Abstract: It is necessary to test to see if optical devices such as camera, night vision devices are working properly. Therefore, a precision biaxial rotary system (gimbal) is required for mounting Unit Under Test, UUT. The Gimbal systems can be utilized for precise positioning of the UUT; hence, optical test can be performed with high accuracy. The weight of UUT, which is placed outside the axis of rotation, causes an off-axis moment to the mounting armature. The off-axis moment can act against the direction of movement for some orientation, thus the electrical motor, which rotates the gimbal axis, has to apply higher level of torque to guide and stabilize the system. Moreover, UUT and its mounting fixture to the gimbal can be changed, which causes change in applied resistance moment to the gimbals electrical motor. In this study, a preloaded spring is added to the gimbal system for minimizing applied off axis moment with the help of four bar mechanism. Two different possible methods for preloading spring are introduced and system optimization is performed to eliminate all moment which is created by off axis weight.
Abstract: Since the invention, the electric machine (EM) can be defined as oEM – one-vector electric machine, as it works due to one-vector inductive coupling with use of one-vector electromagnet. The disadvantages of oEM are large size and limited efficiency at low and medium power applications. This paper describes multi-vector electric machine (mEM) based on multi-vector inductive coupling, which is characterized by the increased surface area of the inductive coupling per EM volume, with a reduced share of inefficient and energy-consuming part of the winding, in comparison with oEM’s. Particularly, it is considered, calculated and compared the performance of three different electrical motors and their power at the same volumes and rotor frequencies. It is also presented the result of calculation of correlation between power density and volume for oEM and mEM. The method of multi-vector inductive coupling enables mEM to possess 1.5-4.0 greater density of power per volume and significantly higher efficiency, in comparison with today’s oEM, especially in low and medium power applications. mEM has distinct advantages, when used in transport vehicles such as electric cars and aircrafts.
Abstract: The paper describes conceptual design, control strategies, and partial simulation for a new fully autonomous lower limb wearable exoskeleton system for human motion enhancement that can support its weight and increase strength and endurance. Various problems still remain to be solved where the most important is the creation of a power and cost efficient system that will allow an exoskeleton to operate for extended period without batteries being frequently recharged. The designed exoskeleton is enabling to decouple the weight/mass carrying function of the system from the forward motion function which reduces the power and size of propulsion motors and thus the overall weight, cost of the system. The decoupling takes place by blocking the motion at knee joint by placing passive air cylinder across the joint. The cylinder is actuated when the knee angle has reached the minimum allowed value to bend. The value of the minimum bending angle depends on usual walk style of the subject. The mechanism of the exoskeleton features a seat to rest the subject’s body weight at the moment of blocking the knee joint motion. The mechanical structure of each leg has six degrees of freedom: four at the hip, one at the knee, and one at the ankle. Exoskeleton legs are attached to subject legs by using flexible cuffs. The operation of all actuators depends on the amount of pressure felt by the feet pressure sensors and knee angle sensor. The sensor readings depend on actual posture of the subject and can be classified in three distinct cases: subject stands on one leg, subject stands still on both legs and subject stands on both legs but transit its weight from one leg to other. This exoskeleton is power efficient because electrical motors are smaller in size and did not participate in supporting the weight like in all other existing exoskeleton designs.
Abstract: The use of solar energy as a source for pumping water
is one of the promising areas in the photovoltaic (PV) application.
The energy of photovoltaic pumping systems (PVPS) can be widely
improved by employing an MPPT algorithm. This will lead
consequently to maximize the electrical motor speed of the system.
This paper presents a modified incremental conductance (IncCond)
MPPT algorithm with direct control method applied to a standalone
PV pumping system. The influence of the algorithm parameters on
system behavior is investigated and compared with the traditional
(INC) method. The studied system consists of a PV panel, a DC-DC
boost converter, and a PMDC motor-pump. The simulation of the
system by MATLAB-SIMULINK is carried out. Simulation results
found are satisfactory.
Abstract: The purpose of this work is to optimize a Switched Reluctance Motor (SRM) for an automotive application, specifically for a fully electric car. A new optimization approach is proposed. This unique approach transforms automotive customer requirements into an optimization problem, based on sound knowledge of a SRM theory. The approach combines an analytical and a finite element analysis of the motor to quantify static nonlinear and dynamic performance parameters, as phase currents and motor torque maps, an output power and power losses in order to find the optimal motor as close to the reality as possible, within reasonable time. The new approach yields the optimal motor which is competitive with other types of already proposed motors for automotive applications. This distinctive approach can also be used to optimize other types of electrical motors, when parts specifically related to the SRM are adjusted accordingly.
