Multimodal Control Research Articles

Learning-Based Multimodal Control for a Supernumerary Robotic System in Human-Robot Collaborative Sorting

Learning-Based Multimodal Control for a Supernumerary Robotic System in Human-Robot Collaborative Sorting

MotionGPT: Finetuned LLMs Are General-Purpose Motion Generators

Generating realistic human motion from given action descriptions has experienced significant advancements because of the emerging requirement of digital humans. While recent works have achieved impressive results in generating motion directly from textual action descriptions, they often support only a single modality of the control signal, which limits their application in the real digital human industry. This paper presents a Motion General-Purpose generaTor (MotionGPT) that can use multimodal control signals, e.g., text and single-frame poses, for generating consecutive human motions by treating multimodal signals as special input tokens in large language models (LLMs). Specifically, we first quantize multimodal control signals into discrete codes and then formulate them in a unified prompt instruction to ask the LLMs to generate the motion answer. Our MotionGPT demonstrates a unified human motion generation model with multimodal control signals by tuning a mere 0.4% of LLM parameters. To the best of our knowledge, MotionGPT is the first method to generate human motion by multimodal control signals, which we hope can shed light on this new direction. Visit our webpage at https://qiqiapink.github.io/MotionGPT/.

Compliant liquid dampers-inerter for mitigating wind-, wave-, and earthquake-induced vibrations of monopile offshore wind turbines

This work explores the possibility of installing compliant liquid dampers-inerter (CLDI) on monopile offshore wind turbines (OWTs) for controlling combined vibrations from wind, wave, and earthquakes. For numerical demonstration, the 5-MW NREL monopile OWT is taken up. Seven different wind speeds and a set of 20 earthquakes are considered. Hence, the means of structural response quantities are chosen. The peak and root mean square (RMS) values of displacement and acceleration responses of tower-top are monitored. A genetic algorithm-based multi-objective optimization is performed, and the optimum CLDI parameters are estimated for different ranges of inertance ratio and inerter topology. The optimization comprises four cases: firstly, minimizing the mean of peak responses and second, minimizing the mean of RMS responses in fore-aft (FA) as well as in side-side (SS) directions. Hence, each case has four objective functions, covering two loading scenarios, wind & wave, and earthquake. With the obtained optimum parameters, considering all these cases, the control effectiveness of CLDI is further investigated in time and frequency domains. The time domain results reveal that the CLDI controls the SS vibrations effectively, whereas, in FA direction, the efficiency is marginally less. Additionally, the frequency domain plots indicate the multi-mode control capability of CLDI.

Fluoroscopic Guided Lumbar Erector Spinae (ESP) Field Blocks: A New Technique and Radiographic Analysis

IntroductionLumbar Erector Spinae (ESP) field blocks have become a common postoperative treatment for surgical pain. The use of long-acting medications like liposomal bupivacaine (Exparel) has become a major component of multi-modal postsurgical pain control. Traditionally ESP injections have been performed using ultrasound (U/S) guidance by an anesthesiologist. Spine surgeons have begun to utilize these liposomal injections in their procedures for post-operative pain management. Our study describes a fluoroscopic guided ESP field block technique which provides reproducible muscular coverage and pain control for spine surgery. Material and MethodsSixty patients undergoing single level lumbar fusion were treated preoperatively with bilateral fluoroscopically guided lumbar erector spinae ESP field blocks with liposomal bupivacaine. We looked at two different injection locations involving the ESP or multifidus muscle fascial planes. The injections contained Iohexal, which was used to evaluate the coverage area of the injection. The levels of coverage were recorded, and post-operative pain control was measured immediately, postoperatively, and at 24 hours. ResultsFluoroscopic field blocks at the L3-4 level were found to provide at least four levels of vertebral coverage rostral-caudally in both ESP and MF fascial planes. Pain was well controlled in both injection sites. ConclusionSurgeon-administered fluoroscopic guided ESP field blocks provided a reliable and consistent pattern of coverage with good postoperative pain control. This technique can be easily adopted by spine surgeons.

