Torque Reduction Research Articles

Effect of Multiple Grooves on Aerodynamic Performance of a Low Reynolds Number UAV Propeller (Part II)

In an continuation of work previously performed by the author on grooved propellers, numerical investigations are performed on Applied Precision Composites 10×7 Slow Flyer propeller. Computational Fluid Dynamics is used to analyze the novel design. The grooved sections considered have a rectangular geometry measuring 0.1×0.1mm are placed interchangeably at 0.09c, 0.17c, 0.32c and 0.42c from the leading edge in a multi-grooved configuration i.e. more than 2 grooves. The results of the study showed that the presence of grooves had modified the flow characteristics only to detrimentally impact the thrust performance. However, the grooves improved power performance due to torque reduction. The analysis of the results showed that, in most models, low torque relative to the baseline in the operational range of the low to medium advance ratio range exists. The improvement in torque, however, did not improve efficiency in all models.

Spatiotemporal Compliance Control for a Wearable Lower Limb Rehabilitation Robot.

Compliance control is crucial for physical human-robot interaction, which can enhance the safety and comfort of robot-assisted rehabilitation. In this study, we designed a spatiotemporal compliance control strategy for a new self-designed wearable lower limb rehabilitation robot (WLLRR), allowing the users to regulate the spatiotemporal characteristics of their motion. The high-level trajectory planner consists of a trajectory generator, an interaction torque estimator, and a gait speed adaptive regulator, which can provide spatial and temporal compliance for the WLLRR. A radial basis function neural network adaptive controller is adopted as the low-level position controller. Over-ground walking experiments with passive control, spatial compliance control, and spatiotemporal compliance control strategies were conducted on five healthy participants, respectively. The results demonstrated that the spatiotemporal compliance control strategy allows participants to adjust reference trajectory through physical human-robot interaction, and can adaptively modify gait speed according to participants' motor performance. It was found that the spatiotemporal compliance control strategy could provide greater enhancement of motor variability and reduction of interaction torque than other tested control strategies. Therefore, the spatiotemporal compliance control strategy has great potential in robot-assisted rehabilitation training and other fields involving physical human-robot interaction.

Islanding Operation and Seamless Resynchronization in DFIG–SPV System Equipped With Functional Enhancements Through ATLLAD Control Framework

Doubly-fed induction generator (DFIG) and solar photovoltaic (SPV) array equipped hybrid wind-solar generation system is increasingly acknowledged as a viable techno-economic solution for remote-area electrification. Despite the progress made in this frontier, two major hurdles still persist. The first hurdle relates to the power inadequacy for local loads and the mode transitional features in DFIG-SPV system, during grid outages, which are rather frequent in remote-areas. Another issue in DFIG-SPV system at remote-areas is its functional vulnerability at the irregular grid conditions like unbalance and distorted voltages. Taking these aspects into consideration, this paper implements a new arc-tangent least logarithmic absolute difference (ATLLAD) based control framework for DFIG-SPV system. The operational scheme ensures disruption-free load power at islanding scenarios, while, the control strategy enables seamless transitions without inducing overcurrents or voltage spikes during mode switching. To deal with DFIG-side functional vulnerability at irregular grid conditions, ATLLAD-based control uses an innovative approach to impart an additional degree of freedom for the simultaneous suppression of DFIG torque oscillations and reduction in DFIG stator current disturbances. Meanwhile, the enhancement at the grid-side involves injection of improved quality grid currents despite the irregularities in the grid voltages and the load currents. Test results from an experimental-rig of the DFIG-SPV system illustrate satisfactory performance of ATLLAD control approach.

Zeroization of Cogging Torque of Permanent Magnet Machines by Optimizing Rotor Surface Shape: Comparison Between Surface and Interior Types

In this paper, we investigate the mechanism of cogging torque reduction by optimizing the rotor surface of permanent magnet synchronous machines. The optimizations of both the surface and interior permanent magnet machines are carried out. It is clarified that the cogging torques of both the machines can be reduced to be nearly zero by optimizing the rotor surfaces, whereas the mechanisms of cogging torque reduction of these machines are completely different from each other.

