Power Assistance Research Articles

Development and Fuzzy Sliding Mode Compensation Control of a Power Assist Lower Extremity Exoskeleton

This paper presents a power assist lower extremity exoskeleton and a fuzzy sliding mode compensation controller. First, the mechanical design of this exoskeleton and the control configuration are introduced. Second, the dynamics of lower extremity exoskeleton is analyzed and the sliding mode controller with fuzzy compensation algorithm under uncertainties for exoskeleton joints is proposed. The theoretical proof shows that it is globally stable in the sense of Lyapunov. The experiments indicate that the proposed control scheme is effective; not only it ensures the control accuracy but also is robust to external uncertainties compared with PID control. DOI: http://dx.doi.org/10.5755/j01.mech.24.1.14564

Low-temperature deposition of nanocrystalline Al2O3 films by ion source-assisted magnetron sputtering

In this paper, bipolar pulse reactive magnetron sputtering with ion source assisted deposition method has been utilized for the deposition of nanocrystalline alumina (Al2O3) films at the temperature of 300 °C onto silicon (111) wafers, and cemented carbide substrates. The influence of ion source power, i.e. 0, 1.0, 1.5 and 2.0 kW on the structure, morphology, compressive stress and mechanical properties of the Al2O3 films were investigated. In absence of ion source power assistance, an amorphous Al2O3 film was dominant at deposition temperature of 300 °C. With ion source assisted deposition, the crystalline γ-Al2O3 films were obtained at the same conditions, suggesting an importance of ion source power in crystallinity development of metal oxide films obtained from magnetron sputtering deposition method. Images of surface morphology clearly demonstrated the difference in granular sizes of film surfaces prepared with and without ion source powers. With increasing ion source power from 1.0 to 2.0 kW, the micro-hardness and compressive stress of the films were increased from 7 GPa to 13 GPa and 0.3 GPa to 1.1 GPa, respectively. Results revealed that the reactive magnetron sputtering with the ion source assisted deposition was a simple and effective way to prepare nanocrystalline γ-Al2O3 films at low temperature.

Realization of single joint sensor less power assistance in upper limb exoskeleton robot suits

Realization of single joint sensor less power assistance in upper limb exoskeleton robot suits

Receding Horizon Optimal Control of PHEV with Demanded Torque Estimation Model

This paper proposes a real-time optimization method for the energy management of a plug-in hybrid electric vehicle (PHEV). Focusing on a parallel PHEV and the total energy consumption minimization of on-road driving operation, a suitable control scheme that combining a rule-based block for operation modes decision and a low-level model predictive control (MPC) algorithm to manage the transient operation during power assistance. During the transient operation, a model with time-varying parameter is introduced to generate the driving torque during the predictive horizon. By using the C/GMRES (Continuation/General Minimum Residual) based algorithm, the proposed nonlinear MPC problem is solved efficiently. Simulation results demonstrate the control performance.

Fast Gait Mode Detection and Assistive Torque Control of an Exoskeletal Robotic Orthosis for Walking Assistance

Gait modes, such as level walking, stair ascent/descent, and ramp ascent/descent, show different lower-limb kinematic and kinetic characteristics. Therefore, an accurate detection of these modes is critical for a wearable robot to provide appropriate power assistance. In this paper, a fast gait-mode-detection method based on a body sensor system is proposed. A fuzzy logic algorithm is used to estimate the likelihoods of gait modes in real time. Since the proposed fast gait mode detection makes it possible to select appropriate kinematic and kinetic models for each gait mode, assistive torques required for assisting the human motions can be obtained more naturally and immediately. The proposed methods are all verified by experiments with a lower-limb exoskeletal assistive robot with transparent actuation by series elastic actuators, called the exoskeletal robotic orthosis for walking assistance. Four healthy subjects participated in the experiments. All subjects were asked to perform different gait modes using their normal and simulated abnormal gaits, i.e., blocking the knee joint of one leg during walking. Latency and success rate of gait mode detection are selected as performance criteria. The effectiveness of the proposed gait-mode-based assistive strategy is evaluated using electromyography muscular activities.

Development of Power Assistance System for Transfer Assist Equipment

Development of Power Assistance System for Transfer Assist Equipment

Study on Motion Recognition by Movement-Related Cortical Potential for Elbow and Shoulder Joints Coordinated Movements in Upper-Limb Power Assistance Based on EEG

Study on Motion Recognition by Movement-Related Cortical Potential for Elbow and Shoulder Joints Coordinated Movements in Upper-Limb Power Assistance Based on EEG

Learning of Motion Modification Space in Perception Assist of an Upper Limb Power Assist Robot

Learning of Motion Modification Space in Perception Assist of an Upper Limb Power Assist Robot

空気圧ゴム人工筋を用いた下肢振り上げ支援用パワーアシストウェアの開発

空気圧ゴム人工筋を用いた下肢振り上げ支援用パワーアシストウェアの開発

EFFECTS OF A CLOSED-LOOP PARTIAL POWER ASSISTANCE ON MANUAL WHEELCHAIR LOCOMOTION

Abstract In manual wheelchair locomotion, the large upper extremity loads and the repetitions of the propulsion movement increase the incidence of upper limbs injuries, pain and muscle fatigue. The main goal of this study was to investigate the influence of a closed-loop partial power assistance for manual wheelchairs through predictive simulations of a dynamic four-bar model. The applied control law applied can be seen as an impedance-like control, but it does not require force measurement. The simulation results indicate that this strategy can reduce joint torques without significantly altering the typical kinematic pattern of manual wheelchair locomotion.

