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Development of Torque Control Algorithm for 6x6 Skid Steering Vehicle
Mian Ashfaq Ali,Chang-Jun Kim,Dong-Hyung Kim,Young-Ryul Kim,Chang-Soo Han 한국자동차공학회 2009 한국자동차공학회 학술대회 및 전시회 Vol.2009 No.11
Skid steering vehicles have good maneuverability and mobility on rough and extreme terrains. In skid steering vehicle all the wheels are non-steerable and the vehicle is turned as a result of the application of differential torque to wheels on opposite sides. The use of electric motors in each wheel instead of mechanical drives is more advantageous regarding performance. The electric motor response time is very short and also the torque can be known from motor current. Moreover using In-Wheel-Motor each wheel can be control independently. In this study first we modeled the Six Wheel Skid Steering Vehicle having 6 in-wheel motors then we proposed Torque Control Algorithm. Two PID controllers with filters are used to achieve the desired velocity and desired yaw rate. This torque control algorithm determines the torque commands for each wheel based on the desired yaw rate and desired velocity. The slip ratio controller is applied to each wheel independently as minor loop to prevent slipping. This algorithm is applied to Driver-In-Loop mode using the developed 6x6 model and simulations are carried out using MATLAB Simulink®. These results show that this control algorithm can be use effectively in controlling the skid steering vehicle on different road conditions.
Ali Mian Ashfaq,Sang-Ho Kim,Chang-Jun Kim,Chang-Soo Han 한국자동차공학회 2013 한국자동차공학회 부문종합 학술대회 Vol.2013 No.5
Due to the environmental challenges and low emission regulations, research is going on Electric Vehicles (EV). The electric vehicle which is equipped with in-wheel motors also provides good control architecture. A variety of Electric Vehicle designs are being considered such as Rear Wheel Drive (RWD) EV, Front Wheel Drive (FWD) EV, Rear Wheel Drive with Steer-By-Wire System (SBW) and Four Wheel-Drive (4WD) with Steer-By-Wire (SBW) Systems. There is also another class of Electric Vehicle with Skid Steering /Differential Torque Driving Vehicle where differential torque is applied to the nonsteerable wheels for turning the vehicle. Adequate motion control algorithms that fulfill the driving control and safety criteria are being research for each kind of electric vehicle. However on the basis of different number of in-wheel motors each class of vehicle has its performance boundaries and limitations. In this paper we study the performance boundaries between the Four- Wheel-Drive with Steer-By-Wire Steering System and Rear-Wheel-Drive vehicle with Steer-By-Wire Steering System. All the simulations are carried out using TruckSim and results are reported in this paper.
Mian Ashfaq Ali,Chang-Jun Kim,Hyun-Soo Shin,Young-Ryul Kim,Chang-Soo Han 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
The skid steered vehicles are favored for military use in off road operations because of their high maneuverability and mobility on extreme terrains and obstacles There is a trend to transform from the skid steered tracked vehicle to the skid steered wheeled vehicle for having high speed at the expense of the reduced mobility.. All the wheels in this case are non-steerable. The skid steered vehicles are tum by generating different longitudinal forces by the tires due to the application of different torques to wheels on opposite sides of the vehicle. To analyze the behavior of skid steering in the simulated environment we need to have a good mathematical model. The mathematical modeling of skid steering is complex because of the skidding phenomenon which is difficult to model. In this study we modeled the Skid Steering Six Wheeled Vehicle (6×6) mathematically with actual parameters of a 6×6 Hybrid Electric Vehicle and then it is simulated for different maneuvers by using the torque control algorithm to check the behavior of the vehicle before carrying out the actual experiments on the vehicle. The Pacejka and Sharp tire model is used in this study which can predict the longitudinal and lateral tire forces at combined slip conditions during the motion. The motion is compared with Ackermann steered vehicle of the same dimensions and parameters. A torque control algorithm is simulated using the 6×6 model.
