Showing papers in "Mechatronics in 1996"
TL;DR: In this paper, an advanced continuous path tracking controller and its application to accurate control of two different linear synchronous motor machine tool axes is described, which consists of state feedback, feedforward, and motor ripple compensation.
Abstract: An advanced continuous path tracking controller and its application to accurate control of two different linear synchronous motor machine tool axes are described. The controller consists of state feedback, feedforward, and motor ripple compensation. The feedforward aims at zero tracking errors and consists of inverse model pre-filtering. Ripple compensation is implemented in the position control loop and based on an experimentally identified first order approximation of the motor ripple. Both cogging (magnetic ripple) and force ripple (electro-magnetic ripple) are considered. Experiments carried out on the two machine tool axes show that a simple ripple compensation method is necessary and sufficient in order to achieve acceptable tracking errors.
126 citations
TL;DR: A new type of mechanical guiding system has been designed, based on the use of dynamic constraints; this passive arm is actuated by the surgeon who keeps, therefore, fully involved in the execution of the surgical strategy.
Abstract: Guiding systems for surgical applications range from passive systems to active ones depending on the level of autonomy left to the surgeon. Passive systems provide the surgeon with suitable information to compare the executed strategy with a planned one whilst active systems autonomously perform a part of the surgical strategy. Depending on the selected technology, guiding systems may be more or less accurate, more or less safe, more or less user-friendly. Actuated robots are generally very accurate but raise safety and ergonomics issues; passive systems (optical localizers, motorless encoded arms, etc.) are well-suited to navigation but their use is difficult for executing complex surgical strategies. A new type of mechanical guiding system has been designed, based on the use of dynamic constraints; this passive arm is actuated by the surgeon who keeps, therefore, fully involved in the execution of the surgical strategy. At each instant, the motions proposed by the operator are “filtered” with respect to the task, before being transmitted to the arm. This system seems a good answer to the guided execution of potentially complex strategies in an accurate and ergonomical way. The principles of the PADyC arm are presented and experiments already done with a two-DOF prototype are described.
117 citations
TL;DR: In this paper, a class of robust stable controllers to control the tip position of a multi-link flexible robot is presented. But unlike traditional model-based methods, the controllers are derived by using a basic relationship of system energy and are independent of the system dynamics.
Abstract: A class of robust stable controllers to control the tip position of a multi-link flexible robot is presented. In contrast to traditional model-based methods, the controllers are derived by using a basic relationship of system energy and are independent of the system dynamics. The approach allows controller design in the absence of a system model (which is very complicated in the case of the multi-link flexible robot) and provides great freedom in feedback control design. Further, the controllers are easy to implement in practice because, depending on actual instrumentation, all the signals can be chosen to be measurable. Simulation results of a two-link flexible robot are provided to show the effectiveness of the presented approach.
86 citations
TL;DR: In this article, a robotic seam tracking system is developed to achieve robustness against optical noises such as arc glares, welding spatters, fume, and other unexpected brightness sources.
Abstract: A robotic seam tracking system is developed to achieve robustness against optical noises such as arc glares, welding spatters, fume, and other unexpected brightness sources. The profile data of a weld joint to be welded are reliably extracted using two separate vision processing algorithms: the first is for joint modeling before welding starts, while the second is for joint feature detection during welding. Each procedure is divided into several consecutive steps. In particular, the syntactic approach is refined to improve the reliability of the joint features extracted. To achieve more careful syntactic analysis, several junction primitives and production rules are newly defined. From the joint features thus obtained, the three-dimensional information of the weld joint is extracted to achieve the robot path correction. To investigate the performance of the developed visual system, a series of experiments on joint feature detection and robotic seam tracking are conducted for four different types of weld joints: butt, lap, fillet and vee. The results show that the system is very robust in the presence of various welding noises as well as variations in appearance of weld joint and workpiece.
