Adaptive Output Force Tracking Control of Hydraulic Cylinders With Applications to Robot Manipulators

2004 ◽  
Vol 127 (2) ◽  
pp. 206-217 ◽  
Author(s):  
Wen-Hong Zhu ◽  
Jean-Claude Piedboeuf
Keyword(s):  
Friction Force ◽  
Force Control ◽  
Viscous Friction ◽  
Joint Torque ◽  
Chamber Pressure ◽  
Friction Compensation ◽  
Pressure Force ◽  
Viscous Friction Force ◽  
Output Force ◽  
Hydraulic Cylinders

An adaptive output force control scheme for hydraulic cylinders is proposed by using direct output force measurement through loadcells. Due to the large and somewhat uncertain piston friction force, cylinder chamber pressure control with Coulomb-viscous friction prediction may not be sufficient enough to achieve a precise output force control. In the proposed approach, the output force error resulting from direct measurement is used not only for feedback control, but also to update the parameters of an appropriate friction model which includes the Coulomb-viscous friction force in sliding motion and the output force dependent friction force in presliding motion. The L2 and L∞ stability is guaranteed for both the pressure force error and the output force error. Under bounded desired output force and its derivative, asymptotic stability of both the pressure force error and the output force error is also guaranteed. The experimental results demonstrate that a good pressure force control system does not necessarily guarantee a good output force control, and that adaptive friction compensation is superior to fixed-parameter friction compensation. The output force control transfer functions of a robot joint driven by two hydraulic cylinders in pull–pull configuration are limited by ±1.5dB up to 20Hz, tested in free motion and in rigid constraint. The excellent output force (joint torque) control performance implies the dynamic equivalency between a hydraulic cylinder and an electrically-driven motor within the prespecified bandwidth. This allows to emulate an electrically-driven robot by a hydraulic robot.

Dynamics of a Moving Body With the Hole in Its Center and Characteristics of Fluid Flow in a Small Diameter Tube

2009 ◽  
Author(s):  
Toru Maeda ◽  
Akihiro Sato ◽  
Tatsuya Otsuka ◽  
Masatsugu Yoshizawa
Keyword(s):  
Rigid Body ◽  
Average Velocity ◽  
Small Diameter ◽  
Flow Characteristics ◽  
Viscous Friction ◽  
Terminal Velocity ◽  
The Body ◽  
Pressure Force ◽  
Viscous Friction Force ◽  
Moving Body

A rigid body moving with fluid in a narrow tube is expected to be developed for future engineering applications such as a capsule endoscopy, and it is also applied to some parts of industry. This paper deals with the flow characteristics around a single rigid body with a hole in its center and transient motion of the body when the body is influenced by pressure force from upstream. The model considered the width of the gap between the body and the wall is smaller than a diameter of a tube so that the force on the body can be numerically and analytically estimated as a viscous friction force. It was assumed that the flow is axisymmetric, laminar and taken to be Newtonian and incompressible. It was obtained that, with the hole in its center, the terminal velocity of the body becomes smaller than the average velocity at the inlet. Moreover, because there is a stagnation on the body, the pressure increases behind the body.

Dynamic Behavior Analysis of the Slider Crank Linkage using ANSYS Workbench and MATLAB Program

2013 ◽  
Vol 1 (1) ◽  
pp. 42-25
Author(s):  
Nabil N. Swadi
Keyword(s):  
Graphical Method ◽  
Joint Torque ◽  
Pressure Force ◽  
Matlab Program ◽  
Element Simulation ◽  
Acceleration Method ◽  
Complete Revolution ◽  
Two Phases ◽  
Good Agreement ◽  
Ansys Workbench

This paper is concerned with the study of the kinematic and kinetic analysis of a slider crank linkage using D'Alembert's principle. The links of the considered mechanism are assumed to be rigid. The analytical solution to observe the motion (displacement, velocity, and acceleration), reactions at each joint, torque required to drive the mechanism and the shaking force have been computed by a computer program written in MATLAB language over one complete revolution of the crank shaft. The results are compared with a finite element simulation carried out by using ANSYS Workbench software and are found to be in good agreement. A graphical method (relative velocity and acceleration method) has been also applied for two phases of the crank shaft (q2 = 10° and 130°). The results obtained from this method (graphical) are compared with those obtained from analytical and numerical method and are found very acceptable. To make the analysis linear the friction force on the joints and sliding interface are neglected. All results, in this work, are obtained when the crank shaft turns at a uniform angular velocity (w2 = 188.5 rad/s) and time dependent gas pressure force on the slider crown.

