78 research outputs found
Forward Kinematics Based Prediction for Bending Motion of Soft Pneumatic Actuators with Various Air Chambers
This study proposes a forward kinematic model for soft actuators that utilize pneumatic control to predict their bending motion, which is simulated using Ansys software. Firstly, a bending motion test is conducted with a 2-air chamber actuator to derive an equation that establishes the relationship between the bending angle and input pressure. Next, a serial model for the overall soft actuator is developed using forward kinematics with the DH method. The angle variables in the soft actuator are then replaced with an equation that relates the deformed angle and compressed air. Finally, the proposed serial model is used to predict the bending motion of 4-air and 6-air chamber actuators, and the results are compared to simulations and real experiments. The comparison shows that the proposed model could accurately predict the bending motion of the real actuators within an acceptable tolerance of 10%
Design and development of a delta robot system to classify objects using image processing
In this paper, a delta robot is designed to grasp objects in an automatic sorting system. The system consists of a delta robot arm for grasping objects, a belt conveyor for transmitting objects, a camera mounted above the conveyor to capture images of objects, and a computer for processing images to classify objects. The delta robot is driven by three direct current (DC) servo motors. The controller is implemented by an Arduino board and Raspberry Pi 4 computer. The Arduino is programmed to provide rotation to each corresponding motor. The Raspberry Pi 4 computer is used to process images of objects to classify objects according to their color. An image processing algorithm is developed to classify objects by color. The blue, green, red (BGR) image of objects is converted to HSV color space and then different thresholds are applied to recognize the object’s color. The robot grasps objects and put them in the correct position according to information received from Raspberry. Experimental results show that the accuracy when classifying red and yellow objects is 100%, and for green objects is 97.5%. The system takes an average of 1.8 s to sort an object
Development of Multi-Robotic Arm System for Sorting System Using Computer Vision
This paper develops a multi-robotic arm system and a stereo vision system to sort objects in the right position according to size and shape attributes. The robotic arm system consists of one master and three slave robots associated with three conveyor belts. Each robotic arm is controlled by a robot controller based on a microcontroller. A master controller is used for the vision system and communicating with slave robotic arms using the Modbus RTU protocol through an RS485 serial interface. The stereo vision system is built to determine the 3D coordinates of the object. Instead of rebuilding the entire disparity map, which is computationally expensive, the centroids of the objects in the two images are calculated to determine the depth value. After that, we can calculate the 3D coordinates of the object by using the formula of the pinhole camera model. Objects are picked up and placed on a conveyor branch according to their shape. The conveyor transports the object to the location of the slave robot. Based on the size attribute that the slave robot receives from the master, the object is picked and placed in the right position. Experiment results reveal the effectiveness of the system. The system can be used in industrial processes to reduce the required time and improve the performance of the production line
Forward Kinematics Based Prediction for Bending Motion of Soft Pneumatic Actuators with Various Air Chambers
This study proposes a forward kinematic model for soft actuators that utilize pneumatic control to predict their bending motion, which is simulated using Ansys software. Firstly, a bending motion test is conducted with a 2-air chamber actuator to derive an equation that establishes the relationship between the bending angle and input pressure. Next, a serial model for the overall soft actuator is developed using forward kinematics with the DH method. The angle variables in the soft actuator are then replaced with an equation that relates the deformed angle and compressed air. Finally, the proposed serial model is used to predict the bending motion of 4-air and 6-air chamber actuators, and the results are compared to simulations and real experiments. The comparison shows that the proposed model could accurately predict the bending motion of the real actuators within an acceptable tolerance of 10%
An approach for linguistic multi-attribute decision making based on linguistic many-valued logic
There are various types of multi-attribute decision-making (MADM) problems in our daily lives and decision-making problems under uncertain environments with vague and imprecise information involved. Therefore, linguistic multi-attribute decision-making problems are an important type studied extensively. Besides, it is easier for decision-makers to use linguistic terms to evaluate/choose among alternatives in real life. Based on the theoretical foundation of the Hedge algebra and linguistic many-valued logic, this study aims to address multi-attribute decision-making problems by linguistic valued qualitative aggregation and reasoning method. In this paper, we construct a finite monotonous Hedge algebra for modeling the linguistic information related to MADM problems and use linguistic many-valued logic for deducing the outcome of decision making. Our method computes directly on linguistic terms without numerical approximation. This method takes advantage of linguistic information processing and shows the benefit of Hedge algebra
Assessing local people’s satisfaction on resettlement arrangements of A Luoi Hydropower project, Thua Thien Hue Province
