Ahmad Athif Mohd Faudzi

Development of an Intelligent Chair Tool System Applying New Intelligent Pneumatic Actuators

This paper develops an Intelligent Chair Tool (ICT) — a new chair-type human and machine interaction seating system powered by 36 intelligent pneumatic actuators. This tool can be used to facilitate investigation of chair shapes from spring and damping effects of seating and backrest surfaces. Each actuator used consists of five extensive elements of encoder, laser strip rod, pressure sensor, valves and PSoC microcontroller incorporated in a single device. By using the ICT, different shapes, spring and damping characteristics can be obtained to aid the design of chairs from the control inputs, i.e., position x, stiffness k s and viscous coefficient c. Several control algorithms are presented to realize the communication and control system, and to obtain all data in real-time. The control methodology presented contains an inner force loop and an outer position loop implemented using a unified control system. The specification, development design and experimental evaluation of the ICT control system and actuator used are presented and discussed.

Development of an intelligent pneumatic cylinder for distributed physical human-machine interaction

Pneumatic systems are well known for their advantages and simplicity, and have been applied in various applications. This paper presents the development and experimental evaluation of an intelligent pneumatic cylinder and its control system. The cylinder is designed to have an optical encoder, pressure sensor, valve and a Programmable System on a Chip (PSoC) as the central processing unit. The PSoC will handle I2C communication, input and output data from the analogue to digital converter, counter program and pulse width modulation (PWM) duty cycle. An application tool for a distributed physical human–machine interaction is proposed using an intelligent pneumatic cylinder. The system applied 36 links of the actuator to form an Intelligent Chair Tool (ICT). The control methodology presented contains an inner force loop and an outer position loop implemented using a unified control system driven by PWM to an on/off valve. In this research, four control approaches, i.e., position control, force control, compliance control and viscosity control, were constructed and experimented. The physical properties of various objects were also detected by the intelligent cylinder through the detecting function experiment. Finally, an emulation experiment using mass was carried out and the results clearly show the ability of the intelligent cylinder, and the control approaches towards realization of the future ICT application.

Distributed Physical Human Machine Interaction Using Intelligent Pneumatic Cylinders

The increasing use of mechanical devices using compressed air demands for better control approach and faster responds. In this paper, the development and experimental evaluation of an intelligent pneumatic cylinder for distributed physical human machine interaction is proposed. The system applied 36 links of the intelligent pneumatic cylinders to form an Intelligent Chair Tool (ICT) application where each cylinder consists of optical encoder, pressure sensor, valves and a programmable system on chip (PSoC) microcomputer. The cylinder is unique from each other therefore distributed model is essentially implemented. Four extensive control approaches are proposed and experimentally evaluated namely position servo control, force control, compliance control and viscosity control. The control methodology presented contains an inner force loop and an outer position loop implemented using unified control system driven by PWM to an on/off valve. PI controller is used in the force loop to nullify the nonlinearity arising from the compressibility of air. An emulation experiment using mass was also carried out and the results clearly show the ability of the control approaches to verify the future ICT application.

System Identification model for an Intelligent Pneumatic Actuator (IPA) system

Intelligent Pneumatic Actuators (IPA) is a new generation of actuator for Research and Development (R&D). The purpose of this paper is to present the System Identification (SI) technique and procedure for the IPA system. System identification is used to obtain the mathematical model (transfer function) of the IPA system from the measured experimental data. Flow for the SI procedure starts with experimental setup, model structure selection, model estimation, model validation and finally testing with basic controller to prove the operation of IPA system. Auto Regressive with Exogenous Input (ARX) model is chosen as model structure of the system. Based on the input and output data of the system (model validation), best fit criterion and correlation analysis of the residual is analyzed to determine the adequate model to represent the IPA system. The result from SI model shows linear discrete model in order to obtain a discrete transfer function for the IPA system.

Development of Pneumatic Actuated Seating System to aid chair design

This research develops a Pneumatic Actuated Seating System (PASS), a new human-machine interaction tool to aid in chair design. The seating system is powered by thirty six designed intelligent pneumatic actuators. Three attributes are proposed for chair design namely shape, stiffness and damping characteristics. These facilitate investigation of chair shapes from spring and damping effect for seat and backrest surface. The proposed attributes will quantify the relationship between human styles of seating with the developed seating system. This research tool will be used as experimental apparatus for chair design in the area of customized and specialized seating. The system design, instrument and sitting tests are presented. Three subject sitting tests were done to evaluate the current system and confirm the function ability for further optimization technique in selecting the best parameters.

