scholarly journals Straight Gait Research of a Small Electric Hexapod Robot

2021 ◽  
Vol 11 (8) ◽  
pp. 3714
Author(s):  
Feng Zhang ◽  
Shidong Zhang ◽  
Qian Wang ◽  
Yujie Yang ◽  
Bo Jin

Gait is an important research content of hexapod robots. To better improve the motion performance of hexapod robots, many researchers have adopted some high-cost sensors or complex gait control algorithms. This paper studies the straight gait of a small electric hexapod robot with a low cost, which can be used in daily life. The strategy of “increasing duty factor” is put forward in the gait planning, which aims to reduce foot sliding and attitude fluctuation in robot motion. The straight gaits of the robot include tripod gait, quadrangular gait, and pentagonal gait, which can be described conveniently by discretization and a time sequence diagram. In order to facilitate the user to control the robot to achieve all kinds of motion, an online gait transformation algorithm based on the adjustment of foot positions is proposed. In addition, according to the feedback of the actual attitude information, a yaw angle correction algorithm based on kinematics analysis and PD controller is designed to reduce the motion error of the robot. The experiments show that the designed gait planning scheme and control algorithm are effective, and the robot can achieve the expected motion. The RMSE of the row, pitch, and yaw angle was reduced by 35%, 25%, and 12%, respectively, using the “increasing duty factor” strategy, and the yaw angle was limited in the range −3°~3° using the yaw angle correction algorithm. Finally, the comparison with related works and the limitations are discussed.

2021 ◽  
Author(s):  
Junfeng Xue ◽  
Jiehao Li ◽  
Zhihua Chen ◽  
Shoukun Wang ◽  
Junzheng Wang ◽  
...  

2017 ◽  
Vol 17 (07) ◽  
pp. 1740040 ◽  
Author(s):  
HE ZHANG ◽  
RUI WU ◽  
CHANGLE LI ◽  
XIZHE ZANG ◽  
YANHE ZHU ◽  
...  

Multi-legged robots have the ability to traverse rugged terrain and can surmount the obstacles, which are impossible for being overcome by wheeled robots. In this regard, six-legged (hexapod) robots are considered to provide the best combination of adequate adaptability and control complexity. Their motion planning envisages calculating sequences of footsteps and body posture, accounting for the influence of terrain shape, in order to produce the appropriate foot-end trajectory and ensure stable and flexible motion of hexapod robots on the rugged terrain. In this study, a high-order polynomial is used to describe the trajectory model, and a new motion planning theory is proposed, which is aimed at the adaptation of hexapod robots to more complex terrains. An attempt is made to elaborate the adaptive motion planning and perform its experimental verification for a novel hexapod robot HITCR-II, demonstrating its applicability for walking on the unstructured terrain.


Author(s):  
José Luis Viramontes-Reyna ◽  
Josafat Moreno-Silva ◽  
José Guadalupe Montelongo-Sierra ◽  
Erasmo Velazquez-Leyva

This document presents the results obtained from the application of the law of Lens to correctly identify the polarity of the windings in a three-phase motor with 6 exposed terminals, when the corresponding labeling is not in any situation; Prior to identifying the polarity, it should be considered to have the pairs of the three windings located. For the polarity, it is proposed to feed with a voltage of 12 Vrms to one of the windings, which are identified randomly as W1 and W2, where W1 is connected to the voltage phase of 12 Vrms of the signal and W2 to the voltage reference to 0V; by means of voltage induction and considering the law of Lens, the remaining 4 terminals can be identified and labeled as V1, V2, U1 and U2. For this process a microcontroller and control elements with low cost are used.


2020 ◽  
Vol 3 (2) ◽  
pp. 68-81
Author(s):  
Abu Sadath ◽  
Farhana Afroz ◽  
Hosne Ara ◽  
Abdulla-Al Kafy

Rivers are the lifeline of Bangladesh economy and serve as the source of water supply, fisheries, irrigation for agriculture, low-cost transport, generate electricity and conserve biodiversity. The Ichamati River situated in Pabna, Bangladesh is also a blessing for the city. However, recently, due to the irregular and unplanned activities adjacent to the riverside, the life, flow and water quality of the river is in a vulnerable condition. This study aims to identify the present status of the Ichamati River and provide an effective design approach and policy measures in restoring the river flow and control water pollution. The data was collected from the questioner surveys, key informant interviews and focus group discussions. Results suggest that several factors such as the construction of an illegal settlement, unplanned waste dumping, disposal of fiscal sludge through sewerage connection, lack of awareness among people regarding the importance of river biodiversity and absence of riverfront development and conservation plan are responsible for water pollution, inconsistent water flow and damaging the life cycle of Ichamati river. The design approach and policy measures were developed based on the perceptions of local community people, experts and government officials. The suggested policy measures will help to restore the flow of the river and reduce the water pollution, and the design approach will ensure the economic benefit of the riverfront development in future.