This study aims to estimate the level of satisfaction about resettlement arrangements for local people who have been affected by A Luoi hydroelectric construction project in the Thua Thien Hue province. This research used the Likert scale method to assess the satisfaction level of 98 households living in two of the resettlement sites. Results illustrate that there is variations in the level of satisfaction of local people in the two resettlement sites, Hong Thuong and Hong Ha. In the resettlement area (RA) of the Hong Thuong Commune, people are dissatisfied with the location arrangement. There is a lack of quality in the houses built, been damaged, cracked and degraded, since the construction design is not appropriate for the customs and practices of local people, with a satisfaction rating of 1.07. Meanwhile, at the resettlement site of the Hong Ha commune, people felt satisfied with the arrangement site of the RA and allocated residential land area with the satisfaction rating of 4.19. Our results will help the government, as well as the project owners, to understand the points of dissatisfaction of local people in order to have accordant solutions, ensuring the stable life for local people in those settlement areas.Nghiên cứu này nhằm mục đích đánh giá được mức độ hài lòng của người dân về việc bố trí tái định cư (TĐC) cho người dân bị ảnh hưởng bởi dự án xây dựng thuỷ điện A Lưới, tỉnh Thừa Thiên Huế. Nghiên cứu đã sử dụng phương pháp thang đo Likert để đánh giá mức độ hài lòng của 98 hộ dân sống tại hai khu tái định cư Hồng Thượng và Hồng Hạ. Kết quả nghiên cứu đã cho thấy có sự khác nhau về mức độ hài lòng của người dân tại hai khu TĐC. Tại khu TĐC Hồng Thượng người dân thấy không hài lòng về địa điểm bố trí TĐC, nhà ở được xây dựng thiếu chất lượng đã bị hư hỏng, nứt nẻ xuống cấp, thiết kế xây dựng không phù hợp với phong tục, tập quán của người dân địa phương, với chỉ số đánh giá hài lòng là 1,07. Trong khi đó, tại khu TĐC xã Hồng Hạ người dân lại thấy hài lòng về điểm bố trí TĐC và diện tích đất ở được cấp, với chỉ số đánh giá hài lòng là 4,19. Kết quả nghiên cứu của đề tài sẽ giúp cho chính quyền cũng như chủ đầu tư dự án nắm rõ những điểm không hài lòng của người dân để có hướng giải quyết phù hợp nhằm đảm bảo cuộc sống ổn định cho người dân tại nơi tái định cư
Design a low-cost delta robot arm for pick and place applications based on computer vision
In this paper, we develop a low-cost delta robot arm for grasping objects of unspecified size thanks to a vision system. Stepper motors are used instead of ac servo motors to build a low-cost delta robot arm. Furthermore, we use available materials and machining methods such as laser cutting and 3d printing instead of CNC milling and turning to reduce fabrication costs. The controller is based on a low-cost embedded controller - Arduino Uno for controlling the robot's motion. The vision system is constructed to determine the 3D coordinate of objects in the workspace as well as the sizes of objects. The gripper is opened with a distance of two fingers equal to the size of the objects, and the robot is controlled to the objects' coordinates to grasp them. An application to pick up objects on a conveyor belt is developed to validate the design. The experimental results show that the robot system works correctly, the robot arm moves smoothly, and the information determined by the vision system has a small error, ensuring that the robot can accurately pick up products
12CO emission from EP Aqr: Another example of an axi-symmetric AGB wind?
The CO(1-0) and (2-1) emission of the circumstellar envelope of the AGB star
EP Aqr has been observed using the IRAM PdBI and the IRAM 30-m telescope. The
line profiles reveal the presence of two distinct components centered on the
star velocity, a broad component extending up to ~10 km/s and a narrow
component indicating an expansion velocity of ~2 km/s. An early analysis of
these data was performed under the assumption of isotropic winds. The present
study revisits this interpretation by assuming instead a bipolar outflow nearly
aligned with the line of sight. A satisfactory description of the observed flux
densities is obtained with a radial expansion velocity increasing from ~2 km/s
at the equator to ~10 km/s near the poles. The angular aperture of the bipolar
outflow is ~45 deg with respect to the star axis, which makes an angle of ~13
deg with the line of sight. A detailed study of the CO(1-0) to CO(2-1) flux
ratio reveals a significant dependence of the temperature on the star latitude,
smaller and steeper at the poles than at the equator at large distances from
the star. Under the hypothesis of radial expansion and of rotation invariance
about the star axis, the effective density has been evaluated in space as a
function of star coordinates. Evidence is found for an enhancement of the
effective density in the northern hemisphere of the star at angular distances
in excess of ~3" and covering the whole longitudinal range. The peak velocity
of the narrow component is observed to vary slightly with position on the sky,
a variation consistent with the model and understood as the effect of the
inclination of the star axis with respect to the line of sight. While the
phenomenological model presented here reproduces well the general features of
the observations, significant differences are also revealed, which would
require a better spatial resolution to be properly described.Comment: accepted for publication in Astronomy & Astrophysic
The morpho-kinematics of the circumstellar envelope around the AGB star EP Aqr
ALMA observations of CO(1-0) and CO(2-1) emissions of the circumstellar
envelope of EP Aqr, an oxygen-rich AGB star, are reported. A thorough analysis
of their properties is presented using an original method based on the
separation of the data-cube into a low velocity component associated with an
equatorial outflow and a faster component associated with a bipolar outflow. A
number of important and new results are obtained concerning the distribution in
space of the effective emissivity, the temperature, the density and the flux of
matter. A mass loss rate of (1.60.4)10 solar masses per year is
measured. The main parameters defining the morphology and kinematics of the
envelope are evaluated and uncertainties inherent to de-projection are
critically discussed. Detailed properties of the equatorial region of the
envelope are presented including a measurement of the line width and a precise
description of the observed inhomogeneity of both morphology and kinematics. In
particular, in addition to the presence of a previously observed spiral
enhancement of the morphology at very small Doppler velocities, a similarly
significant but uncorrelated circular enhancement of the expansion velocity is
revealed, both close to the limit of sensitivity. The results of the analysis
place significant constraints on the parameters of models proposing
descriptions of the mass loss mechanism, but cannot choose among them with
confidence.Comment: 26 pages, 31 figures, accepted for publication in MNRA
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