In human-robot shared control, control authority is shared between human operators and automatic systems. Switching from one state to another can make the overall system unstable, even though the stability in each sta...
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ISBN:
(纸本)9780791851890
In human-robot shared control, control authority is shared between human operators and automatic systems. Switching from one state to another can make the overall system unstable, even though the stability in each state is guaranteed. This issue is investigated in simulation using a Lane Keeping Assist System (LKAS), which guides a vehicle along a lane, while allowing lane changes, if desired by the human. An interface allows a human to input a steering control signal with a joystick and provides visual feedback of lane-position. The total steering command is the combination of the LKAS control signal and the human steering input. System performance is explored as the vehicle switches among different levels of cooperation between the human and the automatic driving system. The minimum time permitted between lane changes is an important parameter. As this time is decreased, user intent and the automatic controller are in conflict more often, resulting in larger control efforts from both user and automatic controller.
In this paper, we consider the control design for manipulator handling a flexible payload in the presence of input constraints. The dynamics of the system is described by coupled ordinary differential equation and a p...
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ISBN:
(纸本)9780791851913
In this paper, we consider the control design for manipulator handling a flexible payload in the presence of input constraints. The dynamics of the system is described by coupled ordinary differential equation and a partial differential equation. Considering actuators saturation, the proposed control law applies a smooth hyperbolic function to handle the effect of the input constraints. The asymptotic stability of the closed-loop system is proved by using semi group theory and extended LaSalle' s Invariance Principle. Simulation results show that the proposed controller is effective.
A majority of the results in the literature on hopping robots assume the ground to be rigid. Hopping on a foundation that can be modeled as a mass-spring-damper system poses challenges due to undesired vibration of th...
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ISBN:
(纸本)9780791851890
A majority of the results in the literature on hopping robots assume the ground to be rigid. Hopping on a foundation that can be modeled as a mass-spring-damper system poses challenges due to undesired vibration of the additional degree-of-freedom and dissipation due to impact and viscous damping. A hybrid control strategy is developed to converge the maximum jumping height of the center-of-mass of a two-link prismatic-joint robot to a desired value. The hybrid control strategy uses backstepping in continuous time and integral control in discrete time to control the internal degree-of-freedom and the total energy. Simulation results are presented to demonstrate the efficacy of the controller.
Recent works by the authors have presented modeling and simulation techniques for analyzing repeated fast dynamic loading of thin-film solid-state batteries. These techniques were developed to address timescale issues...
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ISBN:
(纸本)9780791851906
Recent works by the authors have presented modeling and simulation techniques for analyzing repeated fast dynamic loading of thin-film solid-state batteries. These techniques were developed to address timescale issues in modeling battery discharge under these types of loads. In this paper, we explore various consequences of battery usage in potential micro-robotic applications based on use of these modeling techniques in a series of case studies. Impact of electrochemical versus simple lumped parameter battery modeling is first examined. This is followed by projection of battery performance in basic series versus boost converter arrangements to supply thin-film piezoelectric robotic actuators. Potentially advantageous battery and conversion circuit configurations are identified.
In this paper we propose an iterative learning control (ILC) algorithm for a class of periodic processes with a variable time-delay that is greater than one iteration in length. We estimate the delay by separating it ...
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ISBN:
(纸本)9780791851906
In this paper we propose an iterative learning control (ILC) algorithm for a class of periodic processes with a variable time-delay that is greater than one iteration in length. We estimate the delay by separating it into two components: an estimate based on the number of iterations contained within a single delay period and an estimate defined as the residual between the actual delay and the iteration-based estimate. This structure enables the derivation of a stability law for an ILC algorithm that is a function of the delay estimation error. The proposed ILC algorithm is then applied to twin roll strip casting and the results are validated using experimental process data. We also demonstrate the sensitivity of the ILC algorithm to estimation error through simulation results.
In previous work, a (smooth) finite-time distributed control algorithm with time transformation was introduced for first order multiagent systems, which guarantees convergence of the single state of agents to a time-v...
