Abstract: An array of piezoelectric micro actuators can be used
for radiation of an ultrasonic carrier signal modulated in amplitude
with an acoustic signal, which yields audio frequency applications as
the air acts as a self-demodulating medium. This application is
known as the parametric array. We propose a parametric array with
array elements based on existing piezoelectric micro ultrasonic
transducer (pMUT) design techniques. In order to reach enough
acoustic output power at a desired operating frequency, a proper ratio
between number of array elements and array size needs to be used,
with an array total area of the order of one cm square. The
transducers presented are characterized via impedance, admittance,
noise figure, transducer gain and frequency responses.
Abstract: A multi fingered dexterous anthropomorphic hand is
being developed by the authors. The focus of the hand is the
replacement of human operators in hazardous environments and also
in environments where zero tolerance is observed for the human
errors. The robotic hand will comprise of five fingers (four fingers
and one thumb) each having four degrees of freedom (DOF) which
can perform flexion, extension, abduction, adduction and also
circumduction. For the actuation purpose pneumatic muscles and
springs will be used. The paper exemplifies the mechanical design for
the robotic hand. It also describes different mechanical designs that
have been developed before date.
Abstract: The psychological and physical trauma associated with the loss of a human limb can severely impact on the quality of life of an amputee rendering even the most basic of tasks very difficult. A prosthetic device can be of great benefit to the amputee in the performance of everyday human tasks. This paper outlines a proposed mechanical design of a 12 degree-of-freedom SMA actuated artificial hand. It is proposed that the SMA wires be embedded intrinsically within the hand structure which will allow for significant flexibility for use either as a prosthetic hand solution, or as part of a complete lower arm prosthetic solution. A modular approach is taken in the design facilitating ease of manufacture and assembly, and more importantly, also allows the end user to easily replace SMA wires in the event of failure. A biomimetric approach has been taken during the design process meaning that the artificial hand should replicate that of a human hand as far as is possible with due regard to functional requirements. The proposed design has been exposed to appropriate loading through the use of finite element analysis (FEA) to ensure that it is structurally sound. Theoretical analysis of the mechanical framework was also carried out to establish the limits of the angular displacement and velocity of the finger tip as well finger tip force generation. A combination of various polymers and Titanium, which are suitably lightweight, are proposed for the manufacture of the design.
Abstract: An information procuring and processing emerging technology wireless sensor network (WSN) Consists of autonomous nodes with versatile devices underpinned by applications. Nodes are equipped with different capabilities such as sensing, computing, actuation and wireless communications etc. based on application requirements. A WSN application ranges from military implementation in the battlefield, environmental monitoring, health sector as well as emergency response of surveillance. The nodes are deployed independently to cooperatively monitor the physical and environmental conditions. The architecture of WSN differs based on the application requirements and focus on low cost, flexibility, fault tolerance capability, deployment process as well as conserve energy. In this paper we have present the characteristics, architecture design objective and architecture of WSN
Abstract: A numerical investigation of the effects of nanosecond
barrier discharge on the stability of a two-dimensional free shear layer
is performed. The computations are carried out using a compressible
Navier-Stokes algorithm coupled with a thermodynamic model of the
discharge. The results show that significant increases in the shear
layer-s momentum thickness and Reynolds stresses occur due to
actuation. Dependence on both frequency and amplitude of actuation
are considered, and a comparison is made of the computed growth
rates with those predicted by linear stability theory. Amplitude and
frequency ranges for the efficient promotion of shear-layer instabilities
are identified.
Abstract: Small satellites have become increasingly popular recently as a means of providing educational institutes with the chance to design, construct, and test their spacecraft from beginning to the possible launch due to the low launching cost. This approach is remarkably cost saving because of the weight and size reduction of such satellites. Weight reduction could be realised by utilising electromagnetic coils solely, instead of different types of actuators. This paper describes the restrictions of using only “Electromagnetic" actuation for 3D stabilisation and how to make the magnetorquer based attitude control feasible using Fuzzy Logic Control (FLC). The design is developed to stabilize the spacecraft against gravity gradient disturbances with a three-axis stabilizing capability.
Abstract: This paper presents the control performance of a high-precision positioning device using the hybrid actuator composed of a piezoelectric (PZT) actuator and a voice-coil motor (VCM). The combined piezo-VCM actuator features two main characteristics: a large operation range due to long stroke of the VCM, and high precision and heavy load positioning ability due to PZT impact force. A one-degree-of-freedom (DOF) experimental setup was configured to examine the fundamental characteristics, and the control performance was effectively demonstrated by using a switching controller. In rough positioning state, an integral variable structure controller (IVSC) was used for the VCM to conduct long range of operation; in precision positioning state, an impact force controller (IFC) for the PZT actuator coupled with presliding states of the sliding table was used to obtain high-precision position control and achieve both forward and backward actuations. The experimental results showed that the sliding table having a mass of 881g and with a preload of 10 N was successfully positioned within the positioning accuracy of 10 nm in both forward and backward position controls.
