Modeling and Precise Position Control of Flexible Joints with Harmonic Drives

Abstract This paper presents the development of a six degrees-of-freedom manipulator with soft end-effector and an inverse kinematic compensator for aerial contact manipulation. Realizing the fact that aerial manipulators can hardly achieve precise position control, a compliant manipulator with soft end-effector is first developed to moderate end-effector positioning errors. The manipulator is designed to be rigid-soft combined. The rigid robotic arm employs the lightweight but high-strength materials. The compliance requirement is achieved by the soft end-effector so that the mechanical design for the joints are largely simplified. These two features are beneficial to lighten the arm and to ensure the accuracy. In the meantime, the pneumatic soft end-effector can further moderate the probable insufficient accuracy by endowing the manipulator with compliance for impact resistance and robustness to positioning errors. With the well-designed manipulator, an inverse kinematic compensator is then proposed to eliminate lumped disturbances from the aerial platform. The compensator can ensure the stabilization of the end-effector by using state estimation from the aerial platform, which is robust and portable as the movement of the platform can be reliably obtained. Both the accuracy and compliance have been well demonstrated after being integrated into a hexarotor platform, and a representative scenario aerial task repairing the wind turbine blade-coating was completed successfully, showing the potential to accomplish complex aerial manipulation tasks.

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Precise position control of tubular linear motors with neural networks and composite learning

Control Engineering Practice ◽

10.1016/j.conengprac.2010.01.013 ◽

2010 ◽

Vol 18 (5) ◽

pp. 515-522 ◽

Cited By ~ 44

Author(s):

David Naso ◽

Francesco Cupertino ◽

Biagio Turchiano

Keyword(s):

Neural Networks ◽

Position Control ◽

Precise Position ◽

Linear Motors

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LOOKING FORWARD TO THE INTELLIGENT ELECTRICAL MACHINE: ELECTRONICS AND MACHINES COMBINE THEIR ABILITIES

Journal of Circuits System and Computers ◽

10.1142/s0218126695000059 ◽

1995 ◽

Vol 05 (01) ◽

pp. 45-63

Author(s):

DIETRICH NAUNIN

Keyword(s):

State Feedback ◽

Position Control ◽

Controller Design ◽

Supply Voltage ◽

Induction Machine ◽

State Feedback Control ◽

Electrical Machine ◽

Precise Position ◽

Electric Cars ◽

Drive Systems

Electrical machines, more than 150 years old, have long been distinguished according to their mechanical structure and frequencies of their supply voltage (or current). This is not true any more after the electronic revolution. Since the fast development in power electronics as well as in control electronics these electronics can give any motor any desired speed-torque characteristic and any motor can become a servodrive having a very precise position control. By implementing digital control algorithms, mainly the cascaded, the state feedback or the cascaded state feedback control, and — if necessary, in addition — adaptive control procedures which compensate the variation of system parameters in the controller, the "intelligent electrical machine" — either with the synchronous or with the induction machine — is created. It is part of mechatronics. It can be installed in modern automated systems, in robots and tool machines, in all kinds of industrial drive systems as well as in locomotives and electric cars. Also modern methods like fuzzy logic and neural networks can be used. It seems that they will not create a second revolution in the control itself, but in the application areas of drives. They add some interesting features to the intelligent electrical machine and make it even more intelligent. They could also speed up the controller design in future.

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A Modified Predictive Functional Control With Sliding Mode Observer for Automated Dry Clutch Control of Vehicle

Journal of Dynamic Systems Measurement and Control ◽

10.1115/1.4032830 ◽

2016 ◽

Vol 138 (6) ◽

Cited By ~ 11

Author(s):

Liang Li ◽

Xiangyu Wang ◽

Xiaosong Hu ◽

Zheng Chen ◽

Jian Song ◽

...

Keyword(s):

Position Control ◽

Sliding Mode ◽

Sliding Mode Observer ◽

Load Torque ◽

Nonlinear Load ◽

Precise Position ◽

Predictive Functional Control ◽

Functional Control ◽

Dry Clutch ◽

Clutch Control

Dry clutch control is a typical nonlinear problem due to the nonlinear characteristics of diaphragm springs. For precise position control of the automated dry clutch, a modified predictive functional control (mPFC) method is proposed. First, a novel mechanical actuator is designed and models of the automated dry clutch system are built based on theoretical analysis and experimental data. Then, in order to compensate for the position error of direct current (DC) motor caused by load torque, modifications are introduced to a regular predictive functional control (PFC), including a sliding mode observer (SMO) to estimate the load torque and a predictive model concerning the load torque. Next, simulations show that the SMO could estimate the load torque accurately and the mPFC performs well with the nonlinear load torque. Finally, experiments are carried out on a test bench and the results are in accordance with the simulations. Due to the little online computing burden and the simple structure of the mPFC, it could be used in other industrial control systems which need fast response.

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