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Lower extremity exoskeleton is a kind of wearable robot and is used both in medical and industrial applications for different purposes. In the medical field it is used as a piece of therapeutic equipment and in the industry especially in defense, to carry heavy loads. This paper deals with the analysis of the performance of super twisting sliding mode controller (STSMC) on tracking the motion of the wearer by the lower extremity exoskeleton using automatic dynamic analysis of mechanical systems (ADAMS)–MATLAB co-simulation during walking and step climbing and the results are compared with a conventional PID controller. The model of the lower extremity exoskeleton is developed by solid-works software and the model of the human body is done with ADAMS software. Super twisting sliding mode controller (STSMC) is designed and simulated with Simulink. This paper also aims to develop a mathematical model of the system and analyze the performance of STSMC to control hip, knee, and ankle movements and also to point out the advantages of the ADAMS–MATLAB co-simulation over the conventional methods of modeling and simulation analysis of the controller to control the exoskeleton. Stability analysis of the controller is also done.

This article proposed a new cross shaped cantilever beam with C shaped proof mass to enhance the voltage, power output of the cross shaped cantilever with C shaped proof mass .Analysis has been carried out using numerical simulation for the structures with rectangular and C shaped proof mass by keeping the volume of proof mass as constant. The resonant frequency , output voltage and power output of the cross shaped cantilever beam were studied by using COMSOL 4.4 software.it has been proved that cross shaped cantilever beam with C shaped proof mass produce high voltage and high power as compared to cross shaped cantilever with rectangular proof mass under same vibration conditions.

In this paper, a new approach to model reference based adaptive second-order sliding mode control together with adaptive state feedback is presented to control the longitudinal dynamic motion of a high speed train for automatic train operation with the objective of minimal jerk travel by the passengers. The nonlinear dynamic model for the longitudinal motion of the train comprises of a locomotive and coach subsystems is constructed using multiple point-mass model by considering the forces acting on the vehicle. An adaptation scheme using Lyapunov criterion is derived to tune the controller gains by considering a linear, stable reference model that ensures the stability of the system in closed loop. The effectiveness of the controller tracking performance is tested under uncertain passenger load, coupler-draft gear parameters, propulsion resistance coefficients variations and environmental disturbances due to side wind and wet rail conditions. The results demonstrate improved tracking performance o...

A piezoelectric cantilever beam-based energy harvester working with solar energy is proposed in this paper. The piezoelectric cantilever beam is excited by a shape memory alloy (SMA) spring actuator. The heating and cooling of the SMA actuator is done by designing an appropriate piping and transport system with water as a working fluid. The frequency and amplitude of excitation force exerted by an SMA actuator to the piezoelectric cantilever beam depend on the flow rate of water used for heating and cooling of SMA and the temperature of the water. The energy harvester is modeled analytically and fabricated to evaluate its performance in the laboratory. The analytical and experimental results show that higher output voltage from the energy harvester can be obtained with higher water temperature and frequency of the output voltage is limited to the dynamics of the SMA actuator. The voltage generated with the proposed energy harvester at the flow rate of 24ml/s with the temperature of ${\bf {70}}^\circ {\bf C}$ is found to be 12 V. The harvester utilizes only the solar energy for its operation and hence the proposed design is a new addition to the area of energy harvesting using piezoelectric cantilever beam.

This paper presents a cantilever structure as energy harvester by introducing a trapezoidal cavity to increase the amplitude of the generated voltage and the overall mechanical to electrical energy conversion efficiency. An analytical model of the proposed structure is developed using Euler-Bernoulli beam theory. The effect of taper angle of the trapezoidal cavity and the neutral axis shift on the generated voltage is analyzed using analytical model and through experimentation. The generated output voltage from the energy harvester with trapezoidal cavity is compared with the beam having rectangular cavity and the beam without cavity. The generated voltage for the beam with trapezoidal cavity is 97.5% and 108% higher as compared with the beam having rectangular cavity and the beam without cavity. The characteristics of the energy harvester are evaluated through analytical model and experimentation and the results are in close agreement.

This paper presents modeling and experimental evaluation of a cantilever-based piezoelectric energy harvester with cavity. The introduction of cavity in the beam shifts the neutral axis of the beam away from the surface of the piezoelectric element which in turn increases the strain and generated voltage. The generated voltage from the cantilever beam with cavity is higher when compared to the beam without cavity and is found to vary with its position and thickness. The analytical and experimental results are in close agreement. The cantilever beam with cavity generates 75% higher voltage than the voltage generated from the beam without cavity.

This paper presents the design and experimental evaluation of discrete time sliding mode controller using multirate output feedback to minimize structural vibration of a cantilever beam using shape memory alloy wires as control actuators and piezoceramics as sensor and disturbance actuator. Linear dynamic models of the smart cantilever beam are obtained using online recursive least square parameter estimation. A digital control system that consists of Simulink™ modeling software and dSPACE DS1104 controller board is used for identification and control. The effectiveness of the controller is shown through simulation and experimentation by exciting the structure at resonance.

