Force Estimation Strategy for Force Feedback Joystick Based on Improved Stribeck Friction Model

Abstract:

In the process of traditional force feedback joystick interacting with people, force sensors are relied on to measure the operating force. However, installing force sensors significantly increases the user?s operational burden and raises the manufacturing cost of the force feedback handle. To alleviate the user?s operational burden and reduce manufacturing costs, a force estimation strategy was proposed for a two?degree?of?freedom force feedback joystick based on an improved Stribeck friction model. A model was established to describe the handle?s dynamics. The improved Stribeck model was used to characterize the nonlinear friction in the joystick?s dynamics model. The traditional Stribeck friction model was analyzed, and improvements were made to address the problem of abrupt changes in frictional force when the velocity switched between positive and negative zero points. Experiments were designed to identify the parameters in the model equations, considering the characteristics of the joystick system. The least squares method was used to fit curves of the system?s gravity and friction parameters to determine the corresponding parameters. Based on the identified parameters, the force at the joystick?s end was estimated. Experimental results showed that the estimated force was basically consistent with the actual data, verifying the accuracy of the proposed force estimation strategy.