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This paper reviews the current status of devices for use as exoskeletons for assisting or constraining human movements. Applications include teleoperation and force augmentation to allow people to operate more easily or more efficiently in a variety of situations, including military and emergency service applications.

Manipulators in one form or another have been in existence for many hundreds of years with the design usually motivated by the task to be undertaken. Most often in robots this has led to a simple two fingered claw mechanism which has been adequate for many tasks but when the problem domain includes a varied range of delicate or easily damaged objects, one approach is to emulate those attributes of the human hand which make it such a versatile end‐effector. This paper will study two aspects of manipulator design: the construction of a dextrous hand with multi degree of control prehension, and the actuation systems to drive this hand that will make use of complaint drives to produce a “soft” but highly flexible mechanism to handle delicate products and materials.

This study aims to process multi-agent system with kinds of limitations and constraints, and consider the robot in-hand manipulation as a problem of coordination and cooperation of multi-fingered hand.

A cooperative distributed model predictive control (MPC) algorithm is proposed to perform robot in-hand manipulation.

A cooperative distributed MPC approach is formulated for robot in-hand manipulation problem, which enables address complex limitation and constraint conditions in object motion planning, and realizes tracking trajectory of the object more than tracking position of the object.

This method to implement the moving object task uses the kinematic parameters without the knowledge of dynamic properties of the object. The cooperative distributed MPC scheme is designed to guarantee the movement of the object to a desired position and trajectory at algorithmic level.

This paper aims to discuss, analyze and compare members of a group of actuators with adjustable stiffness, namely: AwAS, AwAS-II and CompACT variable stiffness actuator (VSA) developed at Italian Institute of Technology (IIT).

These actuators are among series type of VSAs where one main motor is dedicated for link positioning and a secondary motor, in series with the first one, regulates the output link stiffness. Regulating the stiffness in this group of actuators is based on the lever concept. Initially, springs were moved along the lever to tune the stiffness while in the later versions stiffness was regulated through relocating pivot point along the lever.

This paper discusses how different mechanisms have been employed in realization of the lever concept in these actuators and what are the advantages and disadvantages of each realization.

Today’s robots are not supposed to be solid, isolated and rigid anymore but rather adaptive, cooperative and compliant entities in our daily life. The new attitudes demand for novel technologies substantially different from those developed for industrial domains both at the hardware and the software levels. This work presents latest three state-of-the-art actuators, developed at IIT, which are great answers to the needs of tomorrow’s robot.

These novel actuators are really ready for commercial exploitation, as they are compact and reliable. The main novelty is based on employing concept of lever mechanism for stiffness regulation. They have been designed and manufactured in a very professional and optimized way.

Many existing trajectory optimization algorithms use parameters like maximum velocity or acceleration to formulate constraints. Due to the ignoring of the quadrotor actual tracking capability, the generated trajectories may not be suitable for tracking control. The purpose of this paper is to design an online adjustment algorithm to improve the overall quadrotor trajectory tracking performance.

The authors propose a reference trajectory resampling layer (RTRL) to dynamically adjust the reference signals according to the current tracking status and future tracking risks. First, the authors design a risk-aware tracking monitor that uses the Frenét tracking errors and the curvature and torsion of the reference trajectory to evaluate tracking risks. Then, the authors propose an online adjusting algorithm by using the time scaling method.

The proposed RTRL is shown to be effective in improving the quadrotor trajectory tracking accuracy by both simulation and experiment results.

Infeasible reference trajectories may cause serious accidents for autonomous quadrotors. The results of this paper can improve the safety of autonomous quadrotor in application.

The purpose of this paper is to study the main landing gear (MLG) mechanism configuration.

Mechanism kinematics and dynamics, stress analysis and sizing of the MLG structural members, and fatigue issues related with the mechanism operation. Spreadsheet solutions were incorporated to this survey to analyze the most conceivable loading situations, and important factors of the mechanism design for an initial evaluation of safety implications.

MLG design approach along with conservative fatigue design factors lies in the area of accepted limits in commercial aircraft industry.

MLG loading associated with landing as well as those associated with ground maneuvers (steering, braking and taxiing) contribute significantly to fatigue damage, along with the stresses induced by manufacturing processes and assembly. The application of FEA methods for the design of the landing gear does not always guarantee a successful approach to the problem solution, if precise analytical solutions are not available in advance.

From the investigation of this incident of fractured struts of the MLG it is confirmed that the reduction in Pintle Housing diameter on the upper part has contributed to the avoidance of damaging the fuel tank above the MLG that would lead to a catastrophic event. On the other hand, the airframe of the SKY-Jet was proved efficient for a belly landing with minor damages to the passengers and heavier damages for the aircraft.

On-line vibration monitoring sensors hooked up to the landing gear strut and Pintle House would greatly enhance safety, without relying in optical surveys in hard to access and inspect areas of the landing gears mechanisms housings.

