無段変速機を用いたある巻取制御系の解析とその設計への応用

Bang-bang control systems, the manipulating device of which is composed of a mechanical variable speed drive, are widely used as take-up devices, in order to control the speed and the tension of running materials. This type of control system has a disadvantage that the hunting in system response is likely to occur, because of the use of a weighted dancer roller and of the bang-bang action of the three-positions relay. The authors have tried to improve the performance of the control system by using a spring dancer roller having faster response property and a servo-mechanism combined with a DC-servo-motor and SCR-amplifier. The performance of the control system has been analysed in order to get enough knowledge for the control system synthesis. Thus the synthesis of the control system has been accomplished, both keeping the variation of take-up tension of the running material lower and making the response faster.<BR>In Part 1, the dynamic characteristics of the control system mentioned above were analysed ; the condition of critical damping, of self-sustained oscillation and of instability. The main conclusions obtained are : <BR>1) The condition of critical damping is expressed as a function of the loop-gains A, B and of the time constant T₂ of the actuator.<BR>2) The condition of self-sustained oscillation for the control system without back-lashes, is given by<BR>A= (T₁+T₂) B<BR>where T₁ is the time constant of a servo-motor, For the control system with back-lashes, the effect of backlashes on the above condition can be replaced by the increases of the time constants in the above equation, and result in the increase of the critical loop-gain Ain the same equation.<BR>3) The stability criterion for the actual system having nonlinear elements is almost the same as that for the linear system obtained by ignoring these elements.