Control of Power Assist System for Easy Positioning

Control of Power Assist System for Easy Positioning

Study on Operability Improvement of Power Assist System

Study on Operability Improvement of Power Assist System

A Development of the Rehabilitation System using the Power Assist Hand

A Development of the Rehabilitation System using the Power Assist Hand

空気圧駆動ディスクブレーキ機構を用いた肩部姿勢保持用パワーアシストロボットの開発

空気圧駆動ディスクブレーキ機構を用いた肩部姿勢保持用パワーアシストロボットの開発

Optimization Problems of Power Assist System Using Model Predictive Control with Constraints

Optimization Problems of Power Assist System Using Model Predictive Control with Constraints

A NOVEL CABLE-PULLEY UNDERACTUATED LOWER LIMB EXOSKELETON FOR HUMAN LOAD-CARRYING WALKING

Wearable lower limb exoskeleton has comprehensive applications such as load-carrying augmentation, walking assistance, and rehabilitation training by using many active actuators in the joints to reduce the metabolic cost generally. The traditional fully actuated exoskeleton is bulky and requires large energy consumption, and the passive exoskeleton is difficult to provide effective power assistance. To achieve both small number of actuators and good assisting performance, this paper proposes a cable-pulley underactuated principle-based lower limb exoskeleton. The exoskeleton dynamics was modeled and the human-exoskeleton hybrid model was analyzed via ADAMS and LifeMOD to provide an evaluation method for power assistance. By exploiting the control strategy and utilizing the synergies of torque and power assistance, the hip joint and the knee joint can be actuated by a single cable simultaneously. Moreover, the human-exoskeleton co-simulation method was utilized to verify the assisting performance and control effect. In this simulation, the upper toque peak and power required by human are obviously reduced by power assistance and the joint angle curves without exoskeleton are in accordance with the joint angle curves with exoskeleton almost. In conclusion, the designed exoskeleton is compatible with human motion and feasible to provide effective power assistance in load-carrying walking.

Improvement of Wearable Power Assist Wear for Low Back Support using Pneumatic Actuator

This study focuses on developing a safe, lightweight, power assist device that can be worn by people who like caregivers during lifting or static holding tasks to prevent low back pain (LBP). Therefore in consideration of their flexibility, light weight, and large force to weight ratio we have developed a Wearable Power Assist Wear for caregivers, two types of pneumatic actuators are employed in assisting low back movement for their safety and comfort. The device can be worn directly on the body like normal clothing. Because there is no rigid exoskeleton frame structure, it is lightweight and user friendly. In this paper, we proposed the new type of the wearable power assist wear and improved the controller of control system.

Energy-Efficient Power Assist Control with Periodic Disturbance Observer and Its Experimental Verification Using an Electric Bicycle

Energy-Efficient Power Assist Control with Periodic Disturbance Observer and Its Experimental Verification Using an Electric Bicycle

Evaluation of Labor Burden Reduction Achieved through Wearing an Agricultural Power Assist Suit

Evaluation of Labor Burden Reduction Achieved through Wearing an Agricultural Power Assist Suit

Model-based design validation for advanced energy management strategies for electrified hybrid power trains using innovative vehicle hardware in the loop (VHIL) approach

Hybridization of automotive powertrains by using more than one type of energy converter is considered as an important step towards reducing fuel consumption and air pollutants. Specifically, the development of energy efficient, highly complex, alternative drive-train systems, in which the interactions of different energy converters play an important role, requires new design methods and processes. This paper discusses the inclusion of an alternative hybrid power train into an existing vehicle platform for maximum energy efficiency. The new proposed integrated Vehicle Hardware In-the-loop (VHiL) and Model Based Design (MBD) approach is utilized to evaluate the energy efficiency of electrified powertrain. In VHiL, a complete chassis system becomes an integrated part of the vehicle test bed. A complete conventional Internal Combustion Engine (ICE) powered vehicle is tested in roller bench test for the integration of energy efficient hybrid electric power train modules in closed-loop, real-time, feedback configuration. A model that is a replica of the test vehicle is executed – in real-time- where all hybrid power train modules are included. While the VHiL platform is controlling the signal exchange between the test bed automation software and the vehicle on-board controller, the road load exerted on the driving wheels is manipulated in closed –loop real-time manner in order to reflect all hybrid driving modes including: All Electric Range (AER), Electric Power Assist (EPA) and blended Modes (BM). Upon successful implementation of VHiL, a comparative study between Rule Based (RB) energy management strategy (EMS) and Equivalent Consumption Minimization Strategy (ECMS) to Control Parallel Through-The-Road Hybrid Electric Vehicle (PTTR-HEV) is performed. The study shows that the actual fuel efficiency of the tested vehicle under both control strategies can be used in order to evaluate the effectiveness of energy conversion efficiency of the powertrain system. The fuel consumption of hybridized powertrain is compared with the conventional powertrain equipped in an actual vehicle to help comprehend the degree of efficiency attained by the hybridization. This process is developed in order to enable effective tuning/validation of advanced energy management strategies utilized in hybrid electric powertrain through an evaluation of a complete real chassis system subject to electric hybridization. The VHiL is considered as new evolution for the utilization of vehicle test bed as a predictive mechatronic platform for the development of energy efficient electrified propulsion systems and thus reduce cost and time.