73 citations
TL;DR: In this article, a theoretically ideal motion profile for point-to-point control under acceleration was derived by adopting Pontryagin's minimum principle, and the performance of this energy efficient motion profile was compared to those of three conventional profiles widely used in practice: trapezoidal, variable-rate transymmetric, and exponential.
Abstract: The motion profile for point-to-point control under acceleration, which is applied to many applications in electro-mechanical systems, should be planned so as to maximize the energy conversion efficiency. Initially, a theoretically ideal profile was derived by adopting Pontryagin's minimum principle. The performance of this energy efficient motion profile is compared to those of three conventional profiles widely used in practice: trapezoidal, variable-rate transymmetric, and exponential. Finally, a selection guide for motion profile is presented for applications in which energy conversion efficiency and peak acceleration become critical, such as the material handling machine, copying machine, various dedicated purpose machines, electric motor cars, and space vehicles.
71 citations
TL;DR: In this article, the authors developed and validated experimentally a model for the description of bone/soft tissue breakthroughs during the penetration of long bones, which can be used for real-time detection of breakthroughs and be included in a mechatronic drill.
Abstract: Among the few motorized procedures used in orthopaedic surgery, drilling is surely the most common. Current drilling tools do not include any means for the control of the penetration and only radiographic control and/or a surgeon's manual skill are used to arrest the penetration of the drill when the hole is completed. Late detection of bone/soft tissue breakthroughs can cause unnecessary damage to the patient. New mechatronic drills making use of cutting force information could be used to assist the surgeon during the intervention. The goal of the experimental study reported is to develop and validate experimentally a model for the description of breakthroughs during the penetration of long bones. Such a model can be used for real-time detection of breakthroughs and be included in a mechatronic drill. Experimental results of drilling trials on fresh animal long bones are presented.
71 citations
TL;DR: The development of a hydraulic gripper with force-feedback which is designed for use in laparoscopic surgery and which exerts a force with a significantly better distribution on the tissue compared to conventional grippers.
Abstract: Telemanipulation for use in surgery is an increasing field of robotics which combines new technical and medical developments. Some drawbacks of minimally invasive surgery can be reduced by using telemanipulation systems. This article describes the development of a hydraulic gripper with force-feedback which is designed for use in laparoscopic surgery. With respect to the manipulation of bowels during a colon resection a gripper is designed which exerts a force with a significantly better distribution on the tissue compared to conventional grippers. This is done by a flexible tube which curls itself around the tissue (like the finger of a surgeon by open surgery) and prevents damaging due to the absence of sharp (metal) edges. The force exerted on the tissue is measured by the pressure of the water in the tube and used to control the driving system of the forceps. Using a computer system, the force exerted on the tissue can be limited to a certain amount by a control algorithm. The driving system consists of an electromotor with spindle and a piston and is driven directly by the computer. Finally, a telemanipulation system is presented, which consists of the hydraulic forceps, a transputer network and a master manipulator with force actuation. With this instrument the surgeon can drive the forceps to a desired force, which is directly presented to his finger. Future developments include the positioning of the gripper inside its working area.
50 citations
TL;DR: Initial results indicate that force feedback could play a major role in the safety protocol of such an invasive system, and the generic vision-guided robotic system for orthopaedic applications described in this paper is typical of this trend.
Abstract: Changes in orthopaedic practice have led to an increased reliance upon fluoroscopic image guidance during internal fracture fixation (osteosynthesis) procedures. The resulting complexity of surgical techniques, and concerns over X-ray radiation exposure levels to orthopaedic surgeons, has prompted the introduction of new technologies into the operating room with the aim of improving the precision, repeatability and radiation safety of existing surgical procedures. The generic vision-guided robotic system for orthopaedic applications described in this paper is typical of this trend. In order to satisfy the stringent safety requirements of robotic-assisted surgery, the mechatronics design philosophy has been applied to the system. A purpose built manipulator has therefore been manufactured, which when interfaced to an existing C-arm unit allows a drill-bit guide to be automatically aligned with an intra-operatively planned drilling trajectory. Manual completion of the drilling stage can then be performed by the surgeon. The preliminary findings of an ongoing study into the potential for an invasive application of such a system, through the use of an actuated drilling unit incorporating a novel use of force feedback, are also presented. Initial results indicate that force feedback could play a major role in the safety protocol of such an invasive system.
