Abstract This paper addresses the trajectory tracking problem of robotic manipulators subject to disturbances, model uncertainties, and input/state constraints by proposing a higher-order-observer-enhanced time-delay incremental model predictive control strategy, termed HOB-TIMPC. Time-delay estimation (TDE) is used to approximate the lumped nonlinear dynamics and reduce dependence on an accurate nominal model. To mitigate the residual estimation error caused by time-varying disturbances and unmodelled dynamics, a higher-order observer (HOB) is introduced to compensate the TDE error before constructing the incremental prediction model. The compensated model is then embedded into an IMPC framework with explicit input and state constraints. Unlike conventional TIMPC schemes that directly build the prediction model from TDE-estimated dynamics, the proposed method constructs the prediction model using HOB-compensated TDE dynamics. Thus, the main contribution lies in the structured integration of HOB-based TDE-error compensation into a TDE-based IMPC formulation, rather than in establishing a fundamentally new control theory. Stability is analyzed for the fixed-horizon compensated IMPC formulation, while the variable prediction horizon is treated as a bounded practical scheduling strategy. Lyapunov analysis shows the boundedness of the HOB estimation error and the input-to-state stability of the closed-loop system within a local region of the reachable reference trajectory. Simulations and experiments on a self-built 2-DOF robotic manipulator demonstrate that, under the tested payload and trajectory conditions, HOB-TIMPC improves tracking accuracy and disturbance rejection compared with the tested baseline methods.

Hydrogel magnetic microrobots are promising for targeted drug delivery, but large drug-loaded microrobots are difficult to manipulate as stable swarms under conventional rotating magnetic fields. Here, shell-core magnetic capsule hydrogel microrobots (CHMs) were fabricated by coaxial microfluidics and actuated using a composite magnetic field system. The CHMs exhibited tunable diameters of 100-600 μm and a saturation magnetization of 5.4 emu g⁻1. Under rotating magnetic fields, individual CHMs achieved torque-driven rolling with a maximum velocity of 0.76 mm s⁻1. Under programmable rotating gradient magnetic fields, CHM swarms reached a maximum collective velocity of 0.72 mm s⁻1 and reversibly transformed among clustered, elongated, chain-like, and dispersed morphologies. Aggregation and dispersion efficiencies reached 94% and 90%, respectively, within 1-8 Hz. The CHM swarm navigated confined channels, crossed obstacles, and achieved targeted locomotion in a simulated gastrointestinal environment. CHMs also exhibited pH-responsive drug release, with cumulative release of 4% at pH 1.2 and 23% at pH 7.6 within 10 h. Unlike conventional magnetic swarms relying on dipole-induced self-assembly, this strategy uses a movable magnetic gradient point to collectively confine and transport CHMs, providing a high-integrity non-assembly swarm control approach for targeted drug delivery.

To address the issues of complex fabrication processes and the limited large-area field emission performance of conventional carbon nanotube (CNT) cold cathodes, a multilayer CNT cold cathode structure with dual-layer synergistic electron emission characteristics was fabricated based on screen-printing technology. The influence of the geometric emission region ratio (eta) on the field emission performance was systematically investigated, and field emission experiments were conducted to verify the enhancement effect of structural optimization on electron emission performance. The results demonstrate that the screen-printed CNT cathode exhibits a turn-on field of 1.01 V/mu m, a high field enhancement factor of 9244, and a current density of 1.325 mA/cm2. When the geometric emission region ratio (eta) ranges from 6 to 11, the structure achieves a peak current gain exceeding 90%, with a maximum current density of 2.048 mA/cm2. During the 2 h continuous emission test, the current fluctuation remained below 3%, demonstrating good emission stability. While maintaining good process manufacturability, the proposed structure achieved an effective enhancement in field emission performance, providing a new research approach for the design of large-area, high-performance CNT cold cathode electron sources.

