The technical barriers of six-dimensional force sensors are high, and the humanoid robot opens up a new imagination space in the downstream
A force sensor converts the force into an electrical signal that controls the force generated by the robot. The general principle of operation of a force transducer is to respond to the applied force and convert the force value into a measurable amount. When the robot can sense the external force through the force sensor, the electrical signal is output by measuring the force value to control the terminal displacement or speed.
Six-dimensional force transducers measure forces and moments simultaneously in Cartesian coordinate systems and convert three components into electrical signals. A six-dimensional force transducer can sense six-dimensional forces and moments instead of one-dimensional data, and it can measure applied loads in any direction and in any axis. Compared with one-dimensional and three-dimensional force transducers, six-dimensional force transducers have more measurement dimensions and can measure all forces on an object in three-dimensional space.
1. One-dimensional force sensor: If the direction and application point of the force are fixed, a one-dimensional force sensor can be used for measurement.
2. Three-dimensional force sensor: if the direction of the force changes randomly in the three-dimensional space, but the action point of the force remains unchanged, and coincides with the calibration reference point of the sensor, then the three-dimensional force sensor can be used to measure the tripartite component under the calibration coordinate system.
3. Six-dimensional force sensor: if the direction of the force changes randomly in three-dimensional space, and the action point of the force does not coincide with the calibration reference point, then the six-dimensional force sensor needs to be selected to measure, and the force is decomposed into the three-way component force along the calibration coordinate axis and the three-direction moment around the calibration coordinate axis.
According to the different sensing elements, there are three basic types of six-dimensional force/torque sensors: strain gauge, optical and piezoelectric. Most of the six-dimensional force sensors used in the market are based on strain gauge measurement, and their principle is that the deformation of the strain gauge is driven by the force of the matrix, which is then converted into a change in resistance. Strain gauges are usually made of silicon or metal foil, in which the stability, signal-to-noise ratio and dynamic characteristics of silicon strain gauges are better than those of metal foil, but the cost of metal foil is superior.
The six-dimensional force sensor is one of the important sensors for the robot to achieve flexible and intelligent control.
Because the six-dimensional force sensor can accurately measure the force and provide real-time feedback to the force, it is applied in the six fields of detection, prevention, measurement, control, teaching, and protection to help the robot achieve flexible and intelligent control. Therefore, the six-dimensional force sensor can not only be applied to the operation of industrial robots such as polishing and grinding in industrial environments, but also can be applied to the screw screwing of space robots, connector assembly, and the fine control of cultural relics grasping and aquatic life capture of deep-sea robots.
Application examples of six-dimensional torque sensors:
1. Application in grinding robots: the force sensor can avoid collision and shutdown during contact sports such as assembly grinding, reduce the wear of the workpiece, and prolong the service life of the workpiece.
2. Application in rehabilitation training robot: the force sensor can accurately measure the patient's force information in the rehabilitation training process in real time, combine with expert experience, improve the patient's training method, and speed up the patient's rehabilitation.
3. Application on quadruped robots: the system can control the robot to walk and maintain balance more stably and reliably through the force information fed back in real time on the soles of the feet, and enhance the bionic function of the quadruped robot.
The concept of humanoid robots has risen, and embodied intelligence + AI has opened up the imagination space of the sensor industry and become a new opportunity for the development of the intelligent sensor industry. In 2023, Tesla has set off a new wave of humanoid robot concepts. The sensors required in the humanoid robot are different from the traditional collaborative robot, and are more suitable in its wrist, ankle link, etc. Six-dimensional torque sensor that can measure force in all directions: 1. Force control: The robot arm needs to be used for complex force control operations, such as grasping the item, assembling or slapping and other operations, and the six-dimensional force sensor can sense the force and torque exerted by the robot arm on the item, so as to facilitate the precise control of the robot control system.
2. Swing stability control: the humanoid robot needs to maintain balance in the walking process, and at this time it is necessary to the six-dimensional force sensor to sense the ground reaction force under the feet of the robot, so that the robot control system can adjust the posture of the humanoid robot arm and the body.
3. Safety control: The six-dimensional force sensor can be used in the safety control system to realize the automatic stop of the robot before the dangerous operation or when the human approaches the robot, so as to avoid causing harm to the human body.
