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This paper proposes the use of the integral sliding mode control (ISMC) based on the barrier function to control the servo actuator system with friction. Based on the barrier function, the main features of the ISMC design were preserved, additionally, the proposed control design is done without the need to know the bound on the system model uncertainty, accordingly, the overestimation of the control gain doesn’t take place and the chattering is eliminated. Moreover, the steady-state error can be adjusted via selecting the barrier function parameter only. The simulation results demonstrate the performance of the proposed ISMC based on the barrier function where the system angle successfully follows the desired angular position with a small pre-adjusted steady-state error. Additionally, the obtained results clarify superior features compared with a traditional ISMC designed to the same actuator.

A hydraulic servo actuator with passive compliance (HPCA) is designed for hydraulic actuated quadruped robots, aiming to solve the response discrepancy of the low-bandwidth servo valve to impact forces between robot's feet and the ground. This paper focuses on the performance of this passive compliance method combined with an active compliance control strategy when used on quadruped robots. First, the frequency-response characteristics of the HPCA are further discussed. Then, combined with the requirements of the quadruped robot, a compliant method characterized by incorporating dynamic feedforward control and joint angle feedback control items into the virtual model is proposed. Finally, both the new algorithm and the performance of the HPCA are verified by simulation and experiment. The results demonstrate that, compared with the original actuator, the frequency-response characteristics of the HPCA have better adaptability for the quadruped robot, while the efficiency of the active compliance control is also improved by this novel passive compliance strategy.

Actuator performance is an important factor limiting the dynamic characteristics of the robot. In this paper, the energy transfer capability of the hydraulic servo actuator is improved by adding a miniature accumulator. We established the dynamic model of the system and obtained the optimal inflation pressure of the gas in the accumulator by numerical method. Both numerical analysis and virtual prototype simulation show this design can enlarge the work of the actuator to about 1.66 times the original. It allows the actuator to maintain high performance while reducing mass and volume.

In order to solve the seal problem both the cylinder chamber of the servo actuator in a severe environment, a new hydraulic lock was designed by applying new composite material PEEK and valve injection technology in this paper. The life test and the seal effect of that were carried out. The results implied that the cylinder chamber of the servo actuator was locked in any position. And the hydraulic lock has been applied on the launch vehicle successfully.

To resolve the complexity and uncertainty between the fault portent and the causes of electric and hydraulic actuator, a fault diagnosis model base on neural network arithmetic for actuator is designed. The genetic optimization arithmetic is used to initialize the value of weight and bias to improve the search efficiency and global convergence of the network. The simulation result indicate the feasibility and validity of the method based on genetic neural network model to diagnose the faults of electric and hydraulic servo actuator.

This paper addresses the experimental identification of a servo actuator which is used in many industrial applications. Because the system consisted of electrical and mechanical components, the behavior of the system was nonlinear. In addition, the under load behavior of this servo was different. The load torque was considered as the input and a two input-one output model was presented for this servo actuator. Special focus was given in order to present a simple model for this servo actuator. The comparison between simulation and experimental results showed the effectiveness of the propose model. The model can be applied as a reference for characterizing different designs and future control strategies.

In this paper, we propose a new prototype model of the active guide wire microcatheter whose bending has two degrees of freedom. The design and fabrication methods of this active microcatheter are described. It is 3Fr, 4Fr, 6Fr (1Fr=1/3mm)in diameter and consists of catheter tube and active guide wire with ICPF on its front end as the servo actuator. The bending motion and bending angle of the active guide wire microcatheter have been measured by application of electricity in water and in physiological saline solution. We also modeled this active microcatheter. Experimental results show that the model of the active catheter is reasonable for practical applications. By using simulators (conditions similar to those of a body cavity), we also carried out simulation experiments in vitro. The experimental results indicate that the proposed active guide wire catheter is applicable to intracavity operations.

This paper mainly focuses on the design of a novel type of intelligent DDV actuator system for aeroplane. The function, structure principle and redundancy management of the intelligent DDV (Direct-Drive-Valve) servo actuator system for aeroplane is described in detail. The intelligent DDV servo actuator which is the important part of the system is also described in the paper, including the structure and performance characteristic, the key technique, and so on. An experiment is conducted to verify the dynamic performance and fault monitoring function of the new system. The hardware-in-loop experimental results prove that the design and application of the intelligent DDV servo actuator system on some aeroplane could solve the technical problems in real world. Also, the control precision, stability, and fault monitoring of the system can perfectly satisfy the aeroplane control system design requirements.

Servo actuator is one most important section of flying control system, and faults also often happen to it. The fault detection and diagnosis technology is seriously important to improve the reliability of servo actuator. The paper proposes a method of fault diagnosis based on Elman neural network, using its non-linear distributed processing and dynamic feature reflecting ability to detect servo actuator fault. Then, neural network algorithm is applied to simulation. The result indicated that the method could accurately identify the servo actuator fault. Meanwhile, compared with BP neural network, the advantage of Elman neural network in fault diagnosis is confirmed.

