Guanglei Wu

Dalian University of Technology | DUT · School of Mechanical Engineering

Dear Colleagues, With the advancing of industrialization and the advent of the information age, intelligent robots play an increasingly important role in the increasing applications in various areas; therefore, the control and design of such systems have increasingly attracted attention from industrial and academic communities. This Special Issue...

This work presents a method for optimizing the test trajectory for pick-and-place operation of the SCARA robots, where the clothoid curve was adopted to synthesize the right-angle transition part of the test trajectory and to determine the trajectory shape. The trajectory is planned using the S-shaped motion law in the level of continuous accelerat...

Flexible manipulators have been widely applied in various tasks involving grasping and manipulation, and their unique characteristics in terms of lightweight design and adaptability make them particularly suitable for tackling complex spatial pick-and-place operations. In this work, a Triglide flexible manipulator is presented and developed, based...

This paper deals with the suppression of robotic joint buffetings for enhanced precision of trajectory tracking by means of fuzzy-based super-twist sliding mode control, which is illustrated with a fast pick-and-place parallel robot for material handling. Prior to control design, the joint motions and torques are measure to identify the dynamic par...

This paper presents a Schönflies motion generator actuated by four sliding joints in-parallel with a single mobile platform, of which the robot architecture admits a long and narrow workspace that is adap-tive to the pick-and-place operations. This unique structure can ease the kinematic modeling and singularity identification. The dexterity and si...

This paper proposed a new structure of full-mobility parallel robot, which combined the advantages of high-rotational capabilities and structural simplification, for high-speed operations of material handling. The proposed robot structure integrates lightweight and simple linkages with a relatively complex (i.e., compared to the single platform wit...

Aiming at enhanced suppression of external disturbances and high-precision trajectory tracking of parallel SCARA robot dedicating to fast pick-and-place operations, this work presents the integrated control design of iterative learning algorithm, adaptive control and fuzzy rules, namely, fuzzy adaptive iterative learning control, for such type of r...

This article presents a new three-degree-of-freedom (3-DOF) parallel mechanism (PM) with two translations and one rotation (2T1R), designed based on the topological design theory of the parallel mechanism using position and orientation characteristics (POC). The PM is primarily intended for use in package sorting and delivery. The mobile platform o...

The papers in this volume were part of the technical conference cited on the cover and title page. Papers were selected and subject to review by the editors and conference program committee. Some conference presentations may not be available for publication. Additional papers and presentation recordings may be available online in the SPIE Digital L...

Dear Colleagues, Artificial intelligence (AI) holds great potential for robotics, and enables a wide range of benefits in diverse sectors such as manufacturing and healthcare. The robots are becoming ‘smarter’ and more efficient with the development and help of computer science, while most of the existing robotics systems were created with AI-free...

This article presents a new three-degree-of-freedom (3-DOF) parallel mechanism (PM) with two translations and one rotation (2T1R), designed based on the topological design theory of the parallel mechanism using position and orientation characteristics (POC). The PM is primarily intended for use in package sorting and delivery. The mobile platform o...

三自由度并联机构具有结构简单、造价低、运动控制方便，以及刚度高、承载能力大等特点，目前在工业生产等设备中得到了广泛应用，而其中具有移动和转动混合运动的2T1R并联机构具有更高的研究价值。为了研发和推广2T1R并联机构，提出了一种零耦合度且运动部分解耦的空间2T1R并联机构。首先，对该机构的位置正反解进行了分析，并求解了各构件速度与输入速度之间的关系矩阵；然后，运用基于虚功原理的序单开链法，按照机构拓扑结构分解的顺序，分别建立了各子运动链（SKC）的动力学模型，从而得到了整个机构的逆向动力学模型；最后，对建立的动力学模型进行了算例研究，得到了机构的驱动力和2个SKC连接处的支反力，并将其与基于ADAMS虚拟仿真结果进行了对比。研究结果表明：该2T1R并联机构具有部分运动解耦的优点，且通过仿真对...

