Article
Engineering, Aerospace
Xudong Han, Yongling Fu, Yan Wang, Mingkang Wang, Deming Zhu
Summary: This research proposes a dynamic surface-based adaptive active disturbance rejection control (DSAADRC) method for the electrohydrostatic actuator (EHA). The method estimates unknown parameters, compensates for uncertain disturbances, and handles non-matching disturbances using a combination of adaptive law, disturbance estimation, and dynamic surface method. The Lyapunov stability analysis demonstrates that the method achieves position tracking accuracy under time-varying external disturbances, and simulation and experiment comparison shows its stronger anti-disturbance capability compared to other control strategies.
Article
Engineering, Mechanical
Linjie Li, Mingkang Wang, Rongrong Yang, Yongling Fu, Deming Zhu
Summary: An adaptive damping variable sliding mode controller is proposed in this study to address the nonlinearity and parametric uncertainties of electrohydrostatic actuators. The controller integrates variable-damping sliding mode control, parametric adaptation, and an extended state observer to effectively capture and compensate for parametric uncertainties, reduce system uncertainties, and estimate and compensate for disturbances with a fast and stable response. Experimental results demonstrate that the controller outperforms widely used methods in overshoot suppression, settling time, and tracking accuracy.
Article
Automation & Control Systems
Wei Qian, Junbei Liao, Linjun Lu, Letian Ai, Miao Li, Xiaohui Xiao, Zhao Guo
Summary: This article introduces a lightweight, comfortable, cable-driven, and compliant upper limb rehabilitation exoskeleton robot. It features modular series elastic actuators that provide controlled torque for each active joint, with Bowden cables transferring torque to distal joints. The system has a large range of motion and can provide accurate torque control for stroke patients' requirements. A comprehensive rehabilitation strategy, including robot-in-charge mode and human-in-charge mode, was developed for different recovery stages. Finally, a virtual reality training system was developed to assist subjects in efficient upper limb rehabilitation.
IEEE-ASME TRANSACTIONS ON MECHATRONICS
(2023)
Article
Chemistry, Analytical
Tianshuo Wang, Tianjiao Zheng, Sikai Zhao, Dongbao Sui, Jie Zhao, Yanhe Zhu
Summary: In this work, a series-parallel elastic actuator (SPEA) is designed to meet the demanding requirements of a weight-bearing exoskeleton robot called PALExo. The actuator consists of an electric cylinder, gas spring, and series elastic module (SEM) to provide sufficient force output with high compliance and adaptability to different stiffness requirements. The performance of the force controller is verified by experiments, demonstrating good adaptability to varying SEM stiffness.
Article
Robotics
Biao Liu, YouWei Liu, Zikang Zhou, Longhan Xie
Summary: The study focuses on assisting knee joint movements using a soft exoskeleton robot to address inadequate knee flexion due to muscle weakness post-stroke. By employing a novel structure and dual-motor driving method, successful knee flexion function was achieved, and the feasibility and efficacy of the method were verified through simulations and experiments.
Article
Engineering, Mechanical
Mingkang Wang, Yan Wang, Rongrong Yang, Yongling Fu, Deming Zhu
Summary: This study introduces a sliding mode control strategy with a damping variable for EHA operation, using a novel sliding mode controller and ESO, with simulations and experiments showing strong evidence of good dynamic performance compared to widely used control strategies.
Review
Computer Science, Artificial Intelligence
Gilbert Masengo, Xiaodong Zhang, Runlin Dong, Ahmad B. Alhassan, Khaled Hamza, Emmanuel Mudaheranwa
Summary: Effective control of an exoskeleton robot using a human-robot interface is crucial, and this review examines the recent developments and problems in exoskeleton control systems, with a focus on the last few years. The review also discusses the trends and challenges of cooperative control, particularly multi-information fusion.
FRONTIERS IN NEUROROBOTICS
(2023)
Article
Materials Science, Multidisciplinary
Chenchu Zhang, Heng Zhang, Renfei Chen, Linhan Zhao, Hao Wu, Chaowei Wang, Ying Hu
Summary: Inspired by shrimps, a method combining hard exoskeleton structure and soft stimuli-responsive actuator is proposed, which can protect the material, change the movement strategy, and achieve motion control.
ADVANCED MATERIALS TECHNOLOGIES
(2022)
Article
Engineering, Mechanical
Pawel Herbin, Miroslaw Pajor
Summary: The article introduces the structure, control system, and joint drive system of the upper limb exoskeleton; utilizes Bowden cable transmission and serial elastic actuator concept to control drive torque; presents joint control methods minimizing friction impact and torque estimation methods based on the exoskeleton dynamics model.
