21 research outputs found
Resilient Distributed Energy Management for Systems of Interconnected Microgrids
In this paper, distributed energy management of interconnected microgrids,
which is stated as a dynamic economic dispatch problem, is studied. Since the
distributed approach requires cooperation of all local controllers, when some
of them do not comply with the distributed algorithm that is applied to the
system, the performance of the system might be compromised. Specifically, it is
considered that adversarial agents (microgrids with their controllers) might
implement control inputs that are different than the ones obtained from the
distributed algorithm. By performing such behavior, these agents might have
better performance at the expense of deteriorating the performance of the
regular agents. This paper proposes a methodology to deal with this type of
adversarial agents such that we can still guarantee that the regular agents can
still obtain feasible, though suboptimal, control inputs in the presence of
adversarial behaviors. The methodology consists of two steps: (i) the
robustification of the underlying optimization problem and (ii) the
identification of adversarial agents, which uses hypothesis testing with
Bayesian inference and requires to solve a local mixed-integer optimization
problem. Furthermore, the proposed methodology also prevents the regular agents
to be affected by the adversaries once the adversarial agents are identified.
In addition, we also provide a sub-optimality certificate of the proposed
methodology.Comment: 8 pages, Conference on Decision and Control (CDC) 201
Formation control of mobile robots and unmanned aerial vehicles
In this dissertation, the nonlinear control of nonholonomic mobile robot formations and unmanned aerial vehicle (UAV) formations is undertaken and presented in six papers. In the first paper, an asymptotically stable combined kinematic/torque control law is developed for leader-follower based formation control of mobile robots using backstepping. A neural network (NN) is introduced along with robust integral of the sign of the error (RISE) feedback to approximate the dynamics of the follower as well as its leader using online weight tuning. Subsequently, in the second paper, a novel NN observer is designed to estimate the linear and angular velocities of both the follower and its leader robot and a NN output feedback control law is developed. On the other hand, in the third paper, a NN-based output feedback control law is presented for the control of an underactuated quad rotor UAV, and a NN virtual control input scheme is proposed which allows all six degrees of freedom to be controlled using only four control inputs. The results of this paper are extended to include the control of quadrotor UAV formations, and a novel three-dimensional leader-follower framework is proposed in the fourth paper. Next, in the fifth paper, the discrete-time nonlinear optimal control is undertaken using two online approximators (OLA\u27s) to solve the infinite horizon Hamilton-Jacobi-Bellman (HJB) equation forward-in-time to achieve nearly optimal regulation and tracking control. In contrast, paper six utilizes a single OLA to solve the infinite horizon HJB and Hamilton-Jacobi-Isaacs (HJI) equations forward-intime for the near optimal regulation and tracking control of continuous affine nonlinear systems. The effectiveness of the optimal tracking controllers proposed in the fifth and sixth papers are then demonstrated using nonholonomic mobile robot formation control --Abstract, page iv
Event-triggered near optimal adaptive control of interconnected systems
Increased interest in complex interconnected systems like smart-grid, cyber manufacturing have attracted researchers to develop optimal adaptive control schemes to elicit a desired performance when the complex system dynamics are uncertain. In this dissertation, motivated by the fact that aperiodic event sampling saves network resources while ensuring system stability, a suite of novel event-sampled distributed near-optimal adaptive control schemes are introduced for uncertain linear and affine nonlinear interconnected systems in a forward-in-time and online manner.
First, a novel stochastic hybrid Q-learning scheme is proposed to generate optimal adaptive control law and to accelerate the learning process in the presence of random delays and packet losses resulting from the communication network for an uncertain linear interconnected system. Subsequently, a novel online reinforcement learning (RL) approach is proposed to solve the Hamilton-Jacobi-Bellman (HJB) equation by using neural networks (NNs) for generating distributed optimal control of nonlinear interconnected systems using state and output feedback. To relax the state vector measurements, distributed observers are introduced.
