Abstracts
Hironao YAMADA
1.VR(Virtual Reality)
- Development
of a Telerobotics System for Construction Robot Using Virtual Reality（abstract）
- Construction
Telerobot System with Virtual Reality(Development of a bilateral
construction robot) （abstract）
- Development
of a Hydraulic Master-slave System for Tele-robotics (Haptic display
device for a usage of hydraulic servo-system) （abstract）
- Control method of a 3-degree-of-freedom motion base for VR system （abstract）
2.Softmechanics
- A Wide
Angle Vision Sensor with Fovea (Design of Distortion Lens and the
Simulated Images) （abstract）
- Cooperative
control of dual-arm robot(Control strategy considering function of human
arm), （abstract）
- Control
of Flexible Arm Robot with Friction Compensation （abstract）
- Self-tuning
Fuzzy Control of Electro-hydraulic Servo System （abstract）
3.System Control/Mechatoronics
- Sky-hook Control of Active Suspension System Composed
of High Speed ON/OFFValves（abstract）
- Development of
a High-Speed On/Off Digital Valve for Hydraulic Control Systems Using a
Multilayered PZT Actuator （abstract）
- Development
of a Low Cost High-Speed On/Off Digital Valve using a Bimorph PZT Actuator
（abstract）
- Simulation
of Fluid Dynamics Caused in Kyser Type Ink-jet Head（abstract）
- Sliding
Mode Control Using a Disturbance Observer for an Electro-hydraulic Servo
System（abstract）
- A
Precision Driving System Using Hydraulic Cylinder and High-speed ON/OFF
Valves（abstract）
- etc.
1.VR(Virtual Reality)
·
In this study, we have developed a bilateral telerobotics system for a construction robot using virtual reality. The system consists of a servo-controlled construction robot, two joysticks for operation of the robot from a remote place, and a 3 degrees of freedom motion base. The operator of the robot sits on the motion base and controls the robot bilaterally from a remote place. The role of the motion base is to realistically simulate the motion of the construction robot. In this study, we propose a new method of master-slave control in order to better control the hydraulic actuators which are used for actuating the construction robot. We also developed the tele-operation control system for the construction robot using the TCP/IP protocol and computer graphics. The usefulness of the system is confirmed by the experiments in this study.
Construction Telerobot System with Virtual Reality(Development of a bilateral construction robot)
(Hironao YAMADA, Shinji MUKOTA, Dingxuan ZHAO and Takayoshi MUTO),
Proc. of VSMM98, Vol.1, pp.152-157,1998
A remote control system using bilateral control is useful for restoration work in a stricken area and also in extreme environments, such as space, the seabed, deep underground, etc. Recently, several types of telerobotic construction systems with 3D video feedback have been tested by construction companies. However, the reported working efficiency of remote operation was only 30% to 50% of the working efficiency in direct operation.
The aim of this study was to develop a telerobotic construction system which convey an adequate enough sense of the operation field to the operator by using virtual reality technology. The bilateral construction robot that we constructed consists of a servo-controlled construction robot, two joysticks for bilateral control, a microphone, and a pair of stereo CCD cameras for remote control. The two joysticks control four hydraulic actuators via a computer. The system also has a 3-degree-of-freedom (DOF) motion base with a 3D vision system. The motion base simulates the motion of the robot system so that the operator can get a realistic sense of the operation field. The robot system is controlled bilaterally from a remote place.
In the process of constructing this system, we developed a new method of master-slave control for a hydraulic system which can be used for construction robots. We also developed a tele-manipulation system using the TCP/IP protocol which is widely used for the internet. As a result the validity of the proposed system is confirmed by experiment. The following experiments demonstrate the usefulness of our method of master-slave control.
Development of a Hydraulic Master-slave System for Tele-robotics (Haptic display device for a usage of hydraulic servo-system) Shigeki KUDOMI, Hironao YAMADA; Takayoshi MUTO, 1st FPNI - PhD Symposium Hamburg 2000 20.-22. September 2000, Hamburg, Germany (in print)
In this study, we deal with a bilateral master-slave system for tele-robotics composed of electro-hydraulic servo-systems. In a teleoperated master-slave system, the master has to play two roles, firstly as a reference input device to the slave and secondly as a haptic display device. The haptic display means a function that the operator can feel a force fed back from the slave. In order to produce a haptic-display composed of hydraulic servo-system, we must solve a problem called back-drivability, for which an actuator in hydraulic servo-system cannot be operated freely by means of manual force. As a practical solution for this problem, we propose a driving method of actuator by adopting a force sensor attached to the actuator. Furthermore, in this study, we propose an improved type of parallel control method suitable to control the bilateral master-slave system composed of electro-hydraulic servo-systems.
Control method of a 3-degree-of-freedom motion base for VR system
In this research, we deal with a construction tele-robotic system which can be used, for example, for restoration works in a stricken area. The system consists of a servo-controlled construction robot, two joysticks for operation of the robot from a remote place, and a 3 degree-of-freedom motion base. The operator in this system sits on a chair, which is set up on the motion base. An important problem to be solved in such a system is how the operator can feel the presence of working fields in a high quality. In order to solve the problem, in this study, we propose a method that the operator on a motion base of 3-DOF can feel the presence as if it was brought about from a 6-DOF motion base.
