1,721,018 research outputs found
Force and impedance control for hydraulically driven hexapod robot walking on uneven terrain
Full text linkA variety approach of multi-legged robot designs, especially on a large scale design with hydraulically driven actuators exist, but most of it still unsolved and used primitive techniques on control solutions. This made this area of research still far from demonstrating the scientific solutions, which is more towards developing and optimizing the algorithm, control technique and software engineering for practical locomotion (flexibility and reliability). Therefore in this thesis,the study is done to propose two categories of solution for statically stable and hydraulically driven hexapod robot, named COMET-IV, which are dynamic walking trajectory generation and force/impedance control implementation (during body start patching), in order to solve the stability problems (horizontal) that encountered when walking on extremely uneven terrains.Only three sensors are used for control feedback; potentiometers (each leg joint), pressure
sensors (hydraulic cylinders) and attitude sensor (center of body). For dynamic walking trajectory generation, the fixed/determined of tripod walking trajectory is modified with force threshold-based, named as environment trailed trajectory (ETT),on each first step of foot during
support phase (preliminary sensing uneven terrain surfaces). Moreover,the proposed dynamic trajectory generation is then upgraded with capability of omni-directional walking with a
proposed center of body rotational-based method.
The instability of using the ETT module alone and with proposed hybrid force/position control in the previous progress, during body patching on walking session is then solved using the proposed pull-back position-based force control (PPF). PPF controller is derived from the ETT
module itself and supported by proposed compliant (switching) mechanism, logical attitude control and dynamic swing rising control. The limitation of PPF controller applied with ETT module for walking on uneven terrain contains extreme soft surface makes the study narrowed to
the impedance control approaches as a replacement of PPF controller. Three new adaptive impedance controller are designed and proposed: Optimal single leg impedance control based on body inertia, Optimal center of mass—based impedance control based on body inertia and Single
leg impedance control with self-tuning stiffness. To reduce the hard swinging/shaking of the robot's body in motion that arise after applying the proposed impedance controllers, fuzzy logic control via Takagaki-Sugeno-Kang (TSK) model is proposed to be cascaded on the input feedback of the controller.The study has verified the effectiveness of both categories of control unit (dynamic trajectory,force controller and impedance controllers) combination throughout several experiments of COMET-IV walking on uneven/unstructured terrains
Identification and Characteristics of Parallel Actuation Robot’s Leg Configuration Using Hammerstein-Wiener Approach
Full text linkThis paper presents the modeling of a leg of Quadruped with Parallel Actuation Leg (QPAL) robot. QPAL leg designed with 3 Degree of Freedom (DOF) configuration with indirect or parallel actuation for each joint mimicking a muscle of life form creature such as insect and bugs classified into shoulder, thigh and shank parts. Indirect actuation configuration on its leg makes this robot has different perspective on joint rotational drive and control. Therefore, this project has taken initiative to identify and modeling this indirect actuation joint by using system identification (SI) in order to obtain a mathematical model of each joint of QPAL robot’s leg. A system identification approach was implemented by employing a Hammerstein-Wiener (HW) model as model structure. The state-space model and the transfer function are designed and generated using Hammerstein-wiener modeling procedures start with experiment setup and data collection from experiment. Continue with data processing, selecting model structure, estimation and validation of the model using system SI toolbox in MATLAB®. The best percentage fits for Joint 1, Joint 2 and Joint 3 are 71.06%, 79.14% and 71.35% respectively, meaning that the estimated model is almost tracking the real output data from the experiments. The model for Joint 1 is ideally acceptable and highly applicable since the correlation curves lie between the confidence interval. While the model for Joint 2 and Joint 3 are considered well and acceptable as the correlation curves are almost lies between the confidence interval. The balances 28.94%, 20.86%, and 28.65% are losses due to nonlinear factor such as friction, backlash, torque, and external disturbance
Proceeding of Colloquium on Robotics, Unmanned Systems and Cybernetics 2014
Full text linkColloquium on Robotics, Unmanned Systems and Cybernetics 2014 (CRUSC 2014) is one of the initiatives from Robotics and Unmanned System (RUS) research group under the
Instrumentation and Control Engineering (iCE) Cluster,