Next, using RL, an improved NN learning rule is derived to solve the HJB equation for uncertain nonlinear interconnected systems with event-triggered feedback. Distributed NN identifiers are introduced both for approximating the uncertain nonlinear dynamics and to serve as a model for online exploration. Next, the control policy and the event-sampling errors are considered as non-cooperative players and a min-max optimization problem is formulated for linear and affine nonlinear systems by using zero-sum game approach for simultaneous optimization of both the control policy and the event based sampling instants. The net result is the development of optimal adaptive event-triggered control of uncertain dynamic systems --Abstract, page iv
Decentralized adaptive neural network control of interconnected nonlinear dynamical systems with application to power system
Traditional nonlinear techniques cannot be directly applicable to control large scale interconnected nonlinear dynamic systems due their sheer size and unavailability of system dynamics. Therefore, in this dissertation, the decentralized adaptive neural network (NN) control of a class of nonlinear interconnected dynamic systems is introduced and its application to power systems is presented in the form of six papers. In the first paper, a new nonlinear dynamical representation in the form of a large scale interconnected system for a power network free of algebraic equations with multiple UPFCs as nonlinear controllers is presented. Then, oscillation damping for UPFCs using adaptive NN control is discussed by assuming that the system dynamics are known. Subsequently, the dynamic surface control (DSC) framework is proposed in continuous-time not only to overcome the need for the subsystem dynamics and interconnection terms, but also to relax the explosion of complexity problem normally observed in traditional backstepping. The application of DSC-based decentralized control of power system with excitation control is shown in the third paper. On the other hand, a novel adaptive NN-based decentralized controller for a class of interconnected discrete-time systems with unknown subsystem and interconnection dynamics is introduced since discrete-time is preferred for implementation. The application of the decentralized controller is shown on a power network. Next, a near optimal decentralized discrete-time controller is introduced in the fifth paper for such systems in affine form whereas the sixth paper proposes a method for obtaining the L2-gain near optimal control while keeping a tradeoff between accuracy and computational complexity. Lyapunov theory is employed to assess the stability of the controllers --Abstract, page iv
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Game-Theoretic Safety Assurance for Human-Centered Robotic Systems
In order for autonomous systems like robots, drones, and self-driving cars to be reliably introduced into our society, they must have the ability to actively account for safety during their operation. While safety analysis has traditionally been conducted offline for controlled environments like cages on factory floors, the much higher complexity of open, human-populated spaces like our homes, cities, and roads makes it unviable to rely on common design-time assumptions, since these may be violated once the system is deployed. Instead, the next generation of robotic technologies will need to reason about safety online, constructing high-confidence assurances informed by ongoing observations of the environment and other agents, in spite of models of them being necessarily fallible.This dissertation aims to lay down the necessary foundations to enable autonomous systems to ensure their own safety in complex, changing, and uncertain environments, by explicitly reasoning about the gap between their models and the real world. It first introduces a suite of novel robust optimal control formulations and algorithmic tools that permit tractable safety analysis in time-varying, multi-agent systems, as well as safe real-time robotic navigation in partially unknown environments; these approaches are demonstrated on large-scale unmanned air traffic simulation and physical quadrotor platforms. After this, it draws on Bayesian machine learning methods to translate model-based guarantees into high-confidence assurances, monitoring the reliability of predictive models in light of changing evidence about the physical system and surrounding agents. This principle is first applied to a general safety framework allowing the use of learning-based control (e.g. reinforcement learning) for safety-critical robotic systems such as drones, and then combined with insights from cognitive science and dynamic game theory to enable safe human-centered navigation and interaction; these techniques are showcased on physical quadrotorsโflying in unmodeled wind and among human pedestriansโand simulated highway driving. The dissertation ends with a discussion of challenges and opportunities ahead, including the bridging of safety analysis and reinforcement learning and the need to ``close the loop'' around learning and adaptation in order to deploy increasingly advanced autonomous systems with confidence
๊ตฌ์กฐ๋ก๋ด์ ์ํ ๊ฐ๊ฑดํ ๊ณ์ธต์ ๋์ ๊ณํ ๋ฐ ์ ์ด
ํ์๋
ผ๋ฌธ(๋ฐ์ฌ) -- ์์ธ๋ํ๊ต๋ํ์ : ๊ณต๊ณผ๋ํ ๊ธฐ๊ณํญ๊ณต๊ณตํ๋ถ, 2021.8. ๋ฐ์ข
์ฐ.Over the last several years, robotics has experienced a striking development, and a new generation of robots has emerged that shows great promise in being able to accomplish complex tasks associated with human behavior. Nowadays the objectives of the robots are no longer restricted to the automaton in the industrial process but are changing into explorers for hazardous, harsh, uncooperative, and extreme environments. As these robots usually operate in dynamic and unstructured environments, they should be robust, adaptive, and reactive under various changing operation conditions.
We propose online hierarchical optimization-based planning and control methodologies for a rescue robot to execute a given mission in such a highly unstructured environment. A large number of degrees of freedom is provided to robots in order to achieve diverse kinematic and dynamic tasks. However, accomplishing such multiple objectives renders on-line reactive motion planning and control problems more difficult to solve due to the incompatible tasks. To address this problem, we exploit a hierarchical structure to precisely resolve conflicts by creating a priority in which every task is achieved as much as possible according to the levels.
In particular, we concentrate on the reasoning about the task regularization to ensure the convergence and robustness of a solution in the face of singularity. As robotic systems with real-time motion planners or controllers often execute unrehearsed missions, a desired task cannot always be driven to a singularity free configuration.
We develop a generic solver for regularized hierarchical quadratic programming without resorting to any off-the-shelf QP solver to take advantage of the null-space projections for computational efficiency. Therefore, the underlying principles are thoroughly investigated. The robust optimal solution is obtained under both equality and inequality tasks or constraints while addressing all problems resulting from the regularization. Especially as a singular value decomposition centric approach is leveraged, all hierarchical solutions and Lagrange multipliers for properly handling the inequality constraints are analytically acquired in a recursive procedure. The proposed algorithm works fast enough to be used as a practical means of real-time control system, so that it can be used for online motion planning, motion control, and interaction force control in a single hierarchical optimization.
