launch with rocket booster was divided into three phases. Through the force analysis of all the phases, a complete mechanical model of the whole launching process was established. Then the short rail launch of an UAV was taken as an example, and the influence of rocket installation angle, UAV emission angle and the effective length of short rail on launching process was analyzed, and the appropriate launching parameters were selected. After that, the attitude changes of UAV when the rocket thrust doesn’t pass through the center of gravity were obtained and compared with that of zero-length launching process. The results show that due to the constraint of short rail, the flight attitude variation range of UAV during the launching process is smaller than that of zero-length launch, which is more conducive to the launching safety.

The analysis of the mechanical characteristics of the knee flexion movement can effectively improve the athlete’s competitiveness and provide an important theoretical basis for the study of human mechanics. The human knee is an important analysis goal. In the force analysis of the flexion movement of the athlete, the flexion movement characteristics of the knee joint of the athlete are mainly analyzed. The traditional biological method only analyzes the force of all the human joints in the athlete, but ignored the athlete’s knee test. In this paper, we propose a method to analyze the mechanical characteristics of knee flexion movement in the human body. Taking the throwing movement as an example, the professional far-infrared system is used to test the whole process of the flexion movement of the athletes and the mechanics model of multi-rigid body is established to carry out the mechanical characteristics analysis of the knee flexion movement, and analyze the knee force situation of the athletes under different movements in detail. In order to verify the effectiveness of the proposed method, the experiment is carried out. From the experimental results, it can be seen that the method for researching the mechanical characteristics of the knee flexion movement can be used to effectively analyze the knee force.

Because of the high prices and difficulties to conduct short-current tests of large power transformers, it is meaningful to analyze the dynamic electromagnetic force analysis of the transformer windings through finite element software. Research in this paper presents a model of the 50000MVA/110KV three phase transformer established by COMSOL. Different conditions of short-circuit current are applied to the model, testing the dynamic electromagnetic forces of the transformer windings. Results of the paper may be useful for investigating the winding deformation state prediction.

This paper presents a simulation result of dynamic reaction forces on the slave-arm revolute joint of the mechanical master-slave manipulator for remote handling of radioactive materials and nuclear processing. The dynamic modeling of the manipulator is established in the multi-body dynamics(MBD) simulation S/W of RecurDyn to verify the gear tooth contact force and bearing reaction forces on the revolute joint of its slave-arm on condition of the maximum handling load. For modeling the detailed parts of the revolute joints , two stages gear transmission; one bevel gear-pair and the other spur gear pair, and two support rolling bearings are defined with mechanical properties. As results of the force analysis, the reaction forces on gearing and bearings which are used to address the improvement of the joint design are shown for the manipulator.

There are ample literature addressing the dynamic analysis for gears. In this paper, some important literature on dynamics of both healthy gears and gears with defects have been reviewed. Dynamic analysis of gears is significant from the condition monitoring point of view. Single degree of freedom dynamic model for spur gears has been detailed first. Dynamic study for worm gear with force analysis has been reported. Also, the effect of defects like crack and spall on dynamic behavior of gears studied by researchers has been included in this review. The study of defect model can be utilized in improving the efficiency of the system and preventing the failures in industries as well.

Further the large deformation problem of compliant mechanisms is investigated in this chapter. As has been discussed in Sect. 4.4.4, when a compliant mechanism is under a large external load, the corresponding stiffness matrix is no longer symmetric and invariant. However, its force equilibrium still holds the same and it is used here to explore the compliant mechanism’s large deformation properties. It is straight forward to conduct inverse force analysis of compliant serial mechanisms and forward force analysis of compliant parallel mechanisms. However, additional consideration is needed for compliant mechanisms that have mixed configurations. In accordance with this, a repelling-screw based force analysis approach is developed in this chapter, making it possible to conduct a forward force analysis of compliant mechanisms that have hybrid combinations of flexible elements. This proposed force-modelling approach is further applied to analyze the large deformation behaviours of origami-inspired compliant mechanisms. An origami-inspired compliant mechanism is a foldable structure that consists of both panels and creases, which can be treated as an equivalent mechanism by taking panels as links and creases as revolute joints. Thus an origami mechanism can be treated as a parallel mechanism with revolute joints. Section 8.2 presents a complete experimental test of single creases of origami folds, which reveals an origami crease can be treated as a one-DOF flexible element with embedded torsional stiffness. This paves the way for the further force analysis of origami compliant structures using the proposed repelling-screw based approach. The theoretical background of this approach is provided in Sect. 8.3 in the framework of screw theory, and it is utilized to conduct force analysis of several typical origami compliant platforms in the following Sects. 8.4 and 8.5 respectively.

