Flexible mechanical arm system high-order sliding mode anti-interference control method

Abstract

The invention discloses a high-order sliding mode anti-interference control method for a flexible mechanical arm system, which is suitable for high-precision position control of the flexible mechanical arm system.The method comprises the steps that firstly, a dynamic model of a flexible mechanical arm is established according to a flexible mechanical arm structure, and motor side dynamics and connecting rod side dynamics are considered at the same time; introducing backlash nonlinearity and model uncertainty of the mechanical arm into the mechanical arm dynamic model as external disturbance, and establishing a flexible mechanical arm four-order dynamic model; aiming at non-matching disturbance existing in a high-order system, designing an extended state observer to estimate unknown disturbance in real time, and on the basis, designing a high-order sliding mode controller and compensating the non-matching disturbance; the high-order sliding mode controller based on the extended state observer is designed for the situation that the high-order sliding mode controller has large fluctuation of the control quantity near a balance point, the fluctuation amplitude of the control input quantity is reduced on the premise that the position tracking performance of a mechanical arm system is guaranteed, and application in engineering practice is facilitated.

Description

technical field [0001] The invention relates to the technical field of flexible manipulator systems, in particular to a high-order sliding mode anti-interference control method of a flexible manipulator system. Background technique [0002] With the increasing number of collaborative work between robots and humans, the safety of robots has also become a hot issue. The manipulator has also been developed from a traditional rigid manipulator to a flexible manipulator. In order to achieve the flexibility of the manipulator joint, an elastic element can be connected in series in the manipulator joint transmission chain to form a series elastic actuator (SEA). Compared with traditional rigid robots, flexible joint robots have smoother force transmission and greater energy transmission efficiency. However, in practical applications, due to the existence of joint flexibility, the torque on the joint will cause elastic deformation of the joint elastic brake, resulting in the moveme...

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Problems solved by technology

If the traditional PID control is adopted, the control effect is difficult to meet the control requirements due to the elastic connection between the motor side and the connecting rod side, and inaccurate modeling. Interference and system uncertainty have the advantages of strong robustness, and are widely used in practical engineering systems. Literature (Feng Y, YuX, Man Z.Non-singular terminal sliding mode control of rigid manipulators[J].Automatica ,2002,38(12):2159-2167.) For second-order systems with uncertain parameters such as manipulators, a non-singular fast terminal sliding mode control method was proposed, and the stability of the controller was proved by using the Lyapunov function

However, sliding mode control cannot estimate structural uncertainties such as parameters in the system, while active disturbance rejection control can treat external disturbances and parameter uncertainties of the system as lumped disturbances, and estimate them through the extended state observer , and compensate at the controller side, so as to improve the anti-disturbance performance of the system, the literature (Ren C E, Du T, Li G, et al. Disturbance observer-based consensus control for multiple robotic manipulators [J]. IEEE Access, 2018, 6: 51348-51354.) For robot systems with unknown disturbances, a control strategy combining sliding mode and disturbance compensation is proposed, which improves the robustness and anti-disturbance ability of the system

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