Predicting consequences of COVID-19 control measure de-escalation on nosocomial transmission and mortality: a modelling study in a French rehabilitation hospital

Infection control measures are effective for nosocomial COVID-19 prevention but bear substantial health-economic costs, motivating their "de-escalation" in settings at low risk of SARS-CoV-2 transmission. Yet consequences of de-escalation are difficult to predict, particularly in light of novel variants and heterogeneous population immunity. To estimate how infection control measure de-escalation influences nosocomial COVID-19 risk. An individual-based transmission model was used to simulate SARS-CoV-2 outbreaks and control measure de-escalation in a French long-term care hospital with multi-modal control measures in place (testing and isolation, universal masking, single-occupant rooms). Estimates of COVID-19 case fatality rates (CFRs) from reported outbreaks were used to quantify excess COVID-19 mortality due to de-escalation. In a population fully susceptible to infection, de-escalating both universal masking and single rooms resulted in hospital-wide outbreaks of 114 (95% CI: 103-125) excess infections, compared with five (three to seven) excess infections when de-escalating only universal masking or 15 (11-18) when de-escalating only single rooms. When de-escalating both measures and applying CFRs from the first wave of COVID-19, excess patient mortality ranged from 1.57 (1.41-1.71) to 9.66 (8.73-10.57) excess deaths/1000 patient-days. By contrast, when applying CFRs from subsequent pandemic waves and assuming susceptibility to infection among 40-60% of individuals, excess mortality ranged from 0 (0-0) to 0.92 (0.77-1.07) excess deaths/1000 patient-days. The de-escalation of bundled COVID-19 control measures may facilitate widespread nosocomial SARS-CoV-2 transmission. However, excess mortality is probably limited in populations at least moderately immune to infection and given CFRs resembling those estimated during the 'post-vaccine' era.

Optimization Method of Multi-Mode Model Predictive Control for Wind Farm Reactive Power

This paper presents a novel approach for optimizing wind farm control through the utilization of a combined model predictive control method. In contrast to conventional methods of controlling active and reactive power in wind farms, the suggested approach integrates a wind power prediction model driven by a neural network and a state-space model for wind turbines. This combination facilitates a more precise forecast of active power, thereby enabling the dynamic prediction of the range of reactive power output from the wind turbines. When combined with the equation of state in wind farm space, it is possible to accurately optimize the reactive power of a wind farm. Furthermore, the impact of active power on voltage fluctuations in the wind farm collector system was examined. The utilization of model predictive control enhances voltage regulation, optimizes system redundancy, and increases the reactive capacity. Sensitivity coefficients were calculated using analytical methods to enhance computational efficiency and to resolve issues related to convergence. In order to validate the proposed methodology and control scheme, a wind farm simulation model comprising 20 turbines was developed to assess the feasibility of the scheme.

Multimodal sensory control of motor performance by glycinergic interneurons of the mouse spinal cord deep dorsal horn

Sensory feedback is integral for contextually appropriate motor output, yet the neural circuits responsible remain elusive. Here, we pinpoint the medial deep dorsal horn of the mouse spinal cord as a convergence point for proprioceptive and cutaneous input. Within this region, we identify a population of tonically active glycinergic inhibitory neurons expressing parvalbumin. Using anatomy and electrophysiology, we demonstrate that deep dorsal horn parvalbumin-expressing interneuron (dPV) activity is shaped by convergent proprioceptive, cutaneous, and descending input. Selectively targeting spinal dPVs, we reveal their widespread ipsilateral inhibition onto pre-motor and motor networks and demonstrate their role in gating sensory-evoked muscle activity using electromyography (EMG) recordings. dPV ablation altered limb kinematics and step-cycle timing during treadmill locomotion and reduced the transitions between sub-movements during spontaneous behavior. These findings reveal a circuit basis by which sensory convergence onto dorsal horn inhibitory neurons modulates motor output to facilitate smooth movement and context-appropriate transitions.

Research on the Multi-Mode Composite Braking Control Strategy of Electric Wheel-Drive Multi-Axle Heavy-Duty Vehicles

Electric wheel-drive multi-axle heavy-duty vehicles have the characteristics of strong maneuverability and good passability, thereby they are widely used in heavy equipment transportation. However, current research on the composite braking of multi-axle heavy-duty vehicles is rare, which is not conducive to improving braking performance and braking energy utilization efficiency. This work proposes a multi-mode composite braking control strategy for the five-axle distributed electric wheel-drive heavy-duty vehicle. Firstly, given the differences in braking dynamics between two-axle vehicles and multi-axle vehicles, the brake dynamics characteristics of multi-axle vehicles are analyzed, and the vehicle dynamics model of multi-axle vehicles is constructed. Next, a multi-mode composite braking control strategy including a fully electric braking state and hybrid electro–hydraulic braking state is proposed in order to improve the braking energy recovery and braking stability. Finally, a hardware-in-the-loop simulation system is established, and the single-braking conditions and China heavy-duty commercial vehicle test cycle-heavy truck (abbreviated as CHTC-HT) are conducted to verify the performance of the braking control strategy. The results indicate that the recaptured braking energy and braking stability are significantly increased by applying the control strategy proposed in this work.

