scholarly journals A compliant control method for robust trot motion of hydraulic actuated quadruped robot

2018 ◽  
Vol 15 (6) ◽  
pp. 172988141881323 ◽  
Author(s):  
Teng Chen ◽  
Xuewen Rong ◽  
Yibin Li ◽  
Chao Ding ◽  
Hui Chai ◽  
...  
Keyword(s):  
Motion Control ◽  
Control Method ◽  
Middle Layer ◽  
Bottom Layer ◽  
Hydraulic Cylinder ◽  
Simulation Software ◽  
Lateral Impact ◽  
Software Environment ◽  
Control Approach ◽  
Active Compliance

A motion control approach is proposed for hydraulic actuated quadruped robots, aiming to achieve active compliance and robust motion control. The approach is designed with a structure of three layers. Servo valve-controlled asymmetric hydraulic cylinder model is established to obtain the relationship between the desired torque and the control current signal, which is the bottom layer. The middle layer is based on the virtual model of the leg for active compliance. The upper layer considers the torso posture and velocity into planning the foot trajectories based on the spring loaded inverted pendulum model. Trotting gait simulations are conducted based on the proposed framework in the simulation software environment Webots. The motion control approach has been implemented on a robot prototype SCalf-II (SDU calf), where experiments have been conducted including omnidirectional trotting gait, lateral impact recovery and climbing slopes. The experiments demonstrate that the proposed approach can effectively control the hydraulic actuated robots.

DUTY-CYCLED SPINNING BASED 3D MOTION CONTROL APPROACH FOR BEVEL-TIPPED FLEXIBLE NEEDLE INSERTION

2018 ◽  
Vol 18 (07) ◽  
pp. 1840017 ◽  
Author(s):  
QIN YAO ◽  
XUMING ZHANG
Keyword(s):  
Motion Control ◽  
Control Method ◽  
Tracking Error ◽  
Open Loop ◽  
Loop Control ◽  
3D Motion ◽  
Control Approach ◽  
Target Error ◽  
The Mean ◽  
Simulation Results

Flexible needle has been widely used in the therapy delivery because it can advance along the curved lines to avoid the obstacles like important organs and bones. However, most control algorithms for the flexible needle are still limited to address its motion along a set of arcs in the two-dimensional (2D) plane. To resolve this problem, this paper has proposed an improved duty-cycled spinning based three-dimensional (3D) motion control approach to ensure that the beveled-tip flexible needle can track a desired trajectory to reach the target within the tissue. Compared with the existing open-loop duty-cycled spinning method which is limited to tracking 2D trajectory comprised of few arcs, the proposed closed-loop control method can be used for tracking any 3D trajectory comprised of numerous arcs. Distinctively, the proposed method is independent of the tissue parameters and robust to such disturbances as tissue deformation. In the trajectory tracking simulation, the designed controller is tested on the helical trajectory, the trajectory generated by rapidly-exploring random tree (RRT) algorithm and the helical trajectory. The simulation results show that the mean tracking error and the target error are less than 0.02[Formula: see text]mm for the former two kinds of trajectories. In the case of tracking the helical trajectory, the mean tracking error target error is less than 0.5[Formula: see text]mm and 1.5[Formula: see text]mm, respectively. The simulation results prove the effectiveness of the proposed method.

scholarly journals Structural Design and Material Cutting Using a Laser End Effector on a Robot Arm

TEM Journal ◽  
2020 ◽  
pp. 1455-1459
Author(s):  
Martin Pollák ◽  
Jozef Dobránsky
Keyword(s):  
Structural Design ◽  
Robot Control ◽  
Control Method ◽  
Control Program ◽  
Soft Materials ◽  
Electrical Circuit ◽  
Simulation Software ◽  
Robot Arm ◽  
Software Environment ◽  
End Effector

The paper deals with the structural design of a laser end effector for the arm of the ABB IRB 140 robot which makes products by the laser cutting technology involving soft materials, such as e.g. paper, wood and others. A laser with a power of 1 W was chosen to carry out the cutting. An electrical circuit with a power supply was created for the selected laser; a control method and a structural design of the jig to be attached to the flange of the robot arm were proposed. Subsequently, the robot control program was connected to the control via a computer and the RoboDK simulation software. The paper describes in more detail the creation of the robot control program and the simulation designed in the simulation software environment, as well as the programming of laser control scripts in Python and in the programming environment of Arduino microcontroller.

