Jing-Feng He

Harbin Institute of Technology | HIT · Department of Mechatronic Engineering

A tensegrity robot is a type of soft-rigid system, whose high compliance is prone to induce structural vibrations which traditionally should be avoided. However, a stable limit cycle oscillation at a natural frequency can be exploited to improve motion efficiency of tensegrity robots. By constructing a modal self-excitation system, we can produce l...

Due to their good motion performance, snake-like robots have been widely studied and researched for years and still have a lot of research interest. In this paper, we propose a snake-like robot based on tensegrity structure. Our snake-like robot is driven with cables on both sides, which is different from the serial structure snake-like robots driv...

In this paper, we propose a hyper-redundant tensegrity bird-neck robotic mechanism. To study the inverse kinematics of this mechanism, we propose a method with two steps. Firstly, the backbone curve for the bird neck is used to describe the macroscopic shape of the mechanism. Secondly, by coordinating the internal forces of the cables when the bird...

A modified dynamic relaxation algorithm for the form-finding of tensegrity robots in task space is proposed in this paper. There are some form-finding problems of tensegrity structures that are hard to be handled by the node-based dynamic relaxation algorithm. For tensegrity structures with multiple interconnected rods or rigid rods, the node-based...

A tensegrity structure is a type of hybrid soft-rigid system, whose high compliance is prone to induce an oscillatory motion. The oscillatory characteristics can be exploited to control a tensegrity structure efficiently, and modal analysis is beneficial in guiding the exploration of the oscillatory characteristics of this type of structures. We de...

For redundant planar rotational parallel mechanisms (RPRPM), stiffness consists of active stiffness resulting from internal forces and passive stiffness caused by compliances of flexible elements, and the active stiffness is coupled with the passive stiffness. The stiffness variations with stretching internal force and compressing internal force of...

An analytical formulation and a new routine are presented to design a maximally regular acceleration sensor based on a generalized Gough-Stewart platform. The Jacobian matrix considering the measuring point is constructed symbolically and also acceleration mapping matrix done. Optimal indices and coupling evaluation are proposed to qualify performa...

Study of methods to design optimal Gough–Stewart parallel manipulator geometries meeting orthogonality is of high interest. The paper will design the Orthogonal Generalized Gough-Stewart Parallel Manipulator (OGGSPM) based on the composite hyperboloids. Moreover, Particle Swarm Optimization (PSO) algorithm is introduced to perform the structure opt...

This paper presents a methodical design of the electro-hydraulic control system for a large scale hydraulically driven six-legged robot, which can walk on rough terrain. Considering the widely varying load during the locomotion cycles, the electro-hydraulic control system should be capable of effectively handling widely varying load and possess hig...

Target image processing requirements of the TV guided missile is high, and the speed is fast, and the quality of target image segmentation is high.In this paper, an improved genetic algorithm based on genetic algorithm is introduced, which is used in the image segmentation of the TV guided missile, and the processing effect is good and the calculat...

In this paper, we consider the problem of modal-space control for the hydraulically driven fully parallel mechanism with actuation redundancy. Firstly, the mechanical-hydraulic interaction system is transformed into modal-space model. Then, independent modal decoupled systems for the redundant mechanism are obtained. According to the eigenvalue fre...

The outstanding characteristics of body and/or caudal fin (BCF) fish, such as the fast speed and high efficiency, have currently attracted the interests of the bionic researches, and some robotic fish have also been constructed. However, there is a huge gap between the biological fish and the fish robot in the swimming performances, which have furt...

In order to overcome the system over-damping caused by the conventional hinged form commonly-used in parallel manipulators in industry, a modal space controller with positive pressure feedback is presented. In this controller, the highly-coupled multiple-input multiple-output systems in the physical space are transformed into six independent single...

A new simple and effective inertial parameter identification method based on sinusoidal vibrations of a six-degree-of-freedom parallel manipulator is proposed. Compared with previously known identification algorithms, the advantages of the new approach are there is no need to design the excitation trajectory to consider the condition number of the...

The traditional Stewart platform cannot achieve complete dynamic isotropy due to its strict payload requirement, while the generalized Stewart platform based on a pair of circular hyperboloid of one sheet gives the analytical form of parameters constraint conditions satisfying local complete dynamic isotropy, and breaks the limit of payload charact...

A novel fault-tolerant control scheme is proposed for the uncertain Stewart platform under loss of actuator effectiveness. The uncertain friction, parameter estimated errors, unmodeled dynamics, and even the unknown actuator faults are analyzed in the controller design, which are open problems in the uncertain nonlinear system control theory and ha...

