As CT Research Articles

Centralized and distributed coupling traction control of electric vehicles on split ramps

The pass ability on split ramps is an important dynamics performance of electric vehicles (EVs). However, the current traction control system (TCS) requires the vehicle to have a high-intensity driving capability and sometime the braking assistance control is required, which is a waste of cost and energy. To improve the traction control ability and reduce the power demands, a centralized and distributed coupling TCS based on the designed dual-mode coupling drive system is proposed. The coupling traction control mechanism is analyzed, the TCS based on S-line control and optimal slope-seeking algorithm is designed, and the traction control effect is verified by the co-simulation and real vehicle road test. The research results show that adopting coupling traction control can give full play to system power to improve the pass ability, the optimal slip rate control can be realized and the control difficulty also be reduced. It laid a theoretical basis for the pass ability improvement of EVs on split ramps and the new application of dual-mode coupling drive system.

Co-Simulation-Based Verification of Torsional Vibration Protection of Electric-Driven Railway Vehicle Wheelsets

Torsional vibration is an oscillation phenomenon occurring at driven railway vehicle wheelsets. As the resulting dynamic stresses can be significantly larger than the maximum static motor torque, axle and press fit are at risk of failure. To prevent dangerous vibration events and with these, press fit and axle from failure, traction drive manufactures nowadays used to implement vibration suppression algorithms in drive controls. In this paper, the effectiveness of such suppression algorithms is analyzed. Furthermore, as a pilot survey, we analyze to what extend traction controls influence the excitation of torsional vibration.

Application of independent‐left‐and‐right‐wheel‐driving force controller to torque vectoring differential with two‐input‐two‐output motor drive system for electrified vehicles

AbstractA torque‐difference‐amplification torque vectoring differential (TDA‐TVD), which is composed of a two‐input‐two‐output system, has a great potential for cornering maneuverability; however, the overall controllability of slip ratio or driving force control is difficult owing to its complex mechanical structure. In order to enhance the controllability of TDA‐TVD, this study proposes a design method to apply a driving force controller (DFC) with a decent slip ratio and driving force controllability, which was originally intended for independent wheel drive systems. An experimental verification on a slippery road using a real vehicle with the TDA‐TVD indicated that the DFC can be applied to the TDA‐TVD and that it improves the overall performance of the traction control.

Traction Adaptive Motion Planning and Control at the Limits of Handling

In this article, we address the problem of motion planning and control at the limits of handling, under locally varying traction conditions. We propose a novel solution method where traction variations over the prediction horizon are represented by time-varying tire force constraints, derived from a predictive friction estimate. A constrained finite time optimal control problem (CFTOC) is solved in a receding horizon fashion, imposing these time-varying constraints. Furthermore, our method features an integrated sampling augmentation procedure that addresses the problems of infeasibility and sensitivity to local minima that arise at abrupt constraint alterations, for example, due to sudden friction changes. We validate the proposed algorithm on a Volvo FH16 heavy-duty vehicle, in a range of critical scenarios. Experimental results indicate that traction adaptive motion planning and control improves the vehicle’s capacity to avoid accidents, both when adapting to low local traction, by ensuring dynamic feasibility of the planned motion, and when adapting to high local traction, by realizing high traction utilization.

Traction control of space tubular shaped mandrel and detection of preform braiding angle

The braiding quality of composite preforms has a significant influence on their mechanical properties. To address the difficulties in the design of the processing technology and the stability of the surface quality of the fabric during the braiding process of the spatial special-shaped mandrel, a robot control method was proposed for prefabrication. Regarding branding of the formed body and inspection of the braiding angle of the fabric by machine vision for quality control, in this study the spatial special-shaped mandrel was discretized, the position and attitude of the tool center point were calculated, and the robot pulling speed was calculated. The calculation was performed to realize the automatic compensation of the braiding angle and, finally, the braiding angle of the fabric surface was detected by machine vision. The experimental results showed that the control method could effectively reduce the braiding angle error of the preform within ±2° through the detection of the visual inspection algorithm and could improve the quality of the preform and the detection speed of the braiding angle in actual production.