Core system design concepts of the rescue robot are presented. The goals of the robot are to safely extract a patient and to dispose a dangerous object instead of humans. The upper body is designed humanoid in form with replaceable modularized dual arms. The lower body is featured with a hybrid tracked and legged mobile platform to simultaneously acquire versatile manipulability and all-terrain mobility. Thus, the robot can successfully execute a driving task, dangerous object manipulation, and casualty extraction missions by changing the pose and modularized equipments in an optimized manner.
Throughout the dissertation, all proposed methods are validated through extensive numerical simulations and experimental tests. We highlight precisely how the rescue robot can execute a casualty extraction and a dangerous object disposal mission both in indoor and outdoor environments that none of the existing robots has performed.์ต๊ทผ์ ๋ฑ์ฅํ ์๋ก์ด ์ธ๋์ ๋ก๋ด์ ๊ธฐ์กด์๋ ์ธ๊ฐ๋ง์ด ํ ์ ์์๋ ๋ณต์กํ ์ผ์ ๋ก๋ด ๋ํ ์ํํ ์ ์์์ ๋ณด์ฌ์ฃผ์๋ค. ํนํ DARPA Robotics Challenge๋ฅผ ํตํด ์ด๋ฌํ ์ฌ์ค์ ์ ํ์ธํ ์ ์์ผ๋ฉฐ, ์ด ๋ก๋ด๋ค์ ๊ณต์ฅ๊ณผ ๊ฐ์ ์ ํํ๋ ํ๊ฒฝ์์ ์๋ํ๋ ์ผ์ ๋ฐ๋ณต์ ์ผ๋ก ์ํํ๋ ์๋ฌด์์ ๋ ๋์๊ฐ ๊ทนํ์ ํ๊ฒฝ์์ ์ธ๊ฐ์ ๋์ ํ์ฌ ์ํํ ์๋ฌด๋ฅผ ์ํํ ์ ์๋ ๋ฐฉํฅ์ผ๋ก ๋ฐ์ ํ๊ณ ์๋ค. ๊ทธ๋์ ์ฌ๋๋ค์ ์ฌ๋ํ๊ฒฝ์์ ์์ ํ๊ณ ์์ ์ ์ ํ๊ฒ ๋์ํ ์ ์๋ ์ฌ๋ฌ ๊ฐ์ง ๋์ ์ค์์ ์คํ ๊ฐ๋ฅ์ฑ์ด ๋์ ๋์ฒ ๋ฐฉ์์ผ๋ก ๋ก๋ด์ ์๊ฐํ๊ฒ ๋์๋ค. ํ์ง๋ง ์ด๋ฌํ ๋ก๋ด์ ๋์ ์ผ๋ก ๋ณํํ๋ ๋น์ ํ ํ๊ฒฝ์์ ์๋ฌด๋ฅผ ์ํํ ์ ์์ด์ผ ํ๊ธฐ ๋๋ฌธ์ ๋ถํ์ค์ฑ์ ๋ํด ๊ฐ๊ฑดํด์ผํ๊ณ , ๋ค์ํ ํ๊ฒฝ ์กฐ๊ฑด์์ ๋ฅ๋์ ์ผ๋ก ๋ฐ์์ ํ ์ ์์ด์ผ ํ๋ค. ๋ณธ ํ์๋
ผ๋ฌธ์์๋ ๋ก๋ด์ด ๋น์ ํ ํ๊ฒฝ์์ ๊ฐ๊ฑดํ๋ฉด์๋ ์ ์์ ์ผ๋ก ๋์ํ ์ ์๋ ์ค์๊ฐ ์ต์ ํ ๊ธฐ๋ฐ์ ๋์ ๊ณํ ๋ฐ ์ ์ด ๋ฐฉ๋ฒ๊ณผ ๊ตฌ์กฐ ๋ก๋ด์ ์ค๊ณ ๊ฐ๋
์ ์ ์ํ๊ณ ์ ํ๋ค.