The overall percentage of child abusements filed nowadays in the world is about 80%, out of which 74% are girl children and the rest are boys. For every 40 seconds, a child goes missing in this world. Children are the backbone of one’s nation, if the future of children was affected, it would impact the entire growth of that nation. Due to the abusements, the emotional and mental stability of the children gets affected which in turn ruins their career and future. These innocent children are not responsible for what happens to them. So, parents are responsible for taking care of their own children. But, due to economic condition and aims to focus on their child’s future and career, parents are forced to crave for money. Hence, it becomes difficult to cling on to their children all the time. In our system, we provide an environment where this problem can be resolved in an efficient manner. It makes parents to easily monitor their children in real time just like staying beside them as well as focusing on their own career without any manual intervention.

Inherent scarcity of thermal sources with a time varying temperature profile is the reason why the pyroelectric-based energy harvesting is not as prominent as its counterpart, thermoelectric generators, in the thermal energy harvesting domain. In this paper, a practical solution for generating thermal oscillations required for sustainable pyroelectric-based energy harvesting from the solar and wind energies, is presented. The main focus of the work is to modulate the concentrated solar radiation using a vertical axis wind turbine for producing higher rate of change of temperature on the pyroelectric material. The maximum energy and power density produced by the prototype device using PZT-5H as pyroelectric material are 6.927 mJ/cm3/cycle and 421.18 μW/cm3, respectively, and on average it can produce a power density of 304.78 μW/cm3, which concurs with the theoretical model.

The benefits of multisensor data fusion (MSDF) in controlling the piezo actuated beam structure using sliding mode controller (SMC) has been brought out. The first two vibrating modes of the smart cantilever beamare measured by two sensors namely, piezoelectric sensor and laser displacement sensor. The states are estimated from the sensors outputs using information filter, which were then fused and applied as input to the controller. The controller has been designed from the linear dynamic model of a piezo actuated beam, identified using linear recursive least square (RLS) method based on ARX model. A digital control system consisting of virtual instrumentation software LabVIEW, and USB data acquisition module NI 6008, was used for simulation and real-time control. Improved closed-loop performance was obtained when the controller designed used fused data, as compared to the closed-loop performance obtained with a single sensor. The beam structure considered in this work was a pilot model of the structures used in aerospace applications. Simulation and experimental results presented demonstrate the benefits of data fusion in controlling the vibration modes. Defence Science Journal, 2011, 61(4), pp.346-353 , DOI:http://dx.doi.org/10.14429/dsj.61.1114

A Fast output sampling feedback controller is designed and implemented for vibration control of piezoelectric actuated beam structure using an interval method. Uncertainties which are assumed in the model, are identified through on line recursive least square parameter estimation. The control and identification process is done by using Simulink modeling software and a dSPACE DS 1104 controller board.

This paper presents the design and the experimental implementation of fast and periodic output feedback controllers to minimize structural vibration, using collocated piezoelectric actuators and sensors. A linear dynamic model of the smart cantilever beam is obtained using online recursive least squares parameter estimation. A digital control system that consists of simulink modeling software and a dSPACE1104 controller board has been used for identification and control. The effectiveness of the controllers is shown experimentally by exciting the structure at resonance.

The paper presents a novel design and development of a resonant sensor to measure thickness of ferromagnetic sheets and their alloys. The sensor is built with cantilever beam as a resonator with electromagnetic excitation and piezoelectric sensing in closed loop electronics. The sensor measures the unknown thickness by measuring the resonance frequency of the resonator. The magnetic force due to the magnetic field interaction between electromagnet and ferromagnetic sheet will make the resonator at resonance. The resonator vibrates at different resonance frequencies depending on the thickness of the ferromagnetic sheet. The shift in resonance frequency for a change in thickness is detected by closed loop electronics. The proposed system is simple and varies linearly with thickness in the given measurement range and the sensitivity is improved by increasing the magnetic field strength of the electromagnet.

Precision Green house management based agriculture is a combination of integrated information and production-based farming system that is designed to increase long term site-specific farm production efficiency and profitability while minimizing unintended effects on green house environment. It requires intensive sensing of the climate conditions at ground level and rapid communication of data to the central repository. Wireless sensor network is an emerging field that can be used to monitor and control the agriculture parameters in order to make intelligent automated agriculture system inside the green house. The system basically comprises of CPU for monitoring the data in LABVIEW platform and Zigbee module along with PIC microcontroller to establish wireless communication between two distant locations. The main purpose of the work undertaken in this paper is to sense, monitor and control the temperature, humidity and irrigation in the greenhouse from remote location using the Zigbee technology at low cost. The wireless transceiver is configured using TMFT 2.6 software provided by Melange Systems and PIC microcontroller is programmed using Microchip's IDE version 8.2. This technology is intended to be the simpler and cheaper than any other WPANs such as Bluetooth or wireless internet node. In the present work the data from sensing node after amplification is fed to ADC and then to the microcontroller. This is then connected to the Zigbee module which transmits the data to the Zigbee module at the other end. It reads the data and displays on to the host computer through Labview and the control sequence is generated to control the green house parameters from the control room wirelessly.