Position Control of Pneumatic Actuator Using Self-Regulation Nonlinear PID

The enhancement of nonlinear PID (N-PID) controller for a pneumatic positioning system is proposed to improve the performance of this controller. This is executed by utilizing the characteristic of rate variation of the nonlinear gain that is readily available in N-PID controller. The proposed equation, namely, self-regulation nonlinear function (SNF), is used to reprocess the error signal with the purpose of generating the value of the rate variation, continuously. With the addition of this function, a new self-regulation nonlinear PID (SN-PID) controller is proposed. The proposed controller is then implemented to a variably loaded pneumatic actuator. Simulation and experimental tests are conducted with different inputs, namely, step, multistep, and random waveforms, to evaluate the performance of the proposed technique. The results obtained have been proven as a novel initiative at examining and identifying the characteristic based on a new proposal controller resulting from N-PID controller. The transient response is improved by a factor of 2.2 times greater than previous N-PID technique. Moreover, the performance of pneumatic positioning system is remarkably good under various loads.

Nonlinear mathematical model of an Intelligent Pneumatic Actuator (IPA) systems: Position and force controls

This paper presents a nonlinear mathematical modeling of an Intelligent Pneumatic Actuator (IPA) systems and comparison of simulation results with existing experimental results of position and force control data. The derivation method of mathematical equation is referred and reviewed from several literatures. From the mathematical modeling, a simulation analysis was done and compared with existing data from previous research. This paper proposed a reverse engineering method from existing real system on the intelligent actuator that focused more on development of hardware and experimental setup to simulation analysis for validation of the developed model. The simulation results show the affirmation of the developed model based on the mathematical derivation work. The simulation results demonstrate the open-loop and close-loop control systems of position and force tracking control. Finally, performance of this system are analyzed and compared. For future research, this simulation can be used for development of new controllers, validation process and can be applied to real system.

Review of modelling and control of flexible-link manipulators

In recent decades, flexible manipulators have been studied by many researchers from robotics, solid mechanics, and control fields. Flexible manipulators have many advantages, including low weight because of the slenderness of the links of the robot. Although the original objective was to take advantages of the slenderness or flexibility in real robots, the challenging dynamics of the systems intrigued interests to employ an experimental flexible manipulator as a test bed to evaluate different modelling or control methods. With such a vast and various literatures, a review is indispensable for researchers who want to adapt their interests with the area. Some valuable review articles have been published, referencing numerous articles on single-link or multi-link flexible arms. This article pays an inclusive focus on trends of the research on modelling and control of multi-link flexible-link manipulators. The scope of this review article is particularly on two-link flexible manipulators, relevant models presented for closed-loop applications, and model-based control. Recent and historical contributions in the modelling and control of flexible-link manipulators are presented and discussed. As regular industrial manipulators normally have multiple links with two long links, that is, upper arm and forearm, this review can introduce advances in considering elasticity effects to robotic researchers.

Design and control of new intelligent pneumatic cylinder for intelligent chair tool application

This research develops a new intelligent pneumatic actuator consisting of five extensive elements in a single device combining software and hardware architecture design. A micro optical encoder chip is used to detect cylinder rod position by reading constructed laser strips guide rod whereas a pressure sensor is used to detect the chamber pressure reading. 2 unit valves of two ports two positions are used to control the cylinder movements by manipulating PWM cycles. These hardware parts are controlled using designed algorithms in PSoC microcontroller. Two control approaches have been tested for the function ability of the actuator which are servo position control and pressure control. The results show that, the actuator is possible to be used for Intelligent Chair Tool application.

Real-time position control of intelligent pneumatic actuator (IPA) system using optical encoder and pressure sensor

Purpose – Intelligent pneumatic actuator (IPA) is a new generation of actuator developed for Research and Development (R&D) purposes in the academic and industrial fields. The purpose of this paper is to show the application of optical encoder and pressure sensor in IPA, to develop a real-time model similar to the existing devices, and to assess the position control performance using a proportional-integrative (PI) controller and a bang-bang controller in real-time. Design/methodology/approach – A micro optical encoder chip is used to detect cylinder rod position by reading constructed laser stripes on a guide rod, whereas a pressure sensor is used to detect the chamber pressure reading. To control the cylinder movements by manipulating pulse-width modulation (PWM) cycles, two unit valves of two ports and two positions were used. A PI controller and a bang-bang controller are used with suitable gain value to drive the valve using PWM to achieve the target actuator position. Findings – The results show the...