In recent years, the concept of droning has gradually been applied to various industries in society, such as unmanned retail, unmanned driver, unmanned factories; and related to logistics, there are unmanned sorting robots, unmanned trucks and unmanned forklifts, and more and more new equipment has been put into practical use.
Warehouse management occupies a central position in logistics management. There are many disadvantages in the traditional warehouse management, through the intelligent logistics, upgrading equipment technology, enhance the level of automation, to achieve the strategy of machine substitution, can effectively solve the existing pain points of warehouse logistics management. One of the automatic guided vehicle (Automated Guided Vehicle, AGV for short) is an essential tool in the intelligent logistics warehouse.
AGV trolley mainly realises the function of locating the position of goods, picking goods with the optimal path, and then automatically delivering the goods to the destination. Whether it is for navigation planning or obstacle avoidance, sensing the surrounding environment information is the first step. As far as obstacle avoidance is concerned, mobile robots need to obtain real-time information about the obstacles around themselves through sensors, including size, shape and location. Obstacle avoidance uses a variety of sensors, each with different principles and characteristics. At present, there are mainly ultrasonic sensors, vision sensors, laser sensors, infrared sensors and so on.
Among them, the ultrasonic sensor is a low-cost, simple to implement, mature technology solutions, which uses ultrasonic sensors to achieve obstacle avoidance, that is, through the piezoelectric or electrostatic transmitter to generate a frequency of several tens of kHz ultrasonic pulses to form a wave packet, the system detects a higher than a certain threshold value of the reversed acoustic wave, and after detection, the distance is calculated using the measured time-of-flight to obtain the information of the obstacles around itself in real time, including Size, shape and position of the obstacle, etc.
As the eyes of the robot, the AGV field of obstacle avoidance, AUDIOWELL launched a vehicle-grade ultrasonic sensors to replace the traditional infrared and laser sensors, which can help warehouse AGV in the warehouse to achieve autonomous obstacle avoidance, when a number of carts cross the road, timely and accurate parking to avoid collision. The ultrasonic sensor can detect 90° horizontal view angle, 45° vertical view angle range, and the effective detection distance is 5m, to ensure higher reliability and stability. The sensor can better avoid low obstacles on the ground than the single horizontal plane detection of 2D sweep radar.
The sensor emits ultrasonic waves and the sound travels in a conical shape, so the actual distance measured is not a point, but the distance to the nearest object within a certain conical angle. The ultrasonic sensor's built-in obstacle avoidance algorithm deeply integrates and processes all the obstacle information within the field of view, and ultimately outputs only the orientation information of the closest obstacle to the robot.
When the sensor detects an obstacle and enters into the warning area, the sensor will feedback the orientation information of the closest obstacle to the robot to the AGV control system in time, and the control system will control the robot to slow down and brake. For those obstacles that are not in the robot's forward area, even if they are close, the radar will not warn to ensure the efficiency of robot operation. When the obstacle is left or designed to bypass the obstacle, the robot can continue to work. In practical applications, only need to set the AGV vehicle width, obstacle avoidance range can be, without secondary data development.
The vehicle performs local path planning through laser point cloud combined with high-precision maps to obtain a number of trajectories to be selected. Then the obstacle information obtained by ultrasonic wave is projected and back-calculated to the vehicle coordinate system, and the selected trajectories are further screened and corrected, and the optimal trajectory is finally obtained, and the vehicle movement is controlled according to the optimal trajectory. When the vehicle is in the forward state, the distance of the obstacle obtained by the ultrasonic wave in front is less than the safe distance of the vehicle, the vehicle will make an emergency stop, and the same is true when the vehicle is in the reverse state.
Audiowell ultrasonic sensor
- Direct digital signal output
- Self-matching line, so that the probe performance to reach the optimal
- High measurement accuracy
- IP69 protection level
At present, the ultrasonic sensors researched by AUDIOWELL have been applied in AGV vehicles, intelligent robots and other products. In the future, Audiowell will be committed to become a major global supplier of sensors (position, distance, speed) and their application solutions, and invest in more focused and professional research in the sensor "perception and obstacle avoidance" distance measurement, to create a smart life with sensing technology.
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