MECHANISM AND MACHINE THEORY
(2021)
Article
Automation & Control Systems
Brahim Brahmi, Tanvir Ahmed, Ibrahim El Bojairami, Asif Al Zubayer Swapnil, Md Assad-Uz-Zaman, Katie Schultz, Erin McGonigle, Mohammad Habibur Rahman
Summary: This article presents a novel robust control strategy based on variables transformation for nonlinear dynamic systems. The proposed control technique, which integrates differential flatness and geometrical transformation, is applied to a smart robotic exoskeleton for upper limb rehabilitation therapy. The control scheme ensures continuous enhanced trajectory tracking and robustness during rehabilitation exercises, and all signals are bounded using Lyapunov theory in the closed-loop form.
IEEE-ASME TRANSACTIONS ON MECHATRONICS
(2022)
Article
Engineering, Aerospace
Yan Wang, Mingkang Wang, Jian Fu, Yongling Fu
Summary: This study proposes a novel electrohydrostatic actuator (EHA) system with a constant-torque variable-displacement pump (CTVDP) structure, aiming to improve system performance by reducing the maximum motor torque and the volume and weight of the servo motor. An adaptive backstepping control algorithm is also proposed to enhance position-tracking performance. Numerical simulations demonstrate that the system with CTVDP structure exhibits robustness against load impact, pump displacement variation, and parameter uncertainty, while reducing the maximum motor torque.
JOURNAL OF AEROSPACE ENGINEERING
(2022)
Article
Biotechnology & Applied Microbiology
Xueshan Gao, Pengfei Zhang, Xuefeng Peng, Jianbo Zhao, Kaiyuan Liu, Mingda Miao, Peng Zhao, Dingji Luo, Yige Li
Summary: This paper proposes an adaptive particle swarm optimization admittance control algorithm (APSOAC) to overcome the problem of particle swarm falling into local optimal points. The proposed algorithm adjusts the stiffness and damping parameters of the admittance control online and adaptively plans the patient's desired gait profile. In addition, a dual RBF neural network adaptive sliding mode controller (DRNNASMC) is proposed to track the gait profile, compensate for frictional forces and external perturbations, and perform stability analysis based on the Lyapunov theory.
FRONTIERS IN BIOENGINEERING AND BIOTECHNOLOGY
(2023)
Article
Automation & Control Systems
Jiyuan Song, Aibin Zhu, Yao Tu, Xiaodong Zhang, Guangzhong Cao
Summary: This research introduces a novel crank-slider series elastic actuator (CS-SEA) for lower-limb exoskeleton joint module. Compared to traditional designs, it has better torque effect and transparency. The precise force control performance is verified through experiments, and it is successfully applied in a knee exoskeleton prototype.
IEEE-ASME TRANSACTIONS ON MECHATRONICS
(2023)
Article
Automation & Control Systems
Xiaoxia Han, Zhixiang Chen, Yongbao Feng, Jian Xie, Xiaoling Wei, Liejiang Wei
Summary: This paper proposes a cascade active disturbance rejection control method for single-rod electrohydrostatic actuators with parametric uncertainties and severe external disturbances. The proposed method can effectively estimate and compensate for uncertainties and theoretically ensure accurate position tracking.
ASIAN JOURNAL OF CONTROL
(2023)
Article
Chemistry, Analytical
Zhipeng Wang, Chifu Yang, Zhen Ding, Tao Yang, Hao Guo, Feng Jiang, Bowen Tian
Summary: The advantages of Bowden cable-based exoskeletons lie in their lightweight and flexible nature, making them convenient for human assistance. However, their performance is restricted by the exoskeleton's structure and human-exoskeleton interaction. In this study, control methods including disturbance observer, human-exoskeleton interaction feedforward model, and angle prediction using encoder are proposed to compensate for disturbances and limitations, thus improving the accuracy of assistance.
Article
Energy & Fuels
Pauli Mustalahti, Jouni Mattila
Summary: Series elastic actuators (SEAs) are commonly used in torque-controlled electric lightweight arm applications. They provide high force fidelity, shock tolerance, and force sensing. Designing controllers for hydraulic SEAs (HSEAs) is challenging, but a full state feedback controller and a position-based impedance controller have been proposed to handle the highly nonlinear dynamics behavior and control the HSEA system effectively.
Article
Energy & Fuels
Teemu Mononen, Jouni Mattila
Summary: This article introduces a flow-bounded velocity controller that enables accurate automatic grading with online velocity scaling. Compared to constant velocity driving, this controller significantly reduces errors in blade positioning, reduces completion time, saves fuel, and maintains control performance.
Article
Automation & Control Systems
Jukka-Pekka Humaloja, Janne Koivumaki, Lassi Paunonen, Jouni Mattila
Summary: This article incorporates the design of a velocity observer into the virtual decomposition control strategy of an N-degree of freedom open-chain robotic manipulator. The proposed design decomposes the manipulator into subsystems, allowing for decentralized controller-observer implementation. The design achieves semi-global exponential convergence of the tracking error.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2022)
Article
Automation & Control Systems
Santeri Lampinen, Janne Koivumaki, Wen-Hong Zhu, Jouni Mattila
Summary: This study presents a high-precision bilateral teleoperation control for a dissimilar master-slave system, incorporating a novel subsystem-dynamics-based control method. Experimental results demonstrate exceptional tracking performance of the proposed system.