Active motor damping strategy for driveline vibrations of a hybrid electric vehicle during ABS operation

Torsional drivetrain vibrations in hybrid and electric drivetrains, which occur during traction and braking control, are commonly encountered. This problem occurs mainly due to the weak damping characteristic of the hybrid/electric drivetrain and the fast time response characteristics of the electric motor. An active motor damping (AMD) control algorithm for a hybrid electric vehicle, considering ABS braking maneuvers on different road conditions, is developed in this work. The control problem is structured such that the control objective is disturbance rejection against the estimated brake torque signal received from the ABS module. Communication delay between the ABS and motor control module is handled within the control strategy. State feedback control strategy is used with the linearized version of the non-linear state-space equations together with an Extended Kalman filter. Gear backlash is taken into account without the need to estimate the mode of backlash. In the development of the controller, state feedback gains are set such that the ABS functionality on tire slip regulation is not altered. Existing studies in the literature feedback only the angle of twist and axle wrap angular speed for damping the vibrations. The structure of the controller in this study is different in that it estimates and feeds back tire slip, in addition to these two. Simulation results show the effectiveness of the controller in reducing the angle of twist without deteriorating ABS tire slip control and braking performance of the vehicle.

Acceleration slip regulation by electric motor torque of battery electric vehicle with nonlinear model predictive control approach

Step increase of electric motor torque results in wheel slip during the acceleration of battery electric vehicle (BEV), making vehicle body instability paramount. This is particularly challenging for regulating the torque of electric motor to keep stability in the process of acceleration, for which regulating the wheel slip to an ideal set-point is difficult for the central driving powertrain that adopts one electric motor to drive both left and right wheels by a differential. While much of the research on acceleration slip regulation has focused on solving the wheel anti-slip of internal combustion powertrain by electronic stability programme, comparatively little is known about the wheel slip control by electric motor torque of the central driving powertrain that is the most common style of driveline in the market of BEV currently. Here we discuss a series of studies on the acceleration slip regulation by electric motor torque that, collectively, design an approach of how the nonlinear model predictive controller based on a novel driving dynamics model regulates the wheel slip to an ideal set-point from the ideal slip ratio curve. Testing and validating this approach embedded into vehicle control unit are carried out in a BEV to fully realise the wheel slip control by electric motor torque during the acceleration.

ANALYSIS OF WAYS OF INCREASE OF TRACTION AND ENERGY PROPERTIES OF WHEELED ELECTRIC TRACTORS OF TRACTION CLASS 0,6

The article searches for and analyzes the design parameters of a wheeled electric tractor, which provide maximum efficiency and economy in the entire range of traction forces of the electric tractor in order to improve the traction and energy properties. Also, modern developments of new electric tractors in Ukraine were analyzed, bright examples are given, which are currently being developed and modernized. The choice of tractor layout is analyzed. Models of tractors with different axle speeds are analyzed, the possibilities of further calculation of electric tractors with the help of generalized mathematical models are considered, such as traction motor models, battery operation models, electric tractor control system models, traction torque determination and for comparison of ICE model and traction calculation

A Fuzzy-based Sliding Mode Control Approach for Acceleration Slip Regulation of Battery Electric Vehicle

Due to quick response and large quantity of electric motor torque, the traction wheels of battery electric vehicle are easy to slip during the initial phase of starting. In this paper, a sliding mode control approach of acceleration slip regulation is designed to prevent the slip of the traction wheels. The wheel slip ratio is used as the state variable for the formulation of system dynamics model. The fuzzy algorithm is utilized to adjust the switch function of sliding mode controller. After stability and robustness analysis, the sliding mode control law is transferred into C code and downloaded into vehicle control unit, which is validated under wet and dry road conditions. The experimental results with a small overshoot and a quick response during starting indicate that the sliding mode controller has good control effect on the slip ratio regulation. This article proposes an acceleration slip regulation method that improves the safety during acceleration for battery electric vehicle.