48 citations
TL;DR: In this article, an alternative navigation scheme for an outdoor horticultural robot vehicle is proposed, which relies only on local sensing capabilities, without reference to absolute positions; instead the rows of crop themselves are employed as a navigational aid.
Abstract: Possible navigation schemes for an outdoor horticultural robot vehicle are considered. Problems encountered in applying techniques used successfully for industrial Automated Guided Vehicles are highlighted, with particular reference to the problem of finding vehicle position in an absolute Cartesian coordinate frame. An alternative navigation scheme is proposed, which relies only on local sensing capabilities. Demanded paths are specified without reference to absolute positions; instead the rows of crop themselves are employed as a navigational aid. Vehicle position is measured relative to the demanded path. A Kalman filter based algorithm is described which maintains an estimate of vehicle position in this path-relative coordinate frame; input is taken from a machine vision system which is capable of locating crop rows within a video image. This system permits guidance of an experimental vehicle along artificial crop rows at speeds of up to 1.5 ms−1 with an acuracy of ±20 mm.
46 citations
TL;DR: In this paper, an automatically controlled tool is described for the precise drilling of flexible bone tissues during ear surgery, which is able to drill through bone tissue to a surface whose position is unknown.
Abstract: An automatically controlled tool is described for the precise drilling of flexible bone tissues during ear surgery. The micro-drill is able to drill through bone tissue to a surface whose position is unknown. By characterising the tissue from real time drilling data, it is able to stop the drilling as breakthrough starts or to control the drilling to complete the breakthrough with minimum drill bit protrusion by accounting for tissue deflections. Although it is a procedure specific tool, the technique it uses is a generic method of controlling penetration through flexible bone tissues. An aim of the micro-drill is to enhance the skills of the surgeon by utilising sensing and actuation beyond human capabilities. Aspects of the tool design are examined. Some design features result from requirements of the procedure and the human anatomy; others result from the functioning of the tool and the processes used. The overall tool design and operation is reviewed and the requirement for a tool support is considered. A model is used to examine the influence of drill bit shape on the drilling data and its suitability for control purposes. The model is also used to select a feed strategy for the drilling process. It can be seen that these design details are some of the key elements for the effective functioning of the tool.
34 citations
TL;DR: In this article, a more accurate mass matrix was used instead of the constant mass matrix, force derivatives instead of position derivatives were used in the TDC law to reject positional disturbance from the environment, and a novel scheme was adopted to enhance the resolution of A/D conversion for the force sensor.
Abstract: Robot position/force control has been a difficult task owing to the interaction between a robot and the environment. In addition to the dynamic instability, the interaction causes the following problems: (1) the dynamic coupling effect of the robot; (2) positional disturbance due to the uncertain surface of the environment with which the robot is in contact; and (3) vibration at steady state. To solve these problems, time delay control (TDC), well known for its robustness to plant uncertainties and disturbances, has been used as a baseline control law for hybrid control. In conjunction with TDC, the following three ideas were also used. (i) To reduce the dynamic coupling, a more accurate mass matrix was used instead of the constant mass matrix. (ii) To reject positional disturbance from the environment, force derivatives instead of position derivatives were used in the TDC law. (iii) Finally, to reduce the amplitude of the vibration at steady state, a novel scheme was adopted to enhance the resolution of A/D conversion for the force sensor. Experiments showed obvious improvements in the quality of the hybrid control, thereby clearly demonstrating the effectiveness of TDC with the proposed ideas.
TL;DR: In this article, a magnetically levitated wafer transport system was developed for the semiconductor fabrication process to get rid of the particle and oil contaminations that normally exist in conventional transport systems.
