Fangyu Peng

• Huazhong University of Science and Technology

Robot teleoperation plays an important role in industrial manufacturing in unknown and dangerous environments beyond human reach. In telerobotic manufacturing tasks, environmental interaction forces may vary significantly from task to task. Therefore, it is crucial to provide operators with the specific proportional feedback of environmental intera...

Accurate regression prediction is a critical objective in industry; however, epistemic and aleatoric uncertainties can significantly impact prediction accuracy. Existing research primarily focuses on either prediction or uncertainty estimation, with limited studies addressing joint prediction methods and accuracy enhancement. This paper proposes an...

Robot skill learning and generalization in robotic polishing tasks play a pivotal role in efficient task planning, particularly in tasks where visual scanning is not convenient. Compared to other manipulations, skill learning of robot polishing trajectories and skill generalization between similar trajectories require high accuracy, and skill learn...

In 3D printing of critical structural components made from continuous carbon fiber-reinforced composites (CCFRC), mechanical performance and manufacturing efficiency are mutually constrained. This paper introduces a novel closed-loop iterative optimization method that swiftly identifies the optimal balance between performance and efficiency for the...

This paper propose a random fiber distribution generation algorithm based on lattice partition, which addresses the issue of limited increase in fiber volume fraction caused by the random movement of fibers in previous methods. By partitioning the representative volume element (RVE) window into lattices and moving fibers directionally, the proposed...

In recent years, robotic machining has become one of the most important paradigms for the machining of large and complex parts due to the advantages of large workspaces and flexible configurations. However, different configurations will correspond to very different system performances, influenced by the position-dependent properties. Therefore, the...

Bilateral teleoperation with force feedback allows the operators to apply their skills to accomplish challenging tasks safely. Most teleoperation bilateral systems are designed for single interaction scenarios and low-frequency force feedback, which limits their overall performance in complex interaction tasks. Furthermore, the use of passive contr...

Error prediction and compensation are crucial requirements for improving robot accuracy. To this end, this paper introduces an advanced online method that integrates error-motion correlation for the precise prediction and compensation of robot position errors. The proposed method includes feature selection, model interpretability design, and compen...

Due to their inherent characteristics, robots inevitably suffer from pose errors, and accurate prediction is the key to error compensation, which facilitates the application of robots in high-precision scenarios. Existing studies almost follow the points-view, and the compensation effect depends entirely on the accuracy of the point prediction, whi...

Chatter is a common state in milling and turning, which will reduce the machining quality of parts. For taking adequate measures to avoid chatter, chatter detection is necessary. However, chatter recognition still has many difficulties for both turning and milling. Due to the material removal effect, the chatter frequency will change. The existing...

Robots are widely employed in industrial settings owing to their efficiency, flexibility, and extensive operational ranges. However, their application in high-precision scenarios is limited owing to their low absolute accuracies. Existing methods suffer from high measurement costs, and limited applicability and accuracy. To address these issues, an...

Low-frequency chatter severely limits robotic milling efficiency. In this paper, tuned mass dampers (TMDs) are introduced to suppress low-frequency chatter based on robotic modal directionality. A TMD model with mounting angle is established, and the suppression effect of TMD on the robotic low-frequency dynamic compliance with different mounting d...

The structural vibration caused by poor rigidity is one of the main obstacles limiting the machining efficiency of robot milling. The existing vibration suppression strategies mainly focus on process parameter optimization, passive vibration absorption at the end and feedback control of joint motor. Although these strategies have certain vibration...

While industrial robots are widely used in various fields owing to their large workspace and high flexibility, significant errors constrain their application in high-precision scenarios. Though there have been notable achievements in mechanism modeling for different working conditions, they are complex, work-dependent, and difficult to apply conven...

The foundation of high-precision 3D reconstruction is the acquisition of high-precision point clouds. Through multi-view point cloud scanning and alignment, the point cloud of parts can be obtained. The great flexibility of the robot enables it to carry out scanning operations that require multi-view. However, the robots are limited in position err...

