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EPS (electric power-assisted steering) system has been used to replace traditional hydronic power steering system in vehicles. In an EPS system, the assisting torque is from an electric motor for steering effort. The performance of an EPS system requires that the high frequency external disturbance in road reaction torque be attenuated so that the driver could feel comfortable - light and less vibration...
Real-time controllers have traditionally used computer hardware systems that require expertise in hardware knowledge before the controller can be effectively implemented. This paper introduces a single-processor PC-based real-time motion controller developed using QNX 6.0 Neutrino operating system. Using the advantages of a distributed software system and an object-oriented architecture, the developed...
PID control schemes still continue to be widely used for most industrial control systems. This is mainly because PID controllers have simple control structures, and are simple to maintain and tune. However, it is difficult to find a set of suitable control parameters in the case of time-varying and/or nonlinear systems. For such a problem, the robust controller has been proposed. Although it is important...
In this paper, we discuss the design of multivariable motion controllers exploiting crosscouplings in the controller for open loop decoupling, disturbance rejection and feedforward decoupling. Using specific properties of motion systems, we illustrate that frequency response design methods can be extended to handle several multivariable control problems. Application to high performance motion systems...
This paper presents the development of an experimental testbed for multiple vehicles formation control. This four 3-DOF helicopter-testbed in the Flight Systems and Control (FSC) Laboratory of University of Toronto can be applied to validate the effectiveness of formation flight and cooperative (coordination) control strategy. Each helicopter has three degrees of freedom, in elevation, pitch and travel...
This paper presents recent research results for feedback control design of motion systems. Two model-free approaches are investigated, that exploit the ease of experimentation which is typical for motion systems. One approach is data-based design of a linear feedback controller which realizes desired closed-loop sensitivity and complementary sensitivity transfer functions. These transfer functions...
The objective of this paper is development of a formation control and station keeping control law for a constellation of satellites in a circular orbit. It is shown that by utilizing feedback linearization or nonlinear compensation technique an efficient nonlinear control design strategy may be implemented that leads to solutions valid for larger set point regulation and station keeping problems....
In this paper a passivity-based dynamic visual feedback control system, based on extended task space formulation, is addressed to control the kinematically redundant manipulator. Specifically, we consider the target tracking problem of dynamic visual feedback systems in the 3D-workspace. Firstly the brief summary of the visual feedback system is given with the fundamental representation of a relative...
This paper presents a smooth sliding mode control approach for the motion control of a Stewart platform. The control scheme is proposed given that the overall system parameters are subject to uncertainties while only the positions and velocities of links are measurable. To achieve high performance tracking control of a 6 DOF Stewart platform normally requires the full knowledge of the system dynamics...
In this paper, an adaptive control scheme is developed for an n-DOF nonlinear time-variant teleoperation system with large time delays in the communication channels. To make the stability of the overall system be independent of the communication delay, two nonlinear adaptive motion/force controllers are bilaterally designed for both master and slave manipulators. A compliant force feedback loop is...
This paper presents an efficient control scheme for compliant motion control of kinematically redundant manipulators and its evaluation using an experimental 7 degrees-of-freedom manipulator, REDIESTRO (a Redundant Dextrous Isotropically Enhanced, Seven Turning-pair RObot). A transpose Jacobian based hybrid impedance control (TJ-HIC) scheme is proposed that provides a unified approach for combining...
Intended for being used in legged robots, a specially designed nonlinear actuator, dual smart drive, which offers continuously changing transmission ratio and dual properties, and that is very suitable for situations where the same drive is required to perform two different types of start-stop motions of the mobile link, is introduced. Then, the associated control problem to this nonlinear actuator...
In this paper, an adaptive motion/force controller is developed for bilateral teleoperation systems. Design of an output feedback model reference adaptive controller (MRAC) at the remote site improves the position/velocity response with stability guarantee and a similar controller at the master site enhances the force tracking as the transmission time delay varies
The path following problem for a simplified model of an unhabited aerial vehicle (UAV) in longitudinal motion is investigated using a piecewise-affine (PWA) control law and a Lyapunov based controller design technique. The search for the parameters corresponding to the controller and to a piecewise quadratic Lyapunov function is formulated as an optimization problem subject to linear and bilinear...
In this paper we build on previous work by the authors on spacecraft formation motion design for fuel-image optimality by Hussein, Scheeres and Hyland (2005). Previous results indicate a tradeoff between image quality and fuel expenditure by I. I. Hussein et al. (2005). In this paper we state results relating image quality to the trajectory of a sparse system of TV telescopes. This relationship is...
We present a state-feedback control of a two-link flexible-joint robot. We use three-layer neural networks to learn the unknown parts of the desired control laws. Therefore, the control algorithm does not require the mathematical model representing the robot. The neural networks' weights are adapted on-line. Therefore, the control system can adapt to changes during operation such as payload changes...
The problem of designing a robust dynamical controller for solving the tracking control problem for a flexible-link manipulator is studied. The design methodology is based on construction of a two-time scale dynamical motion of the closed-loop system. It is shown that for a sufficiently small perturbation parameter associated with the dynamical controller consisting of high order derivatives of the...
This paper presents a unified control-oriented modeling of a free-flying space robot interacting with a target satellite. The purpose of the modeling is to design a controller to track motion trajectory while regulating the force interaction between the space robot and the target satellite. Many space missions can benefit from such a modeling system, for example, autonomous docking of satellites,...
The satisfaction of constraints between the foot and the ground during balancing of bipedal standing is important. In this work, the effects of two constraints, namely the gravity constraint and the friction constraint, on balancing of a simplified two-dimensional biped are considered. The bounds imposed on the control torque are first determined analytically. Such results not only show the specific...
A robotic excavator must be able to operate in all three states of manipulator motion: free-space, contact and exertion of a force against an environment. A position accommodation control scheme is ideally suited for this task. The position accommodation method described in this study uses a position controller to track a pre-defined trajectory in the absence of a force at the excavator bucket. If...
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