Mechatronic Structure Research Articles

Towards a Discrete Snake-Like Robot Based on SMA-Actuated Tristable Modules for Follow the Leader Control Strategy

Snake-like robots applications include surveillance and exploration of confined environments where human presence is incompatible. The attractiveness of this type of mechatronic structure is notably linked to the modular character and the hyper-redundancy of their architecture, which gives it both mechanical robustness and great manoeuvrability. However, due to the large number of degrees-of-freedom, the use of advanced mathematical models are needed to asses the motion patterns and to simulate it. A new snake-like robot architecture is introduced in this paper together with the development methodology of a replicable multistable module. The interest of this contribution lies in the combination of the mechanical stability of the modules with an easy-to-use direct kinematic model, thus avoiding the need of complex control strategies. The design of one module exploiting the three stable states of a tristable flexible mechanism so as to orient the articulation of the module at three distinct stable angles is first presented. Then a prototype of a modular snake-like robot is built and experimentally evaluated. The prototype consists of 4 modules that can be individually oriented by <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"><tex-math notation="LaTeX">$\pm$</tex-math></inline-formula> 7.1 degrees. Each module measures 51.5 × 32 mm and weighs 2.5g. Thereby, this work provides the first results on the feasibility of this robotic architecture which consists of several multistable modules. A good agreement between the working space estimated with the direct kinematic model and experimental measurements is obtained. According to the fact that these are preliminary results, there is a 1.5% error between the experimental results and the models.

Mechatronics Around the World - at a Glance

Increasing performance standards for complex procedures, which includes business equipment and their steadily growing technical importance, might require new processes to be applied within the procedure of product advent. The important thing concept in the back of our proposed approach is to combine one of a kind stages consisting of design, simulation and physical implementations in product or device advent. The distinguishing characteristic of mechatronic structures is illustrated in this study by using intensive integration. The mechatronic model allows us to better understanding the additive's complex behavior and interactions. This affords accelerated opportunities for the dynamic movement performance of the entire device to be measured and optimized inside the early levels of the layout process. The developing effect of interactions among machine additives on attainable gadget dynamics and accuracy is every other consequence. In this study, a concept for mechatronics is proposed to satisfy these requirements with the help of multiple diagrams and various applications.

Design and virtual model of an exoskeleton for lower limb rehabilitation

In this paper the design and the virtual model of an exoskeleton for human lower limb rehabilitation is developed. The proposed exoskeleton is anthropomorphic, low cost and easy to adapt on the human subject. The design aspect concerns the exoskeleton mechatronic structure achieved in Solid Works virtual environment. In order to realize the multibody model, the virtual spatial model of a human mannequin developed in SolidWorks was transferred to the ADAMS database. The movement laws experimentally collected are introduced in each of the 6 rotational joints of the both lower limbs. Simulation of the mannequin walking is performed.

HEGEMONYA ETKİSİNDE SİBERPUNK VE DİSTOPİK GERÇEKLİK: GEÇMİŞİN GELECEĞİ OLARAK GÜNÜMÜZ

Human is an entity that can create different living spaces for itself by changing its environment as desired. Like other creatures, can eliminate it by using its existing mind to have different equipment. At the same time, he may lose his blessing by entering the race to rule nature and people. In hegemonic structures, these situations can be seen in the world where quality of life deteriorates as technology develops and in fiction. The bodies of people are equipped with mechatronic implants, the functions of artificial intelligence are developed based on the human brain. A symbiotic relationship occurs between organic and mechatronic structures. It is believed that the person who artificializes himself and his environment meets with fictionalized in the past. Especially since 1970s, the original discoveries of scientists and researchers, the claims of various novel writers about technological developments, create new discussion environments, draw attention to concepts such as digital people, cyber culture, cyberpunk, which are frequently discussed in cinema and literature. The idea that rapidly developing technology will be used to the detriment of humanity and that the future will not be very bright constitutes the content of novels. In this study, the ignorant approaches of focus on power that shape the future; punk culture and “cyberpunk” transformation, which exhibit a protest attitude towards the chaotic structures that technological developments will determine in the future; The dystopic reality of generations that are trying to adapt to every technology and are not questioned will be evaluated. The relationship between will be explained with the examples that hegemony, cyberpunk and reality. With the scientific studies in this research, it is aimed to increase of individual awareness and social consciousness.

