This paper presents a new method of disturbance observer-based control (DOBC) for multi-input-multi-output (MIMO) highly-coupled unstable systems. In contrast to the current input–output approach for stable single-input-single-output (SISO) systems, the Youla parameterization of stabilizing controllers by full order state observer (FOSO) feedback control is shown more appropriate for general MIMO systems

A microsurgery-specific haptic interface with articulated structure, possessing 3 active, 4 passive and 3 supplementary degrees of freedom (DOFs), was designed and developed. The system includes a 3-DOF active serial linkage design, mimicking the human upper extremity. It is combined with a microsurgery-specific end-effector, comprised of a 3-DOF passive gimbal mechanism and a 1-DOF passive exchangeable

A Hydraulic Variable Valve Actuation (HVVA) system is studied in this work, it can continuously adjust engine valve timing and lift at any engine speeds by using a hydraulic actuation system. A detailed co-simulation model is built to reveal relationship between hydraulic pressure, engine valve lift and power consumption, it has taken flow rate, fluid property and pressure drop into consideration.

Acoustic-based techniques are the standard for localization and communication in underwater environments, but due to the challenges associated with this medium, it is becoming increasingly popular to find alternatives such as using optics. In our prior work we developed an LED-based Simultaneous Localization and Communication (SLAC) approach that used the bearing angles, needed for establishing optical

Colonoscopy is a common procedure to perform advanced therapies such as Endoscopic Submucosal Dissection (ESD), which allows for greater diagnostic specificity and sensitivity compared to other types of examination. Nevertheless, since the colonoscope can cause patient discomfort or pain due to improper manipulation, it is quite challenging for endoscopists who need to develop the necessary skills

This paper presents a methodology for height and yaw angle control of a quadrotor that transports an unknown constant load added before the flight. Based on measurements from the onboard sensors, estimates of inertial parameters – mass and z-axis inertia – and state variables – vertical position, velocity, yaw angle and rate – are provided resorting to Multiple-Model Adaptive Estimators. The number

Research on the robustness of clutch engagement control is attracting considerable interest because of its wide applications in advanced powertrains. Internal model control (IMC) is advantageous because it can handle model errors and external disturbances with light computational loads. However, during clutch engagement, two control inputs (engine output torque and clutch transmitted torque) and two

The “Next Generation Train” (NGT) is a double-deck high speed train concept in light-weight design that has been established as a technical and project framework in which the German Aerospace Center gathers its long-term railway vehicle research. To reduce wheel and rail wear and to enhance the passenger capacity, a mechatronic running gear with independently rotating wheels (IRW) is a key vehicle

As the core of Industry 4.0, the intelligent manufacturing technology requires robotic arms to be networked, customized and flexible. Traditional industrial robots have a large number of electrical cables. The end effectors cannot be easily replaced. In this paper, a reconfigurable modular arm with quick replacement of tools and its neural adaptive control system are developed. It consists of an anthropomorphic

Virtual process planning offers advantages in terms of predicting servo and contouring errors ahead of time, and taking corrective action by modifying the program or CNC parameters. Successful application of virtual process planning requires accurate models that capture the dynamics of feed drives. Identification of such models is typically time consuming. This paper presents a pole search method used

Powered ankle-foot orthosis (PAFO) is a field of wearable robotics that improves the lives of people of old age or with physical impairments by aiding in the wearer's ankle joint movements. Most of the PAFOs developed thus far offer only one degree-of-freedom (dof), which uses the talocrural joint alone as the axis of rotation, where the emphasis is on moving forward. However, because this type of

In this study, the effects of contact forces on the rollers of a mecanum wheeled robot are investigated. Modeling structures are constructed for the cases of single and multiple contact forces. A simulation environment is developed to examine these two cases. A theoretical model is proposed in order to reflect reality in the simulation environment. It is shown that single contact force assumption generates

Collaborative tracking control involves two or more subsystems working together to perform a global objective, and is increasingly used within a diverse range of applications. Decentralised iterative learning control schemes have demonstrated highly accurate collaborative tracking by using past experience gained over repeated attempts at the task. However they impose highly restrictive constraints

Underactuated robotic systems have become an important research topic aiming at significant improvement of the behavioural performance and energy efficiency. Adopting some bio-inspired ideas and properties, the self-organisation and main tasks of the robotic systems can be achieved by coordination of the subsystems and dynamic interaction with the environment. Conversely, biological systems achieve