IEEE TRANSACTIONS ON CONTROL SYSTEMS TECHNOLOGY
(2022)
Article
Engineering, Mechanical
Goran R. Petrovic, Jouni Mattila
Summary: This paper proposes a new modelling approach for a heavy-duty manipulator with parallel-serial structures. The expressions for actuator forces are derived and the actuator pressure dynamics are considered. A control law based on the new model is formulated in the virtual decomposition control process.
MECHANISM AND MACHINE THEORY
(2022)
Article
Automation & Control Systems
Bobo Helian, Pauli Mustalahti, Jouni Mattila, Zheng Chen, Bin Yao
Summary: This study proposes an adaptive robust pressure control strategy for variable displacement axial piston pumps (VDAPPs), which deals with dynamic nonlinearities and parametric uncertainties to achieve accurate pressure tracking. The proposed controller shows higher pressure tracking accuracy and great capability in handling dynamic nonlinearities, uncertainties, and time-varying disturbances.
Article
Engineering, Mechanical
Pekka Maenpaa, Jouni Mattila
Summary: This paper discusses the path planning and path-following control for a four-wheel drive, steer-articulated boom lift driven by hydraulic actuators. The environment is assumed to be both static and known. The path planning is done in two phases, with the first phase finding a crude, collision-free path considering the vehicle dimensions, and the path is then smoothed with a path-smoothing algorithm to meet the kinematic and dynamic constraints imposed by the vehicle and its actuators. The selection of the path-smoothing algorithm is done through simulations, and the results are used to verify the feasibility of the path planner in heavy-duty, four-wheel-steered field robots with hydraulic actuators and high inertia.
INTERNATIONAL JOURNAL OF FLUID POWER
(2023)
Article
Automation & Control Systems
Fengqi Zhou, Hao Liu, Pengfei Zhang, Xiaoping Ouyang, Lilin Xu, Yibo Ge, Yeming Yao, Huayong Yang
Summary: This article proposes a solution to the flow mismatch, strong nonlinearity, and complex disturbance challenges in electro-hydrostatic actuator (EHA) control. It introduces a three-port piston pump to replace the traditional two-port piston pump in EHA, and designs an extended state observer and a nonlinear disturbance observer to estimate matched and mismatched disturbances. The virtual decomposition control method is adopted to achieve high-precision nonlinear control of EHA.
IEEE-ASME TRANSACTIONS ON MECHATRONICS
(2023)
Article
Robotics
Mahdi Hejrati, Jouni Mattila
Summary: This study proposes a subsystem-based adaptive impedance control method for a 7-degree-of-freedom haptic exoskeleton, which ensures stability and allows rendering a wide range of virtual environments. The presented controller decomposes the system into subsystems and designs the controller at the subsystem level. It is proven to be stable in the presence of contact with a virtual environment and human arm force, and the Z-width of the haptic exoskeleton is improved by exploiting varying virtual mass element.
IEEE ROBOTICS AND AUTOMATION LETTERS
(2023)
Article
Automation & Control Systems
Min Cheng, Linan Li, Ruqi Ding, Bing Xu, Pei Jiang, Jouni Mattila
Summary: A real-time redundancy resolution method is proposed for flow optimization, considering the primary trajectory tracking task and the hard joint constraints. All joint constraints are involved in a velocity polytope, and a time-efficient polytope vertex solver is designed to obtain the velocity boundaries. The redundancy resolution method for flow optimization is then presented by calculating the intersection of the velocity polytope and the null space of the Jacobian matrix. Comparison tests on a 3-DOF planar hydraulic redundant manipulator show that the proposed method has the least flow consumption and smallest trajectory errors while meeting all hard constraints.
IEEE-ASME TRANSACTIONS ON MECHATRONICS
(2023)
Article
Automation & Control Systems
Janne Koivumaki, Jukka-Pekka Humaloja, Lassi Paunonen, Wen-Hong Zhu, Jouni Mattila
Summary: This study proposes an adaptive subsystem-based control (SBC) method for systematic and straightforward nonlinear control of nth-order strict-feedback form (SFF) systems. By decomposing the SFF system into subsystems, a stability connector is created to address dynamic interactions between the subsystems. This enables modular control design with global asymptotic stability and avoids excessive complexity when dealing with high-order systems.
IEEE TRANSACTIONS ON AUTOMATIC CONTROL
(2023)
Proceedings Paper
Automation & Control Systems
Mohammad Bahari, Alvaro Paz, Andrew S. Habib, Jouni Mattila
Summary: With emission reduction targets in mind, electrification has become the focus in vehicle mountable equipment. This study investigates the energy conversion processes and loss in electromechanical linear actuators, and evaluates the performance of the system through trajectory optimization.
2023 IEEE 97TH VEHICULAR TECHNOLOGY CONFERENCE, VTC2023-SPRING
(2023)