Abstract: A new magnetically levitated wafer transport system is developed for the semiconductor fabrication process to get rid of the particle and oil contaminations that normally exist in conventional transport systems. The transport system consists of levitation, stabilization tracks, and a propelling system. Stabilities needed for levitation in the transport system are achieved by an antagonistic property produced in the tracks and using a simple feedback control. The continuous propelling force is obtained by sending specific current patterns to the propulsion coils. The dynamic model of the transport system is presented and analyzed.
TL;DR: The underlying theory and control of a telemanipulator demonstrator is described, together with a discussion of system requirements, and a number of test results are discussed which illustrate the capability of this mechatronics device for use both as a surgeon assistant and as a training aid.
Abstract: The requirements are described of a telemanipulator system for assisting in the penetration of soft tissue for medical tasks. A simulation model of events is required to control the procedure. The same model can also be used by the telemanipulator for training purposes. The underlying theory and control of a telemanipulator demonstrator is described, together with a discussion of system requirements. A number of test results are discussed which illustrate the capability of this mechatronics device for use both as a surgeon assistant and as a training aid.
TL;DR: In this paper, a model reference adaptive control (MRAC) with a nonlinear feedback loop and a disturbance compensation loop is proposed to suppress the nonlinear dynamics of the linkage and external force, respectively, while other feedback loops are designed to achieve the desired specifications.
Abstract: In most machine design, a planar linkage is synthesized to achieve a specific trajectory of motion. However, the dynamics of the planar linkage is shown to be highly nonlinear due to the asymmetry of the geometrical structure and external loads are often present in the output link; thus, the tracking of the prescribed trajectory is difficult to achieve perfectly. A model reference adaptive control (MRAC) with a nonlinear feedback loop and a disturbance compensation loop is proposed to suppress the nonlinear dynamics of the linkage and external force, respectively, while other feedback loops are designed to achieve the desired specifications. Furthermore, switching control is applied to the derivation of the adaptation rule to obtain a satisfactory transient behavior; meanwhile, modifications are proposed to alleviate the chattering due to the switching adaptive mechanism. Experimental studies are performed in a four-bar linkage system to demonstrate the effectiveness of the proposed method.
TL;DR: In this paper, a new six DOF parallel robot which is derived from a classic Stewart platform is presented, which is used as an equestrian simulator and the corresponding control laws have been deduced from data which have been experimentally measured on an actual horse.
Abstract: A new six DOF parallel robot which is derived from a classic Stewart platform is presented The spatial arrangement of the links and the type of actuators, which are hydraulic jacks, induce interesting geometrical and dynamical performances After the description of the mechanical architecture of this robot, the inverse geometrical and kinematical models are presented, along with the control system The robot is used as an equestrian simulator and the corresponding control laws have been deduced from data which have been experimentally measured on an actual horse The gait playback is discussed in the case of the trot, and the interest of the robot so designed is confirmed by the results evaluated by experienced horse riders
TL;DR: In this article, a new Optimum Error Separation Technique (OEST) is described for in-situ measurement of a workpiece without an accurate instrument datum, i.e. without a precise guideway.
Abstract: A new Optimum Error Separation Technique (OEST) method is described for in-situ measurement of straightness of a workpiece without an accurate instrument datum, i.e. without a precise guideway. The goal is to alleviate the deficiencies of the traditional sequential-two-point method (STP) and the sequential-three-point method (STRP). These state-of-the-art techniques must use a sampling interval equal to the sensor spacing which has to be larger than the diameter of the sensors. Such a large sampling interval renders the STP and STRP useless for short workpieces. The new method is established by extending a multi-probe Discrete Fourier Transform (DFT) based roundness measurement method. The aperiodic nature of straightness measurements, which makes the use of DFT inappropriate, is remedied by a numerical search scheme which corrects those data points affected by this limitation. The results of computer simulations and measurement experiments show that this new method is a very good one for short workpiece straightness measurement in an ultra-precision diamond turning lathe.