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ISBN:
(纸本)9780791851913
In previous work, a (smooth) finite-time distributed control algorithm with time transformation was introduced for first order multiagent systems, which guarantees convergence of the single state of agents to a time-varying leader at a-priori given, user-defined time T from any arbitrary initial conditions with bounded local control signals. In this paper, we present an extension of this previous work to second-order multiagent systems. Specifically, utilizing a user-defined finite-time interval of interest t is an element of [0, T), we time transform this class of multiagent systems subject to the considered (smooth) distributed control algorithm to an infinite-time interval s is an element of [0, infinity) with s being the stretched time. Based on a property of this time transformation, this results in finite-time convergence as the regular time t approaches to T from any arbitrary initial conditions with bounded local control and internal signals. Finally, two numerical examples illustrate the efficacy of the proposed algorithm.
The Chaplygin beanie is a single-input robotic vehicle for which partial planar motion control can be achieved by exploiting a simple nonholonomic constraint. A previous paper suggested a strategy for such motion cont...
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ISBN:
(纸本)9780791851913
The Chaplygin beanie is a single-input robotic vehicle for which partial planar motion control can be achieved by exploiting a simple nonholonomic constraint. A previous paper suggested a strategy for such motion control. In the present paper, this strategy is validated experimentally and extended to the context of multi-vehicle coordination. It is then shown that when the plane on which two such vehicles operate is translationally compliant, energy transfer between the two can enable a mechanism whereby one (operating under control) may entrain the other (operating passively), partly coordinating their motion. As an extension to this result, it is further demonstrated that a pair of passive vehicles operating on a translationally compliant platform can eventually attain the same heading when released from their deformed configurations.
This paper presents a many-objective optimal design of a four-degree-of-freedom passive suspension system with an inerter device. In the optimization process, four objectives are considered: passenger's head accel...
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ISBN:
(纸本)9780791851913
This paper presents a many-objective optimal design of a four-degree-of-freedom passive suspension system with an inerter device. In the optimization process, four objectives are considered: passenger's head acceleration (HA), crest factor (CF), suspension deflection (SD), and tire deflection (TD). The former two objectives are important for the health and comfort of the driver and the latter two quantify the suspension system performance. The spring Ics and damping cs constants between the sprung mass and unsprung mass, the inertance coefficient B, and the tire spring constant Icy are considered as design parameters. The non-dominated sorting genetic algorithm (NSGA-II) is used to solve this optimization problem. The results show that there are many optimal trade-offs among the design objectives that could be applicable to suspension design in the industry.
The interest in autonomous electrified vehicles has rapidly increased in recent years. In this paper, a speed trajectory generation method based on speed and road grade preview over a short horizon is presented, to im...
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ISBN:
(纸本)9780791851890
The interest in autonomous electrified vehicles has rapidly increased in recent years. In this paper, a speed trajectory generation method based on speed and road grade preview over a short horizon is presented, to improve energy efficiency of the autonomous power split HEV and BEV. The speed trajectory is generated by minimizing the required cumulative over the the horizon wheel power, including regenerative power. We confirm by simulations that the generated speed profiles improve MPG (or MPGe) even though only a short horizon preview information is used with small deviation permitted from the nominal speed profile.
An economic model predictive control framework is presented in this study for an integrated wind turbine and flywheel energy storage system. The control objective is to smooth wind power output and mitigate tower fati...
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ISBN:
(纸本)9780791851906
An economic model predictive control framework is presented in this study for an integrated wind turbine and flywheel energy storage system. The control objective is to smooth wind power output and mitigate tower fatigue load. The optimal control problem within the model predictive control framework has been formulated as a convex optimal control problem with linear dynamics and convex constraints that can be solved globally. The performance of the proposed control algorithm is compared to that of a standard wind turbine controller The effect of the proposed control actions on the fatigue loads acting on the tower and blades is studied. The simulation results, with various wind scenarios, showed the ability of the proposed control algorithm to achieve the aforementioned objectives in terms of smoothing output power and mitigating tower fatigue load at the cost of a minimal reduction of the wind energy harvested.
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