A universal algorithm for sensorless collision detection of robot actuator faults

Abstract

When a robot is working properly, it is possible to collide with people or objects entering its working space. This research is different than usual control algorithm. It proposes a universal algorithm for sensorless collision detection of robot actuator faults to enhance the security of the robot. On the basis of the dynamic model, a classical friction model to ensure the accuracy of the whole dynamic model is introduced. This collision detection algorithm can conduct without any external sensors or acceleration and realize the real-time detection just needs to measure the motor current and the location information from the encoder of the robot joint. The value of external torque t ext was used to compare with the threshold to detect the collision. After using the proposed collision detection method, the two rotational (2R) planar manipulators can detect the slight collision reliably. The experimental results and performance comparisons show that this sensorless collision detection algorithm is simple and effective. It can be promoted to any other type of robot arm with more degrees of freedom.

Challenges for Novice Developers in Rough Terrain Rescue Robots: A Survey on Motion Control Systems

“…Many of these studies focus on the best technique to employ in getting rid of collision when using rescue robots. For instance, in a study titled "A Universal Algorithm for Sensorless Collision Detection of Robot Actuator Faults," Chen et al came up with a universal algorithm for a sensorless collision detection of robot [30]. This control system differs from the normal control algorithm significantly.…”

Flexible Joints of Picking Manipulator Based on Current Feedback

“…For example, Wahrburg et al [10] presented a Kalman filterbased approach for estimating external forces and torques relying on a dynamic model of a serial-chain robotic manipulator where only motor signals (currents, joint angles, and joint speeds) are measurable. Chen et al [11] proposed a universal algorithm for the sensorless collision detection of robot actuator faults to enhance the security of the robot. This collision detection algorithm can be implemented without any external sensors or acceleration and can realize realtime detection just needed to measure the motor current and the location information from the encoder of the robot joint.…”

“…To protect against collisions of the picking manipulator, this article proposes flexible joints based on an elastic actuator that can partly absorb the shock of an impact during collisions involving the manipulator and can help reduce damage to the manipulator and plants. At the same time, the collision detection algorithm is designed based on the current feedback of the joint motor inspired by the third method above [11], [12]. The collision detection algorithm is used to establish a control system for flexible joints of the picking manipulator based on moment feedback.…”

Adaptive threshold for robot manipulator collision detection using fuzzy system

“…Although this method can detect the collision force accurately, it can just detect the collision where the sensor is located; moreover, it is an expensive solution. In order to cope with the problems of utilizing external sensors, there are other collision/interaction detection techniques without using external sensors (sensor-less) proposed in the literature [25][26][27][28][29][30]. These methods are able to extract more information from a physical collision and efficiently estimate the actual joints torque due to collision, but it required reliable information on full dynamic model, or at least the gravity model as in [31,32], which might not be available for many of the industrial robots.…”