Novel Adaptive Magnetic Springs for Reliable Industrial Variable Stiffness Actuation

Parallel elastic actuation is a highly promising concept for assisting preplanned trajectories such as repetitive tasks in industrial machines and robots. Nevertheless, due to the persisting challenges on spring lifetime, its full potential has yet to be leveraged in the industry. We propose a novel adaptive magnetic spring as a fatigue-free spring mechanism to enable variable stiffness actuators in long lifetime applications. The spring is designed to flexibly deal with variations in operating conditions, i.e., mass customization. We propose a co-design methodology which simultaneously optimizes the sizing of the magnetic spring (for the given machine and its operating conditions), together with the controls and ideal dynamic response of the system. This mechanism and the methodology are applied to a design problem of a weaving machine drivetrain, where the benefits of the adaptive magnetic spring are highlighted with respect to a fixed stiffness magnetic spring, and the current industrial benchmark without springs. Experimentally validated findings show a consistent and considerable improvement with respect to energy consumption and peak torque reduction of up to 47% and 64%, respectively, when comparing to the current industrial benchmark.

Combined methods for torque variation reduction of high-speed FSPM

Flux switching permanent magnet machine (FSPM) with six slots and four poles (6/4) shows great potential for high-speed operation. However, the 6/4 FSPM suffers from high cogging torque at no load and loaded torque variation. In this paper, improved analytical model for 6/4 FSPM is derived by means of magnetomotive force and permeance, based on which various methods for cogging torque reduction are analyzed respectively. The two chosen effective methods are combined and a Kriging surrogate model is developed. NSGA-II is adopted to optimize the rotor parameters globally. With combined methods and optimal parameters, the cogging torque of 6/4 FSPM can be largely reduced and the results are verified by finite element analysis (FEA).

Effects of load matched isokinetic versus isotonic blood flow restricted exercise on neuromuscular and muscle function

ABSTRACT The purpose of this investigation was to examine neuromuscular function, muscle fatigue, rating of perceived exertion (RPE), and muscle swelling between isokinetic and isotonic leg extensions with blood flow restriction (BFR). Fourteen (21 ± 2years; 160cm ± 3.8; 61kg ± 9.1) trained women performed 75 (1 × 30,3 × 15) submaximal (30% of maximal strength), unilateral, isokinetic and isotonic leg extensions with BFR (60% of total arterial occlusion pressure). Before and after exercise, subjects performed maximal voluntary isometric contractions (MVIC) and muscle thickness (MT) was assessed with ultrasound. RPE was recorded across all sets and surface electromyography (EMG) was assessed during the MVIC muscle actions. Separate repeated measures ANOVAs were used to examine MVIC, MT, RPE and neuromuscular function. There were greater reductions in MVIC torque and EMG mean power frequency following isotonic (46.2 ± 17.1%; 16.4 ± 7.9%) than isokinetic (17.9 ± 10.9%;6.5 ± 6.3%). RPE was also higher during isotonic (7.5 ± 2.2), than isokinetic (5.7 ± 1.9). There were no differences in EMG amplitude or MT increases (20 ± 2.1%) between conditions. Isotonic BFR elicited greater fatigue-induced decreases in muscular strength and greater RPE than isokinetic BFR, but similar MT and muscle excitation responses for both conditions. Therefore, both isokinetic and isotonic may induce similar acute physiological responses, but isotonic BFR was associated with greater muscle fatigue and perceived effort. Highlights Exercise modality affects the fatigue and perceptual responses when applying blood flow restriction. Despite greater utility, isotonic blood flow restriction was associated greater fatigue and perceived effort. Isotonic and isokinetic blood flow restriction elicited comparable neural changes.