A tactics for treating large skin wounds on the head

An open wound on the head is an injury (skin tear) of all scalp external layers including dermis, subcutaneous fatty tissue, aponeurosis, muscles, vessels and nerves with intact skull bones and intact neurological reactions [1].Extensive wounds of the external head layers, in addition to a standard threat to the human health, bear an additional risk due to their close localization to the brain. Because of the abundant blood supply to scalp soft tissues, high rate of volumetric blood flow (50–60 milliliters per 100 g of brain tissue), numerous extra-, intracranial arterial and venous anastomoses, there is a real danger of spreading the infection inside the skull and developing meningitis or encephalitis.Problems of care of patients with extensive head wounds, risk of complications that can cause severe consequences determine the relevance of the issue presented in this work.Objective. To analyze treatment results of patients admitted to the emergency department of Mariinskaya State City Hospital in St. Petersburg within three months in 2021 and to develop an optimal tactics for treating patients with extensive wounds of the scalp.Material and research methods. 2245 patients with various types of head injury were admitted to the hospital; 610 (27.2 %) of them had damage of the external scalp layers. Each patient had standard clinical and laboratory examination and multislice computed tomography (MSCT) examination of the head at 64-slice Definition AS (Siemens, Germany) CT scanner. In the emergency department, all patients who were injured by high-energy traumatic objects had the primary surgical debridement; all patients who were injured by low-energy traumatic objects had wound toilet and wound suturing. Three most representative cases with extensive wounds of the external scalp (over 10 cm) with illustrations are presented in the article as clinical examples.Results. All patients had good outcomes. There were no any signs of wound infection either.Conclusion. A thorough primary surgical debridement of scalp wounds with their drainage followed by observation and treatment in the hospital is a necessary condition for successful healing of large scalp wounds.

P380 THE REEL‘S SYNDROME : A RARE COMPLICATION AFTER PACEMAKER IMPLANTATION

Abstract We report the case of a 83–year–old male who underwent single chamber pacemaker implantation in another center for bradyarrhythmia (atrial fibrillation) symptomatic for syncope. A ventricular lead was implanted in the apical septum, the post–procedural posterior–anterior chest radiograph showed correct placement of the leads and generator. Approximately 4 months after the implant, the patient came to our observation for repeated electric pulsations in his left shoulder. The patient was affected by mild dementia and was asymptomatic except for the presenting symptomatology, in particular he denied a history of syncope. The ECG showed arrhythmia due to atrial fibrillation, ventricular undersensing, and lack of ventricular capture (Figure 1). The chest X–ray showed the complete dislodgement of the ventricular lead tip apparently into the vein secondary to the rotation of the pulse generator on its transverse axis with consecutive coiling of the lead (Fig. 2). These findings were consistent with Reel syndrome The patient was admitted to undergo a lead repositioning attempt in consideration of the recent first implant. During the surgery, however, it was shown that the lead was completely displaced from the venous system, near the pectoral muscle. This extreme dislocation of the lead has been related to the electric pulsations felt by the patient. We proceeded with a new re–implantation of the lead and removal of the previous one. The lead was firmly tied to the pectoral muscle with 2 silk points with slight traction control of optimal fixation. Reel‘s syndrome is a variant of the better known Twiddler syndrome, characterized by the coiling of catheters along the transverse axis of the pacemaker. It is often a complication due to the manipulation of the generator by the patient, unlike Twiddler syndrome it occurs early and the leads remain intact. This syndrome is one of the most serious complications of pacemaker or defibrillator implants, it can be potentially fatal due to lack of therapy in the case of defibrillators, or asystole in pacemaker–dependent patients.

Acceleration‐based wheel slip control realized with decentralised electric drivetrain systems

Traction control is one of the most important functions in vehicle drivetrain systems. When a vehicle is driven on a low-friction road surface, loss of traction force can cause the driven wheels to spin. This reduces vehicle acceleration performance and can even cause the driver to lose control of the vehicle. The high bandwidth of electric machine control in electric vehicles gives more possibilities to regulate driving torque on wheels and prevent wheel spin. An acceleration-based wheel slip control is designed and investigated. Compared to traditional slip-based traction control, the proposed method does not depend on the estimation of the vehicle speed and only relies on the driven wheel rotational acceleration. The control method is verified using the simulation of an electric vehicle with a decentralised electric drivetrain system. The vehicle and the electric drive are modelled in CarMaker and PLECS, respectively. The simulation results show that the proposed method is able to prevent the driven wheel from spinning when the vehicle is accelerated on an ice road. In addition, the control is fast enough and requires only half a second to reduce the wheel acceleration to a normal range.

