Liping Chen

Huazhong University of Science and Technology | hust

Iterative learning control (ILC) is a popular scheme in the trajectory tracking of manipulators, greatly improving tracking accuracy despite often requiring multiple iterations over identical trajectories. This research introduces an optimization technique for ILC parameters, enhanced with proportional-derivative (PD) feedback control, which aims t...

Physics-informed neural networks (PINNs) have garnered widespread use for solving a variety of complex partial differential equations (PDEs). Nevertheless, when addressing certain specific problem types, traditional sampling algorithms still reveal deficiencies in efficiency and precision. In response, this paper builds upon the progress of adaptiv...

Robotic manipulators play a pivotal role in modern intelligent manufacturing and unmanned production systems, often tasked with executing specific paths accurately. However, the input of the robotic manipulators is trajectory which is a path with time information. The resulting core technology is trajectory planning methods which are broadly classi...

The positioning and velocity accuracy of spraying robots determine the quality of the coating, and the influence of the robotic dynamic characteristics on control precision is significant. This paper presents a method of linearizing dynamic characteristics into feedforward coefficients and designs a dual-loop control system consisting of an inner v...

The artificial potential field method is a highly popular obstacle avoidance algorithm which is widely used in the field of industrial robotics due to its high efficiency. However, the traditional artificial potential field method has poor real-time performance, making it less suitable for modern factory work patterns, and it is difficult to handle...

The new generation of low-earth-orbit (LEO) satellite constellation systems has the characteristics of low delay, strong signal and global coverage, and it is an important direction for the development of next-generation communication technology. A major disadvantage is that the constellation system is huge, often composed of hundreds or thousands...

The trajectory planning method with dynamics is the key to improving the motion performance of manipulators. The optimal control method (OCM) is a key technology to solve optimal problems with dynamics. There are direct and indirect methods in OCM; indirect methods are difficult to apply to engineering applications, and so direct methods are widely...

With the development of information and communication technology and the advent of the Internet of Things (IoT) era, cyber-physical system (CPS) is becoming the trend of products or systems. The deep integration and real-time interaction between the physical world and the virtual world expand system functions. Although there are some CPS implementa...

Structural analysis is a method for verifying equation-oriented models in the design of industrial systems. Existing structural analysis methods need flattening of the hierarchical models into an equation system for analysis. However, the large-scale equations in complex models make structural analysis difficult. Aimed to address the issue, this st...

Structural analysis is a method for verifying equation-oriented models in the design of industrial systems. Existing structural analysis methods need flattening the hierarchical models into an equation system for analysis. However, the large-scale equations in complex models make the structural analysis difficult. Aimed to address the issue, this s...

Computed Torque Control (CTC) is the most direct and effective way to improve the motion control performance of robot. But the computation of the joint torque is quite difficult, and because of the uncertainty of the parameters, an accurate inverse robot dynamic model for torque generation is difficult to obtain. An efficient inverse dynamic model...

The ever-increasing functional density and complexity of the satellite systems, the harsh space flight environment, as well as the cost reduction measures that require less operator involvement are increasingly driving the need to develop new approaches for fault diagnosis and health monitoring (FD-HM). The data-driven FD-HM approaches use signal p...

An accurate dynamic model for the computer numerical control machine tool feed system is of great significance to improve the machining accuracy. However, the accurate dynamic model of the feed system is difficult to be established because its dynamic characteristics not only depend on the performance of subsystems, such as mechanical, electrical,...

High fidelity models of feed drive are critical factors to increase positioning accuracy and decrease contour error. To predict feed drives dynamics, this paper reports a novel method for modeling dynamics of feed drive by combining advantages of theoretical derivations and deep learning. First, the paper derives a rigid-flexible-combined dynamics...

Position error-compensation control in the servo system of computerized numerical control (CNC) machine tools relies on accurate prediction of dynamic tracking errors of the machine tool feed system. In this paper, in order to accurately predict dynamic tracking errors, a hybrid modeling method is proposed and a dynamic model of the ball screw feed...

