Integrated Design Of Active Torque Balancer And Speed Reducer

Input torque balancing is a traditional subject in mechanical dynamics. The existed balancing methods include passive balancing methods and active balancing methods. The passive balancing methods reduce the input torque fluctuations through optimizing internal parameters of the mechanisms. The active balancing methods minimize the input torque fluctuations by adding different types of balancing devices. In these approaches, mounting a flywheel is the simplest one and is widely applied in industry. However, a large flywheel is usually needed, and the start and stop behaviors of the mechanism may be influenced or compromised. Besides, since they have no abilities of adjusting themselves to meet the requirements of variable working conditions or different working mechanisms, and their structures are inconvenient to implemented, the other balancing methods can hardly be spread to the industry. The active control balancing methods, which appear recently, have good manners in flexibly improving the dynamic characteristics of machines. In this dissertation, through considering the existed balancing methods can hardly be spread to the industry, a novel concept of integrating both the structures and functions of active torque balancer which can actively balance the torque fluctuations of machines and speed reducer which is an indispensable device of machines is proposed. This new concept inherits the strongpoint of the active control methods, and is expected to promote the industry application of the torque balancing technique.According to the increasing levels of being integrated with the speed reducer, four new concept devices are proposed and introduced in this dissertation. They are independent in structure that can be assembled and disassembled conveniently. While balancing the input torque fluctuation and/or reducing the driving speed, they will not influence the desired kinematics characteristics of the mechanisms.First of all, the output shaft type active torque balancing device using servo-controlled differential gear train (OATBD), which is composed of a differential gear train and a servomotor and installed on the output shaft of the working mechanism, is introduced. Since it is independent with the speed reducer, the integrated level of it is on the first class, that is, the lowest class. Firstly, the concept design of the OATBD and the analysis of torque balancing principle are carried out. Secondly, two optimization approaches for selecting appropriate input functions of the servomotor and choosing suitable structure parameters of the differential gear train are developed. Thirdly, learning control theory is validated to be an effective approach in controlling the servomotor to minimize the input torque fluctuation. Fourthly, numerical examples are given to illustrate the design procedures and to show their feasibilities.Besides, the input shaft type active torque balancing device using servo- controlled differential gear train (IATBD), which is composed of a differential gear train and a servomotor too and assembled on the input shaft of the working mechanism, is introduced. Since it shares a common shaft with the speed reducer, its integrated level is on the second class. Firstly, the concept design of the IATBD and the analysis of torque balancing principle are carried out. Secondly, three optimization approaches for selecting appropriate input functions of the servomotor and choosing suitable structure parameters of the differential gear train are developed. Thirdly, learning control theory is validated to be a feasible approach in controlling the servomotor to minimize the input torque fluctuation. Fourthly, numerical examples are given to illustrate the design procedures and to show their feasibilities. Fifthly, the experimental platform of the IATBD is manufactured and its initial examination is implemented.What's more, the servo-controlled differential gear train integrating torque balancing and speed reduction (SDGT), which is composed of the torque compensation unit and the speed reduction unit, is introduced. In this device, the torque compensation unit which consists of a differential gear train and a servomotor is used to balance the torque fluctuation of the mechanism; the speed reduction unit which is composed of a two-stage planetary gear train is applied to meet the requirement of the speed ratio. Since both the speed reduction unit and the torque compensation unit are integrated together as an entire device, its integrated level is on the third class. Firstly, the concept design of the SDGT and the analysis of torque balancing principle are carried out. Secondly, three optimization approaches for selecting appropriate input functions of the servomotor and choosing suitable structure parameters of the differential gear train are developed. Thirdly, learning control theory is validated to be an effective method in controlling the servomotor to minimize the input torque fluctuation. Fourthly, numerical examples are given to illustrate the design procedures and to show their feasibilities.Additionally, the non-circular gear device integrating torque balancing and speed reduction (NGD), which is composed of a two-stage non-circular gear transmission, is introduced. Since its abilities of speed reduction and torque balancing are fused together that it is hard to distinguish which part is used to balance the input torque and which part is used to reduce the driving speed, its integrated level is on the fourth class, that is, the highest class. Firstly, the concept design of the NGD and the analysis of torque balancing principle are carried out. Secondly, a design method for optimizing the transmission functions of the noncircular gears independently and a design method for optimizing both the moment of inertia of the variable-speed shaft and the transmission functions concurrently are developed successively. Thirdly, numerical examples are given to illustrate the design procedures and to show their feasibilities. Fourthly, the prototype of the NGD is manufactured and its initial examination is implemented.Just like a speed reducer, the proposed devices are convenient in application and independent in structure. While balancing the input torque fluctuation and/or reducing the driving speed, they will not influence the desired kinematics characteristics of the mechanisms. Furthermore, through using the servo-controlled system, OATBD, IATBD and SDGT are universal in mechanism and flexible in compensating the torque fluctuations. When the working mechanism is changed by another one, or the external working condition of machine and/or the internal structure parameters of machine are changed, they can actively balance the torque fluctuations all the same. The NGD is a pure mechanical device. While fulfilling the design requirement of speed ratio, it can take advantage of the speed fluctuating effect which is actively generated by two pairs of non-circular gears to balance the input torque of the mechanism.This dissertation presents a novel concept of integrating the active torque balancer with the speed reducer, and the proposed new concept may be able to provide a new technical way for spreading the engineering application of the torque balancing methods.