During traditional open surgery for liver tumor resection, surgical failures often occur because surgical tools touch the tumor or deviate from the surgical path. To solve these problems, this paper proposes an intelligent early warning system for tumor resection based on surgical navigation. Firstly, to address the issue of collisions between surgical tools and tumors, a safe area for surgical tools to cut tumors is established. A mechanism for early warning of collisions between surgical tools and tumors has been constructed. Secondly, the characteristics of surgical paths of different shapes are analyzed. A mathematical calculation model for the distance of surgical tools deviating from surgical paths of different shapes during tumor resection is proposed. Then, a warning model for the deviation of surgical tools from the surgical path is constructed. Finally, experiments are designed to verify the relevant performance of the early warning system proposed in this paper. The experimental results show that the accuracy of the early warning system proposed in this paper is about 95%, and the scope of tumor resection is controlled within 4 mm. Note to Practitioners-At present, for open liver tumor resection surgeries, surgeons mostly rely on experience to determine the positional relationship between surgical tools and the tumor. Surgeons also rely on intuition to determine whether there is a deviation between the surgical tools and the planned surgical path. This leads to the fact that during the operation, surgical tools are prone to touching the tumor or deviating the surgical path, resulting in the failure of the operation. This paper proposes an intelligent and automated surgical early warning system. A mechanism for early warning of collisions between surgical tools and tumors has been developed, which can alert surgeons in real time whether surgical tools are in a safe area. Meanwhile, a model for early warning of the surgical tool deviation from the surgical path is proposed to minimize the error in tumor resection and improve the success rate of the surgery as much as possible.

Adhesive hydrogels are widely used for wearable sensors, but their swelling feature can affect adhesion and sensing ability in aqueous environments. To address this limitation, a conductive poly(acrylic acid)-poly(butylacrylate)-Cu2+ (PAA-PBA-Cu2+) hydrogel was constructed using a solution displacement method, resulting in abundant interactions within the hydrogel matrix. Due to these interactions, the hydrogel exhibited good mechanical strength (293% tensile strain and 103 kPa elastic modulus), anti-swelling property, and adhesion strength (37.6 kPa on Cu-based substrate). The PAA-PBA-0.1 M-based sensor can present well sensing ability in both air and underwater environment, which can sensitively distinguish the different body actions. The anti-swelling performance and adhesion have endowed the sensor with stable and accurate signal output in underwater environment, respectively. Additionally, the sensor can also be used for underwater communication, which can guarantee human safety in underwater operations. In addition, based on the fine photothermal conversion ability of Cu2+, the hydrogel can offer temperature compensation potential, thereby ensuring the stability and sensitivity of the signal outputs in various underwater environments.

This study investigates the electrical property modulation of single-walled carbon nanotubes through the engineering of necking topological defects induced by plastic deformation. Combining molecular dynamics simulations and first-principles calculations (density functional tight-binding coupled with nonequilibrium Green's function formalism), we demonstrate that controlled tensile loading at 3500 K generates stable necking configurations with Stone-Wales-like defects and 5-8-5 vacancy defects when strain rates are maintained within 8-11%. System analysis reveals that the 5-8-5 defect primarily suppresses electron transport through two mechanisms: creating a transmission trough near 0.14 eV and introducing multiple low-transmission troughs within the bias voltage window. These effects induce nonlinear current-voltage characteristics with conductance plateaus in the +/- 1.2 V range, mimicking the behavior of semiconductor heterojunction rectification. In contrast, SW-like defects cause partial attenuation of the transmission coefficient without forming a significant bandgap. Necking diameter reduction exhibits a strong positive correlation with conductivity degradation, while axial necking length (4-12-unit cells) shows a negligible impact. The 5-8-5 defect-mediated structures demonstrate superior potential for creating functional molecular junctions compared to SW-like configurations. By establishing the correlation between plastic deformation parameters (temperature, strain rate), necking geometry (diameter, defect type), and electron transport characteristics of carbon nanotubes, this paper provides an approach for designing carbon-based nanodevices based on mechanical strain regulation. It opens an avenue for researching carbon-based nonlinear nanoelectronic devices.

The traditional optical tracking system is easily affected by occlusion and a narrow field of vision, which leads to the failure of surgical instrument tracking. To solve this problem, a multi-target tracking method based on multicamera module information fusion is proposed. Firstly, a multi-target tracking block is installed at the end of the surgical instrument. A method of solving the end position of surgical instruments based on multi-object tracking is proposed to improve the success rate of surgical instrument tracking. Secondly, motion blur is easy to occur in surgical instrument tracking. A method to reduce the tracking failure caused by motion blur is proposed to improve the sharp edge of the image. Then, a method of information fusion of multi-camera module is proposed to track surgical instruments. Finally, experiments are designed to verify the stability and accuracy of the proposed method. The tracking accuracy is 1.89 +/- 0.24 mm.

