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Modeling errors are one of the elements responsible for deficiencies in sensorless collision detection of robotic systems. By providing a specific formulation of manipulator equations, this paper presents a time-variant threshold for observer residues in joint space of a manipulator in order to provide more accurate collision detection ability compared to constant thresholds. The time-variant threshold...
Motion control usually includes the precise control of position/velocity and acceleration control while accurate acceleration control is not useful in many applications. Traditional position/velocity control is derived by feedback based, PID controllers. However the disturbance observer further increases the stability and robustness of the controller. In this paper we assess the effectiveness of the...
This paper is concerned with speed tracking control problem for permanent-magnet synchronous drives (PMSM) in the presence of an variable load torque and unknown model parameters. The disturbance of speed control caused by inaccuracy of model parameters has been investigated. A load torque observer has been proposed to observe the load torque and estimate the disturbance caused by inaccuracy of model...
A model-based in-/out-flux detection scheme for managed pressure drilling is presented. We design a globally exponentially stable adaptive observer which estimates the unknown states and parameters of the hydraulic system and in particular quantifies the magnitude of the in-/out-flux and its location in the well. While the observer can be used purely as an in-/out-flux detection system, the paper...
In this paper an approach for observer based diagnosis for pneumatic systems in commercial vehicles is presented. Here leak detection and location in pipes is in focus. The approach is based on methods for leak monitoring of pipes in chemical industry which is extended to pneumatic systems. It uses a non-linear adaptive reference model of the pipe which is controlled and parameterized by a linear...
A study of the friction model for the leak detection with a nonlinear observer is presented. Classically the friction model in leak detection algorithms only relies on a constant parameter. In the present work, the use of a more elaborate friction model is considered, with a coefficient explicitly depending on the flow, either algebraically, or even differentially. Those friction formulations are...
The inverted pendulum contains non-negligible nonlinearities due to friction, causing limit cycles. In this paper, a recently proposed method is applied to estimate friction using only data from the closed loop operation. The estimate is compared with the results of open loop tests, showing their similarity. The friction compensation is carried out via two different approaches. First, Karnopp and...
The objective of Managed Pressure Drilling (MPD) is to enable precise control of the downhole pressure during drilling and completion operations. An essential part of an automated MPD control system is the downhole pressure estimator, usually referred to as the hydraulic model, which in most cases is the limiting factor for achievable accuracy of the system. In this paper we present a new design of...
Aims at the nonlinearity such as friction and varieties of system parameters and unmodeled dynamics in azimuth gun control system of tank, in order to improve the low speed performance and anti-interference ability, the strategy of LADRC is proposed. Considering nonlinearity and non-model dynamics as a composite disturbance, the math model of azimuth gun control system is established firstly, then...
In most servo motor drive applications, speed control is affected not only by disturbance torque but also by mechanical parameters such as inertia and friction coefficient. This paper presents a new technique for the inertia and friction identification which are based on adaptive identification. The strategy has been simulated and implemented in a drive system. The results demonstrate the high performance...
This paper discusses the problem of friction disturbance compensation of tank gun servo system. For the friction uncertainties and non-model dynamics in tank azimuth gun control system, the azimuth Gun Control system model and friction model are established firstly, then considering them as a composite disturbance, and then, extended states observer (ESO), a new observer is proposed to observe and...
This paper discusses the ADRC application in the photoelectrical platform for disturbance rejection. Firstly, model of stabilized platform system is established, in which uncertain external load disturbance and unmodelled dynamics are regarded as one integrated disturbance. Then, using ESO to observe and compensate this integrated disturbance, and using the compensation loop of active disturbance...
The contour accuracy of XY table directly driven by two linear motors was influenced by nonlinear friction of dynamic system. On the basis of analyzing the contour error of the system, the control strategy combining state observer and sliding-model controller with the cross coupling controller (CCC) was presented in the paper. A sliding-model state observer was proposed to estimate state z which was...
The load torque disturbance influences the performance of permanent magnet synchronous motor speed control. Therefore, to compensate this problem, this paper designed a model reference torque observer based on Popov-super-stability theory. This observer uses off-line calculation to obtain the model parameters and PI calculation of the speed model error to get the load torque. This structure is simple...
This paper presents a nonlinear adaptive observer to estimate the annular pressure profile throughout the well bore continuously while drilling. A simple mechanistic model is presented that captures the dominant phenomena of the drilling system and forms the basis for model-based observer and control design. A new nonlinear adaptive observer is developed for state estimation and parameter estimation...
This paper introduces a robust artificial neural network (ANN) based nonlinear speed observer for permanent magnet synchronous machines (PMSMs). A multilayer perception is trained online using back-propagation learning algorithm to estimate the rotor speed without any a priori dynamics knowledge. Thus, the proposed observer is able to cope with higher degrees of nonlinearity since it is not based...
This paper deals with an online identification of the Generalized Maxwell Slip (GMS) friction model for both presliding and sliding regime at the same time. This identification is based on robust adaptive observer without friction force measurement. To apply the observer, a new approach of calculating the filtered friction force from the measurable signals is introduced. Moreover, two approximations...
Friction stir welding (FSW) is a relatively new and promising joining process that is the subject of much current research. When welding with constant parameters, the axial force can vary significantly due to changes in workpiece temperature and other process variations. These variations produce welds with inconsistent microstructure and tensile strength. Control of the axial weld force is desirable...
Generally, friction/disturbance compensation is an important issue in high-precision motion control applications. In particular, when the system under control undergoes low-speed or reversal motions, the friction force and external disturbances will degrade motion accuracy. Therefore, to achieve satisfactory motion performance, it is necessary to simultaneously compensate for the friction force and...
This paper deals with the fault detection occurred in the mechanical position sensor of a mechatronic actuator Pierburg which is used in the BMW M57 diesel engine. This actuator is in charge of the control of the input air in the vehicle engine. Concretely, it is located between the throttle valve and the combustion chamber. It is supposed to ensure the control of air flow entering to the cylinder...
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