We successfully developed new elemental technologies and succeeded in mass-producing of RSF-3B. The RSF-3B became a product that meets the actual market demand of compact, lightweight and high torque. We are currently supplying these actuators to leading-edge customers in university and corporate laboratories, etc. They are being used especially in robot fingers, in industrial picking hands, and in robot hands for various other fields. Fig.3 shows a robot hand application incorporate RSF-3B. RSF-3B is used for driving joint of the tip of a finger.

Microfluid devices have increasing application as analytical systems, biomedical devices, tools for chemistry and biochemistry. Micropump as the carrier of micro-fluidic has attracted more and more attention. In this paper, we propose a new prototype model of a peristaltic micropump using SMA (Shape Memory Alloy) spring actuator as the servo actuator. We simulated the fashion of intestines peristalsis and realized a kind of peristaltic micopump that driving internally. At the same time we introduced the concept of compound output and proposed a kind of compound peristaltic micropump that the mixed liquid flow can be controlled. This paper describes the new structure and the motion mechanism of the micropump and discusses the possibility of the micropump. The flow characteristic of the micropump is measured. The experimental results indicate that the micropump has the satisfactory responses, it is able to make a microflow and the flow proportion can be controlled. This micropump can be applied widely in biomedical applications.

In the medical field and in biotechnology, a new type of micropump such as peristaltic micropump that can supply micro liquid flow has urgently been demanded. It is our purpose to develop a type of peristaltic micropump that has the characteristics of flexibility, driven by a low voltage, good response, safety and working at a kind of peristaltic mode. In this paper, we propose a new prototype model of a peristaltic micropump using SMA (shape memory alloy) spring actuator as the servo actuator. This paper describes the new structure and the motion mechanism of the micropump and discusses the possibility of the micropump. This micropump consists of two diffusers (Inlet) as one-way valve, four pump chambers made of elastic tube, and extrusion poles. The overall size of this micropump prototype is 30 mm in diameter and 14 mm in length. The flow characteristic of the micropump is measured. The experimental results indicate that the micropump has the satisfactory responses, and it is able to make a microflow and very useful for the biomedical applications.

In the medical field and in biotechnology, a new type of micropump such as peristaltic micropump that can supply micro liquid flow has urgently been demanded. It is our purpose to develop a type of peristaltic micropump that has the characteristics of flexibility, driven by a low voltage, good response, safety and working at a kind of peristaltic mode. In this paper, we propose a new prototype model of a peristaltic micropump using SMA (shape memory alloy) spring actuator as the servo actuator. This paper describes the new structure and the motion mechanism of the micropump and discusses the possibility of the micropump. This micropump consists of two diffusers (Inlet) as one-way valve, four pump chambers made of elastic tube, and extrusion poles. The overall size of this micropump prototype is 30 mm in diameter and 14 mm in length. The flow characteristic of the micropump is measured. The experimental results indicate that the micropump has the satisfactory responses, and it is able to make a microflow and very useful for the biomedical applications.

In March 2003, we proposed a small biped-walking home-entertainment robot SDR-4XII (Sony Dream Robot-4XII, a prototype), which was developed for home use and entertainment. As SDR-4XII is developed for home use, it is designed to be safe. And the important roles of the safety features depend on the functions of newly developed robotic actuator “ISA-4” (Intelligent Servo Actuator 4th). The actuator contributes SDR-4XIPs motion control and safety management very much. In this paper we introduce the safety functions which are achieved in the development of SDR-4XII and ISA in detail.

The externally powered orthosis is one of the necessary devices for rehabilitation of paraplegia patients and hemiplegia patients and spinal-cord-injury victims. However, the main problems of speed, noise, and weight and so on make the morale of the training lower. Then, we thought that there were problems in the actuator. To overcome these problems, we have developed the orthosis externally powered by bi-articular muscle mechanism with a bilateral-servo actuator. Our study suggests such a system as the physically disabled can train with the externally powered orthosis and ambulation device in smooth action.

We propose a new prototype model of micro catheter with active guide wire that has two bending degrees of freedom using an ionic conducting polymer film actuator on its front-end as the servo actuator. In this paper, the bending characteristics of the micro active catheter (MAC) have been measured by application of electricity in the physiological saline solution. By using simulators (whose conditions are similar to those of a body cavity), we have carried out "in vitro" simulation experiments and the contrast experiments of operability between the proposed catheter and a conventional guide wire catheter. The experimental results indicate that the proposed MAC is applicable to intracavity operations.

In this paper, we propose a new prototype model of serial-parallel type of active micro catheter (MAC) with two bending degrees of freedom. It is 4 Fr, 5 Fr and 6 Fr (1 Fr=1/3 mm) in diameter and consist of 3 active units incorporating SMA wires in lumina as the servo actuator. The bending motion, bending direction and bending angle of the MAC have been measured by application of electricity in air and in physiological saline solution. We also modeled this MAC. Experimental results show that the model of the MAC is reasonable for practical applications. By using simulators (conditions similar to a body cavity), we carried out the simulation experiments of "in vitro" and "in vivo". The experimental results indicate that the proposed MAC is applicable to intracavity operations. >

It is our purpose to develop an underwater microrobot that has the characteristics of flexibility, driven by a low voltage, good response and safety in body. In this paper, we propose a new prototype model of an underwater microrobot utilizing ionic conducting polymer film (ICPF) actuator as the servo actuator. The fish-like propulsion using ICPF actuator as a propulsion tail fin for a microrobot swimming structure in water or aqueous medium is developed. The overall size of the underwater microrobot prototype shaped as a boat with a pair of fins is 40 mm in length, 10 mm in width and 2 mm in thickness. The characteristic of the underwater microrobot is measured by changing the frequency of input voltage from 0.1 Hz to 5 Hz. The experimental results indicate that the swimming speed of the proposed underwater microrobot can be controlled by changing the frequency of input voltage.