Modelling and Analysis of a Grout Delivery Mechanism in the Remote Spray Lining of Shafts

1996 ◽  
Author(s):  
Liu Hongzhao ◽  
E. Appleton
Keyword(s):  
Relative Velocity ◽  
Viscous Friction ◽  
Emission Angle ◽  
Inertia Force ◽  
Viscous Damping ◽  
Friction Forces ◽  
Viscous Friction Force ◽  
Full Discussion ◽  
Delivery Mechanism ◽  
Driving Torque

Abstract A thorough analysis on the characteristics of a grout delivery mechanism in the lining of shafts has been accomplished. The dynamic equation of this spraying mechanism has been established and can describe the system’s performance properties under different conditions of viscous friction forces. The analysis introduces a combined viscous damping coefficient c* and a ratio λ between viscous friction force and inertia force. It is proved theoretically that the relative velocity of the grout is less than the implicate velocity and the emission angle α described in the paper is always larger than 45 °. Numerical simulations are performed by feeding various different parameters into the model. A full discussion of the effects of different variables is presented. Additionally, a formula for calculating the driving torque and power is developed. These studies provide an understanding of the properties of this mechanism and should prove useful in guiding its design and operation.

Study of Dominant Performance Characteristics in Robot Transmissions

1993 ◽  
Vol 115 (3) ◽  
pp. 472-482 ◽  
Author(s):  
H. Schempf ◽  
D. R. Yoerger
Keyword(s):  
Force Control ◽  
Closed Loop ◽  
Stability Margin ◽  
Viscous Friction ◽  
Open Loop ◽  
Phase Lag ◽  
Stability Margins ◽  
Loop Bandwidth ◽  
Hard Contact ◽  
Following Error

Six different transmission types suitable for robotic manipulators were compared in an experimental and theoretical study. Single-degree-of-freedom mechanisms based on the different transmissions were evaluated in terms of force control performance, achievable bandwidth, and stability properties in hard contact tasks. Transmission types considered were (1) cable reducer, (2) harmonic drive, (3) cycloidal disk reducer, (4) cycloidal cam reducer, (5) ball reducer, and (6) planetary/cycloidal gear head. Open loop torque following error, attenuation and phase lag, and closed loop bandwidth and stability margin were found to be severely dominated by levels of inertia, stiffness distribution and variability, stiction, coulomb and viscous friction, and ripple torque. These aspects were quantified and shown to vary widely among all transmissions tested. The degree of nonlinearity inherent in each transmission affected its open and closed loop behavior directly, and limited the effectiveness of controller compensation schemes. Simple transmission models based on carefully measured transmission characteristics are shown to predict stability margins and achievable force-control bandwidths in hard contact to within a 5 to 15 percent error margin.

Coordination Control of Arm Using Antagonistic Actuators

2002 ◽  
Vol 14 (3) ◽  
pp. 270-277 ◽  
Author(s):  
Toru Oshima ◽  
◽  
Tomohiko Fujikawa ◽  
Minayori Kumamoto ◽  
◽  
...  
Keyword(s):  
Force Control ◽  
Skeletal Muscles ◽  
Control Mode ◽  
Coordination Control ◽  
Mechanical Joint ◽  
Output Force ◽  
Link Model ◽  
The Difference ◽  
The Relationship ◽  
Antagonistic Muscles

In a mechanical joint drive used in robot arms, 1 actuator drives each joint. To drive joints in musculoskeletal animal limbs, in which skeletal muscles are used as actuators, a pair of bi-articular muscles drives 2 joints simultaneously in addition to a pair of monoarticular muscles for driving 1 joint. In our study, the mutual coordination of antagonistic mono-articular and antagonistic bi-articular muscles in in the horizontal arm plane were examined using electromyogram, results were analyzed by a mechanical 2-joint link model, and the relationship between the pattern of coordination of antagonistic muscles and output force generated by the arm clarified. A neural network model that generates the pattern of coordination was proposed to clarify the difference between conventional robots and animals in the force control mode for limbs.

Statistically optimized FOPID for output force control of SEAs

2018 ◽  
Vol 32 (5) ◽  
pp. 231-241
Author(s):  
Somayeh Norouzi Ghazbi ◽  
Alireza Akbarzadeh ◽  
Iman Kardan
Keyword(s):  
Force Control ◽  
Output Force

Dynamic Modeling and Model-Based Force Control of a 3-DOF Translational Parallel Robot

2014 ◽  
Vol 1006-1007 ◽  
pp. 609-617 ◽  
Author(s):  
Shu Hua Gao ◽  
Rui Fan ◽  
Dan Wang
Keyword(s):  
Dynamic Model ◽  
Control Strategy ◽  
Force Control ◽  
Virtual Work ◽  
Parallel Robot ◽  
Cnc Machine Tools ◽  
Distribution Factor ◽  
Cnc Machine ◽  
Model Based ◽  
Output Force

A 3-axis parallel loading mechanism, which works as a multi-axis load simulator, is proposed for reliability test of multi-axis CNC machine tools by exerting specific load spectrums on the spindle. To achieve efficient loading force control, dynamic model of the 3-DOF translational parallel robot is derived via the virtual work principle and is embedded into the control strategy to build a model-based control scheme. A mass distribution factor is introduced and the rotating inertia of the limbs is neglected to simplify the dynamics equations for better real-time control performance. This simplification method is verified by comparison with the complete dynamics model. Then the simplified dynamic model is integrated with a PI (proportional–integral) controller with feedforward to control the moving platform’s output force in the task space and this control strategy is verified through co-simulations with MATLAB/Simulink and ADAMS. Simulation results show that the proposed model-based PI controller is effective to control the three-dimensional output force of the 3-DOF translational parallel robot.

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