Man-machine interaction-based motion control of a robotic walker

2020 ◽  
pp. 1-21
Author(s):  
Chengjie Zhang ◽  
Shuai Guo ◽  
Fengfeng (Jeff) Xi
Keyword(s):  
Motion Control ◽  
Control Method ◽  
Fuzzy Controller ◽  
Gait Training ◽  
Recognition Algorithm ◽  
Simulated Patients ◽  
Acceptable Error ◽  
Control Approach ◽  
Robotic Walker ◽  
Force Signal

BACKGROUND: The aging population brings the problem of healthcare and dyskinesia. The lack of mobility extremely affects stroke patient’s activities of daily living (ADL) and decreases their quality of life. To assist these mobility-limited people, a robotic walker is designed to facilitate gait rehabilitation training. OBJECTIVE: The aim of this paper is to present the implementation of a novel motion control method to assist disabled people based on their motion intention. METHODS: The kinematic framework of the robotic walker is outlined. We propose an intention recognition algorithm based on the interactive force signal. A novel motion control method combined with T-S fuzzy controller and PD controller is proposed. The motion controller can recognize the intention of the user through the interactive force, which allows the user to move or turn around as usual, instead of using their hands to control the walker. RESULTS: Preliminary experiments with healthy individuals and simulated patients are carried out to verify the effectiveness of the algorithm. The results show that the proposed motion control approach can recognize the user’s intention, is easy to control and has a higher precision than the traditional proportional–integral–derivative controller. CONCLUSION: The results show that users could achieve the task with acceptable error, which indicates the potential of the proposed control method for gait training.

scholarly journals A Novel Compound Control Method for Hydraulically Driven Shearer Drum Lifting

2014 ◽  
Vol 2014 ◽  
pp. 1-12 ◽  
Author(s):  
Lei Si ◽  
Zhongbin Wang ◽  
Xinhua Liu ◽  
Lin Zhang
Keyword(s):  
Control Method ◽  
Rbf Neural Network ◽  
Response Speed ◽  
Hydraulic Cylinder ◽  
Control Approach ◽  
Tuning Parameters ◽  
Compound Control ◽  
Control Precision ◽  
Asymmetrical Hydraulic Cylinder ◽  
Fractional Order Pid

In order to adjust shearer drum swiftly and precisely to adapt to the changes of coal seam, a compound control approach based on cerebellar model articulation control and fractional order PID controller was proposed. As the movement precision and response speed of hydraulic system were determined mainly by the control precision of valve-controlled asymmetrical hydraulic cylinder, its working principle and characteristics were analyzed in this paper, with particular focusing on the asymmetry problem. Furthermore, RBF neural network was applied to obtaining reasonable tuning parameters and a control algorithm of proposed controller was designed. Finally, laboratory experiments were developed to verify the validity and effectiveness of proposed compound control method. The testing results, compared with those for other controllers, proved that the proposed compound control method can acquire high movement precision and respond speed in the system of hydraulically driven shearer drum lifting with different control conditions.

High Bandwidth Motion Control for Multi-Axis Servohydraulic Mechanisms

2007 ◽  
Author(s):  
A. R. Plummer
Keyword(s):  
Motion Control ◽  
Degrees Of Freedom ◽  
Control Method ◽  
Earthquake Simulation ◽  
Control Approach ◽  
Six Degrees Of Freedom ◽  
Modes Of Vibration ◽  
High Bandwidth ◽  
Rigid Mass ◽  
Acceleration Tracking

A practical motion control method is presented for multiaxis parallel servohydraulic mechanisms in which the payload behaves as a rigid mass. The ability of this method to decouple the control axes is demonstrated. A modal control approach is used – i.e. the modes of vibration of the system are controlled individually. These modes are dependent on the inertial properties of the payload and the compliance of the actuators due to oil compressibility. For each mode, a partial non-linear dynamic inversion is performed in the control loop. To avoid the need to differentiate the position feedback signals, accelerometers are also used, and three-element motion state vectors are estimated using composite filtering. Command feedforward is used to increase the tracking bandwidth, and the closed-loop part of the controller can be conceived as a model-based disturbance observer. Simulation results are presented based on a detailed validated model of a large vibration table used for earthquake simulation. Just three of the six degrees-of-freedom of the table are considered, and the results for horizontal acceleration tracking response are presented, along with the ability of the controller to reject the ‘overturning moment’.

