Presents the table of contents for this issue of the publication.

Presents a listing of the editorial board, board of governors, current staff, committee members, and/or society editors for this issue of the publication.

To possess sufficient compliance while keeping an acceptable stiffness level for manipulation with precision, transoral robotic surgery (TORS) demands a flexible robotic system with variable stiffness (VS) as presented in this paper. In our study, a flexible three-prismatic-universal parallel mechanism employs superelastic nickel–titanium rods to achieve compliant movements beyond the conventional

We introduce a new adaptive control technique based on the second-order strictly negative imaginary (SNI) controller, coupled with the interval type-2 fuzzy self-tuning mechanism. We demonstrate the performance of our controllers in the three control loops of the AR.Drone quadrotor to achieve stable and balanced hover performance in flights with a variable Center-of-Gravity (CoG). To facilitate an

Cable-driven parallel robots (CDPRs) provide fast motions over considerably large workspaces, however, they suffer from undesired vibrations. Kinematically constrained CDPRs (KC-CDPRs) are CDPRs that are designed intentionally to have certain kinematic constraints, which help minimizing undesired modes of motion, enhancing stiffness, and hence establishing robustness to external disturbances. This

Researches for improving the control performance of hydraulic systems in both control accuracy and energy efficiency have never stopped in aerospace and industrial applications. The existence of nonlinearities, uncertainties, and unknown terms in the system dynamics, however, significantly limits the desired performance. To realize improvements by dealing with these problems, an advanced position controller

The article presents a rapid and precision position detection method for permanent magnet synchronous linear motors (PMSLM) based on digital image measurement and line-scanning photography. An exclusive fence pattern is designed as the target image for image measurement method, according to the motion feature of PMSLM. A line scan camera is installed on the mover to record image sequences instantaneously

Discrete-time system inversion for perfect tracking goes at the expense of intersample behavior. The aim of this article is the development of a discrete-time inversion approach that improves continuous-time performance by also addressing the intersample behavior. The approach balances the on-sample and intersample behavior and provides a whole range of new solutions, with stable inversion and multirate

We present the design process of a mechanically decoupled two-dimensional force sensor (M2D) for the implementation of a wearable ground reaction force (GRF) sensing system. The proposed sensor is capable of sensing up to 1000 and $ \pm \text{300 N}$ in the vertical GRF (vGRF) direction and the anterior–posterior GRF (apGRF) direction, respectively, with accuracies of $\text{2.81} \pm \text{0.29}\%$

This article presents the design and validation of a lightweight magnetorheological (MR) clutch, called hybrid magnetorheological (HMR) clutch. The clutch utilizes a hybrid magnetization using an electromagnetic coil and a permanent magnet. The electromagnetic coil can adjust the magnetic field generated by the permanent magnet to a desired value and fully control the transmitted torque. To achieve

The capability of performing animal-like turning action is very important for a biomimetic robot to be used in realistic world. Although the existed biomimetic robots can imitate turning actions of their counterparts, it is still lacking an effective approach to generate bioinspired turning action of small quadruped animals. To solve this problem, we proposed an effective phase-shift-based motion planning

Capture and removal of space debris are challenging in robotic on-orbit servicing activities. A large portion of space debris does not possess any graspable features, which makes the conventional grippers inapplicable. To handle such nongraspable objects, a space robotic capture system is presented. A dual-arm space robot simulator that has the advantages of miniaturization and scalability is designed

Conventional hydraulic dampers reduce vehicle vibration by converting the vibration energy into heat. In addition to wasting energy, the fixed damping characteristics of these dampers cannot adapt to different road conditions. As we know, a suspension with tunable damping provides a more comfortable ride. However, previous works regarding tunable regenerative dampers, which usually consist of a single

For flexure-jointed mechanisms and manipulators, accurate kinematic models typically involve complex nonlinear descriptions of elastic behavior and are ill-suited for real-time control computations. An alternative approach is to use multidimensional function approximation methods, with optimization via online kinematic identification and calibration. In this article, a function interpolation approach

This article presents a new lizard-inspired robot that can maintain its direction of movement via S-shaped lateral body motions during its high-speed bipedal running. For this purpose, a dynamic model and a control scheme for the proposed robot were derived to simulate the S-shaped lateral body motions of a real lizard. Based on simulations using the dynamic model with the proposed control scheme,

Compliant elements, installed in parallel with actuators, potentially contribute to the energy efficiency of legged robots. Nevertheless, finding the most appropriate compliance profile, especially over a reasonable range of locomotion speeds, is still an open topic. This article contributes to the literature on three grounds. First, it proposes optimality conditions for parallel compliance in terms