This paper presents the design and experimental implementation of second order sliding mode (SOSM) control using super twisting algorithm to minimize structural vibration. A linear dynamic model of the smart cantilever beam is obtained using online recursive least square method and information filter is used for state estimation. A digital control system that consists of simulink modeling software and dSPACE 1104 controller board has been used for implementation. The effectiveness of the controllers for rejecting uncertainty is shown experimentally by exciting the structure at resonance with added tip mass and at elevated temperatures.

In this paper, the problem of modeling, output feedback control design and the experimental implementation for the vibration control of smart cantilever beam with parameter uncertainties represented in interval form is addressed. The interval model of the system is obtained by introducing variation in the parameter of the identified model. However, Uncertainties are assumed in the model, identified through on line recursive least square parameter estimation. The control and identification process is done by using Simulink modeling software and dSPACE DS 1104 controller board. The output feedback controller design for the interval model is carried out through simultaneous output feedback controller design methodology by considering lower, nominal and upper bound models. The controllers designed are periodic output feedback is experimentally evaluated for their performance in suppressing the first vibration mode.

This paper presents the design and experimental implementation of a simultaneous periodic output feedback controller to minimize structural vibration using collocated piezoelectric actuator and sensor. The linear dynamic model of piezoelectric-bonded cantilever beams is obtained using online recursive least-square parameter estimation. A digital control system that consists of simulink modelling software and dSPACE 1104 controller board is used for identification and control. The performance of simultaneous controller is evaluated by considering a cantilever beam structure of three different lengths and mass. The effectiveness of the controller is demonstrated experimentally by exciting the structures at resonance. The advantage of the simultaneous periodic output feedback controller implemented in this paper is unique in the sense that the common controller gain reduces the first two vibration modes of three plants, which is not commonly shown in the literature with other feedback controllers. From the experimental results it is observed that with the simultaneous output feedback controller the vibration reduction is approximately 75% for the first mode and 60% for the second mode for all the three plants. Copyright © 2008 John Wiley & Sons, Ltd.

This paper presents the design of reaching law based discrete time sliding mode control for the SMA actuated cantilever beam to suppress the vibration in the presence of external disturbance. A linear dynamic model of the SMA actuated cantilever beam structure is experimentally established using online ARX RLS system identification approach. A digital control system that consists of simulink modeling software and dSPACE 1104 controller board has been used for identification. The VSC controller is designed starting with the switching surface design. The eigen values of the reduced order system are located suitably so that it lies inside the unit circle and the system is stable. The performance of the controller for vibration suppression and disturbance rejection was evaluated through simulation by exciting the structure at resonance.

This paper proposes a composite output feedback controller which consists of periodic output feedback and fast output sampling feedback controller. Each of the controllers is designed to suppress the particular vibration mode. The proposed controller is applied to control the first two vibration modes of a piezoelectric actuated cantilever beam. The performance of the controller is shown by simulation and experimental results. A digital control system that consists of simulink modeling software and dSPACE 1104 controller board is used for identification and control.

This paper presents the design and experimental evaluation of sliding mode controller to minimise structural vibration of a cantilever beam using shape memory alloy (SMA) wires as control actuators and piezoceramics as sensor and disturbance actuator. Linear dynamic models of the smart cantilever beam are obtained using online recursive least square parameter estimation. A digital control system that consists of Simulink™ modelling software and dSPACE DS1104 controller board is used for identification and control. The effectiveness of the controller is shown through simulation and experimentation by exciting the structure at resonance.

This paper presents the design and experimental implementation of simultaneous fast output sampling feedback controller to minimise structural vibration using collocated piezoelectric actuator and sensor. The linear dynamic model of piezoelectric bonded cantilever beams is obtained using online recursive least square parameter estimation. A digital control system that consists of simulink modelling software and dSPACE 1104 controller board is used for identification and control. The performance of simultaneous controller is evaluated by considering three structure models. These models are obtained by introducing parameter variation in length and mass of a single cantilever beam structure. The effectiveness of the controller is demonstrated experimentally by exciting the structures at resonance.

This paper presents the design and experimental evaluation of periodic output feedback controller to minimise structural vibration of a cantilever beam using shape memory alloy (SMA) wires as control actuators and piezoceramics as sensor and disturbance actuator. Online recursive least square parameter estimation is used to obtain linear dynamic models of the smart cantilever beam. Simulink™ modelling software and dSPACE DS1104 controller board are used for identification and control. The performance of the controller is evaluated experimentally at resonance.

This paper presents the design and experimental evaluation of fast output sampling feedback controller to minimize structural vibration of a cantilever beam using Shape Memory Alloy (SMA) wires as control actuators and piezoceramics as sensor and disturbance actuator. Linear dynamic models of the smart cantilever beam are obtained using online recursive least square parameter estimation. A digital control system that consists of Simulink modeling software and dSPACE DS1104 controller board is used for identification and control. The effectiveness of the controller is shown through simulation and experimentation by exciting the structure at resonance.