This work presents the design, simulation, control and experimental result of an optical scanning laser sensor for 3D imaging. The system design satisfies the Scheimpflug condition even though only the illumination path is scanned by a compact fast steering mirror (FSM). To reconstruct the surface profile from measured quantities and model parameters, geometrical relations are used. The influence of

In this paper, a new simple tracking control scheme is presented for quadrotor systems with uncertain dynamics. It precludes the necessity for prohibitive analytic computation of the derivatives of the desired (virtual) attitude that is typically employed in controlling quadrotor systems. Moreover, this control scheme is approximation-free in the sense that it does not incorporate any adaptive laws

This study presents an event driven automatic controller to regulate the movement of a mobile lower limb active orthosis (LLAO) triggered with the information obtained from electromyographic (EMG) signals, which are captured from the user’s triceps and biceps muscles. The proposed controller has an output feedback realization including a velocity estimator algorithm based on a high order sliding mode

Inversion-based feedforward control is a basic method of tracking controls. The aim of this paper is to design MIMO multirate feedforward controller that improves continuous-time tracking performance in MIMO LTI systems considering not only on-sample but also intersample behavior. Several types of MIMO multirate feedforward controllers are designed and evaluated in terms of the 2-norm of the control

The thermo-mechanical effects in machine tools (MTs) are represented by complex models since they may produce non-linear distortions overtime, impacting significantly on the machining accuracy. This paper aims to model the deformation of CFRP (Carbon-Fiber-Reinforced-Polymers) structures using data-driven schemes to predict and compensate the structural thermo-mechanical behavior. A novel study is

Thermally-induced disturbances limit the beam quality of high-power lasers and evoke set point-dependent disturbances. As a result, the beam parameters and the laser’s output power of conventional high-power lasers cannot be chosen independently. To overcome this issue, we suggest spherical intra-cavity mirrors as actuators to dynamically compensate the impact of thermal lensing within the framework

Frequency Response Functions (FRFs) are essential in mechatronic systems and its application ranges from system design and validation to controller design and diagnostics. The aim of this paper is to optimally design experiments for FRF identification of multivariable motion systems subject to element-wise power constraints. A multivariable excitation design framework is established that explicitly

Axial piston motors and pumps are core components in many hydromechanical systems as for instance the powertrain of wheel loader vehicles. The optimal performance of the individual components as well as the entire powertrain requires a fast and exact control of both the motor’s swivel angle as well as the pressure difference over the pump by means of the currently available information and despite

X-in-the-loop (XiL) enables testing of a hardware prototype considering the remaining system by emulation of the system behavior to support early validation in the context of frontloading. To test a scaled prototype integrated in a remaining system, an adjustment of the rotational quantities between the prototype and remaining system is necessary. It is currently unclear, how scaling factors based

In this study, we present a method of nonlinear identification and optimal feedforward friction compensation for an industrial single degree of freedom motion platform. The platform has precise reference tracking requirements while suffering from nonlinear dynamic effects, such as friction and backlash in the driveline. To eliminate nonlinear dynamic effects and achieve precise reference tracking,

Ultra-high vacuum chemical vapor deposition is a thin film deposition process that features excellent film purity, but is sensitive to the processing variations (such as, the precursors and their dispensers, the reactor’s initial condition, etc.). In this paper, we present the design of a ultra-high vacuum chemical vapor deposition reactor with in situ partial pressure atomic absorption spectroscopy

The active rejection of harmonic disturbances is of great importance in many industrial applications. For instance, transverse vibrations of steel strips in hot-dip galvanizing lines entail an inhomogeneous zinc coating of the final product. Controlling the vibrations of these steel strips is particularly complicated because their direct measurement at the relevant location is not available. More specifically

Accurate phase detection and control of nonlinear resonant micro-opto-electro-mechanical system (MOEMS) mirrors are crucial to achieve stable scanning motions and high resolution imaging as needed in precision applications. This paper proposes a precise phase detection method for an electrostatic actuated MOEMS mirror and a novel digital phase locked loop (PLL) that uses an asynchronous logic for high

Data-driven feedforward tuning enables high performance for control systems that perform varying tasks by using past measurement data. The aim of this paper is to develop an approach for data-driven feedforward tuning that achieves high accuracy and at the same time is computationally inexpensive. A linear parametrization is employed that enables parsimonious modeling of inverse systems for feedforward

In this study, a novel adaptive interval type-2 fuzzy controller (AIT2FC) is used for a single-wheel vehicle (SWV) control problem. A control technique for use by a person riding on an SWV that enables real-world balance control of electric unicycles is proposed. The proposed SWV can keep balance and move around. Moreover, it can also stand up stably in any position when a person rides on it without

