Piotr Ociepka

Motion Analysis of Mechatronic Equipment Considering the Example of the Stewart Platform

Modern CAD/CAE allows supporting the process of design and construction at many stages, from concept development through specific engineering calculations to the creation of design documentation. In the case of constructing mechanisms, the kinematic and dynamic analysis of the proposed system is an important step in the introduced process. The paper presents an example of the kinematic and dynamic analysis of the Stewart platform using Siemens NX software [1, 2]. The conducted investigation has allowed determining the geometric characteristics of the mechanism of the Stewart platform as well as the geometric parameters of actuators and their location. A dynamic analysis of the platform helped with establishing the required motor forces for realizing the moves with the maximum speed and acceleration. This allowed the initial selection of the parameters of electric motors. Traffic analysis was also performed for investigating collisions between the parts of the hexapod and between the hexapod and its environment.

Simulation of the Stewart Platform Carried out Using the Siemens NX and NI LabVIEW Programs

The paper presents the implementations of the control algorithm of a virtual system (Stewart platform) in the CAD/CAE system (Siemens NX) and in the NI LabVIEW supervisory and control system. The combination of both systems enables the virtual simulation and presentation of the results in relation to the chosen in the work virtual model of the Stewart platform. The virtual model of the Stewart platform with the imposed constraints and mobility limitations was built in the Siemens NX CAD/CAE system. Each of the modeled elements is based on the real components of the car simulator prepared for the persons with mobility impairments. The chosen model of a Stewart platform is a system with six degrees of freedom that is often used to build various types of simulators (e.g. flight, car). Using the NI LabVIEW software, a mathematical model of the Stewart platform was built and inverse kinematics task was implemented in relation to the model of the platform. The created mathematical model that describes the behavior of the Stewart platform was used to determine the inputs to the control system of platform actuators.

Geometric Analysis of Motions Exercised by the Stewart Platform

The study outlines the geometric analysis of motions executed by the Stewart platform and operated in the environment of a simulator for driving learning to be used by disabled people. The analysis was carried out on the basis of results obtained from the resolved kinematic problem for the inversed platform.

Mapping of the Characteristics of a Drive Functioning in the System of CAD Class Using the Integration of a Virtual Controller with a Virtual Model of a Drive

The paper presents the method of mapping functioning of a 3D model of reciprocating motion drives of a robotic system, which is the final stage of a works transport system, created in the Siemens PLM NX 8.5 CAD/CAE environment. For this purpose, the 3D model of the considered robotized system, prepared for motion simulation in the “Motion Simulation” module of the Siemens NX system. In the elaborated model was defined the suitable components of the system and the joints between them. These components and joints were defined in such a way as it is possible to map functioning of a real drive in a virtual environment. The basis of functioning of such created drive model is information transmitted from a virtual controller basing on the DDE (Dynamic Data Exchange) standard of data exchange. In the adopted communication method between the CAD system and the virtual PLC controller is required to transfer displacement values at individual nodes in such a way as to map functioning of the real system. Therefore in the control program of a virtual controller is stored functioning characteristic of the considered drives system of the reciprocating motion. As the result of conducted work the virtual 3D model, prepared in a system of the CAD/CAE class, was integrated with the virtual controller, taking into account the mapping of functioning characteristic of drives.

The Simulator for Teaching how to Drive a Car for People with Disabilities

This work presents ideas for a passenger car driving simulator for teaching the disabled. The functional structure, design assumptions, and the concept and operation of the proposed simulator are presented.

Analysis of the Dynamic Properties of the Mechatronic Integrator of Control Procedures of the Vehicle Driven by Persons with Disabilities

The simulator of behavior of a disabled person driving the car is especially useful equipment. Mainly, the hands and the face of a driver are observed in order to determine facial expressions, slow-motion of the head and eyes, which according to the description of the simulation indicate disturbances of concentration and, in extreme cases may lead to nausea, or even loss of consciousness [1]. So, in the realization phase of the configuration the control system, the need to maintain high standards of safety was taken into consideration. The main problem described in the paper was measuring the acceleration and frequency of vibration during the operation of the simulator [2, 3, 4]. This analysis will help to determine whether any particular circumstances during crash simulations do not exceed the acceleration limit while the driver still feels its effects. It is also important to examine the frequency of vibrations, which during long driving simulator can cause nausea, dizziness or loss of consciousness. This analysis is a part of widely applied CAx analysis performed using special computer platforms that should be properly organized [5] and helps to expand the range of investigations [6].

