Motivated by the need to incorporate human spine mechanics into the design loop of wearable spine assistive devices, this article presents a spine-equivalent beam (SEB) model for analyzing kinematics and mechanics of a human spine in sagittal standing flexion. The model is capable of handling loads resulted from the head, arms, external payload, torso weight, and back muscle effects, and it also handles

Reducing the input data of tactile sensory systems brings a large degree of freedom to real-world implementations from the perspectives of bandwidth and computational complexity. For this, in this letter, we suggest efficient active-cell formations with a high classification accuracy of tactile materials. By revealing that averaged Kullback–Leibler-divergence and common frequency component power to

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This article develops and experimentally validates a distributed predictive control algorithm for closed-loop control of inkjet 3-D printing to handle constraints, e.g., droplet volume bounds, as well as the large-scale nature of the 3-D printing problem. The large number of decision variables, i.e., droplet volumes at each grid point, in high resolution inkjet 3-D printing makes centralized methods

Creating controllers for quadrupedal robot locomotion on platforms that exhibit dynamic behaviors, which are herein termed as dynamic platforms, poses a challenging problem because of the complexity of the associated hybrid, time-varying robot dynamics. Towards tackling this challenge, this article focuses on controller design for quadrupedal robot locomotion on dynamic rigid platforms, which are floating-base

Soft robotics has recently become a popular topic owing to its advantages over conventional rigid robotics. In this article, we introduce a soft robot that can grow with its own structure; its main components include an inflatable tube for its body and a tip with an expansion mechanism. The tube is made of conventional laminated film. It leads the robot to improved applicability. The robot can grow

As the primary effector of human, hand is dexterous, important, and biomechanically complex. How to control the robotic hand as human intends in the human-centered robotic systems is a hot topic to guarantee natural interaction between users and robots. In this article, we investigate the simultaneous and proportional estimation of human's movement intent from surface electromyography (EMG) signals

The performance achieved with traditional model-based control system design approaches typically relies heavily on accurate modeling of the motion dynamics. However, modeling the true dynamics of present-day increasingly complex systems can be an extremely challenging task; and the usually necessary practical approximations often renders the automation system to operate in a nonoptimal condition. This

This article proposes a method to suppress the torque ripple caused by misalignment of the gearbox. Misalignment is a common fault caused by the manufacturing tolerances, and generates torque ripple. Therefore, even if a constant electromagnetic torque is transmitted from the motor to the gearbox, a large torque ripple may be transmitted to the load because of misalignment. In the proposed method,

This article presents a novel guidance and control design for a parcel tethered to a drone in its delivery mission. The proposed proportional-navigation-based guidance, integrated with custom-built control, enables to achieve autonomous payload landing. The novelty of the proposed method lies in two aspects: 1) the guidance law allows for soft landing and 2) the path-following control ensures the swing-free

One of the main challenges in magnetic resonance imaging (MRI) guided interventions is for an instrument to access and track a respiration-induced moving target inside the patient. In this article, we present a mechatronic system that demonstrates such capability for one-dimensional motion in phantom experiments. Our system consists of real-time sensing by MRI acquisition, detection, and localization

In this article, we propose a compact variable gravity compensation (CVGC) mechanism with a geometrically optimized lever shape. The CVGC mechanism can be used to generate gravity compensation torque by employing a cam and lever mechanism and can also amplify the gravity compensation torque by varying the pivot point of the lever. Among these advantages, we aimed to maximize the variable ratio of torque

Inertial sensing suites now permeate all forms of smart automation, yet a plateau exists in the real-world derivation of global orientation. Magnetic field fluctuations and inefficient sensor fusion still inhibit deployment. In this article, we introduce a new algorithm, an extended complementary filter (ECF), to derive 3-D rigid body orientation from inertial sensing suites addressing these challenges

Although there have been several proposed methods and existing prototypes demonstrating the functionality of aerial–aquatic vehicles, most are fundamentally aerial vehicles with varying degrees of operability when submerged. We aim to improve the balance of aerial–aquatic functionality by proposing a morphable vehicle structure, where the rotors can be tilted to allow thrust vectoring when underwater

This article studies the design, modeling, and implementation challenges of a path-following with obstacle avoidance algorithms as guidance, navigation, and control (GNC) architecture of an unmanned surface vehicle (USV) in harbor conditions. First, an effective mathematical model is developed based on system identification, validating the USV model with field-test data. Then, a guidance system is

In this article, we propose a multi-agent robot control framework for coordinated manipulation of multiple micro-objects with Brownian perturbations. In this control approach, several micro-hands with multiple fingertips are first constructed by coordination of optically trapped particles so as to grasp the target micro-objects. The grasped micro-objects are then cooperatively manipulated through coordinative

This article presents an innovative, motor-driven, three-finger compliant gripper for adaptive grasping of size-varied delicate objects. An optimized compliant finger design is identified numerically through a topology optimization method. A stepper motor is used to actuate three identical compliant fingers, which can operate through elastic bending deformation. Finite-element models are developed