Chatter is a critical factor that impacts both the efficiency and quality of the milling, and the process damping can suppress its occurrence. Process damping is caused by the interference between the machined surface and the flank face of the tool, which is manifested as an effect on the damping term of the system. In this paper, a method of apply...

To achieve a stable interaction between the robot and the environment, stable force control of the robot is required. In this paper, a position-based impedance adaptive controller is proposed. The proposed method tracks the expected contact force based on estimating the parameters of the environment. Within this framework, we analyze environmental...

Robotic machining efficiency and accuracy are constrained by milling vibrations and chatter. The dynamic characteristics of robots are highly influenced by their poses. Consequently, it is crucial to obtain the robot’s dynamic characteristics in any given pose to mitigate vibrations and prevent chatter during large-range machining. This paper propo...

TiBw/TA15 composites are featured by the network-structured distribution of the reinforced phase quasi-continuously. The multiphase microstructure including the TiB ceramic whisker reinforcement, the titanium alloy matrix and the interface plays a significant role in cutting processes. In this paper, multiscale finite element (FE) cutting models in...

Uneven distribution of machining-induced residual stress (MIRS) caused by dynamic cutting conditions and material internal properties has significant impact on fatigue resistance, stress corrosion resistance and accuracy retention of aerospace structural parts. Owing to the challenges in describing residual stress distribution property, this paper...

Thin-walled parts such as blades are widely used in aerospace field, and their machining quality directly affects the service performance of core components. Due to obvious time-varying nonlinear effect and complex machining system, it is a great challenge to realize accurate and fast prediction of machining errors of such parts. To solve the above...

Robot milling has become an important means of machining large structural parts, and the dynamic compliance of robot end is the key factor affecting machining quality and efficiency. The dynamic characteristics of the milling robot end are different in movement state and static state and have significant pose dependence. In order to effectively eva...

The existing studies on milling robot dynamic characteristics pay little attention to robot structures, while structure mode shape analysis is significant to accurate vibration control. This paper applies the 3D scanning laser Doppler vibrometer to the milling robot, and proposes the R²-based compliance identification criterion to identify the robo...

There is a gap that should be filled in a deeper understanding of the potential role played by multiple microstructures in the material mechanical properties during the machining of network-structured TiBw/TA15 composites. In view of this, a comprehensive constitutive model is established coupled with the shear lag theory and Weibull distribution f...

Chatter is a key problem that restricts the quality and efficiency of robotic milling, and the modal characterization of the robotic milling system is an important factor that affects the chatter. Doppler vibration measurement experiment shows that the vibration mode of the robotic milling system changes significantly with different modal frequenci...

With the rapid advancement of manufacturing in China, robot machining technology has become a popular research subject. An increasing number of robots are currently being used to perform complex tasks during manual operation, e.g., the grinding of large components using multi-robot systems and robot teleoperation in dangerous environments, and mach...

With the development of deep transfer learning, the generalization abilities of models in similar scenarios have been significantly improved. However, for regression tasks, either the marginal distribution or the conditional distribution is usually ignored. In addition, initiative regarding the representation and learning of domain knowledge is lac...

The machining quality of a part is one of the most important factors affecting work effectiveness and service time, and it is closely related to multi-stage manufacturing processes (MMPs). State space model (SSM) is a typical method to analyze error propagation in MMPs, which contains the deep laws of error propagation, but the modeling process is...

Regenerative chatter is an important factor affecting the efficiency and quality of robot milling of large and complex curved parts, especially when the weak rigid posture is forced to be selected under geometric interference. And the regenerative chatter in robotic milling is not only related to the tool-spindle mode but also affected by the tool...

Industrial robots play an important role in the milling of large complex parts. However, the robot is less rigid and prone to vibration-related problems; chatter, which affects machining quality and efficiency, is more complex and difficult to monitor. In this paper, a variational mode decomposition-support vector machine (VMD-SVM) model based on i...

Inconel 718, a nickel-based superalloy, is widely used in the key parts of aero-engine owing to its high performance at elevated temperatures. Meanwhile, Inconel 718 is a typical difficult-to-cut material which is hard to obtain ideal surface integrity by conventional machining (CM). Laser-assisted machining (LAM) has a good potential to improve th...