Cyber-physical system (CPS) is a new trend in the complex system related research works, where network connectivity enhances computing power and systemic behavior emerges through the competition, interaction, collaboration and integration among individual interweaving, which consists of real-time monitoring, data management, physical feedback contr...

In order to improve the fault isolability properties of a diagnosis system, a usual way is to add sensors for measuring extra state variables. Unlike previous literatures that usually focus on adding new sensors to fulfill diagnosis specifications, this paper aims to analyze the influences on the isolability properties when more variables are measu...

A new approach is proposed for isolating faults and fast identifying the redundant sensors of a system in this paper. By introducing fault signal as additional state variable, an augmented system model is constructed by the original system model, fault signals and sensor measurement equations. The structural properties of an augmented system model...

This paper studies the problem of efficiently scheduling dependent computational tasks on heterogeneous computing systems. Computational tasks with precedence constraints are commonly represented by a directed acyclic graph (DAG). Four commonly used algorithms including a cellular genetic algorithm (CGA) are performed for scheduling a special type...

In many engineering optimization problems, the objective and the constraints which come from complex analytical models are often black-box functions with extensive computational effort. In this case, it is necessary for optimization process to use sampling data to fit surrogate models so as to reduce the number of objective and constraint evaluatio...

A structural decomposition method based on symbol operation for solving differential algebraic equations (DAEs) is developed. Constrained dynamical systems are represented in terms of DAEs. State-space methods are universal for solving DAEs in general forms, but for complex systems with multiple degrees-of-freedom, these methods will become difficu...

Reciprocal screw theory is used to recognize the kinematic joints of assemblies restricted by arbitrary combinations of geometry constraints. Kinematic analysis is common for reaching a satisfactory design. If a machine is large and the incidence of redesign frequent is high, then it becomes imperative to have fast analysis-redesign-reanalysis cycl...

This paper presents the multi-objective optimization problem of double suction centrifugal pump using Kriging meta-model. A set of double suction centrifugal pumps with various blade shapes were numerically simulated in the CFD software. Efficiency η and required net positive suction head (NPSHr) were investigated through these numerical simulation...

Three-dimensional B-rep is often used to convey product models in computer-aided design, computer-aided engineering, computer-aided process planning, and computer-aided manufacturing systems. Meaningful shape features need to be recognized from the B-rep models for product re-design and manufacturing. In this article, a novel hint-based reusable sh...

Optimization design of centrifugal pump is a typical multiobjective optimization (MOO) problem. This paper presents an MOO design of centrifugal pump with five decision variables and three objective functions, and a set of centrifugal pumps with various impeller shroud shapes are studied by CFD numerical simulations. The important performance index...

3D shape matching is widely used in engineering design for model retrieval, shape similarity assessment or collaborative development. In this paper, an enhanced graph representation and heuristic tabu search based approach is presented to enable flexible and efficient 3D shape matching. The core idea includes (1) generic shape features are recogniz...

As the maximum speed for processors seems to have reached its peak, parallelization becomes an important way to speed up the simulation. This paper discusses the problems of parallelizing the task graphs that represent the system-level physical models at the equation level. The methods for estimating the runtimes of the equation solving tasks are p...

This paper presents the optimization of vibrations of centrifugal pump considering fluid-structure interaction (FSI). A set of centrifugal pumps with various blade shapes were studied using FSI method, in order to investigate the transient vibration performance. The Kriging model, based on the results of the FSI simulations, was established to appr...

This study proposes a new uncertain analysis method for multibody dynamics of mechanical systems based on Chebyshev inclusion functions The interval model accounts for the uncertainties in multibody mechanical systems comprising uncertain-but-bounded parameters, which only requires lower and upper bounds of uncertain parameters, without having to k...

