Pneumatic Manipulator Research Articles

Development of a Master–Slave System with Force-Sensing Abilities using Pneumatic Actuators for Laparoscopic Surgery

In minimally invasive telesurgical systems, displaying the forces measured at the slave side is an important issue. The ability to accurately feel the force being applied at the slave side is important. This paper describes a slave manipulator, which has 7 d.o.f. and is driven by pneumatic actuators, newly designed and developed for use in minimally invasive surgery. Then, a master–slave system is constructed using the master device we have developed. In the system, we applied a different impedance control for each manipulator. We adopted a force-control type of impedance control without a force sensor for the pneumatic slave manipulator. For the master manipulator, we used a motion-control type of impedance control. The experimental results indicate that the operator feels the force at the slave side with an uncertainty of about 1.5 N. The effectiveness of the force feedback using the developed system is demonstrated.

Sliding Mode Control of a 2DOF Planar Pneumatic Manipulator

This paper presents a sliding mode controller for a 2DOF planar pneumatic manipulator actuated by pleated pneumatic artificial muscle actuators. It is argued that it is necessary to account for the pressure dynamics of muscles and valves. A relatively detailed system model that includes pressure dynamics is established. Since the model includes actuator dynamics, feedback linearization was necessary to design a sliding mode controller. The feedback linearization and subsequent controller design are presented in detail, and the controller’s performance is evaluated, both in simulation and experimentally. Chattering was found to be quite severe, so the introduction of significant boundary layers was required.

Proxy-based Sliding Mode Control of a Planar Pneumatic Manipulator

For a robotic system that shares its workspace with humans and physically interacts with them, safety is of paramount importance. In order to build a safe system, safety has to be considered in both hardware and software (control). In this paper, we present the safe control of a two-degree-of-freedom planar manipulator actuated by Pleated Pneumatic Artificial Muscles. Owing to its low weight and inherent compliance, the system hardware has excellent safety characteristics. In traditional control methods, safety and good tracking are often impossible to combine. This is different in the case of Proxy-Based Sliding Mode Control (PSMC), a novel control method introduced by Kikuuwe and Fujimoto. PSMC combines responsive and accurate tracking during normal operation with smooth, slow and safe recovery from large position errors. It can also make the system behave compliantly to external disturbances. We present both task- and joint-space implementations of PSMC applied to the pneumatic manipulator, and compare their performance with PID control. Good tracking results are obtained, especially with the joint-space implementation. Safety is evaluated by means of the Head Injury Criterion and by the maximum interaction force in the case of collision. It is found that in spite of the hardware safety features, the system is unsafe when under PID control. PSMC, on the other hand, provides increased safety as well as good tracking.

空気圧平面パラレルマニピュレータの圧力・力センサレス位置・剛性制御(機械力学,計測,自動制御)

This paper presents a method for controlling the position and stiffness of a pneumatic planar parallel manipulator in which the pressure and force sensors are eliminated by replacing them by observers for the purpose of cost reduction. Generally, since pneumatic manipulators are characterized by high nonlinearities such as air compressibility and friction arising in their joints and sliding parts, conventional PID controllers are insufficient for precise control. Using advanced controllers aiming at higher performance requires various sensors, but their dependence on a lot of costly sensors makes pneumatic manipulators less competitive with other power source manipulators in terms of cost. Based on our previous papers, a position controller for the pneumatic manipulator is first discussed in this paper, which introduces observer-based friction compensation for enhancing motion accuracy and pressure observers as substitutes for pressure sensors. The designed controller is further extended in order to control simultaneously the position and stiffness of the manipulator. In this controller, friction observers estimated the contact force between the manipulator's end-effector and a target object, and from these results a force sensor was removed to save costs. Several experiments were carried out to verify the performance of the proposed low-cost controller.