Abstract: Presents a concept for a multidisciplinary process
supporting effective task transitions between different technical
domains during the architectural design stage.
A system configuration challenge is the multifunctional driven
increased solution space. As a consequence, more iteration is needed
to find a global optimum, i.e. a compromise between involved
disciplines without negative impact on development time. Since state
of the art standards like ISO 15288 and VDI 2206 do not provide a
detailed methodology on multidisciplinary design process, higher
uncertainties regarding final specifications arise. This leads to the
need of more detailed and standardized concepts or processes which
could mitigate risks.
The performed work is based on analysis of multidisciplinary
interaction, of modeling and simulation techniques. To demonstrate
and prove the applicability of the presented concept, it is applied to
the design of aircraft high lift systems, in the context of the
engineering disciplines kinematics, actuation, monitoring, installation
and structure design.
Abstract: Deployment of pneumatic muscles in various
industrial applications is still in its early days, considering the relative
newness of these components. The field of robotics holds particular
future potential for pneumatic muscles, especially in view of their
specific behaviour known as compliance. The paper presents and
discusses an innovative constructive solution for a gripper system
mountable on an industrial robot, based on actuation by a linear
pneumatic muscle and transmission of motion by gear and rack
mechanism. The structural, operational and constructive models of
the new gripper are presented, along with some of the experimental
results obtained subsequently to the testing of a prototype. Further
presented are two control variants of the gripper system, one by
means of a 3/2-way fast-switching solenoid valve, the other by means
of a proportional pressure regulator. Advantages and disadvantages
are discussed for both variants.
Abstract: The study of human hand morphology reveals that developing an artificial hand with the capabilities of human hand is an extremely challenging task. This paper presents the development of a robotic prosthetic hand focusing on the improvement of a tendon driven mechanism towards a biomimetic prosthetic hand. The design of this prosthesis hand is geared towards achieving high level of dexterity and anthropomorphism by means of a new hybrid mechanism that integrates a miniature motor driven actuation mechanism, a Shape Memory Alloy actuated mechanism and a passive mechanical linkage. The synergy of these actuators enables the flexion-extension movement at each of the finger joints within a limited size, shape and weight constraints. Tactile sensors are integrated on the finger tips and the finger phalanges area. This prosthesis hand is developed with an exact size ratio that mimics a biological hand. Its behavior resembles the human counterpart in terms of working envelope, speed and torque, and thus resembles both the key physical features and the grasping functionality of an adult hand.
Abstract: This paper presents a new stable robust adaptive controller and observer design for a class of nonlinear systems that contain i. Coupling of unmeasured states and unknown parameters ii. Unknown dead zone at the system actuator. The system is firstly cast into a modified form in which the observer and parameter estimation become feasible. Then a stable robust adaptive controller, state observer, parameter update laws are derived that would provide global adaptive system stability and desirable performance. To validate the approach, simulation was performed to a single-link mechanical system with a dynamic friction model and unknown dead zone exists at the system actuation. Then a comparison is presented with the results when there is no dead zone at the system actuation.
Abstract: In this paper, Fabless Prototyping Methodology is
introduced for the design and analysis of MEMS devices.
Conventionally Finite Element Analysis (FEA) is performed before
system level simulation. In our proposed methodology, system level
simulation is performed earlier than FEA as it is computationally less
extensive and low cost. System level simulations are based on
equivalent behavioral models of MEMS device. Electrostatic
actuation based MEMS Microgripper is chosen as case study to
implement this methodology. This paper addresses the behavioral
model development and simulation of actuator part of an
electrostatically actuated Microgripper. Simulation results show that
the actuator part of Microgripper works efficiently for a voltage range
of 0-45V with the corresponding jaw displacement of 0-4.5425μm.
With some minor changes in design, this range can be enhanced to
15μm at 85V.
Abstract: This paper presents a new type of mechanism and trajectory planning strategy for bipedal walking robot. The newly designed mechanism is able to improve the performance of bipedal walking robot in terms of energy efficiency and weight reduction by utilizing minimum number of actuators. The usage of parallelogram mechanism eliminates the needs of having an extra actuator at the knee joint. This mechanism works together with the joint space trajectory planning in order to realize straight legged walking which cannot be achieved by conventional inverse kinematics trajectory planning due to the singularity. The effectiveness of the proposed strategy is confirmed by computer simulation results.
Abstract: A glider is in essence an unpowered vehicle and in this project we designed and built an oceanic glider, designed to operate underwater. This Glider was designed to collect ocean data such as temperature, pressure and (in future measures physical dimensions of the operating environment) and output this data to an external source. Development of the Oceanic Glider required research into various actuation systems that control buoyancy, pitch and yaw and the dynamics of these systems. It also involved the design and manufacture of the Glider and the design and implementation of a controller that enabled the Glider to navigate and move in an appropriate manner.