์ธ๊ฐ์ ๋ง์ ์์ ๋๋ฅผ ๊ฐ์ง๊ณ ์์ผ๋ฉฐ, ํ๋์ ์ ์ ๋์์ ์์ฑํ ๋ ๋ค์ํ ๊ธฐ๊ตฌํ ํน์ ๋์ญํ์ ํน์ฑ์ ๊ฐ์ง๋ ์ธ๋ถ ๋์ ํน์ ์์
์ ์ ์ํ๊ณ , ์ด๋ฅผ ํจ๊ณผ์ ์ผ๋ก ์ข
ํฉํ ์ ์๋ค. ๊ทธ๋ฆฌ๊ณ ํ์ต์ ํตํด ๊ฐ ๋์ ์์๋ค์ ์ต์ ํํ ๋ฟ๋ง ์๋๋ผ ์ํฉ ์ ๋ฐ๋ผ ๊ฐ ๋์ ์์์ ์ฐ์ ์์๋ฅผ ๋ถ์ฌํ์ฌ ์ด๋ฅผ ํจ๊ณผ์ ์ผ๋ก ๊ฒฐํฉํ๊ฑฐ๋ ๋ถ๋ฆฌํ์ฌ ์ค์๊ฐ์ผ๋ก ์ต์ ์ ๋์์ ์์ฑํ๊ณ ์ ์ดํ๋ค. ์ฆ, ์ํฉ์ ๋ฐ๋ผ ์ค์ํ ๋์์์๋ฅผ ์ฐ์ ์ ์ผ๋ก ์ํํ๊ณ ์ฐ์ ์์๊ฐ ๋ฎ์ ๋์์์๋ ๋ถ๋ถ ํน์ ์ ์ฒด์ ์ผ๋ก ํฌ๊ธฐํ๊ธฐ๋ ํ๋ฉด์ ๋งค์ฐ ์ ์ฐํ๊ฒ ์ ์ฒด ๋์์ ์์ฑํ๊ณ ์ต์ ํ ํ๋ค.
์ธ๊ฐ๊ณผ ๊ฐ์ด ๋ค์์ ๋๋ฅผ ๋ณด์ ํ ๋ก๋ด ๋ํ ๊ธฐ๊ตฌํ๊ณผ ๋์ญํ์ ํน์ฑ์ ๊ฐ์ง๋ ๋ค์ํ ์ธ๋ถ ๋์ ํน์ ์์
์ ์์
๊ณต๊ฐ(task space) ํน์ ๊ด์ ๊ณต๊ฐ(configuration space)์์ ์ ์ํ ์ ์์ผ๋ฉฐ, ์ฐ์ ์์์ ๋ฐ๋ผ ์ด๋ฅผ ํจ๊ณผ์ ์ผ๋ก ๊ฒฐํฉํ์ฌ ์ ์ฒด ๋์์ ์ ์ฑํ๊ณ ์ ์ดํ ์ ์๋ค. ์๋ก ์๋ฆฝํ๊ธฐ ์ด๋ ค์ด ๋ก๋ด์ ๋์ ๋ฌธ์ ๋ฅผ ํด๊ฒฐํ๊ธฐ ์ํด ๋์๋ค ์ฌ์ด์ ์ฐ์ ์์๋ฅผ ๋ถ์ฌํ์ฌ ๊ณ์ธต์ ์์ฑํ๊ณ , ์ด์ ๋ฐ๋ผ ๋ก๋ด์ ์ ์ ๋์์ ๊ตฌํํ๋ ๋ฐฉ๋ฒ์ ์ค๋ซ๋์ ์ฐ๊ตฌ๊ฐ ์งํ๋์ด ์๋ค. ์ด๋ฌํ ๊ณ์ธต์ ์ต์ ํ๋ฅผ ์ด์ฉํ๋ฉด ์ฐ์ ์์๊ฐ ๋์ ๋์๋ถํฐ ์์ฐจ์ ์ผ๋ก ์คํํ์ง๋ง, ์ฐ์ ์์๊ฐ ๋ฎ์ ๋์์์๋ค๋ ๊ฐ๋ฅํ ๋ง์กฑ์ํค๋ ์ต์ ์ ํด๋ฅผ ์ฐพ์ ์ ์๋ค.
ํ์ง๋ง ๊ด์ ์ ๊ตฌ๋ ๋ฒ์์ ๊ฐ์ ๋ถ๋ฑ์์ ์กฐ๊ฑด์ด ํฌํจ๋ ๊ณ์ธต์ ์ต์ ํ ๋ฌธ์ ์์ ํน์ด์ ์ ๋ํ ๊ฐ๊ฑด์ฑ๊น์ง ํ๋ณดํ ์ ์๋ ๋ฐฉ๋ฒ์ ๋ํด์๋ ์์ง๊น์ง ๋ง์ ๋ถ๋ถ์ด ๋ฐ ํ์ง ๋ฐ๊ฐ ์๋ค. ๋ฐ๋ผ์ ๋ณธ ํ์๋
ผ๋ฌธ์์๋ ๋ฑ์๊ณผ ๋ถ๋ฑ์์ผ๋ก ํํ๋๋ ๊ตฌ์์กฐ๊ฑด ํน์ ๋์์์๋ฅผ ๊ณ์ธต์ ์ต์ ํ์ ๋์์ ํฌํจ์ํค๊ณ , ํน์ด์ ์ด ์กด์ฌํ๋๋ผ๋ ๊ฐ๊ฑด์ฑ๊ณผ ์๋ ด์ฑ์ ๋ณด์ฅํ๋ ๊ด์ ๊ณต๊ฐ์์์ ์ต์ ํด๋ฅผ ํ๋ณดํ๋๋ฐ ์ง์คํ๋ค. ์๋ํ๋ฉด ๋น์ ํ ์๋ฌด๋ฅผ ์ํํ๋ ๋ก๋ด์ ์ฌ์ ์ ๊ณํ๋ ๋์์ ์ํํ๋ ๊ฒ์ด ์๋ ๋ณํํ๋ ํ๊ฒฝ์กฐ๊ฑด์ ๋ฐ๋ผ ์ค์๊ฐ์ผ๋ก ๋์์ ๊ณํํ๊ณ ์ ์ดํด์ผ ํ๊ธฐ ๋๋ฌธ์ ํน์ด์ ์ด ์๋ ์์ธ๋ก ๋ก๋ด์ ํญ์ ์ ์ดํ๊ธฐ๊ฐ ์ด๋ ต๋ค. ๊ทธ๋ฆฌ๊ณ ์ด๋ ๊ฒ ํน์ด์ ์ ํํผํ๋ ๋ฐฉํฅ์ผ๋ก ๋ก๋ด์ ์ ์ดํ๋ ๊ฒ์ ๋ก๋ด์ ์ด์ฉ์ฑ์ ์ฌ๊ฐํ๊ฒ ์ ํด์ํฌ ์ ์๋ค. ํน์ด์ ๊ทผ๋ฐฉ์์์ ํด์ ๊ฐ๊ฑด์ฑ์ด ๋ณด์ฅ๋์ง ์์ผ๋ฉด ๋ก๋ด ๊ด์ ์ ๊ณผ๋ํ ์๋ ํน์ ํ ํฌ๊ฐ ๋ฐ์ํ์ฌ ๋ก๋ด์ ์๋ฌด ์ํ์ด ๋ถ๊ฐ๋ฅํ๊ฑฐ๋ ํ๊ฒฝ๊ณผ ๋ก๋ด์ ์์์ ์ด๋ํ ์ ์์ผ๋ฉฐ, ๋์๊ฐ ๋ก๋ด๊ณผ ํจ๊ป ์๋ฌด๋ฅผ ์ํํ๋ ์ฌ๋์๊ฒ ์ํด๋ฅผ ๊ฐํ ์๋ ์๋ค.
ํน์ด์ ์ ๋ํ ๊ฐ๊ฑด์ฑ์ ํ๋ณดํ๊ธฐ ์ํด ์ฐ์ ์์ ๊ธฐ๋ฐ์ ๊ณ์ธต์ ์ต์ ํ์ ์ ๊ทํ (regularization)๋ฅผ ํตํฉํ์ฌ ์ ๊ทํ๋ ๊ณ์ธต์ ์ต์ ํ (RHQP: Regularized Hierarchical Quadratic Program) ๋ฌธ์ ๋ฅผ ๋ค๋ฃฌ๋ค. ๋ถ๋ฑ์์ด ํฌํจ๋ ๊ณ์ธต์ ์ต์ ํ์ ์ ๊ทํ๋ฅผ ๋์์ ๊ณ ๋ คํจ์ผ๋ก์จ ์ผ๊ธฐ๋๋ ๋ง์ ๋ฌธ์ ์ ๋ค์ ํด๊ฒฐํ๊ณ ํด์ ์ต์ ์ฑ๊ณผ ๊ฐ๊ฑด์ฑ์ ํ๋ณดํ ์ ์๋ ๋ฐฉ๋ฒ์ ์ ์ํ๋ค. ํนํ ์ธ๋ถ์ ์ต์ ํ ํ๋ก๊ทธ๋จ์ ์ฌ์ฉํ์ง ์๊ณ ์์น์ ์ต์ ํ (numerical optimization) ์ด๋ก ๊ณผ ์ฐ์ ์์์ ๊ธฐ๋ฐ์ ๋๋ ์ฌ์ ์์ ๋ ๋ก๋ด์ ํด์ ๊ธฐ๋ฒ์ ์ด์ฉํ์ฌ ๊ณ์ฐ์ ํจ์จ์ฑ์ ๊ทน๋ํํ ์ ์๋ ์ด์ฐจ ํ๋ก๊ทธ๋จ(quadratic programming)์ ์ ์ํ๋ค. ๋ํ ์ด์ ๋์์ ์ ๊ทํ๋ ๊ณ์ธต์ ์ต์ ํ ๋ฌธ์ ์ ์ด๋ก ์ ๊ตฌ์กฐ๋ฅผ ์ฒ ์ ํ๊ฒ ๋ถ์ํ๋ค. ํนํ ํน์ด๊ฐ ๋ถํด (singular value decomposition)๋ฅผ ํตํด ์ต์ ํด์ ๋ถ๋ฑ์ ์กฐ๊ฑด์ ์ฒ๋ฆฌํ๋๋ฐ ํ์ํ ๋ผ๊ทธ๋์ง ์น์๋ฅผ ์ฌ๊ท์ ์ธ ๋ฐฉ๋ฒ์ผ๋ก ํด์์ ํํ๋ก ๊ตฌํจ์ผ๋ก์จ ๊ณ์ฐ์ ํจ์จ์ฑ์ ์ฆ๋์ํค๊ณ ๋์์ ๋ถ๋ฑ์์ ์กฐ๊ฑด์ ์ค๋ฅ ์์ด ์ ํํ๊ฒ ์ฒ๋ฆฌํ ์ ์๋๋ก ํ์๋ค. ๊ทธ๋ฆฌ๊ณ ์ ๊ทํ๋ ๊ณ์ธต์ ์ต์ ํ๋ฅผ ํ์ ์ด๊น์ง ํ์ฅํ์ฌ ํ๊ฒฝ๊ณผ ๋ก๋ด์ ์์ ํ ์ํธ์์ฉ์ ๋ณด์ฅํ์ฌ ๋ก๋ด์ด ์ ์ ํ ํ์ผ๋ก ํ๊ฒฝ๊ณผ ์ ์ดํ ์ ์๋๋ก ํ์๋ค.