The automatic charging of electric vehicles is an important but challenging problem. Recently, various charging robots are proposed for electric vehicles. Most previous researches do not pay enough attention to the robots&rsquo, load capacities. Actually, providing the charging connector with adequate pushing and/or pulling forces is vital to guarantee a reliable electrical connection, which is a key issue for charging robot design. In this paper, we present a novel serial-parallel robot for the automatic charging of electric vehicles. This robot is based on the 3 universal-prismatic-universal (3UPU) parallel mechanism and featured by high-load capacity. We firstly address the kinematic and static models of the proposed robot, then analyze its load capacity. It is shown that the robot&rsquo, s maximum load capacity depends not only on the driving ability of the prismatic joints, but also on the robot&rsquo, s structural parameters and the robot&rsquo, s configuration. Finally, optimizations are made and results show that the robot&rsquo, s load capacity along the desired trajectory has more than doubled. Results of this paper could be useful for the development of automatic electric-vehicle-charging devices.

Wheelchairs assist people with disabilities to become productive members of their communities. About 650 million people of the global population, have disabilities. Studies show that around 65 million of these require a wheelchair. The main purpose of the project is to design and develop a module that can be attached to any conventional wheelchair model in order to make it self-propelling. There are a wide variety of wheelchairs that are available in the market. However, the maneuvering of these wheelchairs by the patient himself and for an outsider is difficult and usually results in further injuries. Thus, considering these aspects we introduce this new design concept for a wheelchair which has a much simpler structure compared to the complex versions currently available in market. The module is designed to reduce the effort of wheelchair users during manual propulsion. It will be entirely electric and is a new concept of transportation for the disabled. The module was designed in Autodesk Fusion 360 and force analysis was carried out in ANSYS Workbench.

In order to improve the comfort of automobile seat, it is necessary to analyse and study the design method of automobile seat. A design method of adaptive automobile seat based on ergonomics principle is proposed. The height, width, depth, backrest, seat inclination and backrest inclination of automobile seat as well as the sitting posture physiology and body pressure distribution of human body are analysed. The frame of automobile seat is designed by using aluminium alloy in PROE software, the size of the energy absorption of headrest, cushion and seat are determined according to national regulations. By analyzing the back force, pillow force, seat belt force and seat belt locking, the force of automobile seat, the strength of back, head pillow and seat cushion of automobile seat are designed and the design of adaptive automobile seat is completed. The experimental results show that the proposed method has high comfort, low processing cost and high production efficiency.

Comparing with the tractor-trailer systems for the road haulage, which must cope with some typical undesired trends, such as high-speed instability, over- or under-steering and off-tracking, the multi-trailer systems for the transport of luggage in the airports or in the railway stations, or for the transfer of goods in the warehouses, run at quite low speeds, but must manage to steer clear of the many obstacles encountered along their path. This type of vehicle is not subject to tire cornering phenomena, because the speed is just low and the wheels are generally stiff. Hence, the vehicle movement is in practice ruled by the non-holonomic rolling constraint of the wheels and by the steering device mounted on the trailers, which may consist in drawbars integrated with the front axles and rotating around a central pin (dolly-semitrailer systems), or else in roulettes set back with respect to their vertical connection pins to the trailer chassis (caster-trailer systems). The present analysis addresses all the interconnected aspects of the mechanical behaviour of these types of multi-trailer systems in an organic whole, starting from the kinematical analysis of the possible paths and their stability, giving guidelines for the proper layout of the vehicle units to eliminate the steady off-track, and ending with the calculation of the traction forces through the various links and the road forces at the ground prints, in order to gain information useful to check the stress state of the various structural elements.

