Parallel Link Robot Research Articles

Formulation Method of Robot Kinematics Considering Versatility and Mobility of Each Joint

This paper proposes a method of formulating the robot kinematics. The proposed method can be applied to mobile manipulators, parallel link robots, and legged robots by the same procedure. The proposed forward kinematics formulation is based on tree-structured rigid-body system and is compared with the Denavit–Hartenberg method and URDF. The proposed differential kinematics formulation is represented by a block lower triangular matrix, which is a generalized form of the basic Jacobian matrix. In addition, an application example of the proposed formulation to the numerical inverse kinematics method is also shown. The usage of the proposed method is demonstrated by simulation experiments using a dual-arm mobile manipulator and a parallel link robot.

Metaheuristic Identification for an Analytic Dynamic Model of a Delta Robot with Experimental Verification

The dynamic-parameter identification process for developing a suitable precise mathematical model for the implementation and operation of parallel-link robots has received attention. In this study, an efficient and reliable system-identification method for a delta robot is proposed. The parallel-link robot’s dynamic behavior was mathematically modeled according to the principle of virtual work. The dynamic equations of motion are extended to the system of equations that explicitly characterizes the inertial and centripetal/Coriolis forces, and the frictional effects on the robot’s dynamic behavior. Next, the dynamic-parameter identification technique is presented to directly estimate a set of uncertain parameters that are included in the extended dynamic model. In addition, the development of the dynamic model with a generalized inertia matrix for determining the impact of the inertia-coupling characteristic on the robot’s dynamic behaviors is examined. Experimental results indicate that the proposed parameter-estimation technique is an extremely useful tool that can achieve the high-quality identification of an analytic dynamic model for a parallel-link robot.

Kindai University: Advanced Robotic Technology Research Center in Fundamental Technology for Next Generation Research Institute

An outline of the Advanced Robotic Technology Research Center, Kindai University Fundamental Technology for Next Generation Research Institute is given. The research activities of the Advanced Robotic Technology Research Center are classified into the following five fields, field robotics, medical and welfare robot, dynamics controlled robot, soft-robotics, and parallel link robot.

SELF-LEARNING OF DELTA ROBOT USING INVERSE KINEMATICS AND ARTIFICIAL NEURAL NETWORKS

As known as Parallel-Link Robot, Delta Robot is a kind of Manipulator Robot that consists of three arms mounted in parallel. Delta Robot has a central joint constructed as an end-effector represented as a gripper. An Analysis of Inverse Kinematic (IK) used to convert the end-effector trajectory (X, Y) into rotations of stepper motors (ZA, ZB and ZC). The proposed method used Artificial Neural Networks (ANNs) to simplify the process of IK solver. The IK solver generated the datasets contain motion data of the Delta robot. There are 11 KB Datasets consist of 200 motion data used to be trained. The proposed method was trained in 58.78 seconds in 5000 iterations. Using a learning rate (α) 0.05 and produced the average accuracy was 97.48%, and the average loss was 0.43%. The proposed method was also tested to transfer motion data over Socket.IO with 115.58B in 6.68ms.

Calibration control to maintain US focal point accuracy and its application to parallel link robot

Calibration control to maintain US focal point accuracy and its application to parallel link robot

Calibration control to maintain US focal point accuracy and its application to parallel link robot

Calibration control to maintain US focal point accuracy and its application to parallel link robot

Development of Haptic Interface for Dental Palpation Training System using Parallel Link Robot

Development of Haptic Interface for Dental Palpation Training System using Parallel Link Robot

A study on tolerances design of parallel link robots based on mathematical models

A study on tolerances design of parallel link robots based on mathematical models

パラレルリンク型ロボットを用いた血管内カテーテルの超音波誘導システムの構築

Microbubbles are expected as carriers of acoustic targeted drug/gene delivery therapy. Because microbubbles diffuse in human body after injection, we have proposed a technique that controls catheter which can deliver microbubbles directly to the target position in blood vessels using ultrasound emitted from the body surface. To apply this technique in vivo, robotic positioning of therapeutic devices on body surface is required. For this purpose, we have developed a robotic system using parallel link robot, which has both diagnostic/therapeutic devices. In this paper, first we describe the algorithm of ultrasonic catheter control system. Then, we performed the accuracy evaluation of focal point using robotic positioning. The accuracy was about 1.5 mm, which is less than the beam width of sound pressure distribution. Finally, we demonstrated the ultrasonic catheter control experiment at the bifurcation of in vitro blood vessel and the catheter was controlled to the target path in 100% induction rate.

定荷重ばねを用いたパラレルペア・パラレルワイヤロボットの高速動作時の位置決め制御実験

For high speed pick-and-place work, we develop a 3 D.O.F parallel paired cable robot motivated by Dleta type parallel link robot. The robot consists four paired parallel wires enabling always keeping horizontal motion which is suitable for pick-up-place task. The paper proposes a mechanism using constant force spring to reduce the motor torque of the robot and high stiffness. The paper also shows advantages of using the constant force spring by position control experiments.