The nonlinear radial forces relationship regarding phase currents and rotor angle demands a nonlinear control structure for bearingless motors. Most state-of-the-art control algorithms of bearingless motors are based on the assumption of linear current to force/torque relationship, and only the nonlinear relationship to the rotor angle is taken into account. However, in some types of bearingless motors

Impedance control is capable of further flexibly adjusting the driving-point impedance of series elastic actuators (SEAs) in conjunction with impedance reduction by the elastic element. This feature enhances safety and compliance during interaction between humans and robots, in comparison with rigid robots under impedance control or SEAs under position control. In this article, we propose an impedance

This article describes the design of a new type of knee prosthesis called a stance-control swing-assist (SCSA) knee prosthesis. The device is motivated by the recognition that energetically passive stance-controlled microprocessor-controlled knees (SCMPKs) offer many desirable characteristics, such as quiet operation, low weight, high-impedance stance support, and an inertially driven swing-phase motion

In electric railway systems, wear of current collector devices leads to high maintenance cost. To develop a cost reduction methodology, the wear behavior of current collector materials needs to be fully investigated. However, the wear test apparatuses currently in use cannot control the contact force between materials, and the contact force fluctuates. It is difficult to classify accurate conditions

This article proposes a disturbance observer (DOB)-based compliance control strategy for electrohydrostatic actuators (EHAs), particularly those with high gear reductions and long hydraulic pipelines, which could lead to a high performance interactive robot system. EHAs suffer significantly from internal leakage and friction, which hampers the application of existing compliance control methods to EHAs

Common digestive and lung disorders such as stomach problems and pleural emission pose serious difficulties for patients who undergo open surgeries wherein a wirelessly powered swimming microrobot has the potential for minimally invasive missions from diagnosis to drug delivery and surgery. However, remote steering toward an arbitrary destination is yet a challenge to existing microrobots. Here, a

This article presents the design and the experimental validation of a novel 3-degree-of-freedom (DOF) pendulum-like cable-driven robot capable of executing point-to-point motions by leveraging partial feedback linearization control and on-line trajectory planning based on adaptive frequency oscillators (AFOs). Unlike most cable-suspended parallel robots, which rely on at least $n$ actuated cables to

Invasiveness of laparoscopic surgery can be further reduced by using needlescopic instruments which diameter approaches that of a hypodermic needle. However, such needlescopic instruments are limited by the lack of wrist mechanisms with precise and sharp articulating motion. In this article, we present a two-degree-of-freedom wrist mechanism with articulating motion and enhanced kinematic tractability

This article presents a novel piezo-actuated fast steering mirror (FSM) and focuses on the integration of control design and system operation in order to improve its tracking performance for high-speed scanning. The FSM is centered around a membrane-like flexure design and two pairs of stack actuators operated in a push–pull configuration, employing an optical sensor for position measurement. With

The nutation mode is an obstacle to the stability improvement of a magnetic-bearing-supported rotor system with significant gyroscopic effects. This article explores a parameter design method of the filter cross feedback for the nutation mode suppression of asymmetric rotor systems supported by active magnetic bearings (AMBs). First, the coupled multi-input multi-output model of the asymmetric AMB

In this article, the ultrahigh-precision planar motion control problem is investigated for a novel long-stroke multileaf spring based microstage, by considering the cross-axial coupling-induced varying stiffness. In particular, a discrete-time dynamical model with the stress stiffening effect is presented in a parameter varying form, where a discrete-time adaptive extended state observer (ESO) with

A difficult problem of a high-resistance (HR) connection for permanent magnet synchronous motor (PMSM) drives is investigated in this article. The presence of HR affects stator currents in such a way to deviate from their reference currents in the vector-control structure of the drive, which degrades the performance, reliability, and efficiency of the system. Unlike existing schemes, which are limited

Owing to different gravities, the same manned lunar rover shows different acceleration properties on the earth and the moon; therefore, it is of great significance for astronauts to be trained on the earth under the condition of the acceleration properties found on the moon. In this article, a novel acceleration imitation method focused on a single wheel is proposed to obtain equivalent acceleration

The print productivity and medium dimensions of wide-format roll-to-roll printing systems are limited by position errors induced by step-wise medium transportation. The aim of this article is to develop a design framework for multivariable repetitive control (RC), that enables improved productivity and accuracy through continuous media flow printing. The developed technical framework for RC explicitly

This article describes a compact, low-cost, single-board FlexLab/LevLab electromechanical system for use in teaching modeling, dynamics, and control of mechatronic systems. The portable educational platform proposed in this article enables a flipped-lab approach where students can do experimental work outside a dedicated lab facility and so, achieve a better understanding through more extensive hands-on