scholarly journals A Manipulator Control Method Based on Deep Deterministic Policy Gradient with Parameter Noise

2021 ◽  
Author(s):  
Haifei Zhang ◽  
Xu Jian ◽  
Liting Lei ◽  
Fang Wu ◽  
Lanmei Qian ◽  
...  
Keyword(s):  
Motion Control ◽  
Control Method ◽  
State Variables ◽  
Control Approach ◽  
Environment Model ◽  
Policy Gradient ◽  
The Stability ◽  
Reinforcement Learning Models ◽  
Policy Optimization ◽  
Manipulator Control

Abstract Focusing on the motion control problem of two link manipulator, a manipulator control approach based on deep deterministic policy gradient with parameter noise is proposed. Firstly, the manipulator simulation environment is built. And then the three deep reinforcement learning models named the deep deterministic policy gradient (DDPG), asynchronous advantage actor-critical (A3C) and distributed proximal policy optimization (DPPO) are established for training according to the target setting, state variables and reward & punishment mechanism of the environment model. Finally the motion control of two link manipulator is realized. After comparing and analyzing the three models, the DDPG approach based on parameter noise is proposed for further research to improve its applicability, so as to cut down the debugging time of the manipulator model and reach the goal smoothly. The experimental results indicate that the DDPG approach based on parameter noise can control the motion of two link manipulator effectively. The convergence speed of the control model is significantly promoted and the stability after convergence is improved. In comparison with the traditional control approach, the DDPG control approach based on parameter noise has higher efficiency and stronger applicability.

Study on Simulation System of Incremental Photoelectric Encoder

2013 ◽  
Vol 321-324 ◽  
pp. 582-585
Author(s):  
Hai Hui Yang
Keyword(s):  
Signal Processing ◽  
Virtual Reality ◽  
Motion Control ◽  
Control Method ◽  
Pulse Signal ◽  
Simulation System ◽  
Simulation Software ◽  
Virtual Simulation ◽  
Virtual Reality Technology ◽  
Photoelectric Encoder

To change the phenomenon of“Being an armchair strategist” in the research on the photoelectric encoder,the simulation system of that had been researched using virtual-reality technology. Thebasic principle of the photoelectric encoder was expounded. The developmentstrategy of the simulation software was introduced. Some key problems and theirsolutions, including drawing of grid line and motion control method, voltagesignal and the pulse signal processing and display and parameter adjustmentmethod, were put forward in development. Finally, a virtual simulation examplewas provided.

ICMA: AN EFFICIENT INTEGRATED CONGESTION CONTROL APPROACH

2019 ◽  
Vol 14 ◽  
Author(s):  
Tayyab Khan ◽  
Karan Singh ◽  
Kamlesh C. Purohit
Keyword(s):  
Congestion Control ◽  
Packet Loss ◽  
Control Method ◽  
Multicast Communication ◽  
Bandwidth Utilization ◽  
File Transfer ◽  
Control Approach ◽  
Communication Technique ◽  
Control Scheme ◽  
Multiparty Video Conferencing

Background: With the growing popularity of various group communication applications such as file transfer, multimedia events, distance learning, email distribution, multiparty video conferencing and teleconferencing, multicasting seems to be a useful tool for efficient multipoint data distribution. An efficient communication technique depends on the various parameters like processing speed, buffer storage, and amount of data flow between the nodes. If data exceeds beyond the capacity of a link or node, then it introduces congestion in the network. A series of multicast congestion control algorithms have been developed, but due to the heterogeneous network environment, these approaches do not respond nor reduce congestion quickly whenever network behavior changes. Objective: Multicasting is a robust and efficient one-to-many (1: M) group transmission (communication) technique to reduced communication cost, bandwidth consumption, processing time and delays with similar reliability (dependability) as of regular unicast. This patent presents a novel and comprehensive congestion control method known as integrated multicast congestion control approach (ICMA) to reduce packet loss. Methods: The proposed mechanism is based on leave-join and flow control mechanism along with proportional integrated and derivate (PID) controller to reduce packet loss, depending on the congestion status. In the proposed approach, Proportional integrated and derivate controller computes expected incoming rate at each router and feedback this rate to upstream routers of the multicast network to stabilize their local buffer occupancy. Results: Simulation results on NS-2 exhibit the immense performance of the proposed approach in terms of delay, throughput, bandwidth utilization, and packet loss than other existing methods. Conclusion: The proposed congestion control scheme provides better bandwidth utilization and throughput than other existing approaches. Moreover, we have discussed existing congestion control schemes with their research gaps. In the future, we are planning to explore the fairness and quality of service issue in multicast communication.

