Slip Control Research Articles

Applications and analyses of ammonia slip control based on precise ammonia injection technologies guided by big data

Abstract After the implementation of ultra-low emission policies, the pollutant emissions from the coal-fired power generation systems in China have been further reduced, which creates more critical requirements for the control accuracies of denitrification systems using selective catalytic reduction technology and controls of ammonia slip. This article presents big data-based technologies for controlling ammonia slip, through precise ammonia injections, which were applied and demonstrated for a flue gas denitrification system of a Chinese coal-fired power plant. Through examinations and analyses of the basic operating conditions of the unit and parameters, such as NOx emission control efficiency, ammonia injection amount of the denitrification system, and non-uniformity of NOx concentrations in the denitrification zone were compared before and after the implementation of these technologies, the outcome proves that this artificial intelligence algorithm based on big data can effectively solve the automatic control problem of denitrification system under complex working conditions such as varied unit loads, day and night operation changed coal source. In addition to the effective controls of the ammonia slip of the system, the controls of NOx emission of the system become more stabilized, creating a successful example for wider applications of these precise ammonia injection control technologies in the future. Analyses show that NOx non-uniformities can be reduced by more than 50% under both stable and variable load conditions. NOx fluctuations at the unit outlet are tightly controlled within ±10 mg/Nm3 under variable load conditions and within ±5 mg/Nm3 under stable conditions. The average ammonia injection amounts under various load conditions have decreased by 15.7%.

Alternative Fuels in Sustainable Logistics—Applications, Challenges, and Solutions

Logistics is becoming more cost competitive while customers and regulatory bodies pressure businesses to disclose their carbon footprints, creating interest in alternative fuels as a decarbonization strategy. This paper provides a thematic review of the role of alternative fuels in sustainable air, land, and sea logistics, their challenges, and potential mitigations. Through an extensive literature survey, we determined that biofuels, synthetic kerosene, natural gas, ammonia, alcohols, hydrogen, and electricity are the primary alternative fuels of interest in terms of environmental sustainability and techno-economic feasibility. In air logistics, synthetic kerosene from hydrogenated esters and fatty acids is the most promising route due to its high technical maturity, although it is limited by biomass sourcing. Electrical vehicles are favorable in road logistics due to cheaper green power and efficient vehicle designs, although they are constrained by recharging infrastructure deployment. In sea logistics, liquified natural gas is advantageous owing to its supply chain maturity, but it is limited by methane slip control and storage requirements. Overall, our examination indicates that alternative fuels will play a pivotal role in the logistics networks of the future.

Wheel Slip Equilibrium Point Model Reference Adaptive Control Based PID Controller for Antilock Braking System: A New Approach

This paper presents a new approach to wheel slip control in Antilock Braking System (ABS) using an Approximated First Order Wheel Slip (AFOWS) Model Reference Adaptive Control (MRAC) based PID (AFOWS-MRAC-PID) controller. An ABS was modeled in a MATLAB/Simulink environment using a quarter car model with the proposed controller. Simulations were conducted with a wide range of adaptation gains (50, 100, 150, 200, and 250) to study the effectiveness of the proposed control system. The results revealed that the proposed system could track and maintain 10% wheel slip and eliminate oscillation (instability) in terms of overshoot associated with conventional PID controllers, particularly on wet and snowy road surfaces, using adaptation gains of 150, 200, and 250. Overall, the proposed system provided the best performance in terms of stopping distance, vehicle braking velocity, and braking torque on all road surfaces with an adaptation gain of 250, although braking on dry road surfaces was the most effective.

