比例積分微分控制器外文翻譯-展示頁
2025-05-26 13:21本頁面
【正文】 must be reduced so that the control system does not overshoot, oscillate or hunt about the control setpoint value. The control system performance can be improved by bining the feedback (or closedloop) control of a PID controller with feedforward (or openloop) control. Knowledge about the system (such as the desired acceleration and inertia) can be fed forward and bined with the PID output to improve the overall system performance. The feedforward value alone can often provide the major portion of the controller output. The PID controller can then be used primarily to respond to whatever difference or error remains between the setpoint (SP) and the actual value of the process variable (PV). Since the feedforward output is not affected by the process feedback, it can never cause the control system to oscillate, thus improving the system response and stability. For example, in most motion control systems, in order to accelerate a mechanical load under control, more force or torque is required from the prime mover, motor, or actuator. If a velocity loop PID controller is being used to control the speed of the load and mand the force or torque being applied by the prime mover, then it is beneficial to take the instantaneous acceleration desired for the load, scale that value appropriately and add it to the output of the PID velocity loop controller. This means that whenever the load is being accelerated or decelerated, a proportional amount of force is manded from the prime mover regardless of the feedback value. The PID loop in this situation uses the feedback information to effect any increase or decrease of the bined output in order to 無 錫 職 業(yè) 技 術(shù) 學(xué) 院 外文翻譯 4 reduce the remaining difference between the process setpoint and the feedback value. Working together, the bined openloop feedforward controller and closedloop PID controller can provide a more responsive, stable and reliable control system. Another problem faced with PID controllers is that they are linear. Thus, performance of PID controllers in nonlinear systems (such as HVAC systems) is variable. Along with the development of Fuzzy Mathematics, control engineers gradually pay much attention to the idea of Fuzzy Control, thus promoting the inve
畢業(yè)設(shè)計相關(guān)推薦
鄂ICP備17016276號-1