Real-Time Flow Optimization of Hydraulic Manipulator with One Degree of Redundancy Considering Joint Limit Constraint

2021 ◽  
Author(s):  
Linan Li ◽  
Min Cheng ◽  
Ruqi Ding ◽  
Junhui Zhang ◽  
Bing Xu
Keyword(s):  
Real Time ◽  
Projection Method ◽  
Jacobian Matrix ◽  
Gradient Projection ◽  
Redundancy Resolution ◽  
Flow Optimization ◽  
Hydraulic Manipulators ◽  
Time Flow ◽  
Hydraulic Manipulator ◽  
Joint Limit

Abstract Due to the complexity in unstructured environments (e.g., rescue response and forestry logging), more hydraulic manipulators are equipped with one redundant joint to improve their motion flexibility. In addition to considering joint limit constraint and maneuverability optimization like electrically driven manipulators, hydraulic manipulators can optimize flow consumption consider flow optimization aiming at energy saving and flow anti-saturation for redundancy resolution, since multiple joints are supplied by one pump. Therefore, this paper proposes a redundancy resolution method combining the gradient projection method with a weighted Jacobian matrix (GPM-WJM) for real-time flow optimization of the hydraulic manipulator with one degree of redundancy considering joint limit constraint. Its solution consists of two parts: a special solution (the weighted least-norm solution) and a general solution (the projection of the optimization index in the null space of the weighted task Jacobian matrix). Simulations are carried out to verify its effectiveness. The simulation result shows that GPM-WJM can meet the constraints of joint limit without affecting the tool center point (TCP) trajectory and utilize the remaining redundancy to optimize the flow consumption and manipulability in real-time, which can reduce average system flow by 10.45%. Compared with the gradient projection method (GPM) for flow optimization, GPM-WJM can reduce the maximum acceleration when avoiding the joint limits by 80% at the cost of slightly weakening the flow optimization effect, which is beneficial to improve the accuracy of the manipulator in practice.

scholarly journals A new redundancy resolution for underwater vehicle–manipulator system considering payload

2017 ◽  
Vol 14 (5) ◽  
pp. 172988141773393 ◽  
Author(s):  
Yaoyao Wang ◽  
Surong Jiang ◽  
Fei Yan ◽  
Linyi Gu ◽  
Bai Chen
Keyword(s):  
Fuzzy Logic ◽  
Projection Method ◽  
Underwater Vehicle ◽  
Gradient Projection ◽  
Gradient Projection Method ◽  
Redundancy Resolution ◽  
Coordination Problem ◽  
System A ◽  
Weight Factors ◽  
Secondary Objective

For the motion coordination problem between the underwater vehicle and manipulator of the underwater vehicle–manipulator system, a new redundancy resolution method is proposed and investigated. The proposed method mainly has two parts: a fuzzy logic part and a multitasks weighted gradient projection method part. The fuzzy logic part is used to decide the weight factors of the motion distribute matrix and the priorities of all the secondary objectives, while the multitasks weighted gradient projection method part is used to handle the secondary objectives with the weight factors and priorities decided by the fuzzy logic part. Moreover, a new secondary objective is proposed to optimize underwater vehicle–manipulator system’s attitude, which takes the payload into consideration. Finally, the effectiveness of the proposed redundancy resolution is verified through some comparative simulations.

scholarly journals Real-Time Anti-Saturation Flow Optimization Algorithm of the Redundant Hydraulic Manipulator

Actuators ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 11
Author(s):  
Min Cheng ◽  
Linan Li ◽  
Ruqi Ding ◽  
Bing Xu
Keyword(s):  
Real Time ◽  
Optimization Algorithm ◽  
High Speed ◽  
Null Space ◽  
Average Power ◽  
Time Step ◽  
Flow Optimization ◽  
Average Power Consumption ◽  
Hydraulic Manipulator ◽  
Saturation Flow

As a typical single-pump multi-actuator system, the hydraulic manipulator faces the flow saturation problem when moving at a high speed to track a desired trajectory. To overcome this problem, this paper proposes a real-time anti-saturation flow optimization algorithm based on the gradient projection method. By projecting the gradient of the demand flow in the null space of the task Jacobians, this algorithm can reduce the flow demand while enforcing a global volumetric flow limit in real time. The model of a 7-degree-of-freedom (DOF) hydraulic redundant manipulator was established to carry out theoretical derivation and algorithm design. Then, the experimental verification was completed on the real manipulator platform. Experimental results show that this algorithm reduces average demand flow by 9.85% and average power consumption by 310.3 W under no saturation condition. When flow saturation occurs, the algorithm can increase the average endpoint velocity by 7.52% and reduce the maximum directional error by 71.73% with an average calculation time step of 3 ms. The average trajectory position error can also be reduced by 42.59% compared with the anti-saturation algorithm. Therefore, the proposed algorithm can achieve real-time optimization to reduce flow consumption and achieve anti-saturation in practical applications of redundant hydraulic manipulator.