2.Softmechanics
A Wide Angle Vision Sensor with Fovea (Design of Distortion Lens and the Simulated Images) (Y. Suematsu, H. Yamada and T. Ueda), IEEE International Industrial Electronics Conference, USA, pp.1770-1773 (1993).
In this paper a new concept of a vision sensor with fovea is presented and the possibilityof the application for on-line machine control is demonstrated. The proposed vision sensor is designed approximate to the visual mechanism of the human eye, which has a fovea (high resolution attention zone) in its field of view and executes the necessary movements of viewpoint. A distortionlens plays an important role in the system, which enlarges the image in the attention zone and compresses the one in the peripheral zone. The lens has been designed in order to realize thesystem. The specification and characteristics are presented in detail. The results show that the proposed system will work well to recognize the environments of mobile robots.
Cooperative control of dual-arm robot(Control strategy considering function of human arm), (H.Yamada, T.Muto and Y.Suematsu),international Journal of ROBOTICS&AUTOMATION, Vol.14-3,pp.89-95,(1999)
This paper deals with a cooperative control of dual-arm robot which consists of three degrees of freedom parallel links. As is experienced in human arms for manipulating a certain object, the cooperative control is usually realized in such a manner that the main-arm (normally right arm) takes partial charge of force control, by getting a support by the sub-arm (normally left arm) . Inspired by such an individual role for two arms, we intend to adopt a cooperative control algorithm to dual-arm robot. In a practice of control, a method of impedance control is applied to the main-arm for increasing flexibility and stability. On the other hand, a method of integral control is applied to the sub-arm for making easier to support an object. Control performance of the dual-arm robot is tested for two different tasks. Consequently, it is confirmed that the proposed control method is effective for cooperative control of dual-arm robot.
Control of Flexible Arm Robot with Friction Compensation (H.Yamada, T.Muto, Y.SUEMATSU),Proc. of the 3rd APCCM98, pp.355-359,1998
In this study, the control of a flexible arm robot was examined by considering a lumped constant model. We proposed a compensation method that can sequentially estimate Coulomb friction disturbance that occurs on the drive shaft. In the friction compensation algorithm, Coulomb friction was estimated by a state equation with a recursive algorithm that is used as a sort of low-pass filter. The system’s performance was evaluated through experiments. Employing on-line estimation of and compensation for Coulomb friction, a linear quadratic control was successfully applied to stabilize the system.
Self-tuning Fuzzy Control of Electro-hydraulic Servo System (Takayoshi Muto,Ping Yu, Yoshiharu Takeda and Hironao Yamada, Proceedings of the Third JHPSInternational Symposium on Fluid Power, pp.189/194,(1996)
This study deals with a self-tuning fuzzy controller (STFC) applied to an electro-hydraulic servo system. The STFC has a hierarchical structure consisting of an algorithm which is identical to a fuzzy controller in the lower loop, with a tuning algorithm assisting the performance evaluation and parameter modification function in the upper loop. As for the algorithm for tuning in the upper loop, another fuzzy logic was adopted for constructing a fuzzy self-tuner. The whole procedure of STFC was repeatedly performed until an acceptable control level could be achieved. The STFC must be able to assess its performance in order to improve its control strategy. The second part of this study deals with a neuro self-tuning fuzzy controller (NSFC) applied to an electro-hydraulic servo system. The NSFC has a hierarchical structure consisting of a fuzzy algorithm which is identical to the fuzzy controller in the lower loop, with a neural network algorithm being adopted for constructing the neuro self-tuner in the upper loop. The whole procedure of NSFC was repeatedly performed by tuning the input and output gains of the fuzzy controller with the neuro self-tuner, until an acceptable control level was achieved. It could be verified by experiment and digital simulation that STFC and NSFC developed in this study were useful and effective for the control of electro-hydraulic servo system.
3.System Control/Mechatoronics
Sky-hook Control of Active Suspension System Composed of High Speed ON/OFFValves(H.Yamada,Y.Suematsu,T.Muto), 10.Fachtagung Hydraulik und Pneumatik, pp.551-564,(1995)
PWM Control of Hydraulic Active Suspension with High-speed On/Off Valves
In this study, a new system of an active control hydro-pneumatic suspension for automobile is proposed and its dynamic performance is tested. The proposed system is composed of high speed On/Off solenoid valves, in stead of a proportional valve or servo-valve in conventional use. As a method for driving the On/Off valves, the pulse width modulation (PWM) method is adopted. Since the choice of On/Off valves driven in digital mode, such as the PWM method, leads the system to an economical and reliable one, it is expected that the proposed system can realize high reliability and cost reduction. The dynamic characteristics of the system are investigated by experiment and digital simulation. These results are compared with those obtained from a conventional system composed of a pressure control valve, and the availability of the proposed system is confirmed.
