Practical steering control for an autonomous docking based Akihiro YAMANASHI Advancsd Smart Mobility Co., Ltd 1 Outline • Background • Motivation and Purpose • Steering control • Experiments • Conclusions 2 Next Generation Urban Transportation System Concept - ART: Advanced Rapid Transit Japanese government initiated a research project on automated driving systems under CrossMinisterial Strategic Innovation Promotion Program (SIP). ART will expand from the traditional limited operations to provide more transportation convenient service in advanced road transportation systems. Especially, automation of a high-precision docking to bus stop is required. 3 Experimental step and gap limit evaluation to establish wheelchair friendly conditions Research subjects: 12-persons (6 male and 6 female) Age-range: 20-60 years Experimental verdict: Step value:3cm Gap value:6cm Estimate index MANUAL WHEELCHAIR EXPERIMENT IMAGE ELECTRIC WHEELCHAIR ○ Easy access △ Requires some effort (reasonable) ▼ Outer limit X Assistance required １．The allowable step limit MANUAL WHEELCHAIR Step value 6mm 18mm 30mm 42mm A ○ ○ △ X B ○ ○ △ ▼ C ○ ○ ○ ▼ D ○ ○ ○ ▼ E ○ ○ X X Evaluation F ○ ○ △ ▼ ○ ○ △ X Step value 6mm 18mm 30mm 42mm ELECTRIC WHEELCHAIR A B C D E F ○ ○ △ X ○ ○ ○ ▼ ○ ○ ○ ▼ ○ ○ ○ ▼ ○ △ ○ X ○ ○ ○ ▼ Evaluation ○ ○ ○ X ２．The allowable gap limit Gap value 30mm 45mm 60mm 75mm MANUAL WHEELCHAIR A B C D E F ○ ○ ○ ▼ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ▼ ○ ○ ○ ▼ ○ ○ ○ △ Evaluation Gap value ○ ○ ○ ▼ 30mm 45mm 60mm 75mm ELECTRIC WHEELCHAIR A B C D E F ○ ○ △※ X※ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ○ ▼ ○ ○ ○ ▼ ○ ○ ○ ▼ ※front wheels to fall into the gap Evaluation ○ ○ ○ ▼ 4 Control System for Autonomous Docking c K 2 e2 vr K 3 sin e3 vr v cos e3 Target trajectory (Geometrically programed coordinates) Control Model Steering motors Counter-Steering feedforward controller Total distance (Starting point) Inclination of target trajectory Deviation of target trajectory ＋ ＋ Feedback control of Steering ー ＋ ー Target trajectory Target deviation （0cm） ＋ Lane Keeping for Automatic Steering • In general, a camera foresees the lane marker . • There are some driver model to control the vehicle position. • It is difficult to see a marker in various situations: weather cond., close space. • Another way is to see the lane marker in just side of the vehicle. 6 Control with Road white line Camera position １．Near the Vehicle rear door Position of Guided white line Guided white line (the virtual reference trajectory) merit and demerit ○Merit ・Performance improvement near the rear door ○Demerit ・draw a white line at the bus stop ２．Near the Vehicle tip center ○Merit ・Feedback control with white line is always possible ○Demerit ・Performance drops near the rear door ・Mixed with ordinary road white lines ３．