Coordination control strategy of motion stability and tire slip for electric vehicle driven by in-wheel-motors

The Direct Yaw Moment Control (DYC) is a widely utilized technique for electric vehicles equipped with In-Wheel Motors (IWMs) to ensure yaw stability. However, most existing DYC studies calculate the additional control yaw moment solely based on the torque differences among the four IWMs, disregarding the nonlinear tire characteristics and wheel rotational movements. When road conditions are poor or torque changes are intense, the tire may slip, preventing it from generating the required longitudinal tire force for the desired direct yaw moment. To address this challenge, this study introduces a coordination control strategy for motion stability and tire slip in electric vehicles (EV) driven by IWMs. To enhance control performance, the nonlinear tire characteristics and wheel rotational movements are integrated into the modeling process when calculating tire forces. Additionally, a state and parameter coupling estimation algorithm is utilized to obtain feedback on tire parameters and vehicle motion states. Using these estimation results as a foundation, a coordination strategy is developed to achieve reference motion state tracking and tire slip ratio control. The Model Predictive Control (MPC) algorithm is employed to solve the control problem with constraints on both control inputs and outputs, and the estimation results are utilized to update the control model as well as provide states feedback. Simulations and experiments are conducted to validate the feasibility and effectiveness of the proposed control strategy. The results demonstrate that our proposed control strategy effectively improves vehicle stability by coordinating vehicle motion and tire slip control.

Fast In-Hand Slip Control on Unfeatured Objects With Programmable Tactile Sensing

Fast In-Hand Slip Control on Unfeatured Objects With Programmable Tactile Sensing

Effect of Weight Distribution and Active Safety Systems on Electric Vehicle Performance.

This paper describes control methods to improve electric vehicle performance in terms of handling, stability and cornering by adjusting the weight distribution and implementing control systems (e.g., wheel slip control, and yaw rate control). The vehicle is first simulated using the bicycle model to capture the dynamics. Then, a study on the effect of weight distribution on the driving behavior is conducted. The study is performed for three different weight configurations. Moreover, a yaw rate controller and a wheel slip controller are designed and implemented to improve the vehicle's performance for cornering and longitudinal motion under the different loading conditions. The simulation through the bicycle model is compared to the experiments conducted on a rear-wheel driven radio-controlled (RC) electric vehicle. The paper shows how the wheel slip controller contributes to the stabilization of the vehicle, how the yaw rate controller reduces understeering, and how the location of the center of gravity (CoG) affects steering behavior. Lastly, an analysis of the combination of control systems for each weight transfer is conducted to determine the configuration with the highest performance regarding acceleration time, braking distance, and steering behavior.

An Investigation in the Control Effectiveness of the Driving Wheel Slip Prevention System of a Diesel Engine Dump Truck

<div>This article proposes the structure and algorithm to design a PID controller for the driving wheel slip prevention system (DWSPs) of a dump truck using a diesel engine, which is equipped just only with a traditional high-pressure pump (HPP) under low-adhesion coefficient conditions. First, a longitudinal dynamic model, and a dynamic model of the wheel and powertrain of a dump truck are, respectively, established, and an experiment in the torque determination of a diesel engine is set up to investigate longitudinal vehicle dynamics as well. Then, a control system structure of the DWSPs for a dump truck using a diesel engine with a high-pressure inline fuel pump is proposed. Finally, based on performance analysis of other types of controllers, a PID controller is selected to control actual load level of a diesel engine. The criteria representing the vehicle’s acceleration such as the vehicle speed, vehicle acceleration, total slip time, and time to reach vehicle speed are selected to examine the effectiveness of the proposed controller when vehicles are being operated under the road surface conditions with low values of adhesion coefficient. The obtained results show that the proposed controller has greatly limited the driving wheel slipping phenomenon and increased the acceleration of the original dump truck. In addition, these findings can be used as a theoretical basis for the improvement of the wheel slip controllers in trucks using diesel engines.</div>

Synergistic enhancement of strength-ductility balance of TZM alloy through c-ZrO2 combined with large deformation and annealing