Achromobacter species (sp.) outbreak caused by hospital equipment containing contaminated water: risk factors for infection

Nosocomial outbreaks of urinary tract infections caused by Achromobacter spp. have been rare in recent decades. To identify the origin of an Achromobacter sp. outbreak, conduct multi-modal infection control measures, and finally to stop the outbreak. To this end, an epidemiological outbreak investigation and risk factor analysis were performed. Achromobacter sp. was detected in 22 patients in our urology wards and six environmental cultures of specimens obtained from the operating rooms. Strains isolated were submitted for antimicrobial susceptibility testing. An on-site epidemiological investigation, evaluation of patient medical records, and environmental sampling were performed to identify the source of the outbreak, and implementation of infection control intervention. A case-control study was performed to analyse the potential risk factors. Environmental sampling showed that the source of the infection for 22 patients was an ISA-IIIA-type medical pressurizer containing contaminated water. A case-control analysis showed that the risk factors for infection were: diagnosis of kidney/ureteral stones, surgery, placement of a double-J stent, and history of hospitalization in the past three months. It was concluded that the outbreak occurred in patients who underwent internal lithotripsy and double-J stent placement, due to contact transmission with the contaminated sensor and connecting tubes of the ISA-IIIA-type medical pressurizer.

Generation of spatiotemporal dark pulse or polarization domain wall solitons in a partial multimode mode-locked fiber laser

In this paper, we have experimentally investigated different operational states of a partial multimode Er-doped spatiotemporal mode-locked (STML) fiber laser. The STML is enabled by nonlinear multimode interference (NL-MMI) effect from the partial multimode cavity structure. It is found that by adjusting the multimode polarization controller (PC) and the pump power, the STML dark pulses, bright pulses, as well as the polarization domain wall solitons can all be obtained, alternatively. The fused-tapered multimode coupler is responsible for the dark pulses generation via the enhanced modal cross-phase coupling. It is believed that the present findings can offer an important insight into the spatiotemporal dynamics of the STML solitons.

Multi-Mode Vibration Control of Super-Long Stay Cables with Negative Stiffness and Stockbridge Dampers

Installing mechanical dampers near the cable anchorage is a commonly used measure for suppressing rain-wind-induced vibrations (RWIVs) of stay cables. However, the high-mode vortex-induced vibrations (VIVs) are still observed on super-long stay cables installed with dampers. To this end, the study presents the combination of a negative stiffness damper (NSD) and Stockbridge dampers (SDs) to simultaneously suppress cable RWIVs and VIVs. In the proposed cable–NSD–SDs system, the NSD is installed near the cable anchorage to suppress cable RWIVs, and the SDs are installed at a higher location to suppress cable VIVs. First, the generalized characteristic equation of the cable–NSD–SDs system is derived for computing the coupled damping effect. Subsequently, a novel design method of an NSD and two SDs for mitigating cable multi-mode vibrations is proposed, and its effectiveness is numerically verified on an ultra-long stay cable of the Sutong Bridge. Finally, the control performance of an NSD and two SDs for the cable under white noise and harmonic excitations is emphatically evaluated and compared. Results indicate that the NSD–SDs system is quite effective for mitigating high-mode vibrations of super-long stay cables. Compared with the cable–NSD system, the cable acceleration response of the cable–NSD–SDs system is reduced by over 35%.

Interaction strategy for robotic apology based on human orientation toward service

ABSTRACT In a human–robot symbiotic society, it is crucial to have seamless communication between human and robot. However, there are still numerous obstacles to overcome to develop a interaction system that can flexibly interact in various situations. A practical approach to implementing interaction systems socially is to optimize interaction strategies by limiting and selecting tasks and situations. This research focused on the behavior of ‘apology,’ which is unique to humans and expected to be challenging for robots to replace. Effective interaction strategies were examined, with emphasis on the user's orientation toward the service and the essential elements for a robot to apologize. An apology process was implemented based on specific situations, capable of responding to both utilitarian and relational orientations, along with appropriate multimodal behavior control and speech expressions that consider the user's relationship with the robot. The system with these elements was evaluated for validity and effectiveness in the apology process.