本发明提供了一种具有可重构特性的多运动平台的高速并联机构，属于高速并联机器人技术领域。多平台并联机构包括固定平台、四个末端运动平台和八条相同结构的运动支链；每条运动支链包括驱动电机、主动连杆、被动连杆；电机轴线互相垂直的两条相邻的运动支链末端通过万向关节连接同一个末端运动平台；相邻两个末端运动平台之间通过竖直的回转副和两个耦合连杆连接，四个末端运动平台和八个耦合连杆形成闭链结构。该高速并联机构具有四个空间内平动的末端运动平台，可在一个工作循环内同时实现四个目标物体的抓放，有利于提高流水生产线的工作效率，节省时间和劳动力。

本发明公开了一种用于工业机器人的误差补偿方法，属于工业机器人在机加工中的应用技术领域，用于工业机器人的零件铣削加工、大型件的焊接等加工工艺中。本发明通过综合考虑工业机器人在应用过程中的自身重力、所受外力以及动态惯性力，在刚度模型的基础上，根据机器人末端的弹性误差，改变机器人关节的位移输入量，使机器人末端的实际运动轨迹与所需的运动轨迹之间的误差缩小到加工要求的范围内，使两种轨迹无限趋近于重合。本发明的误差补偿方法可提高机械加工的精度和质量，降低误差补偿的成本，具有补偿方法简易的优势。

This work deals with the jerk-continuous trajectory planning for robotic manipulators, by 1 means of the fourth-order S-curve to ensure the motion smoothness. The presented algorithm in this 2 work can make the acceleration and jerk keep in a saturated state, to improve the efficiency of the robot 3 programming and operation. Moreover, a multi-axis...

This paper presents the design and analysis of a family of full-hinged partially-decoupled novel parallel mechanisms (PMs) featuring one/two translation and one rotation (1T1R/2T1R). Firstly, three 2-DOF 1T1R and one 3-DOF 2T1R novel spatial PMs are proposed, according to topology design theory of PM based on position and orientation characteristic...

In this work, a new basic framework of robotic mechanism topology is proposed, which includes: ① two important concepts (i.e., topological structure and kinematic characteristics), ② three basic formulas (i.e., POC equation of serial mechanisms, POC equation of parallel mechanisms (PMs), and DOF formula) and ③ topological structure synthesis method...

This paper presents trajectory tracking control of a fast parallel robot for pick-and-place operations. Aiming at high tracking accuracy of the robot end-effector, fuzzy-based super-twist sliding mode control is designed and is evaluated by observing the joint dynamics, in comparison with the classical computed torque control and among others. The...

This paper deals with the jerk-minimization trajectory planning of robotic arms, in order to meet the increasing demands of the practical tasks that require fast motion planning of highly dynamic real-time movements for the task execution, by means of polynomial curve based trajectory design. By solving a constrained quadratic optimization problem,...

This paper deals with centroid alignment for the spaceflight vehicles that work on orbit under microgravity environment, due to the unavailability of centroid measurement on ground, which is based on the principle of mass–radius products in different configurations of static equilibrium. A physical prototype of articulated mechanism for centroid al...

The two-limb¹ parallel mechanisms (PMs) can have the advantages, in terms of avoidance of mechanical collision, simple architecture, rapid configuration transformation and large workspace volume. This paper consists of two major contents. The first aspect pertains to the design of a class of two-limb PMs with two translations and one rotation (2T1R...

p>This paper presents a new two-limb parallel Schonflies-motion generator, which adopts a pair of alternative spatial modules equivalent to the parallelogram structure. This modular architecture can ensure the enhanced stiffness of the manipulator normal to the motion of the planar parallelogram structure due to the trapezoidal architecture. The pr...

In robotic applications, an efficient path planning in a prescribed environment is the central issue, which is a challenging task for multiple degree-of-freedom (dof) articulated robotic arms. In this light, the path planning for robotic manipulators based on the combined artificial potential field method and bidirectional rapidly exploring random...