Pole shape design of ring winding axial flux permanent magnet used in a direct‐drive electric boat for cost‐efficient cogging torque alleviation

AbstractThe recently introduced Ring Winding Axial Flux Permanent magnet Motor (RW‐AFPM) is inspired by the yokeless structure of Yokeless and Segmented Armature (YASA) AFPMs and the partitioned‐phases configuration of transverse flux motors. Its potential application for rim‐driven electric ships propulsion has been examined in the previous studies and, here, it will be studied for ultra‐light direct‐drive electric boats. Owing to their specific structural features, the relatively large cogging torque of RW‐AFPMs seems to be a significant challenge for such applications. On the other hand, as investigated in previous studies, cogging torque reduction methods, such as conventional skewing, seem unsuitable for this type of machine. Thus, this paper will address the cogging torque issue via a comprehensive pole shape analysis. The results will be useful for all kinds of partitioned‐phases topologies that have high specific torque capability but suffer from large cogging effects. All analyses are performed via 3D‐FE models, the accuracy of which is pre‐verified through experiments.

An In-Phase Unit Slot-Opening Shift Method for Cogging Torque Reduction in Interior Permanent Magnet Machine

The cogging torque reduction methods in permanent magnet (PM) machines are more or less FEA trial and error-based and cause undesirable side effects, such as distorted back EMF, new harmonic components, and structure asymmetry. A slot-opening grouping method can address these issues. However, it needs to model all slots in FEA design validation during practical cogging torque optimization iterations, and also leads to back-EMF reduction. In this paper, a new grouping strategy, termed in-phase unit (IPU), is introduced, together with the slot-opening angle-shift method. The slot openings with the same cogging torque distribution pattern are grouped into an IPU, and the cogging torque peaks of the slot openings within an IPU can now be interleaved. Thereby, the major harmonic components of the cogging torque are cancelled out, instead of being summed up. The IPU grouping principle, the slot-opening shift angle computation, and the selection of the harmonic order to cancel are analyzed in detail. By comparison, the proposed method not only simplifies cogging torque optimization iterations by only modeling the slots in one IPU in FEA, but also compensates for the back-EMF constant reduction. The effectiveness of the proposed methods is validated by two typical interior PM machine design cases.

Abstract 365: Targeting FGF21 inhibits tumor growth and attenuates cachexia in experimental colorectal cancer

