Changes In Torque Research Articles

Reliability and minimal detectable change of stiffness and other mechanical properties of the ankle joint in standing and walking

BackgroundAnkle joint stiffness and viscosity are fundamental mechanical descriptions that govern the movement of the body and impact an individual’s walking ability. Hence, these internal properties of a joint have been increasingly used to evaluate the effects of pathology (e.g., stroke) and in the design and control of robotic and prosthetic devices. However, the reliability of these measurements is currently unclear, which is important for translation to clinical use. Research questionCan we reliably measure the mechanical impedance parameters of the ankle while standing and walking? MethodsEighteen able-bodied individuals volunteered to be tested on two different days separated by at least 24 h. Participants received several small random ankle dorsiflexion perturbations while standing and during the stance phase of walking using a custom-designed robotic platform. Three-dimensional motion capture cameras and a 6-component force plate were used to quantify ankle joint motions and torque responses during normal and perturbed conditions. Ankle mechanical impedance was quantified by computing participant-specific ensemble averages of changes in ankle angle and torque due to perturbation and fitting a second-order parametric model consisting of stiffness, viscosity, and inertia. The test-retest reliability of each parameter was assessed using intraclass correlation coefficients (ICCs). We also computed the minimal detectable change (MDC) for each impedance parameter to establish the smallest amount of change that falls outside the measurement error of the instrument. ResultsIn standing, the reliability of stiffness, viscosity, and inertia was good to excellent (ICCs=0.67–0.91). During walking, the reliability of stiffness and viscosity was good to excellent (ICCs=0.74–0.84) while that of inertia was fair to good (ICCs=0.47–0.68). The MDC for a single subject ranged from 20%− 65% of the measurement mean but was higher (>100%) for inertia during walking. SignificanceResults indicate that dynamic measures of ankle joint impedance were generally reliable and could serve as an adjunct clinical tool for evaluating gait impairments.

Novel Composite Speed Control of Permanent Magnet Synchronous Motor Using Integral Sliding Mode Approach

Permanent magnet synchronous motors (PMSMs) are widely applied in industry, and proportional integral (PI) controllers are often used to control PMSMs. Aiming at the characteristics of the poor anti-disturbance ability and speed ripple of traditional PI controllers, a novel composite speed controller for PMSMs is proposed in this paper that uses a novel sliding mode control (SMC). To improve the chattering problem of traditional SMC, a high-order approaching law super-twisting algorithm (STA) is applied. Considering the internal and external disturbance of motor driver systems, such as motor parameter drifts and load torque changes, a disturbance estimator based on an extended state observer (ESO) is proposed, and it is used for the feed-forward compensation of the current. The composite super-twisting integral sliding mode controller (ST-ISMC) with a nonlinear ESO is tested by simulations and experiments, and the comparative results verify that the proposed controller has the higher control accuracy, smaller speed ripple and stronger robustness.

Trajectory Smoothing Planning of Delta Parallel Robot Combining Cartesian and Joint Space

Delta parallel robots have been widely used in precision processing, handling, sorting, and the assembly of parts, and their high efficiency and motion stability are important indexes of their performance.Corners created by small line segments in trajectory planning cause abrupt changes in a tangential discontinuous trajectory, and the vibration and shock caused by such changes seriously affect the robot’s high-speed and high-precision performance. In this study, a trajectory-planning method combining Cartesian space and joint space is proposed. Firstly, the vector method and microelement integration method were used to establish the complete kinematic and dynamic equations of a delta parallel robot, and an inverse kinematic/dynamic model-solving program was written based on the MATLAB software R2020a. Secondly, the end-effector trajectory of the delta parallel robot was planned in Cartesian space, and the data points and inverse control points of the end effector’s trajectory were obtained using the normalization method. Finally, the data points and control points were mapped to the joint space through the inverse kinematic equation, and the fifth-order B-spline curve was adopted for quadratic trajectory planning, which allowed the high-order continuous smoothing of the trajectory planning to be realized. The simulated and experimental results showed that the trajectory-smoothing performance in continuous high-order curvature changes could be improved with the proposed method. The peak trajectory tracking error was reduced by 10.53%, 41.18%, and 44.44%, respectively, and the peak torque change of the three joints was reduced by 3.5%, 11.6%, and 1.6%, respectively.