In pneumatic muscle actuators (PMAs)-driven robotic applications, there might exist unpredictable shocks which lead to the sudden change of desired trajectories and large tracking errors. This is dangerous for physical systems. In this article, we propose a novel adaptive proxy-based robust controller (APRC) for PMAs, which is effective in realizing a damped response and regulating the behaviors of

The increasing computing and sensing capabilities of modern mobile phones have spurred research interests in developing new visual–inertial odometry (VIO) techniques to turn a smartphone into a self-contained vision-aided inertial navigation system for various applications. Smartphones nowadays use cameras with optical image stabilization (OIS) technology to reduce image blurs. However, the mechanism

This article designs and tests a dominant region based strategy for a group of defenders to intercept an intruder before it enters a target area. The intruder is intelligent in the sense that it makes decisions based on the defenders’ strategies instead of following a predefined path, making the problem a differential game. When the intruder moves slower than the defenders, the optimal strategies are

Parallel mechanisms have been employed as architectures of high-precision vibration isolation systems. However, their performances in all degrees of freedom (DOFs) are nonidentical. The conventional solution to this problem is isotropic mechanism design, which is laborious and can hardly be achieved. This article proposes a novel concept; namely, isotropic control, to solve this problem. Dynamic equations

High-performance actuators are crucial to enable mechanical versatility of wearable robots, which are required to be lightweight, highly backdrivable, and with high bandwidth. State-of-the-art actuators, e.g., series elastic actuators, have to compromise bandwidth to improve compliance (i.e., backdrivability). In this article, we describe the design and human–robot interaction modeling of a portable

Compliant joints can provide safer physical human–robot interaction. To effectively balance the response bandwidth and output impedance, variable stiffness joints have been studied by many researchers. Leaf spring-based variable stiffness joint (LSVSJ) has the advantages of easy construction and large stiffness range. This article presents the design and validation of a novel LSVSJ with reconfigurability

In this article, a new control scheme is proposed to enable multiple quad-copters to cooperatively carry a cable-suspended payload. This cascaded controller takes into account the quad-copters underactuation and exploits the energetic passivity of the payload-cables-drones multibody system to achieve stable control. The controller is simple and requires no information about the cables tensions. A storage

Along with the traditional motion control demands, human–machine collaboration properties are becoming increasingly important in modern robotic control system. The collaboration requires both robot's dynamics and payload dynamics, in which the former can be identified offline, whereas the latter has to be estimated online. However, the accurate payload estimation cannot be guaranteed by the traditional

Multiextended target tracking (METT) has important applications in many fields, including autonomous vehicles, traffic flow monitoring, etc. However, as an acknowledged METT algorithm, the labeled multi-Bernoulli (LMB) filter cannot handle the intertarget occlusion problem, which frequently observed among METT, leading to an estimated trajectory break and even target loss. To tackle this problem, this

Inverse reinforcement learning (IRL) is a technique for automatic reward acquisition, however, it is difficult to apply to high-dimensional problems with unknown dynamics. This article proposes an efficient way to solve the IRL problem based on the sparse Gaussian process (GP) prediction with $l_1$ -regularization only using a highly limited number of expert demonstrations. A GP model is proposed to

In this article, a novel real-time time-optimal trajectory planning (TOTP) approach is proposed for rotorcrafts under velocity constraints and complex nonconvex thrust, attitude input constraints. Different from existing works, the proposed method is the first real-time TOTP solution for rotorcrafts subject to velocity constraints and these nonconvex input constraints. The key insight is to transform

In this article, we develop two end-effectors for robot-assisted microsurgery with the aim of implementing compact and lightweight devices that can drive hand-operated commercial surgical instruments, such as forceps and scissors. To achieve this objective, we mainly consider the type of actuator and the driving mechanism that influence not only the working performance but also the structural features

Power management is a vital technology to increase the economy of fuel cell hybrid vehicles. To overcome the deficiency of most existing optimization approaches, in this article, a modified model predictive control-based optimal strategy of power management is proposed for fuel cell hybrid vehicles. Besides, a partial least squares-based load estimation method is utilized to avoid the assumption of

Soft robotics has attracted growing attention due to its compliant structure, safe operation, and promising applications in constrained and unstructured environments. Octopus can employ its arm and suckers to catch prey in complex environments. Intrigued by these capabilities, we explored a new approach in sensing, modeling, and control of a bioinspired soft robot that enables both bending and suction

Several works have addressed the issue of fault tolerance in multirotors in case of a rotor total failure, particularly their ability to keep full independent control of attitude and altitude. It has been proven that to achieve this, a minimum of six rotors is needed. In this article, the performance of several standard and nonstandard hexarotor structures is analyzed, both for a nominal case (without