Recently, there has been a growing demand for electro-hydraulic systems that can offer both high control performance and high energy efficiency. Traditionally, high performance is achieved using expensive high-bandwidth servo valve-controlled units. However, the inevitable throttling losses that occur in such systems severely decrease their energy efficiency. For a higher energy efficiency, pump-controlled

Robots have long been part of production lines and, since they are widely used in a variety of applications, they have become a mass product. Yet, their integration into production is costly due to the necessity of skilled engineers programming them. The goal of this article is to reduce these costs via a programming by demonstration approach, allowing unskilled workers to complete the task of said

Calling out using sound is a typical means of meeting or knowing where you are with reference to the sound generating source. In acoustic homing, the autonomous vehicle moves to the (home) location where the sound source is placed. This paper attempts to provide a practical solution for acoustic homing of a small-sized autonomous underwater vehicle (AUV). The AUV maneuvers can be easily decoupled in

The greatest limitation for an amputee subject who uses a prosthesis having no sensory feedback is the difficulty to manage unexpected events in an autonomous way. In grasp and manipulation tasks, the possibility of object slippage is high. For this reason, it is necessary to detect the beginning of the slippage and provide the control with a fast contrast action. In this work, a touch-and-slippage

Thermally induced deformations are becoming increasingly important for the control performance of precision motion systems. The aim of this paper is to identify the underlying thermal dynamics in view of precision motion control. Identifying thermal systems is challenging due to strong transients, large time constants, excitation signal limitations, large environmental disturbances, and temperature

With the expansion of the self-balancing personal mobility (SBPM) market, an increasing number of accidents have been reported in recent years, while the relevant safety regulations have not been established yet. Safety and dynamic stability of the SBPM is critical for their operation, and they must be evaluated for them. SBPMs are operated by a human rider even for the evaluation tests, so the objectivity

This paper aims to develop an approach for the reconfiguration of a parallel kinematic manipulator (PKM) with four degrees of freedom (DoF) designed to tackle tasks of diagnosis and rehabilitation in an injured knee. The original layout of the 4-DoF manipulator presents Type-II singular configurations within its workspace. Thus, we proposed to reconfigure the manipulator for avoiding such singularities

Tendon-driven actuation allows for light and compact manipulator designs with enhanced safety features. One of the key challenges in model-based control of tendon-driven robots is the increased complexity of the dynamic model, due in large part to difficult-to-model behavior like nonlinear dynamic deformation and friction at the tendons. While purely data-driven modeling approaches, e.g., neural networks

A disturbance observer-based-dynamic load-torque compensator for current-controlled DC-drives, as joint actuator of assistive exoskeletons, has been recently proposed. It has been shown that this compensator can effectively linearize and decouple the coupled nonlinear dynamics of the human-exoskeleton system, by more effectively compensating the associated nonlinear load-torques of the exoskeleton

Multi-motor driving servomechanisms are widely used in modern industry for high-performance applications involving synchronized control of position, speed, acceleration and deceleration. Several synchronous control schemes have been developed to achieve good speed or position tracking regardless of various uncertainties and load torque perturbations. However, these solutions have some disadvantages

In this paper, a novel range-based control algorithm for dual-stage nanopositioners is studied. Dual-stage nanopositioning systems have the powerful ability to achieve high-speed and long-range positioning by coupling a short-range, high-speed actuator with a long-range, low-speed actuator. One of the drawbacks of currently implemented control algorithms is that they tend to determine control allocation

In this paper, a flexure-based piezoelectric actuated microgripper is presented for high precision micro/nano manipulation tasks. A new design of microgripper based on a three-stage displacement amplification mechanism is utilized to magnify the piezoelectric actuator displacement. A bridge-type mechanism with a two-sided output port is serially connected with two consecutive lever mechanisms. The

A robotic system can consist of a single or multiple agents with a fixed or mobile base, with full or under-actuation, and possibly redundancy. Collision avoidance is a crucial task for any robotic system and is necessary to ensure safe operation. In this paper, we use a set-based approach to ensure collision avoidance as a high-priority task of a robotic system while simultaneously defining one or

This paper describes a research activity concerning the design and the development of an energy harvesting system integrated in a pneumatic spring for railway application to recover otherwise wasted energy sources from the train suspension vibration. The final scope of this research is to harvest energy and create a self-powered smart component capable of supplying useful information for the monitoring

Wheel-legged robots operating on the ground experience real-time interactions with the complex unknown terrain, which may lead to tilting of the whole body and instability if no regulated effort is made. Maintaining a horizontal posture of the whole body with changes in the terrain geometry via impedance control (IC) that is widely used in many fields is desirable to be realized. However, because the