Abstract Background: Colorectal cancer (CRC) is frequently accompanied by cachexia, an uncured multi-organ wasting syndrome, debilitating musculoskeletal health, physical function, and overall survival. Fibroblast growth factor 21 (FGF21) is a modulator of musculoskeletal health and metabolism and has been associated with CRC risk and progression. Here, we investigated the effects of tumor derived FGF21 on musculoskeletal health in CRC. Methods: Plasma from CRC patients and preclinical models of CRC (C26, MC38) were assessed for circulating FGF21 levels, and CRC cell lines (C26, MC38, HCT116) were screened for FGF21 expression. Using CRISPR/Cas9 technology, FGF21 was deleted from MC38 cells (KO-MC38). 8-week-old male C57BL/6J mice were subcutaneously injected (1.0x106) with wild-type (WT-MC38) or FGF21-/- (KO-MC38) MC38 tumor cells, while experimental control animals received saline (n = 10-13/group). Animals underwent electrophysiological testing to obtain motor unit number estimation (MUNE) 48 hours prior to euthanasia and were assessed for maximum plantarflexion torque 24 hours prior to euthanasia. At the time of euthanasia, plasma was collected for assessment of systemic FGF21, while tumors and skeletal muscles (gastrocnemius, quadriceps, and tibialis anterior) were excised and weighed. Femur bones were processed for microcomputed tomography (µCT) imaging and analysis. Results: CRC patients and MC38 tumor hosts demonstrated elevated circulating plasma FGF21 (p<0.05) compared to controls. Gene expression of CRC cells revealed an 11-fold increase of FGF21 in MC38 compared to C26 and HCT116 cells. WT-MC38 tumor hosts had elevated plasma FGF21 (4-fold; p<0.05) compared to control, which was unchanged in KO-MC38 hosts. In line with the development of cachexia, WT-MC38 hosts displayed reductions in muscle mass (gastrocnemius: -5%; p<0.05, quadriceps: -10%; p<0.01, tibialis anterior: -8%; p<0.01), MUNE (-31%; p<0.01), and plantarflexion torque (-10%; p<0.05). Meanwhile, µCT of femur bones demonstrated reductions in trabecular bone volume fraction (BV/TV: -30%; p<0.05) and cortical cross-sectional thickness (Cs.Th: -14%; p<0.05) in WT-MC38 hosts compared to experimental controls. Conversely, when compared to WT-MC38, KO-MC38 hosts had preserved skeletal muscle mass (gastrocnemius: +7%; p<0.01, quadriceps: +13%; p<0.001, tibialis anterior: +8%; p<0.001), MUNE (+47%; p<0.01), plantarflexion torque (+8%; p<0.05), and bone mass (BV/TV: +69%; p<0.001, Cs.Th: +23%; p<0.001). Strikingly, the mass of KO-MC38 tumors was reduced 75% (p<0.01) compared to WT-MC38 tumors. Conclusion: Our data suggest that targeting CRC-derived FGF21 halts tumor growth, resulting in preservation of musculoskeletal health and function. Thus, counteracting tumor-derived FGF21 may serve as a therapeutic intervention against the progression of cancer and cancer-associated cachexia. Citation Format: Fabrizio Pin, Anika Shimonty, Joshua Robert Huot. Targeting FGF21 inhibits tumor growth and attenuates cachexia in experimental colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 365.

Powered Hip Exoskeleton Reduces Residual Hip Effort Without Affecting Kinematics and Balance in Individuals With Above-Knee Amputations During Walking.

A unilateral, lightweight powered hip exoskeleton has been shown to improve walking economy in individuals with above-knee amputations. However, the mechanism responsible for this improvement is unknown. In this study we assess the biomechanics of individuals with above-knee amputations walking with and without a unilateral, lightweight powered hip exoskeleton. We hypothesize that assisting the residual limb will reduce the net residual hip energy. Eight individuals with above-knee amputations walked on a treadmill at 1 m/s with and without a unilateral powered hip exoskeleton. Flexion/extension assistance was provided to the residual hip. Motion capture and inverse dynamic analysis were performed to assess gait kinematics, kinetics, center of mass, and center of pressure. The net energy at the residual hip decreased from 0.05±0.04 J/kg without the exoskeleton to -0.01±0.05 J/kg with the exoskeleton (p = 0.026). The cumulative positive energy of the residual hip decreased on average by 18.2% with 95% confidence intervals (CI) (0.20 J/kg, 0.24 J/kg) and (0.16 J/kg, 0.20 J/kg) without and with the exoskeleton, respectively. During stance, the hip extension torque of the residual limb decreased on average by 37.5%, 95% CI (0.28 Nm/kg, 0.36 Nm/kg), (0.17 Nm/kg, 0.23 Nm/kg) without and with the exoskeleton, respectively. Powered hip exoskeleton assistance significantly reduced the net residual hip energy, with concentric energy being the main contributor to this change. We believe that the reduction in residual hip extension torque during early stance is the main contributor to this reduction. This analysis shows that by assisting the residual hip, the exoskeleton significantly decreased the net hip energy produced by the residual limb, which may explain the improvements in walking economy previously observed.