Mian Ashfaq Ali,김창준,김상호,Abdul Manan Khan,Junaid Iqbal,Mohammad Zuhaib Khalil,임동환,한창수 제어·로봇·시스템학회 2017 International Journal of Control, Automation, and Vol.15 No.2
This article proposes an automatic longitudinal deceleration based method for multi-wheel vehiclerollover safety in autonomous mode. The information of lateral acceleration and vehicle roll angle is used togenerate the longitudinal acceleration at which the vehicle will remain stable to rollover. The lateral and roll dynamicsare coupled with longitudinal dynamics using a potential field function for lateral acceleration. This virtualpotential field is developed on g-g diagram which represents vehicle portrait of lateral and longitudinal accelerationon abscissa and ordinate respectively. The motion of vehicle is represented by a point moving on this phase portraitof g-g diagram. TruckSim model of multi-wheel military vehicle with in-wheel motors is used with this algorithmwhich shows that the vehicle is less susceptible to rollover. The safe longitudinal acceleration is achieved by torquecontrol of in-wheel motors fitted in each wheel. Using this method, the vehicle followed the desired trajectory ashigher speeds which are safe. This is particularly useful for vehicle autonomous driving with rollover stability.
Motion Control of a 6WD/6WS Wheeled Platform with In-wheel Motors to Improve Its Maneuverability
한창수,김창준,Ali Mian Ashfaq,김상호,백성훈,김영수,황순웅,장재호 제어·로봇·시스템학회 2015 International Journal of Control, Automation, and Vol.13 No.2
This study researches the tracking control problem for discrete-time systems with multiple input delays affected by sinusoidal disturbances. This study is organized around the expression of sinusoidal and disturbances and the delay-free transformation. First, based on the periodic characteristic of the sinusoidal disturbance, the sinusoidal disturbances are considered as the output of an exosystem. By proposing a discrete variable transformation, the discrete-time system with multiple input delays and the quadratic performance index are transformed into equivalent delay-free ones. Then, by constructing an augmented system that comprises the states of the exosystems of sinusoidal disturbances, the reference input, and the delay-free transformation systems, the original tracking problem is transformed into the optimal tracking problem for a delay-free system with respect to the simplified performance index. The optimal tracking control (OTC) law is obtained from Riccati and Stein equations. The existent and uniqueness of the optimal control law is proved. A reduced-order observer is constructed to solve the problem of physically realizable for the items of the reference input and sinusoidal disturbances. Finally, the feasibility and effectiveness of the proposed approaches are validated by numerical examples.
유성기어형 능동 전륜 조향 시스템을 이용한 조종성과 안정성 향상을 위한 제어알고리즘 개발
신현수(Hyunsoo Shin),김창준(Changjun Kim),미안아쉬팍알리(Mian Ashfaq Ali),한창수(Changsoo Han),오승규(Seungkyu Oh),장진희(Jinhee Jang) 한국자동차공학회 2009 한국자동차공학회 부문종합 학술대회 Vol.2009 No.4
Active Front Steering (AFS) system enables vehicle performance to improve directional stability control and driver convenience. AFS system is a complementary system for a front-steered vehicle that adds compensation angle at lower speed or subtracts at higher speed based on vehicle information and performance such as steering wheel angle, vehicle speed, lateral acceleration, yaw rate and road conditions. In this paper, planetary gear type AFS module modeling is used Bond graph method. Variable Gear Ratio(VGR) algorithm is considered vehicle speed and steering wheel angle for driver’s convenience. Active steering is proposed to improve vehicle yaw stability which use PID controller.
Passivity Based Adaptive Control for Upper Extremity Assist Exoskeleton
한창수,압둘 마난 칸,윤덕원,Mian Ashfaq Ali,Khalil Muhammad Zuhaib,원조,Junaid Iqbal,신규식 제어·로봇·시스템학회 2016 International Journal of Control, Automation, and Vol.14 No.1
Upper limb assist exoskeleton robot requires quantitative techniques to assess human motor function andgenerate command signal for robots to act in compliance with human motion. To asses human motor function,we present Desired Motion Intention (DMI) estimation algorithm using Muscle Circumference Sensor (MCS) andload cells. Here, MCS measures human elbow joint torque using human arm kinematics, biceps/triceps musclemodel and physiological cross sectional area of these muscles whereas load cells play a compensatory role for thetorque generated by shoulder muscles as these cells measure desire of shoulder muscles to move the arm and notthe internal activity of shoulder muscles. Furthermore, damped least square algorithm is used to estimate DesiredMotion Intention (DMI) from these torques. To track this estimated DMI, we have used passivity based adaptivecontrol algorithm. This control techniques is particular useful to adapt modeling error of assist exoskeleton robotfor different subjects. Proposed methodology is experimentally evaluated on seven degree of freedom upper limbassist exoskeleton. Results show that DMI is well estimated and tracked for assistance by the proposed controlalgorithm.