Collision response and obstacle avoidance of the tethered-space net robot system with non-target objects

2022 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Weiliang Zhu ◽  
Zhaojun Pang ◽  
Jiyue Si ◽  
Zhonghua Du
Keyword(s):  
Obstacle Avoidance ◽  
Collision Detection ◽  
Space Debris ◽  
Detection Method ◽  
Correction Method ◽  
Robot System ◽  
Content Type ◽  
Collision Model ◽  
Collision Response ◽  
Detection Failure

Purpose This paper aims to study the encounter issues of the Tethered-Space Net Robot System (TSNRS) with non-target objects on orbit during the maneuver, including the collision issues with small space debris and the obstacle avoidance from large obstacles. Design/methodology/approach For the collision of TSNRS with small debris, the available collision model of the tethered net and its limitation is discussed, and the collision detection method is improved. Then the dynamic response of TSNRS is studied and a closed-loop controller is designed. For the obstacle avoidance, the variable enveloping circle of the TSNRS has coupled with the artificial potential field (APF) method. In addition, the APF is improved with a local trajectory correction method to avoid the overbending segment of the trajectory. Findings The collision model coupled with the improved collision detection method solves the detection failure and speeds up calculation efficiency by 12 times. Collisions of TSNRS with small debris make the local thread stretch and deforms finally making the net a mess. The boundary of the disturbance is obtained by a series of collision tests, and the designed controller not only achieved the tracking control of the TSNRS but also suppressed the disturbance of the net. Practical implications This paper fills the gap in the research on the collision of the tethered net with small debris and makes the collision model more general and efficient by improving the collision detection method. And the coupled obstacle avoidance method makes the process of obstacle avoidance safer and smoother. Originality/value The work in this paper provides a reference for the on-orbit application of TSNRS in the active space debris removal mission.

Collision detection method for industrial robot based on envelope-like lines

2019 ◽  
Vol 46 (4) ◽  
pp. 510-517 ◽  
Author(s):  
Tie Zhang ◽  
JingDong Hong
Keyword(s):  
False Alarm ◽  
False Alarm Rate ◽  
External Force ◽  
Collision Detection ◽  
Detection Method ◽  
Industrial Robots ◽  
Detection Sensitivity ◽  
Content Type ◽  
Additional Equipment ◽  
Highly Sensitive

Purpose Successful sensorless collision detection by a robot depends on the accuracy with which the external force/torque can be estimated. Compared with collaborative robots, industrial robots often have larger parameter values of their dynamic models and larger errors in parameter identification. In addition, the friction inside a reducer affects the accuracy of external force estimation. The purpose of this paper is to propose a collision detection method for industrial robots. The proposed method does not require additional equipment, such as sensors, and enables highly sensitive collision detection while guaranteeing a zero false alarm rate. Design/methodology/approach The error on the calculated torque for a robot in stable motion is analyzed, and a typical torque error curve is presented. The variational characteristics of the joint torque error during a collision are analyzed, and collisions are classified into two types: hard and soft. A pair of envelope-like lines with an effect similar to that of the true envelope lines is designed. By using these envelope-like lines, some components of the torque calculation error can be eliminated, and the sensitivity of collision detection can be improved. Findings The proposed collision detection method based on envelope-like lines can detect hard and soft collisions during the motion of industrial robots. In repeated experiments without collisions, the false alarm rate was 0 per cent, and in repeated experiments with collisions, the rate of successful detection was 100 per cent. Compared with collision detection method based on symmetric thresholds, the proposed method has a smaller detection delay and the same detection sensitivity for different joint rotation directions. Originality/value A collision detection method for industrial robots based on envelope-like lines is proposed in this paper. The proposed method does not require additional equipment or complex algorithms, and highly sensitive collision detection can be achieved with zero false alarms. The proposed method is low in cost and highly practical and can be widely used in applications involving industrial robots.