In this paper, we propose a new prototype model of micro active guide wire catheter that has two bending degrees of freedom. The fabrication methods of this micro active catheters (MAC) are described. Prototype models are 3Fr, 4Fr, 6Fr (1Fr=1/3 mm) in diameter and consist of catheter tube and active guide wire with ICPF (ionic conducting polymer film) on its front end as the servo actuator. The bending characteristics of the MAC have been measured by application of electricity in physiological saline solution. By using simulators (whose conditions are similar to those of a body cavity), we also carried out simulation experiments "in vitro" and the contrast experiments of operability between the proposed catheter and conventional guide wire catheter. The experimental results indicate that the proposed MAC is applicable to intracavity operations.

The development of a machine that supports the movement of the upper limbs has not proceeded for paraplegics. This is because a large output power is necessary in order to move a robot arm while supporting the paralysed body. We propose a new actuator system, called the Hydraulic Bilateral-Servo Actuator (HBSA) system, which has been developed in our laboratory to be applied to powered orthosis with seven degrees of freedom.

In this paper, a new prototype model of microgripper using an ICPF actuator as the servo actuator is proposed. The ICPF actuator is made form the film of perfluorosulfonic acid polymer, chemically plated on both sides with platinum. This paper describes the new structure, the motion mechanism and characteristic measurement of a microgripper using an ICPF actuator.

In this paper, a new prototype model of a micropump using a SMA thin film actuator as the servo actuator is proposed. This micropump consist of two one-way valves that make use of the same SMA thin film actuator. The overall size of this micropump prototype is 12mm in diameter and 20mm in length. The characteristics of the micropump were measured, experimental results indicating that the micropump provides satisfactory responses.

This paper briefly reviews the development of pneumatic servo mechanisms from their origins in the 1950s through to the present day. The constituent elements of representative servo pneumatic actuators are briefly described. Problems somewhat unique to pneumatic motion control are described and some techniques to overcome these limitations introduced. The emergence of digital control of pneumatic actuators are reviewed with respect to the level of performance that can now be realised, types of actuator, associated control components and typical application areas for these systems. A number of application examples of pneumatic servo technology is summarised. The direction for future fundamental research and industrial developments for pneumatic servo technology are suggested.

In this paper, an iron core type LOA is designed and analyzed electro-magnetically for the application to the active control of structural vibration as an active mass driver. Structural vibration is sensored by the accelerometer attached to the structure and reduced by the optimally controlled motion of active mass of LOA giving anti-phase inertia force to the structure. As a result, LOA is confirmed to be applied to the active control of the structural vibration as an servo actuator by controlling the position of armature accurately.

Control system analysts are frequently called upon to include a hydraulic servo actuator as part of the loop in a complex closed-loop system simulation. This article presents a general description of several common types of hydraulic servo actuators and several methods for inclusion of the effects of load on the simulation of the actuator in the control loop. These methods are pre sented in block diagram form and are suitable for inclu sion in a larger simulation loop. The block diagrams themselves may be somewhat condensed and modified before inclusion in a larger simulation, but are presented here with all the details shown explicitly for clarity.

In the medical field and in biotechnology, a new type of micropump that can supply micro liquid flow has urgently been demanded. It is our purpose to develop a type of micropump that has the characteristics of flexibility, driven by a low voltage, good response and safety in body. In this paper, we propose a new prototype model of a micropump using SMA (shape memory alloy) coil actuator as the servo actuator. This paper describes the new structure and the motion mechanism of a micropump using SMA actuator and discusses the possibility of the micropump. This micropump consists of two diffusers (inlet) as one-way valve, a pump chamber made of elastic tube, and a casing. The overall size of this micropump prototype is 16mm in diameter and 74mm in length. Characteristic of the micropump is measured. The experimental results indicate that the micropump has the satisfactory responses, and the proposed micropump is able to make a micro flow and is suitable for the use in medical applications and in biotechnology.

We have proposed a new prototype model of micro-catheter with active guide wire that has two bending degrees of freedom using ICPF (ionic conducting polymer film) actuator on its front end as the servo actuator. In this paper, the bending characteristics of the micro-active catheter (MAC) have been measured by application of electricity in physiological saline solution. By using simulators (whose conditions are similar to those of a body cavity), we also carried out simulation experiments "in vitro" and the contrast experiments of operability between the proposed catheter and conventional guide wire catheter. The experimental results indicate that the proposed MAC is applicable to intracavity operations.