基于动量偏差观测器的机器人碰撞检测算法

Collision detection algorithm for robot manipulator based on momentum deviation observer

针对机器人易与进入其工作空间的人或物体发生碰撞的问题,提出一种基于广义动量偏差观测器的碰撞检测方法来提高机器人的安全性。根据机械手广义动量与外力矩之间具有解耦性的特点,该检测算法设计了动量偏差观测器来间接获取碰撞力,并通过性能调整函数进一步改进观测器动态响应特性,进而判定碰撞是否发生。该碰撞检测算法无需外加传感器,也无需计算或检测加速度信息,可以有效避免加减速过程对碰撞检测的影响,只需检测机器人关节电机的驱动电流及编码器反馈的位置信息,即可实现碰撞实时检测。仿真和实验表明,该算法在实时性方面达到了预期要求,加减速过程对碰撞检测的扰动很小,而且能提供碰撞发生的大致位置和方向信息,对进一步的安全控制具有重要意义。

In view of the fact that robots are easy to collide with humans or obstacles which go into its workspace, a collision detection algorithm based on generalized momentum deviation was proposed to im-prove the safety of robots. According to the decoupling performance between generalized momentum and external torque of manipulator, a momentum deviation observer was firstly designed to obtain the impact force. Then, a performance regulating function was introduced to improve its dynamic response character-istics. Once impact force was detected, it is possible to judge whether the collision occurred. With this algorithm, collision can be detected in real time, and can effectively avoid the influence of acceleration or deceleration, without any additional external sensors or acceleration of the manipulator, simply by meas-uring the motor current and the position got by encoders of each joint. Simulation and experiment results show that the algorithm has reached the expected requirements in real-time performance. And the dis-turbances caused by accelerating and decelerating of manipulator are also very small. Moreover, it pro-vides an approximate position and direction of the impact force which has important significance for fur-ther security reaction control.