Strategy investigation of precise robotic assembly operations with symmetric regular polyhedral objects

1998 ◽  
Vol 212 (7) ◽  
pp. 571-589 ◽  
Author(s):  
H Qiao ◽  
S K Tso
Keyword(s):  
Contact Forces ◽  
Robotic Assembly ◽  
Coordinate Frame ◽  
Force Sensors ◽  
General Strategy ◽  
Actual Movement ◽  
Polyhedral Objects ◽  
Assembly Operations

In this paper, a general strategy for the precise robotic assembly of symmetrical regular polyhedral objects is presented, according to the character of the objects being assembled. The assembly operations with force sensors included are discussed. The general strategy of the operations with force sensors included is first developed. The assembly operations without relying on force sensors are next analysed. This method can be generally used in industry for the precise assembly operations for symmetric regular polyhedral objects. This paper covers the following items: An important problem demanding solution in the general robotic assembly operations with force sensors is presented. The general strategy investigation for the assembly operations with force sensors included is analysed. The mappings, firstly, between the directions of the contact forces and the location of the peg in the hole coordinate frame and, secondly, between the input forces and the actual movement of the peg in the hole coordinate frame are obtained. The general strategy investigation for the robotic assembly operations for symmetric regular polyhedral objects without using force sensors is designed on the basis of the mappings and the general principles in the strategy investigation. The experiments on the precise round and triangular peg—hole systems are presented to prove the validity of the general strategies designed. The strategy of assembly operations for other symmetric regular polyhedral objects without using force sensors is presented.

Robotic Assembly Operation Strategy Investigation Without Force Sensors Through the Research on Contact Point Location and Range of Peg Movement

1996 ◽  
Vol 210 (5) ◽  
pp. 471-485 ◽  
Author(s):  
H Qiao ◽  
B S Dalay ◽  
J A G Knight
Keyword(s):  
High Speed ◽  
Manufacturing Industry ◽  
Contact Point ◽  
Robotic Assembly ◽  
Coordinate Frame ◽  
Force Sensors ◽  
Control Input ◽  
Widespread Application ◽  
Assembly Operation ◽  
Initial Area

The assembly operation plays an important role in manufacturing industry. The robotic peg-hole insertion operation, the most widely used assembly model, has been heavily studied due to its widespread application. The purpose of the research in this area is to design techniques that enable the robot to perform assembly operations with high speed, high accuracy and low cost. The key problems of strategy investigation research include: (a) designing a series of sub-goals through which the peg-hole system can achieve the insertion operation from any point in the initial area, (b) calculating the allowable range for the initial area, (c) determining the values and duration of the control inputs and (d) analysing the robustness of the strategy. There are many strategies given to perform the assembly operation with the assistance of specially designed force sensors or flexible wrists. In this paper: 1. The map from the position of the peg in the coordinate frame attached to the hole and the location of the contact point in the frame attached to the peg was analysed. This provided the basis for the identification of the position relationship between the peg and the hole using a force sensor signal. 2. The range of peg movement was analysed and found to be useful in the selection of the sub-goals for the insertion operation. 3. A deficient and yet precise hardware strategy, characterized by not requiring force sensors or flexible wrists, was analysed. 4. The validity of the deficient hardware strategy was demonstrated through experiments with the UMI-RTX robot. The results were further confirmed through simulation. The allowed initial area, the control input design and the robustness of the strategy were analysed in detail. A constant cycle time of 2.5 s was achieved during the ten trials in which the diameters of the pegs were selected from a choice of 29.99, 31.98 or 31.99 mm with a clearance between the hole remaining at 0.02 mm and a common peg legnth of 41 mm.