Dynamic response of a pump-turbine runner during turbine's mode starting up

With an increase in head and rotational speed, pumped storage units, particularly the runner, experience higher pressure and centrifugal force. In this study, a combination of the 1D method of characteristics (MOC), 3D computational fluid dynamics (CFD) as well as computational structure dynamics (CSD) was employed to examine the dynamic response of a pump turbine runner during turbine's mode starting up. A detailed analysis of the transient characteristics during this process was conducted. Initially, the high-pressure zone concentrated on the pressure surface of the runner's inlet side. However, this zone gradually expanded over time and shifted to the suction surface. The time-frequency of pressure pulsation showed significant low-frequency and second harmonic frequency components. Different monitoring points exhibited different sensitivities to rotational speed and torque. It can be assumed that runner's blade stress is proportional to the square of the rotational speed. The sensitivity of blade stress related to runner speed and torque provides important results and analysis. P2 is the most sensitive to changes in rotational speed, while P1 is the most sensitive to changes in torque. These findings enhance our understanding of the dynamic behavior of the RPT runner and contribute to potential improvements in design and operation.

Impact-aware task-space quadratic-programming control

Robots usually establish contacts at rigid surfaces with near-zero relative velocities. Otherwise, impact-induced energy propagates in the robot’s linkage and may cause irreversible damage to the hardware. Moreover, abrupt changes in task-space contact velocity and peak impact forces also result in abrupt changes in robot joint velocities and torques; which can compromise controllers’ stability, especially for those based on smooth models. In reality, several tasks would require establishing contact with moderately high velocity. We propose to enhance task-space multi-objective controllers formulated as a quadratic program to be resilient to frictional impacts in three dimensions. We devise new constraints and reformulate the usual ones to be robust to the abrupt joint state changes mentioned earlier. The impact event becomes a controlled process once the optimal control search space is aware of: (1) the hardware-affordable impact bounds and (2) analytically computed feasible set (polyhedra) that constrain post-impact critical states. Prior to and nearby the targeted contact spot, we assume, at each control cycle, that the impact will occur at the next iteration. This somewhat one-step preview makes our controller robust to impact time and location. To assess our approach, we experimented its resilience to moderate impacts with the Panda manipulator and achieved swift grabbing tasks with the HRP-4 humanoid robot.

Research on Collaborative Control of Differential Drive Assisted Steering and Active Front Steering for Distributed Drive Electric Vehicles

A collaborative control strategy for distributed drive electric vehicles (DDEVs) focusing on differential drive assisted steering (DDAS) and active front steering (AFS) is proposed to address the issues of sudden torque changes, reduced steering characteristics, and weak collaborative control capabilities caused by the coupling of the AFS and DDAS systems in DDEVs. This paper establishes a coupled dynamic model of the AFS and DDAS systems and, on this basis, designs AFS controllers for yaw velocity feedback control and DDAS controllers for steering wheel torque control, respectively. Additionally, it analyzes the interference factors of the two control systems and develops a collaborative control strategy for DDAS and AFS; this control strategy establishes a corner motor correction module, steering wheel torque correction module, and assistance correction module. Co-simulation is carried out on Matlab/Simulink and the Carsim platform to verify the correctness of the model under typical working conditions; to reduce the sudden change in the steering wheel torque caused by AFS additional angle interventions; to improve the poor steering characteristics caused by DDAS, introducing additional yaw torque; to greatly enhance the collaborative control effect; and to meet the requirements for vehicle handling stability, portability, and safety.

