The mathematics of coordinated control of prosthetic arms and manipulators.

Immune system can recognize self vs transformed self. That is why cancer immunotherapy achieves notable benefits in a wide variety of cancers. Recently, several papers reported that immune checkpoint blockade therapy led to upregulation of IFNγ and in turn clearance of tumor cells. In this review, we conducted an extensive literature search of recent 5-year studies about the roles of IFNγ signaling in both tumor immune surveillance and immune evasion. In addition to well-known functions, IFNγ signaling also induces tumor ischemia and homeostasis program, resulting in tumor clearance and tumor escape, respectively. The yin and the yang of IFNγ signaling are summarized. Thus, this review helps us to comprehensively understand the roles of IFNγ in tumor immunity, which contributes to better design and management of clinical immunotherapy approaches.

https://onlinelibrary.wiley.com/doi/pdf/10.1002/cam4.1700

Interferon gamma in cancer immunotherapy

The bridge-type flexure hinge is a classic displacement amplification mechanism The existing models of theoretic displacement amplification ratio of bridge-type flexure hinges are not perfect This makes it very difficult to design and manufacture a satisfactory structure using these models Kinematic theory was used to analyze the ideal displacement amplification ratio of a bridge-type flexure hinge in this paper, and the flexure hinge was regarded as a pure multi-rigid body with ideal pivots Elastic beam theory was used to analyze the theoretic displacement amplification ratio when considering the translational and rotational stiffness of the flexure pivots The model of theoretic displacement amplification ratio explains why the bridge-type displacement amplification mechanism has an amplification ratio extremum and where the threshold is The finite element method was used for comparison with the mathematical model, and similar results were obtained Finally, the finite element method was used to analyze the shape mode of the structure The result showed that increasing the amplification ratio by decreasing the thickness of the flexure pivots led to a decrease in the mode shape frequency of the bridge-type structure Thus, redesigning of the structure was needed to solve the problem

Analysis of the displacement amplification ratio of bridge-type flexure hinge

Carbon fibre reinforced polymer (CFRP) composites have excellent specific mechanical properties, these materials are therefore widely used in high-tech industries like the automobile and aerospace sectors. The mechanical machining of CFRP composites is often necessary to meet dimensional or assembly-related requirements; however, the machining of these materials is difficult. In an attempt to explore this issue, the main objective of the present paper is to review those advanced cutting tools and technologies that are used for drilling carbon fibre reinforced polymer composites. In this context, this paper gives a detailed review and discussion of the following: (i) the machinability of CFRP including chip removal mechanisms, cutting force, tool wear, surface roughness, delamination and the characteristics of uncut fibres; (ii) cutting tool requirements for CFRP machining; and (iii) recent industrial solutions: advanced edge geometries of cutting tools, coatings and technologies. In conclusion, it can be stated that advanced geometry cutting tools are often necessary in order to effectively and appropriately machine required quality features when working with CFRP composites.

Advanced cutting tools and technologies for drilling carbon fibre reinforced polymer (CFRP) composites: A review

For the past three decades, robotic machining has attracted a large amount of research interest owning to the benefit of cost efficiency, high flexibility and multi-functionality of industrial robot. Covering articles published on the subjects of robotic machining in the past 30 years or so; this paper aims to provide an up-to-date review of robotic machining research works, a critical analysis of publications that publish the research works, and an understanding of the future directions in the field. The research works are organised into two operation categories, low material removal rate (MRR) and high MRR, according their machining properties, and the research topics are reviewed and highlighted separately. Then, a set of statistical analysis is carried out in terms of published years and countries. Towards an applicable robotic machining, the future trends and key research points are identified at the end of this paper.