Surrogate-assisted multi-objective optimization for control parameters of adjacent gearshift process with multiple clutches

The limited sensors in mass-produced automatic transmissions introduce a significant challenge for performing gearshifts with multiple clutches. To tackle this challenge, this study proposes an integrated surrogate-assisted multi-objective optimization (ISAMO) framework to obtain the optimal control profiles. An optimization-oriented gearshift control strategy coordinated with engine torque reduction is proposed for the gearshift process with four active clutches. A multi-objective optimization problem is formulated to determine the optimal parameters of the proposed control strategy. To mitigate the excessive computation required by the iterative simulation of the physical model in the multi-objective optimization process, we construct a surrogate model to substitute for the physical model based on a radial basis function neural network (RBFNN) and an adaptive sampling method. The RBFNN surrogate model is used in conjunction with the non-dominated sorting genetic algorithm (NSGA-II) to obtain the Pareto optimal set. The improved radar chart evaluation method is adopted to determine an optimal trade-off solution in the Pareto optimal set. The shift transitions of the optimal trade-off solution are simulated and analyzed. Results validate the effectiveness of the proposed ISAMO framework in improving optimization efficiency without sacrificing accuracy.

Effects of neurorehabilitation with and without dry needling technique on muscle thickness, reflex torque, spasticity and functional performance in chronic ischemic stroke patients with spastic upper extremity muscles: a blinded randomized sham-controlled clinical trial

Purpose Evaluation the effects of dry needling on sonographic, biomechanical and functional parameters of spastic upper extremity muscles. Methods Twenty-four patients (35–65 years) with spastic hand were randomly allocated into two equal groups: intervention and sham-controlled groups. The treatment protocol was 12-sessions neurorehabilitation for both groups and 4-sessions dry needling or sham-needling for the intervention group and sham-controlled group respectively on wrist and fingers flexor muscles. The outcomes were muscle thickness, spasticity, upper extremity motor function, hand dexterity and reflex torque which were assessed before, after the 12th session, and after one-month follow-up by a blinded assessor. Results The analysis showed that there was a significant reduction in muscle thickness, spasticity and reflex torque and a significant increment in motor function and dexterity in both groups after treatment (p < 0.01). However, these changes were significantly higher in the intervention group (p < 0.01) except for spasticity. Moreover, a significant improvement was seen in all outcomes measured one-month after the end of the treatment in the intervention group (p < 0.01). Conclusions Dry needling plus neurorehabilitation could decrease muscle thickness, spasticity and reflex torque and improve upper-extremity motor performance and dexterity in chronic stroke patients. These changes were lasted one-month after treatment.Trial Registration Number: IRCT20200904048609N1 IMPLICATION FOR REHABILITATION Upper extremity spasticity is one of the stroke consequences which interfere with motor function and dexterity of patient hand in activity of daily living Applying the dry needling accompanied with neurorehabilitation program in post-stroke patients with muscle spasticity can reduce the muscle thickness, spasticity and reflex torque and improve upper extremity functions

Effect of different laser texturing patterns on rolling contact surface and its tribological & fatigue life behavior on 100Cr6 bearing steel

The effects of laser texturing technology on the tribological performance of tapered roller bearings in terms of fatigue life, friction, and wear are studied for the first time. The influence of diameter, height and density of the circular-shaped dimples is thoroughly analyzed, first on flat samples, and the most encouraging results are upscaled to components. This research demonstrates the advantages that surface texturing can bring to the most demanding applications involving rolling surfaces under lubrication regime. The experiments show a torque reduction up to 18% and very promising results in fatigue life tests.

