| In the more than half century since the emergence of industrial robots,robotics technology has developed from the initial automation to the now-enhanced intelligent stage,playing an increasingly important role in manufacturing,service,national defense and aerospace,representing a country's core competitiveness.In order for robots to become effective collaborators,robots must be able to reliably perform complex interactions in dynamic,unstructured environments designed for humans.So far,however,even the most advanced robots have been slower,if not very reliable,than humans in carrying out such constrained tasks.This scientific problem has attracted the attention of a large number of domestic and foreign research institutions.If the problem of robot interaction and compliance control in the unstructured dynamic environment can be fundamentally solved,the physical constraints between intelligent robots,machines and human beings will be broken,so that robots can become effective collaborators of human beings and achieve “co-existence".(1)The framework of robot contact interaction compliance control is studied.The construction of robot dynamics model and contact dynamics model is the basis for the study of compliance control,and also the premise for the study of many key problems in the interaction system between robot and physical environment.On the basis,the classical compliance control principle and implementation method are studied,and the robot compliance control framework is constructed based on the mathematical model,physical model and control principle of robot compliance contact interaction.(2)The principle of adaptive impedance control based on dynamic update rate is studied.An adaptive hybrid impedance control strategy based on dynamic update rate is designed to solve the dilemma that the adaptive hybrid impedance control scheme could not simultaneously control the contact overshoot and accurately track the robot in the contact force control task.The transient system response behavior and steady-state tracking performance of the impedance controller are analyzed and the update rate dynamic adjustment method is designed.The stability and boundary conditions of the impedance controller are analyzed,the necessary conditions to ensure the stability of the system are expounded,and the control effect of the control strategy is verified by simulation.(3)The principle of adaptive impedance control based on PID and fractional order composite enhancement effect is studied.In order to further improve the performance of the adaptive impedance control,the impedance control strategy is improved by using the combination of two control tools based on the pre-PID and fractional order.By introducing the front PID controller to change the natural frequency of the system,the impedance controller has a faster response capability.The dynamic adjustment problem caused by the expansion of update rate boundary caused by the front PID is analyzed,and the update rate is inferred online by fuzzy logic control.The stability and robustness of the impedance controller are improved by introducing fractional order calculation tool,so that the controller can suppress the contact hyper harmonic vibration more effectively.For the complex calculation problem caused by fractional order impedance control,the percentage coefficient is designed to simplify the calculation and realize the conversion from fractional order to integer order without affecting the control effect.The control effect of the control strategy is verified by simulation.(4)The principle of dynamic adaptive switching impedance control based on sensor-execution mode is studied.Based on the analysis of the dynamic physical characteristics of the robot impedance control strategy for the adaptation to the environment,and the inspiration of the integration of ants and the environment in nature,the function and behavior characteristics of the robot were bionic,and the adaptive switching hybrid control strategy based on the sensor-execution mode was designed to realize the flexible interactive control of the robot in the unstructured dynamic environment.Firstly,an environmental self-sensing detection device with no force,displacement or other sensors is designed with an integrated sensor-execution function similar to that of the ant antenna.The environmental characteristic parameters are identified online through the self-sensing circuit and estimation algorithm.An adaptive signal separation algorithm is designed to compensate for the lack of measurement accuracy caused by the circuit bridge measurement method.Secondly,the hybrid impedance control strategy is designed by comparing the tracking performance difference between the dynamic and location-based impedance control based on the adaptability to different characteristic environments.The stability of the hybrid controller in the switching process is analyzed.Finally,in view of the unstructured dynamic environment parameters,such as nonlinear stiffness mutation caused by exposure to overshoot problem,through the establishment of contact with the process of energy dissipation and transformation model,elastic moderate controller is designed in the stiffness mutation position switch of expectations suppress this extremely damaged contact overshoot behavior,optimize the dynamic switching control parameters were analyzed,and guarantee the stability of the parameters when switching system.(5)Experimental study of robot compliance contact interaction control strategy is presented.The robot motion control system based on the field industrial bus and CODESYS runtime is constructed with the features of expandable function modules and full openness,and the experimental research on the contact and interaction between the robot and the unstructured dynamic environment is carried out.An unstructured dynamic support environment is constructed and the effectiveness of the flexibility strategy proposed in this paper is verified by experiments. |
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