A novel design method for modal space controller with dynamic pressure feedback is proposed for hydraulically-driven Stewart platforms. By exploiting properties of the joint-space inverse mass matrix, an analytic modal matrix is derived which can be used for transforming the highly coupled multiple-input multiple-output (MIMO) dynamics into six ind...

This paper investigates the trajectory tracking of a Stewart platform, which is a typical multi-input multi-output nonlinear system, with unmodeled dynamics, parameter uncertainties, friction, and unpredictable actuator faults. An adaptive vector sliding mode fault-tolerant control law is derived to ensure the system is insensitive to uncertainties...

A multi-objective optimization method was advanced to make the drag and structure mass minimum of horizontal stabilizer based the precondition of meeting flying qualities. After the optimization, the longitudinal stability reduced, the longitudinal control performance increase. This method has referential meaning for the design of horizontal stabil...

This essay focuses on a new type 2-DOF shaking table, which is driven by four hydraulic cylinders. Taking 2-DOF shaking table for example, in order to conveniently and rapidly achieve the control system simulation, using Simulink for simulation platform and combining with SimMechanics. Build dynamic modeling in SimMechanics and use Simulink to buil...

Simtlink is not only intuitive, but also programming steps can be reduced. The mode on single-phase bridge type all control the rectifier circuit is built which is based on Simulink/ MATLAB. According to the different parameters of circuit simulation, they can further deepen single-phase bridge type all control the rectifier circuit theory, as well...

A servo controller for redundant force is designed based on DOF shaking table. Firstly, according to the geometric position of hydraulic cylinders, the composition and decomposition matrix are achieved. Secondly, in order to reduce the coupling on shaking table, which derives from redundant force within the system, force transformation matrix is ca...

The design using CVRCON control and drive the oscillating circuit, making the oscillating circuit resonant coupling, realizing the wireless transmission of power, and allowing the LED lights can be lit. The key can adjust the sampling resistor value, changing the transmit power, and controlling the LED brightness.

the power spectrum estimation researches various characteristics of signals in the frequency domain. The purpose is that signals are recognized and extract .Because these useful signals are submerged in noise .The article introduces estimation in the classic power spectrum and modern power spectrum. It is important that algorithm of AR model parame...

In this study, we analyze the influence of passive joint viscous friction (PJVF) on modal space decoupling for a class of symmetric spatial parallel mechanisms (SSPM). The Jacobian matrix relating the platform movements to each passive joint velocity is first gained by vector analysis and the passive joint damping matrix is then derived by applying...

Based on introducing the traditional scan and single target tracking state, focuses on the automatic tracking characteristics of each stage under the condition of multiple targets. The two form of automatic tracking multiple targets, and the development direction of the future.

In the light of the backwardness of test means, over-complication in operation and inaccessibly to the test of the system main performance parameters in the case of army equipping Helmet Mounted Sight (HMS), extensive researches are conducted on improvement and home manufacture of HMS in No.×× project, to solve the actual problem of maintenance in...

The state-transition matrix in the linear control system has very important application. The calculation methods of state transition matrix Based on the theorem and an example have been given. Such as the method of Matrix diagonalization, Laplace transform, the matrix exponential function limited direct expansion, the differential equation and the...

This is a ward-called system of 64-bed. Its core component is an AT89C51 single-chip with rich internal storage resources. This system uses 8×8 matrix keyboard as its input device, a 2×8 LED as its static display, a 12MHz crystal oscillator circuit as its timer. A reset button is used to control its reset circuit. With the adoption of AT89C51 singl...

For a six-dimensional force sensor, a key issue in its structural design is to realize low coupling and high precision. A standard Gough-Stewart structure based six-dimensional force sensor is able to achieve the best force isotropy with a value of 0.707, and its intrinsic isotropy performance directly affects the measuring accuracy of a sensor. In...

In this study, we analyze the influence of passive joint viscous friction on modal space decoupling for a class of symmetric spatial parallel mechanisms. The Jacobian matrix relating the platform movements to each passive joint velocity is first gained by vector analysis and the passive joint damping matrix is then derived by applying the Kane meth...

In this paper, we study dynamic isotropy using natural frequency analysis for a class of symmetric spatial parallel mechanisms (SSPMs) with 2p (p≥3) struts. This kind of dynamic isotropy has been defined as the square roots of the eigenvalues of the equivalent mass-spring systems formed via the interactions between rigid-body mechanical systems and...

In this paper, the definition of generalized symmetric Gough–Stewart parallel manipulators is presented. The concept of dynamic isotropy is proposed and the singular values of the bandwidth matrix are introduced to evaluate dynamic isotropy and solved analytically. Considering the payload's mass-geometry characteristics, the formulations for comple...