scholarly journals A Critical Review of Supersonic Flow Control for High-Speed Applications

2021 ◽  
Vol 11 (15) ◽  
pp. 6899
Author(s):  
Abdul Aabid ◽  
Sher Afghan Khan ◽  
Muneer Baig
Keyword(s):  
Supersonic Flow ◽  
Flow Control ◽  
Active Control ◽  
Critical Review ◽  
High Speed ◽  
Passive Control ◽  
Control Method ◽  
Sudden Expansion ◽  
Control Approach ◽  
Cost Efficient

In high-speed fluid dynamics, base pressure controls find many engineering applications, such as in the automobile and defense industries. Several studies have been reported on flow control with sudden expansion duct. Passive control was found to be more beneficial in the last four decades and is used in devices such as cavities, ribs, aerospikes, etc., but these need additional control mechanics and objects to control the flow. Therefore, in the last two decades, the active control method has been used via a microjet controller at the base region of the suddenly expanded duct of the convergent–divergent (CD) nozzle to control the flow, which was found to be a cost-efficient and energy-saving method. Hence, in this paper, a systemic literature review is conducted to investigate the research gap by reviewing the exhaustive work on the active control of high-speed aerodynamic flows from the nozzle as the major focus. Additionally, a basic idea about the nozzle and its configuration is discussed, and the passive control method for the control of flow, jet and noise are represented in order to investigate the existing contributions in supersonic speed applications. A critical review of the last two decades considering the challenges and limitations in this field is expressed. As a contribution, some major and minor gaps are introduced, and we plot the research trends in this field. As a result, this review can serve as guidance and an opportunity for scholars who want to use an active control approach via microjets for supersonic flow problems.

scholarly journals A Novel Adaptive Control Approach Based on Available Headroom of the VSC-HVDC for Enhancement of the AC Voltage Stability

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3222
Author(s):  
Duc Nguyen Huu
Keyword(s):  
Adaptive Control ◽  
Voltage Stability ◽  
Reactive Power ◽  
Control Method ◽  
Offshore Wind ◽  
Voltage Source ◽  
Long Distance ◽  
Control Approach ◽  
Hvdc System ◽  
Voltage Support

Increasing offshore wind farms are rapidly installed and planned. However, this will pose a bottle neck challenge for long-distance transmission as well as inherent variation of their generating power outputs to the existing AC grid. VSC-HVDC links could be an effective and flexible method for this issue. With the growing use of voltage source converter high-voltage direct current (VSC-HVDC) technology, the hybrid VSC-HVDC and AC system will be a next-generation transmission network. This paper analyzes the contribution of the multi VSC-HVDC system on the AC voltage stability of the hybrid system. A key contribution of this research is proposing a novel adaptive control approach of the VSC-HVDC as a so-called dynamic reactive power booster to enhance the voltage stability of the AC system. The core idea is that the novel control system is automatically providing a reactive current based on dynamic frequency of the AC system to maximal AC voltage support. Based on the analysis, an adaptive control method applied to the multi VSC-HVDC system is proposed to realize maximum capacity of VSC for reactive power according to the change of the system frequency during severe faults of the AC grid. A representative hybrid AC-DC network based on Germany is developed. Detailed modeling of the hybrid AC-DC network and its proposed control is derived in PSCAD software. PSCAD simulation results and analysis verify the effective performance of this novel adaptive control of VSC-HVDC for voltage support. Thanks to this control scheme, the hybrid AC-DC network can avoid circumstances that lead to voltage instability.

Sign in / Sign up

Export Citation Format

Share Document