The technical barriers of six-dimensional force sensors are high, and it is difficult to design structures, dynamic and static calibration, decoupling, and dynamic and static calibration.
The six-dimensional force/torque sensor can sense the six-dimensional force and torque information, and can measure the application load in any direction and any axis, but it is not a simple superposition of three one-dimensional force transducers and three torque transducer structures, and its nonlinear mechanical characteristics are obvious. Therefore, in addition to solving the monotonicity and uniformity problems that are sensitive to the measured force components, the multi-dimensional force sensor also needs to solve the interdimensional disturbance problems caused by structural processing and process deviations, the dynamic and static calibration problems, and the decoupling algorithms and circuit implementations in vector operations.
1. Structural design: The elastomer structure of the six-dimensional force sensor affects the key performance of the sensor, such as sensitivity, rigidity, dynamic performance, and interdimensional coupling. A good elastomer structure should have the following qualities:
1) The strain beam should have good sensitivity to the force measured by the dimension;
2) The strain beam should be very insensitive to the non-measured force, and it is ineffective in principle. That is, the coupling between dimensions is small;
3) The whole structure has sufficient rigidity;
4) the sensor base coordinates are clear;
5) Good structural symmetry;
6) Easy to connect and install externally;
7) is convenient for machining, or the processing difficulty is reasonable, and it is easy to realize the intention of structural design;
8) The patch is convenient, or the difficulty of the patch is reasonable, and the accuracy of the patch position is easy to check and measure;
9) It is convenient to realize mechanical overload protection measures, and it is not too difficult to adjust.
2. Dynamic and static calibration: scientific and accurate calibration can effectively improve the accuracy of the six-dimensional force sensor. Calibration is to measure the performance indicators of the sensor, which can be divided into two types: static calibration and dynamic calibration. The purpose of static calibration is to determine the static characteristics of the sensor, such as linearity, sensitivity hysteresis, and repeatability. The purpose of dynamic calibration is to determine the dynamic characteristics of the sensor, such as frequency response, time constant, natural frequency, and damping ratio.
3. Decoupling: Interdimensional coupling is the main factor affecting the measurement accuracy of multi-dimensional force/torque sensors. Coupling refers to the phenomenon of two forms of movement or between two or more systems that interact with each other to the point of union. The input signal of each loop in a "coupled" system has an effect on the output of all loops, and the output of each loop is affected by all inputs.
4. Circuit realization: the coupling deformation can be greatly reduced by adjusting the structural design of the elastomer, but the continuity of the structure leads to the inability to completely avoid the coupling deformation. In this case, the coupling needs to be eliminated by adjusting the position of the patch and designing the bridge. The correlation between the strain and the position of the structural surface can be obtained according to the simulation, so as to determine the maximum strain position of the circumferential beam and the radial beam surface of the six-dimensional force transducer under each working condition for pasting the strain gauge, and then further design the strain gauge patch and bridging scheme.
In recent years, there has been an increase in the number of domestic manufacturers entering the field of six-dimensional force/torque sensors, but there are few manufacturers with the ability to manufacture high-performance products. In recent years, Kunwei Technology, Yuli Instrument, Xin Jingcheng, Hypersen, Blue Dot Touch, Shenyuansheng Intelligence, Realt Measurement and Control and other companies have all implemented six-dimensional force related products and entered industrial applications. Other manufacturers, such as Chongqing Luban Robotics Research Institute, also have a six-dimensional force production capacity through independent research and development of force sensor technology. Among the domestic sensor manufacturers, only Kunwei Technology's six-dimensional force sensor has an accuracy of ≤ 0.5%, which is benchmarked against ATI, an international leader in six-dimensional force.
In the 22-year Liuweili market, Kunwei Technology, ATI, Yuli Instrument, and Xin Jingcheng have the largest shipments, and their downstream applications are different.
