scholarly journals Reducing the Frame Vibration of Delta Robot in Pick and Place Application: An Acceleration Profile Optimization Approach

2018 ◽  
Vol 2018 ◽  
pp. 1-15 ◽  
Author(s):  
Hongtai Cheng ◽  
Wei Li
Keyword(s):  
Surrogate Model ◽  
High Speed ◽  
Gaussian Process Regression ◽  
Frame Structure ◽  
Manufacturing Cost ◽  
Optimization Approach ◽  
Pick And Place ◽  
Delta Robot ◽  
Profile Optimization ◽  
Acceleration Profile

Delta robot is typically mounted on a frame and performs high speed pick and place tasks from top to bottom. Because of its outstanding accelerating capability and higher center of mass, the Delta robot can generate significant frame vibration. Existing trajectory smoothing methods mainly focus on vibration reduction for the robot instead of the frame, and modifying the frame structure increases the manufacturing cost. In this paper, an acceleration profile optimization approach is proposed to reduce the Delta robot-frame vibration. The profile is determined by the maximum jerk, acceleration, and velocity. The pick and place motion (PPM) and resulting frame vibration are analyzed in frequency domain. Quantitative analysis shows that frame vibration can be reduced by altering those dynamic motion parameters. Because the analytic model is derived based on several simplifications, it cannot be directly applied. A surrogate model-based optimization method is proposed to solve the practical issues. By directly executing the PPM with different parameters and measuring the vibration, a model is derived using Gaussian Process Regression (GPR). In order to reduce the frame vibration without sacrificing robot efficiency, those two goals are fused together according to their priorities. Based on the surrogate model, a single objective optimization problem is formulated and solved by Genetic Algorithm (GA). Experimental results show effectiveness of the proposed method. Behavior of the optimal parameters also verifies the robot-frame vibration mechanism.

Asymmetric Arm Design on Delta Robot System

2014 ◽  
Author(s):  
Tsung-Liang Wu ◽  
Jih-Hsiang Yeh ◽  
Cheng-Chen Yang
Keyword(s):  
Energy Saving ◽  
High Speed ◽  
Kinematic Model ◽  
Industrial Applications ◽  
Critical Parameters ◽  
Robot System ◽  
System Cost ◽  
Excited Vibration ◽  
Pick And Place ◽  
Delta Robot

The Delta robot system is widely used in high speed (4 cycles/s at 25-200-25 mm) pick-and-place process in production line. Some industrial applications include photo-voltaic (PV), food process, and electronic assembly, and so on. The energy saving and system cost are two critical parameters for designing the next generation of pick-and-place system. To achieve these goals, a light-weight moving structure with sufficient strength to overcome the excited vibration will be one of the solutions. In this paper, an asymmetric arm design is proposed and fabricated to gain the benefit of strength-to-weight. The asymmetric arm is designed by reinforcing a specific direction and is validated the vibration suppression capability both by simulation and experiment. A position controller that is derived from the kinematic model of Delta robot is utilized to manipulate the robot under a forward-backward motion with a polynomial trajectory with 200 mm displacement. The residual vibration, then, was measured after the forward-backward motion to compare the settling performance between symmetric- and asymmetric-arms on the Delta robot system, respectively. The results conclude as following: (1) The asymmetric arms perform slightly worse (0.03 sec more in settling time) than symmetric arm but there is 15% weight reducing comparing to symmetric arm. (2) Both energy saving and system cost reducing would be achieved by utilizing actuators with lower power consumption and fabrication on carbon fiber arms with mass customization.