TL;DR: A learning control architecture using multilayered neural networks is presented and evaluated for trajectory tracking control of robot manipulators which employs a stability-guaranteeing feedback controller (SGFC) which ensures that the tracking error is ultimately bounded.
Abstract: A learning control architecture using multilayered neural networks is presented and evaluated for trajectory tracking control of robot manipulators. This architecture employs a stability-guaranteeing feedback controller (SGFC) which ensures that the tracking error is ultimately bounded. With the help of the SGFC, neural networks can learn to control the robot without fear of instability. Neural networks adjust their weights using the proposed filter-error-learning (FEL) which does not require either desired neural network outputs as teaching signals or error back propagation through the plant. In FEL, teaching signals are extracted from the SGFC, and the learning rule is derived in order to minimize the tracking error. As a result, neural networks learn the inverse dynamics model of the robot. The performance of the proposed learning control architecture is illustrated through simulations with a two-link robot manipulator.
TL;DR: In this article, a variable structure control method for output tracking of uncertain nonlinear systems, with experimental application to an electro-hydraulic servo system, is proposed, where a state transformation is performed to convert the system to the normal form.
Abstract: In this study, we propose a novel variable structure control method for output tracking of uncertain nonlinear systems, with experimental application to an electro-hydraulic servo system. First we perform a state transformation to convert the system to the normal form. Then we apply a method that we have termed provident control, so called because of its frugal but judicious use of the input when compared to other variable structure methods which use large control authority to drive the state to the sliding surface. This method combines variable structure control with variable structure adaptation and performs switching with hysteresis between the structures so as to avoid a sliding mode. By completely separating the reaching and tracking phases, a two-degree-of-freedom controller is obtained. Experimental results indicate significant performance improvement over the well-known boundary layer sliding control, together with robustness against parametric uncertainty and external disturbances.
TL;DR: In this paper, a concept for robotizing the process of winding asymmetric parts based on two manipulating devices, one mandrel manipulator and one payout tool carrier, is presented.
Abstract: Filament winding is one of the most efficient techniques in the manufacture of engineering components from fiber reinforced composite materials. It provides precise distribution of reinforcement into the weaker matrix material, and it lends itself to automation, taking advantage of the recent advances in mechatronics and robotics. A typical robotic filament winding complex (RFWC) integrates design, analysis and manufacturing. It features a specialized CAD/CAM software package for winding pattern generation and analysis of the part to be produced, a mechanical assemblage of winding and handling subsystems with the corresponding control. This paper reports an analysis of some notable existing RFWCs, primarily from the perspective of mechanical design. The conclusions following this analysis have led to the formulation of a novel concept for robotizing the process of winding asymmetric parts which is based on two manipulating devices, one mandrel manipulator and one payout tool carrier. The parameters that influence the conceptual design of RFWCs are discussed, including system configurations, the necessary and sufficient number of degrees of freedom and their distribution within the complexes. Emphasis has been given to process parametrization, structural synthesis and the design of a mandrel manipulator wrist. Two examples are cited to illustrate this new concept.
TL;DR: The design of a novel instrument for the measurement of toothbrushing force applied through the bristle axis using an off-the-shelf hollow-handled toothbrush is presented.
Abstract: The design of a novel instrument for the measurement of toothbrushing force applied through the bristle axis using an off-the-shelf hollow-handled toothbrush is presented. Dental clinicians require to provide toothbrushing instruction and advise their patients to avoid brushing forces that damage the teeth. This instrument allows patient's brushing forces to be measured. Digitised force measurements are captured by a miniature micro-controller and transmitted to a graphics display using a 418 MHz radio transmitter. The adoption of modern microelectronic manufacturing has allowed the toothbrush electronics and power supply to be integrated into an off-the-shelf folding brush handle so that clinical protocols may be conducted unimpeded by the measurement apparatus. A personal computer provides an on-line display of the force-time measurements during toothbrushing. The signal trace is then analysed to extract clinically relevant measurements.