Faculty of Electrical & Electronics Engineering, Universiti Malaysia Pahang (UMP) to bring together the researchers that related to the field of robotics, unmanned systems and cybernetics. In this first CRUS event the targeted is to bring majority participants among the undergraduates
and postgraduate under related research/focus group to
submit research papers, concept papers, technical report or
undergraduate final year project report
PD-like FLC with Admittance Control of Hexapod Robot’s Leg Vertical Positioning for Seabed Locomotion
Full text linkThis paper presents a proposed Proportional and
Derivative (PD)-like Fuzzy Logic Control (FLC) (PD-FLC) on
dynamic control for vertical positioning of Hexapod Robot
walking on seabed environment. The study has been carried out
by modeling the buoyancy force following the restoration force to
achieve the drowning level according to the Archimedes’
principle. The restoration force need to be positive in order to
ensure robot locomotion is not affected by buoyancy factor. As
for this force control solution, PD-FLC is used and integrated
with admittance control that based on the total of force of foot
placement by considering Center of Mass (CoM) of the robot
during walking period. This integrated control technique is
design and verify on the real-time based 4 degree of freedom
(DoF) leg configuration of hexapod robot model. The scope of
analysis is focus on walking on the varied stiffness of undersea
bottom soil with tripod walking pattern. Moreover the
verification is done on the vertical foot motion of the leg and the
body mass coordination movement during walking period. The
results shows that proposed PD-FLC admittance control able to
cater the force restoration factor by making vertical force on
each foot bigger enough (sufficient foot placement) if compare to
the buoyancy force of the ocean, thus performing stable tripod
walking on the seabed with uncertain stiffness
CFD Analysis for Rigid Moving Body at the High Tidal Environment of Sea-bed
Full text linkIn this paper, the basic hydrodynamic theories have been used to find the hydrodynamic factors for the underwater moving rectangular body as considered the shape of underwater walking robot. The added-mass, wave drag and lift coefficients are determined using a frequency-domain, simple-source based boundary integral method. In this paper, the hydrodynamics added mass and drag forces will be determined theoretically calculation the Reynolds number is measured in order to understand the type of water flow over the structure. The relative velocity vectors, Reynolds number, drag and lift forces for each state of motion is obtained in both static water condition and in ocean current condition. Results are obtained for a range of wave frequencies and depths of the underwater robotic body submerged all for a fixed water depth of 50-100 m. With the wave exciting force and moment determined using the Navier-Stokes theory. The computational study is to determine body-shape effects on the incident and radiated wave forces and subsequently the motion response. This study and results further implemented to modern adaptive drag force model-based controller in horizontal flow disturbance control for underwater multilegged or wheeled robot
Combination of Transverse-Trot Gait Pattern for Quadruped Walking Robot
Full text linkThis paper presents a combination of transverse and trot walking pattern technique for hexa-quad robot after transformation to optimize the multi-legged robot operation and walking performances. Due to the limitation on the stability of hexapod robot, the combination of hexa-quad walking sequence is proposed to stabilize the quadruped configuration and walking modes. Quadruped robot configuration is stand within dynamically and statically stable criteria if compare to the hexapod robot that has only statically stable criteria. Thus, it is very crucial to have a stable walking sequence technique during walking and operation session. Therefore walking sequence technique to perform for hexa-quad transformation is proposed based on robot’s Center of mass (CoM) and defined support polygon on positioning the leg in transformation process. A real-time based model of hexapod robot control architecture with proposed walking sequence is designed and validated using separated 3 dimensional (3D) simulators. The analysis of robot stepping foot motion is done to verify the desire
designed walking sequences and the Body Mass Coordinate (BMC) is analyzed for way point of robot walking
PD-FLC with Admittance Control for Hexapod Robot's Leg Positioning on Seabed