๋ถํ์ค์ฑ์ด ์กด์ฌํ๋ ๋น์ ํ ํ๊ฒฝ์์ ๋น์ ํ ์๋ฌด๋ฅผ ์ํํ ์ ์๋ ๊ตฌ์กฐ๋ก๋ด์ ํต์ฌ ์ค๊ณ ๊ฐ๋
์ ์ ์ํ๋ค. ๋น์ ํ ํ๊ฒฝ์์์ ์กฐ์ ์ฑ๋ฅ๊ณผ ์ด๋ ์ฑ๋ฅ์ ๋์์ ํ๋ณดํ ์ ์๋ ํ์์ผ๋ก ๋ก๋ด์ ์ค๊ณํ์ฌ ๊ตฌ์กฐ ๋ก๋ด์ผ๋ก ํ์ฌ๊ธ ์ต์ข
๋ชฉ์ ์ผ๋ก ์ค์ ๋ ์ธ๊ฐ์ ๋์ ํ์ฌ ๋ถ์์๋ฅผ ๊ตฌ์กฐํ๊ณ ์ํ๋ฌผ์ ์ฒ๋ฆฌํ๋ ์๋ฌด๋ฅผ ํจ๊ณผ์ ์ผ๋ก ์ํํ ์ ์๋๋ก ํ๋ค. ๊ตฌ์กฐ ๋ก๋ด์ ํ์ํ ๋งค๋ํฐ๋ ์ดํฐ๋ ๋ถ์์ ๊ตฌ์กฐ ์๋ฌด์ ์ํ๋ฌผ ์ฒ๋ฆฌ ์๋ฌด์ ๋ฐ๋ผ ๊ต์ฒด ๊ฐ๋ฅํ ๋ชจ๋ํ์ผ๋ก ์ค๊ณํ์ฌ ๊ฐ๊ฐ์ ์๋ฌด์ ๋ฐ๋ผ ์ต์ ํ๋ ๋งค๋ํฐ ๋ ์ดํฐ๋ฅผ ์ฅ์ฐฉํ์ฌ ์๋ฌด๋ฅผ ์ํํ ์ ์๋ค. ํ์ฒด๋ ํธ๋๊ณผ ๊ด์ ์ด ๊ฒฐํฉ๋ ํ์ด๋ธ๋ฆฌ๋ ํํ๋ฅผ ์ทจํ๊ณ ์์ผ๋ฉฐ, ์ฃผํ ์๋ฌด์ ์กฐ์์๋ฌด์ ๋ฐ๋ผ ํ์์ ๋ณ๊ฒฝํ ์ ์๋ค. ํ์ ๋ณ๊ฒฝ๊ณผ ๋ชจ๋ํ๋ ๋งค๋ํฐ๋ ์ดํฐ๋ฅผ ํตํด์์กฐ์ ์ฑ๋ฅ๊ณผ ํํ ์งํ์์ ์ด๋ํ ์ ์๋ ์ฃผํ ์ฑ๋ฅ์ ๋์์ ํ๋ณดํ์๋ค.
