9,611 research outputs found
Design and motion control of a 6-UPS fully parallel robot for long bone fracture reduction : a thesis presented in partial fulfillment of the requirements for the degree of Master of Engineering in Mechatronics at Massey University
The incidences of long bone fractures in New Zealand are approximately 1 in 10,000. Long bones such as tibia and femur have complicated anatomic structures, making the realignment of these long bone fractures reliant on the skill of the surgeon. The drawbacks of current practice result in long time exposure to radiation, slow recovery and possible morbidity. A semi-automated long bone fracture reduction system based on a 6-DOF parallel robot platform has been in development since 2004. The developed 6-DOF parallel robot platform comprises of six linear actuators with rotary incremental encoders. To implement a realignment of long bone fractures, a framework for the 6-DOF platform robot has been developed. The inverse kinematics and singularity of the 6-DOF parallel robot has been studied to obtain the actions and Jacobin matrices. In motion control a multiple axis motion controller and amplifiers were used for 6-DOF parallel robot. PID tuning algorithms were developed based on the combination of the general tuning result and the contour control principle. The PID parameters have been validated by a number of experiments. The practical realignment of bone fractures requires a "Pull-Rotate-Push" action implemented by the 6-DOF parallel robot. After calibration, the reduction trajectories were generated accurately. The actual trials on the artificial fractures have shown that the robot developed is capable of performing the required reduction motion
High-performance control of dual-inertia servo-drive systems using low-cost integrated SAW torque transducers
Abstract—This paper provides a systematic comparative
study of compensation schemes for the coordinated motion
control of two-inertia mechanical systems. Specifically, classical proportional–integral (PI), proportional–integral–derivative (PID), and resonance ratio control (RRC) are considered, with an enhanced structure based on RRC, termed RRC+, being proposed. Motor-side and load-side dynamics for each control structure are identified, with the “integral of time multiplied by absolute
error” performance index being employed as a benchmark metric. PID and RRC control schemes are shown to be identical from a closed-loop perspective, albeit employing different feedback sensing mechanisms. A qualitative study of the practical effects of employing each methodology shows that RRC-type structures
provide preferred solutions if low-cost high-performance torque transducers can be employed, for instance, those based on surface acoustic wave tecnologies. Moreover, the extra degree of freedom afforded by both PID and RRC, as compared with the basic PI, is shown to be sufficient to simultaneously induce optimal closed-loop performance and independent selection of virtual inertia ratio. Furthermore, the proposed RRC+ scheme is subsequently
shown to additionally facilitate independent assignment
of closed-loop bandwidth. Summary attributes of the investigation are validated by both simulation studies and by realization of the methodologies for control of a custom-designed two-inertia system
Observer-based tuning of two-inertia servo-drive systems with integrated SAW torque transducers
This paper proposes controller design and tuning
methodologies that facilitate the rejection of periodic load-side disturbances applied to a torsional mechanical system while simultaneously compensating for the observer’s inherent phase delay. This facilitates the use of lower-bandwidth practically realizable disturbance observers. The merits of implementing full- and reduced-order observers are investigated, with the latter being implemented with a new low-cost servo-machine-integrated highband width
torque-sensing device based on surface acoustic wave
(SAW) technology. Specifically, the authors’ previous work based on proportional–integral–derivative (PID) and resonance ratio control (RRC) controllers (IEEE Trans. Ind. Electron., vol. 53, no. 4, pp. 1226–1237, Aug. 2006) is augmented with observer disturbance feedback. It is shown that higher-bandwidth disturbance observers are required to maximize disturbance attenuation over the low-frequency band (as well as the desired rejection frequency), thereby attenuating a wide range of possible frequencies. In such cases, therefore, it is shown that the RRC controller is
the preferred solution since it can employ significantly higher observer bandwidth, when compared to PID counterparts, by virtue of reduced noise sensitivity. Furthermore, it is demonstrated that the prototype servo-machine-integrated 20-N · mSAWtorque transducer is not unduly affected by machine-generated electromagnetic
noise and exhibits similar dynamic behavior as a
conventional instrument inline torque transducer
Development Of A Semi-Swath Craft For Malaysian Waters
Small Waterplane Area Twin Hull (SWATH) and Catamaran vessels are known to have more stable platform as compared to mono-hulls. A further advantage of SWATH as compared to Catamaran is its smaller waterplane area that provides
better seakeeping qualities. However, the significant drawback of the SWATH vessel is when encountering head-sea at high forward speed. Due to its low stiffness, it has
a tendency for large pitch motions. Consequently, this may lead to excessive trim or even deck wetness. This phenomenon will not only degrade the comfortability but
also results in structural damage with greater safety risks. In this research a modified SWATH design is proposed. The proposed design concept represents a combination of Catamaran and SWATH vessel hull features that will lead to reduce in bow-diving but still maintains good seakeeping capabilities. This is then called the Semi-