Full text linkThis paper presents a proposed Proportional and Derivative (PD)-like Fuzzy Logic Control (FLC) (PD-FLC) on dynamic control for vertical positioning of Hexapod Robot walking on seabed environment. The study has been carried out by modelling the buoyancy force following the restoration force to achieve the drowning level according to Archimedes' principle. The restoration force need to be positive in order to ensure robot locomotion is not affected by buoyancy factor. As a solution to control this force, PD-FLC is used and integrated with admittance control that is based on the total force acting on foot placement by considering Center of Mass (CoM) of the robot during walking period. The integrated control technique is verified on a real-time based 4 degree of freedom (DoF) leg configuration of hexapod robot model. The scope of analysis is focused on walking on the varying stiffness of undersea bottom soil with tripod walking pattern. Moreover, the verification is done on the vertical foot motion of the leg and the body mass coordination movement during walking period. The results show that the proposed PD-FLC admittance control is able to cater the force restoration factor by making the vertical force on each foot sufficiently big (sufficient foot placement) compared to the buoyancy force of the ocean, thus resulting in stable tripod walking on the seabed with uncertain stiffness
Adaptive Impedance Control Based on CoM for Hexapod Robot Walking on the Bottom of Ocean
Full text linkThis paper presents a proposed adaptive impedance control that derived based on Center of Mass (CoM) of the hexapod robot for walking on the bottom of water or seabed. The study has been carried out by modeling the buoyancy force following the restoration force to a
chieve the drowning level according to the Archimedes’ principle. The restoration force need to be positive in order to ensure robot locomotion is not affected by buoyancy factor. As for this force control solution, impedance control has been derived based on the total of for ce of foot placement to consider CoM of the robot during walking period. This derived impedance control is design for the real-time based 4 degree of freedom (DoF)
leg configuration of hexapod robot model. The scope of analysis is focus on walking on the varied stiffness of undersea bottom soil with tripod walking pattern. The verification is done on the vertical foot motion of the leg and the body mass coordination movement during walking period. The results shows that proposed impedance control able to control the force restoration factor by making vertical force on each foot bigger enough (sufficient foot placement) if compare to the buoyancy force of the ocean, thus performing stable tripod walking on the seabed with uncertain stiffness
Improving pressure valve precision using finite-time prescribed performance with fractional-order proportional, integral and derivative control
Full text linkThe paper presents the improvement of precision control on pneumatic system pressure using Finite-time Prescribed Performance Control with the Fractional-Order Proportional, Integral, and Derivative (FOPID-FTPPC) control. The control strategy is proposed to overcome the nonlinearity produced by the pneumatic system in regulating the pressure on positioning operation. The study was conducted through several experiments with a 5/3-way pneumatic proportional valve that configured with pressure transducers as feedback responses. The study was done with two different types of common input trajectories: step and sinusoidal inputs. The proposed FOPIDFTPPC controller outperforms the FOPID controller by 26% in terms of minimizing the overshoot of the step input trajectory. On the other hand, the proposed controller exhibits significant performance with a sine wave input trajectory, and the advantage of its integration with FTCPPC frameworks allows it to achieve steady state performance even more quickly. The findings demonstrate that the proposed the proposed FOPID-FTPPC controller can regulate the pneumatic systems pressures while eliminating steady-state errors, fast response as well as reducing the overshoot
QoS Forwarding on the Optical Internet Backbone Area Using R-IWDMTC Protocol
Full text linkThis article describes the study of improving the proposed protocol called Receiverinitiated WDM Tree Construction (R-IWDMTC) protocol. The protocol has been introduced by
Salvador et al. (Extended via Multi-protocol Label Switching (MPLS)) provides connection-oriented setup
and multicast tree construction control for Optical Internet data forwarding in the network backbone area. The study has done several analysis and research to improve R-IWDMTC protocol to support quality and services (QoS) (differentiation and integration services). Several algorithms, schemes and techniques have been suggested in this study including several analyses. The study has focused on RTA link set-up and data forwarding. Discrete event simulator called OMNeT++ is used for modelling and analysis purposes and model of optical internet backbone area has been developed. The analysis were referred from
the average access delay, percentage of loses, jitters
and throughput of data (video, voice and text) that has
been transferred between two end point via optical
internet backbone area. The results were proved that
the differentiation and integration technique could be
applied in Optical Internet and gateway system by
using R-IWDMTC protocol
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