The classic model-free controller, the time delay controller (TDC), operates under complex conditions with large external disturbance changes and suffers from time delay estimation (TDE) errors, which can lead to reduced controller performance. To compensate for the TDE error, a novel compensator is proposed in the TDC framework by considering the TDE error as a separate disturbance term. This compensator innovatively combines a gradient error compensator and a disturbance observer to correct fast-time-varying TDE errors using the gradient error compensator and slow-time-varying TDE errors using the disturbance observer. Furthermore, a high-order time delay observer (HOTDEO) is designed based on the first-order disturbance observer. Compared to the first-order and second-order observers, the HOTDEO has a lower steady-state error. The designed high-order time delay compensator is used as a supplementary term for traditional TDC and applies to various TDC frameworks. Additionally, the stability theory for both the observer and controller is analyzed in detail, and their convergence conditions are verified. Finally, simulation and experimental results demonstrate that the proposed high-order time delay compensator significantly improves the tracking accuracy and robustness of the control algorithm, particularly in terms of TDE error compensation. This research provides valuable contributions to the further development of TDC in the field.

In cancer combination therapy, micro-robot systems that integrate multiple therapeutic functions have emerged as a key direction for overcoming the limitations of traditional treatments. This study proposes a magnetic thermosensitive hydrogel capsule micro-robot that combines both drug-targeted delivery within blood vessels and local magnetic hyperthermia therapy. By introducing acrylamide and sodium alginate to modify the poly(N-isopropyl acrylamide) hydrogel system, the thermal response characteristics and drug-loading capacity of the micro-robot carrier are optimized. A multi-coaxial co-flow microfluidic chip is employed to achieve the directed encapsulation of Fe3O4 nanoparticles and the rapid, controlled preparation of single-core and core-shell structured spherical micro-robots. The core-shell structure enables the simultaneous loading of hydrophilic and hydrophobic drugs. Under the influence of a high-frequency alternating magnetic field, the local temperature around the micro-robot increased from 21 °C to 42 °C within 4 minutes, successfully triggering the phase transition contraction of the hydrogel and releasing the drug while also reaching the temperature threshold for thermal therapy. Additionally, this study established a visual feedback, magnetically driven system, with the micro-robot achieving a maximum movement speed of 3.47 mm s-1 under a magnetic field strength of 7.4 mT, thereby realizing millimeter-level positioning accuracy and complex curve trajectory tracking in vascular microchannels that simulate a blood environment. Experimental results indicate that the prepared multimodal hydrogel capsule microrobots possess excellent targeted movement capabilities, meeting the functional requirements for a synergistic "thermotherapy-chemotherapy" treatment, and demonstrate potential application in the development of low-toxicity, high-efficiency tumor combination therapy.

Carbon nanotubes (CNTs) are recognized as excellent field-emitting materials due to their superior electrical properties, which have significant advantages in advanced vacuum electronics. This study explores the field emission characteristics in CNTs enhanced by thermomechanical tensile processes. In this study, molecular simulations were performed using LAMMPS software to observe the structural changes of various carbon nanotubes during thermomechanical processing. In addition, COMSOL Multiphysics was used to analyze the field emission performance of the CNT after fracture. The results show that the thermomechanical stretching process contributes to the formation of sharp fractured surfaces during the fracture of single-walled carbon nanotubes (SWCNTs), thereby significantly improving the field emission performance with a maximum surface electric field increase of up to 3.58-fold. Since the long-arm tip of the CNT array is pulled out, its field emission performance is also significantly enhanced, with a maximum increase of 4.21-fold. However, this enhancement tends to decrease as the diameter of the carbon nanotubes or the size of the array increases. The study concludes that thermomechanical stretching can effectively improve the field emission performance of small-diameter carbon nanotubes and arrays, providing a theoretical basis for designing carbon-based nanoelectron emission devices.

In this paper, a new localization method of liver tumors based on structured light is proposed to achieve the accurate resection of liver tumors. Firstly, the preoperative liver model and intraoperative liver surface are completed respectively based on CT sections and structured light. Secondly, the 3D reconstruction of liver surface based on structured light is used as the reference surface for registration. A common ICP algorithm and an improved ICP algorithm based on statistics are proposed to complete the rough and fine registration of liver surface. In this paper, the theory of PBD is introduced, and the registration results are used to guide the preoperative deformation of the liver model. Finally, the method of 3D non-rigid localization of liver tumors proposed in this paper is verified by experiments. In addition, the effectiveness of the proposed method is compared with that of the tumor localization obtained by the finite element analysis and Coherent point drift methods. The experimental results show that the average localization error of liver tumor is 1.24 mm. The time spent during the entire process of tumor localization is kept under fifteen seconds. The method presented in this paper meets the needs of surgeons in the intraoperative process.