Most of the existing (BLDCM) brushless dc motor drive systems are designed with the traditional drive scheme for long-time operation. For short-time and heavy-duty applications, there are problems of energy consumption, large volume, heavyweight and high-cost. In this paper, a new short-time high-overload BLDCM drive system based on "electronic flywheel" and time-division switching control is proposed

A vehicle-manipulator system (VMS) is a class of mobile robots characterised by their ability to carry or be a robotic arm and therefore also manipulate objects. The VMS class includes vehicles with a robotic manipulator, free-floating space robots, aerial manipulators and underwater vehicle-manipulator systems (UVMSs). All of these systems need a kinematic controller to solve the kinematic redundancy

Four-bar mechanisms have increased their use in current applications from industrial to rehabilitation systems. These applications become more demanding over time, and the control systems are required to provide them higher accuracy, lower energy consumption, and an extended lifetime, among other conflicting features. In addition to the previously mentioned demands, four-bar mechanisms have highly

This research focuses on the development of an electric bicycle robot which balances itself while moving at a constant forward speed. The bicycle robot is balanced by applying a pendulum mass moving together with heading steering to share the balancing load. The nonlinear dynamics model of a bicycle along with a pendulum is derived from the Euler-Lagrange equation of motion and nonholonomic constraints

In order to increase the mobility and dynamic agility of a two-wheeled self-balancing vehicle, a dynamic posture control strategy for the initial state transition is proposed in terms of a well-planned nonlinear reference trajectory. The dynamic trajectory planning for the underactuatedmobile inverted pendulum is conducted by solving a two-point boundary value problem with the constraint equation of

Position based visual servoing is a widely adopted tool in robotics and automation. While the extended Kalman filter (EKF) has been proposed as an effective technique for this, it requires accurate noise covariance matrices to render desirable performance. Although numerous techniques for updating or estimating the covariance matrices have been developed in the literature, many of these suffer from

Modern industrial production requires fast and automated quality control using state-of-the-art surface metrology sensors embedded in fast high-precision measuring machines. In order to achieve both fast and precise positioning, active control systems with model-based compensation of dynamic positioning errors due to increased acceleration forces can be applied. However, these active control systems

Characterized by high power-to-weight ratio, modularity and energy efficiency, electro-hydrostatic actuators (EHAs) have been successfully applied to aircrafts and submarines, where high precision and repeatability are in high demand. The position tracking performance, however, can be inevitably affected by parametric uncertainties and uncertain nonlinearities. Model inaccuracy or system variations

Brake-by-wire (BBW) systems are electronically regulated actuators, which are capable of producing a desired braking torque to the vehicle's wheel. This paper focuses on the motor-type electro-hydraulic brake (EHB) system: an electric motor driven rotational-to-linear reducing mechanism that directly pushes the master cylinder to generate hydraulic pressure. A simple and practicable controller is developed

By employing a couple of columnar magnets with a specific arrangement, a negative stiffness magnetic spring (NSMS) is designed, modelled and then experimentally validated in this paper. Such a magnetic spring with negative stiffness can be used for a semi-active seat suspension to achieve vibration reduction on vehicle drivers. Extensive simulation analysis and experimental validation based on static

Owing to numerous advantages to patients, percutaneous intervention has become a popular research topic in recent decades. To improve trajectory following accuracy, many robotic steering systems have been developed using various advanced control algorithms. To overcome the complicated modeling procedures, this study proposed a three-dimensional (3D) feedback control method based on fuzzy logic for

In this paper we present a spherical soft robotic arm made from fabric. The inflatable arm has a small mass and is pneumatically actuated. A configuration is employed with only three actuators controlling the two rotational degrees of freedom of a spherical joint. This differs from the commonly employed antagonistic pairs, including four actuators for two degrees of freedom. The fabrication procedure

In desert zones, a continuous cleaning activity of photovoltaic panels in solar plants is required since the deposition of both airborne dust and sand after a storm can reduce their efficiency up to 80%. Manual cleaning of the photovoltaic panels in dry areas is costly, cannot make use of water and workers must be employed several times in a month, often under extreme environmental conditions. For

This paper presents a trajectory optimization framework for planning dynamic legged locomotion based on a robot’s centroidal momentum (CM), which is the aggregation of all the links’ momenta at the robot’s Center of Mass (CoM). This new framework is built around CM dynamic model driven by Ground Reaction Forces (GRFs) parameterized with Bézier polynomials. Due to the simple form of CM dynamics, the