/pdf/industrial-robotic-machining-a-review-22ic1kzvyl.pdf

Industrial robotic machining: a review

Industrial robots have been used in machining applications for their advantages such as their high flexibility and low cost. However, the relatively low stiffness of the robot can seriously affect its positioning accuracy and its machining quality. In this paper, a posture optimization method is presented, aiming at increasing the stiffness of the robot in machining applications. First, a performance index is proposed to evaluate the stiffness of the robot with a given posture after an in-depth study of the relationship between the translational displacement of the robot end effector and the force applied on it. The index is then demonstrated to be a frame invariant. By maximizing the index, a robot posture optimization model is further established and solved by a novel solution method based on the Jacobian matrix. Finally, experimental results achieved on a KUKA KR360-2 robot verify the correctness of the stiffness performance index, and the application of the posture optimization method in a robotic drilling system shows its effectiveness. We propose a performance index to evaluate the stiffness of a robot at a given posture.The performance index is demonstrated to be a frame invariant.We establish a robot posture optimization model by maximizing the performance index.The posture optimization model is solved by a novel method based on the Jacobian matrix.

Stiffness-oriented posture optimization in robotic machining applications

Off-line programming systems are essential tools for the effective use of robots in the manufacturing environment. This paper presents a dedicated off-line programming system for robotic drilling in aerospace manufacturing. Following a brief introduction of the system architecture, the paper discusses two major problems of off-line programming for robotic drilling, i.e., redundancy resolution and position correction. A new performance index is proposed for the combined requirements of singularity and joint-limit avoidance, followed by a discussion of the redundancy resolution scheme by using numerical optimization at the joint displacement level. A position correction method using measurement data of reference holes is developed for the enhancement of robotic drilling accuracy. Robot programs generated by using the developed system have been tested on a robotic drilling system, and the experimental results are provided.

An off-line programming system for robotic drilling in aerospace manufacturing

A three-dimensional (3D) micromechanical finite element (FE) model of machining of fiber-reinforced polymer (FRP) composites was developed in the paper. The FE modeling considers the three phases of a composite, in which the interphase between the fiber and matrix can realize interfacial debonding to represent the failure of composites and allow heat transfer. The machined surface observations and surface roughness measurements of carbon fiber-reinforced polymer (CFRP) composites at different fiber orientations were done firstly, and then, the model predictions of the machining responses, such as cutting force, temperature, and surface roughness, at different fiber orientations were compared with various experimental data for model validation. It is indicated that the three-phase micromechanical model is capable of precisely predicting machining responses and describing the failure modes of fiber shearing or bending related with fiber orientations in the chip formation process. To investigate the complex coupling influences of multiple machining parameters on the key responses of CFRP composites, the single-factor analyses of each machining parameter were first carried out, and then, the multi-factorial analysis of multiple machining parameters was performed based on the orthogonal design of experiment and the analysis of variance (ANOVA) to quantitatively compare the influences of these key machining parameters on the cutting force and surface roughness. It was found that the fiber orientation angle, depth of cut, and cutting speed prove to be the important factors affecting the cutting force and surface roughness and that the coupling effects of these machining parameters all are relatively negligible in the machining of CFRP composites.

Factor analysis of machining parameters of fiber-reinforced polymer composites based on finite element simulation with experimental investigation

A novel 6-degree of freedom (DOF) posture alignment system, based on 3-DOF positioners, is presented for the assembly of aircraft wings. Each positioner is connected with the wing through a rotational and adsorptive half-ball shaped end-effector, and the positioners together with the wing are considered as a 3-PPPS (P denotes a prismatic joint and S denotes a spherical joint) redundantly actuated parallel mechanism. The kinematic model of this system is established and a trajectory planning method is introduced. A complete analysis of inverse dynamics is carried out with the Newton-Euler algorithm, which is used to find the desired actuating torque in the design and path planning phase. Simulation analysis of the displacement and actuating torque of each joint of the positioners based on inverse kinematics and dynamics is conducted, and the results show that the system is feasible for the posture alignment of aircraft wings.

A novel posture alignment system for aircraft wing assembly

Autoclave process is widely used in manufacturing processes for thermosetting matrix composite materials. During the process, the non-uniformity of temperature distribution in autoclave may result ...

Yinglin Ke

Papers

Stiffness-oriented posture optimization in robotic machining applications

An off-line programming system for robotic drilling in aerospace manufacturing

Factor analysis of machining parameters of fiber-reinforced polymer composites based on finite element simulation with experimental investigation

A novel posture alignment system for aircraft wing assembly

Design optimization of molds for autoclave process of composite manufacturing