Sistem Kendali Heading pada Autonomous Underwater Vehicle

Romdlon Musyaffa Akbar, Oskar Natan, S.ST., MTr.T., Ph.D.; Dr. Andi Dharmawan, S.Si., M.Cs.

2026 | Skripsi | ELEKTRONIKA DAN INSTRUMENTASI

Heading merupakan variabel penting pada Autonomous Underwater Vehicle (AUV) karena menentukan kemampuan wahana dalam mempertahankan arah hadap selama bergerak di bawah air. Penelitian ini bertujuan mengembangkan sistem kendali heading AUV berbasis Linear Quadratic Regulator (LQR) untuk mengurangi miss-heading. Sistem dirancang menggunakan model state-space, Extended Kalman Filter (EKF) sebagai state estimator, dan control allocator untuk mendistribusikan sinyal kendali ke delapan thruster. Pengujian dilakukan melalui karakterisasi thruster, uji kestabilan stasioner, heading hold pada gerak surge  dan sway, serta step-heading dari 0° menuju 180°.

Hasil penelitian menunjukkan bahwa model karakteristik gaya dorong tiap thruster perlu dibedakan karena hubungan PWM dan gaya dorong tidak identik pada setiap aktuator. Pada pengujian kestabilan stasioner, sistem LQR mampu menjaga kedalaman dan orientasi dasar AUV dalam batas toleransi yang ditetapkan, yaitu ±0,12 meter untuk kedalaman, ±4,5° untuk roll dan pitch, serta ±9° untuk yaw. Pada pengujian heading hold, kendali LQR menghasilkan RMSE heading sebesar 1,43° pada gerak surge  dan 1,61° pada gerak sway, jauh lebih kecil dibandingkan kendali konvensional sebesar 46,87° dan 46,34°. Pada pengujian step-heading, LQR menghasilkan rise time sebesar 2,11 detik dan settling time sebesar 4,25 detik pada gerak surge , serta rise time sebesar 1,57 detik dan settling time sebesar 8,61 detik pada gerak sway. Meskipun overshoot pada gerak sway mencapai 72,93°, sistem tetap mampu kembali mendekati referensi akhir dengan steady-state error sebesar -0,16° ± 2,25° dan RMSE yaw rate  sebesar 0,50°/detik. Secara keseluruhan, sistem kendali heading berbasis LQR lebih efektif dalam mengurangi miss-heading dan meredam yaw rate  dibandingkan kendali konvensional berbasis logika kondisional.

Heading is an important variable in an Autonomous Underwater Vehicle (AUV) because it determines the vehicle’s ability to maintain its direction of orientation while moving underwater. This research aims to develop an AUV heading control system based on Linear Quadratic Regulator (LQR) to reduce miss-heading. The system was designed using a state-space model, Extended Kalman Filter (EKF) as the state estimator, and a control allocator to distribute the control signal to eight thrusters. The tests were conducted through thruster characterization, stationary stability testing, heading hold tests during surge  and sway motions, and step-heading tests from 0° to 180°.

The results show that the thrust characteristic model of each thruster needs to be differentiated because the PWM-thrust relationship is not identical for each actuator. In the stationary stability test, the LQR system was able to maintain the AUV depth and basic orientation within the specified tolerance limits, namely ±0.12 meter for depth, ±4.5° for roll and pitch, and ±9° for yaw. In the heading hold test, the LQR controller produced RMSE heading values of 1.43° during surge  motion and 1.61° during sway motion, which were much lower than the conventional controller values of 46.87° and 46.34°. In the step-heading test, the LQR produced a rise time of 2.11 seconds and a settling time of 4.25 seconds during surge  motion, as well as a rise time of 1.57 seconds and a settling time of 8.61 seconds during sway motion. Although the overshoot during sway motion reached 72.93°, the system was still able to return close to the final reference with a steady-state error of -0.16° ± 2.25° and an RMSE yaw rate  of 0.50°/second. Overall, the LQR-based heading control system was more effective in reducing miss-heading and damping yaw rate  compared with the conventional controller based on conditional logic.

Kata Kunci : Autonomous Underwater Vehicle (AUV), heading, miss-heading, Linear Quadratic Regulator, Extended Kalman Filter, state-space