3D fabric dynamic simulation based on Mapreduce

2015 ◽  
Vol 27 (6) ◽  
pp. 793-802 ◽  
Author(s):  
Hengliang Shi ◽  
Xiaolei Bai ◽  
Jianhui Duan
Keyword(s):  
Real Time ◽  
Collision Detection ◽  
Detection Algorithm ◽  
Calculation Model ◽  
3D Animation ◽  
Content Type ◽  
Collision Response ◽  
Simulation Based ◽  
Mass Spring Model ◽  
Mass Spring

Purpose – In cloth animation field, the collision detection of fabric under external force is very complex, and difficult to satisfy the needs of reality feeling and real time. The purpose of this paper is to improve reality feeling and real-time requirement. Design/methodology/approach – This paper puts forward a mass-spring model with building bounding-box in the center of particle, and designs the collision detection algorithm based on Mapreduce. At the same time, a method is proposed to detect collision based on geometric unit. Findings – The method can quickly detect the intersection of particle and triangle, and then deal with collision response according to the physical characteristics of fabric. Experiment shows that the algorithm improves real-time and authenticity. Research limitations/implications – Experiments show that 3D fabric simulation can be more efficiency through parallel calculation model − Mapreduce. Practical implications – This method can improve the reality feeling, and reduce calculation quantity. Social implications – This collision-detection can be used into more fields such as 3D games, aero simulation training and garments automation. Originality/value – This model and method have originality, and can be used to 3D animation, digital entertainment, and garment industry.

Manipulator residual estimation and its application in collision detection

2018 ◽  
Vol 45 (3) ◽  
pp. 354-362 ◽  
Author(s):  
Mingming Guo ◽  
Hua Zhang ◽  
Chuncheng Feng ◽  
Manlu Liu ◽  
Jianwen Huo
Keyword(s):  
False Alarm ◽  
Collision Detection ◽  
Detection Method ◽  
Human Robot Interaction ◽  
Dynamic Threshold ◽  
Model Parameters ◽  
Detection Accuracy ◽  
Robot Interaction ◽  
Content Type ◽  
Non Linear

Purpose This paper aims to present a method to improve the sensitive and low probabilities of false alarm of a manipulator in a human–robot interaction environment, which can improve the performance of the system owing to non-linear uncertainty in the model of the robot controller. Design/methodology/approach A novel collision detection method based on adaptive residual estimation is proposed, promoting the detection accuracy of the collision of the manipulator during operation. First, a general momentum residual estimator is designed to incorporate the non-linear factors of the manipulator (e.g. joint friction, speed and acceleration) into the residual-related uncertainty of the model. Second, model parameters are estimated through gradient correction. The residual filter is used to determine the dynamic threshold, resulting in higher detection accuracy. Finally, the performance of the residual estimation scheme is evaluated by comparing the dynamic threshold with residual in real-time experiments where a single Universal Robot 5 robot end–effector collides with the obstacle. Findings Experimental results demonstrate that the collision detection system can improve sensitivity and lead to low probabilities of false alarm of non-linear uncertainty in the model. Practical implications The method proposed in this article can be applied to industry and human–robot interaction area. Originality/value An adaptive collision detection method is proposed in this paper to address non-linear uncertainties of the model in industrial application.

scholarly journals A New Bacterial Disease on Mandevilla sanderi, Caused by Pseudomonas savastanoi: Lessons Learned for Bacterial Diversity Studies

2012 ◽  
Vol 78 (23) ◽  
pp. 8492-8497 ◽  
Author(s):  
Namis Eltlbany ◽  
Zsa-Zsa Prokscha ◽  
M. Pilar Castañeda-Ojeda ◽  
Ellen Krögerrecklenfort ◽  
Holger Heuer ◽  
...  
Keyword(s):  
Bacterial Diversity ◽  
Host Plants ◽  
Detection Method ◽  
Lessons Learned ◽  
Bacterial Disease ◽  
Content Type ◽  
Restriction Patterns ◽  
Diversity Studies

ABSTRACTLeaf lesions ofMandevilla sanderiwere shown to be caused byPseudomonas savastanoi. While BOX fingerprints were similar forP. savastanoiisolates from different host plants, plasmid restriction patterns and sequencing of plasmid-located pathogenicity determinants revealed thatMandevillaisolates contained similar plasmids distinct from those of other isolates. ArepA-based detection method was established.

Tool workspace consideration for assembly plan generation

2021 ◽  
Vol 41 (5) ◽  
pp. 612-625
Author(s):  
Akram Bedeoui ◽  
Riadh Ben Hadj ◽  
Moncef Hammadi ◽  
Nizar Aifaoui
Keyword(s):  
Collision Detection ◽  
New Product ◽  
Production Costs ◽  
Assembly Sequence ◽  
Content Type ◽  
Plan Generation ◽  
Assembly Sequences ◽  
Dynamic Interference ◽  
Time Decrease