Temporal Auto-Correlation Function Pushed to One Pixel Limit

Quantum transport in a neutral atom guide provides intriguing quantum effects that are important aspects in designing atom mechatronic structures such as quantum interferometer, pump, valve, and amplifier structures. We investigate applicability of spatial reduction in temporal auto-correlation function to reduce computational resources in finding eigen-energy inside the guide. We find that we can reduce the size of the correlation function to an area 65,536 times smaller than the entire simulation space (0.0015%), which corresponds to an area of one pixel. The maximum error of all energies is 8.18% for a ground state and the trend of errors reduces exponentially as the principle quantum number increases. The setting of the investigation involves initial Gaussian wave packet evolving in a 2D harmonic potential and the correlation space is concentric to the center of the initial wave packet.

Efficient Static and Dynamic Modelling of Machine Structures with Large Linear Motions

Mechatronic structures deform under static and dynamic loads. These deformations lead to deviations at the tool center point (TCP), affecting the reachable accuracy and/or productivity of the machines. The scope of this work is the comparison of calculations and measurements of different static and dynamic errors on a dynamic test bench. A reduced-order modelling approach is applied for the test bench modelling. It uses a combination of modal condensation and moment-matching methods with Krylov subspaces. The different modelling steps and requirements are presented. The same model is used for all static and dynamic evaluations presented within this paper. Static deformations, leading to roll and pitch deviations at the TCP of the test bench structure, are simulated using the described modelling methodology and validated by inclination measurements. The modal behavior of the system is investigated by calculation and compared to the measurements at a single axes position. The spatial change of the frequency response functions of the modelled system is investigated further, by calculation and measurement of the velocity open-loop FRFs of one axis for different machine configurations. In addition, a transient trajectory simulation is performed and compared to the Heidenhain KGM and encoder measurements. The large variety of comparisons shows the efficient applicability of the modelling environment MORe.

Design and evaluation of a new exoskeleton for gait rehabilitation

Abstract. This work addresses the design and numerical characterization of a new exoskeleton solution for human leg motion assistance and rehabilitation. The exoskeleton solution is anthropomorphic, simple, low cost and easy to adapt on the human subject. The design aspect concerns the exoskeleton mechatronic structure, achieved in SolidWorks virtual environment. Numerical simulation is performed in MSC.ADAMS simulation environment. Obtained results for the exoskeleton computed motion are compared with those obtained from experimental walking of healthy subject. The prototype feasibility is studied both for design and operation aspect.

Design and Control of a Robotic Platform for Dexterous Minimally Invasive Surgical Applications

In this article, a novel robotic platform for robotic assisted minimally invasive surgical operations is presented. The platform consists of a 3 Degree-of-Freedom (DoF) passive tool holder and a 12 DoF robotic probe for dexterous motion upon insertion. The developed prototype is presented in terms of its mechatronic and kinematic structure. Regarding actuation, a hybrid solution comprising of servo-motors for the extraoperative part of the robot and shape-memory-alloy actuators for the intraoperative probe is adopted. The latter are evaluated in terms of establishing an efficient antagonistic tendon-driven actuation control scheme. The robotic platform is in-vitro evaluated under a human-in-the-loop control scheme using a teleoperation device. Additionally, custom developed software for physicians’ training and pre-operative planning with the robot is presented.

Negative Resistance in Discrete Mechatronic Systems

In the paper, the problem of negative resistance has been studied. Considered systems are limited to mechatronic discrete structures that contains mechanical part and piezoelectric actuator in form of stack, connected to external electric network that include the resistance elements which can have and receive negative values. The study have been done based on examples of branched structures, received as a result of solving the reverse task, and is aimed for parameters, limits and constrains evaluation. The paper extends possible applications of piezostack actuators and applied configurations that utilize negative resistance for vibration control.

Development and Analysis of a Novel Parallel Manipulator Used in Four-Dimensional Radiotherapy

Radiotherapy (RT) enables a selective destruction of tumor cells, although the treatment area is limited to the irradiated volume. Any RT technique comes along with multiple sources of error, which can lead to a deviation of the dose that is applied to the patient. Phantoms—structures that replicate a human and include measurement technology to assess the applied dosage—are used to make such errors observable. Past RT-technologies assumed static tumors. Correspondingly, most existing phantoms comprise only static components. Nowadays, RT is at a transition stage toward techniques which explicitly account for physiological motion. These techniques require phantoms generating such motion. Consequentially, a demand for new kinds of manipulators, which operate with a RT-phantom, has come up and will further increase in the future. Key demands of such manipulators are among others, the generation of full rigid body motion, high acceleration, high stiffness, compactness, little weight, and easy portability. Another indispensable feature is the spatial separation of mechatronic components and phantom structure to ensure human equivalency of the latter. In this work, a new kind of parallel kinematic manipulator (PKM), which is tailored to the requirements of RT-phantom technology, is presented. The PKM consists of low cost standardized mechanical components and sets the target structures, which are located inside a human-equivalent area, into translational and rotational motion in three degrees-of-freedom (DOFs). Only a part of the end-effector is located within the human-equivalent area. All the remaining parts of the PKM are located outside that area. Two versions of the manipulator are presented in detail: their kinematics are derived and their kinetostatic properties are compared. This includes a workspace analysis and the analysis of the transmission behavior in general, meaning the influence of the most important design parameters on the performance. It can be shown that practical differences of both kinematics are negligible, while the modified version provides significant mechanical advantages. In conclusion, a first special purpose manipulator for application in the evolving field of RT-phantom technology is presented. The PKM, which employs a novel kinematic structure, provides higher suitability for its purpose than any other robotic system employed so far for the same purpose.