To ensure high accuracy spaceborne optical instruments with natural precision, a Stewart platform was adopted as a multi-dimensional active vibration isolation system. Considering mass geometry characteristics of payload, the analytical formulation of acceleration isotropy was derived based on the definition of acceleration isotropy. The relations...

Purpose – The precise control and dynamic analysis of the electrical Stewart platform have not been so well treated in the literature. This paper aims to design a novel model‐based controller to improve the tracing performance of the electrical Stewart platform. Moreover, the simulations under uncertain environments are used to verify the robustnes...

The six-dimensional force/torque sensor based on a Stewart parallel structure has great potential for application in the field of precise measurements of spatial forces, and it is a key issue in the structural design to develop a six-dimensional force/torque sensor with low coupling, high precision, ease of calibration and application. Traditional...

This paper proposes an optimal design method for a Gough–Stewart Platform (GSP) with complete dynamic isotropy at a single point. Generally, dynamic isotropic behavior is associated with the geometric structure, which should be carefully designed to match the payload. However, in this work, we use a pair of circular hyperboloids to describe a modif...

A precise tracking-pointing platform should meet such requirements as highly pointing, vibration isolation and vibration suppression. A Stewart parallel manipulator with dynamic isotropy is applicable to satisfy precise tracking and pointing performances, while it is still difficult to realize an optimal design for the desired specification. A trad...

This paper proposes an optimal design method based on dynamic isotropy conditions of a generalized natural frequency matrix in task space for a standard Gough–Stewart parallel manipulator (GSPM). Firstly, the dynamic isotropy conditions are discussed and presented. Next, it is proved that standard GSPMs lie on a circular hyperboloid of one sheet. F...

A shaking table is an important facility for earthquake damage testing of large scale structures like high buildings, large bridges and infrastructural systems. To improve the payload capacity in the test for large-scale structures or real-scale structures, hydraulically redundant actuated parallel mechanisms are usually adopted. By exploring the i...

Geometry parameters and lengths of legs often have close relations with the singularity of a Gough-Stewart platform. When these parameters are improperly selected, the platform may have hunt singularities. The relations among the geometrical parameters and the leg lengths when in hunt singularity for 3-3, 6-3, 6-6 Gough-Stewart are derived accordin...

For an electrical six-degree-of-freedom Stewart platform, it is difficult to compute the equivalent inertia of each motor in real time, as the inertia is time-varying. In this study, an analysis using Kane’s equation is undertaken of the driven torque of the movements of motor systems (including motor friction, movements of motor systems along with...

The hydraulically driven 6-DOF parallel Gough-Stewart mechanism was used as a motion simulator to simulate the real motions of carrier for testing firing control systems in laboratory. The bidirectional force/torque versus velocity interactions between mechanical dynamics system and its hydraulic driving system was explored to establish an integrat...

An optimal design method for the Gough–Stewart platform manipulators based on dynamic isotropy is proposed. First, a dynamic isotropy measure is derived from the analysis of the natural frequencies of a Stewart platform at a neutral pose using the inverse of the joint space mass matrix. Next, considering a specific Gough–Stewart platform (SGSP), it...

Using a hydraulically driven six-FOD motion simulator to simulate the vibration environment, there exist amplitude attenuation and phase lag due to the characteristics of closed-loop amplitude and frequency responses of the simulator. Therefore, it is difficult to achieve accurate track and recurrence of high frequency random signals. To solve this...

A precise integrated dynamics modeling idea is presented to carry out the characteristics analysis and performance prediction of electrical parallel robots using a 6-SPU parallel robot driven by permanent magnet synchronous motor (PMSM) as an example. Motor systems in the electrical parallel robot move with legs, and meanwhile rotors and snails go...

A force control strategy based on the inner loop position control of 6-dof parallel platform was proposed in order to realize the pushing and pulling procedure of forcible alignment in hardware-in-the-loop space docking simulation. Considering the variety of the connection stiffness between two spacecraft, adaptive force controller was designed to...

Log polar transform is not only a mathematical description of the retino-cortical mapping of human vision system, but also a vital algorithm of space-variant resolution theory. The obverse transform algorithm leads to pixel discreteness in the fovea area. Aiming at solving this problem, the inverse log polar transform algorithm based on grey weight...

In order to improve the dynamic response bandwidth of three-stage electro-hydraulic servo valve, a new method, speed-feedback control is presented in this paper. The construction and principle of three-stage electrohydraulic servo valve are explained, and the mathematical model of three-stage electro-hydraulic servo valve is built in frequency doma...

Flight simulator is among the most sophisticated semi-physical simulation systems in existence. It contains hundreds of avionics with thousands of input/output interface points, which must be amenable to frequent updates to maintain high fidelity with the ever-changing vehicle it is simulating. We proposed an optimized avionics interface system to...