Precise control is of importance for robots, whereas, due to the presence of modeling errors and uncertainties under the complex working environment, it is difficult to obtain an accurate dynamic model of the robot, leading to the decreased control performances. This work presents an open-closed-loop iterative learning control applied to a four-lim...

This paper presents elastodynamic modeling and analysis for a five-axis lightweight robotic arm. Natural frequencies are derived and visualized within the dexterous workspace to show the overall performances and compare them to the frequencies when the robotics is with payload. The comparison shows that the payload has a relatively small influence...

Dynamic modeling and control of high-speed parallel manipulators are of importance due to their industrial applications deployed in production lines. However, there are still a number of open problems, such as the development of a precise dynamic model to be used in the model-based control design. This paper presents a four-limb parallel manipulato...

This paper presents a novel three-degree-of-freedom (3-DOF) translational parallel manipulator (TPM) by using a topological design method of parallel mechanism (PM) based on position and orientation characteristic (POC) equations. The proposed PM is only composed of lower-mobility joints and actuated prismatic joints, together with the investigatio...

In this work, the structural design of a structure-simplified parallel Delta robot is presented, by considering the kinetostatics, kinematic dexterity and workspace. An approach to normalize the dimensionally inhomogeneous Cartesian stiffness matrix is introduced, and a stiffness evaluation index is defined by means of the singular value decomposit...

This paper presents a novel three-degree-of-freedom (3-DOF) translational parallel manipulator (TPM) by using a topological design method of parallel mechanism (PM) based on position and orientation characteristic (POC) equations. The proposed PM is only composed of lower-mobility joints and actuated prismatic joints, together with the investigatio...

This paper presents the kinematic design of a translational parallel mechanism (PM) named Vari-Orthoglide by means of the workspace superposition, according to the sub-kinematic chain (SKC) based PM composition principle. The main topological characteristics of the manipulator with two SKCs under study, such as the position and orientation (POC) ch...

This paper presents the analysis and experimental evaluation of robot dynamics and control for a four-limb parallel Schönflies-motion generator dedicating to fast pick-and-place operations, with a different topological architecture from its counterparts for efficient use of shop-floor space. The concise equation of motion is built with principle of...

In this paper, the sensitivity analysis and kinematic calibration of a modified parallel Delta robot are presented. The influence of the variations related to the manipulator components and geometric parameters onto the motion accuracy, including the parallelogram, is studied by means of the variational method. The sensitivity analysis shows that t...

Stiffness is an important consideration in the design and application of parallel robots, since it is a measure of the ability of its end-effector to resist deformation due to an external wrench, i.e., forces and moments. The stiffness issue pertains to the computation of the stiffness matrix and its characterization. The widely used approach that...

The requirements on the parallel PnP robots regarding high speed, high load, high precision and lightweight structure make it necessary to consider the deformation, stiffness, and other dynamic characteristics. Hence, their elastodynamic performances are of importance since higher natural frequencies and low elastic displacements allow higher opera...

Differential kinematics of a robotic manipulator pertains to the mapping between the motion variables in the joint space and those in the Cartesian (or operational, or task) space for the velocity/acceleration analysis, upon the differentiation of the geometric constraint equation with respect to time. The first-order differential kinematics relate...

Dynamic modeling of parallel manipulators is usually grouped into three main modeling approaches, i.e., the Lagrangian formulation, the Newton–Euler equations and the principle of virtual work. This sections firstly introduced the general modeling procedure and principles of the previous approaches in detail. Then, different approaches are applied...

This chapter presents the criteria of performance evaluation for parallel mechanisms with the focus of the kinematic aspects, i.e., workspace, dexterity, motion/force transmission and singularity. Workspace is one of the most important criteria in the design of parallel mechanism, wherein its quality that reflects the shape, size and presence of si...

