Drive-by-wire is becoming a new technology in automobile replacing the current mechanically linked systems with electronic ones. Lately, it has attracted considerable attention, because of considerable advantages incl...
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Drive-by-wire is becoming a new technology in automobile replacing the current mechanically linked systems with electronic ones. Lately, it has attracted considerable attention, because of considerable advantages including safety, cost reduction, flexible interior design, reducing the weight and etc. With the ‘by-wire’ system, drivers could use different types of control devices in shape and function for the existing steering wheel and pedals, or even drive by one control device integrating the brake pedal, accelerator pedal and other functions. In this paper, a new drive-by-wire system is built by using the Electric Power Steering (EPS), Accelerator Pedal Module (APM) and a simple actuating mechanism for brake pedal. Especially, we concentrate on steer-by-wire system. To improve the accuracy and safety in steering, a new type of integrated reactive joystick and control algorithm is developed. The new joystick has larger displacement than general commercial joysticks and can generate the reactive force which promotes safe driving by preventing too fast steering. The new control scheme is one of the bilateral controls that stands on the base of the teleoperation control. Therefore, drivers could get more information about the status of car. The experiment is performed by a field test using a real car and shows the performance of this steer-by-wire system with control algorithm.
The concept of C-space entropy as a measure of knowledge of C-space for sensor-based path planning and exploration for general robot-sensor systems was introduced in Yu, Y. and Gupta, K. (2000). The robot plans the ne...
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The concept of C-space entropy as a measure of knowledge of C-space for sensor-based path planning and exploration for general robot-sensor systems was introduced in Yu, Y. and Gupta, K. (2000). The robot plans the next sensing action to maximally reduce the expected C-space entropy, also called the maximal expected entropy reduction, or MER criterion. The expected C-space entropy computation, however, made an idealized assumption. The sensor was assumed to measure exact data, i.e., it was not subject to noise. In this paper we extend this approach by using a real noisy sensor model. Sensing actions can then be compared on the basis of their uncertainty models. This offers the ability for using more than one principle sensor (multisensory exploration), because sensor readings can be weighted by evaluating the expected measurement quality. Additionally, it makes robot motion planning viable for tasks such as object surface inspection, which require the robot to come very close to the obstacles to achieve high sensing accuracy.
Since teleoperation systems are mostly executed in the extreme environment, there are constraints in designing the mechanism and choosing sensors. This paper presents a novel quantitative comparison method of teleoper...
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Since teleoperation systems are mostly executed in the extreme environment, there are constraints in designing the mechanism and choosing sensors. This paper presents a novel quantitative comparison method of teleoperators based on H/sub /spl infin// framework. The upper H/sub /spl infin// norm bound of the system including H/sub /spl infin// sub optimal controller is used as the performance index. As a case study, the method is applied to a real teleoperation system to study the effects of sensory configuration and back-drivability of the mechanism on the performance of the system in tasks, which involve different environment impedances. It can be important criteria to design a teleoperator from the control point of view.
The paper addresses the problem of autonomous underwater vehicle (AUV) modeling and parameter estimation as a means to predict the expected dynamic performance of underwater vehicles and thus provide solid guidelines ...
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The paper addresses the problem of autonomous underwater vehicle (AUV) modeling and parameter estimation as a means to predict the expected dynamic performance of underwater vehicles and thus provide solid guidelines during their design phase. The use of analytical and semi-empirical (ASE) methods to predict the hydrodynamic derivatives of a large class of AUVs with conventional, streamlined bodies is discussed. An application is made to the estimation of the hydrodynamic derivatives of the MAYA AUV, an autonomous vehicle that is being developed under a joint Indian-Portuguese project. The estimates are used to predict the behavior of the vehicle in the vertical plane and to assess the impact of stern plane size on its expected performance.
This paper deals with the design of complex dynamic model of quadruped walking mobil robot. There is described the method of building of the numerical computational model and its simulating. Complex model consist of s...
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This paper deals with the design of complex dynamic model of quadruped walking mobil robot. There is described the method of building of the numerical computational model and its simulating. Complex model consist of submodels of robotic mechanism, DC motor, gearbox model and thermal model of electrical motor. Control algorithms are also considered in model. In the paper is also discussed application of computational model directly for control of robot and also as a data generator for global and local approximation method, mainly artificial neural networks.
This project is concerned with computational simulation of air flow in the individual parts of a synchronous machine. FLUENT6 software was used for computational modeling. A model of a machine fan was built, which was...