For modeling and simulation of distillation process, there are lots of special purpose simulators along with their model libraries, such as Aspen Plus and HYSYS. However, the models in these tools lack of flexibility and are not open to the end-user. Models developed in one tool can not be conveniently used in others because of the barriers among t...

This paper proposes a new interval analysis method for the dynamic response of nonlinear systems with uncertain-but-bounded parameters using Chebyshev polynomial series. Interval model can be used to describe nonlinear dynamic systems under uncertainty with low-order Taylor series expansions. However, the Taylor series-based interval method can onl...

In this article, we present a set of novel techniques, which include (1) sensor-stage calibration, (2) high-level script programming for the flexible control of data sensing, and (3) a framework for dynamic data sensing, visualization and shape modeling. It enables the integration of multiple three-dimensional sensors into one controlled three-dime...

Some 3D complex shapes such as stair and compound-hole in engineering design always contains various geometric face types, adjacent geometric constraints and typical design semantics. These 3D shapes can be defined as template design features because they are frequently reused for synchronous shape modeling to greatly accelerate design and analysis...

Current design feature recognition mainly depends on the connective attributes of edges or faces in the CAD models, such as convexity, concavity, and tangency. However, it is difficult to uniquely define the mixed connective attributes of the generic features in some cases. A novel generic design feature recognition approach by detecting the hint o...

Modelica is designed to describe hybrid complex physical system in form of differential algebraic equations (DAEs), which usually consisting of scalar equations and array equations. General method of reduction and decomposition of modelica model can only dealing with scalar equations, which means arrays must be flattened to scalars completely, that...

A hierarchical optimization procedure for the optimal synthesis of a double-axle steering mechanism used in truck with dynamic loads is presented. A multibody model of double-axle steering mechanism is presented to characterize the leaf spring effect. The influences of dynamic loads, the motion interference of steering linkage resulted from the ela...

Design sensitivity analysis of flexible multibody systems is important in optimizing the performance of mechanical systems. The choice of coordinates to describe the motion of multibody systems has a great influence on the efficiency and accuracy of both the dynamic and sensitivity analysis. In the flexible multibody system dynamics, both the float...

To solve the dynamic response problem that contains uncertain parameters, the uncertain differential equations need to be calculated. In this study, a new efficient numerical interval method for uncertain differential equations is presented. The interval dynamic analysis of a Two-Degree-of-Freedom (2DOF) bicycle car model with uncertain parameters...

A fuzzy adaptive sliding mode controller for an air spring active suspension system is developed. Due to nonlinearity, preload-dependent spring force and parameter uncertainty in the air spring, it is difficult to control the suspension system. To achieve the desired performance, a fuzzy adaptive sliding mode controller (FASMC) is designed to impro...

Air brake system has been widely used in heavy trucks and intercity buses for its great superiori-ty over other brake system. The practical per-formance of air brake system may be greatly dif-ferent from if we analyze it with static theory. Thus, it is necessary to build an integrate air brake system model to simulate the process of brake accuratel...

This paper presents a detailed AMT model com-posed of various components from multi-domains like mechanical systems (clutch, gear pair, synchro-nizer, etc.), pneumatic actuator systems (clutch actu-ation system, gear select actuation system, gear shift actuation system, etc.). The model is implemented using the Modelica modeling language in an obje...

This paper shows the modeling and simulation of fuel economy and vehicle dynamics of a heavy truck with Modelica. The work was carried out on MWorks, which is developed by Huazhong Univer-sity of Science & Technology. Comparisons be-tween measured data and simulation results va-lidate the correctness of the model, and demon-strate that Modelica can...

The purpose of shock absorbers are to dissipate im-pact energy, and control tire force variation, the shock absorber has great influence on both ride and handling performance of vehicles, and a great many previous researches have been done on modeling and simulation of the shock absorber. In this paper, a de-tailed model of shock absorber is establ...

