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Trajectory Tracking Control of Multi-DOF Robot without Considering System Dynamics
Saad Jamshed Abbasi,Hamza Khan,이민철 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.9
In this study, two different control logics have been designed for the position control of a robot with five degrees of freedom (DOFs). First, a sliding mode control with a sliding perturbation observer (SMCSPO) has been proposed. The SMCSPO is robust against perturbation, which is the sum of nonlinearities, parametric uncertainties, and external disturbances. To implement the SMCSPO, linear parameters of the system are required; however, these are difficult to identify. Moreover, it is exigent to derive the equation of motion for the multi-DOF robot. Accordingly, an integral sliding mode control (ISMC) has been designed for the position control of this multi-DOF robot. The ISMC controller does not require a mathematical model of the system. The ISMC control input applies a switching gain to compensate for the perturbation and system dynamics. In comparison with the SMCSPO, the ISMC has improved the tracking performance of the system because of its unique characteristics. Both control schemes have been implemented in MATLAB/Simulink. It has been observed that the tracking error of each ISMC joint is lower than that of the SMCSPO.
Robust Position Control of Assistive Robot for Paraplegics
Hamza Khan,Saad Jamshed Abbasi,Karam Dad Kallu,Hyun Hee Kim,Young-Jun An,Min Cheol Lee 제어·로봇·시스템학회 2021 International Journal of Control, Automation, and Vol.19 No.11
Paraplegia refers to the paralysis of the lower limbs resulting from the damage to the spinal cord. Thus far, considerable efforts have been devoted to the rehabilitation of paraplegics and the improvement of their qualityof life. This study focuses on the position control of the sit–stand mechanism of an assistive robot developed to aid paraplegics in shifting from a sitting to a standing position and vice versa. Two control techniques for the modelwere proposed: sliding mode control (SMC) and SMC integrated with a sliding perturbation observer (SMCSPO). The control algorithm was designed and implemented in MATLAB/Simulink. The simulation results indicate thatthe SMC is a nonlinear control; however, because the robot is a highly nonlinear model, which requires a high switching gain, the controller introduces chattering into the system. The SMC has been observed to exhibit inadequate performance when controlling a system with uncertainties. In contrast, the SMCSPO is a robust nonlinear control integrated with a nonlinear compensator, which performs better than the SMC even in the presence of external disturbances.
Hamza Khan,Saad Jamshed Abbasi,Muhammad Salman,Min Cheol Lee 제어로봇시스템학회 2022 제어로봇시스템학회 국제학술대회 논문집 Vol.2022 No.11
In this research, a virtual simulator (slave system) of an eight-degrees-of-freedom robot (two-DOF crane, one-DOF prismatic (telescopic mast), and five-DOF robot manipulator) is developed and teleoperated by an external hardware haptic device (master system) for nuclear power plants (NPP) reactor vessel internals (RVI) dismantling operations. For operations such as cutting, the robot end-effector with a laser cutter should maintain a constant distance from the physical wall of RVI. So, a virtual wall near the physical wall is assumed. The end-effector should remain on the virtual wall for optimal cutting which is achieved through force tracking impedance control. In this paper, initially sliding mode control (SMC) was implemented but resulted in chattering in force tracking response. Therefore, super twisting sliding mode control (STSMC)-based force tracking impedance control is designed and implemented for enhanced end-effector force tracking. The control input of the STSMC is composed of a continuous and discrete component. Continuous control input regulates control performance against uncertainties, whereas discrete provides a switching algorithm. STSMC then eliminates the chattering effect and reduces the force tracking error. The performance of SMC-based and STSMC-based impedance control is compared, and the comparison shows that the STSMC-based impedance control provides enhanced performance.
Hamza Khan,Saad Jamshed Abbasi,이민철 대한기계학회 2021 JOURNAL OF MECHANICAL SCIENCE AND TECHNOLOGY Vol.35 No.9
This paper presents a unique optimal torso design selection technique for the dual seven-degree-of-freedom robot arm. This optimal design enhances the robot endeffector's workspace with less operational stress. The selection procedure incorporates the von Mises stress and robot workspace analysis in different robot-torso mounting configurations. The torso design selection strategy includes the von Mises stress calculation numerically and by using SolidWorks static analysis for robot arm considered as bolted-fixed end cantilever beam. Followed by robot end-effector workspace analysis using inverse kinematics, which determines the maximum area covered by manipulated robot end-effector in 2-dimensional (2D) and 3-dimensional (3D) space. Subsequently, introducing a selection function for torso design. This selection function is calculated based on weighting coefficients (priority given to stress and workspace), von Mises stress, and workspace area. The selection technique concludes that the torso design with upper-arm mounting configuration is optimal for current robot application, i.e., assembly.
Dynamics Analysis and Control of 5 DOF Robot Manipulator
Muhammad Salman,Hamza Khan,Saad Jamshed Abbasi,Min Cheol Lee 제어로봇시스템학회 2021 제어로봇시스템학회 국제학술대회 논문집 Vol.2021 No.10
The accurate dynamic model of the robot manipulator is essential for better control performance. Dynamic modelling refers to deriving such equations that explicitly describe the relationship between force and motion in a system. There are several methods to solve for the dynamics of the system. The main concern while doing dynamics is to check its reliability and verification. In this paper, Lagrange Euler (L-E) method is used to dynamically model a five-degrees-of-freedom (DOF) robot manipulator and verified through 3D model of robot in Simulink, simscape multibody toolbox. Followed by the implementation of a proportional-integral-derivative (PID) control with a low pass filter ‘N’ (PIDN) on the derived system. The low pass filter enhances the control performance by eliminating the effect of derivative term’s fluctuations (noise). Furthermore, Ziegler Nichols"s closed-loop tuning method is used to optimally tune the PID control. The derived model and control algorithm simulations have been performed in MATLAB. The simulations results illustrated that the derived model is controllable which indicates the correctness of the derived model.
Estimation Force of Master-Slave for the End Effector of Hydraulic Servo System Using SMCSPO
Karam Dad Kallu,Saad Jamshed Abbasi,Min Cheol Lee 제어로봇시스템학회 2017 제어로봇시스템학회 국제학술대회 논문집 Vol.2017 No.10
In this research a bilateral control method is proposed to find the estimation force of master-slave at the end effector of hydraulic servo system using sliding mode control with sliding perturbation observer (SMCSPO). The sliding perturbation observer (SPO) estimates the reaction force at the end effector of master and slave without using any sensor. Sliding mode control (SMC) is used as bilateral controller for the robust position tracking and control of slave device. A bilateral control strategy in hydraulic servo system provides robust position and force tracking between master and slave. This research experimentally verifies that the slave device can follow the trajectory of the master device using the proposed bilateral control strategy and reaction force estimation method.
햅틱 디바이스를 이용한 Unity 기반 가상 로봇 매니퓰레이터 조작 시스템 구현
이진원,김재형,Hamza Khan,Saad Jamshed Abbasi,이민철 제어·로봇·시스템학회 2022 제어·로봇·시스템학회 논문지 Vol.28 No.8
The digital twin has been attracting attention in various industrial fields, including decommissioning nuclear power plants. In this study, an environment including a multi-axis robot manipulator for dismantling nuclear power plants and reactor vessel internals (RVIs), one of the major nuclear power plant facilities, is implemented virtually using Unity, effects. Integral sliding mode control(ISMC)the robot to the virtual RVIs environmentIdemonstratedwith even if the dynamic model informations were not used. Moreover, the repulsive force is transmitted to the haptic device using the haptic feedback algorithm when the robot manipulator collides with the surrounding environment. .