R. Grepl

Real-Time Control Prototyping in MATLAB/Simulink: Review of tools for research and education in mechatronics

The simulation modeling and the control of real plant are two-very often separated-fields of mechatronic practice, research and education. The deep gap between simulation world of controlled system and practical implementation in e.g. embedded hardware can be bridged through the use of special hardware and software directly in MATLAB/Simulink environment. This paper presents the review of available tools with respect to their usability, sampling rate capability, the necessary software needs and also the financial requirements. Most of approaches require the C code generation using Real-Time Workshop. However e.g. the Real-Time Toolbox works directly with normal mode of Simulink which can be especially recommended for the educational applications. The paper briefly describes several case studies where undergraduate students can deal with real educational models without previous knowledge of the real-time systems. The list of available hardware and software tools is not complete but includes all important approaches: low cost general purpose I/O card with/without C code generation, high-performance hardware for comfort rapid prototyping or hardware-in-the-loop simulation and code generation for embedded targets (16 or 32bit microcontrollers or DSP).

Development of 4WS/4WD Experimental Vehicle: platform for research and education in mechatronics

This paper presents the development of scaled four-wheel steering and driven (4WS/4WD) vehicle ideally suited as a research and educational platform in mechatronics. Basic kinematic and dynamic models are presented as the base for vehicle computer simulation as well as for the parameter estimation using variants of Kalman filter. Further the structure of control and power electronic system is briefly described. Next, several examples of practical results dealing with parameter and state estimation are presented as a demonstration of the use of platform in education and research. The main contribution of the platform presented here is: the demonstration of wide range of problems including kinematics, embedded control and system identification; the high level of integration and complexity of solution which is typical for mechatronics; and the close relation to automotive engineering which is substantial in mechatronics but which also features the high level of attraction and motivation for students.

Control unit architecture for biped robot

This paper deals with the design of a control unit for biped robot „Golem 2“ with 12 DOF. It contains information about the topology of electronic system, including description of communication between MC units, sensing elements and PC. The kinematic models used for drive robot and the information about their importance for static walking are mentioned. Some information about actuators (Hitec servos) and specificity their control are also described.

Extended kinematics for control of quadruped robot

This paper deals with the extended kinematical model for quadruped mobile walking robot. The model has been built based on homogenous coordinates approach. The robot is comprehended as an open tree manipulator and therefore standard algorithms for forward and inverse kinematics can be employed. However, the inverse model named 12–18 works with the redundant manipulator structure and pseudoiverse of Jacobian matrix should be used. The inverse model 3–3 uses regular manipulator and allows separate positioning of each leg. After processing and simplification of the equations in Maple, the algorithms have been implemented in Matlab environment. The model automatically built in SimMechanics has been used for verification. Finally, the results have been tested using VRML visualization.

Simulation modeling, optimalization and stabilisation of biped robot

This paper deals with proposal of humanoid robot construction. The construction of two legs (six DOF each) is described. Computational modelling was used, particularly forward and inverse kinematic model. By help of these models was produce several functions for the control of moving robot’s body. Coordination of robot move was simulated in environment VRML.

Control of Stator Winding Slot Cooling by Water Using Prediction of Heating

This project is concerned with non-convectional direct stator winding slot cooling using water. The aim is to find optimal algorithm for control of water cooling. The control algorithms are tested on the experimental device, which is part of real synchronous machine with permanent magnets. The thermal model was built as a base for pump control algorithm model of a machine without thermal sensors. The Thermal model is possible used as predictor of machine heating in real time. This type of water cooling shows better effect on the machine heating than common water cooling system on the cover.

Selection of MEMS Accelerometers for Tilt Measurements

In order to build a tilt sensor having a desired sensitivity and measuring range, one should select an appropriate type, orientation, and initial position of an accelerometer. Various cases of tilt measurements are considered: determining exclusively pitch, axial tilt, or both pitch and roll, where Cartesian components of the gravity acceleration are measured by means of low-g uni-, bi-, tri-, or multiaxial micromachined accelerometers. 15 different orientations of such accelerometers are distinguished (each illustrated with respective graphics) and related to the relevant mathematical formulas. Results of the performed experimental study revealed inherent misalignments of the sensitive axes of micromachined accelerometers as large as 1°. Some of the proposed orientations make it possible to avoid a necessity of using the most misaligned pairs of the sensitive axes; some increase the accuracy of tilt measurements by activating all the sensitive axes or reducing the effects of anisotropic properties of micromachined triaxial accelerometers; other orientations make it possible to reduce a necessary number of the sensitive axes at full measurement range. An increase of accuracy while using multiaxial accelerometers is discussed. Practical guidelines for an optimal selection of a particular micromachined accelerometer for a specific case of tilt measurement are provided.

Adaptive composite control of electronic throttle using local learning method

This paper deals with an application of receptive field weighted regression (RFWR) method for the composite control of automotive electromechanical throttle. Simulation experiments use the plant model optimized for hardware-in-the-loop simulation and tuned according to experimental results. Composite controller consists of PID and feedforward inverse dynamics implemented using RFWR. Because of significant dry friction in the system, two independent RFWR approximators are used to solve the problem of discontinuity at zero velocity. Satisfactory simulation results are presented.

Fault tolerant BLDC motor control for hall sensors failure

In most brushless direct current (BLDC) motor drives, there are three hall sensors as a position reference. This paper presents a method that allows the operation of a BLDC motor with one faulty hall sensor. The situations considered are when the output from a hall sensor stays continuously at low or high levels, or a short-time pulse appears on a hall sensor signal. For fault detection, identification of a faulty signal and generating a substitute signal, this method only needs the information from the hall sensors. So this method can be added as a standalone subsystem to existing drives. The paper provides many simulations on how the presented method reacts for various types of faults. An experimental evaluation is provided too. Due to the demand to operate at a high speed, the method is implemented into the FPGA.

Composite Controller for Electronic Automotive Throttle with Self-tuning Friction Compensator

The automotive throttle is a highly nonlinear servo system with significant parameter changes caused by temperature, wear and lubrication during the vehicle operation. This paper describes the controller structure with basic heuristically tuned (fixed) PID controller coupled with tuned model-based feedforward spring and feedback error-based friction compensator. The extended Kalman filter with augmented state vector is used for parameter and state estimation based on nonlinear model and noisy position measurement. Simulation results of controller behavior and friction estimation are presented.