The vibratory alignment of the parts in robotic assembly

2017 ◽  
Vol 44 (6) ◽  
pp. 720-729 ◽  
Author(s):  
Bronius Baksys ◽  
Jolanta Baskutiene ◽  
Saulius Baskutis
Keyword(s):  
Design Methodology ◽  
Robotic Assembly ◽  
Mathematical Approach ◽  
Robot Arm ◽  
Content Type ◽  
Pressing Force ◽  
Passive Compliance ◽  
Alignment Process ◽  
Assembly Operations ◽  
Practical Implications

Purpose This paper aims to consider the experimental and theoretical investigation of the vibratory alignment of the peg-hole, when the peg is fixed in the remote centre compliance (RCC) device, and the vibrations are provided either to the hole or to the peg. Design/methodology/approach The experimental analysis of the circular and rectangular peg-hole vibratory alignment using the attached to the robot arm RCC device, under vibratory excitation of the hole, has been performed. The parameters of the vibratory excitation and the part-to-part pressing force influence on the alignment process have been analysed. The mathematical approach of the vibratory alignment using the passive compliance device with the vibrations provided to the peg has been proposed, and the simulation has been carried out. Findings The research has approved the applicability of the RCC device for both of the vibratory alignments of the non-chamfered peg-hole parts either circular or rectangular ones. The compensation of the axial misalignments has been resulted by the directional displacement of the peg supported compliantly. To perform the successful alignment of the parts, it has been necessary to adjust the frequency and the amplitude of the vibrations, the pressing force, the lateral, as well as the angular stiffness of the device. Research limitations/implications The experiments on the vibratory alignment of the rectangular peg-hole parts have been carried out considering only the translational misalignment moved into one direction. The non-impact regime of the vibratory alignment has been analysed. Practical implications The obtained results can be applied in designing the reliable and efficient devices of the vibratory assembly for the alignment of the non-chamfered peg-hole parts, as well as for chamfered ones, if the axial misalignment exceeds the width of the chamfer. The vibratory technique and passive compliance provide possibility to accomplish the assembly operations using the non-expensive low accuracy robots. Originality/value The new method and the mathematical approach of the vibratory assembly using the RCC device can ensure the reliable alignment of the non-chamfered parts, chamfered circular and the rectangular ones, in case the axial misalignment exceeds the assembly clearance, and prevent jamming and wedging.

Experiments in Local Force Feedback for High-Inertia, High-Friction Telerobotic Systems

2007 ◽  
Author(s):  
Pete Shull ◽  
Gu¨nter Niemeyer
Keyword(s):  
Free Space ◽  
Force Feedback ◽  
Control Structure ◽  
Contact Forces ◽  
Force Sensors ◽  
Frictional Properties ◽  
Dynamic Forces ◽  
Local Controller ◽  
Stable Passive

Many telerobotic systems include a slave robot with much larger inertial and frictional properties than the master robot and/or a non-backdrivable slave acting as an admittance device. Passive controllers, which are known for their stability and robustness, display the large dynamic forces to the user and/or become insensitive to contact forces. In effect, the user feels the large inertia and friction of the slave robot but does not feel the force of the environment. Force sensors can isolate the environment forces. In this paper, we experiment with local force feedback for an admittance type slave robot. We use the local controller to convert the slave to an apparent impedance device, restoring its sensitivity to environment forces. This will allow the application of stable passive teleoperation controllers. The control structure is validated on a single axis of a large, non-backdrivable, industrial Adept robot operating as a slave in contact and in free space.

Fine Motion Strategies for Robotic Peg-Hole Insertion

1995 ◽  
Vol 209 (6) ◽  
pp. 429-448 ◽  
Author(s):  
H Qiao ◽  
B S Dalay ◽  
R M Parkin
Keyword(s):  
Control Area ◽  
Robotic Assembly ◽  
Production Cycle ◽  
Practical Implementation ◽  
Force Sensors ◽  
Real Time Control ◽  
Initial State ◽  
Time Control ◽  
Contact Configuration ◽  
Experimental Trials