Sliding mode control of a “Soft” 2-DOF Planar Pneumatic Manipulator

This paper presents a sliding mode controller for a “Soft” 2-DOF Planar Pneumatic Manipulator actuated by pleated pneumatic artificial muscle actuators. Since actuator dynamics is not negligible, an approximate model for pressure dynamics was taken into account, which made it necessary to perform full input-output feedback linearization in order to design a sliding mode controller. The design of the controller is presented in detail, and experimental results obtained by implementing the controller are discussed

空気圧マニピュレータの特性を考慮した運動学習システムの提案

空気圧マニピュレータの特性を考慮した運動学習システムの提案

Control of two-axis pneumatic artificial muscle manipulator with a new phase plane switching control method

The use of robots in rehabilitation has become an issue of increasing importance because of the requirement of functional recovery therapy for limbs. A novel pneumatic artificial muscle (PAM) actuator — which has achieved increased popularity for providing safety and mobility assistance to humans performing tasks, as well as providing another advantages such as high strength and power/weight ratio, low cost, compactness, ease of maintenance, cleanliness, readily available, cheap power source, and so on — has been considered during the recent decades for use in a therapy robot, which in particular requires a high level of safety. However, some limitations still exist, such as air compressibility and the lack of damping ability of the actuator to bring the dynamic delay of the pressure response and cause the oscillatory motion. In addition, to aid rehabilitation more efficiently, the robot should adjust its impedance parameters according to the physical condition of the patient For this purpose, the manipulator join is equipped with a Magneto-Rheological Brake (MRB). A new phase plane switching control method using MRB is proposed for tracking sinusoidal waveforms. The effectiveness of the proposed algorithm is demonstrated through an experiment using a fabricated two-axis PAM manipulator. The experiment proves that the stability of the manipulator could be greatly improved using a high gain control without regard to the change of the frequencies of the reference input and the external load condition, and without decreasing the response speed or lowering the stiffness of PAM manipulator.

Study of Web-based integration of pneumatic manipulator and its vision positioning

Pneumatic driven system is widely used in industrial automation, mainly for relatively simple tasks with open-loop control. Because of the pneumatic system’s compressibility and few stop positions, it was considered hard to control in a precise motion control system. With the help of newly developed pneumatic servo control technology, using servo-pneumatic positioning controller now is just as easy as using electro-servo system. This article discusses Web-based servo-pneumatic manipulator control and object recognition and positioning. The authors built a three-degrees-of-freedom (3 DOF) pneumatic manipulator with a servo-pneumatic closed-loop control system and machine vision system in their lab. Web-based tele-operation was a basic ability in this experimental system. After installing a CCD camera, video capture card, and related software developed by the authors, the robot could recognize the user specified object through the Web page and find its position. The remote user could command the robot to move to the position and to grab the object. The critical issues of Web-based control are to integrate hybrid open-architecture mechatronic system through the Web and develop a software language environment characterized by the script. The authors’ experiment showed that pneumatic devices could serve as accurate position control and be controlled through the Web.

Study of Web-based integration of pneumatic manipulator and its vision positioning

Study of Web-based integration of pneumatic manipulator and its vision positioning

On/Off 밸브를 이용한 공압 매니퓰레이터의 고정도 위치제어

Loading/Unloading task in the real industry is performed by crane, but most of the loading/unloading task with the weight of 5kg∼30kg is done by human workers and this kind of work causes industrial disaster of workers. Therefore it is necessary to develop low cost loading/unloading manipulator system to prevent this kind of industrial accidents. This paper is concerned with the design and fabrication of 2 axis pneumatic manipulators using on/off solenoid valves and accurate position control without respect to the external load and low damping in the pneumatic rotary actuator. To overcome the change of external load, switching of control parameter using LVQNN (Learning Vector Quantization Neural Network) is newly applied, which estimates the external loads in the pneumatic cylinder. As an underlying controller, a state feedback controller using position, velocity and acceleration is applied to the switching control system. The effectiveness of the proposed control algorithms are demonstrated through experiments of pneumatic cylinder with various loads.