The Influence of Partial Force Balancing on the Shaking Moments, Contact Forces, and Precision of a Delta Robot-Like Manipulator in a Compliant Frame

2018 ◽  
Author(s):  
Jan J. de Jong ◽  
J. P. Meijaard ◽  
Volkert van der Wijk
Keyword(s):  
High Speed ◽  
Contact Forces ◽  
Force Balance ◽  
Dynamic Loads ◽  
Accuracy Improvement ◽  
End Effector ◽  
Pick And Place ◽  
Delta Robot ◽  
Full Force ◽  
Typical Design

For the Delta robot, a high-speed parallel pick-and-place manipulator, base vibrations are a significant problem. Especially since the Delta robot is suspended above its workpiece, it requires a large, stiff, and heavy base frame for fast and accurate motions. Dynamic balancing of the shaking forces and the shaking moments is a known technique to reduce the dynamic loads on the base frame and to the surroundings. In this paper it is investigated how solely with partial force balancing, dynamic loads and pick-and-place accuracy of a Delta robot-like manipulator can be improved, considering also the compliance of the base frame. This is done since partial force balance solutions can be implemented relatively simply in the current Delta robot designs, whereas full force and moment balance solutions are complex to apply in practice. Numerical simulations with a representative planar model of a Delta robot-like manipulator with a compliant base frame show that with an increasing amount of force balance the shaking moments increase up to 16% for full force balance. The floor contact forces first reduce and then increase with increasing force balance. With 43% force balance the floor contact forces are minimal, giving a 63% reduction. The end-effector accuracy slightly improves with increasing force balance until full force balance yields a 31% accuracy improvement. A further increase of the force (over) balance shows a 59% improvement of end-effector accuracy for 350% force balance. These effects are mainly due to the typical design of the Delta robot base frame and the way the robot is mounted to it.

A Comparative Study on the Pick-and-Place Trajectories for a Delta Robot

2016 ◽  
Author(s):  
Zexiao Xie ◽  
Peixin Wu ◽  
Ping Ren
Keyword(s):  
Comparative Study ◽  
High Speed ◽  
Computation Time ◽  
Optimization Methods ◽  
Terminal State ◽  
Industrial Robots ◽  
Piecewise Polynomials ◽  
Pick And Place ◽  
Dynamic Performances ◽  
Delta Robot

A comparative study on the pick-and-place trajectories for high-speed Delta robots is presented in this paper. The Adept Cycle has been widely accepted as a standardized pick-and-place trajectory for industrial robots. The blending curves and optimization methods to smooth this trajectory are briefly surveyed. Three major types of trajectories: Lamé curves, clothoids and piecewise polynomials, are selected as candidates to be compared. The processes to generate these trajectories are briefly reviewed. The trajectories are firstly compared in term of their computation time. Then, based on a dynamic model and an experimental prototype of the Delta robot, different combinations of the geometric paths and motion profiles are compared in terms of power consumption, terminal state accuracy and residual vibration. The effects of trajectory configurations and parameters on the robot’s dynamic performances are investigated. Through a comprehensive analysis on both simulation and experimental results, a near-optimal pick-and-place trajectory for the Delta robot is identified and validated.

Dynamic Conveyor Tracking Control of a Delta Robot

2016 ◽  
Vol 679 ◽  
pp. 43-48 ◽  
Author(s):  
Guo Ying Zhang ◽  
Guan Feng Liu ◽  
Xiao Bin Guo ◽  
Xie Yuan Lin
Keyword(s):  
High Speed ◽  
Vision System ◽  
Conveyor Belt ◽  
Torque Control ◽  
Tracking Problem ◽  
Control Scheme ◽  
Pick And Place ◽  
Time Position ◽  
Delta Robot ◽  
Computed Torque

For general dynamic pick and place tasks that the objects are transferred with high speed by the conveyor belt, the capability of a delta robot to track the traveling objects is very important for the efficiency. To meet the needs of precision and smooth control, a computed-torque control scheme for conveyor tracking is implemented in this paper. For higher efficiency and accuracy, computer vision system, encoder and conveyor belt region are incorporated into the control scheme. Dividing the conveyor belt into three regions, the robot is commanded to track, pick and give up according to the subregions. Conveyor belt is equipped with an encoder that provides the controller with real-time position and speed of the belt. Based upon those informations, the controller automatically compensates the end positions with respect to the belt to adjust for the position of the conveyor. Then, the conveyor tracking problem is converted to a subregional tracking problem.