The evaluation criteria for the design of parallel PnP robots can be roughly classified into two groups, i.e., one relates to the kinematic performance while the other relates to the kinetostatic/dynamic performance. An efficient approach to design robotic manipulators is to employ the optimization technique to take all or most of the evaluation cr...

Kinematic geometry is the fundamentals in the modeling and programming of a robot. In this chapter, rigid body kinematics, purely geometrical aspects of individual positions and of continuous motions of rigid bodies, are studied. We firstly introduce some basic material, e.g., the homogeneous transformation, rotation matrix, and the representations...

This paper deals with the trajectory planning for serial robotic manipulators passing through key points by minimizing execution time, energy consumption and joint jerks. Quintic NURBS curves are adopted to fit the trajectory, of which the trajectory is reparameterized with respect to time for generation of geometric path and motion laws, aiming at...

The author’s extensive experience on forward position solution (FPS) of numerous spatial parallel mechanisms (PMs) leads to an important observation that the type and number of position and orientation characteristics (POC) of the moving platform significantly affect the forward position analysis of PMs. Some specific type of POCs not only makes th...

The present invention relates to the technical field of parallel robots. Provided is a SCARA high-speed parallel manipulator having partially decoupled kinematics applicable to pick-and-place operations in industries. The SCARA high-speed parallel manipulator has a main body consisting of two kinematic chains, and comprises motors concealed inside...

Stiffness and performance of Delta-CU were studied herein. Compliance model of limb was established by using virtual spring method, and the static equations of the limb were given. Kinematic differential mapping was obtained by the screw theory, and the Cartesian stiffness matrix of the mechanisms was obtained by making use of the static equations....

This paper has an interesting observation, i.e., the selection of the loop virtual variable position has an important effect on the direct kinematics analysis of PMs. The correct selection of the virtual variable position will directly affect the effectiveness of solving the direct kinematics of a PM and even affect the form of the direct kinematic...

According to the topology design method of parallel mechanism based on position and orientation characteristic equations, a new type of three-translation parallel mechanism with symbolic forward position solution and partial motion decoupling is designed. Firstly, its topological characteristics such as position and orientation characteristic, degr...

This book discusses the parametric modeling, performance evaluation, design optimization and comparative study of the high-speed, parallel pick-and-place robots. It collects the modeling methodology, evaluation criteria and design guidelines for parallel PnP robots to provide a systematic analysis method for robotic developers. Furthermore, it gath...

This paper presents a three-degree-of-freedom fully parallel robotic wrist and its preliminary kinematics. This mechanism actuated by spherical four-bar linkages originates from a spherical parallel manipulator with co-axial inputs. The inequalities to determine the orientation workspace is derived and numerically illustrated, which shows that the...

This paper presents a four-limb parallel manipulator, whose end-effector adopts helical joint to connect two subparts of the mobile platform to enhance the rotational capability. The kinematic Jacobian matrices of subparts of mobile platform are derived to derive the dynamic model that is evaluated by simulation software package for effectiveness....

Over the past several decades, parallel robots have attracted lots of attentions in both academia and industries, which have been widely used as mechanical architectures. Amongst the various types of parallel robots, pick-and-place (PnP) robot is a family of the most popular robots for material handling, leading to its successful industrial applica...

According to the topological design theory and method of parallel mechanism (PM) based on position and orientation characteristic (POC) equations, this paper studied a 3-DOF translational PM that has three advantages, i.e., (i) it consists of three fixed actuated prismatic joints, (ii) the PM has analytic solutions to the direct and inverse kinemat...

According to the topological design theory and method of parallel mechanism (PM) based on position and orientation characteristic (POC) equations, this paper studied a 3-DOF translational PM that has three advantages, i.e., (i) it consists of three fixed actuated prismatic joints, (ii) the PM has analytic solutions to the direct and inverse kinemat...

According to the topological design theory and method of parallel mechanism (PM) based on position and orientation characteristic (POC) equations, this paper studies a 3 DOF translational PM that has three advantages, (i) it consists of three actuated prismatic joints, (ii) the PM has analytic solution to the inverse and direct kinematics problem,...