Forces of a 3R Robot

In this study, one presents a method for determination of kinetostatic parameters in dyad 3R. It starts with the determination of the forces in the joints: RB, RD, R23. To generalize the method including for the 2R robots, enter both the moments M1, M2. This module (2R) is the main module found in all rotating anthropomorphic robotic structures and similar mechatronic structures. If there are additional external forces such as technological resistances, they will also be added. The forces acting within a mechanism are of particular importance in that they give the dimensions of the mechanism, the elements of the mechanism so that it can withstand all the static and dynamic loads during its operation. For this reason, it is important to know all the forces acting on the elements but especially on the kinematic couplers, both for the correct dimensioning of these elements and for the proper functioning of the respective mechanism. Forces together with kinematics are, on the other hand, basic components of dynamic calculations for that mechanism. This is also true for robots. Science that deals with the determination of forces within a mechanism is called Kinetostatic. The calculations within a mechanism are made on the pieces of this mechanism called structural groups or structural modulus. The structural modules of a mechanism are determined on the basis of the principle of eliminating the mobility of the respective group in the desmodromic mechanisms. The mobility of the mechanism is given either by other movable input elements that are added to the structural groups or to the robots by adding some actuators to the elements of a module.

Formalization of Discrete Mechatronic Systems with Negative Value Parameters

In the paper, the problem of designing of mechatronic discrete systems for vibration control has been investigated and generalized. As the design method, the synthesis has been used. Main focus of the paper is given to formalization of the mechatronic structures that contains elements with negative values on different stages of the synthesis process. The study is done based on different distributions methods of dynamical characteristics, dimensionless transformation and retransformation algorithm, simultaneously with verification of possible configurations of connections of piezostack actuators with external electric networks. As the result, various classifications of mechatronic discrete systems and general design constrains have been presented and discussed.

The Reverse Task of Discrete Mechatronic Vibration Systems With Negative Stiffness and Capacitance Elements

Abstract By the use of different distribution methods of dynamical characteristics in the form of slowness function, mechatronic discrete systems have been synthesized. Each model consists of mechanical discrete part and a piezostack actuator connected to LxRxCx external network that has to comply with dynamical requirements in the form of poles and zeros. External network can work within different configurations. In this paper, one investigates the influence of negative parameters of stiffness in mechanical replacement models and capacitance in final mechatronic structures, after dimensionless transformations and retransformations

Biomimetic Design for Unmanned Aerial Vehicle Safe Landing in Hazardous Terrain

Unmanned aerial vehicles capable of hazardous terrain landing are desirable for intelligence collection. A crucial point is the landing gear's autonomous adaptation to the rough surface, which is especially difficult in an unknown and constrained environment. To enable this capability, this paper proposes a novel biomimetic system that ascertains terrain appearances like large obstacles and precipitous slope using a monocular camera and adjusts the mechatronics landing structure according to the terrain. A dynamic model including the ground effect is provided and a time-to-contact theory-based backstepping nonlinear controller is designed to reject uncertainty disturbances as well as implement a bio-inspired guidance strategy for soft landing in hazardous terrain. The mechatronic architecture and cascade control structure using custom-built unmanned air vehicle platform are presented. Experimental results and video footage demonstrate this biomimetic approach efficiently controls a vehicle successfully landing in an unknown and unstructured constrained environment.

Modeling and control of a novel X–Y parallel piezoelectric-actuator driven nanopositioner

In this paper, a novel X–Y parallel piezoelectric-actuator driven nanopositioner is studied from the perspectives of design optimization, dynamical modeling, as well as controller synthesis for high precision positioning. FEM (Finite Element Method) and dynamical modeling are provided to analyze the mechatronic structure of the proposed two-dimensional nano-stage, where the system model, including the hysteresis loop, is derived analytically and further verified experimentally. A robust control architecture incorporating an H∞ controller and an anti-windup compensator is then developed to deal with the hysteresis and saturation nonlinearities of the piezoelectric actuators. Real time experiments on the nano-stage platform demonstrate good robustness, high precision positioning and tracking performance, as well as recovery speed in the presence of saturation.