Rice row tracking control of crawler tractor based on the satellite and visual integrated navigation

To achieve autonomous navigation of the crawler tractor in the paddy field, a set of control system was developed by integrating the satellite and visual navigation. The system is mainly composed of a satellite module, a visual module and a controller. The satellite module detects the deviation information between the tractor’s position and the pre-set line AB using GPS Real–time Kinematic (RTK) technology and the navigation is achieved according to the preview point tracking algorithm. The visual module obtains the rice crop images in real time by camera, and the binary image segmentation is completed by ExG(2G-R-B), Otsu and mask method. Then the region search algorithm is used to classify the region of each rice row, and the visual navigation path is fitted by the weighted least square method, and the weight value is based on the lookahead distance. Finally, the preview point tracking algorithm is used to realize the visual navigation. Furthermore, the control division line between the satellite navigation and visual navigation is established, the threshold value of which is determined based on the crop row deviation due to the satellite navigation when rice crops were planted. The crawler tractor navigation tests were conducted to evaluate the performance of the integrated navigation system. When the speed of the tractor was 0.4∼0.6 m/s, 0.7∼0.9 m/s and 1.0∼1.2 m/s, the maximum lateral deviation of the tracking by visual navigation was 0.18 m, 0.15 m and 0.14 m, respectively, and the RMSE was 55 mm, 64 mm and 60 mm, respectively. Under the same speed, when the threshold value was set to 0.15 m, the maximum lateral offset of the tracking by integrated navigation was 0.14 m, 0.13 m and 0.12 m, respectively, and the RMSE was 41 mm, 50 mm and 55 mm, respectively. The experimental results indicate that the satellite navigation module in the integrated navigation system functions well in rice row tracking when some seedlings are missing, and significantly reduces the navigation deviation and the degree of deviation fluctuation.

An explicit modelling method of joint-space inertia matrix for tree-chain dynamic system

The joint-space inertia matrix (JSIM) plays an important role in the dynamic simulation and control of robot mechanisms. In this paper, a novel explicit modelling method of JSIM for tree-chain dynamic system is proposed. By this method, each element of the inertia matrix has an explicit expression with respect to input parameters. Thus, the modelling process only includes the process of coordinate system establishment and parameter determination without the intermediate process of complex analysis and derivation. Moreover, the matrix elements are decoupled, which is beneficial to further study of the properties of JSIM on the one hand. On the other hand, multiple matrix elements can be computed simultaneously to reduce the computation time. Compared with the existing explicit method, this method has higher modelling and computational efficiency. Finally, a planar manipulator with three degrees of freedom (DOFs) is used to verify the proposed method in serial-chain application and show its modelling convenience. A lunar rover example is used to verify the proposed method in tree-chain application, and the modelling results are applied to the traction control in the simulation software of lunar rover.

APPLICATION OF PID METHOD TO CONTROL TRACTION ON THE VEHICLES THROUGH CONTROLLING THE BRAKE MOMENT AT THE TWO DRIVING WHEELS

A vehicle differential is a device that divides engine power between the two driving wheels and allows the wheels to rotate at different speeds when the vehicle moves on the road. The speed difference depends mainly on the grip between the wheels and the road surface. When the traction acting on both driving wheels is equal,the differential will distribute traction equally, helping the vehicle move stably on a straight road. However, if one of the two driving wheels rolls on a slippery road, the differential will distribute more engine power to this wheel. As a result, the vehicle’s motion is unstable, engine power is lost, the vehicle cannot move. To solvethe problem, using a limited-slip differential, an active differential or a traction control system is considered an optimal solution. This study uses the brake moment acting on the skidding wheel to redistribute the engine power at the two driving wheels and uses the PID method for traction control at the drive wheels. Survey results show the effectiveness of the designed controller.

A novel flexible auxiliary single-arm transluminal endoscopic robot facilitates endoscopic submucosal dissection of gastric lesions (with video).