scholarly journals Design and Development of Multipurpose Delta Robot

2021 ◽  
Vol 9 (8) ◽  
pp. 1471-1475
Author(s):  
Dr. Anil Sahu
Keyword(s):  
High Speed ◽  
Degrees Of Freedom ◽  
Maximum Acceleration ◽  
Work Volume ◽  
Pick And Place ◽  
Fast Motion ◽  
Delta Robot ◽  
Cost Efficient ◽  
Parallel Configuration ◽  
Future Work

Abstract: This report represents an designing and simulating ideal pick and place robot which should carry out the operations in minimum time and should also be cost efficient. It is four degrees of freedom parallel configuration used for very high speed pick and place operations. The objectives of this report are designing a Delta robot capable of carrying 1kg payload, achieving a cycle rate of 120 cycles per minute covering a work volume of 400x300x200 mm3. The project involves Kinematic & Dynamic modeling of the robot for the above specifications. The kinematic parameters, involving the lengths of the bicep and forearm, are calculated based on the work volume requirements and the dynamic parameters, involving the motor torque and speed, are calculated based on the maximum acceleration requirements and the inertia of the system. The project further involves the structural analysis of the robot which deals with the proper sizing of the mechanical structure which should be capable of withstanding the high torque and acceleration required for smooth and fast motion. The future work involves integrating the mechanical system with the control system and programming the system for a particular application

scholarly journals Modeling the Excess Velocity of Low-Viscous Taylor Droplets in Square Microchannels

Fluids ◽  
2019 ◽  
Vol 4 (3) ◽  
pp. 162 ◽  
Author(s):  
Thorben Helmers ◽  
Philip Kemper ◽  
Jorg Thöming ◽  
Ulrich Mießner
Keyword(s):  
High Speed ◽  
Process Intensification ◽  
Continuous Phase ◽  
Channel Cross Section ◽  
Optimization Approach ◽  
Mean Flow ◽  
Bypass Flow ◽  
Wall Film ◽  
Proposed Model ◽  
The Mean

Microscopic multiphase flows have gained broad interest due to their capability to transfer processes into new operational windows and achieving significant process intensification. However, the hydrodynamic behavior of Taylor droplets is not yet entirely understood. In this work, we introduce a model to determine the excess velocity of Taylor droplets in square microchannels. This velocity difference between the droplet and the total superficial velocity of the flow has a direct influence on the droplet residence time and is linked to the pressure drop. Since the droplet does not occupy the entire channel cross-section, it enables the continuous phase to bypass the droplet through the corners. A consideration of the continuity equation generally relates the excess velocity to the mean flow velocity. We base the quantification of the bypass flow on a correlation for the droplet cap deformation from its static shape. The cap deformation reveals the forces of the flowing liquids exerted onto the interface and allows estimating the local driving pressure gradient for the bypass flow. The characterizing parameters are identified as the bypass length, the wall film thickness, the viscosity ratio between both phases and the C a number. The proposed model is adapted with a stochastic, metaheuristic optimization approach based on genetic algorithms. In addition, our model was successfully verified with high-speed camera measurements and published empirical data.

scholarly journals Lightweight and maintainable rotary-wing UAV frame from configurable design to detailed design

2021 ◽  
Vol 13 (7) ◽  
pp. 168781402110349
Author(s):  
Huiqiang Guo ◽  
Mingzhe Li ◽  
Pengfei Sun ◽  
Changfeng Zhao ◽  
Wenjie Zuo ◽  
...  
Keyword(s):  
Design Method ◽  
Geometric Model ◽  
Optimization Method ◽  
Frame Structure ◽  
Manufacturing Cost ◽  
Detailed Design ◽  
High Manufacturing Cost ◽  
The Military ◽  
Rotary Wing ◽  
Novel Design

Rotary-wing unmanned aerial vehicles (UAVs) are widespread in both the military and civilian applications. However, there are still some problems for the UAV design such as the long design period, high manufacturing cost, and difficulty in maintenance. Therefore, this paper proposes a novel design method to obtain a lightweight and maintainable UAV frame from configurable design to detailed design. First, configurable design is implemented to determine the initial design domain of the UAV frame. Second, topology optimization method based on inertia relief theory is used to transform the initial geometric model into the UAV frame structure. Third, process design is considered to improve the manufacturability and maintainability of the UAV frame. Finally, dynamic drop test is used to validate the crashworthiness of the UAV frame. Therefore, a lightweight UAV frame structure composed of thin-walled parts can be obtained and the design period can be greatly reduced via the proposed method.

