Krzysztof Nowopolski

Neural Speed Controller Trained Online by Means of Modified RPROP Algorithm

In this paper, the synthesis and the properties of the neural speed controller trained online are presented. The structure of the controller and the training algorithm are described. The resilient backpropagation (RPROP) algorithm was chosen for the training process of the artificial neural network (ANN). The algorithm was modified in order to improve controller operation. The specific properties of the controller, i.e., adaptation and auto-tuning, are illustrated by the results of both simulation and experimental research. An electric drive with permanent magnet synchronous motor (PMSM) was chosen for experimental research, due to its impressive dynamics. The obtained results indicate that the presented controller may be implemented in industrial applications.

Identification of multi-mass mechanical systems in electrical drives

This paper presents methods for parameter identification of mechanical resonance of two-mass and multi-mass electrical drive system. The presented methods were applied in the field of parameter identification. Various identification setups are considered: different identification models (ARX and OE), sampling periods and models orders. Results for two different excitation signals are presented: pseudo random binary signal and chirp wave. Spectral analysis is used to calculate frequency response data of electric drive with elastic connection. The discussed methods of identification are verified by both simulation and laboratory stand test.

Static and dynamic ergonomic corrects of torque controlled in bicycle ergometer

In this paper various methods of ergonomics improvement in electric bicycle pedaling are discussed. The main goal is to control an average amperage of generator powered by a cyclist, but considering the unsteadiness of human legs torque vs. angular position of the support. In the paper, four different approaches for generating the current reference trajectory are compared - two of them use only position signal, and the next two use also velocity signal in the ergonomic improvements calculations.

Two Approaches to Speed Control for Multi-Mass System With Variable Mechanical Parameters

This paper is dedicated to the motion control system of a multimass mechanism with occurring resonances and variable moment of inertia. The proposed concept of control structure for such mechanism consists of a filter damping higher resonance frequencies and an adaptive speed controller. The filter has properly selected fixed characteristics giving a compromised filtering effect in a range of resonance frequency variation, caused by the variable moment of inertia. The used neural adaptive controller realizes active damping of lower resonance frequencies, which are not eliminated by the resonance filter. This original concept is compared with a more complex solution, treated as a reference, which contains an offline-tuned resonance filter together with an offline-adjusted PI-two degrees of freedom controller. Good speed control dynamic properties of the proposed concept in comparison with the reference complex solution are proven by laboratory results.

Speed calculation methods in electrical drive with non-ideal position sensor

In this paper three methods of electric motor angular speed calculation are compared. The source of the measurement signal is a 14-bit absolute encoder. The authors compared the well-known classic methods M with more advanced approaches. First of the complex methods is based on utilization of phase loop lock system in an estimation process using on-line system model. The third method discussed in the paper is focused on application of Chebyshev filter. Short description of all of the mentioned method is followed by simulation and experimental results. The results are presented on an instance of permanent magnet synchronous motor drive, with both speed controller and speed calculation algorithms implemented in a digital signal processor system.

Control of electromechanical object with backlash and elasticity within interconnection between motor and load

In this paper, an analysis of various control structures for two-mass drive system with backlash are presented. Theoretical model of this complex mechanical system is derived and presented. Conventional PI speed controller is compared with 2DOF-PID controller considering delays in control path and location of resonances, PID controller with additional feedback signals and fuzzy PD-I controller. The comparison of the control process and its dynamics is based on integral and time-domain quality factors.

Experimental analysis of selected control algorithms of electromechanical object with backlash and elastic joint

The paper presents laboratory tests of two selected structures of speed controller utilized in two mass system with elastic joint and backlash between motor and load. Theoretical model of the mechanical system has been derived and tested by simulation in previously published research. The aim of the article is to compare the best structure obtained by simulation with the conventional PI controller, treated as a reference. The PI speed controller was tuned according to symmetry criterion and the 2DOF-PID controller was tuned according to other method known from literature, delays in control path and location of resonances were considered. Comparison of control process was carried out on the basis of quality indicators.

PMSM laboratory stand for investigations on advanced structures of electrical drive control

This paper presents design, structure and experimental tests of a laboratory stand for the investigation on advanced control algorithms for electrical drive. The main propulsion unit is a permanent magnet synchronous motor, which is connected with a brushless DC motor operating as a dynamically adjustable load. System is controlled by a DSP with the dedicated speed and position measurement extension boards. Availability of an external DSP bus allowed to incorporate FPGA system to the control layer. The paper describes also an innovative, object-oriented approach to the implementation of the control algorithms in DSP system.

Application of adaptive neural controller for drive with elastic shaft and variable moment of inertia

In the paper an application of adaptive neural controller for electrical drive with elastic coupling between motor and the driven mechanism with variable moment of inertia is presented. Due to presence of several mechanical resonances (since it is a multi-mass system) at higher frequencies, a suitably tuned speed filter is applied to the feedback loop in order to damp the selected resonance frequencies. This approach allows to improve the control properties. The speed controller is designed as a neural controller, which allows to remain properties of the control process irrespective of the variable moment of inertia. The collected results of simulation and experiment confirm the proper operation of the control system.

Gearless Pedaling Electric Driven Tricycle

In the paper the general conception and real construction of a three-wheel bicycle with auxiliary electric propulsion is presented. Each of the vehicle wheels is driven by an electric motor (BLDC) controlled by the central system of power distribution. The generator that charges a battery pack is driven by pedals. The vehicle speed is proportional with adjustable ratio to the pedaling velocity, whereas the power delivered to the motors is appropriately increased to the pedaling power with adjustable degree. Description and analysis of the selected modules of the vehicle are documented with prototype research results.