Towards Operating Underactuated Robotic Systems by Going With the Flow- [electronic resource]
Towards Operating Underactuated Robotic Systems by Going With the Flow- [electronic resource]
- 자료유형
- 학위논문파일 국외
- 최종처리일시
- 20240214101656
- ISBN
- 9798380877510
- DDC
- 629.8
- 저자명
- Wiggert, Marius.
- 서명/저자
- Towards Operating Underactuated Robotic Systems by Going With the Flow - [electronic resource]
- 발행사항
- [S.l.]: : University of California, Berkeley., 2023
- 발행사항
- Ann Arbor : : ProQuest Dissertations & Theses,, 2023
- 형태사항
- 1 online resource(134 p.)
- 주기사항
- Source: Dissertations Abstracts International, Volume: 85-06, Section: B.
- 주기사항
- Advisor: Tomlin, Claire.
- 학위논문주기
- Thesis (Ph.D.)--University of California, Berkeley, 2023.
- 사용제한주기
- This item must not be sold to any third party vendors.
- 초록/해제
- 요약Over the centuries, humanity has created ever more ingenious systems to traverse the oceans and skies of our planet. Modern ships and planes operate with powerful engines that require substantial amounts of fuel, leading to high operating costs. However, this approach becomes impractical for applications that require extended periods of autonomous operation without the possibility of refueling. This dissertation starts with the idea of operating systems by going with the flow: harnessing the wind and ocean currents by letting the system drift in favorable directions and strategically using a low-power engine to change flows when this is beneficial. As the power to counteract drag forces scales cubically with the relative velocity of the system, this new paradigm reduces the power required for operation by 2-3 orders of magnitude, thereby significantly reducing the system and operating costs. This could enable a host of novel applications that require low-cost and long-term operations, such as active environmental monitoring of the oceans and atmosphere or floating solar platforms. The primary case study used throughout this work is autonomous seaweed farms that roam the oceans while rapidly growing biomass for biofuel, bioplastic, or to sink it for carbon removal.In this dissertation, we systematically develop control techniques to tackle the four key challenges of operating by going with the flow: First, the system is severely underactuated with its own propulsion often being less than 1/10th of the magnitude of the surrounding flows. Second, to make strategic control decisions when to change flows, only coarse, deterministic forecasts are available. Third, the forecasts have a limited time horizon of 5-10 days, but realistic control objectives extend over weeks to months. Lastly, the forecast error defined as the difference between the forecasted and the true flows often exceeds the propulsion capabilities of the system, hence robust control is infeasible.We start by introducing techniques for continuous-time optimal control when the complex flows are known. We use dynamic programming for the objectives of navigation and maximizing seaweed growth. Next, we turn towards the challenge of operating with imperfect and short-term forecasts. Our insight is that the value functions obtained by the previously developed optimal control methods can be used as closed-loop control policies, which are equivalent to replanning on the forecast at every step. Through extensive simulation studies in realistic ocean conditions, we demonstrate that such frequent replanning allows for reliable operation despite significant forecast errors. To enable reasoning beyond the forecast horizon, we derive a discounted optimal control formulation and demonstrate how the value function can be extended by estimating the cost-to-go using historical flow averages. In the last part of this dissertation, we focus on how to handle constraints in these challenging environments. For that, we integrate time-varying obstacles into our value function and show empirically that this almost eliminates the risk of stranding. Moreover, we develop a hierarchical control approach to operate a fleet of underactuated autonomous systems while avoiding collisions and ensuring connectivity across the fleet.At the end of this dissertation, we summarize our techniques for operating by going with the flow which could enable a host of new applications of low-power autonomous systems in the oceans and skies. We also discuss promising ongoing and future research directions towards further improving the performance of underactuated robotic systems operating in flows.
- 일반주제명
- Robotics.
- 일반주제명
- Computer science.
- 일반주제명
- Electrical engineering.
- 키워드
- Ocean autonomy
- 키워드
- Operating costs
- 키워드
- Flows
- 키워드
- Robotic systems
- 기타저자
- University of California, Berkeley Electrical Engineering & Computer Sciences
- 기본자료저록
- Dissertations Abstracts International. 85-06B.
- 기본자료저록
- Dissertation Abstract International
- 전자적 위치 및 접속
- 로그인 후 원문을 볼 수 있습니다.
Info Détail de la recherche.
- Réservation
- n'existe pas
- My Folder
- Demande Première utilisation
- 비도서대출신청
- 야간 도서대출신청
로그인 후 이용 가능합니다.