基于改进Stribeck摩擦模型的力反馈手柄力估计策略

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

摘要:

传统力反馈手柄在实现与人交互过程中，依赖于力传感器测量操作力。而力传感器安装会大大增加操纵负担，造成力反馈手柄制造成本上升。为减轻使用者操纵负担并降低制造成本，本文基于二自由度力反馈手柄，提出了一种基于改进Stribeck摩擦模型的力反馈手柄力估计策略。通过建立的模型描述手柄动力学，采用改进Stribeck模型表征手柄动力学模型中非线性摩擦，并对传统Stribeck摩擦模型进行分析，对摩擦力在速度正负切换过零点时产生突变的问题进行改进，进而分析改进Stribeck摩擦模型。针对手柄系统特性，设计实验以辨识模型方程参数，通过最小二乘法对系统重力、摩擦参数进行曲线拟合，以确定相应参数。基于辨识得到的参数对手柄末端力进行估计。实验结果表明，估计的力与实际数据基本一致，验证了所提出的操纵力估计策略的准确性。

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.