Effect of suspension training on neuromuscular function, postural control, and knee kinematics in anterior cruciate ligament reconstruction patients

BACKGROUND Suspension training(SET)is a method of neuromuscular training that enables the body to carry out active training under unstable support through a suspension therapy system.However,there have been few reports in the literature on the application of SET to anterior cruciate ligament reconstruction(ACLR)patients.It is not clear what aspects of the patient's function are improved after SET.AIM To investigate the effect of SET on the neuromuscular function,postural control,and knee kinematics of patients after ACLR surgery.METHODS Forty participants were randomized to an SET group or a control group.The SET group subjects participated in a SET protocol over 6 wk.The control group subjects participated in a traditional training protocol over 6 wk.Isokinetic muscle strength of the quadriceps and hamstrings,static and dynamic posture stability test,and relative translation of the injured knee were assessed before and after training.RESULTS The relative peak torque of the quadriceps and hamstrings in both groups increased significantly(P<0.001),and the SET group increased by a higher percentage than those in the control group(quadriceps:P=0.004;hamstrings:P=0.011).After training,both groups showed significant improvements in static and dynamic posture stability(P<0.01),and the SET group had a greater change than the control group(P<0.05).No significant improvement on the relative translation of the injured knee was observed after training in either group(P>0.05).CONCLUSION Our findings show that SET promotes great responses in quadriceps and hamstring muscle strength and balance function in ACLR patients.

Deep learning-based fault diagnostic network of high-speed train secondary suspension systems for immunity to track irregularities and wheel wear

Fault detection and isolation of high-speed train suspension systems is of critical importance to guarantee train running safety. Firstly, the existing methods concerning fault detection or isolation of train suspension systems are briefly reviewed and divided into two categories, i.e., model-based and data-driven approaches. The advantages and disadvantages of these two categories of approaches are briefly summarized. Secondly, a 1D convolution network-based fault diagnostic method for highspeed train suspension systems is designed. To improve the robustness of the method, a Gaussian white noise strategy(GWN-strategy) for immunity to track irregularities and an edge sample training strategy(EST-strategy) for immunity to wheel wear are proposed. The whole network is called GWN-EST-1 DCNN method. Thirdly, to show the performance of this method, a multibody dynamics simulation model of a high-speed train is built to generate the lateral acceleration of a bogie frame corresponding to different track irregularities, wheel profiles, and secondary suspension faults. The simulated signals are then inputted into the diagnostic network, and the results show the correctness and superiority of the GWN-EST-1DCNN method. Finally,the 1DCNN method is further validated using tracking data of a CRH3 train running on a high-speed railway line.

Refined disturbance observer based prescribed performance fixed-time control of high-speed EMS trains with track irregularities

High-speed Electromagnetic Suspension(EMS)train is continuously impacted by the irregularity of the track,which worsens the levitation performance of the train.In this paper,a composite control scheme for the EMS is proposed to suppress track irregularities by integrating a Refined Disturbance Observer(RDO)and a Prescribed Performance Fixed-Time Controller(PPFTC).The RDO is designed to estimate precisely the track irregularities and lumped disturbances with uncertainties and exogenous disturbances in the suspension system,and reduce input chattering by applying to the disturbance compensation channel.PPFTC is designed to converge the suspension air gap error to equilibrium point with prescribed performance by completing error conversion,and solve the fast dynamic issue of EMS.And the boundary of overshoot and steady-state is limited in the ranged prescribed.A theoretical analysis is conducted on the stability of the proposed control method.Finally,the effectiveness and reasonability of the proposed composite anti-disturbance control scheme is verified by simulation results.

Comprehensive Model Construction and Simulation for Superconducting Electrodynamic Suspension Train

With the advantages of levitation/guidance self-stability,large levitation gap,and high lift-to-drag ratios,superconducting electrodynamic suspension(SC-EDS)train is becoming a viable candidate for the high-speed and ultra-high-speed rail transportation.In order to provide the basis for designing the optimization and control strategy,this paper establishes a comprehensive model for the SC-EDS train,which considers the dynamics of the bogie and car body in all directions.The obtained model reveals the complex coupling and feedback relationships among the variables,which cannot be described by the existing local models of the SC-EDS train.Simulation examples under different parameters and initial conditions are presented and discussed to demonstrate the potential use of the model given in this paper.