SWATH vessel. In addition, the full-design of this vessel has been equipped by fixed fore fins and controllable aft fins attached on each lower hull. In the development of
controllable aft fins, the PID controller system was applied to obtain an optimal vessel’s ride performance at speeds of 15 (medium) and 20 (high) knots. In this research work, the seakeeping performance of Semi-SWATH vessel was evaluated using time-domain simulation approach. The effect of fin stabilizer on the
bare hull performance is considered. The validity of numerical evaluation was then compared with model experiments carried out in the Towing Tank at Marine
Technology Laboratory, UTM. It is shown that the Semi-SWATH vessel with controllable fin stabilizer can have significantly reduction by about 42.57% of heave
motion and 48.80% of pitch motion
No More Differentiator in PID:Development of Nonlinear Lead for Precision Mechatronics
Industrial PID consists of three elements: Lag (integrator), Lead
(Differentiator) and Low Pass Filters (LPF). PID being a linear control method
is inherently bounded by the waterbed effect due to which there exists a
trade-off between precision \& tracking, provided by Lag and LPF on one side
and stability \& robustness, provided by Lead on the other side. Nonlinear
reset strategies applied in Lag and LPF elements have been very effective in
reducing this trade-off. However, there is lack of study in developing a reset
Lead element. In this paper, we develop a novel lead element which provides
higher precision and stability compared to the linear lead filter and can be
used as a replacement for the same. The concept is presented and validated on a
Lorentz-actuated nanometer precision stage. Improvements in precision, tracking
and bandwidth are shown through two separate designs. Performance is validated
in both time and frequency domain to ensure that phase margin achieved on the
practical setup matches design theories.Comment: European Control Conference 201
Inverted Pendulum Human Transporter Balance Control System Based on Proportional Integral Derivative – Active Force Control
Many research for the balancing of inverted pendulum
control system to develop the performance. This paper
will simulate a Proportional Integral Derivative – Active
Force Control (PID-ACF) methods to swing a pendulum
attached to a cart from an initial downwards position to
an upright position and keep that condition stable and
implemented to the segway chair human transporter. The
combined control between PID and AFC system is used
to maintain the actual acceleration is affected by
disruption of the references given, because external
disturbance can affect the system. For the experimental
it will compare the performance between using a
classical control PID and PID-AFC
Understanding and Design of an Arduino-based PID Controller
This thesis presents research and design of a Proportional, Integral, and Derivative (PID) controller that uses a microcontroller (Arduino) platform. The research part discusses the structure of a PID algorithm with some motivating work already performed with the Arduino-based PID controller from various fields. An inexpensive Arduino-based PID controller designed in the laboratory to control the temperature, consists of hardware parts: Arduino UNO, thermoelectric cooler, and electronic components while the software portion includes C/C++ programming. The PID parameters for a particular controller are found manually. The role of different PID parameters is discussed with the subsequent comparison between different modes of PID controllers. The designed system can effectively measure the temperature with an error of ± 0.6℃ while a stable temperature control with only slight deviation from the desired value (setpoint) is achieved. The designed system and concepts learned from the control system serve in pursuing inexpensive and precise ways to control physical parameters within a desired range in our laboratory
Inverted Pendulum Human Transporter Balance Control System Based on Proportional Integral Derivative – Active Force Control
Many research for the balancing of inverted pendulum control system to develop the performance. This paper will simulate a Proportional Integral Derivative – Active Force Control (PID-ACF) methods to swing a pendulum attached to a cart from an initial downwards position to an upright position and keep that condition stable and implemented to the segway chair human transporter. The combined control between PID and AFC system is used to maintain the actual acceleration is affected by disruption of the references given, because external disturbance can affect the system. For the experimental it will compare the performance between using a classical control PID and PID-AFC.
Keywords: inverted pendulum, Active Force Control, segway
Beyond the Waterbed Effect: Development of Fractional Order CRONE Control with Non-Linear Reset
In this paper a novel reset control synthesis method is proposed: CRONE reset
control, combining a robust fractional CRONE controller with non-linear reset
control to overcome waterbed effect. In CRONE control, robustness is achieved
by creation of constant phase behaviour around bandwidth with the use of
fractional operators, also allowing more freedom in shaping the open-loop
frequency response. However, being a linear controller it suffers from the
inevitable trade-off between robustness and performance as a result of the
waterbed effect. Here reset control is introduced in the CRONE design to
overcome the fundamental limitations. In the new controller design, reset phase
advantage is approximated using describing function analysis and used to
achieve better open-loop shape. Sufficient quadratic stability conditions are
shown for the designed CRONE reset controllers and the control design is
validated on a Lorentz-actuated nanometre precision stage. It is shown that for
similar phase margin, better performance in terms of reference-tracking and
noise attenuation can be achieved.Comment: American Control Conference 201
- …