Optimal mode movement of the robot manipulator on an elastic base according to the criterion of the mean square value of the acceleration of the drive torque

Previous studies of the optimization of the manipulator motion mode on an elastic base based on the criteria of the rms value of the drive torque and the rate of change of the rms value of the drive torque established that the use of optimal manipulator motion modes, which are created on the basis of higher derivatives of the characteristics of the change of the drive torque, allow to obtain more smooth movements of the boom system of the manipulator, thereby reducing its oscillations on the elastic support. At the same time, the obtained optimal modes of movement didn't completely eliminate the boom system oscillations during the change of departure. By observing the oscillations of the elastic link of the manipulator, the quality of the obtained optimal modes of movement was evaluate and the presence of residual oscillations was shown.
 This work considers the possibility of optimizing the manipulator's motion mode based on the criterion of the mean square value of the acceleration of the drive torque change. For this purpose, the second derivative of the driving torque function of the manipulator boom system drive was determined first. Such a criterion for optimizing the motion mode is an integral functional, the minimization of which is carry out by the methods of variational calculus. The regularity of the change of the driving torque it was find from the dynamic equation of motion.
 The search for the optimal motion mode of the manipulator realized through the solution of the Poisson boundary nonlinear differential equation of the fourth order.
 The results of the conducted research made it possible to clarify much better the nature of the vibrations of the manipulator boom system and, as a result, to develop a drive control system that allows the realization of the obtained optimal mode of movement.

Relative attitude stability analysis of double satellite formation for gravity field exploration in space debris environment

Spacecraft operating in low orbit are at risk of being hit by space debris. In the debris environment, the impact of debris is likely to cause the double satellite formation to exit science mode or even lead to the divergence of the control system, thus affecting the scientific exploration mission. In this paper, the attitude stability of the double satellite formation for gravity field in the near circular and polar orbit in the space debris environment is studied. Firstly, based on Lyapunov control and LQR, two sets of control models of stochastic collision for two satellites aligned with each other were proposed, and the actuators were modelled and assigned. Secondly, models of collision probability and momentum are developed. The distribution law of space debris is obtained according to the international common debris software. Meanwhile, probability density function of two independent collisions is gained. Finally, through Monte Carlo simulation and statistics, the changes of relative attitude and thrust torque are simulated when the satellite obtains the angular momentum for a short period of time due to being impacted by space debris. During the 10-year mission period, the number of times that the space debris impact makes the satellite attitude out of the science mode and the number of times that the control system diverges are obtained, which provides a reference for the normal manner of the double satellite formation for gravity field exploration.

Analysis of the results of physical and mechanical experimental studies of the modernized belt conveyor

The article presents a diagram of a modernized design of a belt conveyor with composite guide rollers with elastic elements. A complex experimental technique is given. The patterns of changes in torques and angular velocities of the belt conveyor drums are obtained. The patterns of oscillations of the outer sleeve of the composite rollers of the conveyor guide are determined. Based on the analysis of the constructed profile substitutions their recommended values are determined which ensure high performance with minimal values of the friction force.

Influence of hydrodynamic retarder blade angle on vortex structure

The internal flow of the hydrodynamic retarder cavity is a complex three-dimensional turbulent flow, and the evolution of vortices in its internal two-phase flow field is closely related to the generation of braking torque and the dissipation of kinetic energy. In this study, a periodic flow channel model is used to investigate the influence of different blade angles on vortex structure characteristics. The vortex structure identification method with Q criterion is employed to compare and analyze the distribution and development of the vortex structure. Particle image velocimetry (PIV) tests are conducted to observe the evolution of the vortex structure inside the retarder and validate the simulation analysis. Results show that the increase of the vortex structure scale, intensity, and transformation speed caused by the increase of the blade angle, which affects the energy dissipation and transfer of the flow field and explains the reason for the change of the braking torque. This provides a theoretical basis for the study of the braking performance mechanism and design optimization of the hydrodynamic retarder.