According to the 22 years of domestic market sales caliber, ATI, Yuli Instrument, Kunwei Technology, Xin Jingcheng are in the first echelon of the domestic six-dimensional force market, but the focus of each manufacturer in the downstream application is different:
1) Kunwei Technology: Kunwei Technology has obvious advantages in the fields of collaborative robots, medical surgical robots, medical testing robots and rehabilitation robots, and its products have core competitiveness in various industries in the aerospace field;
2) ATI: As a global leader, ATI has a relatively wider range of applications after years of accumulation;
3) Yuli Technology: Yuli Instrument is more used in the industrial robot grinding and polishing industry and the automobile crash test industry;
4) Xin Jingcheng: Xin Jingcheng has pushed its products into the 3C industry by virtue of its identity as an Apple supplier, and also has a layout in the robot industry and the medical industry.
The six-dimensional force/torque sensor is the key to the smooth and intelligent control of robots, and its application in the field of robots occupies a large market share. According to the data of high-tech robots:
1) Sales of six-dimensional force: In 2022, 8,360 sets of six-dimensional force/torque sensors will be sold in the domestic market, of which 4,840 sets will be sold in the robot industry, accounting for 57.89%, a year-on-year increase of 62.58%.
2) Six-dimensional force market size: In 2022, China's six-dimensional force/torque sensor market size will be 239 million yuan, of which the six-dimensional force/torque sensor market size in the robot industry will be 156 million yuan, accounting for 65.27%, a year-on-year increase of 54.35%.
From the perspective of overall shipments, the market base of six-dimensional force/torque sensor is small, and no obvious scale effect has been formed. With the breakthrough of the six-dimensional force downstream application scenario brought by the humanoid robot industry, the number of entrants has continued to increase in recent years, and the market awareness has been improved year by year, and the six-dimensional force/torque sensor is expected to enter a period of rapid growth. GGII predicts that in 2027, the sales volume of six-dimensional torque sensors in the domestic market is expected to exceed 84,000 sets, with a compound growth rate of 58.64%, of which the sales volume of the robot industry is expected to exceed 42,000 sets, and the domestic six-dimensional force/torque sensor market will exceed 1.5 billion yuan, with a compound growth rate of 44.39%.
Keli Sensing: a leader in the intelligent sensor industry, with a stable financial position and a long-term investment in high R&D
Founded in 1995, the company has been committed to the development and production of various types of physical quantity sensors, as well as different industrial IoT systems and multi-scene application solutions, and has ranked first in the domestic load cell market share for 14 consecutive years. The company has more than 20 wholly-owned subsidiaries and holding subsidiaries, involving production, trade, information services, equipment manufacturing and other fields, forming a whole industry chain covering and empowering the group to continue.
Adhering to the "two-legged walk", strain sensors and system integration products are the main sources of revenue. The company adheres to the "two-legged walk" at the level of the main business.
On the one hand, the development and production of multi-physical quantity sensors, weighing instruments, electronic weighing systems, industrial Internet of Things system complete sets of equipment.
On the other hand, it provides industrial IoT system solutions such as non-stop detection system and construction machinery Internet of Things.
Among the many operating products, strain sensors and system integration products accounted for the largest proportion of revenue, accounting for 52.28% and 19.84% of revenue in 22 years, respectively.
1. Strain gauge sensor
A sensor is a device that can convert non-electrical physical, chemical, and biomass into electrical signals or other usable signals, which can make lifeless objects have senses such as touch, sight, taste, and smell, and make objects "live". And the strain gauge sensor can convert the deformation of the engineering component after being stressed into a measurable resistance change through the strain gauge device, and its working principle is to bond the strain-sensitive variable resistor to the member, and the matrix force drives the strain gauge to deform, and then the resistance value of the strain gauge changes, and the output is proportional to the weight value.
The company takes strain sensors as the core of its business operations, and although the proportion of strain sensor revenue has been decreasing year by year in the past five years, it has remained above 50% in 22 years, accounting for 52.28%. The gross profit margin of the strain gauge business in '22 increased by 4.01 percentage points from '21 to 37.29%.
Strain gauge sensor manufacturers can be divided into three echelons:
1) The first echelon. Mainly multinational companies, such as Vishay in the United States, HBM in Germany, Flintec in Switzerland, etc.;
2) Second echelon. The regional leading enterprises represented by Keli Sensing and China Avionics Measurement are the mainstays, and they have their own strengths in market segments, product prices and downstream applications;
3) The third echelon. China, South Korea and other countries of low-end product manufacturers, their products are mainly sold in China, competitiveness is mainly reflected in the relatively low labor costs, but the technical level is relatively low, can not participate in the global market competition.