The robotic assembly operation has a prominent role in industry due to the fact that (a) it accounts for a substantial proportion of production cycle times and (b) it requires high precision. The peg-hole insertion operation, which is a simplified industrial application model, has special prominence. In terms of the hardware, various complex six-component force sensors, passive compliance and vibration systems have been designed for this purpose alone. In the control area, the disturbance filter and real-time control have been applied to the system to enhance performance. Techniques using geometric concepts such as pre-images and back-projections, models of the contact configurations, pattern recognition and fine motion analysis have been studied. The objective of this paper is to illustrate a method that combines these ideas together to solve practical problems. In this paper: 1. General contact configurations and contact motions between the peg and hole are presented. 2. An important problem in the identification of the contact configuration according to the force sensors is studied. It is concluded that the complete identification of the contact configuration should depend not only on the signals from the force sensors but also on the knowledge about the range of the initial state of the peg and clever utilization of the environment. 3. Various strategies with and without force sensors are proposed. Motion and model analysis is used to study the general identification and motion problems in the peg-hole insertion system. Pre-image and back-projection concepts are employed to enable practical implementation of the method which used Petri nets. Selecting the configuration parameters that can be (a) easily measured and (b) used to decide the incremental motion steps through the procedure were found to be complex and critical tasks that enabled success. These strategies have been verified through experimental trials. It is apparent that the fine motion strategy has a wide application in the robotic peg-hole insertion operation.

Robust contact force estimation for robot manipulators in three-dimensional space

2006 ◽  
Vol 220 (9) ◽  
pp. 1317-1327 ◽  
Author(s):  
J Jung ◽  
J Lee ◽  
K Huh
Keyword(s):  
Contact Force ◽  
Robot Manipulator ◽  
Robot Manipulators ◽  
Dimensional Space ◽  
Three Dimensional ◽  
Contact Forces ◽  
Robust Estimator ◽  
Force Sensors ◽  
Force Estimation ◽  
Estimation Algorithms

Information on contact forces in robot manipulators is indispensable for fast and accurate force control. Instead of expensive force sensors, estimation algorithms for contact forces have been widely developed. However, it is not easy to obtain the accurate values due to uncertainties. In this article, a new robust estimator is proposed to estimate three-dimensional contact forces acting on a three-link robot manipulator. The estimator is based on the extended Kalman filter (EKF) structure combined with a Lyapunov-based adaptation law for estimating the contact force. In contrast to the conventional EKF the new estimator is designed such that it is robust to the deterministic uncertainties such as the modelling error and the sensing bias. The performance of the proposed estimator is evaluated through simulations of a robot manipulator and demonstrates robustness in estimating the contact force. The estimation results show that it can be potentially used to replace the expensive force sensors in robot applications.

scholarly journals Simulation-Based Two Stage Sequencing of Robotic Assembly Operations with Deformable Objects

2021 ◽  
Vol 54 (1) ◽  
pp. 175-180
Author(s):  
Shir Ben-David ◽  
Ran Shneor ◽  
Shahar Zuler ◽  
Zachi Mann ◽  
Alex Greenberg ◽  
...  
Keyword(s):  
Robotic Assembly ◽  
Deformable Objects ◽  
Two Stage ◽  
Simulation Based ◽  
Assembly Operations

Robotic assembly: a synthesizing overview

Robotica ◽  
1987 ◽  
Vol 5 (2) ◽  
pp. 153-165 ◽  
Author(s):  
H. S. Cho ◽  
H. J. Warnecke ◽  
D. G. Gweon
Keyword(s):  
Robotic Assembly ◽  
Assembly Systems ◽  
Mating Speed ◽  
Research Issues ◽  
Flexible Assembly ◽  
Performance Variables ◽  
Assembly Automation ◽  
Dimensional Variation ◽  
Physical Interactions ◽  
Assembly Operations

SUMMARYRobotic assembly systems offer tremendous promise for the flexible assembly automation but present a variety of complex research issues due to the positioning inaccuracy of the manipulator, dimensional variation of mating parts and their physical interactions. This paper provides an up-to-date survey of researches in robotic assembly with emphasis on parts mating technology. Depending upon the mating strategy, presently available methods of performing precision assembly operations are classified and their advantages and limitations are discussed from the view points of the system complexity, adaptability and reliability. The performance variables such as the mating speed, positioning error absorbing capability and applicability are compared in some details for various assembly methods.

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