Adaptations in Gait Mechanics When Walking in an Ankle Exoskeleton

Exoskeletons are robotic, brace-like devices that can apply assistive torques to joints, supplementing biological torques. For example, ankle exoskeletons are often designed to assist during the push-off phase of walking to reduce energy expenditure. However, the mechanism by which these exoskeletons reduce metabolic costs is often unclear due to complex human-machine interactions. Here, our purpose was to determine what lower-limb gait kinematic, kinetic, and muscle activity changes underly metabolic cost reductions during ankle exoskeleton-assisted walking. We had healthy participants (n=6) perform two, 12-minute walking trials, one without assistive torques applied (Exo Off) and one with assistive torques applied (Exo On). Participants walked on a force plate instrumented treadmill (Bertec) and were instrumented with optical motion capture (Qualisys) to measure lower-limb gait kinematics and kinetics using Opensim, electromyography (Delsys) to measure the muscle activity of nine lower-limb muscles of the dominant limb, and indirect calorimetry (Cosmed) to measure metabolic energy expenditure (Figure 1A). We aggregated the motion capture, electromyography, and metabolic data for a final analysis using custom scripts (Matlab). We found that metabolic energy expenditure was reduced by 9.52  1.25% (p=0.011; Figure 1B). This, however, did not coincide with any changes in biological ankle angle, torque, or power. However, there was a trending reduction in peak soleus activity (p=0.052). Surprisingly, we did find a reduction in knee power (p=7.3x10-3; Figure 1C) and an accompanying decrease in semitendinosus activity (p=5.9x10-3). Despite the exoskeleton acting at the ankle joint, we found the clearest benefits at the knee joint—highlighting that complex, multi-joint adaptations may underly cost savings. We are continuing data collection to increase our statistical power and better understand the mechanisms that underly exoskeleton assistance.

Sliding Mode Control for Sensorless Speed Tracking of PMSM with Whale Optimization Algorithm and Extended Kalman Filter

This paper proposes a sensorless speed control strategy for a permanent magnet synchronous motor system. Sliding mode control with a whale optimization algorithm was developed for robustness and chattering reduction. To estimate the position and speed of the rotor, an extended Kalman filter using Gaussian process regression was designed. In this controller, the whale optimization method adjusts the switching gain to minimize the tracking error. However, it provides chattering reduction and robustness, owing to the adaptive gain. The extended Kalman estimator calculates the rotor speed by using the current and voltage of the motor as an observer. The observer ensures the high reliability and low cost of the controller. The noise covariance and weight matrices that validated the performance of the estimation were optimized using a regression algorithm. The Gaussian process regression was trained to approximate the best covariance and matrices from the results of the motor controller execution. The performance of the proposed method was demonstrated through simulations under several conditions of tracking speed and load torque changes.

An Efficient and High-Precision Electromagnetic–Thermal Bidirectional Coupling Reduced-Order Solution Model for Permanent Magnet Synchronous Motors

The traditional electromagnetic–thermal bidirectional coupling model (EMTBCM) of permanent magnet synchronous motors (PMSMs) requires a long time to solve, and the temperature-induced torque change is not accounted for in the finite element (FE) numerical calculation of the EM field. This paper presents a precise and efficient EMTBC reduced-order solution model. The specific methods are as follows: First, a torque control technology based on the current injection method is proposed for determining the effect of temperature on the properties of EM materials and EM torque in an EM field, and the accuracy of the FE numerical calculation model is improved. Second, we use the improved EM field finite element numerical calculation model (FEMNCM) to analyze the correlation between the EM loss, the temperature, and the load, and we replace the FEMNCM with the EM field reduction model using the least-squares method. Then, we analyze the law of the PMSM’s internal temperature distribution. We choose the GA-BP algorithm with as few samples as possible and a high accuracy and stability to build the regression prediction model of the temperature field. We use this regression prediction model to replace the complex temperature field calculation. After analyzing the EMTBCM solution strategy, the original complex EMTBC numerical calculation model is substituted with iterations of the magnetic field reduction model and the temperature field regression prediction model. The FE numerical calculation is then used to validate the reduced-order model. The proposed model is validated through numerical simulations. The numerical results indicate that the proposed reduced-order EMTBC model in this paper is accurate and computationally efficient.