Establishing low-resistance ohmic contact is critical for developing electronic devices based on traditional silicon and new low-dimensional materials. Due to unprecedented electronic and mechanical properties, the one-dimensional carbon nanotubes (CNTs) have been used as source/drain, gate, or tunnel to fabricate transistors. However, the mechanism causing low-resistance ohmic contact is not clear yet. Here, the hybrid atomic force microscopy-scanning electron microscopy (AFM-SEM) instrument was developed to establish lower-resistance ohmic contact between a radial compressed deformed multiwalled CNT bundle and high work function metal (platinum and gold). The radial compression structure under strong van der Waals attraction was in situ characterized through the SEM image to obtain the diameter and width and through AFM to get height and to perform nanoindentation, indicating that Pt has the smaller radial compression deformation. Molecular dynamics simulations exhibit that compared to Pt, a wider ribbon-like graphene layer formed when the radial compressed CNTs contacted with Au. The bond forming and electron orbital overlapping between C atoms of deformed CNTs and the high work function metal atom is beneficial for good electrical contact.

Single-wall carbon nanotubes (SWCNTs) have unique electrical properties, making them potential silicon and copper replacements in semiconductors and nanointerconnects. Current research focuses on single vacancy defects, needing expansion to other topological defects. In this study, we account for the presence of topological defects and develop a model that demonstrates their impact on the electrical properties of carbon nanotubes (CNTs) by using a degradation coefficient for the conductivity. This study employs density functional theory combined with the nonequilibrium Green's function method to systematically analyze the influence of various topological defects on the electronic structure and transport characteristics of SWCNTs, using I-V curves, transmission spectra, and 3D transmission spectra. The results indicate that defects of the same type substantially degrade the electronic transport properties of CNTs, with the degree of degradation varying based on the defects' positions and quantities. This degradation can result in a reduction of over 20% in the electronic transport capacity compared with ideal CNTs. A linear positive correlation exists between the extent of degradation and the magnitude of the defects. Furthermore, the presence of a small number of 5-8-5 defects and Stone-Wales defects can induce bandgap opening from 0.109 to 0.549 eV for the bandgap of (6,6) CNTs. However, a high defect concentration reduces the bandgap, potentially to zero. Notably, regardless of whether the bandgap increases or decreases, the bandgap of (6,6) CNTs remains smaller than the bandgap of (11,0) semiconductor CNTs, leading to the transition of SWCNTs to metallic conductors. Finally, the differential conductivity diagram of CNTs with topological defects was analyzed, demonstrating that introducing specific 5-8-5 defects can effectively regulate the electrical properties of the CNTs. This paper analyzes the effects of defects on the CNTs electrical properties and finds a regulatory effect, providing a reference for carbon-based transistor manufacturing.

Hydrogel microspheres stand out in drug delivery due to their small particle size, biocompatibility and good internal stability. In this paper, pH-sensitive hydrogels are prepared by microfluidic technology for targeted drug delivery in the small intestine. A coaxial dual-channel microfluidic chip is constructed. By analyzing the effects of flow rates and three fracture stages (Rayleigh-Plateau instability crushing stage, pressure difference crushing stage and shear force crushing stage) on the size of hydrogel microspheres, the optimal control stage of the microsphere size is determined (shear force crushing stage). Based on this, the accurate control model of the hydrogel microsphere size is proposed. In addition, based on the coaxial dual channel microfluidic chip, a monolayer hydrogel microcapsule loaded with Indometacin is prepared. The core-shell hydrogel microcapsules loaded with Indometacin are prepared by an improved coaxial three channel microfluidic chip. The swelling rates of both microcapsules in simulated intestinal fluid are significantly higher than those in simulated gastric fluid. The results of in vitro simulated release experiments show that the two hydrogel microcapsules basically do not release in simulated gastric juice. In simulated intestinal fluid, single-layer hydrogel microcapsules show rapid release, while core-shell hydrogel microcapsules showed slow release. In conclusion, the alginate-based hydrogel microcapsules have good stability and pH sensitivity, and are suitable for targeted drug delivery in the small intestine.

Vibration is an essential indicator that reflects the robust status of industrial robots. To improve the detection effect and resilience for articulated industrial robot in-situ, a novel non-invasive self-diagnostic method is proposed. Feasible embedded motor current is used to calculate the extended Teager indicator at a low sampling rate. Compared with common Teager and other indicators, both theoretical analysis and experimental data indicate the effectiveness and robustness of the proposed method.

