| Teleoperation systems with master-slave robots at the core can becomplex manipulated in uncertain or extreme environments (such as space,seabed, radialization, battlefield, etc.). The quality of operation iscorrelation with the ability of getting information (such as force,vision, etc.) about the slave side. The dynamic reciprocity betweenrobots and operated objects can be felt by teleoperation system onaccount of the force telepresence and vision telepresence,which make theoperator accomplish complicated and exact operation. Nowadays theresearch of technology related to telepresence is gaining greaterattention.Vision telepresence can provide most information for teleoperations,it is of great help for the human operators' cognition to the environmentsbeing operated. When robots contact the environment and only visiontelepresence is provided, human operators cannot acquire the real sense.Only with the guidance of force telepresence can human operatorsaccomplish these complex and fine tasks. Experiments on teleoperationsystems also indicate that force and tangency senses can greatly enhancethe efficiency and accuracy of teleoperation systems. Due to these, forcetelepresence may provide great help for teleoperation systems, and itcan greatly enhance manipulation performance. of following inmaster-slave position control, we have brought forward a new bilateralservo control scheme and studied out experiment scheme.The rationality of the position controller is validated through theexperiment of master-slave position control. And the feasibility of thecontrol scheme and the validity of force controller are validated throughthe experiment of force feedback.Combining the researches of theory and experiments, we haveaccomplished the main research tasks as follows:1. We have set up a single-DOF telerobot system with force feedbackbased on electron hydraulic servo control system and it has the capacityof teleoperation, high precision position control and force feedback.The establishment of this system and the application of new bilateralservo control strategy provide practice according for establishment ofcomplicated teleoperation system and basis for researches of bilateralservo control strategy.2. We have designed single-DOF master controller and slavecontroller based on electron hydraulic proportional control. In orderto get favorable dynamic and static performance for the hydrauliccylinders, we have designed PID serial correction controller and got theparameters of the controllers through the method of 2-rank engineeringdevise. We have realized high accurate position control through thedesignation of master controller. We have realized force telepresencethrough the designation of slave controller. Applying the newforce-position bilateral servo control algorithm advanced in this paper,with the difference between the force of the master and slave systemsbeing the controlling signal which controls the movement of the hydrauliccylinder in the slave system, we have made the displacement of thehydraulic cylinder in the master system follow accurately that in theslave. This new bilateral servo scheme is validated to have perfecteffect in master-slave position control and force feedback. Thisstrategy can make human operators grasp not only the moving status ofthe slave but also the interference of it, while the working resistancecan be sensed at the same time. And it can also eliminate the strike inforce feedback to some extend.3. The research and development of bilateral servo controlstrategies have been introduced in detail. By compares of workingcharacters of the three bilateral servo control strategies in both motorand electron hydraulic controlled robots, especially the mendedbilateral servo control strategies and the problems existed in thebilateral servo control of the latter. And the new bilateral servocontrol strategy.In this paper, we have set up a telerobot system hydraulically drovedwith force feedback which is called single-DOF bilateral servo systemafter analyzingthe telerobot systems with telepresence, especiallythose with force telepresence in home and abroad. The system has asymmetrical structure, whose master and slave subsystem is the same inform. To speak of the function of this robot system, it mainly compriseselectron hydraulic proportional control subsystem, bilateral servocontrol subsystem. We have discussed the structures and realization ofthe functions of all subsystems at length built on those mentioned above.Aimed to the characters of the telerobots under electron hydraulicservo control, we have researched the traits of the hydraulic system andcomparatively analyzed the typical bilateral servo control strategies.As to the problem of force feedback existed in teleoperation systemsunder the complex control of force and position such as the greatnessof the strike in force feedback and the bad capabilityis refereed to inbrief.4. Aimed to the control request of this master-slave robot systemwith force feedback, we have accomplished the software designation forbilateral servo control. As to the strict real-time characteristic ofthis bilateral servo system which uses one PC to gather data and calculatecontrol data, we have discussed the key technology of multithread, VxD(Virtual Device Driver), interruption which are applied in Windows98operating system. VtoolsD 3.0 is used to develop VxD programmes whichrealize not only the initialization of hardware, such as A/D card andD/A card, but also the settings of data collection and interruption.VC++6.0 is used as the development tools for multithread programmes toaccomplishdata processing and output control signal which finally realize servocontrol.The control computer gathers position and force signals every times,and calculates the position control signal by the bilateral algorithm.This process can be described as follows at length: The PC first gathersthe force signals from both the master and slave system. Aftercalculating the difference between the two which is used as the controlsignal, the PC outputs the corresponding control signal using forcecontrol algorithm to the electron hydraulic proportional controller todrive the hydraulic cylinder in the slave system. At the same time, thehydraulic cylinder in the master system follows accurately the movementin the slave. Depending on all these, we have realized high precisioncontrols of both the position and force. With the new bilateral strategy,this master-slave robot system achieves favorable control effect.The researches in the paper are aimed to electron hydraulic servotelerobot system with force feedback, which uses new bilateral servocontrol strategy. With this new bilateral servo strategy applied inmaster-slave robot systems and high prompts by force telepresence, whichcan make human operators perceive veritably the dynamic reciprocitybetween the robots and environment, telerobot systems can accomplishcomplex tasks under inaccessible environment. The researches on controlstrategy and experimentations in this paper provide experience and keytechnology for teleorobot systems' utilities, and as a result they willgreatly enhance work efficiency in teleoperations. |
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