A mobile robot is a machine which can work automatically. The mobile robot can be operated under the command of human operators or in pre-programmed programs, and can act according to principles set out by the artificial intelligence technology as well. This type of mobile robot can be used indoors or outdoors, and can be used in industry, business or household. For example, the mobile robot can be used to replace security guards to perform patrol, or replace people to clean the surface. The mobile robot can also be used to accompany family members or assist in doing office work.
When mobile robot like cleaning robot, accompanying robot or guest-guiding robot moves under an operating mode, due to the complexity of the operating environments, the mobile robot may often hit obstacles so as to damage furniture and itself in the operating process because of an unfavorable obstacle avoidance performance thereof, thereby influencing normal operation of the mobile robot. Wheels of the mobile robot often get entangled with some flexible obstacles (e.g., cables, ropes, ribbons, leftover of cloth), so that the mobile robot cannot move, and even the mobile robot may tip over to cause safety accidents. For a cleaning robot, the cleaning system of the cleaning robot may be more likely to be entangled by flexible obstacles, for example, cleaning brushes may be entangled by flexible obstacles, or a dust collection component may be entangled or blocked by flexible obstacles.
Generally speaking, in order to detect obstacles on the floor such as ground in time, obstacle detection technologies often adopted on the existing mobile robot are mainly as follows:
Mechanical collision detection: a mechanical baffle connected with an electronic switch is arranged at the front of the bottom of the mobile robot, when the mobile robot comes into contact with obstacles, the electronic switch is converted into a connected state from a disconnected state, so as obstacles in the front can be detected. In this way, detection of obstacle can be performed only after collision occurs, and thus contribute to a poor user experience. Moreover, flexible obstacles are easily pushed away by the mobile robot, the electronic switch cannot be triggered because the collision force between robot and obstacles is too small, thereby leading to a missing detection.
Infrared distance measurement detection: one or more infrared distance measurement sensors are arranged on the mobile robot. And obstacles in the front can be detected in the case of the detected distance is smaller than a preset threshold. However, infrared detection is greatly influenced by ambient lighting, and there is a greater dead zone within a short distance. Obstacles made from glass, light-absorbing or all-black materials are easily missed in detection, and the consistency of precisions is poor. Because of the structure limitations, the infrared sensor cannot be arranged on the lower part of housing, thus some obstacles which are lower than the infrared rays, e.g., flexible obstacles, may be missed in detection.
Ultrasonic distance measurement detection: one or more ultrasonic distance measurement sensors are arranged on the mobile robot. And obstacles in the front can be detected in the case of the detected distance is smaller than a preset threshold. However, on the one hand, ultrasonic waves are easily influenced by factors such as ambient temperature, material of reflectors and multipath propagation of sound waves. On the other hand, Because of the structure limitations, the ultrasonic sensor cannot be arranged on the lower part of housing, thus some obstacles which are lower than the ultrasonic waves, e.g., flexible obstacles, may be missed in detection. In addition, another limitation of ultrasonic measurement is that it depends on the effective reflection area of the obstacle, such that object with a size greater than a certain threshold can be detected, smaller object such as wires can be easily missed.
Therefore, it can be seen that the detection of flexible obstacles is the problem that needs to be solved urgently for the existing mobile robot.