Development of a High-Speed On/Off Digital Valve for Hydraulic Control Systems Using a Multilayered PZT Actuator(H.YAMADA, Guy WENNMACHER,T.MUTO, Y.SUEMATSU), Proceedings of the Third JHPS International Symposiumon Fluid Power,Japan,pp.331/336,(1996)
Prototyp eines dynamischen Schnellschaltventiles mit piezoelektrischer Ansteuerung (G. Wennmacher and H. Yamada), Olhydraulik und Pneumatik, Vol.37,No.10, pp.794-797 (1993).
In this study, a high-speed on/off digital valve was developed for use in a hydraulic control system. The device basically consists of a poppet valve acting as the main valve, and a multilayered piezoelectric (PZT) actuator for driving the poppet valve. A hydraulic amplifier was adopted to increase the actuation of the PZT actuator to the poppet valve. A compensation mechanism was set up to reduce this temperature effect in the hydraulic actuation of the PZT actuator. This problem arises when the oil temperature increases and causes the valve displacement to fluctuate slightly.
The static and dynamic characteristics of the device were investigated by experiment and digital simulation. As a result, we found that the switching time of the valve is less than 0.7 ms. Moreover, the valve can be driven by a PWM carrier wave using frequencies of up to 500 Hz . Additionally, the validity of the temperature compensation mechanism was confirmed. Hence this valve may be determined as feasible device.
Development of a Low Cost High-Speed On/Off Digital Valve using a Bimorph PZT Actuator (Hironao YAMADA, Sojiro TSUCHIYA, Takayoshi MUTO and Yoshikazu SUEMATSU), Proceedings of the Fourth JHPS International Symposium on Fluid Power, Japan, pp.591/596,(1999)
In the previous paper based on this study, the authors proposed a high-speed ON/OFF digital valve driven by a laminated piezoelectric (PZT) actuator. One drawback of this digital valve was that the PZT actuator could not produce enough displacement in order to actuate the main valve. Additionally, it may be pointed out that the laminated PZT actuator is considerably expensive for general consumer use. In this study, for the purpose of overcoming such drawbacks, an improved type of high-speed digital valve was developed by adopting a bimorph PZT actuator in place of a laminated actuator. The bimorph PZT is cost-effective to produce and can realize a large displacement; the valve will be financially practical and capable of high performance. To actuate the poppet valve, a nozzle-and-flapper mechanism was adopted in the proposed valve. The static and dynamic characteristics of the new device were investigated by experiment and digital simulation. As a result, we found that the valve could be driven by frequencies of a PWM carrier wave as high as 200 Hz.
Simulation of Fluid Dynamics Caused in Kyser Type Ink-jet Head
This paper deals with fluid dynamics caused in Kyser type ink-jet head. The system of the ink-jet head fundamentally consists of an ink-reservoir, pipe line elements, a ink-chamber and a nozzle. In order to execute a simulation analysis of dynamic performance of the system, we construct a mathematical model of the system. As a mathematical model for the pipe line elements, we adopt a modal model which was proposed by the authors for simulating transient response of hydraulic transmission lines in high accuracy. A main interest of this study is, therefore, to investigate applicability of the modal model into a miniature pipe lines such as used in ink-jet head. In the simulation, pressure responses caused in the ink-chamber are calculated. The results are compared with the measured responses to confirm the validity of the simulation analysis.
Sliding Mode Control Using a Disturbance Observer for an Electro-hydraulic Servo System
(Robust Control for 3-D.O.F. Hydraulic Parallel Mechanism)
This paper deals with a trajectory control for the three degree-of-freedom hydraulic parallel mechanism. The hydraulic parallel mechanism can be expected to use in a field that needs the power and accuracy. Since this parallel mechanism is composed of three electro hydraulic servo systems, the characteristics of the parallel mechanism are influenced by many nonlinear elements or disturbances in electro hydraulic servo system, for example the dead time characteristics and an initial shift of the neutral position of servo valve. In this study, we applied the sliding mode control using disturbance observer as a robust control. As a result, it was confirmed through the experiment and simulation that the validity of the dead time compensation for the sliding mode control and that the influence of the disturbance such as the steady-state error and chattering were notably reduced compared to PD control and conventional sliding mode control.
A Precision Driving System Using Hydraulic Cylinder and High-speed ON/OFF Valves
In manufacturing technology, it is a dominant tendency in recent years that machine tools for machining, grinding and so on, employ electric operated actuators such as a servo-motor equipped with a ball screw. Problems of these electric driving systems are, they are excessively large-sized with complex machineries and expensive, as seen in their application to, for example, NC-machine. In order to solve these problems, this study aims to develop a precision driving system actuated by a hydraulic cylinder. The hydraulic driving system consists of a cylinder and four ON/OFF solenoid valves. The valves are the ones diverted from fuel injector of automobile and thus are able of high speed switching times as large as 1.5 ms. It was confirmed in experiments that the developed system had a moving resolution of 1.2 μm and, as a result, was applicable to a precision driving table for micro processing.