According to the principle of the gear overall size as small as possible, the structural analysis of multistage micro-planetary transmission is carried out. It is found that a 2K-H multistage micro-planetary gear reducer meets with the principle requirement. On this basis of the torque, power balance equations and force analysis of the basic members, the power distributions of a 2K-H multistage micro-planetary gear reducer are analyzed under considering power losses or not, the overall transmission efficiency calculation of a 2K-H multistage micro-planetary gear reducer is more intuitive and easy to operate. Meanwhile, it indicates a direction for further power losses analysis of multistage micro-planetary transmission.

New numerical strategies that reconsider tubing force analysis (TFA) in connection with buckling induced lock-up are presented and applied. The strategies introduce new visualizations of downhole instabilities in coiled tubings (CT) for the entire run-in-hole (RIH) process. Most extended reach interventions seek to reduce compressive forces experienced by the CT through usage of lubrication, vibrations or tractors, but little attention has been given to stabilizing initiatives that prevent buckling. A stabilizing initiative is anything that increases the critical helical buckling load of the CT, for example a reduction of radial clearance between CT and wellbore. The strategies presented allow us to (1) evaluate the gain in CT reach from stabilizing initiatives, and (2) automatically determine the minimum requirement for a stabilizing initiative that will bring the CT to the desired operational depth, when it is applied optimally along the length of a CT/wellbore. Thus, the strategies promote investigations of novel stabilizing solutions that can complement existing extended reach technologies. The developed TFA algorithm is validated against field data and the strategies are utilized on a wellbore in the Danish North Sea. The investigation showed that a stabilizing initiative that increases the critical helical buckling load by 31% when introduced into 35.57% of the wellbore length will extend CT reach from 69.72% to 100% into the payzone. With these strategies in place we present a new approach to optimize well utilization.

The force analysis of overconstrained PMs is relatively complex and difficult, for which the methods have always been a research hotspot. However, few literatures analyze the characteristics and application scopes of the various methods, which is not convenient for researchers and engineers to master and adopt them properly. A review of the methods for force analysis of both passive and active overconstrained PMs is presented. The existing force analysis methods for these two kinds of overconstrained PMs are classified according to their main ideas. Each category is briefly demonstrated and evaluated from such aspects as the calculation amount, the comprehensiveness of considering limbs’ deformation, and the existence of explicit expressions of the solutions, which provides an important reference for researchers and engineers to quickly find a suitable method. The similarities and differences between the statically indeterminate problem of passive overconstrained PMs and that of active overconstrained PMs are discussed, and a universal method for these two kinds of overconstrained PMs is pointed out. The existing deficiencies and development directions of the force analysis methods for overconstrained systems are indicated based on the overview.

Offshore cranes are widely used in offshore industry. However, because of the wave motion of the ship and the flexibility of the rope, the sway of payload is unavoidable and may put relevant operations in danger. Thus, compensation system is an essential part of offshore crane to ensure human safety and increase operation efficiency. In this article, a novel offshore crane combined compensation approach named four-post combined compensation is proposed based on the three-post direct ship motion compensation, aiming to overcome its shortcomings. The structure and principle of four-post combined compensation is introduced. The mathematical models of four-post combined compensation and three-post direct ship motion compensation are established uniformly and based on which we carry out numerical simulations and comparative analysis of three-post and four-post schemes. Numerical simulation results are included to demonstrate that comparing to three-post scheme, four-post scheme has the following advantages: first, the maximum actuator force requirement can be reduced significantly; second, the work load is distributed more evenly among cylinders; third, the main support shaft can prevent the platform from tipping over; the actuators always push the platform and do not have to be bi-directional, which might result in lower cost and risk.