The clutch touchpoint of an automotive transfer case is a key parameter for accurate clutch torque control, which varies over time due to clutch wear, clutch plate temperature change, and clutch actuation system part-to-part variation. Typically, the touchpoint displacement is unknown and needs to be estimated online. This article, based on the clutch actuation system model, proposes an adaptive scheme

Motivated by the need to develop safe exoskeletons for collocated joint rehabilitation during the early stage of stroke recovery, this article presents a pantographic exoskeleton (PGE) capable of multi-degree-of-freedom motions in a single-joint collocated with the impaired joint. With minimum internal joint reactions in the presence of misalignment, the PGE “traces” the natural joint motion “like

Soft continuum manipulators based on pneumatic artificial muscles offer the advantages of high compliance, complex environmental adaptability, and safe interaction with humans and work environments. However, most of them cannot continuously change their stiffness under a fixed end position due to the strong coupling of position and stiffness. To overcome this problem, this article develops a light

A mechanism to derive nonrepetitive coverage path solutions with a proven minimal number of discontinuities is proposed in this work, with the aim to avoid unnecessary, costly end-effector lift-offs for manipulators. The problem is motivated by the automatic polishing of an object. Due to the nonbijective mapping between the workspace and the joint-space, a continuous coverage path in the workspace

This article proposes a novel efficient sampling strategy to rapidly estimate the distribution of stiffness over an inhomogeneous object with a highly limited number of sample points taken from the object surface. The stiffness on the object surface is modeled as a mass–spring system, and its distribution is estimated via tactile exploration using Gaussian process regression. The main objective of

A novel control scheme utilizing fractional-order terminal sliding mode control with sliding perturbation observer (FOTSMCSPO) is proposed herein. It was used to solve the trajectory tracking problem on a seven-degree-of-freedom robot manipulator. The fractional-order terminal sliding mode in FOTSMCSPO provides a finite convergence time for reaching the sliding surface. In this article, a sliding perturbation

This article proposes an adaptive implicit inverse control scheme for a class of discrete-time hysteretic nonlinear systems. The Prandtl–Ishlinskii model is employed to characterize the hysteresis loop in piezoelectric actuator. The main contributions are as follows: 1) by using the dynamic surface control technique, which introduces the digital first-order low-pass filter, the original control system

To enhance the precision manufacturing of microstructures, a 3-D isotropic microprobe based on three-flexible-hinge suspension and orthogonal microball collimation was developed. First, the sensing principle of the microprobe was investigated by analyzing its displacement transfer principle and the displacement measurement principle of the orthogonal microball collimation optical paths. Second, the

This article presents a new mobile platform with two-degree-of-freedom (2-DOF) transformable wheels for service robots, which can overcome steps and stairs of various sizes encountered in indoor environments. The concept of the 2-DOF transformable wheel is introduced and the required transformation ranges are examined. In this article, a five-bar PRRRP mechanism is adopted as the base mechanism for

The number of high-rise buildings is increasing worldwide, and the demand for window maintenance and cleaning has increased accordingly. However, there is an increased desire to substitute robots with human workers because of the occurrence of many accidents. Although many window-cleaning robots have been developed, almost all the robots cannot passively pass obstacles on the outer walls of buildings

The intrinsically reciprocating motion in fishlike propulsion causes severe attitude instability of a robotic fish, which poses enormous challenges for environmental perception and autonomous operation. To address this issue, in this article, we propose a reaction-wheel-based control framework for guaranteeing the roll stability of the robotic fish. The mechatronic design and dynamic model of the designed

This article introduces a new mobile robot with angled spoke-based wheels (ASWs). An ASW is designed by analyzing the combination of the assembling angle with the spokes and the assembling angle with the wheel shaft. It has a specific trajectory in which the spokes are perpendicular to and parallel to the ground simultaneously. Therefore, this wheel is in contact with the ground similar to a conventional

This article presents assistive control sche-mes for rehabilitation robots. The objective was to develop control strategies to follow a predefined path by maximizing the active participation of impaired subjects during training sessions. For this purpose, the path following task was defined in the velocity domain by constructing a desired velocity field around the path, and two different controllers

In metal cutting, a good understanding of both the elastic-plastic deformation and the mechanical behavior of the workpiece material in the primary shear band (PSB) is essential to optimize machining process and ensure product quality, particularly when machining hard-to-cut materials (such as Titanium alloys) with a low thermal conductivity that gives rise to thermal stress localization near the tool-chip

In many existing formation control approaches for nonholonomic mobile robots, the leader velocity is required to be measured and transmitted to the follower for controller design. Though some existing approaches can remove such a requirement, they have their respective shortcomings. For example, some are discontinuous, while others only ensure local closed-loop stability. In this article, we develop

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 ±300 N in the vertical GRF (vGRF) direction and the anterior-posterior GRF (apGRF) direction, respectively, with accuracies of 2.81 ± 0.29% and 1.67 ± 0.15%, respectively

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