Research And Model Of Friction Drive Theory Based On Stick-Slip Effect

Large range micro-manipulator is still on experiment, without many successive prototypes. The low drive force, low precession, and low stability are the biggest obstacle to the application. However, all the defections are the result of the lack of study on the drive principle. To solve the problem, the best way is make a better model to analysis the factors which affect the movements, by which it's easier and more reliable to get the stability and the control strategy.The drive principle of the spherical manipulator based on friction is studied, and simplified to be a two-mass oscillator model, though which The dynamics characters, optimization, frequency respond, and the control strategy is studied.Firstly, based on the former experiment, the investigation is on the dynamic characters of the friction drive principle. The dynamics model is made up to numerically study the movement caused by the friction drive principle. Then, the movement is divided into basic vibration state and micro vibration when the state changes according to the simulation to demonstrate the cause of the movement of friction drive. The definition of the movement is composed by the forced vibration and self-excited vibration is presented, and verified.Then, the phase-space equations is presented based on the two-mass-oscillator dynamic equations, taking the relative velocity as the factors, to get the criterion as how to distinguish the stick phase and slip phase, which give a great convenience to optimize the design, and stability and control strategy.The response is studied following. The common solution is given based on the harmonic balance method, numerical method and optimization theory; the two-mass-oscillator model is analysed in MATLAB, both coincide with each.In the end, the stability is discussed under the Coulomb friction model, getting the normal force compensation method and the additive vibration control method, which are to stabilize the friction drive system to realize the controllability and stability, which is simple to realize in the micro manipulator.