Slot opening displacement technique for cogging torque reduction of axial flux brushless DC motor for electric two-wheeler application

Introduction. Reduction of cogging torque is the crucial design consideration of axial flux brushless DC (BLDC) motor, particularly for low-speed applications. Aim. The slot opening displacement technique is presented in this article to reduce cogging torque in axial flux BLDC motors suitable for electric two-wheeler applications. Methods. Double rotor single stator configuration of axial flux BLDC motor is the most suitable for such vehicular applications. Initially double rotor single stator 250 W, 150 rpm axial flux BLDC motor is designed with stator slot opening in middle position and considered as reference motor for further analysis. To evaluate the cogging torque profile of the reference motor 3D finite element modeling and analysis are performed. The design is enhanced by dividing all stator teeth into groups and displacing the slot openings of each group in opposite direction with respect to the adjacent group. Results. The influence of slot opening displacement on cogging torque is evaluated with finite element modeling and analysis. As cogging torque is reduced from 1.23 N×m to 0.63 N×m, the slot opening displacement technique is found to be effective in reducing cogging torque of axial flux BLDC motor.

Utilizing the RPE-Clamp model to examine interactions among factors associated with perceived fatigability and performance fatigability in women and men.

The purpose of the present study was to examine the interactions between perceived fatigability and performance fatigability in women and men by utilizing the RPE-Clamp model to assess the fatigue-induced effects of a sustained, isometric forearm flexion task anchored to RPE = 8 on time to task failure (TTF), torque, and neuromuscular responses. Twenty adults (10 men and 10 women) performed two, 3s forearm flexion maximal voluntary isometric contractions (MVICs) followed by a sustained, isometric forearm flexion task anchored to RPE = 8 using the OMNI-RES (0-10) scale at an elbow joint angle of 100°. Electromyographic amplitude (EMG AMP) was recorded from the biceps brachii. Torque and EMG AMP values resulting from the sustained task were normalized to the pretest MVIC. Neuromuscular efficiency was defined as NME = normalized torque/normalized EMG AMP. Mixed factorial ANOVAs and Bonferroni corrected dependent t tests and independent t tests were used to examine differences across time and between sex for torque and neuromuscular parameters. There were no differences between the women and men for the fatigue-induced decreases in torque, EMG AMP, or NME, and the mean decreases (collapsed across sex) were 50.3 ± 8.6 to 2.8 ± 2.9% MVIC, 54.7 ± 12.0 to 19.6 ± 5.3% MVIC, and 0.94 ± 0.19 to 0.34 ± 0.16, respectively. Furthermore, there were no differences between the women and men for TTF (251.8 ± 74.1vs.258.7 ± 77.9s). The results suggested that the voluntary reductions in torque to maintain RPE and the decreases in NME were likely due to group III/IV afferent feedback from peripheral fatigue that resulted in excitation-contraction coupling failure.

Analysis and Suppression of Cross-Coupling Demagnetization in Dual Permanent Magnet Machine for Direct-Drive Application

Dual permanent magnet (PM) machines synthesize two PM excitations together and potentially exhibit higher torque density than conventional single-PM excited machines. In dual-PM excited machines, the existence of one PM excitation tends to cause interior flux density reduction and irreversible demagnetization of the other PM set, and this feature is recognized as cross-coupling demagnetization. Therefore, this article systematically analyzed the mechanism and influence of this unique phenomenon in a dual-PM prototype machine. The results reveal that the cross-coupling demagnetization can result in up to 18% torque reduction under a severe working conditions if the machine is not properly designed. Increasing one set of PM thickness along the magnetization direction is beneficial to enhance the self-demagnetization withstanding ability, whereas the cross-coupling demagnetization on the other PM set has deteriorated. In order to eliminate such a side effect, some techniques, e.g., removing the demagnetization region and alleviating the mutual flux path, are presented to suppress the demagnetization. It is revealed that the demagnetization rate can be reduced to less than 3% with proper design. Finally, a dual-PM prototype is manufactured and tested to validate the improvement of demagnetization withstanding capability by using the presented suppression technique.