With the development and popularization of internet and cellphone, Internet + education has become a trend for the teaching/learning mode reform. To improve teaching/learning quality and efficiency of mechanism and machine theory (MMT) course, an APP teaching/learning mode and quality evaluation approach are presented in this paper, aiming at culti...

This paper studies the singularities of a four-limb parallel Schönflies-motion generator. The end-effector design adopts a planetary gear train as the amplification mechanism to realize the full-circle rotation. The singularity is analyzed by means of Jacobian-based method, which are applicable for the singularity identification graphically and num...

This paper deals with the experience of the learning/teaching on Theory of Mechanisms and Machines carried out in Dalian University of Technology (DUT, China) for the undergraduates in Mechanical Engineering. The project-based learning methodology is adopted, and the learning/teaching approach of DUT is briefly presented. The education aspects, for...

This paper deals with the dynamic torsional stability problem of a family of partially-decoupled spherical parallel manipulators. The linearized equations of motion of the mechanical system are established to analyze the stability of the U-joint mechanism, resorting to the Floquet theory. Parametric stability charts of misalignment angles versus ro...

This paper deals with the dimensional synthesis of a cam-follower based drawing-in mechanism for the automatic warp tying machine. The drawing-in mechanism is modeled and introduced. The corresponding drawing-in processes in the textile products is depicted in 4-5-6-7 polynomial equation. The approach of the kinematic geometry is adopted to design...

This paper deals with motion planning of a 5-DOF anthropomorphic robotic arm. The CAD model of the robot is built and converted into a URDF file for the simulation with the ROS platform. Sequentially, the motion planning of the manipulator is completed through the MoveIt! Package. The motion process is observed in RViz, with the planned result bein...

The Delta-CU parallel mechanism is a semi-symmetrical 3-DOF translational parallel mechanism designed by the author based on the topological structure design theory of POC equation. Compared with the Delta mechanism, the structure is more simple, and the kinematics performance is consistent. The stiffness modeling and characteristics of Delta-CU me...

Based on the reliability analysis, this work presents a model of the preventive maintenance for the hydraulic system of platform firefighting vehicle, considering the working age regression factor and the equivalent service life. In this model, both the equipment availability and average maintenance cost are treated as the objective functions and c...

Parallel robot manipulator with the function of space three translations and one rotation (3T1R) is widely used in industry because of its advantages of large working space, easy to realize high speed and low cost. The stiffness performance of a new 3T1R asymmetrical parallel mechanism is analyzed. Firstly, the topological structure of the mechanis...

This paper presents a four-limb parallel Schönflies motion generator for the pick-and-place application, whose end-effector is composed of a planetary gear train as the amplification mechanism to realize the full-circle rotation. The kinematic aspects, including the workspace, dexterity and singularity, are analyzed and evaluated. The singular conf...

There is a wide range of industrial applications for the 4 DOF parallel mechanism which can achieve SCARA type output motion (three dimensional translation and one dimensional rotation). A novel four degree of freedom high speed parallel robot mechanism for SCARA was proposed, which consisted of two RSS branches and two R(SRS)2R branches. Firs...

This paper introduces a new four-limb parallel Schönflies motion generator for the pick-and-place application, whose end-effector adopts a planetary gear train as the amplification mechanism to realize the full-circle rotation. The preliminary kinematic analysis and workspace/dexterity evaluation are carried out to depict the workspace quality and...

In this article，a parallel shaker’s main drive mechanism with the single-degree-of-freedom input as well as the three-translational and one-rotational output is taken as the example，and the decoupling-design method is adopted to reduce the coupling degree from 2 to 1． By means of the parallel-mechanism topology design，both the mechanism’s drive pai...

In this paper, a new three-degree-of-freedom (3-DOF) reconfigurable spatial parallel mecha-nism(PM), i.e., RPa3R-R+RSS, is proposed based on the position and orientation characteristic (POC) equation.Then, the output motion characteristics of the PM is analyzed, which shows that the moving platform can produce n-translation and one-rotation motion,...