Enhancing Pain Management for Open Inguinal Hernia Repair With a Novel Long-Acting Bupivacaine Drug Device (Xaracoll®) in Multimodal Pain Control: A Quality Improvement Initiative to Reduce Post-Operative Opioid Prescribing.

Background Xaracoll® is a Food and Drug Administration (FDA) approved Type 1 Bovine collagen-based bupivacaine hydrochloride (HCl) implant developed to provide postoperative pain management for up to 24 hours after open inguinal hernia repair in adults. This retrospective review examinedthe efficacy of Xaracoll® in the management of postoperative pain compared to injectable Bupivacaine. Methods This retrospective study examines 54 patients who underwent unilateral open inguinal hernia repair by a single surgeon over three years. The control group consisted of 36 patients who received injectable Bupivacaine as the local anesthetic. Eighteen patients received the Xaracoll® drug device intra-operatively following the FDA-approved manufacturer's guidelines. Intra-operative analgesics administered and quantified by oral morphine equivalents (OME), opioid administration for pain control postoperatively, opioid prescriptions upon discharge, postoperative pain scores, and turnaround time (TAT) were compared. Results The use of Xaracoll® in inguinal hernia repair is associated with a decrease in the rate of opioid administration in the post-anesthesia care unit (PACU) (22.2% vs. 52.8%; p = 0.043). In addition, patients requiring opioids in the outpatient setting needed significantly less OME in the Xaracoll® group compared to the control group (52.50 vs. 136.15; p < .001). Conclusion This study demonstrates compelling evidence that Xaracoll® is a useful analgesia adjuvant for inguinal hernia repair, significantly reducing the need for opioids in the PACU and decreasing doses of opioid medications upon discharge.Xaracoll® is effective in minimizing postoperative pain and opioid medication dosages upon discharge as part of a multimodal approach to pain and improving patient experience. Further research is warranted to evaluate Xaracoll®'s role in pain control in the PACU and on discharge.

Multimode Control Strategy for Robotic Rehabilitation on Special Orthogonal Group SO(3)

Robot-assisted rehabilitation for three-degree-of-freedom joints, such as hip and ankle, is significant for patients with motor function injuries. The control of such robots involves attitude control. To adapt to different disease stages, multi-mode hybrid control is considered to be one of the best choices. Passive mode is based on trajectory tracking control, while active mode is based on field-based assist-as-needed (AAN) control. The key to AAN control is the solution of the closest attitude point. However, the attitude point belongs to a special orthogonal group SO(3), and its topology is completely different from Euclidean space, which causes difficulties to the solution. Both passive and active control methods are affected by the inaccuracy of model parameters and external disturbances. Therefore, this paper proposes a multi-mode hybrid control method on SO(3). First, the expressions of trajectory tracking and contour tracking errors are proposed. To solve the contour tracking error, a feedback linearization algorithm based on sliding surface was used. A radial basis function (RBF) neural network was used for adaptive compensation. Subsequently, a controller for different modes was designed and its stability was analysed. Experiments were conducted using a hip exoskeleton, and the results verified the effectiveness of the proposed control method.

Multi-Mode Control of a Hybrid Transformer for the Coordinated Regulation of Voltage and Reverse Power in Active Distribution Network

The unprecedented growth of distributed renewable generation is changing the distribution network from passive to active, resulting in issues like reverse power flow, voltage violations, malfunction of protection relays, etc. To ensure the reliable and flawless operation of active distribution networks, an electrical device enabling active network management is necessary, and a hybrid distribution transformer offers a promising solution. This study introduces a novel hybrid transformer topology and multi-mode control strategy to achieve coordinated voltage and reverse power regulation in active distribution networks. The proposed hybrid transformer combines conventional transformer windings with a partially rated SiC-MOSFET-based back-to-back converter, reducing additional investment costs and enhancing system reliability. A multi-mode control strategy is proposed to facilitate the concurrent reverse power control and voltage violation mitigation of the presented hybrid transformer, allowing a smooth transition between the P–Q control mode and the V–f control mode. The control mode switching can be activated manually or autonomously in response to voltage violations or reverse power overloading. The effectiveness of the proposed hybrid transformer configuration and its control mode transition mechanism are examined through comprehensive case studies conducted in the PSCAD/EMTDC environment. The proposed HT design has been confirmed to achieve a voltage regulation range of ±20% of the nominal voltage and effectively regulate bidirectional active power flow within a range of −25% to 25% of the rated power.