Contact force control of therapeutic ultrasound device on body surface using parallel link robot

Contact force control of therapeutic ultrasound device on body surface using parallel link robot

Hybrid position/force control system of the ultrasonic treatment device by parallel-link robot

Hybrid position/force control system of the ultrasonic treatment device by parallel-link robot

Applying High-Speed Vision Sensing to an Industrial Robot for High-Performance Position Regulation under Uncertainties.

It is traditionally difficult to implement fast and accurate position regulation on an industrial robot in the presence of uncertainties. The uncertain factors can be attributed either to the industrial robot itself (e.g., a mismatch of dynamics, mechanical defects such as backlash, etc.) or to the external environment (e.g., calibration errors, misalignment or perturbations of a workpiece, etc.). This paper proposes a systematic approach to implement high-performance position regulation under uncertainties on a general industrial robot (referred to as the main robot) with minimal or no manual teaching. The method is based on a coarse-to-fine strategy that involves configuring an add-on module for the main robot’s end effector. The add-on module consists of a 1000 Hz vision sensor and a high-speed actuator to compensate for accumulated uncertainties. The main robot only focuses on fast and coarse motion, with its trajectories automatically planned by image information from a static low-cost camera. Fast and accurate peg-and-hole alignment in one dimension was implemented as an application scenario by using a commercial parallel-link robot and an add-on compensation module with one degree of freedom (DoF). Experimental results yielded an almost 100% success rate for fast peg-in-hole manipulation (with regulation accuracy at about 0.1 mm) when the workpiece was randomly placed.

パラレルリンクロボットを用いた患者体表面における超音波治療器具の面接触制御

For ultrasound therapy, e.g. microbubbles delivery, physical contact between therapeutic device and body surface is important. To guarantee the entire contact of the device, we propose a control method considering contact force and reaction moment using a robotic system and sensors. We used a parallel link robot, which has three links and the holder to determine position and angle of the device. First we established a series of surface contact controls, which consists of (a) initial contact control, (b) balance contact control, and (c) angle restoration control. Second we eliminated self-weight moment of the device using the sensors. Next we proposed a measurement method of elasticity coefficient of soft material. Then we performed evaluation experiments using soft material and human body. In the experiment using soft material, contacted area was visualized and evaluated with color ink. In the experiment using human body, convergence time to the desired position and angle was also evaluated while monitoring contact force and moment. We concluded that the determination of appropriate parameters is important and dominant for the quality of the system.

パラレルリンクロボットの構成要素の幾何公差に基づく公差設計に関する研究

パラレルリンクロボットの構成要素の幾何公差に基づく公差設計に関する研究

作業空間における適応制御を用いたむだ時間のあるバイラテラル制御系の設計

It is effective for improving stability of the bilateral teleoperation with time delay that the adaptive control which dynamically changes master’s position controller gain depending on the stiffness of a contact object. In the previous study, the controller was designed in joint space only. It is necessary with the different structure master - slave system to design the controller in work space for the bilateral teleoperation. In this paper, we design the adaptie controller in work space and verify on the 2DOF parallel link robots system.

Prototype Development of a Parallel-Link Robot Actuated by Pneumatic Linear Drives with Variable Inclination Mechanisms

Parallel-link robots are generally high in power and precision because of their parallel arrangement of actuators. However, they have a workspace smaller than that of serial-link robots. In this paper, we develop a parallel-link robot prototype with pneumatic linear drives in which a mechanism for varying the actuator inclination is incorporated to enlarge the workspace. Our parallel-link robot realizes the rotational and translational motions of the end effector principally by means of the linear reciprocating motions of pneumatic linear drives mounted on the base. Auxiliary pneumatic actuators are used to adjust the inclination angles of those main pneumatic linear drives. The use of pneumatic actuators to realize the proposed parallel-link robot results in a lightweight, compact, and low-cost construction. The workspace and motion transmissibility of our parallel-link robot are analyzed through simulations based on kinematics; then, experimental investigations are carried out using the prototype.

1A1-B05 2本平行型3自由度完全拘束パラレルワイヤロボットの提案(ワイヤ駆動系の機構と制御)

This paper proposes a three D.O.F completely restrained parallel wire robot with four motors which enables fast three D.O.F positioning. The control of orientation for the end-effector part by the conventional three D.O.F completely restrained parallel wire robot is impossible. Because, the motion D.O.F by four motors is used only for three D.O.F positioning without considering the orientation of the end-effector part. The end-effector part of the mechanism should move keeping horizontal orientation when considering actual tasks such as pick and place. The characteristic of keeping with horizontal orientation has been realized by "rigid type" parallel link robot such as Delta robot. This paper proposes a new mechanism to realize the characteristic keeping with horizontal orientation for three D.O.F completely restrained parallel wire robot. By using parallel paired wires for one motor, the end-effector part always moves with keeping horizontal orientation for any positioning point in the work space of the robot.

Position Control of Ultrasound Transducer by Parallel Link Robot for Ultrasonic Therapy in Blood Vessel

Position Control of Ultrasound Transducer by Parallel Link Robot for Ultrasonic Therapy in Blood Vessel

Innovation of the Production Process by Parallel Link Robot

Innovation of the Production Process by Parallel Link Robot