Analytic methods were adopted and spreadsheet solutions were developed for the MLG main loading situations, along with design issues concerning mechanism kinematics and dynamics, stress analysis and sizing of the MLG structural members, as well as fatigue issues related with the mechanism operation. Spreadsheet solutions were incorporated to this survey to analyze the most conceivable loading situations, and important factors of the mechanism design for an initial evaluation of safety implications.

This paper aims to overcome some of the practical difficulties in assistive control of exoskeletons by developing a new assistive algorithm, called output feedback assistive control (OFAC) method. This method does not require feedbacks from force, electromyography (EMG) or acceleration signals or even their estimated values.

The presented controller uses feedbacks from position and velocity of the output link of series elastic actuators (SEAs) to increase the apparent integral admittance of the assisted systems. Optimal controller coefficients are obtained by maximizing the assistance ratio subjected to constraints of stability, coupled stability and a newly defined comfort measure.

The results confirm the effectiveness of using the inherent properties of SEAs for removing the need for extra controversial sensors in assistive control of 1 degree of freedom (1-DOF) SEA powered exoskeletons. The results also clearly indicate the successful performance of the OFAC method in reducing the external forces required for moving the assisted systems.

As the provided experiments indicate, the proposed method can be easily applied to single DOF compliantly actuated exoskeletons to provide a more reliable assistance with lower costs. This is achieved by removing the need for extra controversial sensors.

This paper proposes a novel assistive controller for SEA-powered exoskeletons with a simple model-free structure and independent of any information about interaction forces and future paths of the system. It also removes the requirement for the extra sensors and transforms the assistive control of the compliantly actuated systems into a simpler problem of position control of the SEA motor.

When it comes to the high accuracy autonomous motion of the mobile robot, it is challenging to effectively control the robot to follow the desired trajectory and transport the payload simultaneously, especially for the cloud robot system. In this paper, a flexible trajectory tracking control scheme is developed via iterative learning control to manage a distributed cloud robot (BIT-6NAZA) under the payload delivery scenarios.

Considering the relationship of six-wheeled independent steering in the BIT-6NAZA robot, an iterative learning controller is implemented for reliable trajectory tracking with the payload transportation. Meanwhile, the stability analysis of the system ensures the effective convergence of the algorithm.

Finally, to evaluate the developed method, some demonstrations, including the different motion models and tracking control, are presented both in simulation and experiment. It can achieve flexible tracking performance of the designed composite algorithm.

This paper provides a feasible method for the trajectory tracking control in the cloud robot system and simultaneously promotes the robot application in practical engineering.

This paper aims to propose an enhanced static model of commercial braided pneumatic artificial muscles (PAMs), which is fully analytical without the need for experimentally determined parameters.

To address the highly nonlinear issues of PAMs, the enhanced model is derived considering the irregular shapes close to their end-fittings, as well as the elastic energy stored in both their braids and rubber bladders. The hysteresis characteristics of PAMs are also explored by analyzing the friction in the crossovers of the interlacing braided strands, together with that between the strands and their surrounding bladders. The isobaric and isometric experiments of a commercial PAM are conducted to demonstrate the enhancement, and the model accuracy is evaluated and compared with some existing models in terms of root mean square errors (RMSEs). Additionally, the proposed model is simplified to facilitate the applications that entail high computational efficiency.

The proposed model agrees well with the experimental results, which indicates its viability to accurately predict the static behaviors. An overall RMSE of 5.24 N shows that the enhanced model is capable of providing higher accuracy than the existing analytical models, while keeping the modeling cost at a minimum.

The proposed model, taking account of non-cylindrical shapes, elastic energy and friction, succeeds in enhancing the static predictions of commercial PAMs. The fully analytical model may accelerate the development of novel PAM-based robots for high-precision control, while giving a deeper understanding of commercial PAMs.

This paper aims to get rid of the traditional basic principle of using the motor as the variable stiffness drive source, simplify the structure of the exoskeleton and reduce the quality of the exoskeleton. This paper proposes to use shape memory alloys (SMA) as the variable stiffness drive source.

In this study, SMA is used to construct the active variable stiffness unit, the Brinson constitutive model is used to establish a dynamic model to control the active variable stiffness unit and the above active variable stiffness unit is used to realize the force control function and construct a lightweight, variable stiffness knee exoskeleton.

The dynamic model constructed in this paper can preliminarily describe the phase transformation process of the active variable stiffness unit and realize the variable stiffness function of the knee exoskeleton. The variable stiffness exoskeleton can effectively reduce the driving error under the high-speed walking condition.

The contribution of this paper is to combine SMAs to construct an active variable stiffness unit, build a dynamic model for controlling the active variable stiffness unit and construct a lightweight, variable stiffness knee exoskeleton.