In this work, new TZM alloys containing 0.5 wt% and 1.0 wt% ZrO2 were prepared by powder metallurgy method, and their annealed microstructures and mechanical properties were studied. The TZM alloy sheet with 94 % deformation was recrystallized at 1200°C, and the elongation was greatly increased, and its UTS, YS and EL were 573 ± 10 MPa, 431 ± 7 MPa and 44 ± 0.2 %, respectively. After adding 0.5 wt% c-ZrO2, the best strength-ductility balance was achieved, and its UTS, YS, EL and PSE are 621 ± 3 MPa, 527 ± 4 MPa, 41.3 ± 0.58 % and 25.6 GPa·%, respectively, which was much larger than the PSE combinations of most Mo and TZM alloys. Microstructure analysis shows that the excellent synergistic effect arises from the low O impurity content and the control of dislocation density and dislocation slip by c-ZrO2 and the annealing process. Within the alloy, Ti and Zr react with O to produce TiO2 and ZrTiO4, which reduces the content of O impurities. Annealing provides sufficient space for dislocation slip, which coordinates the rotation of grain orientation during the stretching process. Coupled with the low O impurity concentration, results in excellent ductility of TZM alloys. Additionally, c-ZrO2 can effectively fix dislocations within the grains and interact strongly with dislocations, consequently enhancing the strength of the TZM alloy.

Cascade control algorithm for slip rate in a brake-by-wire system based on direct drive valve

To achieve a rapid response and precise control of braking hydraulic pressure, a brake-by-wire electro-hydraulic braking system based on a direct drive valve was designed. This system employs an electromagnetic linear actuator to drive the valve core directly, achieving swift adjustment of brake wheel cylinder hydraulic pressure. Given the strong coupling and non-linearity of the electromagnetic linear actuator, solely using a single-loop controller to control the slip rate can easily lead to weakened system performance. Hence, we proposed a cascade control algorithm for the brake-by-wire system, with an outer loop for slip rate control and an inner loop for direct drive valve position. The outer loop adopted a fuzzy PID control, while the inner loop adopted a model-free adaptive sliding mode control. By combining model-free adaptive control with a novel discrete exponential approach, we addressed the system’s non-linearity and unknown disturbances. A braking system test platform was constructed to verify the superior hydraulic tracking performance of this brake-by-wire system and to perform slip rate control performance analysis under different road conditions. Results demonstrated that compared to the fuzzy PID-MFAC algorithm, the proposed fuzzy PID-MFASMC control enhanced car slip rate control precision, and reduced both braking time and distance.

Stability control of single-wheel failure in four-wheel independent drive electric vehicles

The integration of the motor and transmission mechanism into the wheels of a four-wheel independent drive electric vehicle with hub motors increases the frequency of failures, especially torque output failures, which seriously affect vehicle stability and jeopardize driving safety. This paper focuses on the perspective of single-wheel torque output failure and studies the vehicle stability control strategy. Firstly, based on the constructed simulation dynamics model, a slip controller is designed to obtain the direct lateral moment. Then, based on the control allocation principle, upper-level lateral moment allocation rules are designed, and torque allocation rules under single-wheel torque output failure are formulated. Finally, simulation experiments are conducted under different operating conditions. The simulation results show that this control strategy can effectively control vehicle stability under single-wheel failure conditions and ensure safe driving.

Wheel slip ratio control considering time delay characteristic for electro-mechanical braking system

Electro-mechanical braking (EMB) system is a novel brake-by-wire (BBW) system which is the development direction of the electrification and intelligent vehicle braking system. However, as the EMB contains a mechanical transmission mechanism, there is an inevitable time delay in the braking process, which will cause problems of the wheel slip ratio control. To address this issue, this paper proposes a novel wheel slip ratio control system based on a hierarchical control framework, comprising a slip ratio control layer and a clamping force control layer. Firstly, an EMB actuator model considering the stiffness and damping characteristics of the ball screw is constructed and the correspondence between the model and the EMB object is verified. Subsequently, a model-based compensate active disturbance rejection control (MCADRC) algorithm based on the EMB actuator model is designed to compensate the uncertainty of the EMB and improve the tracking accuracy of the clamping force. Furthermore, the influence of time delay on slip ratio control is analyzed and a slip ratio controller considering time delay characteristic is developed to improve the slip ratio control quality. Finally, the HiL test results show that the proposed controller can effectively reduce the jitter of slip ratio by 1.2% and improve the response speed of slip ratio control 7.8%, which prove the real-time and effectiveness of the controller.

Engineering a PtCu Alloy to Improve N2 Selectivity of NH3-SCO over the Pt/SSZ-13 Catalyst.