Using conventional endoscope to perform endoscopic submucosal dissection (ESD) is difficult because of the one-handed operation and blind dissection caused by gravity. Poor visualization of the submucosal plane causes ESD to be associated with a high risk of bleeding and perforation. This study aimed to develop a novel ESD-assistive robot system and to evaluate its efficacy. A novel flexible auxiliary single-arm transluminal endoscopic robot (FASTER) was developed. A total of 36 artificial lesions in ex vivo porcine stomachs were removed using the FASTER-assisted ESD method (n = 18) and the conventional ESD method (n = 18). Lesions were 2cm or 4cm in diameter, located on the anterior and posterior walls of the antrum. Primary outcome measurements were dissection time and dissection speed. The dissection time in FASTER-assisted ESD was significantly shorter than that in conventional ESD (7min vs 13min, p = 0.012), mainly because of the faster dissection speed (148.6 vs 97.0 mm2/min, p = 0.002). The total procedure time in FASTER-assisted ESD was shorter than that in conventional ESD, but the difference was not significant (16min vs 24min, p = 0.252). Complete en bloc resection was achieved in all lesions. No perforations were detected. The FASTER exhibited the ability of regrasp, multidirectional traction, and proper tension control during ESD. FASTER significantly increased the dissection speed by providing proper traction and achieving good submucosal vision. This new device is expected to facilitate ESD in clinical practice.

Longitudinal Dynamic Modeling and Driving Cycle Tracking Control of an Electric-Driven Vehicle by Means of MATLAB/Simulink/Simscape

MATLAB, Simulink, and Simscape are market-leading products in Model-Based Design (MBD). Applying acausal and causal modeling methods to model the physical plant and control algorithms of mechatronic systems results in high-fidelity virtual prototype models that can be used for Model-in-Loop (MiL) development. In this paper, an electric-driven vehicle is modeled, which can execute various driving cycle inputs. PID controllers are used in order to get the appropriate plant inputs. Idealized anti-lock braking system (ABS) and traction control system (TCS) algorithms provide robustness when the driving cycle input is near-infeasible. The control algorithm is validated in the cases of feasible and infeasible driving cycle inputs.

Slip Detection and Control for Harvesting Machines

This paper deals with a traction control system (TCS) for combine harvesters. Off-road vehicles typically have a lower traction efficiency compared to on-road vehicles. The rising demand for high-power agricultural machines leads to a significant need for higher traction efficiency to reduce power loss. A TCS can help to increase the traction efficiency by controlling the slip ratio. Further positive effects are the reduction of soil compaction and longitudinal stability of the vehicle. In this paper a combine harvester model is introduced to describe the dynamic interaction between drivetrain and vehicle longitudinal dynamics which include slip. This model depends on several parameters, which can be estimated online along with the determination of the maximal slip ratio. The plant model is successfully validated using field test measurements. A PID traction controller and a sliding-mode traction controller are designed and compared. Two control concepts are evaluated utilizing this model and these controllers. Simulation results show the effectiveness and efficiency of the proposed TCS.

Features of the practical implementation of energy-saving algorithms for control of the collector traction drive of the main line electric locomotives

Features of the practical implementation of energy-saving algorithms for control of the collector traction drive of the main line electric locomotives

Intraoperative halo-femoral traction during posterior spinal arthrodesis for adolescent idiopathic scoliosis curves between 70° and 100°: a randomized controlled trial.

Surgical management of scoliosis curves between 70° and 100° remains controversial. The authors designed this randomized controlled trial to validate the efficacy of intraoperative halo-femoral traction (IOHFT) in patients with adolescent idiopathic scoliosis (AIS), Cobb angles between 70° and 100°, and flexibility < 35%. The authors prospectively recruited and randomized 29 patients with severe AIS scheduled for posterior surgery into a traction group or control (nontraction) group. The primary outcome measures were operative time, blood loss, and length of hospital stay. Secondary outcomes included degree of spine deformity correction, traction-related complications, and health-related quality of life. In the traction group, the average preoperative Cobb angle was 83.2°, with an average 20.6% flexibility. The average postoperative Cobb angle was 16.1° and the major curve was 18.3° at the final follow-up. In the control group, the average preoperative major curve was 80.3° with 22.8% flexibility. The average postoperative Cobb angle was 16.1° and the major curve was 18.1° at the final follow-up. The operative duration was 325.7 minutes for the traction group and 385.4 minutes for the control group (p = 0.018). Compared with the control group, the traction group had a 29.5% reduction in intraoperative blood loss and a significantly lower rate of blood transfusion (13.3% vs 50.0%, p = 0.033). There were no neurological complications in either group. One patient in the traction group had a superficial infection at the traction site. Use of IOHFT contributed to significant reductions in operative time and blood transfusion requirements, with no added morbidity. It is an effective and safe method to assist correction of AIS curves between 70° and 100° and flexibility < 35%.