Near the front left end of the vehicle ○Merit ・Feedback control with white line is always possible ○Demerit ・Performance drops near the rear door Since it is difficult to realize No.1,2, it is evaluated at No3 Test Bus and System Architecture Cameras Cameras Wheel speed sensors EBS Yaw rate sensors Image Processing by PC Steering motors dSPACE Autobox 8 Experiments • The operations of acceleration and deceleration are performed manually by a driver • Only the steering is controlled • The velocity of the truck is from 20 or 30 km/h to 0 km/h • The controlled bus follows to the reference trajectory and the reference heading angle determined from the results of manual operation. • The reference trajectories are three types Type 1 Type 2 Type 3 Reference trajectory Type1 ●The error to target is ±0.02m Front door Front door error to target [m] 0.05 -0.01 0.02 0.03 0 1 -0.002 2 3 -0.009 -0.008 4 平均 5 -0.03 -0.02 -0.02 -0.002 -0.015 error to target [m] 1回目 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 -0.01 -0.02 -0.03 2 3 -0.007 4 5 平均 -0.008 -0.015 -0.015 -0.018 -0.027 error to target [m] Rear door 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 2回目 3回目 4回目 5回目 平均 Central door 0.02 0.015 0.01 0.003 -0.005 -0.025 1回目 1 -0.02 -0.05 -0.03 0 0.005 -0.01 -0.0098 -0.01 0.00 0.01 2回目 3回目 4回目 5回目 平均 -0.005 -0.002 5回目 平均10 Rear door 0.01 0.015 0.01 -0.04 1回目 2回目 3回目 4回目 Reference trajectory Type2 ●The error to target is ±0.02m Front door Front door 0.051 0.036 0.04 0.021 0.021 0.02 0.025 0 1 -0.004 2 3 4 5 error to target [m] 0.06 平均 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 -0.04 2回目 -0.02 3回目 4回目 5回目 -0.014 平均 error to target [m] Central door Rear door0.036 0.001 0.02 0.014 0.0078 -0.004 1 2 3 4 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 0.00 5 -0.02 -0.024 平均 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 0.00 0.01 0.005 0.00 4回目 5回目 平均 0.01 0.01 -0.015 1回目 error to target [m] 0.04 -0.04 -0.005 -0.01 1回目 -0.02 0 0.005 2回目 3回目 Rear door 0.00 -0.01 1回目 -0.002 -0.02 2回目 3回目 4回目 5回目 平均 11 Reference trajectory Type3 ●The error to target is ±0.02m Front door 0.05 0.002 0.015 -0.02 2 -0.011 -0.022 0 1 -0.02 Front door 0 3 4 5 -0.009 平均 -0.0108 -0.028 -0.021 -0.024 5回目 平均 -0.04 -0.06 -0.04 -0.05 -0.04 1回目 2回目 3回目 4回目 Central door 0.06 0.04 0.02 0 -0.02 -0.04 -0.06 Rear door 0.025 0.03 0.01 0.02 -0.02 2回目 0.01 0.04 3回目 0.042 0.037 2 3 4 -0.008 5 平均 4回目 0.049 0.010 5回目 平均 0.044 0.038 0.018 0.02 1 0.014 Rear door 0.06 0.0164 0.02 -0.002 1回目 0 -0.01 0.005 0.035 0.04 0.02 0.014 0 1回目 2回目 3回目 4回目 5回目 平均 12 Experimental Results Stopping Distance [cm] Type of vehicle Bus Reference trajectories Type 1 Type 2 Type 3 Articulated bus Door position Maximal value plus direction/minus direction Average (N=5) Maximal value plus direction/minus direction Front door 0/-2.0 -1.0 -1.1 / -4.0 -2.4 +2.0 / -0.2 1.0 Central door Average (N=5) Rear door 0/-2.7 -1.5 +4.9 / +1.8 3.8 Front door +5.1/-0.5 2.5 +0.5 / -4.0 -1.4 +1.0 / -1.5 0.0 Central door Rear door +3.6/-2.4 0.8 +1.0 / -2.0 -0.2 Front door +1.5/-4.0 -1.1 +2.0 / -2.0 -0.02 +2.0 / -2.5 0.03 +1.5 / -4.0 -0.02 Central door Rear door +3.5/-0.8 1.6 13 Conclusions • As experimental performance evaluation on autonomous precision docking, the method of the autonomous precision docking based on path following control was described. • The effectiveness of the proposed method was evaluated by the experimental results. • We confirm that the controlled truck docked with precision within about ±0.05m in the virtual reference trajectories of three types. Thank you for your attention! Advancsd Smart Mobility Co., Ltd Akihiro YAMANASHI E-mail : [email protected]
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