Improving the N2 selectivity is always a great challenge for the selective catalytic oxidation of ammonia (NH3-SCO) over noble-metal-based (especially Pt) catalysts. In this work, Cu as an efficient promoter was introduced into the Pt/SSZ-13 catalyst to significantly improve the N2 selectivity of the NH3-SCO reaction. A PtCu alloy was formed in the PtCu/SSZ-13 catalyst, as confirmed by X-ray diffraction, transmission electron microscopy, energy dispersive spectrometry mapping, and X-ray absorption spectroscopy results. As indicated by the X-ray photoelectron spectroscopy analysis, the Pt species in the alloyed PtCu nanoparticle was mainly present in the electron-rich state on PtCu/SSZ-13, while the electron-deficient Cu and isolated Cu2+ species were both present on the surface of PtCu/SSZ-13. Due to such a unique alloyed structure with an altered oxidation state, the N2 selectivity of NH3-SCO on the PtCu/SSZ-13 catalyst was remarkably improved, while the NH3-SCO activity was kept comparable to that on Pt/SSZ-13. The reaction path was changed from the NH mechanism on Pt/SSZ-13 to both NH and internal selective catalytic reduction mechanisms on the PtCu/SSZ-13 catalyst, which was considered the main reason for the enhanced N2 selectivity. This work provides a new route to synthesize efficient alloy catalysts for optimizing the N2 selectivity of NH3-SCO for NH3 slip control in diesel exhaust purification.

Rule-based torque vectoring distribution strategy combined with slip ratio control to improve the handling stability of distributed drive electric vehicles

This study presents a hierarchical control system of handling stability for distributed drive electric vehicles. The desired direct yaw moment (DYM), determined by the upper-level controller, regulates the sideslip angle and yaw rate according to the robust H∞ control strategy. Meanwhile, the lower-level controller proposed in this research consists of a rule-based torque vectoring distribution and wheel slip ratio control. The proposed rule-based torque vectoring distribution strategy (TVDS) permits drive pattern switching based on the wheel slip ratio and preferentially employs the balanced torque vectoring distribution strategy to achieve DYM, wherein the distributed braking torque is achieved by motor regenerative braking. Here, the wheel with serious slipping was managed in a four-wheel drive pattern by the slip ratio controller. Then, the distribution strategies used for differential braking and proposed rule-based torque vectoring with and without slip ratio control were compared and analyzed in vehicle states and actuator outputs, respectively, by setting CarSim/MATLAB cosimulation under two driving conditions. Results demonstrate that the proposed rule-based TVDS can improve handling stability, energy efficiency, and riding comfort. Wheel locking can be successfully avoided by actuating the wheel slip ratio control, subsequently reducing the road adhesion requirements and improving vehicle handling stability and trajectory tracking accuracy.

Data Analysis and Traction Performance Evaluation of an Electric All-Wheel Drive Tractor During Agricultural Operation

Highlights The study evaluated the feasibility of using a new type of platform, the electric AWD tractor, for agricultural operations. The data for key components of the electric AWD tractor during plowing were analyzed. The traction performance of the electric AWD tractor was evaluated via tractive efficiency and dynamic ratio. The electric AWD tractor was expected to replace conventional tractors in terms of traction performance. Abstract. Owing to the increasing need for research on electric all-wheel drive (AWD) systems, an investigation on the AWD systems applicable to tractors was conducted in this study. The experimental platform consisted of an electric power transmission system including four sets of electric motors, helical and planetary reducers, wheels, and an electrical system including chargers, batteries (LiFePO4), converters, and inverters. The drive control system of the electric AWD tractor was divided into the AWD and the motor controller. The data measurement system consisted of analog (current and traction force) and digital (battery voltage, current, motor rotational speed, state of charge (SOC) level, and travel speed) components that communicate using a controller area network (CAN) bus. Data measured during plowing were used to calculate motor power, motor torque, traction power, and driving power to analyze the power consumption of an electric AWD tractor. The traction performance of the electric AWD tractor was evaluated using tractive efficiency, calculated values (traction power and driving power), and dynamic ratio. The maximum and minimum average voltage of the electric AWD tractor during plowing were 72.2 and 64.7 V, respectively, and the average value was measured as 68.2 V. The average value of the maximum current applied to the inverter was 362.4 A, and the mean value was measured as 187.5 A. The average value of the maximum rotational speed of the four motors was 2111.5 rpm, while the mean rotational speed during the operation was 1131.9 rpm. The average value of motor torque was 79.4 Nm. The decrease rate of battery SOC level per minute was calculated as an average of 1.4%/min. The maximum values of the traction and driving power during plowing were 42.0 and 73.7 kW. The maximum tractive efficiency (TE) was 0.77, with an average TE of 0.47. The maximum dynamic ratio (DR) was 0.28, with an average DR of 0.18. The TE of a conventional tractor was found to be a maximum of 0.61, with averages of 0.41, respectively. The average TE of the electric AWD tractor was approximately 14% higher than that of the conventional tractor. Data analysis indicates that the electric AWD tractor performing speed control is vulnerable to slip, and further research is necessary to improve AWD system performance through speed and slip control. Keywords: Data analysis, Data measurement system, Electric AWD tractor, Plowing, Traction performance.