TL;DR: In this article, a precompensation structure, which comprises a linearizer and a stabilizer, is used to modify the dynamics of the robot manipulator so that the standard IMC structure can be implemented without violating its original straightforward and intuitive design principle.
Abstract: The conventional internal model control (IMC) structure commonly used in the process control field is applied for the control of robot manipulators. A pre-compensation structure, which comprises a linearizer and a stabilizer, is used to modify the dynamics of the robot manipulator so that the standard IMC structure can be implemented without violating its original straightforward and intuitive design principle. Analysis of this robot IMC structure reveals that this control algorithm can actually be considered as an enhancement of the conventional robot computed-torque control scheme. Both simulation and experimental results demonstrate that this proposed robot IMC scheme has significantly improved performance as compared with that for the conventional robot computed-torque control algorithm, especially in the presence of modelling uncertainty and external disturbances.
TL;DR: In this paper, an error compensation scheme for the improvement of workpiece roundness error in a diamond turning process is described, which entails an in situ error measurement system, an error separating technique, a piezoelectric micropositioning system, and a P-integrator repetitive controller.
Abstract: An error-compensation scheme for the improvement of workpiece roundness error in a diamond turning process is described. The scheme entails an in situ error measurement system, an error separating technique, a piezoelectric micro-positioning system, and a P-integrator repetitive controller. The scheme is realized on a diamond turning lathe and demonstrates the reduction of the roundness error by more than an order of magnitude in real machining.
TL;DR: In this article, a two-degree-of-freedom spring-lumped mass system sliding on a guide pillar, with two internal vibration disturbance sources, was designed and constructed.
Abstract: The design and construction of a dynamic absorber incorporating active vibration control is described. The absorber is a two-degree-of-freedom spring-lumped mass system sliding on a guide pillar, with two internal vibration disturbance sources. Both the main mass and the secondary absorber mass are acted on by D.C. servo motors to suppress the vibration amplitude. A fuzzy control algorithm is used to control this multi-input/multi-output (MIMO) system. According to the characteristics of the system dynamics, the membership fuctions and the fuzzy rules are decided. Then a conventional fuzzy controller and a decoupling fuzzy controller for the MIMO vibration system are designed. Finally, the results of some experiments are presented. The experimental results show that the system is effective in suppressing vibration. The performance of this control strategy for position tracking control is evaluated based on experimental data.
TL;DR: In this article, the effect of machining imperfections like out-of-roundness and taper in the piston on the mechanical and volumetric efficiency of the motor, in the speed range where the viscous friction is dominant, is studied.
Abstract: Axial piston motors rely on a close fit of piston to bore to minimise leakage past the piston due to axial pressure drop. Machining imperfections in the cylinder bore and the piston change the clearance between them, affecting the performance of the motor. The effect of machining imperfections like out-of-roundness and taper in the piston on the mechanical and volumetric efficiency of the motor, in the speed range where the viscous friction is dominant, are studied. Experiments to measure torque and leakage flow are conducted on a fixed displacement swash plate type axial piston hydraulic motor and results are presented.
TL;DR: In this article, a study on the kinematics, dynamics and control algorithms for a three-joint revolute manipulator is conducted, where the acceleration and velocities of the manipulator are modeled as different from those used in conventional manipulators.
Abstract: The advent of supermaneuverable flight trajectories for high performance aircraft initiates new research areas involving human factors' effects on pilots when they fly these unusual flight scenarios. This institutes a need to conduct studies in motion simulators such as centrifuges to investigate how these unusual motion fields affect humans' physiology and how they influence the ability of a pilot to perform a mission. A study is conducted on the kinematics, dynamics and control algorithms for a centrifuge motion simulator. The centrifuge is modeled as a three-joint revolute manipulator. Algorithms for solving the joint velocities and joint accelerations are quite different from those used in conventional manipulators. In order to command the end effector (or the seat in the centrifuge) to follow the prescribed trajectory, various optimal control algorithms are studied and control laws based on the concepts of feedback linearization are derived for the motion control of the centrifuge.