Experimental Study on HMCVT Adaptive Control of Cotton Pickers

Aiming at the stability of the output speed and the poor adaptability of the transmission system during the operation of a cotton picker, a control strategy of hydro-mechanical continuously variable transmission (HMCVT) for cotton pickers based on gray prediction and fuzzy PID is proposed. Firstly, the hardware and software of the existing hydraulic mechanical coupling transmission test-bed of cotton pickers are designed, and the HMCVT human-computer interaction measurement and control system is built by using LABVIEW 2020 software. Then, combined with the transmission theory, the control strategy and gray prediction model are designed. Finally, the continuity test, transmission efficiency test, and adaptive control verification test are carried out. The results show that as the input speed increases, the peak time of the pump motor output speed is prolonged, while the overall speed regulation process is smoother, and the output speed process of the HMCVT system is continuous. As the displacement ratio of the variable pump increases, the transmission efficiency of the hydraulic system increases accordingly, but the highest efficiency is around 0.8. At a working speed of 10 km/h, the transmission efficiency of the HMCVT system of the cotton picker is more than 80%, and the high efficiency of the mechanical system in the whole system makes up for the low efficiency of the hydraulic system, and the transmission efficiency of the cotton picker is the highest at 15–25 km/h. The speed under the adaptive control strategy is better, with good robustness to sudden torque changes and speed fluctuations in the range of ±0.0125% under external load conditions. This study provides a reference for future adaptive control of transmission output speed for heavy-duty vehicles and construction machinery.

DC-link voltage balancing and control of qZ-source inverter fed induction motor drive

<span lang="EN-US">Poor performance of the motor drive system is caused when the direct current-link (DC-link) capacitor voltages of the inverter are not sufficiently generated. This is mainly because of the various load torque changes and input voltage fluctuation. The qZ-source inverter operates with a fully shoot-through technique. This technique causes mismatching between the upper and lower DC-link capacitor voltages. Without capacitor voltage-balancing function, the desired DC-link capacitor voltages could not be provided or maintained when there are load and speed changes. A Sawtooth carrier-based simple boost triple-sixty-degree (TSD) pulse width modulation (PWM) technique is used to drive the qZ-source T-type inverter because this technique can give a more significant boost DC-link voltage than a traditional simple boost PWM technique. Proportional integral (PI) controller is applied for the DC-link voltage controller to achieve the fast response and less steady-state error. The simulation model was constructed for a 4 kW, 400 V, 1,400 rpm induction motor (IM) drive system used in rolling mill using MATLAB/Simulink with and without voltage balancing function. As a result, DC-link voltages of the qZ-source T-type inverter fed the induction motor drive system could be controlled using a capacitor voltage-balancing function and the output power of the motor from the simulation result is approximately equal to 4 kW.</span>

Compensation of NI Behaviors in Synchronous Motors With NI HTS Field Winding Using Harmonic Current Injection

Focusing on the improved operation reliability of no-insulation (NI) high-temperature superconductor (HTS) coils, various attempts are being conducted to replace conventional superconductor coils with NI HTS coils for industrial and energy conversion purposed applications. When applying NI techniques, unique behaviors of NI HTS coils due to the removal of turn-to-turn insulation should be considered with given operating conditions, because it could affect the overall characteristics of the machines. In particular, in the case of synchronous motors to which NI HTS field winding is adopted, it has been reported that periodic turn-to-turn leak currents were identified even in steady-state operation due to harmonic components, which may result in torque and loss characteristics changes. Here we report a method to offset these additional NI behaviors that may appear when NI HTS field winding is applied to synchronous motors. A brief mechanism of the proposed method was presented, and the proposed method was applied to an example model through finite element analysis. As a result, it was shown that turn-to-turn contact loss could be reduced to 2.18% without adverse effect on torque characteristics.