The traditional surgical navigation system for open liver tumor resection has some problems, such as low tumor localization accuracy, high complexity of system operation, and heavy surgical burden on surgeons. To solve these problems, this paper proposes an augmented reality surgical navigation system based on coaxial projection of surgical paths. Firstly, the intraoperative tumor localization module is used to locate the tumor. An augmented reality coaxial projection module for surgical path projection has been developed. In addition, a unified view of the camera and projector in the module is designed. Secondly, we propose an algorithm for image registration and fusion. The actual scene image of the liver captured by the augmented reality coaxial projection module is registered and fused with the model image to determine the tumor ' s location in the surgical image. Then, surgical path planning is carried out for the tumors in the surgical images. An augmented reality coaxial projection module projects the surgical path onto the surface of the liver to assist surgeons in tumor resection. Finally, we validate the performance of our proposed surgical navigation system through multiple sets of experiments on tumor resection. The experimental results show that the average error and time of tumor resection based on this system are 2.95 mm and 59 s, respectively. It can be seen that the system proposed in this study achieved better results under laboratory conditions. The development of this system lays the foundation for our future research in clinical surgical navigation systems.

区别于传统作业车间调度问题,研究一种工件之间具有优先约束的柔性作业车间问题.首先建立多目标静态调度模型,利用JAYA方法进行求解,通过实验得到变异因子的最佳值.其次,提出一种新的两阶段的动态调度策略,在静态调度结果上进行调整,同时对短期和长期恢复的扰动问题重调度.实验证明,提出的动态调度方法能同时有效减少完工时间和机器偏移情况.

Carbonnanotubes (CNTs) have excellent electrical properties. However,it is challenging to demonstrate these properties in actual electrochemicalmeasurements fully. Previous research has improved the electricalproperties of CNTs through welding experiments. But the mechanismof the conductivity enhancement is still unclear. The welding processlacks adequate mechanistic studies and theoretical models. This articlepresents a theoretical model of a CNT circuit with staggered electrodes,which considers the effect of twist angle on a CNT bundle. A weldingmodel of the CNT bundle circuit is also developed based on the structuralchanges of CNTs after welding and characterized by the resistanceratio of the CNT circuit pre- and post-welding. The welding modelis analyzed to explore how the quantity, diameter, and length of CNTsin the bundle affect the welding effect. An electrical measurementsystem for CNTs was established to validate the welding model usinga nanomanipulation system compatible with a scanning electron microscope.Then, a constant voltage and long-duration electric welding experimentwas performed, which showed that the conductivity was enhanced about1.5-4 times after welding. The results also demonstrated thatlonger and fewer CNTs in the bundle could improve the electrical conductivityby the welding process more significantly. These findings were consistentwith the trend of the welding model. This article establishes a weldingtheoretical model of the CNT bundle with staggered electrodes, whicheffectively accounts for the electrical conductivity enhancement duringCNT welding and will help more fully express excellent performancein carbon-based nanoelectronic devices, nanoelectromechanical systems,and electrocatalysts in its manufacturing stage.

Microrobots for targeted drug delivery in blood vessels have attracted increasing interest from researchers. In this work, hydrogel-based capsule microrobots are used to wrap drugs and deliver drugs in blood vessels. In order to prepare capsule microrobots of different sizes, a triaxial microfluidic chip is designed and built, and the formation mechanism of three flow phases including the plug flow phase, bullet flow phase and droplet phase during the preparation of capsule microrobots is studied. The analysis and simulation results show that the size of the capsule microrobots can be controlled by the flow rate ratio of two phases in the microfluidic chip, and when the flow rate of the outer phase is 20 times that of the inner phase in the microfluidic chip, irregular multicore capsule microrobots can be prepared. On this basis, a three degree of freedom magnetic drive system is developed to drive the capsule microrobots to reach the destination along the predetermined trajectory in the low Reynolds number environment, and the magnetic field performance of the magnetic drive system is simulated and analyzed. Finally, in order to verify the feasibility of targeted drug delivery of the capsule microrobots in the blood vessel, the motion process of the capsule microrobots in the vascular microchannel is simulated, and the relationship between the motion performance of the capsule microrobots and the magnetic field is studied. The experimental results show that the capsule microrobots can reach a speed of 800 μm s-1 at a low frequency of 0.4 Hz. At the same time, the capsule microrobots can reach a peak speed of 3077 μm s-1 and can continuously climb over a 1000 μm high obstacle under a rotating magnetic field of 2.4 Hz and 14.4 mT. Experiments show that the capsule microrobots have excellent drug delivery potential in similar vascular curved channels driven by this system.

Based on the tight binding density functional theory and non-equilibrium Green's function, the electronic transport properties between the branches of Y-type branched carbon nanotubes are studied. Characterize the electron transport properties using a current voltage curve, and study the regulatory effect of current flowing through the other two branches by changing the voltage of the third branch. AFM-CNT nanoknife were prepared through experiments using AFM probes and carbon nanotube. Y-type branched carbon nanotube was cut and picked up through a synergistic operation strategy of AFM-CNT nanoknife and tungsten needles, and electrical performance experiments were conducted on Y-type branched carbon nanotube.