Papers by William Singhose
Journal of Dynamic Systems Measurement and Control-transactions of The Asme, 1999
A method for generating on-ojf command profiles for flexible systems is presented. The command pr... more A method for generating on-ojf command profiles for flexible systems is presented. The command profiles move a system without residual vibration while using a specified amount of actuator fuel. Robustness to modeling errors can be incorporated into the design of the command signals. Techniques are presented that facilitate implementation and indicate prudent choices for the amount of fuel to be used. The method is compared to other command generation techniques that balance fuel usage and slew time. to 128.205.23.23. Redistribution subject to ASME license or copyright; see http://www.asme.org/terms/Terms_Use.cfm ' The state space matrices A and B represent the system augmented with the fuel usage variable; A" and Bo represent the dynamics of the original system.
A method for generating on-off command profiles for flexible systems is presented. The command pr... more A method for generating on-off command profiles for flexible systems is presented. The command profiles move a system without residual vibration while using a specified amount of actuator fuel. Robustness to modeling errors can be incorporated into the design of the command signals. Techniques are presented which facilitate implementation and indicate prudent choices for the amount of fuel to be used. The method is compared to other command generation techniques that balance fuel usage and slew time.
Vibration absorbers appear in a wide range of uses including, but not limited to, architecture: s... more Vibration absorbers appear in a wide range of uses including, but not limited to, architecture: smoke stacks, windmills, bridges, and cellular towers; consumer goods: refrigerators, seating in vehicles, and dishwashers; and in rotational equipment: pumps, generators, and engines . However, the application to the field of robotics, automated manufacturing, and known trajectories has been limited.
The precise control of spacecraft with flexible appendages, such as solar panels or antennas, is ... more The precise control of spacecraft with flexible appendages, such as solar panels or antennas, is extremely difficult. The complexity of this task is magnified many times when several of these spacecraft must be controlled in unison as in formation flying. Formation flying (FF) requires that individual spacecraft in the group maintain relative position and velocities with respect to each other. One of the difficulties with formation flying is that the satellites must be autonomous and able to generate and correct their own orbit and attitude profiles without continual guidance from the ground. The objective of the current work is to enhance the existing formation flying technologies by integrating input shaping techniques to reduce vibration in flexible appendages. Specifically, input shaping will be used with a virtual structure PD formation flying control algorithm to control motion
ABSTRACT Boom cranes are used for numerous material-handling and manufacturing processes in facto... more ABSTRACT Boom cranes are used for numerous material-handling and manufacturing processes in factories, shipyards, and construction sites. All cranes lift their payloads by hoisting them up using overhead suspension cables. Boom cranes move payloads by slewing their base about a vertical axis, luffing their boom in and out from the base, and changing the length of the suspension cable. These motions induce payload oscillation. The problem of payload oscillation becomes more challenging when the payload exhibits double-pendulum dynamics that produce two varying frequencies of oscillation. This paper studies the swing dynamics of such cranes. It also applies input shaping to reduce the two-mode oscillatory dynamics. Experiments confirm several of the interesting dynamic effects. [DOI: 10.1115/1.4005933]
ABSTRACT Helicopters are often used to transport supplies and equipment to hard-to-reach areas. W... more ABSTRACT Helicopters are often used to transport supplies and equipment to hard-to-reach areas. When a load is carried via suspension cables below a helicopter, the load oscillates in response to helicopter motion and external disturbances, such as wind. This oscillation is dangerous and adversely affects control of the helicopter, especially when carrying heavy loads. To provide better control over the helicopter, one approach is to suppress the load swing dynamics using a command-filtering method called input shaping. This approach does not require real-time measurement or estimation of the load states. A simple model of a helicopter carrying a suspended load is developed and experimentally verified on a micro coaxial radio-controlled helicopter. In addition, the effectiveness of input shaping at eliminating suspended load oscillation is demonstrated on the helicopter. The proposed model may assist with the design of input-shaping controllers for a wide array of helicopters carrying suspended loads.
Methods for rapidly computing command signals that can move a flexible system without residual vi... more Methods for rapidly computing command signals that can move a flexible system without residual vibration and also limit the transient deflection have recently been introduced. These types of commands utilize a simple model and their performance is sensitive to both the accuracy of the system model and the desired move distance. Robust analytic deflection-limiting commands are described and evaluated in this paper. On average, the new formulation produces commands that are nine times more robust than the previous formulation. Traditional methods for measuring robustness fail to capture all the important features of these rest-to-rest commands. However, their results compare favorably to performance measures designed specifically for deflectionlimited commands. Simulation results on a mass-spring-mass system are used to demonstrate the key advancements.
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Papers by William Singhose