A high-static–low-dynamic stiffness (HSLDS) vibration isolator based on a tunable nesting-type electromagnetic negative stiffness (NS) mechanism is presented. The stiffness characteristics of the HSLDS system can be tuned by regulating the current in the coil. When the current is zero, the HSLDS system may degenerate into a passive isolator. The distinctive features of this proposed isolation system

This article presents a discrete-time attitude estimation solution based on a cascade of two linear time-varying Kalman filters (KFs). Under mild assumptions, the cascade's first KF resorts to body-fixed measurements of angular velocity and of a constant inertial vector to yield an estimate of Earth's angular velocity. The latter, in addition to all previous measurements, is fed to the second KF to

In many real-world rotary machines, there is an inherent need to attenuate time-varying but position-dependent periodic disturbances. This article proposes an improved repetitive controller, in which a spatial internal model, a spatial low-pass filter, and a frequency alignment are synthesized. The controller is digitally implemented in a uniform time-sampling system. Specifically, a universal internal

A novel method to construct dynamic inversion compensation is proposed for feedforward tracking control. In contrast to common approaches involving parametric system identification followed by inversion synthesis, in this article we apply iterative learning control to track an impulse signal, where the converged control input is directly used to construct the inverse filter. The method is applicable

Twisted string actuation is an actuation concept which uses the twisting motion of strings to convert the rotational motion of a motor into a linear motion. By replacing the heavy, high friction, and high-cost gearheads with light, silent, compliant, and low-cost strings, twisted string actuators (TSAs) can provide powerful tendon-based transmission, making it a unique solution for human–robot interactive

This article presents a novel force sensor to detect the distal force of tendon-sheath mechanisms (TSMs) in flexible endoscopic surgical robots. We propose to measure the compression force on the sheath at the distal end so that the tension force on the tendon, which equals the compression force on the sheath, can be obtained. With this approach, a new force sensor made up of a 1 mm fiber Bragg grating

Cable-driven parallel robots (CDPRs) can provide a high speed and a heavy payload in a large workspace. The main challenge of the CDPRs stems from the dynamic control, in which all the cables must coordinate with each other to remain in tension, and the cable-driven form may lead to model uncertainties. To solve it, the second-order sliding mode (SOSM) is combined with the multicable synchronization

This article presents a distributed curvature sensing and shape reconstruction method based on parallel dual fiber Bragg grating (FBG) arrays for a type of cable-driven soft manipulator with irregular cross sections. The curvature at each measured point can be detected by the differential response of the relevant dual-FBG sensing unit with less interference from the temperature and axial driven force

Reliable health monitoring of mechanical components in aerial robotic systems is crucial to their safe operation. The highly constrained nature of aerial systems requires that such systems operate with a minimum of sensing and computational power. This article proposes a method for the detection and diagnosis of motor/propeller degradation on a multicopter aerial robot. The proposed method works by

Constant-force contact-mode atomic force microscopy (AFM) relies on a feedback control system to regulate the tip–sample interaction during imaging. Due to limitations in actuators and control, the bandwidth of the regulation system is typically small. Therefore, the scan rate is usually limited in order to guarantee a desirable image quality for a constant-rate scan. By adapting the scan rate online

Footstep planning in various three-dimensional environments is formulated as an optimization problem, which is solved using a particle swarm optimi-zation. The objective function for optimization is designed to achieve real-time footstep planning considering arrival at the goal with effective not only foot placements but also walking periods, kinematic constraints: obstacle avoidance and hardware limitations

Control moment gyroscopes (CMG) are widely used as actuators for attitude control of satellites and spacecraft, which requires the controller to fulfill the tracking task of a CMG in a wide operating range, despite its highly coupled nonlinear behavior. A variety of control techniques were proposed for tracking task of the CMG unit, model 750, from Educational Control Products (ECP), but a few accomplished

In this article, a triaxial force and torque sensor is developed and its response is evaluated. The sensor is designed for minimally invasive interventions. The fabrication method of the sensing structure is 3-D printing and the material used is a biocompatible acrylic plastic. Optical fibers are used as sensing elements in this sensor and the working principle is based on the Bragg wavelength shift

A wrist band undergoes torsional loads during twisting motions of the human forearm. In this article, we investigate sensing torsional loads on a silicone cylinder using a wrist band hosting a sensor. We utilize a flexible sensor based on polyvinylidene fluoride, which is a flexible piezoelectric material. The flexible piezoelectric sensor is inserted into a pocket of the wrist band and outputs an