This paper presents a novel numerical method, Global Newton–Raphson with Monotonic Descent algorithms (GNRMD), to solve the effectively real-time spatial 6-DOF states of parallel robots in practice. Based on geometrical frame of parallel robots, the highly nonlinear equations of system states estimation are obtained using analytical approach. GNRMD...

Flight simulator is among the most sophisticated software systems in existence. It is highly distributed, has rigorous timing requirements, and must be amenable to frequent updates to maintain high fidelity with the ever-changing vehicle and environment it is simulating. We proposed an optimized distributed real-time simulation framework to facilit...

The real-time distributed computing environment and reusable software architecture are important factors that affect the fidelity of flight simulation. We accomplished a flight simulator based on DDS (Data Distribution Service for Real-time Systems) middleware and structural software architecture and proved its high fidelity as a flight training de...

This paper presents the implementation of the PID based cascade control system for the adjustment of density of starch production line. The control system involves the design of RSLogix500 and RSView32 and was used to adjust the density of the starch production-line. The principle of the starch production-line was analyzed and the mathematical mode...

The multi-rigid body dynamic model of the hydraulic Stewart platform was presented through Kane formulation, and the general mass matrix of the platform was proposed, and then the general stiff matrix of the system was obtained by regarding hydraulic actuator as hydraulic spring. The natural frequency formulation of the platform was derived and thi...

A novel model-based controller for six-degree-of-freedom (DOF) parallel manipulator is proposed in this paper, in order to abatement the influence of platform load variety and compel the steady state errors converge to zero. In this paper, 6-DOF parallel manipulator is described as multi-rigid-body systems, the mathematical model of the 6-DOF paral...

The modeling and study of three-stage electro-hydraulic servo valve are presented in this paper. According to its construction and principle, its model is built. The results of simulation and experimental test are consistent, which proves the validity of the model. Based on the study of the model, the performances of three-stage electro-hydraulic s...

Close chain of spatial mechanical structure of the hydraulically driven Stewart platform makes there exist coupling between the six degrees of freedom. In this paper, it builds the multi-body dynamics model of system with Kane method and then builds the dynamics model of the hydraulic servo system. Combining the two parts, it achieved the whole dyn...

A novel model-based controller for six degree of freedom (dof) parallel manipulator-PID controller with gravity compensation is developed, in order to improve the control precision of six-dof hydraulic driven parallel manipulator with long stroke hydraulic actuator and heavy load. In this paper, six-dof parallel manipulator is described as a thirte...

Three axes hydraulic shaking system as the means to recreate vibration environment can accurately reproduce reference power spectrum density and time history response. The vibration control is a key technique to meet the requirement. This paper introduces the principle of the three-axis six-DOF shaking table at first and then designs hardware syste...

Flight simulator is a large-scale simulation system. Because of the limitation by computer powers, only special computers ever were used to realize flight dynamics simulation and image generation in full flight simulator in the past. With the development of computer powers, high-performance computation and simulation can be realized applying by PC....

This paper presents an analysis of the coupling effects between degrees of freedom of a hydraulic controlled six DOF parallel manipulator. Based on the singular value decomposition to the properties of its joint space inverse mass matrix, the method is put forward to analyze coupling effects between degrees of freedom using a transformation matrix,...

A feasible routine for complex fluid simulation is presented, consisting of the pre-processing and runtime stage. The pre-processing stage generates all computation-aided textures, which speeds up the simulating and rendering at run-time stage. We improve the unreasonable processing in most previous methods and give a correct discretized solution o...

Based on extensive study on literatures of control of parallel manipulators and serial manipulators, control strategies such as computed torque control, PD+ control, PD with feedforward compensation, nonlinear adaptive control are classified into two categories: model-based control and performance-based control. Besides, as advanced control strateg...

Conventional design of 3-DOF motion platform is a serial design, in which physical prototype-based design and verification bring about restrictions to the development period and efficiency In order to realize rapidly and efficiently from the conceptual design to prototype design, it was proposed to combine VR with kinematic analysis, structure desi...

6-DOF Parallel manipulator is a nonlinear MIMO system, and its pose outputs are strongly coupled. Using feedback linearization and linear PD control, only translational motions are decoupled and the rotational motions still exist couplings. To fully decouple the outputs of parallel manipulator, a new decoupling controller based on feedback lineariz...

Shock response of 6-DOF (degrees of freedom) parallel motion platform driven by hydraulic actuators is analyzed. It is observed that the relatively low stiffness of the hydraulic systems constitutes the main cause for the pose error of motion platform under shock. Shock response of the hydraulic systems has first been obtained, and then with the er...