์ต์ข
์ ์ผ๋ก ๊ตฌ์กฐ๋ก๋ด์ ์ค๊ณ์ ์ค์๊ฐ ๊ณ์ธต์ ์ ์ด๋ฅผ ์ด์ฉํ์ฌ ๋น์ ํ ์ค๋ด์ธ ํ๊ฒฝ์์ ๊ตฌ์กฐ๋ก๋ด์ด ์ฃผํ์๋ฌด, ์ํ๋ฌผ ์กฐ์์๋ฌด, ๋ถ์์ ๊ตฌ์กฐ ์๋ฌด๋ฅผ ์ฑ๊ณต์ ์ผ๋ก ์ ํํ ์ ์์์ ํด์๊ณผ ์คํ์ ํตํ์ฌ ์
์ฆํจ์ผ๋ก์จ ๋ณธ ํ์๋
ผ๋ฌธ์์ ์ ์ํ ์ค๊ณ์ ์ ๊ทํ๋ ๊ณ์ธต์ ์ต์ ํ ๊ธฐ๋ฐ์ ์ ์ด ์ ๋ต์ ์ ์ฉ์ฑ์ ๊ฒ์ฆํ์๋ค.1 Introduction 1
1.1 Motivations 1
1.2 Related Works and Research Problems for Hierarchical Control 3
1.2.1 Classical Approaches 3
1.2.2 State-of-the-Art Strategies 4
1.2.3 Research Problems 7
1.3 Robust Rescue Robots 9
1.4 Research Goals 12
1.5 Contributions of ThisThesis 13
1.5.1 Robust Hierarchical Task-Priority Control 13
1.5.2 Design Concepts of Robust Rescue Robot 16
1.5.3 Hierarchical Motion and ForceControl 17
1.6 Dissertation Preview 18
2 Preliminaries for Task-Priority Control Framework 21
2.1 Introduction 21
2.2 Task-Priority Inverse Kinematics 23
2.3 Recursive Formulation of Null Space Projector 28
2.4 Conclusion 31
3 Robust Hierarchical Task-Priority Control 33
3.1 Introduction 33
3.1.1 Motivations 35
3.1.2 Objectives 36
3.2 Task Function Approach 37
3.3 Regularized Hierarchical Optimization with Equality Tasks 41
3.3.1 Regularized Hierarchical Optimization 41
3.3.2 Optimal Solution 45
3.3.3 Task Error and Hierarchical Matrix Decomposition 49
3.3.4 Illustrative Examples for Regularized Hierarchical Optimization 56
3.4 Regularized Hierarchical Optimization with Inequality Constraints 60
3.4.1 Lagrange Multipliers 61
3.4.2 Modified Active Set Method 66
3.4.3 Illustrative Examples of Modified Active Set Method 70
3.4.4 Examples for Hierarchical Optimization with Inequality Constraint 72
3.5 DLS-HQP Algorithm 79
3.6 Concluding Remarks 80
4 Rescue Robot Design and Experimental Results 83
4.1 Introduction 83
4.2 Rescue Robot Design 85
4.2.1 System Design 86
4.2.2 Variable Configuration Mobile Platform 92
4.2.3 Dual Arm Manipulators 95
4.2.4 Software Architecture 97
4.3 Performance Verification for Hierarchical Motion Control 99
4.3.1 Real-Time Motion Generation 99
4.3.2 Task Specifications 103
4.3.3 Singularity Robust Task Priority 106
4.3.4 Inequality Constraint Handling and Computation Time 111
4.4 Singularity Robustness and Inequality Handling for Rescue Mission 117
4.5 Field Tests 122
4.6 Concluding Remarks 126
5 Hierarchical Motion and Force Control 129
5.1 Introduction 129
5.2 Operational Space Control 132
5.3 Acceleration-Based Hierarchical Motion Control 134
5.4 Force Control 137
5.4.1 Force Control with Inner Position Loop 141
5.4.2 Force Control with Inner Velocity Loop 144
5.5 Motion and Force Control 145
5.6 Numerical Results for Acceleration-Based Motion and Force Control 148
5.6.1 Task Specifications 150
5.6.2 Force Control Performance 151
5.6.3 Singularity Robustness and Inequality Constraint Handling 155
5.7 Velocity Resolved Motion and Force Control 160
5.7.1 Velocity-Based Motion and Force Control 161
5.7.2 Experimental Results 163
5.8 Concluding Remarks 167
6 Conclusion 169
6.1 Summary 169
6.2 Concluding Remarks 173
A Appendix 175
A.1 Introduction to PID Control 175
A.2 Inverse Optimal Control 176
A.3 Experimental Results and Conclusion 181
Bibliography 183
Abstract 207๋ฐ
Nonlinear Model Predictive Control for Motion Generation of Humanoids
Das Ziel dieser Arbeit ist die Untersuchung und Entwicklung numerischer Methoden zur Bewegungserzeugung von humanoiden Robotern basierend auf nichtlinearer modell-prรคdiktiver Regelung. Ausgehend von der Modellierung der Humanoiden als komplexe Mehrkรถrpermodelle, die sowohl durch unilaterale Kontaktbedingungen beschrรคnkt als auch durch die Formulierung unteraktuiert sind, wird die Bewegungserzeugung als Optimalsteuerungsproblem formuliert.
In dieser Arbeit werden numerische Erweiterungen basierend auf den Prinzipien der Automatischen Differentiation fรผr rekursive Algorithmen, die eine effiziente Auswertung der dynamischen Grรถรen der oben genannten Mehrkรถrperformulierung erlauben, hergeleitet, sodass sowohl die nominellen Grรถรen als auch deren ersten Ableitungen effizient ausgewertet werden kรถnnen. Basierend auf diesen Ideen werden Erweiterungen fรผr die Auswertung der Kontaktdynamik und der Berechnung des Kontaktimpulses vorgeschlagen.
Die Echtzeitfรคhigkeit der Berechnung von Regelantworten hรคngt stark von der Komplexitรคt der fรผr die Bewegungerzeugung gewรคhlten Mehrkรถrperformulierung und der zur Verfรผgung stehenden Rechenleistung ab. Um einen optimalen Trade-Off zu ermรถglichen, untersucht diese Arbeit einerseits die mรถgliche Reduktion der Mehrkรถrperdynamik und andererseits werden maรgeschneiderte numerische Methoden entwickelt, um die Echtzeitfรคhigkeit der Regelung zu realisieren.
