• Title/Summary/Keyword: torque overlay

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Sliding Mode Control for an Electric Power Steering System in an Autonomous Lane Keeping System (자동 차선 유지 시스템의 전기식 파워 조향 시스템을 위한 슬라이딩 모드 제어기)

  • Yu, Jun Young;Kim, Wonhee;Son, Young Seop;Chung, Chung Choo
    • Journal of Institute of Control, Robotics and Systems
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    • v.21 no.2
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    • pp.95-101
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    • 2015
  • In this paper, we develop a sliding mode control for steering wheel angle control based on torque overlay in order to resolve the problem of previous methods for Electric Power Steering (EPS) systems in the Lane Keeping System (LKS) of autonomous vehicles. For the controller design, we propose a 2nd order model of the electric power steering system in an autonomous LKS. The desired state model is designed to prevent a rapid change of the steering wheel angle. The sliding mode steering wheel angle controller is developed for the robustness of the disturbance. Since the proposed method is designed based on torque overlay, torque integration with basic functions of the EPS system for the steering wheel angle control is available for the driver's convenience. The performance of the proposed method was validated via experiments.

Development of a coordinated control algorithm using steering torque overlay and differential braking for rear-side collision avoidance (측후방 충돌 회피를 위한 조향 보조 토크 및 차등 제동 분배 제어 알고리즘 개발)

  • Lee, Junyung;Kim, Dongwook;Yi, Kyongsu;Yoo, Hyunjae;Chong, Hyokjin;Ko, Bongchul
    • Journal of Auto-vehicle Safety Association
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    • v.5 no.2
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    • pp.24-31
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    • 2013
  • This paper describes a coordinated control algorithm for rear-side collision avoidance. In order to assist driver actively and increase driver's safety, the proposed coordinated control algorithm is designed to combine lateral control using a steering torque overlay by Motor Driven Power Steering (MDPS) and differential braking by Vehicle Stability Control (VSC). The main objective of a combined control strategy is twofold. The one is to prevent the collision between the subject vehicle and approaching vehicle in the adjacent lanes. The other is to limit actuator's control inputs and vehicle dynamics to safe values for the assurance of the driver's comfort. In order to achieve these goals, the Lyapunov theory and LMI optimization methods has been employed. The proposed coordinated control algorithm for rear-side collision avoidance has been evaluated via simulation using CarSim and MATLAB/Simulink.

Type of tooth movement during en masse retraction of the maxillary anterior teeth using labial versus lingual biocreative therapy in adults: A randomized clinical trial

  • Sadek, Mais M.;Sabet, Noha E.;Hassan, Islam T.
    • The korean journal of orthodontics
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    • v.49 no.6
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    • pp.381-392
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    • 2019
  • Objective: The objective of this two-arm parallel trial was to compare the type of tooth movement during en masse retraction of the maxillary anterior teeth using labial versus lingual biocreative therapy. Methods: Twenty-eight subjects were randomized in a 1 : 1 ratio to either the labial or lingual group. En masse anterior retraction was performed using labial biocreative therapy in group A and lingual biocreative therapy in group B. Cone beam computed tomography scans were taken before and after retraction and the primary outcome was the type of tooth movement during anterior retraction. Data were analyzed using paired t-tests for comparisons within each group and independent-sample t-test for comparison of the mean treatment changes between the two groups. Results: Significant differences were found between the two groups in relation to the type of tooth movement (labiolingual inclination of the central incisor; mean difference, $5.85{\pm}1.85^{\circ}$). The canine showed significant distal tipping in the lingual group (mean difference, $6.98{\pm}1.25^{\circ}$). The canine was significantly more intruded in the lingual group (mean difference, $1.67{\pm}0.49mm$). Good anchorage control and significant soft tissue changes occurred in both groups. No serious adverse effects were detected. Conclusions: With a 10-mm retraction hook, the labial biocreative technique with the reverse curve overlay provided anterior retraction with good torque control, while in the lingual group, anterior retraction occurred with controlled tipping movement with significant distal tipping and intrusion of the canine (trial registration: The trial was registered at ClinicalTrials.gov [NCT03239275]).