2021 ◽  
pp. 096100062110165
Author(s):  
Mohammadhiwa Abdekhoda ◽  
Fatemeh Ranjbaran ◽  
Asghar Sattari

This study was conducted with the aim of evaluating the role of information and information resources in the awareness, control, and prevention of COVID-19. This study was a descriptive-analytical survey in which 450 participants were selected for the study. The data collection instrument was a researcher-made questionnaire. Descriptive and inferential statistics were used to analyze the data through SPSS. The findings show that a wide range of mass media has become well known as information resources for COVID-19. Other findings indicate a significant statistical difference in the rate of using information resources during COVID-19 based on age and gender; however, this difference is not significant regarding the reliability of information resources with regard to age and gender. Health information has an undisputable role in the prevention and control of pandemic diseases such as COVID-19. Providing accurate, reliable, and evidence-based information in a timely manner for the use of resources and information channels related to COVID-19 can be a fast and low-cost strategic approach in confronting this disease.


Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 915
Author(s):  
Gözde Dursun ◽  
Muhammad Umer ◽  
Bernd Markert ◽  
Marcus Stoffel

(1) Background: Bioreactors mimic the natural environment of cells and tissues by providing a controlled micro-environment. However, their design is often expensive and complex. Herein, we have introduced the development of a low-cost compression bioreactor which enables the application of different mechanical stimulation regimes to in vitro tissue models and provides the information of applied stress and strain in real-time. (2) Methods: The compression bioreactor is designed using a mini-computer called Raspberry Pi, which is programmed to apply compressive deformation at various strains and frequencies, as well as to measure the force applied to the tissue constructs. Besides this, we have developed a mobile application connected to the bioreactor software to monitor, command, and control experiments via mobile devices. (3) Results: Cell viability results indicate that the newly designed compression bioreactor supports cell cultivation in a sterile environment without any contamination. The developed bioreactor software plots the experimental data of dynamic mechanical loading in a long-term manner, as well as stores them for further data processing. Following in vitro uniaxial compression conditioning of 3D in vitro cartilage models, chondrocyte cell migration was altered positively compared to static cultures. (4) Conclusion: The developed compression bioreactor can support the in vitro tissue model cultivation and monitor the experimental information with a low-cost controlling system and via mobile application. The highly customizable mold inside the cultivation chamber is a significant approach to solve the limited customization capability of the traditional bioreactors. Most importantly, the compression bioreactor prevents operator- and system-dependent variability between experiments by enabling a dynamic culture in a large volume for multiple numbers of in vitro tissue constructs.


Sensors ◽  
2021 ◽  
Vol 21 (10) ◽  
pp. 3515
Author(s):  
Sung-Ho Sim ◽  
Yoon-Su Jeong

As the development of IoT technologies has progressed rapidly recently, most IoT data are focused on monitoring and control to process IoT data, but the cost of collecting and linking various IoT data increases, requiring the ability to proactively integrate and analyze collected IoT data so that cloud servers (data centers) can process smartly. In this paper, we propose a blockchain-based IoT big data integrity verification technique to ensure the safety of the Third Party Auditor (TPA), which has a role in auditing the integrity of AIoT data. The proposed technique aims to minimize IoT information loss by multiple blockchain groupings of information and signature keys from IoT devices. The proposed technique allows IoT information to be effectively guaranteed the integrity of AIoT data by linking hash values designated as arbitrary, constant-size blocks with previous blocks in hierarchical chains. The proposed technique performs synchronization using location information between the central server and IoT devices to manage the cost of the integrity of IoT information at low cost. In order to easily control a large number of locations of IoT devices, we perform cross-distributed and blockchain linkage processing under constant rules to improve the load and throughput generated by IoT devices.


Sensors ◽  
2021 ◽  
Vol 21 (2) ◽  
pp. 572
Author(s):  
Mads Jochumsen ◽  
Taha Al Muhammadee Janjua ◽  
Juan Carlos Arceo ◽  
Jimmy Lauber ◽  
Emilie Simoneau Buessinger ◽  
...  

Brain-computer interfaces (BCIs) have been proven to be useful for stroke rehabilitation, but there are a number of factors that impede the use of this technology in rehabilitation clinics and in home-use, the major factors including the usability and costs of the BCI system. The aims of this study were to develop a cheap 3D-printed wrist exoskeleton that can be controlled by a cheap open source BCI (OpenViBE), and to determine if training with such a setup could induce neural plasticity. Eleven healthy volunteers imagined wrist extensions, which were detected from single-trial electroencephalography (EEG), and in response to this, the wrist exoskeleton replicated the intended movement. Motor-evoked potentials (MEPs) elicited using transcranial magnetic stimulation were measured before, immediately after, and 30 min after BCI training with the exoskeleton. The BCI system had a true positive rate of 86 ± 12% with 1.20 ± 0.57 false detections per minute. Compared to the measurement before the BCI training, the MEPs increased by 35 ± 60% immediately after and 67 ± 60% 30 min after the BCI training. There was no association between the BCI performance and the induction of plasticity. In conclusion, it is possible to detect imaginary movements using an open-source BCI setup and control a cheap 3D-printed exoskeleton that when combined with the BCI can induce neural plasticity. These findings may promote the availability of BCI technology for rehabilitation clinics and home-use. However, the usability must be improved, and further tests are needed with stroke patients.


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