Slip ratio control based on adaptive fuzzy sliding mode for vehicle with an electromechanical brake system

The development of vehicle intelligence has driven the evolution of brake-by-wire systems, with electromechanical braking (EMB) emerging as a crucial development in intelligent vehicle braking. To enhance the braking safety of EMB-equipped vehicles, this paper proposes a slip ratio control method based on adaptive fuzzy sliding mode control (AFSMC) to more effectively achieve wheel slip ratio tracking during braking. The approach involves establishing the mathematical model of the planetary gear-type EMB system and the vehicle’s longitudinal dynamics model. Additionally, a hierarchical collaborative control strategy is introduced, where the bottom layer employs the EMB clamping force control algorithm based on cascaded proportional-integral (PI), and the top layer integrates AFSMC to regulate the slip ratio. The simulation results, validated using the joint simulation platform of Simulink and Carsim under various conditions, illustrate that the AFSMC, compared to the conventional sliding mode controller (SMC), attains more precise control of wheel slip ratio while mitigating the chattering phenomenon. These findings suggest the potential of AFSMC for practical engineering applications.

Sliding Mode Wheel Slip Control for Regenerative Braking of an All-Wheel-Drive Electric Vehicle

Abstract Regenerative braking is one of the main advantages of electric propulsion systems. In such systems, the vehicle brake controller has to prioritize safety while maximizing the recovered energy at all times. This paper proposes a two-step hierarchical brake controller for a dual-motor all-wheel-drive electric vehicle. In the first step, a novel sliding mode controller (SMC) generates the total braking torque on each axle to independently control the slip on the front and rear wheels. In the second step, the torque split controller assigns motor and friction brake torques to maximize the recovered energy. By incorporating the effects of changing vehicle speed, the proposed SMC controller accounts for the nonlinearities in vehicle dynamics and tire model and considers the weight transfer due to vehicle deceleration while being robust to disturbances. Using simulations, we show that while the traditional SMC formulation is not effective during emergency braking scenarios, the proposed formulation successfully generates control commands to bring the vehicle to a stop position at a minimum distance. Furthermore, our controller can maintain both wheels in the stable slip region, even when starting from a locked position. The performance of the proposed controller is evaluated for an emergency braking scenario and on an aggressive segment of the US06 cycle.

Tire Performance and Testing under Longitudinal and Combined Slip States: Induced vs Resultant Wheel-Related Slip

ABSTRACT Tires influence many overall vehicle characteristics, including safety, performance, comfort, and handling. Testing is needed to characterize tires for the selection of original equipment manufacturers submissions as well as for the development of other suspension and chassis components. The reality that tire responses are highly nonlinear and change significantly with temperature, wear, and surface pairing makes testing to adequately characterize tires for vehicle development difficult. Furthermore, achieving robust, repeatable braking and driving measurements is particularly challenging. Unlike cornering tests, the test rig input is directly opposed to the tire response vector. Moreover, using an estimated parameter (e.g., slip ratio) as a control value prohibits a clear distinction between the linear test rig input and the nonlinear tire response. In this paper, the influence of the wheel-related slip control on tire performance under longitudinal and combined slip conditions is investigated. Two different tire types are measured in a laboratory environment on an MTS Flat-Trac CT+ tire test rig. A variety of test procedures are used to consider the influence of slip and torque rates under different operating conditions (e.g., wheel loads). A recommendation is given for a low-wear and cost-efficient testing methodology for an improved assessment of tire longitudinal and combined slip characteristics by using a linear test rig input.