The automatic mechanical transmission (AMT) was designed by automobile manufacturers to provide a better driving experience, especially in cities where congestion frequently causes stop-and-go traffic patterns. It uses electronic sensors, processors, hydraulic or pneumatic actuators execute clutch actuation and gear shifts on the command of the dri...

Hydraulic power steering systems, which can provide large steering assist force, are widely used for heavy-duty commercial vehicles to enhance the driving comfort. Such systems have great influences on vehicle controllability, steering stability and safety. However, interpolated table from experiment data was used as the assist force to study the v...

In this paper, we propose an Adaptive Moving Least-Squares (AMLS) surface based approach for multi-view or multi-sensor point cloud ICP registration. The core idea of this approach is to reconstruct a smooth and accurate surface, e. s. AMLS surface, from a point cloud, without data segmentation and surface model selection, resulting in an accurate...

This paper starts with a classical mechanism synthesis problem and focuses on the concept design and dynamics analysis of an independent suspension that has invariable orientation parameters when the wheel moves up (jounces) and down (rebounds). The paper first proposes a symmetric redundant constraint suspension structure that has invariable orien...

Elastomeric bushings are widely used in the passenger cars to make the cars have an ideal vehicle Noise, Vibration and Harshness (NVH) performance. However, elastomeric bushings also influence on the vehicle handling, ride and the durability performance of each component in the vehicle suspension system. It is relatively easy and cost effective to...

Modeling of clearance joints plays an important role in the analysis and design of multibody mechanical systems. Based on the absolute nodal coordinate formulation (ANCF), a new computational methodology for modeling and analysis of planar flexible multibody systems with clearance and lubricated revolute joints is presented. A planar absolute nodal...

Heat exchanger is widely used in the vehicle cooling system and its performance influences the vehicle dynamic performance significantly. In present paper, an object-oriented louver fin-and-tube heat exchanger model was developed to simulate the dynamic outlet temperature of air and coolant. A two-dimensional discrete strategy, which divided the he...

To solve the dynamic response problem that contains uncertain parameters needs, the stochastic differential equations needs to be calculated. Interval analysis has been widely used to solve engineering problems which contain many uncertain parameters usually. But the numerical solution method for stochastic differential equations based on the inter...

Hydraulic power steering system, which can reduce the steering hand force by applying the output from a hydraulic actuator, has been widely used in vehicles. In this paper, a detailed steer model including steering column, steering trapezium, and detailed hydraulic power steering system which is consisting of steering cylinder, relief valve, rotary...

Hydraulic systems are popular on vehicles, such as power steering, shock absorbers, brakes, etc. Many previously works have been done on the modeling and simulation of the hydraulic systems. However, these models and parameters are usually established on the basis of plans, drawings, measurements, observations, experiences, expert knowledge and sta...

A modified directed graph method is proposed to solve hybrid geometric constraint systems including 3D geometric constraints and assembly constraints derived from integrated variational design. Firstly, several basic constraints are defined to describe diverse geometric constraints, and two abstract dual objects are used to encapsulate various geom...

Hydro-pneumatic suspension and multi-bridges steering system, which can meet the demands of ride comfort and steering maneuverability of the crane by their excellent nonlinear stiffness and damping characteristics and innovative control technology in their electro-hydraulic rear axle steering system, is used for construction industry vehicles widel...

With the strategy “Automatically Reduce Natural-Coordinate DAEs Assembled Automatically” in mind, the authors have developed a new reduction method on natural-coordinate constant constraint (NCCC). A NCCC constrains a state variable to a constant, leading to a simplest constraint equation which often appears in the joints which connect elements def...

Based on the absolute nodal coordinate method, the large deformation flexible multibody system with nonlinear constraints was investigated. The equations of motion were deducted by Augmented Lagrangian method. The primary unknowns in the equations of motion are independent of the constraint equations. Only taking the generalized positions as the pr...