scholarly journals Towards an Efficient CNN Inference Architecture Enabling In-Sensor Processing

Sensors ◽  
2021 ◽  
Vol 21 (6) ◽  
pp. 1955
Author(s):  
Md Jubaer Hossain Pantho ◽  
Pankaj Bhowmik ◽  
Christophe Bobda
Keyword(s):  
Power Consumption ◽  
High Speed ◽  
Image Sensor ◽  
Machine Learning Algorithms ◽  
Hierarchical Optimization ◽  
Computation Method ◽  
Optimization Approach ◽  
Efficient Computation ◽  
Feature Maps ◽  
Dynamic Power

The astounding development of optical sensing imaging technology, coupled with the impressive improvements in machine learning algorithms, has increased our ability to understand and extract information from scenic events. In most cases, Convolution neural networks (CNNs) are largely adopted to infer knowledge due to their surprising success in automation, surveillance, and many other application domains. However, the convolution operations’ overwhelming computation demand has somewhat limited their use in remote sensing edge devices. In these platforms, real-time processing remains a challenging task due to the tight constraints on resources and power. Here, the transfer and processing of non-relevant image pixels act as a bottleneck on the entire system. It is possible to overcome this bottleneck by exploiting the high bandwidth available at the sensor interface by designing a CNN inference architecture near the sensor. This paper presents an attention-based pixel processing architecture to facilitate the CNN inference near the image sensor. We propose an efficient computation method to reduce the dynamic power by decreasing the overall computation of the convolution operations. The proposed method reduces redundancies by using a hierarchical optimization approach. The approach minimizes power consumption for convolution operations by exploiting the Spatio-temporal redundancies found in the incoming feature maps and performs computations only on selected regions based on their relevance score. The proposed design addresses problems related to the mapping of computations onto an array of processing elements (PEs) and introduces a suitable network structure for communication. The PEs are highly optimized to provide low latency and power for CNN applications. While designing the model, we exploit the concepts of biological vision systems to reduce computation and energy. We prototype the model in a Virtex UltraScale+ FPGA and implement it in Application Specific Integrated Circuit (ASIC) using the TSMC 90nm technology library. The results suggest that the proposed architecture significantly reduces dynamic power consumption and achieves high-speed up surpassing existing embedded processors’ computational capabilities.

scholarly journals Catalytic production of impurity-free V3.5+ electrolyte for vanadium redox flow batteries

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Jiyun Heo ◽  
Jae-Yun Han ◽  
Soohyun Kim ◽  
Seongmin Yuk ◽  
Chanyong Choi ◽  
...  
Keyword(s):  
High Speed ◽  
High Performance ◽  
Large Scale ◽  
Catalytic Reduction ◽  
Continuous Production ◽  
Vanadium Redox Flow Battery ◽  
Manufacturing Cost ◽  
Chemical Production ◽  
High Manufacturing Cost ◽  
Vanadium Redox

Abstract The vanadium redox flow battery is considered one of the most promising candidates for use in large-scale energy storage systems. However, its commercialization has been hindered due to the high manufacturing cost of the vanadium electrolyte, which is currently prepared using a costly electrolysis method with limited productivity. In this work, we present a simpler method for chemical production of impurity-free V3.5+ electrolyte by utilizing formic acid as a reducing agent and Pt/C as a catalyst. With the catalytic reduction of V4+ electrolyte, a high quality V3.5+ electrolyte was successfully produced and excellent cell performance was achieved. Based on the result, a prototype catalytic reactor employing Pt/C-decorated carbon felt was designed, and high-speed, continuous production of V3.5+ electrolyte in this manner was demonstrated with the reactor. This invention offers a simple but practical strategy to reduce the production cost of V3.5+ electrolyte while retaining quality that is adequate for high-performance operations.

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