Anti-lock braking control using an interval type-2 fuzzy neural network scheme for electric vehicles

Control precision and robustness can be regarded as essential challenges of slip ratio control because of the external uncertainties of road conditions and the internal delay response of braking actuators. In addition, it is difficult to obtain a trade-off between braking energy recovery efficiency and braking safety under some extreme braking conditions. To synchronously improve both slip ratio control and braking energy recovery efficiency for different road conditions, an anti-lock braking system (ABS) using a novel interval type-2 fuzzy neural network (IT2FNN) control scheme is proposed for electrohydraulic braking systems. The novel IT2FNN control scheme with five layers is designed to calculate the commanded braking torque. The membership function layer utilizes type-2 fuzzy sets to describe the slip ratio error degree, which enhances the scheme’s anti-interference ability, and the enhanced Karnik-Mendel (EKM) algorithm is used in the type-reduction layer to accelerate computation. Additionally, the network adjusts the parameters of the membership function and rules by decreasing the performance function value corresponding to the braking torque error to improve slip ratio control and enhance the self-adaptation capacity. Simulations showed that IT2FNN control can not only improve slip ratio control performance and decrease the braking torque error but also enhance the energy recovery efficiency of regenerative braking on different road surfaces.

Development of the simulation model for testing the axial torque distribution in an electric vehicle with the dual-motor layout

BACKGROUND: The market of vehicles using electricity as an energy source demonstrates significant growth. Currently, there are more than twenty million electric vehicles worldwide. Leading manufacturers give the high priority to development of electric transport due to lower vehicle service costs, ease of driving as well as zero emissions in environment and almost complete noiselessness at motion. In addition, using the full-wheel drive in an electric vehicle makes it possible to improve off-road capability, ensures more balanced chassis control, precise following the path and constant accuracy of steering. AIMS: Ensuring increase in vehicle course stability, delivering the maximal torque regarding vehicle motion conditions and slip control in dual-motor layouts of electric vehicles. METHODS: In order to solve the given task, implementation of the special-purpose algorithm of torque distribution between driving axles of an electric vehicle is assumed. The paper presents the development of the simulation model of a vehicle, built in the Simcenter Amesim software and considering dynamic properties and features of the vehicle. This model was implemented into the Labcar hardware-in-the-loop facility. RESULTS: The simulation result is comparison with the data obtained during ground testing of the prototype and confirming the aim of simulation model development, in particular the capability of revision and preliminary setting up the algorithm of torque distribution between driving axles of a vehicle. CONCLUSIONS: Based on the results of the testing of the developed facility, it can be concluded that the developed simulation facility is suitable for solving the simulation tasks including research, debugging and primary calibrations of the algorithm of torque distribution between driving axles of a full-wheel driven electric vehicle. The errors at simulation of operation modes relevant to longitudinal and lateral dynamics of the prototype is no more than 7.5% that complies with the simulation aims.

Research on Terrain Mobility of UGV with Hydrostatic Wheel Drive and Slip Control Systems

The article explored the potential for enhancing the off-road mobility of unmanned ground vehicles (UGV) equipped with a hydrostatic drive system. The analysis showed that effectively overcoming rough or soft terrain demands a slip limitation. In the UGVs with hydrostatic drives, flow dividers are used for this purpose. Unfortunately, they have certain drawbacks, such as reduced efficiency due to pressure losses. In order to minimize this phenomenon, an external braking system was used as a new slip control system. Therefore, simulation studies were carried out to assess the new slip control system while overcoming terrain obstacles due to the reduction of energy consumption and improving the mobility of the UGV.