Abstract: Resistance spot welding (RSW) has been used widely to join sheet metals. It has been a challenge to get required weld quality in spot welding of dissimilar thickness materials. Weld parameters are not generally available in standards for thickness beyond 4mm. This paper presents the welding process design and parameter optimization of RSW used in joining of low carbon steel sheet of thickness 0.8 mm and metal strips of cross section 10 x 5mm for electrical motor applications. Taguchi quality design was adopted for weld current and time optimization using L9 orthogonal array. Optimum process parameters (current- 3.5kA and time- 10 cycles) were obtained from the Taguchi analysis and shear test results. Confirmation experiment result revealed that the weld quality was within acceptable interval. Further, numerical simulation of RSW process was carried out with selected weld parameters to quantify the temperature at faying surface and check for formation of appropriate nugget. The nugget geometry measured after peel test and predicted from numerical validation method were similar and in accordance with the standards.
Abstract: This study presents energy saving in general-purpose
pumps widely used in industrial applications. Such pumps are
normally driven by a constant-speed electrical motor which in most
applications must support varying load conditions. This is equivalent
to saying the loading conditions mismatch the designed optimal
energy consumption requirements of the intended application thus
resulting in substantial energy losses. In the held experiments it was
indicated that combination of mechanical and electrical speed drives
can contribute to lower energy consumption in the pump without
negatively distorting the required performance indices of a typical
centrifugal pump at substantially lower energy consumption. The
registered energy savings were recorded to be within the 15-40%
margin. It was also indicated that although VSDs are installed at a
cost, the financial burden is balanced against the earnings resulting
from the associated energy savings.
Abstract: The development of the power electronics has allowed
increasing the precision and reliability of the electrical trainings,
thanks to the adjustable inverters, as the Pulse Wide Modulation
(PWM) five level inverters, which is the object of study in this
article.The authors treat the relation between the law order adopted for
a given system and the oscillations of the electrical and mechanical
parameters of which the tolerance depends on the process with which
they are integrated (paper factory, lifting of the heavy loads,
etc.).Thus the best choice of the regulation indexes allows us to
achieve stability and safety training without investment (management
of existing equipment).
Abstract: Although electrical motors are still the main devices
used in vehicular exhaust comprises more than 95 percent of the air
pollution in Taiwan's largest city, Taipei. On average, all commuters in Taipei travel 13.6 km daily, while motorcycle commuters travel 12.2 km. The convenience and mobility of motorcycles makes them
irreplaceable in Taiwan city traffic but they add significantly to air pollution problems. In order to improve air pollution conditions, some
new types of vehicles have been proposed, such as fuel cell driven and
hybrid energy vehicles. In this study, we develop a model pneumatic hybrid motorcycle system and simulate its acceleration and mileage
(km/L) performance. The results show that the pneumatic hybrid
motorcycle can improve efficiency.
Abstract: The paper is concerned with the state examination as
well as the problems during the post surgical (orthopedic)
rehabilitation of the knee and ankle joint. An observation of the
current appliances for a passive rehabilitation devices is presented.
The major necessary and basic features of the intelligent
rehabilitation devices are considered. An approach for a new
intelligent appliance is suggested. The main advantages of the device
are: both active as well as passive rehabilitation of the patient based
on the human - patient reactions and a real time feedback. The basic
components: controller; electrical motor; encoder, force – torque
sensor are discussed in details. The main modes of operation of the
device are considered.
Abstract: Electric vehicle (EV) is one of the effective solutions to
control emission of greenhouses gases in the world. It is of interest
for future transportation due to its sustainability and efficiency by
automotive manufacturers. Various electrical motors have been used
for propulsion system of electric vehicles in last decades. In this
paper brushed DC motor, Induction motor (IM), switched reluctance
motor (SRM) and brushless DC motor (BLDC) are simulated and
compared. BLDC motor is recommended for high performance
electric vehicles. PWM switching technique is implemented for speed
control of BLDC motor. Behavior of different modes of PWM speed
controller of BLDC motor are simulated in MATLAB/SIMULINK.
BLDC motor characteristics are compared and discussed for various
PWM switching modes under normal and inverter fault conditions.
Comparisons and discussions are verified through simulation results.
Abstract: One way for optimum loading of overdimensioning
conveyers is speed (capacity) decrement, with attention for
production capabilities and demands. At conveyers which drives with
three phase slip-ring induction motor, technically reasonable solution
for conveyer (driving motors) speed regulation is using constant
torque subsynchronous cascade with static semiconductor converter
and transformer for energy reversion to the power network. In the
paper is described mathematical model for parameter calculation of
two-motors 6 kV subsynchronous cascade. It is also demonstrated
that applying of this cascade gave several good properties, foremost
in electrical energy saving, also in improving of other energy
indexes, and finally that results in cost reduction of complete
electrical motor drive.
Abstract: Variable speed drives are growing and varying. Drives expanse depend on progress in different part of science like power system, microelectronic, control methods, and so on. Artificial intelligent contains hard computation and soft computation. Artificial intelligent has found high application in most nonlinear systems same as motors drive. Because it has intelligence like human but there are no sentimental against human like angriness and.... Artificial intelligent is used for various points like approximation, control, and monitoring. Because artificial intelligent techniques can use as controller for any system without requirement to system mathematical model, it has been used in electrical drive control. With this manner, efficiency and reliability of drives increase and volume, weight and cost of them decrease.