Im Rahmen dieser Arbeit werden hierfรผr zwei reduzierte Modelle hergeleitet: eine nichtlineare Erweiterung des linearen inversen Pendelmodells sowie eine reduzierte Modellvariante basierend auf der centroidalen Mehrkรถrperdynamik. Ferner wird ein Regelaufbau zur GanzkรถrperBewegungserzeugung vorgestellt, deren Hauptbestandteil jeweils aus einem speziell diskretisierten Problem der nichtlinearen modell-prรคdiktiven Regelung sowie einer maรgeschneiderter Optimierungsmethode besteht. Die Echtzeitfรคhigkeit des Ansatzes wird durch Experimente mit den Robotern HRP-2 und HeiCub verifiziert.
Diese Arbeit schlรคgt eine Methode der nichtlinear modell-prรคdiktiven Regelung vor, die trotz der Komplexitรคt der vollen Mehrkรถrperformulierung eine Berechnung der Regelungsantwort in Echtzeit ermรถglicht. Dies wird durch die geschickte Kombination von linearer und nichtlinearer modell-prรคdiktiver Regelung auf der aktuellen beziehungsweise der letzten Linearisierung des Problems in einer parallelen Regelstrategie realisiert. Experimente mit dem humanoiden Roboter Leo zeigen, dass, im Vergleich zur nominellen Strategie, erst durch den Einsatz dieser Methode eine Bewegungserzeugung auf dem Roboter mรถglich ist.
Neben Methoden der modell-basierten Optimalsteuerung werden auch modell-freie Methoden des verstรคrkenden Lernens (Reinforcement Learning) fรผr die Bewegungserzeugung untersucht, mit dem Fokus auf den schwierig zu modellierenden Modellunsicherheiten der Roboter.
Im Rahmen dieser Arbeit werden eine allgemeine vergleichende Studie sowie Leistungskennzahlen entwickelt, die es erlauben, modell-basierte und -freie Methoden quantitativ bezรผglich ihres Lรถsungsverhaltens zu vergleichen. Die Anwendung der Studie auf ein akademisches Beispiel zeigt Unterschiede und Kompromisse sowie Break-Even-Punkte zwischen den Problemformulierungen.
Diese Arbeit schlรคgt basierend auf dieser Grundlage zwei mรถgliche Kombinationen vor, deren Eigenschaften bewiesen und in Simulation untersucht werden. Auรerdem wird die besser abschneidende Variante auf dem humanoiden Roboter Leo implementiert und mit einem nominellen
modell-basierten Regler verglichen
CONTROLLER SYNTHESIS AND FORMAL BEHAVIOR INFERENCE IN AUTONOMOUS SYSTEMS
Autonomous systems are widely used in crucial applications such as surveillance,defense, reghting, and search & rescue operations. Many of these application
require systems to satisfy user-dened requirements describing the desired
system behavior. Given high-level requirements, we are interested in the design of
controllers that guarantee the compliance of these requirements by the system. However,
ensuring that these systems satisfy a given set of requirements is challenging
for many reasons, one of which is the large computational cost incurred by having
to account for all possible system behaviors and environment conditions. These
computational diculties are exacerbated when systems are required to satisfy requirements
involving large numbers of tasks emerging from dynamic environments.
In addition to computational diculties, scalability issues also arise when dealing
with multi-agent applications, in which agents require coordination and communication
to satisfy mission requirements. This dissertation is an eort towards addressing
the computational and scalability challenges of designing controllers from highlevel
requirements by employing reactive synthesis, a formal methods approach, and combining it with other decision-making processes that handle coordination among
agents to alleviate the load on reactive synthesis. The proposed framework results
in a more scalable solution with lower computational costs while guaranteeing that
high-level requirements are met. The practicality of the proposed framework is
demonstrated through various types of multi-agent applications including reghting,
re monitoring, rescue, search & rescue and ship protection scenarios.
Our approach incorporates methodology from computer science and control,
including reactive synthesis of discrete systems, metareasoning, reachability analysis
and inverse reinforcement learning. This thesis consists of two key parts: reactive
synthesis from linear temporal logic specications and specication inference
from demonstrations of formal behavior. First, we introduce the reactive synthesis
problem for which the desired system behavior species the method by which
a multi-agent system solves the problem of decentralized task allocation depending
on communication availability conditions. Second, we present the synthesis problem
formulated to obtain a high-level mission planner and controller for managing a
team of agents ghting a wildre. Third, we present a framework for inferring linear
temporal logic specications that succinctly convey and explain the observed behavior.
The gained knowledge is leveraged to improve motion prediction for agents
behaving according to the learned specication. The eectiveness of the inference
process and motion prediction framework are demonstrated through a scenario in
which humans practice social norms commonly seen in pedestrian settings