Examination of a Cargo Space of a Freight Wagon Modified with Composite Panels

This article presents the method of solving the problem considered with the too fast wearing of a steel sheet paneling of a freight wagon body. The method, described in the work, bases on the use of additional components, which are made of composite materials. The proposed solution is based on the appropriate lining of the inside of a wagon body with composite panels. In order to verify the placing and fixing of composite panels to wagon walls, as well as to verify the behavior of joined composite panels in the given conditions of a wagon work it was used a computer analysis basing on the finite element method. Because of the scale of the analyzed problem it was also created a virtual model of the research stand, which allows experimentally verifying phenomena occurring between the joined composite panels mounted on walls of a freight wagon that is made in a natural size. Carried out researches allowed determining the method of arrangement the composite panels in the inside space of a freight wagon body. It was also determined the method of panels joining and the method of their fixing to the steel paneling of a wagon body. It was also determined the procedure of transferring the results of the experimental analysis of the wagon walls, made in a natural size, on a real object using the matching of a virtual model.

Designing Mechatronics Equipment Based on the Example of the Stewart Platform

Designing specific technical equipment requires solving a number of problems that consider the theoretical structures of particular technical means. In the case of mechatronics equipment, one should take into consideration three groups of problems: designing mechanical components, designing actuators and designing a control program [1]. Moreover, it is important to properly organize the process for the purpose to obtain a coherent project linking the three above mentioned sub-systems of mechatronics equipment [2]. Only when three sub-systems are properly designed, the whole system can appropriately and effectively operate. One should mention that the design process could be analyzed not only from the perspective of the partition of the main system but also from the perspective of design, material and assembly features [1, 3].Taking into account constraints providing for the design process, the procedures of creating the Stewart platform were followed. This platform was devised as an actuator of a car simulator [4, 5, 6, 7]. The process of designing was divided into the before introduced phases. First, the system of actuators was elaborated referring to information about the velocity and acceleration of a real car. Second, the control system was elaborated. The system was matched to the mechanical system of actuators. At the third stage, the control program was elaborated and tuned.All presented stages of the design process were computer aided so that the process of designing was conducted in virtual reality. It results in shortening the durability of the designing phase and in decreasing costs. This preparatory phase, including the realization phase, allowed preparing the real car simulator.

Application of the Method Based on Knowledge and Experience for Adding the Cutting Tools and Parameters Selection

The paper presents the method basing on engineering knowledge and experience for adding selection of cutting tools and parameters in a turning process. In this method, the system is built basing on a hybrid architecture that combines an advisory system and the CBR (Case Based Reasoning) method. It is presented the structure of the advisory system, and the functioning of the CBR method. Attention has been paid to the problem of an “empty database” in relation to systems basing on the CBR method. The paper also presents the possibility of integrating the developed method with a CAM system.

Application of Programs of the CAD/CAE Class for Creating the Virtual Laboratory Stand

The article presents the stages of creating a virtual laboratory stand for performing the cycle of tests of the system response to dynamic excitation. To create the virtual laboratory stand was used the PLM Siemens NX 8.5 software. It was shown the method of realization the dynamic analysis in the Motion Simulation module, which result was the characteristic (form) of the system excitation. Then, on the virtual laboratory stand, was conducted the analysis of vibration of the investigated system realized in the Advanced Simulation module. For calculations was used the “Response Simulation” solver, which allows analyzing the system responses to dynamic excitations. Next the results were compared with vibrations measurements made on the real laboratory stand. This lets to verify and adjust the created FEM model.