Currently, it still lacks the controlled studies which compare differences in the machinability between the TA15 alloy and network-structured TiBw/TA15 composites, which is not conducive to promoting the design and practical application of the TiBw/TA15 composites. Therefore, in this paper, the impact of material properties on the micro-cutting per...

Thin-walled structural parts, such as aeroengine casings, impellers, blades, and disks, are widely used in the aerospace industry due to their outstanding performance. A more efficient and accurate prediction approach for machining distortion has also been widely considered. The traditional finite element analysis approach, which is commonly used i...

Industrial robot's advantages in flexibility and workspace make them used increasingly in multi-axis milling process. However, because of their posture-dependent mechanical and kinematic performance, the quality of the trajectory affects the milling precision directly. Therefore, a virtual repulsive potential field (VRPF) algorithm of posture traje...

With the increasing demand for higher quality and performance of equipment and assembly in aerospace, shipbuilding, medical and other fields, the machining accuracy of parts is facing higher requirements. It is particularly important to predict the cutting force accurately, which is the main physical quantity in the machining process and basis of p...

With the changes in joint torque and driving state caused by robot postures, the stiffness properties behave differently. However, constant joint stiffness parameters cannot accurately reflect the deformation of different robot postures. To solve this problem, based on the hypothesis of flexible joints, this paper proposes a pose-dependent identifi...

Within the finite element simulation model of metal manufacturing processes, the setting of physical properties of the materials will significantly affect the final simulation results. In this paper, a hybrid approach to integrate mechanical models and experimental data is proposed to identify the constitutive parameters and tool-chip friction coef...

Five-axis milling is an important machining method for complex surface parts, and chatter is an important factor affecting its machining efficiency and quality. Stability boundary prediction can effectively optimize process parameters and avoid chattering, but it is difficult to actively improve the stability boundary. Therefore, in this paper, a r...

TiBw/TA15 composites with network architecture is a new class of metal matrix composites with superior mechanical properties. It has great potential to be applied in the aerospace and automotive fields. However, it is still a challenge to obtain the good surface quality in micro-machining of this kind of composite material. Compared with the micro-...

Industrial robots are widely applied in manufacture industry recently because of their great flexibility and large working space. Due to the posture-dependent stiffness of industrial robots, a force-induced error index (FEI), which simultaneously takes milling force and robot tool end stiffness in consideration, is proposed to describe the error de...

The TiBw/TA15 composites with network architecture have potential applications in the aerospace and automobile industry. In this paper, the in-situ high-speed imaging of the cutting zone at the micro-scale and digital image correlation analysis of the image sequences were conducted. And the qualitative analysis of chip characteristics was performed...

With the increasing demand for higher quality and performance of equipment and assembly in aerospace, shipbuilding, medical and other fields, the machining accuracy of parts is facing higher requirements. It is particularly important to predict the cutting force accurately, which is the main physical quantity in the machining process and basis of p...

There are common features such as the tool path curvature and torsion, and cutter-orientation change in sculptured surface machining, which bring new challenges to the accurate prediction of cutting force. Aiming at the tool path curvature and torsion, and cutter-orientation change, a cutting force prediction method based on the screw theory is pro...

AerMet100 steel is a typical difficult-to-cut material, and laser-assisted milling (LAM) is a promising machining technology for this kind of material. In LAM process, the material is softened by the thermal effect of laser beam, which improves the machinability of the materials. And finally, the cutting forces are reduced compared with conventiona...

In aviation and navigation, complicated parts are milled with high-speed low-feed-per-tooth milling to decrease tool vibration for high quality. Because the nonlinearity of the cutting force coefficient (CFC) is more evident with the relatively smaller instantaneous uncut chip thickness, the stable critical cutting depth and its distribution agains...

SiCp/Al composites are extremely difficult to process due to excessive tool wear and poor surface integrity. This paper presents a novel material processing method combining laser surface melting modification and precision milling to improve the machinability and surface performance of this material. The surface layer laser modification experiments...