Shape memory alloy-based smart module structure working under intense thermo-mechanical stress

The paper presents a complete model for a modular mechatronic structure actuated by a one-way memory effect shape memory alloy actuator. In order to claim the complete attribute of the model, the austenite transformation temperature evolution of actuator was evaluated in relation with the precision and repeatability related capabilities of the mechatronic structure. The evolution of austenite transformation temperature was obtained through determinations based on DSC method. Those determinations were performed on the shape memory alloy wire used as actuator in the modular mechatronic structure. The wire is subject of intense and repetitive operating mode. All determinations are performed on the SMA wire used as actuator system after 5,000, and 1,003,600 cycles, respectively. The results indicate a shift in both A s and A f temperatures, a trend that is heavily dependent on the operating history of the system. Using experimental results, authors built a graph (surface) that is based on heating time schedule, heating current, and austenite finish temperature. Also, the results lead to the conclusion that for any desired heating time, it can be identified (in a restricted but relatively wide range), at least a pair of both austenite finish temperature and heating current. If the control algorithm modifies the electrical current in accordance with the number of working cycles and austenite transformation temperature evolution, the time response and, by default, the structure repeatability are assured even after over 1 million working cycles.

An Automatic Assembly Technology for Perforated Discs Based on Contour Optimized Hough Circle Transform

Aiming at the low efficiency of handwork and high labor intensity, an automatic solution for perforated discs assembly is developed based on computer vision. This technology consists of the processes of material feeding, parts handling, circle detecting and assembling. The mechatronic structure includes the pneumatic elements and electric actuators that controlled by PLC and stepper motor drivers. This method has solved the problem of the large cost of human force since this product has a big industrial production. Meanwhile, a contour optimized Hough circle transform (CHCT) is proposed. It can overcome the standard Hough circle transform (HCT) s disadvantages, such as redundant calculation and probability of failures. It enhances the reliability in order to satisfy the demand of industrial automatic production. The image processing takes only about 60ms and reaches 100% success rate with a small detection error. This method also has the generality for the similar assembly system based on machine vision.

KINETOSTATIC OF THE 3R DYAD

This paper presents a method to determine the kinetostatic parameters at the 3R dyad. One proposes to determine the forces from joints: RB, RD, R23. To generalize the method and to the 2R robots, are introduced and the two moments M1, M2. This 2R module, is the principal from the android rotation robotic structures and mechatronic structures. Figure 1 shows a schematic diagram of the 3R dyad minimum kinetostatic (loaded with the inertia forces, considered external forces). For if there are additional external forces, such as technological resistances will be added as well.

Augmentation of Propulsion Based on Coil Array Commutation for Magnetically Levitated Stage

This paper focuses on augmenting the propulsion via commutation of coil array for the long-stroke magnetically levitated stage with moving coils, whose mechatronics structure have been defined. The used commutation of coil array is based on the analytical force/torque-decomposing model of the stage and it is characterized by bounding the coil currents. Through this current-bounded commutation, the 1-norm of commutated coil current vector is increased so that the propulsion can be augmented, and simultaneously the infinite norm of commutated coil current vector is limited so that the amplitudes of commutated coil currents are not beyond the capacity of selected coil power amplifiers. By the investigation example of a long-stroke magnetically levitated stage with moving coils, it is theoretically verified that the propulsion (acceleration) can be augmented by 125% as well as the commutated coil currents can be kept within the capacity of selected coil power amplifiers, 3 A. The study results indicate that the propulsion of a magnetically levitated stage can be augmented via current-bounded commutation of coil array rather than via reconfiguring the mechatronics structure of stage or reselecting coil power amplifiers of larger capacity.

Reverse task as a designing of mechatronic vibrating branched systems

AbstractIn this paper a new approach for designing mechatronic vibrating branched structures has been presented. Mechatronic structures have been built from mechanical discrete systems connected to piezoelectric actuator and externalLxRxCx network, with different configurations. Modeling simplification has been performed by use of non dimensional transformations and retransformations. In each case reverse task has been solved by distribution into partial fraction method in respect to required dynamic properties in form of frequency spectrum: resonant and anti resonant frequencies. Furthermore, different configurations of final LxRxCx network have been presented. These considerations have been supported by calculation examples, and all results have been presented in the graphical form. (© 2011 Wiley‐VCH Verlag GmbH &amp; Co. KGaA, Weinheim)