In this paper, we present a 3D geometric constraint solver for direct manipulation of B-rep model. First, we discuss the representation of 3D geometric elements and geometric constraints. Then, we propose two abstract dual objects to encapsulate diverse geometric elements based on the decoupled property analysis of constraint configuration. Subsequ...

This article presents an alternative topology optimization method for the design of compliant actuators using mesh-free methods, in which the thermo-mechanical multi-physics modelling and geometrically non-linear analysis are included. The relatively new mesh-free method rather than the standard finite element method (FEM) is used to discretize the...

A new modeling and simulation methodology for a pneumatic brake system with ABS widely used in commercial vehicle is presented. The main parts of the pneumatic brake system such as air storage reservoir, tandem dual circuit brake valve, relay valve, ABS air regulating valve and diaphragm brake chamber are included and modeled by an object oriented...

Clutch actuation systems are complex systems where hydraulic, pneumatic, mechanical and electrical components are coupled. Such systems have grate influence on vehicle performance. This paper presents a detailed clutch actuation model composed of components from multi-domains like mechanical and pneumatic actuation system, hydraulic boosting system...

A computational methodology for analysis of spatial flexible multibody systems, considering the effects of the clearances and lubrication in the system spherical joints, is presented. The dry contact forces are evaluated through a Hertzian-based contact law, which includes a damping term representing the energy dissipation. The frictional forces ar...

The air brake system has been widely used since its great superiority over many other kinds of brake systems, but the capacity and the stability of air brake system are determined by many factors which are always uncertain and difficult to be evaluated accurately. So it is necessary to improve the robustness of this kind of brake system. In this pa...

This paper employs a new finite element formulation for dynamics analysis of a viscoelastic flexible multibody system. The viscoelastic constitutive equation used to describe the behavior of the system is a three-parameter fractional derivative model. Based on continuum mechanics, the three-parameter fractional derivative model is modified and the...

A new dynamic modelling technique for a two-link flexible manipulator based on the absolute nodal coordinate method is firstly investigated. The manipulator flexible links are discretized by ID beam elements based on the absolute nodal formulation, and the shear deformations are neglected. The equations of motion with constant system mass matrix fo...

The compression of CAD models is a key technology for realizing Internet-based collaborative product development because big model sizes often prohibit us to achieve a rapid product information transmission. Although there exist some algorithms for compressing discrete CAD models, original precise CAD models are focused on in this paper. Here, the...

In density-based topology optimization, 0/1 solutions are sought. Discrete topological problems are often relaxed with continuous design variables so that they can be solved using continuous mathematical programming. Although the relaxed methods are practical, grey areas appear in the optimum topologies. SIMP (Solid Isotropic Microstructures with P...

The viscoelastic damping is one of key factors that affect vehicle vibration. It has been demonstrated that fractional derivative model can accurately model this kind of frequency dependence damping very well. Generally, the excitation of rough road can be acted as a stationary random vibration process in time domain when a vehicle is traveling at...

Purpose – The purpose of this paper is to introduce a new method to carry out the design optimization of the tool head system in the heavy-duty machine tool where closed hydrostatic guideways with multiple pockets are employed. Design/methodology/approach – A more accurate method of pressure calculation for closed hydrostatic guideways is introduce...

A nonlinear control system that integrated active front steering system and vehicle dynamics control system based on a multi-body vehicle dynamic model is introduced in this paper. The multibody vehicle dynamic model based on ADAMS can accurately predict the dynamics performance of the vehicle. The control strategy consists of two control objective...

This paper proposes a new level set method for structural shape and topology optimization using a semi-implicit scheme. Structural boundary is represented implicitly as the zero level set of a higher-dimensional scalar function and an appropriate time-marching scheme is included to enable the discrete level set processing. In the present study, the...