Real-Time Flow Stability Advisor

2020 ◽  
Author(s):  
R. Andreas Burgos S. ◽  
Lars Wollebaek ◽  
Vegard Elverhaug ◽  
Zongchang Yang ◽  
Hatef Khaledi
Keyword(s):  
Real Time ◽  
Flow Stability ◽  
Time Flow

scholarly journals Experimental Verification of Real-Time Flow-Rate Estimations in a Tilting-Ladle-Type Automatic Pouring Machine

2021 ◽  
Vol 11 (15) ◽  
pp. 6701
Author(s):  
Yuta Sueki ◽  
Yoshiyuki Noda
Keyword(s):  
Real Time ◽  
Molten Metal ◽  
Flow Rate ◽  
Kalman Filters ◽  
Estimation Method ◽  
Estimation Methods ◽  
Liquid Volume ◽  
Model Parameters ◽  
Rate Estimation ◽  
Time Flow

This paper discusses a real-time flow-rate estimation method for a tilting-ladle-type automatic pouring machine used in the casting industry. In most pouring machines, molten metal is poured into a mold by tilting the ladle. Precise pouring is required to improve productivity and ensure a safe pouring process. To achieve precise pouring, it is important to control the flow rate of the liquid outflow from the ladle. However, due to the high temperature of molten metal, directly measuring the flow rate to devise flow-rate feedback control is difficult. To solve this problem, specific flow-rate estimation methods have been developed. In the previous study by present authors, a simplified flow-rate estimation method was proposed, in which Kalman filters were decentralized to motor systems and the pouring process for implementing into the industrial controller of an automatic pouring machine used a complicatedly shaped ladle. The effectiveness of this flow rate estimation was verified in the experiment with the ideal condition. In the present study, the appropriateness of the real-time flow-rate estimation by decentralization of Kalman filters is verified by comparing it with two other types of existing real-time flow-rate estimations, i.e., time derivatives of the weight of the outflow liquid measured by the load cell and the liquid volume in the ladle measured by a visible camera. We especially confirmed the estimation errors of the candidate real-time flow-rate estimations in the experiments with the uncertainty of the model parameters. These flow-rate estimation methods were applied to a laboratory-type automatic pouring machine to verify their performance.

A Back Allocation Methodology to Estimate the Real-Time Flow and Assist Production Monitoring

2021 ◽  
Author(s):  
Gabriela Chaves ◽  
Danielle Monteiro ◽  
Virgilio José Martins Ferreira
Keyword(s):  
Real Time ◽  
Input Data ◽  
Oil Field ◽  
Well Testing ◽  
Well Test ◽  
Time Data ◽  
Time Flow ◽  
Well Model ◽  
Operational Information ◽  
The Individual

Abstract Commingle production nodes are standard practice in the industry to combine multiple segments into one. This practice is adopted at the subsurface or surface to reduce costs, elements (e.g. pipes), and space. However, it leads to one problem: determine the rates of the single elements. This problem is recurrently solved in the platform scenario using the back allocation approach, where the total platform flowrate is used to obtain the individual wells’ flowrates. The wells’ flowrates are crucial to monitor, manage and make operational decisions in order to optimize field production. This work combined outflow (well and flowline) simulation, reservoir inflow, algorithms, and an optimization problem to calculate the wells’ flowrates and give a status about the current well state. Wells stated as unsuited indicates either the input data, the well model, or the well is behaving not as expected. The well status is valuable operational information that can be interpreted, for instance, to indicate the need for a new well testing, or as reliability rate for simulations run. The well flowrates are calculated considering three scenarios the probable, minimum and maximum. Real-time data is used as input data and production well test is used to tune and update well model and parameters routinely. The methodology was applied using a representative offshore oil field with 14 producing wells for two-years production time. The back allocation methodology showed robustness in all cases, labeling the wells properly, calculating the flowrates, and honoring the platform flowrate.

Sign in / Sign up

Export Citation Format

Share Document