The Anterior Fibers of the Superficial MCL and the ACL Restrain Anteromedial Rotatory Instability

Background: There is limited knowledge about how the anterior cruciate ligament (ACL) and capsuloligamentous structures on the medial side of the knee act to control anteromedial rotatory knee instability. Purpose: To investigate the contribution of the medial retinaculum, capsular structures (anteromedial capsule, deep medial collateral ligament [MCL], and posterior oblique ligament), and different fiber regions of the superficial MCL to restraining knee laxity, including anteromedial rotatory instability. Study Design: Controlled laboratory study. Methods: Eight fresh-frozen human cadaveric knees were tested using a 6 degrees of freedom robotic testing system in a position-controlled mode. Loads of 10 N·m valgus rotation, 5 N·m tibial external rotation, 5 N·m tibial internal rotation, and 134 N anterior tibial translation in 5 N·m external rotation were applied at different flexion angles. The motion of the intact knee at 0° to 120° of flexion was replicated after sequential excision of the sartorial fascia; anteromedial retinaculum; anteromedial capsule; anterior, middle, and posterior fibers of the superficial MCL; the deep MCL; the posterior oblique ligament; and the ACL. The reduction in force/torque indicated the contribution of each resected structure to resisting laxity. A repeated-measures analysis of variance with a post hoc Bonferroni test was used to analyze the relative force and torque changes from the intact state. Results: The superficial MCL was the most important restraint to valgus rotation from 0° to 120° and provided the largest contribution to resisting external rotation between 30° and 120° of knee flexion, gradually increasing from 25.2% ± 7.4% at 30° to 36.9% ± 15.4% at 90°. The posterior oblique ligament contributed significantly to resisting valgus rotation only in extension (17.2% ± 12.1%) but was the major restraint to internal rotation at 0° (46.7% ± 13.1%) and 30° (30.4% ± 17.7%) of flexion. The sartorial fascia and anteromedial retinaculum resisted ER at all knee flexion angles (P < .05) and was the single most important restraint in the extended knee (19.5% ± 11%). The capsular structures (anteromedial capsule and deep MCL) had a combined contribution of 20% ± 11.5% at 0° and 23.4% ± 10.5% at 120° of knee flexion but were less important from 30° to 90°. The ACL was the primary restraint to anterior tibial translation in external rotation between 0° and 60° of flexion (50.2% ± 16.9% at 30°), but the superficial MCL was more important at 90° to 120° of knee flexion (36.8% ± 16.4% at 90°). The anterior, middle, and posterior regions of the superficial MCL contributed differently to the simulated laxity tests. The anterior fibers were the most important part of the superficial MCL in resisting external rotation and combined anterior tibial translation in external rotation. Conclusion: The superficial MCL not only was the primary restraint to valgus rotation throughout the range of knee flexion but also importantly contributed to resisting anterior tibial translation in external rotation, particularly in deeper flexion in the cadaveric model. The anterior fibers of the superficial MCL are the most important superficial MCL fibers in resisting anterior tibial translation in external rotation. This study suggests that a medial reconstruction that reproduces the function of the posterior MCL fibers and posterior oblique ligament may not best control anteromedial rotatory instability. Clinical Relevance: Based on these data, there is a need for an individualized medial reconstruction to address different types of medial injury patterns and instabilities.

Weekly minimum frequency of one maximal eccentric contraction to increase muscle strength of the elbow flexors.