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This project is concerned with computational simulation of air flow in the individual parts of a synchronous machine. FLUENT6 software was used for computational modeling. A model of a machine fan was built, which was used for calculation of ventilation characteristics. Ventilation characteristics were calculated for three ventilator diameters. The aim was to find the operating point for each fan. A model of the asymmetrical inlet to the machine and the distribution of airflow to the stator and rotor was built, which consisted of inlet to machine, axial stator and rotor channels and ten radial channels in the stator packet. A parametric computational model was developed with three main parameters - size of axial stator and rotor channels and size of radial channels. The results of the computer simulation were compared with experimental measurements, which were accomplished on the synchronous generator using a Pitot tube and digital micro manometer.
The atomic force microscope (AFM) system has evolved into a useful tool for direct measurements of intermolecular forces with atomic-resolution characterization that can be employed in a broad spectrum of applications...
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The atomic force microscope (AFM) system has evolved into a useful tool for direct measurements of intermolecular forces with atomic-resolution characterization that can be employed in a broad spectrum of applications such as electronics, semi-conductors, materials, manufacturing, polymers, biological analysis, and biomaterials. The non-contact AFM offers unique advantages over other contemporary scanning probe techniques such as contact AFM and scanning tunneling microscopy. Current AFM imaging techniques are often based on a lumped-parameters model and ordinary differential equation (ODE) representation of the micro-cantilevers coupled with an ad-hoc method for atomic interaction force estimation (especially in non-contact mode). Since the magnitude of the interaction force lies within the range of nano-Newtons to pica-Newtons, precise estimation of the atomic force is crucial for accurate topographical imaging. In contrast to the previously utilized lumped modeling methods, this paper aims at improving current AFM measurement technique through developing a general distributed-parameters base modeling approach that reveals greater insight into the fundamental characteristics of the microcantilever-sample interaction. For this, the governing equations of motion are derived in the global coordinates via the Hamilton's Extended Principle. By properly selecting a set of general coordinates, the resulting non-homogenous boundary value problem is then converted to a homogenous one, and hence, analytically solvable. The AFM controller can then be designed based on the original infinite dimensional distributed-parameters system which, in turn, removes some of the disadvantages associated with the truncated-model base controllers such as control spillovers, residual oscillations and increased order of the control. Numerical simulations are provided to support these claims.
A translational cantilevered Euler-Bernoulli beam with tip mass dynamics at its free end is used to study the effect of several damping mechanisms on the stabilization of the beam displacement. Specifically, a Lyapuno...
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A translational cantilevered Euler-Bernoulli beam with tip mass dynamics at its free end is used to study the effect of several damping mechanisms on the stabilization of the beam displacement. Specifically, a Lyapunov-based controller utilizing a partial differential equation model of the translational beam is developed to exponentially stabilize the beam displacement while the beam support is regulated to a desired set-point position. Depending on the composition of the tip mass dynamics assumption (i.e. body-mass, point-mass, or massless), it is shown that proper combination of different damping mechanisms (i.e., strain-rate, structural, or viscous damping) guarantees exponential stability of the beam displacement. This novel Lyapunov-based approach, which is based on the energy dissipation mechanism in the beam, brings new dimensions to the stabilization problem of translational beams with tip mass dynamics. The stability analysis utilizes relatively simple mathematical tools to illustrate the exponential and asymptotic stability results. The numerical results are presented to show the effectiveness of the controller.
A switch-shunt stiffness method for vibration attenuation of flexible beams undergoing translational base motion with a laminated piezoelectric patch attachment is presented. The piezoelectric actuator, bonded on the ...
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A switch-shunt stiffness method for vibration attenuation of flexible beams undergoing translational base motion with a laminated piezoelectric patch attachment is presented. The piezoelectric actuator, bonded on the top surface of the flexible beam, is switched between open and short circuit configurations. This results in a variable equivalent stiffness which, in turn, can remove energy from the overall system by directly affecting the stored potential energy in the flexible beam. Initially, a single degree of freedom system is considered for validation of the switched stiffness method. The method is then applied to a flexible beam with moving base, representing a Cartesian-type one-link robot manipulator. Simulation results demonstrate favorable vibration attenuation in both cases;the single degree of freedom oscillator and the cantilever flexible beam. Several variations of the switching mechanisms are explored in an effort to achieve optimal vibration characteristics. Experimental testing is currently under investigation for validation of the simulation results presented here.
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