Distributed control of a plate platform by NES-cells

Nonlinear energy sink (NES) has become a good passive vibration control technique with great potential. For a huge structure, it is unpractical to control the vibration by just one NES, let alone the structure has multi-modes. In this work, a technique who uses distributed nonlinear energy sink cells (NES-cells) to control the multi-modal resonance of the floating raft is proposed. The floating raft is simplified as a corner-point supported plate. Natural modes of it guide the distribution of NES-cells to make NESs locate on the position with strong vibration, which enhances the coupling ship between the plate platform and NES-cells. An example of installing NES-cells guiding by the first-two modes of the corner-point supported plate is presented in this paper. It is compared with the vibration reduction effect by a single NES. To make a fair comparison, total mass of NES-cells is the same with that of the single NES. The results show that NES-cells can deal with multi-modal vibration reduction better. The experimental results also fully illustrate this view. At the same time, the reaction of each NES-cell to the plate is effectively dispersed while comparing with the single NES, which decreases the stress at the attachment points and is more suitable for engineering applications. The number of NES-cells also has an effect on the vibration reduction efficiency. When the design parameters are fixed, there exists an optimal number to make the vibration reduction efficiency tend toward saturation. The multimodal vibration control of the plate platform is effectively solved by the proposed NES-cells technique. It also provides guidance for other practical engineering problems.

Trajectory Deformation-Based Multi-Modal Adaptive Compliance Control for a Wearable Lower Limb Rehabilitation Robot.

Adaptive compliance control is critical for rehabilitation robots to cope with the varying rehabilitation needs and enhance training safety. This article presents a trajectory deformation-based multi-modal adaptive compliance control strategy (TD-MACCS) for a wearable lower limb rehabilitation robot (WLLRR), which includes a high-level trajectory planner and a low-level position controller. Dynamic motion primitives (DMPs) and a trajectory deformation algorithm (TDA) are integrated into the high-level trajectory planner, generating multi-joint synchronized desired trajectories through physical human-robot interaction (pHRI). In particular, the amplitude modulation factor of DMPs and the deformation factor of TDA are adapted by a multi-modal adaptive regulator, achieving smooth switching of human-dominant mode, robot-dominant mode, and soft-stop mode. Besides, a linear active disturbance rejection controller is designed as the low-level position controller. Four healthy participants and two stroke survivors are recruited to conduct robot-assisted walking experiments using the TD-MACCS. The results show that the TD-MACCS can smoothly switch three control modes while guaranteeing trajectory tracking accuracy. Moreover, we find that appropriately increasing the upper bound of the deformation factor can enhance the average walking speed (AWS) and root mean square of trajectory deviation (RMSTD).

High Efficiency Single-phase T-type LCL-filtered Inverter with Multimode Control and Smooth Mode Transition

High Efficiency Single-phase T-type LCL-filtered Inverter with Multimode Control and Smooth Mode Transition

Robustness Evaluation of Negative Stiffness Damper for Cable Vibration Mitigation Based on Interval Model with Experimental Validation

The negative stiffness damper (NSD) has emerged as a promising passive vibration control device for cable structures due to its simplicity and effectiveness. However, uncertainties stemming from both internal and external environmental factors can potentially compromise the NSD’s performance in real‐world applications, posing risks to cable safety. In response, this paper conducts a robustness evaluation on an integrated cable‐NSD system, taking into account various potential uncertainties. Specifically, the uncertain parameters are described by interval variables. Consequently, an interval model is constructed to delineate the boundaries of cable dynamic responses when subjected to these uncertainties. The model’s accuracy is validated against experimental results. Subsequent simulations involve assessing interval responses for both single‐ and multimode cable vibrations under varying uncertainties. Finally, the NSD’s robustness concerning cable vibration control is evaluated using the model, which incorporates the first‐passage theory. This analysis delves into the relationships among confidence levels, performance measures, and the variation range of uncertainties. The results indicate that for single‐mode vibration control, there is a 90% confidence level that the damping ratio reduction remains within 10%. As for multimode vibration control, a 90% confidence level is established that the amplification falls within 17%.

Multimodal Unified Control Method Using the Lie Derivative and Lyapunov Theory for Enhancing the Dynamic Stability of Power Systems With 100% Renewable Energy

Multimodal Unified Control Method Using the Lie Derivative and Lyapunov Theory for Enhancing the Dynamic Stability of Power Systems With 100% Renewable Energy