2. System integration products
From 2017 to 2022, system integration products accounted for nearly 20% of revenue, and gross profit margins remained at a high level, at 50.78%, 58.96%, 51.99%, 43.18%, and 39.28%, respectively. Due to the particularity of customization of system integration products, it is difficult to carry out standardized, large-scale, and balanced production, and the production plan cannot be arranged according to reasonable stocks, so it is impossible to adopt the production mode of "inventory production", and the production mode of "production by sales" needs to be adopted.
The company has a strong financial position and abundant cash flow
The company's revenue in 20 and 21 years increased rapidly, with a year-on-year growth rate of 12.82% and 23.44%. In 22 years, the company's sensor sales were 2.9936 million, with a growth rate of only 4.09%, a sharp decline compared with 21 years, resulting in a slowdown in the growth rate of operating income in 22 years, only 2.85%.
The company's gross profit margin is above 40% all year round, and the net profit margin of sales has been above 20% in the past four years, and the company's profit level is relatively high. In the first three quarters of 2021-2023, the company's gross profit margin and net profit margin increased year by year, with gross profit margins of 38.31%, 40.24%, and 42.64%, respectively, and net profit margins of 24.84%, 25.99%, and 28.55%, respectively.
In the first three quarters of 2021-2023, the sum of the company's monetary funds and easily realizable trading financial assets exceeded 1 billion yuan, with abundant liquidity and high asset quality. From 2019 to Q3 2023, the company maintained a large number of strong liquid assets, but with the increase of short-term borrowings year by year, the quick ratio fell sharply, but it still maintained a high short-term solvency. At present, the company's quick ratio is at the middle level of the same industry, indicating that compared with the same industry, the company has a strong solvency and a higher efficiency of capital use.
After 2019, the company's investment projects increased, and the cash paid for investment in the first three quarters of 2020-2023 was 13.92/20.37/16.74/730 million yuan, respectively, mainly due to the company's large-scale acquisition and merger plan. The company plans to invest in different targets in different ways such as holding, mergers and acquisitions, equity investment, etc., around the five major directions (force-sensitive sensors + other physical sensors + intelligent logistics equipment + industrial IoT automation equipment + Internet of Things platform projects), so as to enhance the key effectiveness of investment in the company's development process. The net cash flow generated by the company's operating activities is always positive, the cash flow is healthy, and the company's own hematopoietic ability is strong, which can provide strong financial guarantee for the company's subsequent investment activities.
Forge ahead to create a multi-physical quantity sensor "hexagonal warrior", and epitaxial endogenous deep map remote basket robot sensor field
In 2023, the company will make efforts to invest in foreign investment: in terms of sensor enterprises, covering a variety of physical quantity sensors such as electricity + safety grating + laser measurement + vision, and in terms of Internet of Things enterprises, it will deepen the industrial chain by covering food + new energy automation equipment + coal mine Internet of Things business.
1) Multi-physical quantity sensors: In 2023, the company will accelerate the pace of investment and participate in a number of sensor companies. In February, the company's strategic investment focused on the development and production of safety gratings, and the layout of the power sensor industry - reached a strategic cooperation agreement with Shenzhen Sandian and Science and Technology Innovation Board Minxin Co., Ltd.; in July, the company completed the investment in CMOS laser measurement sensor developer Dianlian Sensing and high-end industrial vision sensor company Liyi Technology; in August, the strategic investment in domestic industrial sensor high-end brands Wance and Weiqin Electronics, of which Weiqin Electronics is the domestic comparison As a scarce multi-sensor fusion technology team, it took the lead in developing a set of digital sensor technology platform in China.
2) Depth of the industrial chain: In May, the company took a stake in Chengdu Haike, mainly manufacturing Chinese food automation production line, Haike's high-end intelligent production line and automated production equipment will provide business scenarios and application platforms in the field of food automation and industrial robots for the integration of the company's force-sensitive sensors and multi-physical sensors; In September, the company plans to acquire Huahong Technology, a leading enterprise in the mine geophysical prospecting instrument industry, through its own funds to broaden the application landscape of industrial Internet of Things.