This article proposes a flexible ultrasonic motor that consists of a single metal cube stator with a hole and an elastic elongated coil spring inserted into the hole. When voltages are applied to piezoelectric plates on the stator, the coil spring moves back and forward as a linear slider. The use of the coil spring brings flexibility for the motor and enables a long stroke to access to deeper sites

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Without perfusable vascular networks, 3-D tissues populated with cells cannot maintain a living condition. To construct 3-D tissues, a well-organized vascular network is required. In this article, a method for constructing a hepatic-lobule-like vascular network in a 3-D cellular structure by using magnetic fields is employed. To realize channel networks that mimic the hepatic lobule, steel rods and

Compared to rigid actuators, series elastic actuators (SEAs) offer a potential reduction of motor energy consumption and peak power, though these benefits are highly dependent on the design of the torque-elongation profile of the elastic element. In the case of linear springs, natural dynamics is a traditional method for this design, but it has two major limitations-arbitrary load trajectories are

The knee replacement is one of the most common orthopedic surgical interventions in the United States; however, recent studies have shown up to 20% of patients are dissatisfied with the outcome. One of the key issues to improving these operations is a better understanding of the ligamentous balance during and after surgery. The goal of this work is to investigate the feasibility of embedding piezoelectric

Optical tweezers have enabled important insights into intracellular transport through the investigation of motor proteins, with their ability to manipulate particles at the microscale, affording femto newton force resolution. Its use to realize a constant force clamp has enabled vital insights into the behavior of motor proteins under different load conditions. However, the varying nature of disturbances

In this study, we built and tested a handheld motion-guided micro-forceps system using common-path swept source optical coherence tomography (CP-SSOCT) for highly accurate depth controlled epiretinal membranectomy. A touch sensor and two motors were used in the forceps design to minimize the inherent motion artifact while squeezing the tool handle to actuate the tool and grasp, and to independently

We present a new concept of bearingless slice motor that levitates and rotates a ring-shaped solid rotor. The rotor is made of a semi-hard magnetic material exhibiting magnetic hysteresis, such as D2 steel. The rotor is radially biased with a homopolar permanent-magnetic flux, on which the stator can superimpose 2-pole flux to generate suspension forces. By regulating the suspension forces based on

A widely accepted model of muscle force generation during neuromuscular electrical stimulation (NMES) is a second-order nonlinear musculoskeletal dynamics cascaded to a delayed first-order muscle activation dynamics. However, most nonlinear NMES control methods have either neglected the muscle activation dynamics or used an ad hoc strategies to tackle the muscle activation dynamics, which may not guarantee

This paper presents an iterative Jacobian-based inverse kinematics method for an MRI-guided magnetically-actuated steerable intravascular catheter system. The catheter is directly actuated by magnetic torques generated on a set of current-carrying micro-coils embedded on the catheter tip, by the magnetic field of the magnetic resonance imaging (MRI) scanner. The Jacobian matrix relating changes of

Magnetic Resonance (MR) guided interventional robots have recently been developed for a variety of surgeries, such as biopsy, ablation, and brachytherapy. The actuators and encoders that power and track such robots must be MR-conditional. In this paper, we propose an MR-conditional pneumatic motor with an integrated and custom-built fiber-optical encoder that provides powerful and accurate actuation

Dexterous continuum manipulators (DCMs) have been widely adopted for minimally- and less-invasive surgery. During the operation, these DCMs interact with surrounding anatomy actively or passively. The interaction force will inevitably affect the tip position and shape of DCMs, leading to potentially inaccurate control near critical anatomy. In this paper, we demonstrated a 2D mechanical model for a

Compatibility of mechatronic devices with the MR environment has been a very challenging engineering task. After over a decade of developments, we report the successful translation to clinical trials of our MR Safe robot technology. MrBot is a 6-degree-of-freedom, pneumatically actuated robot for transperineal prostate percutaneous access, built exclusively of electrically nonconductive and nonmagnetic

The inherent compliance of soft fluidic actuators makes them attractive for use in wearable devices and soft robotics. Their flexible nature permits them to be used without traditional rotational or prismatic joints. Without these joints, however, measuring the motion of the actuators is challenging. Actuator-level sensors could improve the performance of continuum robots and robots with compliant

MRI-conditional robotic platforms have proved to be an effective approach for image guided interventions. In this study, a computer-assisted, pneumatically-actuated robot was designed, built, and tested for MRI-guided prostate cancer focal laser ablation (FLA). The robotic manipulator provides two active planar degrees of freedom (DoFs) by using a customized CoreXY frame, and one passive rotational