Due to the advantages of large workspace, low cost and the integrated vision/force sensing, robotic milling has become an important way for machining of complex parts. In recent years, many scholars have studied the problems existing in the applications of robotic milling, and lots of results have been made in the dynamics, pose planning, deformati...

Thin-walled structural parts are widely used in aerospace industry, the prediction of machining errors of these parts has attracted more and more attention over the past decades. Due to the complicated time-varying nonlinear characteristics and the lack of experimental data, it is difficult to use the mechanism model or data-driven model to predict...

During the robotic milling process, vibration is one of the main factors that affect the machining accuracy and surface quality due to the low stiffness of the robot structure. The robotic milling stability is a function of the frequency response function (FRF) at the tool tip, which is posture-dependent within the workspace. This paper introduces...

Compared with conventional milling, laser-assisted milling (LAM) enhances the productivity of difficult-to-cut materials and is a green process due to the elimination of coolant. However, this heat-assisted process may induce a detrimental heat-affected zone (HAZ, generally referred to as phase transformation zone) in the workpiece. This paper pres...

Complex aerospace parts with difficult-to-cut materials AerMet100 etc. should be processed by five-axis milling at low spindle speed, in which the process damping cannot be ignored in stability analysis. Based on the established nonlinear process damping and relevant equivalent process damping coefficient model, a 3D stability lobe diagram (SLD) co...

In this paper, an analytical model for estimating the micro-ball-end milling forces is presented based on experimental investigation of progressive tool flank wear. The wear form and wear mechanism of the micro-ball-end mill are revealed through a series of micro-ball-end milling experiments. The effecting laws of cutting parameters such as feed pe...

The natural frequencies and damping ratios of machine tool structure vary with the change of the machining position in the machining space. When the stiffness distribution of the whole machine structure is not uniform, some position change will further lead to the change of weak components of the structure. In order to detail the position-dependent...

In the machining of complicated surfaces, the cutters with large length/diameter ratios are used widely and the deformation of the machining system is one of the principal error sources. During the process planning stage, the cutting direction angle, the cutter lead and tilt angles are usually optimized to minimize the force induced error. It may l...

Laser-assisted milling (LAM) represents an innovative process to enhance productivity in comparison with conventional milling. The workpiece temperature in LAM not only affects the cutting performance of materials, but also the machined surface quality of the part. This paper presents a 3D transient finite element (FE) model for workpiece temperatu...

Cutting edge of miniature ball-end mill is one of decisive importance for the machining performance by affecting the thermal and mechanical load in cutting process. In this paper, a semi-analytic model is proposed to estimate the cutting forces in micro ball-end milling of NAK80 steel considering wear-varying cutting edge and the associated nonline...

Vibration characteristics of cutting vary with the change of the cutting excitation and the change of structure dynamics. To analysis and reduce the vibration, this paper presents a method of identifying the principal mode of vibration to analysis the coupling effect of cutting excitation and position-dependent structure dynamics on cutting vibrati...

Multi-axis milling (especially five-axis) is in the ascendant for high precision manufacturing of a product with a sculptured surface such as ship propeller, owing to its multi-axis linkage and resulting outstanding superiorities. Needs of a faster-improving manufacturing level of sculptured surface milling are derived by higher performance require...

The specific cutting energy can characterize the machinability of the cutter for a material, and its change is a reflection of the size effect in the metal cutting process. It is critical to study the cutting process using an energy-based processing signature method with the purpose of improving the machining performance. In this paper, a specific...

This paper presents a more efficient ultra-precision diamond fly-cutting method to achieve the damage-free surface machining of hard-brittle zirco-nia ceramics at one time instead of the traditional abrasive-based processes. Firstly, the smoothed particle hydrodynamics (SPH) cutting simulation model of zirconia ceramics is established in LS-DYNA ba...

Five-axis milling has becoming more popular and widely used in various fields recently, such as aerospace, aviation, shipbuilding, and so on, owing to its capacity to realize higher precision and efficiency. However, the cutter-workpiece engagement (CWE) determination and cutting force prediction in five-axis milling become complicated and remain a...