Purpose During the design of a new product, the generation of assembly sequences plans (ASPs) has become one of the most important problems taken into account by researchers. In fact, a good mounting order allows the time decrease of the assembly process which leads to the reduction of production costs. In this context, researchers developed several methods to generate and optimize ASP based on various criteria. Although this paper aims to improve the quality of ASP it is necessary to increase the number of criteria which must be taken into account when generating ASPs. Design/methodology/approach In this paper, an ASP generation approach, which is based on three main algorithms, is proposed. The first one generates a set of assembly sequences based on stability criteria. The obtained results are treated by the second algorithm which is based on assembly tools (ATs) workspace criterion. An illustrative example is used to explain the different steps of this proposed approach. Moreover, a comparative study is done to highlight its advantages. Findings The proposed algorithm verifies, for each assembly sequence, the minimal required workspace of used AT and eliminates the ASPs non-respecting this criterion. Finally, the remaining assembly sequences are treated by the third algorithm to reduce the AT change during the mounting operation. Originality/value The proposed approach introduces the concept of AT workspace to simulate and select ASPs that respect this criterion. The dynamic interference process allows the eventual collision detection between tool and component and avoids it. The proposed approach reduces the AT change during the mounting operations.

Robot obstacle avoidance system using deep reinforcement learning

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Xiaojun Zhu ◽  
Yinghao Liang ◽  
Hanxu Sun ◽  
Xueqian Wang ◽  
Bin Ren
Keyword(s):  
Reinforcement Learning ◽  
Collision Avoidance ◽  
Obstacle Avoidance ◽  
Learning Algorithm ◽  
Optimal Path ◽  
Environmental Parameters ◽  
Working Environment ◽  
Content Type ◽  
Practical Applications ◽  
Human Operators

Purpose Most manufacturing plants choose the easy way of completely separating human operators from robots to prevent accidents, but as a result, it dramatically affects the overall quality and speed that is expected from human–robot collaboration. It is not an easy task to ensure human safety when he/she has entered a robot’s workspace, and the unstructured nature of those working environments makes it even harder. The purpose of this paper is to propose a real-time robot collision avoidance method to alleviate this problem. Design/methodology/approach In this paper, a model is trained to learn the direct control commands from the raw depth images through self-supervised reinforcement learning algorithm. To reduce the effect of sample inefficiency and safety during initial training, a virtual reality platform is used to simulate a natural working environment and generate obstacle avoidance data for training. To ensure a smooth transfer to a real robot, the automatic domain randomization technique is used to generate randomly distributed environmental parameters through the obstacle avoidance simulation of virtual robots in the virtual environment, contributing to better performance in the natural environment. Findings The method has been tested in both simulations with a real UR3 robot for several practical applications. The results of this paper indicate that the proposed approach can effectively make the robot safety-aware and learn how to divert its trajectory to avoid accidents with humans within the workspace. Research limitations/implications The method has been tested in both simulations with a real UR3 robot in several practical applications. The results indicate that the proposed approach can effectively make the robot be aware of safety and learn how to change its trajectory to avoid accidents with persons within the workspace. Originality/value This paper provides a novel collision avoidance framework that allows robots to work alongside human operators in unstructured and complex environments. The method uses end-to-end policy training to directly extract the optimal path from the visual inputs for the scene.

Development of master-slave magnetic anchoring vision robotic system for single-port laparoscopy (SPL) surgery

2018 ◽  
Vol 45 (4) ◽  
pp. 458-468
Author(s):  
Haibo Feng ◽  
Yanwu Zhai ◽  
Yili Fu
Keyword(s):  
Single Port ◽  
Robotic System ◽  
Surgical Robot ◽  
Distribution Analysis ◽  
Robot System ◽  
Content Type ◽  
Blind Area ◽  
Robot Systems ◽  
Single Port Laparoscopy ◽  
And Performance

Purpose Surgical robot systems have been used in single-port laparoscopy (SPL) surgery to improve patient outcomes. This study aims to develop a vision robot system for SPL surgery to effectively improve the visualization of surgical robot systems for relatively complex surgical procedures. Design/methodology/approach In this paper, a new master-slave magnetic anchoring vision robotic system for SPL surgery was proposed. A lighting distribution analysis for the imaging unit of the vision robot was carried out to guarantee illumination uniformity in the workspace during SPL surgery. Moreover, cleaning force for the lens of the camera was measured to assess safety for an abdominal wall, and performance assessment of the system was performed. Findings Extensive experimental results for illumination, control, cleaning force and functionality test have indicated that the proposed system has an excellent performance in providing the visual feedback. Originality/value The main contribution of this paper lies in the development of a magnetic anchoring vision robot system that successfully improves the ability of cleaning the lens and avoiding the blind area in a field of view.

Sign in / Sign up

Export Citation Format

Share Document