Occurrence of Trajectory Chaos and It's Stabilizing Control Due to Dead Time of a Pneumatic Manipulator

This research on a 2-link pneumatic manipulator develops from the occurrence of chaos phenomena and it’s stabilizing control in following a circular trajectory by considering a dead time in the system. In generally it is difficult for this manipulator to follow a desired trajectory, because chaos is often caused in the manipulator with a dead time of the pneumatic signal transmitted through the long air tube. In order to solve this kind of problem, the chaos behavior is made clear by recording the Lyapunov exponent of the trajectory, and a new stabilizing method with a neural network is proposed. Through simulations and the experiment, the occurrence of chaos and the possibility of stabilization are verified by using the proposed method.

Phenomena of Chaos in Pneumatic Manipulator with Time-Delay on Trajectory Following and Its Stabilizing Control Using Neural Networks

Phenomena of Chaos in Pneumatic Manipulator with Time-Delay on Trajectory Following and Its Stabilizing Control Using Neural Networks

Design and Analysis of a Novel Pneumatic Manipulator

This paper discusses the design and analysis of a novel “continuum” robot manipulator. The design features two concentric flexible cylinders, with a pneumatically actuated inner tube and with tendons fixed to an outer cylinder. The tendons control bending of the (continuous) structure. Variation of pneumatic pressure allows both extension and the presentation of variable compliance to the environment. Details of the design and implementation of the robot are discussed. Additionally, a novel kinematic model, relating robot shape to tendon lengths, is presented. The design is highly scalable, with a wide range of potential applications.

A Stabilization Control of 2-Link Pneumatic Manipulator by Means of Neural Network

This paper develops with a stabilizing method for hunting of the 2-link pneumatic manipulator. In the pneumatic manipulator, the time-delay exists due to the air tube when air pressure signal is transmitted, and the effect of the pneumatic motor's nonlinear friction is easy to be received. The hunting of each arm is not prevented by the conventional PD control, and it is generally difficult to realize a good stability control. For above problems, the new control method using neural network (NN) is proposed. Through simulation and experiment, the validity and practicability are clarified by this control method.

空気式パラレルマニピュレータを用いた仮想拘束面の導入による操作支援マスタ装置の開発(VRとインタフェース1)

空気式パラレルマニピュレータを用いた仮想拘束面の導入による操作支援マスタ装置の開発(VRとインタフェース1)

2リンク空気圧マニピュレータのむだ時間を考慮した軌道追従におけるカオス発生と安定化制御(OS4-3 マニピュレータ・ハンドとその制御)

2リンク空気圧マニピュレータのむだ時間を考慮した軌道追従におけるカオス発生と安定化制御(OS4-3 マニピュレータ・ハンドとその制御)

218 むだ時間を考慮した 2 リンク空気圧マニピュレータの軌道追従における安定化学習制御

218 むだ時間を考慮した 2 リンク空気圧マニピュレータの軌道追従における安定化学習制御

702 関節制御による空気圧マニピュレータのコンプライアンス制御

702 関節制御による空気圧マニピュレータのコンプライアンス制御

Positional control of pneumatic manipulators for construction tasks

This paper describes solutions that can be applied to pneumatic manipulator problems in positioning, both for angle trajectories and for long linear trajectories, used in construction tasks. Optimal positioning of a pneumatic manipulator along angle trajectories with minimum control energy consumption is given. The implementation of the control system is presented. Control algorithms for a long linear trajectory manipulator based on two-phase and three-phase motion modes of the end-effector are investigated. Conventional and fuzzy logic controls of a pneumatic manipulator were applied and experimental testing was carried out. The obtained results allow widening the application range of pneumatic manipulators in construction, particularly in gantry type machines.

2P2-H03 空気圧マニピュレータによるコンプライアンス制御の静特性解析

2P2-H03 空気圧マニピュレータによるコンプライアンス制御の静特性解析