What are the core technologies of service robots?

Services can be seen as helpers in our daily work. Service robots can be found around us, such as in our homes and gardens (such as robot vacuum cleaners or lawn mowers), or in professional environments, taking over daily tasks to improve efficiency. Although the terminals are easy to use, the design of such devices is extremely complex, resulting in smooth user-friendly operation. It can be used on mobile devices to enable them to perform operations accurately. Advanced functions such as collision avoidance or room modeling require built-in radar and. The advanced models on board the robot will use learning to achieve path planning. Users can benefit from these functions, such as reducing task completion time.

For example, the above picture shows that these robots are actually the most basic prototypes of service robots. They all have a certain degree of autonomy, can move in the corresponding environment and perform the expected tasks, and provide a high level of assistance and simplicity in home or professional environments.

So, what can service robots do? What kind of people and scenarios do they serve? They can be divided into three categories:

1) Medical service robots (B-end products): intelligent blood collection robots, isolation ward patrol robots, disinfection robots

2) Commercial service robots (B-end products): food delivery robots, guidance robots, service robots, security patrol robots, etc.

3) Household service robots (C-end products): tool robots (such as smart sweeping robots), educational robots, etc.

Among them, commercial service robots have developed rapidly in recent years and have become increasingly mature. However, they will encounter various problems in the service process. For example, taking the delivery service robot as an example, its main function is to deliver express packages. However, one of the difficulties of delivery service robots is how to control the elevator, automatically enter the elevator and reach the corresponding floor when it is necessary to go up and down the stairs.

The basic architecture of a robot usually includes a central control unit, a battery charger, a communication module, a human-machine interface (HMI), sensors, and a drive module (brushless and). So, what are the core technologies of a service robot? You can immediately know from a functional module diagram of a service robot:

Among the current service robot functions, human-machine interaction, environmental perception and motion control are the three core functions. Environmental perception is like the robot's eyes, guiding the robot's motion control, so that it can go to the designated location and complete the designated service. In the service process, human-machine interaction is an indispensable function.

For service robots, the interactive system includes UI interface, facial recognition, payment system, etc. This is a function directly facing users and the most direct embodiment of "service". Environmental perception and motion control are inseparable, and the two can only complete the service when they cooperate with each other. Why do we say this?

If robots want to complete services and reach designated locations, they need precise motion control. To achieve precision, they rely on various sensors.

The general environment perception and block diagram of the service robot are as follows:

The entire system includes: system, drive system, control system, power system, and the environment transmitted by the sensor system.

Sensors are the eyes of robots. Their functions in different scenarios are similar, which is to enable robots to "see". In the entire robot motion control system, the following sensor systems are commonly used in service robots:

Combined with the control system block diagram, these sensors in the upper layer of the application can be summarized as external sensor systems, which mainly perform two functions:

1) Map construction: Use lidar or camera to construct a 2D grid map or 3D point cloud map of the 3D environment;

2) Use maps: The robot calculates sensor data in real time during operation, and uses algorithms such as subgraph matching to match the known map to obtain positioning and obstacles.

In environmental perception, the main problems are as follows:

1. Highly dynamic environments lead to map building failure or positioning failure. The robot relies on the assumption that the environment remains unchanged during map building. Although certain algorithms can be used to avoid the impact of dynamic environments, it cannot completely guarantee that the robot can work normally.

2. The problem of the long-term life cycle of the map. Usually, if the environment changes, the robot needs to re-build the map, otherwise it will not work.

3. High-precision point cloud maps rely on expensive lidar sensors, complex algorithms, and a large amount of computing resources, and high-precision point cloud maps are difficult to obtain.

There are also various problems in the sensor system at the bottom of the hardware. The internal sensors at the bottom of the hardware are mainly responsible for collecting information from the drive system, mainly motor movement information, including motor speed, motor angle, etc. Most brushless motors currently have their own. Due to the high speed of brushless motors, which can reach tens of thousands of revolutions per minute, there are very high requirements for the accuracy and stability of the encoding sensor. Traditional grating encoders are increasingly unable to adapt to the high-speed characteristics of brushless motors, and encoders are gradually being replaced by magnetic encoders.

Editor: Huang Fei