Our previous study showed that one 3-s maximal eccentric contraction a day performed 5 days a week for 4 weeks (5DW) increased maximal voluntary contraction (MVC) strength of the elbow flexors more than 10%. The present study examined whether muscle strength would still increase when the frequency was reduced to 2 days or 3 days per week. Twenty-six healthy young adults were recruited in the present study and placed to two groups (n = 13/group) based on the weekly frequency of the one 3-s maximal eccentric contraction for two (2DW) or three days per week (3DW) for 4 weeks. Changes in MVC-isometric, MVC-concentric, MVC-eccentric torque of the elbow flexors, and muscle thickness of biceps brachii and brachialis (MT) before and after the 4-week training were compared between 2DW and 3DW groups, and also compared to the 5DW group in the previous study. The 2DW group showed no significant changes in MVC torque. Significant (P < 0.05) increases in MVC-concentric (2.5 ± 10.4%) and MVC-eccentric (3.9 ± 4.9%) torque were observed for the 3DW group, but the magnitude of the increase was smaller (P < 0.05) than that presented by the 5DW group (12.8 ± 9.6%, 12.2 ± 7.8%). No significant changes in MT were evident for any of the groups. These results suggest that at least three days a week are necessary for the one 3-s maximal eccentric contraction to be effective for increasing muscle strength, and more frequent sessions in a week (e.g., 5 days) appear to induce greater increases in muscle strength.

Hybrid wind-PV farm with STATCOM for damping & control of overall chaotic oscillations in two-area power system using hybrid technique

This manuscript proposes a hybrid wind-photovoltaic farm with static synchronous compensator(STATCOM) for damping and controlling general chaotic-oscillations in a two-area power system. The proposed hybrid method is the joint operation of Tasmanian Devil Optimization(TDO) and Aquila Optimizer (AO) and together called as TDO-AO technique. The major objective of the proposed technique is minimizing the error, optimizes the performance of the system and regulates the controller parameters of proportional-integral (PI). The STATCOM is used to regulate the voltage and improve the power-factor of the system, leading to better power quality and reduced losses. The TDO is used to optimize the location and size of the wind-PV farm. The AO is utilized to enhance the parameters of STATCOM. The hybrid wind-PV farm with STATCOM can provide a renewable source of energy and improve the stability and reliability of the power grid. While being optimally compensated, the system is vulnerable to 3-phase faults. Zero damping is one more disturbance, along with a change in reference voltage and electric torque. The disturbances are created to simulate the worst scenarios, so that the hybrid wind-PV farm may be rigorously evaluated for its effectiveness in reducing the total chaotic oscillations. In Wind-PV-STATCOM, the gate signal is managed by a controller that separately controls the AC and DC currents. Then, the performance of proposed method is implemented in MATLAB and it is contrasted with the existing methods. From the simulation analysis, the proposed method based settling time is 1.00 sec that is less than the existing one.

Electrohydraulic Power Switching Control for Mechatronics–Electrohydraulic Power Coupling Electric Vehicles Considering Optimal Speed Thresholds

Switching between different working modes customarily brings sudden changes in torque and speed, leading to energy wastage for mechatronics‐electro‐hydraulic power coupling electric vehicles. Investigating the effect of vehicle speed thresholds on operating mode switching when working in concert with compound energy sources is timely. Thus, under the constraint of a known reference path, the optimal threshold is determined by weighing the path tracking accuracy and economic performance with the vehicle speed and the accumulator pressure as control variables. Wherein the constraint relationship between the factors is fully elucidated by combining various typical and actual road conditions. The validation results indicate a positive correlation between the starting acceleration capacity and the threshold value for a certain accumulator volume. The optimal speed thresholds under new European driving cycle, China light‐duty vehicle test cycle‐passenger, and actual routes are 4.1, 3.81, and 3.66 m s−1, with state of charge consumption rates of 6.30%, 8.56%, and 4.25%, respectively. More frequent speed switching may lead to excessive hydraulic power wastage, thereby increasing dependence on electrical power. Appropriate threshold setting can effectively enhance path tracking accuracy and hydraulic utilization under unpredictable road conditions. This research may in the future provide theoretical support for the rational control and interconstraint mechanism of energy utilization in hybrid vehicles.