The Anti-lock braking system based on multi-body dynamic and intelligent control theory was researched. A multi-body vehicle dynamic model was built by ADAMS/CAR, and the model included front and rear suspension system, engine system, steering system, antiroll system, brake system, model of tire dynamics and vehicle body model. The model also consi...

A robust design procedure is applied to achieve improved vehicle handling performance as an integral part of simulation-based vehicle design. This paper presents a hybrid robust design method, the robust design process strategy (RDPS), which makes full use of the intense complementary action of characteristics between the Response Surface Methodolo...

This paper investigates a hierarchical optimization procedure for the optimum synthesis of a double-axle steering mechanism by considering the dynamic load of a vehicle which is seldom discussed in the previous literature. Firstly, a multi-body model of double-axle steering is presented by characterizing the detailed leaf spring effect. Accordingly...

This paper presents a new method for topology optimization of geometrical nonlinear compliant mechanisms using the element-free Galerkin method (EFGM). The EFGM is employed as an alternative scheme to numerically solve the state equations by fully taking advantage of its capability in dealing with large displacement problems. In the meshless method...

This paper presents a fuzzy logic control strategy on four-wheel steering(4WS) vehicle based on a multi-body vehicle dynamic model. The multi-body vehicle dynamic model based on ADAMS can accurately predict the dynamics performance of the vehicle. Fuzzy logic is applied to track the yaw velocity of the two degrees of freedom ideal model through the...

The viscoelastic damping is one of key factors that affect vehicle vibration. It has been demonstrated that fractional derivative model can accurately model this kind of fre-quency dependence damping very well. Generally, the excitation of rough road can be acted as a stationary ran-dom vibration process in time domain when a vehicle is traveling a...

In this paper, an approach based on kinematic method for solving 3D geometric assembly constraints is presented. The relative generalized coordinates and generalized recursive formulations used in kinematic analysis are utilized to reduce the size of constraint equations. Based on the cut-constraint method, this approach can be used to solve all ki...

This paper presents an active suspension for a quarter-car model with two Degrees Of Freedom (DOF) using a fractional PI λD μ controller. The active control is expressed as the summation of PI λ and PD μ, which use vertical acceleration of the body and suspension deflection, respectively, as input variables. The parameters of the controller are opt...

In this paper, a CAD model compression approach is presented by representing blending surfaces with their spine curves and variation functions of blending radiuses. The core idea of this approach is to recognize blending surfaces from all B-spline surfaces in a CAD geometry model by analyzing their principle curvature curves, and then extracting th...

Using multi-body dynamics technique, a full vehicle multi-body model for a SUV type is set up with ADAMS. A full vehicle handling stability is simulated and analyzed. A back suspension model which is able to describe its elastic deformation is established by the BEAM principle. According to three estimation methods of the open-loop model handling s...

Due to the clutch's non-linear dynamics, time-delays, external disturbance and parameter uncertainty, the automated clutch is difficult to control precisely during the launch process for automatic mechanical transmission (AMT) vehicles. In this paper, an enhanced fuzzy sliding mode controller (EFSMC) is proposed to control the automated clutch. The...

A new intelligent controlled Four-Wheel Steering (4WS) was proposed by using fuzzy control strategy which was suitable for control nonlinear systems. The proposed 4WS took the side slip angle of the vehicle and yaw velocity of the vehicle as fuzzy control rule input, and the output was the rear wheel steering angle. A fuzzy control strategy model o...

This paper presents an enhanced fuzzy sliding mode controller (EF-SMC) for improving the tracking performance of robotic manipulators, in which the fuzzy logic system is adopted as the adaptation mechanism to tune the gain of the sliding mode controller. The EFSMC can drive the state variables of robotic manipulators to hit a user-defined sliding s...

Vehicle stability control system can enhance the vehicle stability and handling in the emergency situations through the control of traction and braking forces at the individual wheels. This paper presents a Fuzzy synthesis control strategy with an ideal 2-DOF linear model and optimization of the control parameters. The control strategy consists of...