Through horizontal investment layout, a variety of physical quantity sensors are covered:
1) Traditional load cells. The parent company, Keli Sensing, mainly produces and sells traditional load cells, and also develops miniature sensors and torque sensors;
2) Other physical quantity sensors: Yipuxing, Shenzhen Sandian, Yuyao Yinhuan, Chicheng Electric, and Liyi Technology have made achievements in safety grating, electricity, flowmeter, gas, and displacement sensors respectively;
3) Multi-physical quantity sensors: The company's strategic investment in Bay Test Technology and Weiqin Electronics are comprehensive sensor companies, which in the Bay Test Technology to develop laser displacement, optical fiber, proximity, safety grating and other types of sensors, Weiqin Electronics to develop pressure, temperature and humidity, liquid level, inclination, laser particles and other kinds of sensors.
The epitaxial promotion robot sensor seed project reserve, and the endogenous research and development trial production of multi-dimensional force sensors
In the first half of 2023, in the face of the industrial development opportunities brought by humanoid robots, the company will "take the market as a teacher", accelerate independent research and development on the basis of the existing high-end machine sensor categories such as micro, torque, and multi-dimensional force, and actively seek business cooperation with major robot manufacturers. According to the different needs of customers, the company has carried out a variety of torque sensors, multi-dimensional force sensors and other products to send samples and trial production. As of the end of June 2023, the company has reserved a number of robot sensor seed projects with high technical barriers and broad market prospects, making all-round preparations for the next stage of seizing the development opportunities in the field of humanoid robot sensors.
The company's strain gauge sensor placement process can be applied to six-dimensional force sensors.
The chip is to paste the sensitive component on the elastic element, change the resistance value through the mechanical deformation of the metal, and obtain the change of the electrical signal to obtain the strain, which is required for the production of traditional strain gauge sensors and six-dimensional force sensors. The application landscape of six-dimensional force sensors is complex and diverse, and its structure also presents diverse characteristics. When strain gauge diameters are reduced, manual placement is difficult, and the company's automated placement process will reduce production time and improve consistency.
The research and development of multi-dimensional force sensors is carried out endogenously, and it is currently in the stage of small-batch trial production. The three-dimensional force, six-dimensional force and other multi-dimensional force sensors developed by the company can be used for robot arm motion and work load monitoring, curved surface grinding and polishing, machining center carving processing, medical equipment precision measurement and control, etc., with high precision, high sensitivity, strong anti-eccentric load capacity, small interdimensional coupling and other characteristics. As of July 2023, the company's multi-dimensional series products are still in the trial production stage of small batches.
Acquired Hua Hong Technology to expand downstream industrial Internet of Things application scenarios
The Company intends to use its own funds of RMB 65 million to acquire Fuzhou Huahong Intelligent Technology Co., Ltd. (hereinafter referred to as "Huahong Technology"), and control the voting rights of 22.43 million shares of Huahong Technology in total, accounting for 52.77% of the total number of voting shares after the completion of Huahong Technology's directional issuance of shares, and successfully obtaining control of Huahong Technology.
Hua Hong Technology's main business is the research, development and sales of technical equipment in the field of mine geophysical exploration and its services, which has formed core technical advantages in the field of mine geophysical prospecting and shallow geophysical exploration, and the company's products account for more than 30% of the sales share of the domestic similar product market, and its production, sales and research and development capabilities rank among the top three in the same industry nationwide. In December 2013, Hua Hong Technology was awarded the "Engineering Technology Research Center of Fujian Mine Geophysical Prospecting Technology and Equipment Enterprise", and was officially listed on the New Third Board of the National Small and Medium-sized Enterprise Share Transfer System on June 24, 2014, and was rated as a "specialized, special and new" small giant enterprise in 2021.
The multi-dimensional force sensor developed by the company is in the sample delivery stage, and is currently actively seeking business cooperation opportunities with major robot manufacturers, and has reserved a number of robot sensor seed projects with high technical barriers and wide market prospects. The company's business is expected to gain new incremental space with the development of the humanoid robot industry, and we expect this business to have a rapid growth rate in the future.
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