The three-translation and one-rotation (3T1R) parallel manipulator (PM) with zero coupling (κ=0) and motion decoupling can have the advantages in terms of simple kinematics, dynamics modeling analysis, and control. In this paper, a novel 3T1R PM is proposed, according to the topological design theory of PM based on the POC equations, of which redun...

This paper deals with the lateral dynamic stabilities for a family of 3-DOF partially decoupled spherical parallel manipulators featuring infinite end-effector rotation. Considering the influence of the rotating speed of the input shaft of the U-joint mechanism, the linearized equation of motion for the lateral vibrations of the manipulators is dev...

In this paper, the 3-RRR spherical parallel manipulator (SPM) of co-axis input is redesigned with reconfigurability. By utilizing a simple four-bar linkage, the SPM is able to change virtually the dimensions of driving links. The new design allows the SPM reconfigurable for investigation of the influence of the link dimensions on the kinematic and...

MeTrApp 2019, the 5th IFToMM International Conference on Mechanisms, Transmissions and Applications, is organized by the School of Mechanical Engineering of Dalian University of Technology, China, October 9-11, 2019. MeTrApp is international conference organized every two years since 2011 to offer a stage for original research presentations for re...

In this paper, the dynamic stability problem of a parallel wrist mechanism is studied by means of monodromy matrix method. This manipulator adopts a universal joint as the ball-socket mechanism to support the mobile platform and to transmit the motion/torque between the input shaft and the end-effector. The linearized equations of motion of the mec...

In this paper, the dynamic lateral stability problem of an asymmetrical spherical parallel manipulator is studied by means of a monodromy matrix method. This manipulator adopts a universal joint as the ball-socket mechanism to support the mobile platform and to transmit the motion/torque between the input/output shaft. The linearized equations of m...

This paper deals with the topological architectural optimization and results in the enhanced kinematic performance for a 3-dof planar traditional parallel manipulator (TPM). A 3-dof planar zero coupling degree manipulator (ZCDM) is proposed based on the method of reducing coupling degree, of which the forward kinematic problem is simplified, leadin...

In this paper, a new 3T1R partially motion-decoupled parallel manipulator (PM) with low coupling degree of κ = 1 and one redundant actuation chain is proposed. The topological design of the PM is introduced. Then the direct position analysis is developed by the molding method based on ordered single-opened-chain (SOC) units. The direct kinematics m...

This paper presents a simple and effective closed-form method for solving direct kinematics of parallel mechanism (PM) based on ordered single-open-chain units (SOCs). The method includes two steps. The first step is to establish the kinematic constraint equations that contain the least virtual variables of a PM, by using the modelling principle ba...

This paper deals with the dynamic stability problem of a tripod parallel robotic wrist by means of monodromy matrix method. This robotic wrist can generate a continuous end-effector rotation in any configuration within its orientation workspace, which allows the manipulator to function as a machine tool head used for a drill point grinder. The syst...

In this paper a new asymmetric 3-translational (3T) parallel manipulator, i.e., RPa(3R) 2R+RPa, with zero coupling degree and decoupled motion is firstly proposed according to topology design theory of parallel mechanism (PM) based on position and orientation characteristics (POC) equations. The main topological characteristics such as POC, degree...

This paper investigated the motion/force transmission quality for a class of parallel Schönflies-motion generators built with four identical RR\(\varPi \)RR-type limbs. It turns out that the determinant of the forward Jacobian matrices for this class of parallel robots can be expressed as the scalar product of two vectors, the first vector being th...

This paper presents a HEXA parallel robots with reconfigurable platforms of Schönflies motion and its kinematic study. Four limbs of the robot forms a fully parallel Schönflies-motion robot, with a six-bar linkage to locate the second end-effector. The second end-effector is constrained by a four-bar linkage subject to a prescribed pose of the firs...