TL;DR: In this paper, a generalized calibration method and an exact 3D range data extraction algorithm for an omnidirectional laser range finder are described, which roughly transforms a point on a 2D image plane into a position in a 3D spatial coordinate system.
Abstract: A generalized calibration method and an exact 3D range data extraction algorithm for an omnidirectional laser range finder are described. Firstly, a simple 3D range data extraction is achieved by ignoring the camera's lens distortion and scale factor, using the focal length as it is given by the manufacturer, and introducing some assumptions. The simple extracting equations roughly transform a point on a 2D image plane into a position in a 3D spatial coordinate system. Secondly, the intrinsic parameters of the CCD camera are obtained by an existing camera calibration method based on a pin-hole camera model. Thirdly, the exact design constant of the laser slit emitting device and the extrinsic parameters of the CCD camera are simultaneously obtained by laser range finder calibration, where the previously obtained simple 3D range data extraction equations are modified exactly. Consequently, the simple 3D range data calculation equations can be expanded to the exact one by using the parameters obtained by camera and laser slit emitting device calibration. Finally, the calibration parameters and the exact 3D range data of an omnidirectional laser range finder are obtained by experiment and errors of the measurement distances are calculated.
TL;DR: The main focus of this paper is on the design of a system that combines the Texas Instruments TMS320C30 floating-point DSP with a parallel processing system based on Intel i860 RISC processors and Inmos transputers to achieve excellent real-time response and superior computational power.
Abstract: A system for implementing an advanced motion controller using a floating-point digital signal processor (DSP) and a transputer-based parallel processing system is presented. The discussion includes a brief look at the advantages of using DSPs in real-time control applications and the architecture for integrating DSPs with parallel processing transputer networks to enhance computing power. The main focus of this paper is on the design of a system that combines the Texas Instruments TMS320C30 floating-point DSP with a parallel processing system based on Intel i860 RISC processors and Inmos transputers to achieve excellent real-time response and superior computational power. The software of the system is hosted in the popular MATLAB program which furnishes a simple user interface and programming environment. The system is ideal for implementing advanced motion control experiments that require high-speed floating-point computations as well as fast sampling rates. In addition to real-time experiment, the system also includes a simulation package to allow rapid verification of the user's program and control algorithm. A complex adaptive motor control experiment is presented to illustrate the application of the system.
TL;DR: In this paper, the use of the natural modes of oscillation for efficient performing of complex space motions of a robot with changeable parameters and dynamically interacting degrees of freedom is discussed.
Abstract: The use of the natural modes of oscillation for efficient performing of complex space motions of a robot with changeable parameters and dynamically interacting degrees of freedom is discussed. For the realisation of high-speed motions in these conditions under the limitation of control torques, it is necessary to identify at first, through on-line analysis of motions in the process of manipulation, the real parameters of natural modes. Then the control torques should be brought into correlation with natural motions by the adaptation of control in accordance with the findings of identification. As a result, the processes of identification, adaptation and control have to be optimised in accordance with the dynamics of robot oscillation. The formulated concept is demonstrated by research and development of an adaptive high-speed manipulator MARS-3 realised by the above mentioned principles for operating in cylindrical co-ordinates.
TL;DR: In this article, a series of simulations and experiments are performed; the results show that a better simulation result can be obtained if the relief valve characteristics are considered in the system model, and adverse influence of relief valve on the performance of the pump or inverter controlled hydraulic motor system can be avoided if a self-tuning adaptive controller is employed.
Abstract: The influence of the relief valve, which is used as a safety valve, on the performances of a pump/inverter controlled hydraulic motor system is discussed. The mathematical models are derived, and then the optimization technique is used to identify the system parameters. A series of simulations and experiments are performed; the results show that a better simulation result can be obtained if the relief valve characteristics are considered in the system model, and adverse influence of the relief valve on the performance of the pump or inverter controlled hydraulic motor system can be avoided if a self-tuning adaptive controller is employed.