In space teleoperation under time delay, performance differs significantly for the various control techniques, for example, 1) compliance control by a position/orientation command and 2) force control by a force/torqu...
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In space teleoperation under time delay, performance differs significantly for the various control techniques, for example, 1) compliance control by a position/orientation command and 2) force control by a force/torque command. With the latter control technique, the robot arm moves toward the point where the external force/torque applied to the end effector becomes equal to the commanded value. This technique is effective for tracking a restricted trajectory or in peg-in-hole insertion, even though the teleoperation is performed under time delay. The effectiveness of force control is discussed. Experimental results for verification based on an on-orbit experiment for deploying and assembling a truss structure on the Engineering Test Satellite VII (ETS-VII) are presented. To perform the deployable truss operation task within the strongly limited experimental time on ETS-VII, it is necessary to choose the timing of sending commands and the direction of forces in correspondence to the current truss configuration. It is also shown that force control is effective for truss insertion during a truss assembly task, regardless of the time delay.
In this work, the fuel economy of a parallel hybrid electric vehicle is investigated. A vehicle control algorithm which yields operating points where operational cost of HEV is minimal is suggested. The operational co...
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In this work, the fuel economy of a parallel hybrid electric vehicle is investigated. A vehicle control algorithm which yields operating points where operational cost of HEV is minimal is suggested. The operational cost of HEV is decided considering both the cost of fossil fuel consumed by an engine and the cost of electricity consumed by an electric motor. A procedure for obtaining the operating points of minimal fuel consumption is introduced. Simulations are carried out for 3 variations of HEV and the results are compared to the fuel economy of a conventional vehicle in order to investigate the effect of hybridization. Simulation results show that HEV with the vehicle control algorithm suggested in this work has a fuel economy 45% better than the conventional vehicle if braking energy is recuperated fully by regeneration and idling of the engine is eliminated. The vehicle modification is also investigated to obtain the target fuel economy set in PNGV program.
作者：
Lee, AYWertz, JACALTECH
Jet Prop Lab Pasadena CA 91109 USA MIT
Space Syst Lab Cambridge MA 02139 USA
The least-squares estimate of the Cassini spacecraft's inertia matrix obtained through the conservation of angular momentum method just described agrees closely with that determined by the existing method. This ag...
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The least-squares estimate of the Cassini spacecraft's inertia matrix obtained through the conservation of angular momentum method just described agrees closely with that determined by the existing method. This agreement validates the conservation of angular momentum method. Using this method, the moments and products of inertia of a spacecraft could be easily estimated whenever telemetry data associated with slewing the spacecraft by the reaction wheels are available.
Dual-stage actuator design for hard disk drives via composite nonlinear feedback control is presented, which consists of a primary actuator, the voice coil motor and a secondary actuator, the suspension piezoelectric ...
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Dual-stage actuator design for hard disk drives via composite nonlinear feedback control is presented, which consists of a primary actuator, the voice coil motor and a secondary actuator, the suspension piezoelectric microactuator. The first is effective in both track seeking and following stages to produce fast rising time and low overshoot and the latter works in track following stage only to help the primary actuator. The implementations show that the dual-stage actuator does yield better performance compared to the single primary actuator.
The composite nonlinear feedback control technique is developed for a class of linear systems with actuator saturation, which consists of a linear and a nonlinear feedback parts without any switching element. The line...
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In this paper we propose two globally stable control algorithms for robust stabilization of spacecraft in the presence of control input saturation, parametric uncertainty, and external disturbances. The control algori...
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In this paper we propose two globally stable control algorithms for robust stabilization of spacecraft in the presence of control input saturation, parametric uncertainty, and external disturbances. The control algorithms are based on variable structure control design and have the following properties: 1) fast and accurate response in the presence of bounded external disturbances and parametric uncertainty;2) explicit accounting for control input saturation;3) computational simplicity and straightforward tuning. We include a detailed stability analysis for the resulting closed-loop system. The stability proof is based on a Lyapunov-like analysis and the properties of the quaternion representation of spacecraft dynamics. It is also shown that an adaptive version of the proposed controller results in substantially simpler stability analysis and improved overall response. We also include numerical simulations to illustrate the spacecraft performance obtained using the proposed controllers.
作者：
Kang, WSparks, ABanda, SUSN
Postgrad Sch Dept Math Monterey CA 93943 USA USAF
Res Lab Control Sci Div Wright Patterson AFB OH 45433 USA
The problem of formation and reconfiguration of multiple microsatellite systems is addressed. A control scheme called the perceptive frame is adopted that integrates the decentralized feedback of each satellite with o...
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The problem of formation and reconfiguration of multiple microsatellite systems is addressed. A control scheme called the perceptive frame is adopted that integrates the decentralized feedback of each satellite with online sensor information to achieve the goal of formation keeping and intersatellite coordination. The proposed design algorithm has the advantage of relative position keeping and easy formation reconfiguration.
Application of the fuzzy logic intelligent control of space-based systems has received relatively less attention compared to conventional control procedures. Basic concepts involved in development of a hierarchical co...
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Application of the fuzzy logic intelligent control of space-based systems has received relatively less attention compared to conventional control procedures. Basic concepts involved in development of a hierarchical control system using fuzzy logic are explained. Next, fuzzy logic is applied to control a novel two-link robotic arm, composed of revolute and prismatic joints, supported by a mobile base traversing along an orbiting platform. The control system that is developed has three levels. A conventional controller, consisting of the feedback linearization technique combined with proportional-derivative control is used in the bottom level of the hierarchical system, to control the servomotors of the robot. A second layer consists of a servo-expert that preprocesses the high-resolution information coming from joint encoders and extracts the status of the system. A third, intelligent layer is added at the top of the hierarchy to complete the control structure. The main purpose of the top level is to tune the parameters of the crisp (conventional) controller to improve the response of the system. A decision table is developed offline, for tuning the parameters of the crisp (nonfuzzy) controller, which considerably reduces the real-time computational effort. Typical pick-and-place results from the robot are presented that show that extra tuning can significantly improve the performance of the manipulator.
Recent work is presented on the control of a microgripper based on flexure joints, fabricated by LIGA and instrumented with force sensors. The force sensors are semiconductor strain gauges which have been integrated i...
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Recent work is presented on the control of a microgripper based on flexure joints, fabricated by LIGA and instrumented with force sensors. The force sensors are semiconductor strain gauges which have been integrated in the microgripper and experimentally characterised. The microgripper is the core component of a workstation developed to grasp and manipulate tiny objects, such as components of biomedical microdevices. A proportional integral (PI) force control of the microgripper has been implemented. The results of the tracking experiments prove that this control algorithm can assure performance suitable for the intended applications.
A disk type MR fluid damper based on shear mode has been developed and the experimental results show that the dynamic characteristics of a disk-type MR fluid damper can be controlled by the application of an external ...
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ISBN:
(纸本)0819440175
A disk type MR fluid damper based on shear mode has been developed and the experimental results show that the dynamic characteristics of a disk-type MR fluid damper can be controlled by the application of an external magnetic field with a low voltage. In this paper, the effectiveness of on-off control based on feedback of rotational speed, proportional (P) control and proportional-integral (PI) control, both based on feedback of disk vibration eccentricity, on controlling the rotor vibration are experimentally studied. It is shown that the simple on-off control was the most effective method in attaining the required objective, but as expected requires pre-knowledge of the switching speeds and there is a transient response with large amplitude at switching speeds. P and PI control can control the rotor vibrations, but both exhibit significant chattering which can adversely affect the control performance and still require to properly choose the controller parameters.
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