고정자 비대칭 Tooth Tip과 회전자 Step Skew를 조합한 표면형 영구자석 모터의 코깅 토크 저감 설계

코깅 토크 저감은 높은 정밀 구동이 필요한 모터의 중요한 성능 인자이다. 따라서, 코깅 토크 저감을 위해 고정자 또는 회전자에 스큐가 주로 적용된다. 그러나, 스큐 방식은 제조 비용 증가하며, 이로 인해 의도치 않은 성능 열화가 나타나는 단점이 있다. 본 논문은 기존의 스큐 방식을 대신하여, 코깅 토크 및 토크리플 저감을 위해 회전자의 스큐 및 고정자의 비대칭 Tooth Tip를 적용한 설계를 제안한다. 연구 대상은 4단 step-skew를 적용한 기존의 회전자 모델에 대해, 2단 step skew를 적용한 회전자 및 비대칭 tooth tip을 적용한 모델이다. 제안 모델를 검증하기 위해, 유한요소법을 이용하여 코깅 토크, 역기전력 및 토크 리플을 비교한다.

Design and optimisation of energy‐efficient PM‐assisted synchronous reluctance machines for electric vehicles

AbstractThe design and optimisation of a permanent magnet‐assisted synchronous reluctance (PMaSynR) traction machine is described to improve its energy efficiency over a selection of driving cycles, when installed on a four‐wheel‐drive electrically powered vehicle for urban use, with two on‐board powertrains. The driving cycle‐based optimisation is defined with the objective of minimising motor energy loss under strict size constraints, while maintaining the peak torque and restricting the torque ripple. The key design parameters that exert the most significant influence on the selected performance indicators are identified through a parametric sensitivity analysis. The optimisation brings a motor design that is characterised by an energy loss reduction of 8.2% over the WLTP Class 2 driving cycle and 11.7% over the NEDC and Artemis Urban driving cycles, at the price of a 4.7% peak torque reduction with respect to the baseline machine. Additional analysis, implemented outside the optimisation framework, revealed that different coil turn adjustments would reduce the energy loss along the considered driving cycles. However, under realistic size constraints, the optimal design solutions are the same.

Modeling and Investigation of the Velocity-Dependent Cutting Process with PDC Cutters Using the Discrete Element Method

Polycrystalline diamond compact (PDC) bits with multiple fixed cutters drill through deep formations and are used in oil and gas, geothermal, and mining industry. The bit-rock interaction excites drill string vibrations, which need to be mitigated to improve drilling performance. A velocity-weakening characteristic of the bit torque can cause severe self-excited high-frequency torsional oscillations (HFTO) of the bottom hole assembly (BHA). The dependency on velocity can be attributed to rate-sensitive rock cutting forces at each cutter. The purpose of this paper is to model the rate effect of cutting forces and determine influencing factors in the single-PDC cutting process. In this paper, a modified bonded-particle model (discrete element method, DEM) for rock in deep drilling environments is applied to the pressurized cutting process. Potential modification strategies considering rate indicators at different scales are compared and discussed to reproduce rate dependency in the particle contact model. Two specific models, incorporating cutting-speed-dependent bond strength or grain elastoplasticity, are implemented and verified. The relationship between rate-sensitive cutting forces and the causal rock failure mechanisms is then clarified by interpreting the results from a continuum perspective. Moreover, the influences of axial force and cutter wear state on the rate dependency are investigated. In cutting simulations at a constant depth of cut and various cutting speeds, both models result in rate-dependent cutting forces in good qualitative agreement with rock experiments: Significant hardening is reflected in the axial force component. The modification of contact models combined with a macroscopic rate indicator (i.e. cutting speed) has proven to be a feasible and effective way to reproduce the rate effects in the cutting simulations. In subsequent simulations with constant axial force, the steady-state tangential force decreases as the cutting speed increases, matching the reduction of torque on the bit with increasing RPM. Rate dependency intensifies at higher axial forces or with dull cutters, which agrees with laboratory full-scale bit tests in the literature. This study proposes a practical approach to integrating observed rate effects of downhole rock cutting processes into numerical rock models. The results enhance our understanding of the rock cutting process and have positive implications for the improvement of the cutter design against undesirable rate effects.